MIC2870
1.5A Synchronous Boost Flash LED Driver with
I2C Interface
Features
General Description
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The MIC2870 is a high-current, high-efficiency flash LED
driver for one or two high-brightness camera flash LEDs.
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Up to 1.5A Flash LED Driving Current
2.7V to 5.0V Input Voltage Range
High-Efficiency 2 MHz VF Adaptive Boost Driver
Configurable 1 or 2 Channel(s) WLED Driver
LED Driving Current Soft-Start
Control through I2C Interface or External Pins
Flash Inhibit Function for GSM Pulse
Synchronization
True Load Disconnect
Flash Time-Out Protection
1 µA Shutdown Current
Available in 16-Pin 2 mm x 2 mm TQFN Package
Applications
• Camera Phones/Mobile Handsets
• Cellular Phones/Smartphones
• LED Light for Image Capture/Auto-Focus/
White Balance
• Handset Video Light (Torch Light)
• Digital Cameras
• Portable Applications
2018 Microchip Technology Inc.
The LED drive current is generated by an integrated
inductive boost converter with 2 MHz switching
frequency, which allows the use of a very small inductor
and output capacitor. These features make the MIC2870
an ideal solution for high-resolution camera phone LED
flashlight driver applications.
MIC2870 supports two 750 mA white LEDs (WLEDs) or
a single 1.5A WLED configuration. When two WLEDs
are connected, their currents are matched automatically.
MIC2870 operates in either Flash or Torch mode that can
be controlled through either an I2C interface or external
pins. The brightness in the Flash and Torch mode can be
adjusted via two external resistors individually. The
high-speed mode I2C interface provides a simple control
at a clock speed up to 3.4 MHz to support most camera
functions, such as auto-focus, white balance, and image
capture (Flash mode).
The MIC2870 is available in 16-pin, 2 mm x 2 mm TQFN
package with a junction temperature range of –40°C to
+125°C.
DS20006078A-page 1
MIC2870
Package Type
FEN
3
FI
4
Note: Thin QFN Pin 1 identifier = “
PGND
SW
EN
13
EP
5
6
7
12
OUT
11
TEN
10
LED1
9
LED2
8
TRSET
2
14
PGND
VIN
15
AGND
1
16
FRSET
SCL
SDA
MIC2870
16-Pin 2 mm x 2 mm TQFN
(Top View)
”.
Typical Application Schematic
VBAT
VIN
4.7 μF
SW
OUT
1 μF
2.2 μF
AGND
LED1
LED2
PGND
MIC2870 ePAD
ENABLE
FLASH ENABLE
TORCH ENABLE
FLASH INHIBIT
EN
FEN
TEN
FI
FRSET
TRSET
SDA
SCL
10 k
10 k
AGND
VBAT
I2C MASTER
DS20006078A-page 2
2018 Microchip Technology Inc.
MIC2870
Functional Block Diagram
SW
OUT
OVP
DIE TEMP
VIN
5.38V/
5.32V
160°C/
135°C
BODY
SWITCH
EN
VIN
OUT
SAFETY TIMER
2.5V/
2.2V
UVLO
FI
SYSTEM
CONTROL
LOGIC +
ANTI-CROSS
CONDUCTION
FEN
PGND
PGND
TEN
2 MHz
OSCILLATOR
SCL
AGND
I2C
INTERFACE
SDA
DUPLICATE FOR LED1, LED2
LED 0.6V
LED SCP
OUT
25 mV
Z
Z
LED1
LED OPEN
V/I
LED
LED2
SAFETY TIMER
SAFETY TIMER
AGND
2018 Microchip Technology Inc.
TRSET
FRSET
PGND
DS20006078A-page 3
MIC2870
1.0
ELECTRICAL CHARACTERISTICS
Absolute Maximum Ratings†
Supply Voltage (VIN)................................................................................................................................... -0.3V to +6.0V
Enable Input Voltage (VEN, VFEN, VFI, VTEN) ......................................................................................-0.3V to VIN + 0.3V
VOUT, VLED1, and VLED2 ............................................................................................................................. -0.3V to +6.0V
I2C I/O (VSCL, VSDA)............................................................................................................................-0.3V to VIN + 0.3V
VFRSET and VTRSET .............................................................................................................................-0.3V to VIN + 0.3V
VSW ............................................................................................................................................................ -0.3V to +6.0V
Power Dissipation(1) (PDISS) ..................................................................................................................Internally Limited
ESD Rating(2) ............................................................................................................................ 2 kV HBM and 150V MM
†
Notice: Stresses above those listed under “Maximum Ratings” may cause permanent damage to the device. This
is a stress rating only and functional operation of the device at those or any other conditions above those indicated in the operational sections of this specification is not intended. Exposure to maximum rating conditions for
extended periods may affect device reliability.
Note 1:
2:
The maximum allowable power dissipation at any TA (ambient temperature) is PDISS(max) = (TJ(max) – TA)/JA.
Exceeding the maximum allowable power dissipation will result in excessive die temperature and the regulator
will go into thermal shutdown.
Devices are ESD-sensitive. Handling precautions are recommended. Human body model, 1.5 k in series
with 100 pF.
Operating Ratings(1)
Supply Voltage (VIN).................................................................................................................................. +2.7V to +5.0V
Enable Input Voltage (VEN, VFEN, VFI, VTEN) ..................................................................................................... 0V to VIN
I2C I/O (VSCL, VSDA)........................................................................................................................................... 0V to VIN
Note 1:
The device is not ensured to function outside the operating range.
DS20006078A-page 4
2018 Microchip Technology Inc.
MIC2870
TABLE 1-1:
ELECTRICAL CHARACTERISTICS(1)
Electrical Specifications: unless otherwise specified, VIN = 3.6V; L = 1 µH; COUT = 2.2 µF; RFRSET = 10 k;
RTRSET = 10 k; ILED = 100 mA; TA = TJ = +25°C. Boldface values indicate -40°C TJ +125°C.
Parameter
Symbol
Min.
Typ.
Max.
Units
VIN
2.7
—
5.0
V
—
0.9
—
—
4.2
—
—
0.6
—
µA
Test Conditions
Power Supply
Input Voltage
Quiescent Current
mA
IVIN
Shutdown Current
IVIN(SD)
—
VLED1 = VLED2 > 200 mV,
not switching (Note 2)
VLED1 = VLED2 = 70 mV,
boost keeps switching (Note 2)
VEN = 0V (Note 2)
SW Pin Shutdown Current
ISW(SD)
—
1
5
µA
VEN = 0V
UVLO Threshold (Rising)
UVLO_Rise
2.35
2.5
2.65
V
—
UVLO Hysteresis
UVLO_Hyst
mV
—
300
—
—
—
VIN
—
—
5.2
Output Voltage
VOUT
Overvoltage Protection
Threshold
VOVP
5.26
5.38
5.6
V
Overvoltage Protection
Hysteresis
VOVP_HYS
—
60
—
mV
OVP Blanking Time
Maximum Duty Cycle
V
(Note 2)
VIN VOUT
VOUT > VIN
VOUT > VIN
(Note 2)
TBLANK_OVP
—
24
—
µs
(Note 2)
DMAX
80
85
90
%
—
Minimum Duty Cycle
DMIN
—
5.5
—
%
(Note 2)
Switch Current Limit
ISW_OC
3.35
4.5
5.65
A
VIN = VOUT = 2.7V
Oscillator Frequency
FSW
1.8
2.0
2.2
RON(N)
—
80
—
RON(P)
—
80
—
NMOS Switch Leakage
Current
ILK(N)
—
1
5
µA
VEN = 0V,
VIN = VSW = VOUT = 5V
PMOS Switch Leakage
Current
ILK(P)
—
1
5
µA
VEN = 0V, VIN = VOUT = 5V,
VSW = 0V
Auto-Discharge NMOS
Resistance
RDCHG
—
160
—
VEN = 0V, IOUT = -1 mA
(Note 2)
Overtemperature Shutdown
Threshold
TSD
—
160
—
°C
(Note 2)
Overtemperature Shutdown
Hysteresis
TSD_HYST
—
25
—
°C
(Note 2)
TFLASH_TIMEOUT
—
1.25
—
s
Maximum time-out setting
(Note 2)
Channel Current Accuracy
AccuLED_Ch
-10
—
10
%
VLED1 = VLED2 = 890 mV,
ILED1 = ILED2 = 750 mA
Channel Current Matching
MatchLED_Ch
-5
—
5
%
VLED1 = VLED2 = 890 mV,
ILED1 = ILED2 = 750 mA
VDROPOUT
—
100
—
mV
m
Switch-on Resistance
Flash Safety Time-out
Shutdown
MHz —
VVIN = 2.7V, ISW = 750 mA
(Note 2)
VSW = 2.7V, IOUT = 750 mA
(Note 2)
Current Sink Channels
Current Sink Dropout
Note 1:
2:
Boost is in regulation (Note 2)
Specification for packaged product only.
