End of Life. Last Available Purchase Date is 31-Dec-2014
Si9136
Vishay Siliconix
Multi-Output Power-Supply Controller
DESCRIPTION
FEATURES
The Si9136 is a current-mode PWM and PSM converter
controller, with two synchronous buck converters (3.3 V and
5 V) and a flyback (non-isolated buck-boost) converter
(12 V). Designed for portable devices, it offers a total five
power outputs (three tightly regulated dc/dc converter
outputs, a precision 3.3 V reference and a 5 V LDO output).
It requires minimum external components and is capable of
achieving conversion efficiencies approaching 95 %.
The Si9136 is available in a 28-pin SSOP package and
specified to operate over the extended commercial (0 °C to
90 °C) temperature range.
•
•
•
•
•
•
•
•
•
•
•
•
•
Up to 95 % Efficiency
3 % Total Regulation (Each Controller)
5.5 V to 30 V Input Voltage Range
3.3 V, 5 V, and 12 V Outputs
200 kHz Low-Noise Fixed Frequency Operation
Precision 3.3 V Reference Output
30 mA Linear Regulator Output
High Efficiency Pulse Skipping Mode Operation at
Light Load
Only Three Inductors Required - No Transformer
LITTLE FOOT® Optimized Output Drivers
Internal Soft-Start
Minimal External Control Components
28-Pin SSOP Package
FUNCTIONAL BLOCK DIAGRAM
VIN
VL
(5.0 V)
5V
Linear
Regulator
3.3 V
Voltage
Reference
+ 3.3 V
3.3 V
SMPS
5V
SMPS
12 V SMPS
Control
Inputs
Document Number: 70818
S11-0975-Rev. D, 16-May-11
VREF
(+ 3.3 V)
+5V
+ 12 V
Power-Up Control
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End of Life. Last Available Purchase Date is 31-Dec-2014
Si9136
Vishay Siliconix
ABSOLUTE MAXIMUM RATINGS
Parameter
VIN to GND
PGND to GND
VL to GND
BST3, BST5, BSTFY to GND
VL Short to GND
LX3 to BST3; LX5 to BST5; LXFY to BST
Inputs/Outputs to GND (CS3, CS5, CSP, CSN)
5 ON/OFF, 3 ON/OFF, 12 ON/OFF
DL3, DL5 to PGND
DLFY to PGND
DH3 to LX3, DH5 to LX5, DHFY to LXFY
°C)a
b
28-Pin SSOP
Continuous Power Dissipation (TA = 90
Operating Temperature Range
Storage Temperature Range
Lead Temperature (Soldering, 10 Sec.)
Notes:
a. Device Mounted with all leads soldered or welded to PC board.
b. Derate 9.25 mW/°C above 90 °C.
Limit
- 0.3 to + 36 V
±2
- 0.3 to + 6.5 V
- 0.3 V to + 36 V
Continuous
- 6.5 V to 0.3 V
- 0.3 V to (VL + 0.3 V)
- 0.3 V to + 5.5 V
- 0.3 V to (VL + 0.3 V)
Input of Flyback
- 0.3 V to (BSTX + 0.3 V)
572
0 °C to 90 °C
- 40 °C to 125 °C
300
Unit
V
V
V
mW
°C
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation
of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum
rating conditions for extended periods may affect device reliability.
SPECIFICATIONS
Parameter
3.3 V Buck Controller
Total Regulation (Line, Load, and Temperature)
Line Regulation
Load Regulation
Current Limit
Bandwidth
Phase Margin
5 V Buck Controller
Total Regulation (Line, Load, and Temperature)
Line Regulation
Load Regulation
Current Limit
Bandwidth
Phase Margin
12 V Flyback Controller
Total Regulation (Line, Load, and Temperature)
Line Regulation
Load Regulation
Current Limit
Bandwidth
Phase Margin
Internal Regulator
VL Output
VL Fault Lockout Voltage
VL Fault Lockout Hysteresis
VL /FB5 Switchover Voltage
VL /FB5 Switchover Hysteresis
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Specific Test Conditions
VIN = 15 V , IVL = IREF = 0 mA
TA = 0 °C to 90 °C, All Converters ON
Limits
Min.
