TSS721A
www.ti.com
SLAS222B – APRIL 1999 – REVISED NOVEMBER 2010
METER-BUS TRANSCEIVER
Check for Samples: TSS721A
FEATURES
1
•
•
•
•
•
•
•
•
•
•
Meter-Bus Transceiver (for Slave) Meets
Standard EN1434-3
Receiver Logic With Dynamic Level
Recognition
Adjustable Constant-Current Sink via Resistor
Polarity Independent
Power-Fail Function
Module Supply Voltage Switch
3.3-V Constant Voltage Source
Remote Powering
Up to 9600 Baud in Half Duplex for UART
Protocol
Slave Power Support
– Supply From Meter-Bus via Output VDD
– Supply From Meter-Bus via Output VDD or
From Backup Battery
– Supply From Battery – Meter-Bus Active for
Data Transmission Only
D PACKAGE
(TOP VIEW)
BUSL2
1
16
BUSL1
VB
2
15
GND
STC
3
14
RIS
RIDD
4
13
RXI
PF
5
12
RX
SC
6
11
VDD
TXI
7
10
VS
TX
8
9
BAT
DESCRIPTION
TSS721A is a single chip transceiver developed for Meter-Bus standard (EN1434-3) applications.
The TSS721A interface circuit adjusts the different potentials between a slave system and the Meter- Bus
master. The connection to the bus is polarity independent and supports full galvanic slave isolation with
optocouplers.
The circuit is supplied by the master via the bus. Therefore, this circuit offers no additional load for the slave
battery. A power-fail function is integrated.
The receiver has dynamic level recognition, and the transmitter has a programmable current sink.
A 3.3-V voltage regulator, with power reserve for a delayed switch off at bus fault, is integrated.
Table 1. ORDERING INFORMATION (1) (2)
TA
0°C to 70°C
(1)
(2)
PACKAGE
SOIC – D
ORDERABLE PART NUMBER
Reel of 2500
TSS721ADR
For the most current package and ordering information, see the Package Option Addendum at the end of this document, or see the TI
web site at www.ti.com.
Package drawings, thermal data, and symbolization are available at www.ti.com/packaging.
1
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas
Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.
Copyright © 1999–2010, Texas Instruments Incorporated
TSS721A
SLAS222B – APRIL 1999 – REVISED NOVEMBER 2010
www.ti.com
FUNCTIONAL DESCRIPTION
CS1
VB
IBUS
ICI2
PF
TC2
RIDD
ICS3
BAT
VF
ISTC
STC
ISTC_use
BUSL1
BR
ICI1
BUSL2
CS2
TX
TC3
TXI
SC
VS
TC1
IMS
VDD
IVDD
VVDD
3.3 V
REF2
1.3 V
REF1
7V
CS3
ECHO
RX
TC4
RVS
RXI
RIS
GND
Figure 1. Functional Schematic
Table 2. Terminal Functions
TERMINAL
DESCRIPTION
NAME
NO.
BUSL2
1
Meter-Bus
VB
2
Differential bus voltage after rectifier
STC
3
Support capacitor
RIDD
4
Current adjustment input
PF
5
Power fail output
SC
6
Sampling capacitor
TXI
7
Data output inverted
TX
8
Data output
BAT
9
Logic level adjust
VS
10
Switch for bus or battery supply output
VDD
11
Voltage regulator output
RX
12
Data input
RXI
13
Data input inverted
RIS
14
Adjust input for modulation current
GND
15
Ground
BUSL1
16
Meter-Bus
2
Submit Documentation Feedback
Copyright © 1999–2010, Texas Instruments Incorporated
Product Folder Link(s): TSS721A
TSS721A
www.ti.com
SLAS222B – APRIL 1999 – REVISED NOVEMBER 2010
Data Transmission, Master to Slave
The mark level on the bus lines VBUS = MARK is defined by the difference of BUSL1 and BUSL2 at the slave. It
is dependent on the distance of Master to Slave, which affects the voltage drop on the wire. To make the
receiver independent, a dynamic reference level on the SC pin is used for the voltage comparator TC3 (see
Figure 2).
IBUS
VB
to IC
VBUS
IBUS
VMARK = 20.8 V to 42 V
VT
BUSL1
BUSL2
TC3
BR
ISCcharge
VSPACE = VMARK – 10 V
TX
IBUS = Constant
TXI
SC
VTX
ISCdischarge
CSC
GND
VTXI
CBUSL1-BUSL2 = 30 pF typ
VB = 25 V, fmeas = 1 MHz
Figure 2. Data Transmission, Master to Slave
A capacitor CSC at pin SC is charged by a current ISCcharge and is discharged with a current ISCdischarge where:
ISCcharge
ISCdisharge =
40 (typ)
(1)
This ratio is necessary to run any kind of UART protocol independent of the data contents. (for example, if an
11-bit UART protocol is transmitted with all data bits at 0 and only the stop bit at 1). There must be sufficient time
to recharge the capacitor CSC. The input level detector TC3 detects voltage modulations from the master,
VBUS = SPACE/MARK conditions, and switches the inverted output TXI and the non-inverted output TX.