Specifications are obtained by design and characterization; not 100% tested in production.
2018 Microchip Technology Inc.
DS20006078A-page 5
MIC2870
TABLE 1-1:
ELECTRICAL CHARACTERISTICS(1) (CONTINUED)
Electrical Specifications: unless otherwise specified, VIN = 3.6V; L = 1 µH; COUT = 2.2 µF; RFRSET = 10 k;
RTRSET = 10 k; ILED = 100 mA; TA = TJ = +25°C. Boldface values indicate -40°C TJ +125°C.
Parameter
Symbol
Min.
Typ.
Max.
Units
Test Conditions
LED1 Leakage Current
ILK_LED1
—
0.05
—
µA
VIN = 3.6V, VEN = 0V,
VLED1 = 3.6V (Note 2)
LED2 Leakage Current
ILK_LED2
—
0.05
—
µA
VIN = 3.6V, VEN = 0V,
VLED2 = 3.6V (Note 2)
FRSET Pin Voltage
VFRSET
0.970
1.00
1.030
V
RFRSET = 10 k, Flash mode
FRSET Current Sourcing
IFRSET
90
100
110
µA
FRSET pin is shorted to ground,
Flash mode
TRSET Pin Voltage
VTRSET
0.970
1.00
1.030
V
RTRSET = 10 k, Torch mode
TRSET Current Sourcing
ITRSET
90
100
110
µA
TRSET pin is shorted to ground,
Torch mode
EN High-Level Voltage
VEN_ON
1.5
—
—
V
Boost converter and chip logic
on
EN Low-Level Voltage
VEN_OFF
—
—
0.4
V
Boost converter and chip logic
off
FEN High-Level Voltage
VFEN_ON
1.5
—
—
V
Flash on
FEN Low-Level Voltage
VFEN_OFF
—
—
0.4
V
Flash off
TEN High-Level Voltage
VTEN_ON
1.5
—
—
V
Torch on
TEN Low-Level Voltage
EN/FEN/TEN/FI Control Pins
VTEN_OFF
—
—
0.4
V
Torch off
FI High-Level Voltage
VFI_ON
1.5
—
—
V
Flash inhibit on
FI Low-Level Voltage
VFI_OFF
—
—
0.4
V
Flash inhibit off
EN Pin Current
—
—
2
5
µA
VEN = 5V
FEN/TEN/FI Pin Current
—
—
1
5
µA
VFEN = VTEN = VFI = 5V
tBlank_EN_Off
0.90
1.10
1.30
s
EN Off Blanking Time
EN pin should be driven low for
more than this time before the IC
enters Sleep mode
I2C Interface – SCL/SDA Pins (Ensured by Design)
Maximum Operating
Frequency
fSCL
—
—
3.4
Low-Level Input Voltage
VIL
—
—
0.4
V
—
VIH
1.5
—
—
V
—
RSDA_DN
—
20
—
(Note 2)
High-Level Input Voltage
SDA Pull-Down Resistance
Note 1:
2:
MHz —
Specification for packaged product only.
Specifications are obtained by design and characterization; not 100% tested in production.
DS20006078A-page 6
2018 Microchip Technology Inc.
MIC2870
TABLE 1-1:
ELECTRICAL CHARACTERISTICS(1) (CONTINUED)
Electrical Specifications: unless otherwise specified, VIN = 3.6V; L = 1 µH; COUT = 2.2 µF; RFRSET = 10 k;
RTRSET = 10 k; ILED = 100 mA; TA = TJ = +25°C. Boldface values indicate -40°C TJ +125°C.
Parameter
Symbol
Min.
Typ.
Max.
Units
Test Conditions
LED1/LED2 Open Detect
Threshold
VTH_LEDOPEN
15
25
40
mV
—
Open Detect Blanking Time
TBLANK_OPEN
—
65
—
µs
(Note 2)
Open Retry Time-out
TRETRY_OPEN
—
100
—
ms
(Note 2)
Short Trigger Threshold
VTH_LEDSHORT
400
600
800
mV
VOUT – MAX[VLED1,VLED2],
VOUT = 3.6V
Short Trigger Hysteresis
VHYST_LED-
—
200
—
mV
(Note 2)
Additional Protection Features
SHORT
Short Trigger Blanking Time
TBLANK_SHORT
—
30
—
µs
(Note 2)
Short Retry Time-out
TRETRY_SHORT
—
100
—
ms
(Note 2)
Note 1:
2:
Specification for packaged product only.
Specifications are obtained by design and characterization; not 100% tested in production.
2018 Microchip Technology Inc.
DS20006078A-page 7
MIC2870
TEMPERATURE SPECIFICATIONS (Note 1)
Parameters
Sym.
Min.
Typ.
Max.
Units
Conditions
Maximum Junction Temperature Range
TJ
–40
—
150
°C
—
Operating Junction Temperature
Range
TJ
–40
—
125
°C
—
Storage Temperature
TS
–40
—
150
°C
—
Lead Temperature
—
—
—
260
°C
Soldering, 10s
JA
—
+80
—
°C/W
Temperature Ranges
Package Thermal Resistance
Thermal Resistance 2 mm x 2 mm
TQFN-16LD
Note 1:
—
The maximum allowable power dissipation is a function of ambient temperature, the maximum allowable
junction temperature and the thermal resistance from junction to air (i.e., TA, TJ, JA). Exceeding the
maximum allowable power dissipation will cause the device operating junction temperature to exceed the
maximum +150°C rating. Sustained junction temperatures above +150°C can impact the device reliability.
DS20006078A-page 8
2018 Microchip Technology Inc.
MIC2870
2.0
TYPICAL PERFORMANCE CURVES
Note:
The graphs and tables provided following this note are a statistical summary based on a limited number of
samples and are provided for informational purposes only. The performance characteristics listed herein
are not tested or guaranteed. In some graphs or tables, the data presented may be outside the specified
operating range (e.g., outside specified power supply range) and therefore outside the warranted range.
TORCH MODE LED CURRENT (mA)
SHUTDOWN CURRENT (µA)
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0.0
-40
-20
0
20
40
60
80
100
120
190
189
188
187
TORCH MODE
L = 1µH
COUT = 2.2µF
ILED = 187.5mA
VLED = 890mV
RTRSET
10k
O
TRSET ==10k
186
185
-40
-20
TEMPERATURE (°C)
Shutdown Current vs.