a
Typ.b
Max.a
3.33
3.43
± 0.5
± 0.5
160
VIN = 6 to 30 V, 0 < VCS3 - VFB3 < 90 mV
VIN = 6 to 30 V
0 < VCS3 - VFB3 < 90 mV
VCS3 - VFB3
L = 10 µH, C = 330 µF
RSENSE = 20 m
3.23
90
125
50
65
VIN = 6 to 30 V, 0 < VCS5 - VFB5 < 90 mV
VIN = 6 to 30 V
0 < VCS5 - VFB5 < 90 mV
VCS5 - VFB5
L = 10 µH, C = 330 µF
RSENSE = 20 m
4.88
5.03
90
125
50
65
VIN = 6 to 30 V, 0 < VCSP - VCSN < 300 mV
VIN = 6 to 30 V
0 < VCSP - VFBN < 300 mV
VCSP - VCSN
L = 10 µH, C = 100 µF
RSENSE = 100 m, Ccomp = 120 pF
11.4
12.0
All Converters OFF, VIN > 5.5, 0 < IL < 30 mA
4.7
3.6
330
410
10
65
5.18
± 0.5
± 0.5
160
12.6
± 0.5
± 0.5
500
75
V
%
mV
kHz
°
V
%
mV
kHz
°
V
%
mV
kHz
°
5.5
4.2
V
4.7
mV
V
mV
75
4.2
Unit
Document Number: 70818
S11-0975-Rev. D, 16-May-11
This document is subject to change without notice.
THE PRODUCTS DESCRIBED HEREIN AND THIS DOCUMENT ARE SUBJECT TO SPECIFIC DISCLAIMERS, SET FORTH AT www.vishay.com/doc?91000
End of Life. Last Available Purchase Date is 31-Dec-2014
Si9136
Vishay Siliconix
SPECIFICATIONS
Parameter
Specific Test Conditions
VIN = 15 V , IVL = IREF = 0 mA
TA = 0 °C to 90 °C, All Converters ON
Limits
Min.
Typ.b
Max.a
No External Load
3.24
3.30
3.36
V
30
75
mV
a
Unit
Reference
REF Output
REF Load Regulation
0 to 1 mA
Supply Current
Supply Current-Shutdown
All Converters OFF, No Load
35
60
Supply Current-Operation
All Converters ON, No Load, FOCS = 200 kHz
1100
1800
220
µA
Oscillator
Oscillator Frequency
180
200
Maximum Duty Cycle
92
95
kHz
%
Outputs
Gate Driver Sink/Source Current (Buck)
Gate Driver On-Resistance (Buck)
Gate Driver Sink/Source Current (Flyback)
Gate Driver On-Resistance (Flyback)
DL3, DH3, DL5, DH5 Forced to 2 V
1
High or Low
2
DHFY, DLFY Forced to 2 V
0.2
High or Low
A
7
15
A
5 ON/OFF, 3 ON/OFF, and 12 ON/OFF
VIL
0.8
VIH
V
2.4
Notes:
a. The algebraic convention whereby the most negative value is a minimum and the most positive a maximum.
b. Typical values are for DESIGN AID ONLY, not guaranteed nor subject to production testing.
PIN CONFIGURATION
SSOP-28
ORDERING DESCRIPTION
28
Part Number
2
27
Si9136LG
3
26
4
25
5
24
6
23
7
22
8
21
9
20
10
19
1
Evaluation Board
11
18
12
17
12
16
14
15
Si9136DB
Temperature Range
VOUT
0 °C to 90 °C
3.3 V, 5 V, 12 V
Temperature Range
Board Type
0 °C to 90 °C
Surface Mount
Top View
Document Number: 70818
S11-0975-Rev. D, 16-May-11
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End of Life. Last Available Purchase Date is 31-Dec-2014
Si9136
Vishay Siliconix
PIN DESCRIPTION
Pin Number
Symbol
Description
1
CS3
2
FBFY
3
BSTFY
Boost capacitor connection for flyback converter.
4
DHFY
Gate-drive output for flyback high-side MOSFET.
5
LXFY
Inductor connection for flyback converter.
6
DLFY
Gate-drive output for flyback low-side MOSFET.
7
CSP
Current sense positive input for flyback converter.
8
CSN
Current sense negative input for flyback converter.