QUIESCENT CURRENT (µA)
0.94
0.93
0.92
0.91
0.90
0.89
0.88
LINEAR MODE NOT SWITCHING
VLED1 = VLED2 > 200mV
0.87
-40
-20
0
20
40
60
80
40
60
80
100
120
100
120
850
800
750
700
FLASH MODE
L = 1µH
COUT = 2.2µF
ILED = 750mA
650
VLED = 890mV
RFRSET
10k
10k
O
FRSET= =
600
-40
-20
TEMPERATURE (°C)
0
20
40
60
80
100
120
TEMPERATURE (°C)
FIGURE 2-2:
Quiescent Current (Linear
Mode) vs. Temperature.
FIGURE 2-5:
Flash Mode LED1 and
LED2 Current vs. Temperature.
250
4.50
BOOST MODE SWITCHING
VLED1 = VLED2 = 70mV
4.45
TORCH MODE ILED(MAX) (mA)
QUIESCENT CURRENT (µA)
20
FIGURE 2-4:
Torch Mode LED1 and
LED2 Current vs. Temperature.
FLASH MODE LED CURRENT (mA)
FIGURE 2-1:
Temperature.
0
TEMPERATURE (°C)
4.40
4.35
4.30
4.25
4.20
4.15
4.10
-40
-20
0
20
40
60
80
100
120
TEMPERATURE (°C)
FIGURE 2-3:
Quiescent Current (Boost
Mode) vs. Temperature.
2018 Microchip Technology Inc.
L = 1 µH
COUT = 2.2µF
DUAL LEDs
200
ILED PER CHANNEL
TA = 25°C
150
100
50
0
0
10
20
30
40
50
60
70
80
TRSET RESISTOR
RESISTOR(k?
(k)
TRSET
)
FIGURE 2-6:
Torch Mode ILED(MAX) (Dual
LEDs) vs. TRSET Resistor.
DS20006078A-page 9
FLASH MODE ILED(MAX) (mA)
800
700
L = 1 µH
COUT = 2.2µF
DUAL LEDs
600
ILED PER CHANNEL
TA = 25°C
500
400
300
200
100
0
0
10
20
30
40
50
60
70
80
TORCH MODE ILED(MAX) ACCURACY (%)
MIC2870
2.5
82k
TRSET==82kO
75k RTRSET
RTRSET
TRSET ==75kO
2.0
RTRSET
62k
TRSET==62kO
51k
RTRSET
TRSET ==51kO
1.5
1.0
0.5
0.0
RTRSET
39k
TRSET ==39kO
30k
RTRSET
TRSET ==30kO
20k
RTRSET
TRSET ==20kO
-0.5
-1.0
10k
RTRSET
TRSET ==10kO
-1.5
-2.0
-2.5
3.5
3.7
FRSET RESISTOR (k)
FIGURE 2-7:
Flash Mode ILED(MAX) (Dual
LEDs) vs. FRSET Resistor.
4.3
2.20
SWITCHING FREQUENCY (MHz)
TORCH MODE ILED(MAX) (mA)
4.1
FIGURE 2-10:
Torch Mode ILED(MAX)
Accuracy vs. Input Voltage.
400
350
300
250
200
150
L = 1 µH
COUT = 2.2µF
SINGLE LED
ILED1+ILED2
100
50
TA = 25°C
0
-40°C
-40 C
2.15
25°C
25
C
2.10
2.05
2.00
75°C
75
C
1.95
125°C
125 C
1.90
L = 1 µH
COUT = 2.2µF
ILED1+ ILED2 = 1.5A
1.85
1.80
0
10
20
30
40
50
60
70
80
2.5
3.0
TRSET RESISTOR (k)
3.5
4.0
4.5
INPUT VOLTAGE (V)
FIGURE 2-8:
Torch Mode ILED(MAX)
(Single LED) vs. TRSET Resistor.
FIGURE 2-11:
vs. Input Voltage.
1600
Boost Switching Frequency
100
1400
90
1200
EFFICIENCY (%)
FLASH MODE ILED(MAX) (mA)
3.9
INPUT VOLTAGE (V)
1000
800
600
400
L = 1 µH
COUT = 2.2µF
SINGLE LED
200
ILED1+ILED2
TA = 25°C
80
ILED = 1.5A
ILED = 1.2A
70
ILED = 780mA
ILED = 375mA
60
0
L = 1µH
COUT = 2.2µF
25°C
C
TA = 25
50
0
10
20
30
40
50
60
70
FRSET RESISTOR (k)
FIGURE 2-9:
Flash Mode ILED(MAX)
(Single LED) vs. FRSET Resistor.
DS20006078A-page 10
80
2.6
3.0
ILED = 150mA
3.4
3.8
4.2
4.6
5.0
INPUT VOLTAGE (V)
FIGURE 2-12:
WLED Output Power
Efficiency vs. Input Voltage.
2018 Microchip Technology Inc.
MIC2870
q
(Linear Mode)
(Boost Mode)
VFEN
(5V/div)
VTEN
(5V/div)
VOUT
(2V/div)
VOUT
(2V/div)
VOUT – VLED
(2V/div)
VLED1/2
(1V/div)
VLED1/2
(2V/div)
VOUT – VLED
(2V/div)
ILED1 + ILED2 = 1.5A
VIN = 3.0V
L = 1μH
ILED1 + ILED2
(1A/div)
ILED1 + ILED2
(200mA/div)
Time (100μs/div)
ILED1 + ILED2 = 375mA
VIN = 4.2V
L = 1μH
Time (40μs/div)
FIGURE 2-13:
Flash Mode Turn-On
Sequence (Boost Mode).
FIGURE 2-16:
Torch Mode Turn-On
Sequence (Linear Mode).
q
(Linear Mode)
and Enable Off Blanking Time
VEN
(5V/div)
VFEN
(5V/div)
VOUT
(2V/div)
VOUT
(2V/div)
VLED1/2
(2V/div)
VLED1/2
(2V/div)
VOUT – VLED
(2V/div)
ILED1 + ILED2 = 1.5A
VIN = 4.2V
L = 1μH
ILED1 + ILED2
(1A/div)
ILED1 + ILED2
(1A/div)
Time (40μs/div)
FIGURE 2-14:
Flash Mode Turn-On
Sequence (Linear Mode).
ILED1 + ILED2 = 1.5A
VIN = 3.6V
L = 1μH
Time (200ms/div)
FIGURE 2-17:
Flash Mode Load
Disconnect and Enable Off Blanking Time.
(Boost Mode)
and Enable Off Blanking Time
VEN
(5V/div)
VTEN
(5V/div)
VOUT
(2V/div)
VOUT – VLED
(2V/div)
VLED1/2
(1V/div)
VOUT
(2V/div)
VLED1/2
(2V/div)
ILED1 + ILED2 = 375mA
VIN = 2.7V
L = 1μH
ILED1 + ILED2
(200mA/div)
Time (40μs/div)
FIGURE 2-15:
Torch Mode Turn-On
Sequence (Boost Mode).
2018 Microchip Technology Inc.
ILED1 + ILED2 = 375mA
VIN = 3.6V
L = 1μH
ILED1 + ILED2
(500mA/div)
Time (200ms/div)
FIGURE 2-18:
Torch Mode Load
Disconnect and Enable Off Blanking Time.
DS20006078A-page 11
MIC2870
VTEN
(5V/div)
LED1 AND LED2 OPEN CIRCUIT AFTER
TORCH/FLASH START
VOUT
(5V/div)
VOUT
(2V/div)
VLED1/2
(2V/div)
VLED1/2
(5V/div)
VOUT – VLED
(5V/div)
ILED1/2 = 70mA
VIN = 3.6V
L = 1μH
IL
(100mA/div)
VSW
(5V/div)
ILED1 + ILED2
(1A/div)
Time (20μs/div)
FIGURE 2-19:
Protection.
LED Open-Circuit
ILED + ILED2 = 1.5A
VIN = 3.6V
L = 1μH
Time (100μs/div)
FIGURE 2-22:
Recovery.
Overvoltage Protection
Recovery
VFEN
(5V/div)
VFI
(5V/div)
VTEN
(5V/div)
VOUT
(5V/div)
ILED1
(500mA/div)
VLED1/2
(5V/div)
FLASH ILED = 750mA
TORCH ILED = 187.5mA
VOUT – VLED
(10V/div)
IL
(1A/div)
ILED2
(500mA/div)
ILED1 + ILED2= 375mA
VIN = 3.6V, L = 1μH
Time (2ms/div)
FIGURE 2-20:
Recovery.
LED Open-Circuit Protection
VNIN==4.2V
4.2V
V
L = 1μH
Time (2ms/div)
FIGURE 2-23:
Flash Inhibit and Recovery.
Retry, and Recovery
VTEN
(5V/div)
VOUT
(2V/div)
VOUT
(2V/div)
VLED1/2
(2V/div)
VLED1/2
(2V/div)
VOUT – VLED
(2V/div)
VSW
(5V/div)
ILED1 + ILED2
(500mA/div)
OVP @ STARTUP
VIN = 3.6V
L = 1μH
5 RESISTOR IN SERIES WITH LED
Time (40μs/div)
FIGURE 2-21:
DS20006078A-page 12
Overvoltage Protection.
ILED1 + ILED2
(200mA/div)
ILED1 + ILED2 = 375mA
VIN = 4.2V
L = 1μH
Time (40ms/div)
FIGURE 2-24:
LED Short-Circuit
Protection, Retry and Recovery.
2018 Microchip Technology Inc.
MIC2870
VOUT
(1V/div)
VOUT
(1V/div)
VOUT – VLED
(2V/div)
VOUT – VLED
(2V/div)
VLED1/2
(1V/div)
VIN = 3.6V
L = 1μH
ILED1 + ILED2
(500mA/div)
VLED1/2
(1V/div)
ILED1 + ILED2
(500mA/div)
Time (200ms/div)
Time (200ms/div)
FIGURE 2-25:
1250 ms.
Flash Safety Timer @
2018 Microchip Technology Inc.
VIN = 3.6V
L = 1μH
FIGURE 2-26:
156 ms.
Flash Safety Timer @
DS20006078A-page 13
MIC2870
3.0
PIN DESCRIPTIONS
The descriptions of the pins are listed in Table 3-1.
TABLE 3-1:
PIN FUNCTION TABLE
MIC2870
Pin Number
Pin Name
1
SCL
High-Speed Mode (3.4 MHz) I2C Clock Input.
2
VIN
Supply Input: Connect a low-ESR ceramic capacitor of at least 4.7 µF to PGND. A small
capacitor of 100 nF between VIN and AGND is highly recommended.
3
FEN
Flash-Mode Enable Pin: A low-to-high transition initiates the Flash mode and Flash
mode timer. If FEN is left floating, it is pulled-down internally by a built-in 1 µA current
source when the device is enabled.
4
FI
Flash Inhibit: When FI is pulled high, both LED currents are changed from the Flash
mode current level to the Torch mode current level. If FI is left floating, it is pulled down
internally by a built-in 1 µA current source when the device is enabled. This function is
generally used to reduce instantaneous battery load current by synchronizing with the
handset’s GSM pulse off-time.
5
FRSET
Flash Mode Current-Level Programming: Connect a resistor from FRSET to AGND to
set the maximum current in the Flash mode. For example, a 10 k resistor sets the LED
sink current to its maximum value of 750 mA per channel. FRSET can be grounded if the
default maximum Flash mode current (750 mA) is desired. FRSET, however, cannot be
left floating and the maximum resistance is limited to 80 k.
Pin Function
6
AGND
Analog Ground: Reference ground for the FRSET and TRSET pins.
7, 15
PGND
Power Ground: PGND is used for the switching NMOS and PMOS of boost converter
and Power Ground for LED current sinks.
8
TRSET
Torch Mode Current Level Programming: Connect a resistor from TRSET to AGND to
set the maximum current in the Torch mode. For example, a 10 k resistor sets the LED
sink current to its maximum value of 187.5 mA per channel. TRSET can be grounded if
the default maximum Torch mode current (187.5 mA) is desired. TRSET, however,
cannot be left floating and the maximum resistance is limited to 80 k.
9
LED2
Channel 2 LED Current Sink: Connect the LED anode to OUT and the cathode to LED2.
10
LED1
Channel 1 LED Current Sink: Connect the LED anode to OUT and the cathode to LED1.
11
TEN
Torch Mode Enable: Initiates Torch mode when TEN is high. If TEN is left floating, it is
pulled down internally by a built-in 1 µA current source when the device is enabled.
12
OUT
13
EN
Enable (IC): The MIC2870 is in Standby mode when EN is asserted high. If EN is driven
low for more than 1s, the IC is shut down. Alternatively, the I2C interface can be used for
enabling/disabling the IC through the Master Control/Status register. EN is pulled down
by an internal resistor.
14
SW
Inductor Connection: It is connected to the internal power MOSFETs.
16
SDA
High-Speed Mode (3.4 MHz) I2C Data Input/Output.
EP
ePAD
Exposed Heat Sink Pad: Connect to PGND ground plane for best thermal performance.
This pin is internally connected to PGND.
DS20006078A-page 14
Boost Converter Output.
2018 Microchip Technology Inc.
MIC2870
4.0
FUNCTIONAL DESCRIPTION
4.1
VIN
The input supply provides power to the internal
MOSFETs’ gate drive and controls circuitry for the switch
mode regulator. The operating input voltage range is
from 2.7V to 5.0V. A 4.7 µF low-ESR ceramic input
capacitor should be connected from VIN to AGND, as
close to MIC2870 as possible to ensure a clean supply
voltage for the device. The minimum voltage rating of
10V is recommended for the input capacitor.
4.2
SW
The MIC2870 has internal low-side and synchronous
MOSFET switches. The switch node (SW), between the
internal MOSFET switches, connects directly to one end
of the inductor and provides the current paths during
switching cycles. The other end of the inductor is connected to the input supply voltage. Due to the
high-speed switching on this pin, the switch node should
be routed away from sensitive nodes wherever possible.
4.3
AGND
This is the ground path for the internal biasing and control
circuitry. The current loop of the Analog Ground should be
separated from that of the Power Ground (PGND). AGND
should be connected to PGND at a single point.
4.4
PGND
The Power Ground pin is the ground path for the high
current in the boost switch and the ground path of the
LED current sinks. The current loop for the Power
Ground should be as small as possible and separate
from the AGND loop as applicable.
4.5
OUT
OUT is the boost converter output pin, which is connected to the anode of the LED. A low-ESR ceramic
capacitor of 2.2 µF or larger should be connected from
OUT to PGND, as close as possible to the MIC2870.
The minimum voltage rating of 10V is recommended for
the output capacitor.
4.6
LED1/LED2
These are the current sink pins for the LED(s). The LED
anode is connected to the OUT pin and the LED cathode
is connected to the LED1/LED2 pin(s).
4.7
EN
This is the enable pin of the MIC2870. The MIC2870 is in
Standby mode when the EN pin is asserted high. If this pin
is driven low for more than one second, the IC is shut
down. Alternatively, the I2C interface can be used for
2018 Microchip Technology Inc.
enabling/disabling the IC through the Master
Control/Status register. EN is pulled down by an internal
resistor.