9
GND
10
COMP
Current sense input for 3.3 V buck.
Feedback for flyback.
Analog ground.
Flyback compensation connection, if required.
11
REF
12
12 ON/OFF
3.3 V internal reference.
ON and OFF control input for 12 V flyback controller.
13
3.3 ON/OFF
ON and OFF control input for 3.3 V buck controller.
14
5 ON/OFF
15
CS5
16
DH5
Inductor connection for buck 5 V.
17
LX5
Gate-drive output for 5 V buck high-side MOSFET.
18
BST5
Boost capacitor connection for 5 V buck converter.
19
DL5
Gate-drive output for 5 V buck low-side MOSFET.
20
PGND
21
FB5
22
VL
ON and OFF control input for 5 V buck controller.
Current sense input for 5 V buck controller.
Power ground.
Feedback for 5 V buck.
5 V logic supply voltage for internal circuitry.
23
VIN
Input voltage
24
DL3
Gate-drive output for 3.3 V buck low-side MOSFET.
25
BST3
Boost capacitor connection for 3.3 V buck converter.
Inductor connection for 3.3 V buck low-side MOSFET.
26
LX3
27
DH3
Gate-drive output for 3.3 V buck high-side MOSFET.
28
FB3
Feedback for 3.3 V buck.
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Document Number: 70818
S11-0975-Rev. D, 16-May-11
This document is subject to change without notice.
THE PRODUCTS DESCRIBED HEREIN AND THIS DOCUMENT ARE SUBJECT TO SPECIFIC DISCLAIMERS, SET FORTH AT www.vishay.com/doc?91000
End of Life. Last Available Purchase Date is 31-Dec-2014
Si9136
Vishay Siliconix
TYPICAL CHARACTERISTICS (25 °C, unless otherwise noted)
100
100
Frequency = 200 kHz
Frequency = 200 kHz
90
90
VIN = 6 V
15 V
15 V
80
Efficiency (%)
Efficiency (%)
VIN = 6 V
30 V
70
80
30 V
70
5 V On, 12 V Off
3.3 V Off, 12 V Off
60
60
50
0.001
50
0.01
0.1
1
10
0.001
0.01
Current (A)
0.1
1
10
Current (A)
Efficiency vs. 3.3 V Output Current
Efficiency vs. 5.0 V Output Current
85
VIN = 15 V
Frequency = 200 kHz
80
6V
Efficiency (%)
75
30 V
70
65
5 V On, 3.3 V Off
60
55
0.001
0.01
0.1
1
Current (A)
Efficiency vs. 12 V Output Current
Document Number: 70818
S11-0975-Rev. D, 16-May-11
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THE PRODUCTS DESCRIBED HEREIN AND THIS DOCUMENT ARE SUBJECT TO SPECIFIC DISCLAIMERS, SET FORTH AT www.vishay.com/doc?91000
End of Life. Last Available Purchase Date is 31-Dec-2014
Si9136
Vishay Siliconix
TYPICAL WAVEFORMS
Ch1: VOUT
Ch1: VOUT
Ch2: Load
Current (1 A/div)
Ch2: Load
Current (1 A/div)
PWM Loading
PWM Unloading
5 V Converter (VIN = 10 V)
5 V Converter (VIN = 10 V)
Ch1: VOUT
Ch1: VOUT
Ch2: Load
Current (1 A/div)
Ch2: Load
Current (1 A/div)
PSM Õ PWM
PWM Õ PSM
5 V Converter (VIN = 10 V)
5 V Converter (VIN = 10 V)
PSM Operation
5 V Converter (VIN = 10 V)
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Ch2: VOUT
Ch2: VOUT
Ch3: Inductor
Node
(L X5)
Ch3: Inductor
Node
(L X5)
Ch4: Inductor
Current (1A/div)
Ch4: Inductor
Current (1A/div)
PWM Operation
5 V Converter (VIN = 10 V)
Document Number: 70818
S11-0975-Rev. D, 16-May-11
This document is subject to change without notice.