4.8
FEN
FEN is the hardware enable pin for Flash mode. A logic
low-to-high transition on the FEN pin initiates the Flash
mode. If the FEN pin is left floating, it is pulled down internally by a built-in 1 µA current source when the device is
enabled. Flash mode is terminated when FEN is pulled
low or left floating, and the Flash Control register is
cleared.
4.9
TEN
TEN is the hardware enable pin for Torch mode. A logic
low-to-high transition on the TEN pin initiates the Torch
mode. If the TEN pin is left floating, it is pulled down internally by a built-in 1 µA current source when the device is
enabled. Torch mode is terminated when TEN is pulled
low or left floating, and the Torch Control register is
cleared.
4.10
FI
FI is the Flash Inhibit pin. When this pin is high in Flash
mode, both the LED1 and LED2 currents are changed
from the Flash mode current level to the Torch mode current level. When this pin is low, both the LED1 and LED2
currents are changed from the Torch mode current level
back to the original Flash mode current level.
4.11
FRSET
The Flash mode maximum LED current level is programmed through the FRSET pin. A resistor connected
from FRSET to AGND sets the maximum current in the
Flash mode. FRSET can be grounded for the default
Flash mode current of 0.75A. For best current accuracy,
a 0.1% tolerance resistor is recommended. FRSET
cannot be left floating and the maximum resistance is
limited to 80 k.
4.12
TRSET
The Torch mode maximum LED current level is programmed through the TRSET pin. A resistor connected
from the TRSET pin to AGND sets the maximum current
in the Torch mode. TRSET can be grounded for the
default torch mode current of 187.5 mA. For best current
accuracy, a 0.1% tolerance resistor is recommended.
TRSET cannot be left floating and the maximum
resistance is limited to 80 k.
4.13
SCL
I2C
The
clock input pin provides a reference clock for
clocking in the data signal. This is a high-speed mode, up
to 3.4 MHz, input pin and requires a 4.7 k pull-up resistor.
DS20006078A-page 15
MIC2870
4.14
SDA
The I2C data input/output pin allows for data to be
written to and read from the MIC2870. This is a
high-speed mode, up to 3.4 MHz, I2C pin and requires
a 4.7 k pull-up resistor.
DS20006078A-page 16
2018 Microchip Technology Inc.
MIC2870
5.0
APPLICATION INFORMATION
The MIC2870 can drive one or two high-current Flash
WLEDs in either Flash mode or Torch mode. Two WLEDs
can be used to optimize the light output and beam shaping through the optical lens/reflector assembly. In this
case, the two channels, up to 750 mA each, are matched
to within 10% for optimal Flash illumination. When the two
channels are combined to drive a single high-brightness
WLED, the maximum current is 1.5A. If one of the channels is left floating, MIC2870 senses the circuit condition
automatically and allows the other channel to operate.
5.1
Flash Mode
The maximum current level in the Flash mode is
750 mA per channel. This current level can be adjusted
through an external resistor connected to FRSET,
according to the following equation:
EQUATION 5-1:
ADJUSTING FLASH
MODE CURRENT LEVEL
ILED(MAX) =
7500
RFRSET
Alternatively, the default maximum value of 750 mA per
channel is used when FRSET is grounded.
The Flash mode current can be initiated at the preset
FRSET brightness level by asserting FEN high or by
setting the I2C Flash Control register (address: 01h) for
the desired Flash duration, subjected to the Flash
safety time-out setting. The Flash mode current is
terminated when FEN is brought low and the I2C Flash
register is cleared.
The Flash Inhibit (FI) pin can be used to synchronize
the Flash current to a handset GSM pulse event to
prevent excessive battery droop. When the FEN and FI
pins are both high, the Flash mode current is limited to
the Torch mode current setting. The FI pin is also functional when the Flash mode current is enabled through
the I2C Flash register.
Flash mode current can be adjusted to a fraction of the
maximum Flash mode level (either default or set by the
FRSET resistor) by selecting the desired Flash current
level percentage in the Flash Control register
(address: 01h) through the I2C interface. The Flash
current is the product of the maximum Flash current
setting and the percentage selected in the Flash register.
5.2
Torch Mode
The maximum Torch mode current level can be
adjusted through an external resistor connected to the
TRSET pin, according to Equation 5-2:
EQUATION 5-2:
ADJUSTING TORCH
MODE CURRENT LEVEL
ILED(MAX) =
7500
4RTRSET
Alternatively, the default maximum value of 187.5 mA
per channel is used when the TRSET pin is grounded.
The Torch mode operation is activated by asserting
TEN high or by setting the I2C Torch register
(address: 02h) for the desired duration. The Torch
mode current is terminated when TEN is brought low
and the I2C Torch register is cleared.
Like the Flash mode current, the Torch mode current
can be set to a fraction of the maximum Torch mode
level (either default or set by the TRSET resistor) by
selecting the desired torch current level percentage in
the Torch register (address: 02h) through the I2C interface. The torch current is the product of the maximum
torch current setting and the percentage selected in the
Torch register.
5.3
Overvoltage Protection
When the output voltage rises above the overvoltage
protection (OVP) threshold, the MIC2870 is turned off
automatically to avoid permanent damage to the IC.
5.4
Open-Circuit Detection
The Open-Circuit Detector (OCD) is active only when
the LED current regulator is turned on. When the external LED is missing or fails open, the LED1/2 pin voltage
is pulled to near the ground potential by the internal
current sink. If both LEDs are open or missing, the
Open-Circuit Detector would force the boost regulator
and LED current regulator to turn off. The MIC2870 will
try to turn on the boost regulator and LED current
regulator again after a 100 ms time-out. However, in
most practical cases, the boost output voltage would
rise above the OVP threshold when both LED channels
have an open Fault. The OVP function would cause the
MIC2870 to shut down.
The Flash safety time-out feature automatically shuts
down the Flash current if the Flash mode is enabled for
an extended period of time. Refer to the Flash safety
timer setting in Table 5-4.
2018 Microchip Technology Inc.
DS20006078A-page 17
MIC2870
5.5
Short-Circuit Detection
5.7
Like the OCD, the short-circuit detector is active only
when the current regulator is turned on. If either one or
both of the external LEDs fail a short, the short-circuit
detector would force the MIC2870 to turn off. The
MIC2870 will try to turn on the boost regulator and LED
current regulator again after a 100 ms time-out. If the
short condition persists, the whole cycle repeats again.
Prolonged operation in short-circuit condition is not
recommended as it can damage the device.
Figure 5-1 shows the communications required for
write and read operations via the I2C interface. The
black lines show master communications and the red
lines show the slave communications. During a write
operation, the master must drive SDA and SCL for all
stages, except the Acknowledgment (A) shown in red,
which is provided by the slave (MIC2870):
SLAVE
ADDRESS
MIC2870 contains three 8-bit Read/Write registers,
having an address from 00h to 02h for operation control, as shown in Table 5-1. These registers are reset to
their default values in a Power-on Reset (POR) event.
In other words, they hold their previous contents when
the chip is shut down as long as supply voltage is
above 1.5V (typical).
TABLE 5-1:
Register
Address
I2C Interface
5.6
REGISTER
ADDRESS
SCL
A
W A
A
REGISTER
ADDRESS
P
SLAVE
ADDRESS
DATA
SDA
SCL
S
A
WA
FIGURE 5-1:
Register
Name
Description
00h
Master
Chip Enable Control and
Control/Status Status register
01h
Flash Control Flash Mode Current, Flash
Mode Enable and Flash
Time-out Control register
02h
Torch Control Torch Mode Current and
Torch Mode Enable
Control register
5.8
SLAVE
ADDRESS
MIC2870 REGISTER MAP
DATA
SDA
S
I2C Registers
Sr
R A
A
P
2
I C Timing Example.