THE PRODUCTS DESCRIBED HEREIN AND THIS DOCUMENT ARE SUBJECT TO SPECIFIC DISCLAIMERS, SET FORTH AT www.vishay.com/doc?91000
End of Life. Last Available Purchase Date is 31-Dec-2014
Si9136
Vishay Siliconix
TYPICAL WAVEFORMS
Ch1: VOUT
Ch1: VOUT
Ch2: Load
Current (1 A/div)
Ch2: Load
Current (1 A/div)
PWM, Loading
PWM, Unloading
3 V Converter (VIN = 10 V)
3 V Converter (VIN = 10 V)
Ch1:
VOUT
Ch1:
VOUT
Ch2: Load
Current (1 A/div)
Ch2: Load
Current (1 A/div)
PSM Õ PWM
PWM Õ PSM
3 V Converter (VIN = 10 V)
3 V Converter (VIN = 10 V)
3.3 V Output
5 V Output
Ch1: VOUT
12 V Output
Inductor Current,
5 V Converter
(2 A/div)
Ch4: Load
Current
(100 mA/div)
250 mA Transient
12 V Converter (VIN = 10 V)
Document Number: 70818
S11-0975-Rev. D, 16-May-11
Start-Up
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End of Life. Last Available Purchase Date is 31-Dec-2014
Si9136
Vishay Siliconix
STANDARD APPLICATION CIRCUIT
V IN
+ 5 V up to 30 mA
C7
33 µF
D1
CMPD2836
CMPD2836
VIN
D2
VL
C1
0.1 µF
BST3
C2
0.1 µF
BST5
Q2
Si4416DY
L1, 10 µH
DH5
Q1
Si4416DY
DH3
C5
4.7 µF
C4
33 µF
R7
Rcs1
0.02 Ω
C3
330 µF
LX3
+ 3.3 V
R1
Rcs2
0.02 Ω
L2
10 µH
Q4
Si4812DY
DL5
Q3
Si4812DY
+5V
LX5
DL3
CS5
C6
330 µF
FB5
D3 CMPD2836
CS3
C9
4.7 µF
C8
BSTFY
0.1 µF
DHFY
Q5
Si2304DS
L3, 10 µH
D4, D1FS4
+ 12 V 0 to
250 mA
LXFY
C10
100 µF
D5, D1FS4
FB3
Q6
Si2304DS
DLFY
CSP
5 ON/OFF
R6
Rcs3
3.3 ON/OFF
12 ON/OFF CSN
FBFY
+ 3.3 V up
to 1 mA
C11
1 µF
REF
COMP
GND
PGND
C12
120 pF
Figure 1.
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Document Number: 70818
S11-0975-Rev. D, 16-May-11
This document is subject to change without notice.
THE PRODUCTS DESCRIBED HEREIN AND THIS DOCUMENT ARE SUBJECT TO SPECIFIC DISCLAIMERS, SET FORTH AT www.vishay.com/doc?91000
End of Life. Last Available Purchase Date is 31-Dec-2014
Si9136
Vishay Siliconix
TIMING DIAGRAMS
The converter is enabled
ON/OFF
VIN is applied
VIN
LDO is activated
after VIN is applied
VL
REF circuit is activated
after VL becomes
available
After VREF goes above
2.4 V, the converter is
turned on
2.4 V
VREF
OSC EN
(Sysmon EN)
Oscillator is activated
OSC
Slow soft-start gradually
increases the maximum
inductor current
4 ms
fmax (SS)
High-side gate drive duty
ratio gradually increases
to maximum
DH
tBBM
Low-side gate drive
DL
Figure 2. Converter is Enabled Before VIN is Applied
The converter is
enabled
ON/OFF
VIN is applied
VIN
LDO is activated
after VIN is applied
VL
REF circuit is activated
after VL becomes
available
After VREF goes above
2.4 V, the converter is
turned on
2.4 V
VREF
OSC EN
(Sysmon EN)
Oscillator is activated
OSC
4 ms
fmax (SS)
Slow soft-start gradually
increases the maximum
inductor current
DH
DL
Figure 3. Converter is Enabled After VIN is Applied
Document Number: 70818
S11-0975-Rev. D, 16-May-11
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End of Life. Last Available Purchase Date is 31-Dec-2014
Si9136
Vishay Siliconix
TIMING DIAGRAMS
VIN
≈ V (VL)
VL
4V
3.4 V
RESET
VREF
OSC EN
(Sysmon EN)
OSC
DH
DL
fmax (SS)
Figure 4. Power Off Sequence
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Document Number: 70818
S11-0975-Rev. D, 16-May-11
This document is subject to change without notice.
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End of Life. Last Available Purchase Date is 31-Dec-2014
Si9136
Vishay Siliconix
DETAIL FUNCTIONAL BLOCK DIAGRAM
FB5
+
CS_
-
FB_
1X
Error
Amplifier
REF
RX
RY
5/3 ON/OFF_
PWMCMP
+
BST_
-
DH
+
DH
Logic
Control
Pulse
Skipping
Control
SLC
Internal voltage
divider is only
used on 5 V
output.
LX_
BBM
20 mV
VL
Current
Limit
DL
DL
V
Soft-Start
SYNC
Rectifier Control
t
Figure 5. Buck Block Diagram
FBFY
R1
ON/OFF
Error
Amplifier
PWM
Comparator
REF
-
+
Logic
Control
+
R2
BSTY
DH
LXFY
COMP
DHFY
C/S
Amplifier
ICSP
-
ICSN
+
Pulse
Skipping
Control
DL
DLFY
100 mV
+
Current Limit
V
Soft-Start
t
Figure 6. PWM Flyback Block Diagram
Document Number: 70818
S11-0975-Rev. D, 16-May-11
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Si9136
Vishay Siliconix
DETAIL FUNCTIONAL BLOCK DIAGRAM
VIN
5V
Linear
Regulator
FB5
5 ON/OFF
VL
5V
Buck
Controller
CS5
BST5
DH5
LX5
4.5 V
DL5
4V
FB3
Logic
Control
3.3 V
Reference
3 ON/OFF
3.3 V
Buck
Controller
2.4 V
CS3
BST3
DH3
LX3
DL3
FYBFY
ICSP
12 ON/OFF
12 V
Flyback
Controller
ICSN
BSTFY
DHFY
LXFY
DLFY
Figure 7. Complete Si9136 Block Diagram
DESCRIPTION OF OPERATION
Start-up Sequence
Si9136’s outputs are controlled by three specific input control
lines; 3.3 ON/OFF, 5 ON/OFF, and 12 ON/OFF. Once VIN is
applied, the VL, the 5 V LDO will come up within its tolerance.
When any one of these control lines becomes logic high, the
precision 3.3 V reference will also come up. Immediately
afterwards, the oscillator will begin and the corresponding
converter will come up with its own tolerance. In the event of
all three converters are turned off, the oscillator and the
reference output will be turned off, and the total system will
only draw 35 µA of supply current.
Switch-mode supply output current capabilities depend on
external components (can be selected to exceed 10 A). In
the standard application circuit illustrated in Figure 1, each
buck converter is capable of delivering 5 A, with the flyback
converter delivering 250 mA. The recommended load
currents for the precision 3.3 V reference output is less than
1 mA, and the 5 V LDO output is less than 30 mA. In order to
maximize power efficiency of the converter, when the 5 V
buck converter output (FB5) voltage is above 4.5 V, the
internal 5 V LDO is turned off and VL is supplied by the 5 V
converter output.
Buck Converter Operation:
Each converter can soft-start independently. This internal
soft-start circuitry for each converter will gradually increases
the inductor maximum peak current during the soft-start
period (approximately 4 ms), preventing excessive currents
from being drawn from the input.
Si9136 converts a 5.5 V to 30 V input voltage to five different
output voltages; two buck (step-down) high current, PWM,
switch-mode supplies of 3.3 V and 5 V, one "flyback" PWM
switch-mode supply of 12 V, one precision 3.3 V reference
and one 5 V low drop out (LDO) linear regulator output.
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The 3.3 V and 5 V buck converters are both current-mode
PWM and PSM (during light load operation) regulators using
high-side bootstrap N-Channel and low-side N-Channel
MOSFETs. At light load conditions, the converters switch at
a lower frequency than the clock frequency, seen like some
clock pulses between the actual switching are skipped, this
operating condition is defined as pulse-skipping. The
operation of the converter(s) switching at clock frequency is
defined as normal operation.
Document Number: 70818
S11-0975-Rev. D, 16-May-11
This document is subject to change without notice.