Master Control/Status Register
(00h)
The Master Control/Status register allows the MIC2870
to be enabled by the I2C interface – setting the ON[ ] bit
high has the same effect as asserting the EN pin. The
LED Short bit, LED_SHT[ ], is set if any or both of the
LEDs is shorted to OUT, while the LED Open bit,
LED_OP[ ], is asserted only when both LEDs are open
circuit. The Thermal Shutdown bit, TSD[ ], is set when
the junction temperature of the MIC2870 is higher than
+160°C.
5.9
Flash Control Register (01h)
The read operation begins with a dataless write to
select the register address from which to read. Then, a
restart sequence is issued and then a read command
followed by the data read.
The Flash safety timer and Flash mode current are
configurable via the Flash Control register. Refer to the
Flash time-out duration setting and Flash mode current
setting in Table 5-4 and Table 5-5.
The MIC2870 responds to a slave address of Hex: 0xB4
and 0xB5 for write and read operations, respectively, or
binary ‘1011010x’ (where ‘x’ is the read/write bit).
5.10
The register address is eight bits wide and carries the
address of the MIC2870 register to be operated upon.
Only the lower three bits are used.
DS20006078A-page 18
Torch Control Register (02h)
The Torch mode current is configurable via the Torch
Control register. Refer to the Torch mode current
setting in Table 5-7. The FI[ ] bit has the same function
as the FI pin. When the FI[ ] bit is set, the Flash mode
current is reduced to the Torch mode current setting.
2018 Microchip Technology Inc.
MIC2870
TABLE 5-2:
Bit
MASTER CONTROL REGISTER (00h)
D7
D6
D5
Name
Reserved
Access
R
D4
Bit
D2
D1
D0
ON
LED_SHT
LED_OP
TSD
R/W
Default Value
TABLE 5-3:
D3
R
0
FLASH CONTROL REGISTER (01h)
D7
D6
Name
D5
FTMR
D4
D3
FEN
Access
D2
D1
D0
FCUR
R/W
Default Value
TABLE 5-4:
TABLE 5-5:
111
0
0000
FLASH SAFETY TIMER SETTING (FTMR)
Register Value (D)
Flash Time-out Duration (ms)
111
1250
110
1093.75
101
937.5
100
781.25
011
625
010
468.75
001
312.5
000
156.25
FLASH MODE CURRENT SETTING (FCUR)
Percentage of Maximum
Current (%)
Register Value
(D) of 01h
Current per Channel (mA)
(RFRSET = 0)
Combined Current (mA)
(RFRSET = 0)
100
0000
750.0
1500.0
90
0001
675.0
1350.0
80
0010
600.0
1200.0
70
0011
525.0
1050.0
63
0100
472.5
945.0
56
0101
420.0
840.0
50
0110
375.0
750.0
44.7
0111
335.3
670.5
39.8
1000
298.5
597.0
35.5
1001
266.3
532.5
31.6
1010
237.0
474.0
28.2
1011
211.5
423.0
25.1
1100
188.3
376.5
22.4
1101
168.0
336.0
20
1110
150.0
300.0
18
1111
135.0
270.0
2018 Microchip Technology Inc.
DS20006078A-page 19
MIC2870
TABLE 5-6:
TORCH CONTROL REGISTER (02h)
Bit
D7
D6
Name
Reserved
Access
RO
Default Value
TABLE 5-7:
D5
D4
FI
TEN
D3
D2
D1
D0
TCUR
R/W
0
0000
TORCH MODE CURRENT SETTING (TCUR)
Percentage of Maximum
Current (%)
Register Value
(D) of 02h
Current per Channel (mA)
(RTRSET = 0)
Combined Current (mA)
(RTRSET = 0)
100
0000
187.5
375.0
90
0001
168.8
337.5
80
0010
150.0
300.0
70
0011
131.3
262.5
63
0100
118.1
236.3
56
0101
105.0
210.0
50
0110
93.8
187.5
44.7
0111
83.8
167.6
39.8
1000
74.6
149.3
35.5
1001
66.6
133.1
31.6
1010
59.3
118.5
28.2
1011
52.9
105.8
25.1
1100
47.1
94.1
22.4
1101
42.0
84.0
20
1110
37.5
75.0
18
1111
33.8
67.5
DS20006078A-page 20
2018 Microchip Technology Inc.
MIC2870
6.0
COMPONENT SELECTION
6.1
Inductor
Inductor selection is a balance between efficiency,
stability, cost, size, and rated current. Because the
boost converter is compensated internally, the recommended inductance of L is limited from 1 µH to 2.2 µH
to ensure system stability. It is usually a good balance
between these considerations.
A large inductance value reduces the peak-to-peak
inductor ripple current; hence, the output ripple voltage
and the LED ripple current. This also reduces both the
DC loss and the transition loss at the same inductor’s
DC Resistance (DCR). However, the DCR of an inductor
usually increases with the inductance in the same package size. This is due to the longer windings required for
an increase in inductance. Because the majority of the
input current passes through the inductor, the higher the
DCR, the lower the efficiency is, and more significantly,
at higher load currents. On the other hand, an inductor
with smaller DCR, but the same inductance, usually has
a larger size. The saturation current rating of the
selected inductor must be higher than the maximum
peak inductor current to be encountered and should be
at least 20% to 30% higher than the average inductor
current at maximum output current.
6.2
6.3
Output Capacitor
Output capacitor selection is also a trade-off between
performance, size and cost. Increasing the output
capacitor will lead to an improved transient response,
however, the size and cost will also increase. The output capacitor is preferred in the range of 2.2 µF to
10 µF with ESR from 10 m to 50 m. X5R or X7R
type ceramic capacitors are recommended for better
tolerance over temperature.
The Y5V and Z5U type ceramic capacitors are not recommended due to their wide variation in capacitance
over temperature and increased resistance at high frequencies. The rated voltage of the output capacitor
should be at least 20% higher than the maximum operating output voltage over the operating temperature
range.
6.4
FRSET/TRSET Resistor
Because the FRSET/TRSET resistor is used for setting
the maximum LED current in Flash mode and Torch
mode, respectively, a resistor type with 0.1% tolerance
is recommended for more accurate LED current
setting.
Input Capacitor
A ceramic capacitor of 4.7 µF or larger with low-ESR is
recommended to reduce the input voltage ripple to
ensure a clean supply voltage for the device. The input
capacitor should be placed as close as possible to the
MIC2870 VIN pin, with a short trace for good noise
performance. X5R or X7R type ceramic capacitors are
recommended for better tolerance over temperature.
The Y5V and Z5U type temperature rating ceramic
capacitors are not recommended due to their large
reduction in capacitance over temperature and
increased resistance at high frequencies. These
reduce their ability to filter out high-frequency noise.
The rated voltage of the input capacitor should be at
least 20% higher than the maximum operating input
voltage over the operating temperature range.