THE PRODUCTS DESCRIBED HEREIN AND THIS DOCUMENT ARE SUBJECT TO SPECIFIC DISCLAIMERS, SET FORTH AT www.vishay.com/doc?91000
End of Life. Last Available Purchase Date is 31-Dec-2014
Si9136
Vishay Siliconix
DESCRIPTION OF OPERATION (CONT’D)
Normal Operation: Buck Converters
In normal operation, the buck converter high-side MOSFET
is turned on with a delay (known as break-before-make time
- tBBM), after the rising edge of the clock. After a certain on
time, the high-side MOSFET is turned off and then after a
delay (tBBM), the low-side MOSFET is turned on until the next
rising edge of the clock, or the inductor current reaches zero.
The tBBM (approximately 25 ns to 60 ns), has been optimized
to guarantee the efficiency is not adversely affected at the
high switching frequency and a specified minimum to
account for variations of possible MOSFET gate
capacitances.
During the normal operation, the high-side MOSFET switch
on-time is controlled internally to provide excellent line and
load regulation over temperature. Both buck converters
should have load, line, regulation to within 0.5 % tolerance.
Pulse Skipping: Buck Converters
When the buck converter switching frequency is less than
the internal clock frequency, its operation mode is defined as
pulse skipping mode. During this mode, the high-side
MOSFET is turned on until VCS-VFB reaches 20 mV, or the
on time reaches its maximum duty ratio. After the high-side
MOSFET is turned off, the low-side MOSFET is turned on
after the tBBM delay, which will remain on until the inductor
current reaches zero. The output voltage will rise slightly
above the regulation voltage after this sequence, causing the
controller to stay idle for the next one, or several clock cycles.
When the output voltage falls slightly below the regulation
level, the high-side MOSFET will be turned on again at the
next clock cycle. With the converter remaining idle during
some clock cycles, the switching losses are reduced in order
to preserve conversion efficiency during the light output
current condition.
It consists of two N-Channel MOSFET switches that are
turned on and off in phase, and two diodes. Similar to the
buck converter, during the light load conditions, the flyback
converter will switch at a frequency lower than the internal
clock frequency, which can be defined as pulse skipping
mode (PSM); otherwise, it is operating in normal PWM mode.
Normal Operation: Flyback Converter
In normal operation mode, the two MOSFETs are turned on
at the rising edge of the clock, and then turned off. The on
time is controlled internally to provide excellent load, line,
and temperature regulation. The flyback converter has load,
line and temperature regulation well within 0.5 %.
Pulse Skipping: Flyback Converter
Under the light load conditions, similar to the buck converter,
the flyback converter will enter pulse skipping mode. The
MOSFETs will be turned on until the inductor current
increases to such a level that the voltage across the pin CSP
and pin CSN reaches 100 mV, or the on time reaches the
maximum duty cycle. After the MOSFETs are turned off, the
inductor current will conduct through two diodes until it
reaches zero. At this point, the flyback converter output will
rise slightly above the regulation level, and the converter will
stay idle for one or several clock cycle(s) until the output falls
back slightly below the regulation level. The switching losses
are reduced by skipping pulses and so the efficiency during
light load is preserved.
Current Limit: Flyback Converter
Similar to the buck converter; when the voltage across pin
CSP and pin CSN exceeds 410 mV typical, the two
MOSFETs will be turned off regardless of the input and
output conditions.
Current Limit: Buck Converters
Flyback Lowside Drive
When the buck converter inductor current is too high, the
voltage across pin CS3(5) and pin FB3(5) exceeds
approximately 120 mV, the high-side MOSFET would be
turned off instantaneously regardless of the input, or output
condition. The Si9136 features clock cycle by clock cycle
current limiting capability.
Flyback Converter Operation:
Unlike the gate drive for the two buck converters, the flyback
lowside gate drive DLFY is powered by a voltage that can be
as high as 15 V with 20 V input for the flyback converter. If
this poses concerns on the MOSFET VGS rating, a simple
resistor-zener circuit can be used: a resistor series with gate
and zener diode across the gate and source to clamp its
voltage. A 100 , 10 V combination works well.
Designed mainly for PCMCIA or EEPROM programming, the
Si9136 has a 12 V output non-isolated buck boost converter,
called for brevity a flyback.