2018 Microchip Technology Inc.
DS20006078A-page 21
MIC2870
7.0
POWER DISSIPATION
CONSIDERATION
As can be seen in the diagram, the total thermal
resistance: JA = JC + CA. Hence, this can also be
written as in Equation 7-3:
As with all power devices, the ultimate current rating of
the output is limited by the thermal properties of the
device package and the PCB on which the device is
mounted. There is a simple, Ohm’s law type relationship between thermal resistance, power dissipation
and temperature, which are analogous to an electrical
circuit:
RXY
VX
VY
RYZ
EQUATION 7-3:
TJ = PDISS (JA) + TA
Where:
θJA = Thermal resistance between junction and ambient,
which is typically 80°C/W for 2 x 2 TQFN package
VZ
ISOURCE
VZ
Because, all of the power losses (minus the inductor
losses) in the converter are dissipated within the
MIC2870 package, PDISS can be calculated thus:
EQUATION 7-4:
FIGURE 7-1:
Circuit.
Series Electrical Resistance
CALCULATING PDISS
Linear Mode: PDISS = [POUT – 1 ] – IOUT2 DCR
From this simple circuit, we can calculate VX if we know
the ISOURCE, VZ and the resistor values, RXY and RYZ,
using Equation 7-1:
IOUT 2
Boost Mode: PDISS = [POUT – 1 ] –
DCR
1 – D
EQUATION 7-1:
Duty Cycle in Boost Mode: D =
CALCULATING VX
VX = ISOURCE (RXY + RYZ) + VZ
Thermal circuits can be considered using this same
rule and can be drawn similarly by replacing current
sources with power dissipation (in watts), resistance
with thermal resistance (in °C/W) and voltage sources
with temperature (in °C).
TJCJC
TJ
TC
TCA
CA
PDISS
FIGURE 7-2:
Circuit.
VOUT – VIN
VOUT
Where:
= Efficiency taken from efficiency curves
DCR = Inductor DCR
TA
TA
Series Thermal Resistance
Now replacing the variables in the equation for VX, we
can find the Junction Temperature (TJ) from the power
dissipation, ambient temperature, and the known thermal
resistance of the PCB (CA) and the package (JC).
EQUATION 7-2:
JUNCTION TEMPERATURE
TJ = PDISS (JC + CA) + TA
DS20006078A-page 22
2018 Microchip Technology Inc.
MIC2870
Where the real board area differs from 1" square, CA
(the PCB thermal resistance) values for various PCB
copper areas can be taken from Figure 7-3. Figure 7-3
is taken from “Designing with Low Dropout Voltage
Regulators” available from the Microchip web site
(www.microchip.com).
Figure 7-3 shows the total area of a round or square pad,
centered on the device. The solid trace represents the
area of a square single-sided, horizontal, solder masked,
copper PC board trace heat sink, measured in square
millimeters. No airflow is assumed. The dashed line
shows the PC board’s trace heat sink, covered in black
oil-based paint, and with 1.3m/sec (250 feet per minute)
airflow. This approaches a “best case” pad heat sink.
Conservative design dictates using the solid trace data,
which indicates that a maximum pad size of 5000 mm2 is
needed. This is a pad that is 71 mm x 71 mm (2.8 inches
per side).
FIGURE 7-3:
Graph to Determine PC
Board Area for a Given PCB Thermal Resistance.
2018 Microchip Technology Inc.
DS20006078A-page 23
MIC2870
8.0
PCB LAYOUT GUIDELINES
PCB layout is critical to achieve reliable, stable and efficient performance. A ground plane is required to control
EMI and minimize the inductance in power and signal
return paths. The following guidelines should be followed
to ensure proper operation of the device:
8.1
IC (Integrated Circuit)
• Place the IC close to the point-of-load (in this
case, the flash LED).
• Use fat traces to route the input and output power
lines.
• Analog ground (AGND) and power ground
(PGND) should be kept separate and connected
at a single location.
• The exposed pad (ePad) on the bottom of the IC
must be connected to the PGND ground plane of
the PCB.
• 4 to 6 thermal vias must be placed on the PCB
pad for exposed pad and connected it to the
PGND ground plane to ensure a good PCB
thermal resistance can be achieved.
8.2
8.4
Output Capacitor
• Use wide and short traces to connect the output
capacitor to the OUT and PGND pins.
• Place several vias to the ground plane close to
the output capacitor ground terminal.
• Use either X5R or X7R temperature rating
ceramic capacitors. Do not use Y5V or Z5U type
ceramic capacitors.
8.5
Flash LED
• Use wide and short trace to connect the LED
anode to the OUT pin.
• Use wide and short trace to connect the LED
cathode to the LED1/LED2 pins.
• Make sure that the LED’s PCB land pattern can
provide sufficient PCB pad heat sink to the flash
LED.
8.6
FRSET/TRSET Resistor
• The FRSET/TRSET resistor should be placed
close to the FRSET/TRSET pin and connected to
AGND.
VIN Decoupling Capacitor
• The VIN decoupling capacitor must be placed
close to the VIN pin of the IC and preferably
connected directly to the pin and not through any
via. The capacitor must be located right at the IC.
• The VIN decoupling capacitor should be
connected to analog ground (AGND).
• The VIN terminal is noise sensitive and the
placement of capacitor is very critical.
8.3
Inductor
• Keep both the inductor connections to the switch
node (SW) and input power line short and wide
enough to handle the switching current. Keep the
areas of the switching current loops small to
minimize the EMI problem.
• Do not route any digital lines underneath or close
to the inductor.
• Keep the switch node (SW) away from the noise
sensitive pins.
• To minimize noise, place a ground plane
underneath the inductor.
DS20006078A-page 24
2018 Microchip Technology Inc.
MIC2870
9.0
PACKAGING INFORMATION
9.1
Package Marking Information
16-Lead TQFN*
Ÿ
Ÿ
XXX
NNN
Legend: XX...X
Y
YY
WW
NNN
e3
*
Example
70H
408
Product code or customer-specific information
Year code (last digit of calendar year)
Year code (last 2 digits of calendar year)
Week code (week of January 1 is week ‘01’)
Alphanumeric traceability code
Pb-free JEDEC® designator for Matte Tin (Sn)
This package is Pb-free. The Pb-free JEDEC designator ( e3 )
can be found on the outer packaging for this package.
●, ▲, ▼ Pin one index is identified by a dot, delta up or delta down (triangle
mark).
Note:
In the event the full Microchip part number cannot be marked on one line, it will
be carried over to the next line, thus limiting the number of available
characters for customer-specific information. Package may or may not include
the corporate logo.
Underbar (_) and/or Overbar (‾) symbol may not be to scale.
2018 Microchip Technology Inc.
DS20006078A-page 25
MIC2870
9.2
Package Details
The following sections give the technical details of the packages.
Note:
For the most current package drawings, please see the Microchip Packaging Specification located at
http://www.microchip.com/packaging.
DS20006078A-page 26
2018 Microchip Technology Inc.
MIC2870
Note:
For the most current package drawings, please see the Microchip Packaging Specification located at
http://www.microchip.com/packaging.
2018 Microchip Technology Inc.
DS20006078A-page 27
MIC2870
NOTES:
DS20006078A-page 28
2018 Microchip Technology Inc.
MIC2870
APPENDIX A:
REVISION HISTORY
Revision A (October 2018)
• Converted Micrel document MIC2870 to
Microchip data sheet DS20006078A.
• Minor text changes throughout document.
2018 Microchip Technology Inc.
DS20006078A-page 29
MIC2870
NOTES:
DS20006078A-page 30
2018 Microchip Technology Inc.
MIC2870
PRODUCT IDENTIFICATION SYSTEM
To order or obtain information, e.g., on pricing or delivery, contact your local Microchip representative or sales office.
PART NO.
Device
XX
X
–
Temperature Package
XX
Examples:
a)
MIC2870YFT-T5:
MIC2870,
-40°C to +125°C Temp. Range,
16-Pin TQFN, 500/Reel
b)
MIC2870YFT-TR:
MIC2870,
-40°C to +125°C Temp. Range,
16-Pin TQFN, 5,000/Reel
Media
Type
Device:
MIC2870:
1.5A Synchronous Boost Flash LED Driver
with I2C Interface
Temperature:
Y
=
-40°C to +125°C
Package:
FT
=
16-Pin 2 mm x 2 mm TQFN
Media Type:
T5
TR
=
=
500/Reel
5,000/Reel
2018 Microchip Technology Inc.
Note 1:
Tape and Reel identifier only appears in the
catalog part number description. This identifier is
used for ordering purposes and is not printed on
the device package. Check with your Microchip
Sales Office for package availability with the
Tape and Reel option.
DS20006078A-page 31
MIC2870
NOTES:
DS20006078A-page 32
2018 Microchip Technology Inc.
Note the following details of the code protection feature on Microchip devices:
•
Microchip products meet the specification contained in their particular Microchip Data Sheet.
•
Microchip believes that its family of products is one of the most secure families of its kind on the market today, when used in the
intended manner and under normal conditions.
•
There are dishonest and possibly illegal methods used to breach the code protection feature. All of these methods, to our
knowledge, require using the Microchip products in a manner outside the operating specifications contained in Microchip’s Data
Sheets. Most likely, the person doing so is engaged in theft of intellectual property.
•
Microchip is willing to work with the customer who is concerned about the integrity of their code.
•
Neither Microchip nor any other semiconductor manufacturer can guarantee the security of their code. Code protection does not
mean that we are guaranteeing the product as “unbreakable.”
Code protection is constantly evolving. We at Microchip are committed to continuously improving the code protection features of our
products. Attempts to break Microchip’s code protection feature may be a violation of the Digital Millennium Copyright Act. If such acts
allow unauthorized access to your software or other copyrighted work, you may have a right to sue for relief under that Act.
Information contained in this publication regarding device
applications and the like is provided only for your convenience
and may be superseded by updates. It is your responsibility to
ensure that your application meets with your specifications.
MICROCHIP MAKES NO REPRESENTATIONS OR
WARRANTIES OF ANY KIND WHETHER EXPRESS OR
IMPLIED, WRITTEN OR ORAL, STATUTORY OR
OTHERWISE, RELATED TO THE INFORMATION,
INCLUDING BUT NOT LIMITED TO ITS CONDITION,
QUALITY, PERFORMANCE, MERCHANTABILITY OR
FITNESS FOR PURPOSE. Microchip disclaims all liability
arising from this information and its use. Use of Microchip
devices in life support and/or safety applications is entirely at
the buyer’s risk, and the buyer agrees to defend, indemnify and
hold harmless Microchip from any and all damages, claims,
suits, or expenses resulting from such use. No licenses are
conveyed, implicitly or otherwise, under any Microchip
intellectual property rights unless otherwise stated.
Trademarks
Microchip received ISO/TS-16949:2009 certification for its worldwide
headquarters, design and wafer fabrication facilities in Chandler and
Tempe, Arizona; Gresham, Oregon and design centers in California
and India. The Company’s quality system processes and procedures
are for its PIC® MCUs and dsPIC® DSCs, KEELOQ® code hopping
devices, Serial EEPROMs, microperipherals, nonvolatile memory and
analog products. In addition, Microchip’s quality system for the design
and manufacture of development systems is ISO 9001:2000 certified.
SQTP is a service mark of Microchip Technology Incorporated in
the U.S.A.
QUALITY MANAGEMENT SYSTEM
CERTIFIED BY DNV
The Microchip name and logo, the Microchip logo, AnyRate, AVR,
AVR logo, AVR Freaks, BitCloud, chipKIT, chipKIT logo,
CryptoMemory, CryptoRF, dsPIC, FlashFlex, flexPWR, Heldo,
JukeBlox, KeeLoq, Kleer, LANCheck, LINK MD, maXStylus,
maXTouch, MediaLB, megaAVR, MOST, MOST logo, MPLAB,
OptoLyzer, PIC, picoPower, PICSTART, PIC32 logo, Prochip
Designer, QTouch, SAM-BA, SpyNIC, SST, SST Logo,
SuperFlash, tinyAVR, UNI/O, and XMEGA are registered
trademarks of Microchip Technology Incorporated in the U.S.A.
and other countries.
ClockWorks, The Embedded Control Solutions Company,
EtherSynch, Hyper Speed Control, HyperLight Load, IntelliMOS,
mTouch, Precision Edge, and Quiet-Wire are registered
trademarks of Microchip Technology Incorporated in the U.S.A.
Adjacent Key Suppression, AKS, Analog-for-the-Digital Age, Any
Capacitor, AnyIn, AnyOut, BodyCom, CodeGuard,
CryptoAuthentication, CryptoAutomotive, CryptoCompanion,
CryptoController, dsPICDEM, dsPICDEM.net, Dynamic Average
Matching, DAM, ECAN, EtherGREEN, In-Circuit Serial
Programming, ICSP, INICnet, Inter-Chip Connectivity,
JitterBlocker, KleerNet, KleerNet logo, memBrain, Mindi, MiWi,
motorBench, MPASM, MPF, MPLAB Certified logo, MPLIB,
MPLINK, MultiTRAK, NetDetach, Omniscient Code Generation,
PICDEM, PICDEM.net, PICkit, PICtail, PowerSmart, PureSilicon,
QMatrix, REAL ICE, Ripple Blocker, SAM-ICE, Serial Quad I/O,
SMART-I.S., SQI, SuperSwitcher, SuperSwitcher II, Total
Endurance, TSHARC, USBCheck, VariSense, ViewSpan,
WiperLock, Wireless DNA, and ZENA are trademarks of
Microchip Technology Incorporated in the U.S.A. and other
countries.
Silicon Storage Technology is a registered trademark of Microchip
Technology Inc. in other countries.
GestIC is a registered trademark of Microchip Technology
Germany II GmbH & Co. KG, a subsidiary of Microchip
Technology Inc., in other countries.
All other trademarks mentioned herein are property of their
respective companies.
© 2018, Microchip Technology Incorporated, All Rights Reserved.
ISBN: 978-1-5224-3690-4
== ISO/TS 16949 ==
2018 Microchip Technology Inc.
DS20006078A-page 33
Worldwide Sales and Service
AMERICAS
ASIA/PACIFIC
ASIA/PACIFIC
EUROPE
Corporate Office
2355 West Chandler Blvd.
Chandler, AZ 85224-6199
Tel: 480-792-7200
Fax: 480-792-7277
Technical Support:
http://www.microchip.com/
support
Web Address:
www.microchip.com
Australia - Sydney
Tel: 61-2-9868-6733
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Tel: 91-80-3090-4444
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Tel: 86-10-8569-7000
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Tel: 91-11-4160-8631
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Tel: 43-7242-2244-39
Fax: 43-7242-2244-393
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Tel: 86-28-8665-5511
India - Pune
Tel: 91-20-4121-0141
Denmark - Copenhagen
Tel: 45-4450-2828
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Tel: 631-435-6000
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Tel: 408-436-4270
Canada - Toronto
Tel: 905-695-1980
Fax: 905-695-2078
DS20006078A-page 34
China - Xiamen
Tel: 86-592-2388138
China - Zhuhai
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Tel: 47-7288-4388
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Tel: 48-22-3325737
Romania - Bucharest
Tel: 40-21-407-87-50
Spain - Madrid
Tel: 34-91-708-08-90
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Tel: 46-31-704-60-40
Sweden - Stockholm
Tel: 46-8-5090-4654
UK - Wokingham
Tel: 44-118-921-5800
Fax: 44-118-921-5820
2018 Microchip Technology Inc.
08/15/18
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