Document Number: 70818
S11-0975-Rev. D, 16-May-11
www.vishay.com
13
This document is subject to change without notice.
THE PRODUCTS DESCRIBED HEREIN AND THIS DOCUMENT ARE SUBJECT TO SPECIFIC DISCLAIMERS, SET FORTH AT www.vishay.com/doc?91000
End of Life. Last Available Purchase Date is 31-Dec-2014
Si9136
Vishay Siliconix
DESCRIPTION OF OPERATION (CONT’D)
Grounding:
There are two separate grounds on the Si9136, analog
signal ground (GND) and power ground (PGND). The
purpose of two separate grounds is to prevent the high
currents on the power devices (both external and internal)
from interfering with the analog signals. The internal
components of Si9136 have their grounds tied (internally)
together. These two grounds are then tied together
(externally) at a single point, to ensure Si9136 noise
immunity.
This separation of grounds should be maintained in the
external circuitry, with the power ground of all power devices
being returned directly to the input capacitors, and the small
signal ground being returned to the GND pin of Si9136.
ON/OFF Function
Logic-low shuts off the appropriate section by disabling the
gate drive stage. High-side and low-side gate drivers are
turned off when ON/OFF pins are logic-low. Logic-high
enables the DH and DL pins.
Stability:
Buck Converters:
In order to simplify designs, the Si9136 requires no specified
external components except load capacitors for stability
control. Meanwhile, it achieves excellent regulation and
efficiency. The converters are current mode control, with a
bandwidth substantially higher than the LC tank dominant
pole frequency of the output filter. To ensure stability, the
minimum capacitance and maximum ESR values are:
VREF
CLOAD ≥ 2π x
VOUT x RCS x BW
ESR ≤
VOUT x Rcs
VREF
Where VREF = 3.3 V, VOUT is the output voltage
(5 V or 3.3 V), Rcs is the current sensing resistor in ohms
and BW = 50 khz
With the components specified in the application circuit
(L = 10 µH, RCS = 0.02 , COUT = 330 µF, ESR
approximately 0.1 , the converter should have a bandwidth
at approximately 50 kHz, with minimum phase margin of 65°,
and dc gain above 50 dB.
Other Outputs
The Si9136 also provides a 3.3 V reference which can be
external loaded up to 1 mA, as well as, a 5 V LDO output
which can be loaded 30 mA, or even more depending on the
system application. When the 5 V buck converter is turned
on, the 5 V LDO output is shorted with the 5 V buck converter
output, so its loading capability is substantially increased.
For stability, the 3.3 V reference output requires a 1 µF
capacitor, and 5 V LDO output requires a 4.7 µF capacitor.
Vishay Siliconix maintains worldwide manufacturing capability. Products may be manufactured at one of several qualified locations. Reliability data for Silicon
Technology and Package Reliability represent a composite of all qualified locations. For related documents such as package/tape drawings, part marking, and
reliability data, see www.vishay.com/ppg?70818.
www.vishay.com
14
Document Number: 70818
S11-0975-Rev. D, 16-May-11
This document is subject to change without notice.
THE PRODUCTS DESCRIBED HEREIN AND THIS DOCUMENT ARE SUBJECT TO SPECIFIC DISCLAIMERS, SET FORTH AT www.vishay.com/doc?91000
Package Information
Vishay Siliconix
SSOP: 28-LEAD (5.3 MM) (POWER IC ONLY)
28
15
−B−
E1
1
E
14
−A−
D
e
0.25
GAUGE PLANE
R
c
A2 A
A1
−C−
0.076
L
SEATING PLANE
C
b
0.12 M
A
B
C
SEATING PLANE
L1
S
MILLIMETERS
Dim
A
A1
A2
b
c
D
E
E1
e
L
L1
R
Min
Nom
Max
1.73
1.88
1.99
0.05
0.13
0.21
1.68
1.75
1.78
0.25
0.30
0.38
0.09
0.15
0.20
10.07
10.20
10.33
7.60
7.80
8.00
5.20
5.30
5.40
0.65 BSC
0.63
0.75
0.95
1.25 BSC
0.09
0.15
−−−
0_
4_
8_
ECN: S-40080—Rev. A, 02-Feb-04
DWG: 5915
Document Number: 72810
28-Jan-04
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1
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Disclaimer
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