Submit Documentation Feedback
Copyright © 1999–2010, Texas Instruments Incorporated
Product Folder Link(s): TSS721A
3
TSS721A
SLAS222B – APRIL 1999 – REVISED NOVEMBER 2010
www.ti.com
Data Transmission, Slave to Master
The device uses current modulation to transmit information from the slave to the master while the bus voltage
remains constant. The current source CS3 modulates the bus current and the master detects the modulation.
The constant current source CS3 is controlled by the inverted input RXI or the non-inverted input RX. The current
source CS3 can be programmed by an external resistor RRIS. The modulation supply current IMS flows in addition
to the current source CS3 during the modulation time.
VRX
IBUS
VB
to IC
ICS3
IMS
VRXI
CS3
BUSL1
BUSL2
BR
TC4
RX
RXI
RIS
VBUS
IBUS
VBUS = Constant
RRIS
GND
IMC
ISPACE
IMARK
IMC = IMS + ICS3
Figure 3. Data Transmission, Slave to Master
Because the TSS721A is configured for half-duplex only, the current modulation from RX or RXI is repeated
concurrently as ECHO on the outputs TX and TXI. If the slave, as well as the master, is trying to send
information via the lines, the added signals appear on the outputs TX and TXI, which indicates the data collision
to the slave (see Figure 1).
The bus topology requires a constant current consumption by each connected slave.
To calculate the value of the programming resistor RRIS, use the formula shown in Figure 4.
IMC
(mA)
RRIS =
20
VRIS
VRIS
=
ICS3 IMC – IMS
VRIS = Voltage on pin RIS
RRIS = Programming resistor
ICS3 = Programmable current
IMC = Modulation current
IMS = Modulation supply current (220 µA typ)
15
10
Typical
5
0
0.1
0.2
0.5
1
RRIS (kW)
Figure 4. Calculate Programming Resistor RRIS
4
Submit Documentation Feedback
Copyright © 1999–2010, Texas Instruments Incorporated
Product Folder Link(s): TSS721A
TSS721A
www.ti.com
SLAS222B – APRIL 1999 – REVISED NOVEMBER 2010
Slave Supply, 3.3 V
The TSS721A has an internal 3.3-V voltage regulator. The output power of this voltage regulator is supplied by
the storage capacitor CSTC at pin STC. The storage capacitor CSTC at pin STC is charged with constant current
ISTC_use from the current source CS1. The maximum capacitor voltage is limited to REF1. The charge current ISTC
has to be defined by an external resistor at pin RIDD.
The adjustment resistor RRIDD can be calculated using Equation 2.
V
VRIDD
RRID = 25 RIDD = 25
ISTC
ISTC_use + IIC1
(2)
Where,
ISTC = current from current source CS1
ISTC_use = charge current for support capacitor
ICI = internal current
VRIDD = voltage on pin RIDD
RRIDD = value of adjustment resistor
The voltage level of the storage capacitor CSTC is monitored with comparator TC1. Once the voltage VSTC
reaches VVDD_on, the switch SVDD connects the stabilized voltage VVDD to pin VDD. VDD is turned off if the
voltage VSTC drops below the VVDD_off level.
Voltage variations on the capacitor CSTC create bus current changes (see Figure 5).
IBUS
(mA)
916
914
912
910
1
2
3
4
5
6
7
8
VSTC (V)
Figure 5. Single Mode Bus Load
At a bus fault the shut down time of VDD (toff) in which data storage can be performed depends on the system
current IVDD and the value of capacitor CSTC. See Figure 6, which shows a correlation between the shutdown of
the bus voltage VBUS and VDD_off and toff for dimensioning the capacitor.
The output VS is meant for slave systems that are driven by the bus energy, as well as from a battery should the
bus line voltage fail. The switching of VS is synchronized with VDD and is controlled by the comparator TC1. An
external transistor at the output VS allows switching from the Meter-Bus remote supply to battery.
Submit Documentation Feedback
Copyright © 1999–2010, Texas Instruments Incorporated
Product Folder Link(s): TSS721A
5
TSS721A
SLAS222B – APRIL 1999 – REVISED NOVEMBER 2010
www.ti.com
Power On/Off
VBUS
VVB =VSTC + 0.6 V
typical threshold voltage
for power fail PF
ton
VSTC
VDDon
VDDoff
VVS
VVDD
toff
VPF
V
– VVDDoff
toff = CSTC STC
IVDD + ICI1
Figure 6. Power On/Off Timing
Power Fail Function
Because of the rectifier bridge BR at the input, BUSL1, and BUSL2, the TSS721A is polarity independent. The
pin VB to ground (GND) delivers the bus voltage VVB less the voltage drop over the rectifier BR. The voltage
comparator TC2 monitors the bus voltage. If the voltage VVB > VSTC + 0.6 V, then the output PF = 1. The output
level PF = 0 (power fail) provides a warning of a critical voltage drop to the microcontroller to save the data
immediately.
6
Submit Documentation Feedback
Copyright © 1999–2010, Texas Instruments Incorporated
Product Folder Link(s): TSS721A
TSS721A
www.ti.com
SLAS222B – APRIL 1999 – REVISED NOVEMBER 2010
ABSOLUTE MAXIMUM RATINGS
over operating free-air temperature range (unless otherwise noted)
VMB
Voltage, BUSL1 to BUSL2
±50 V
RX and RXI
–0.3 V to 5.5 V
VI
Input voltage range
TJ
Operating junction temperature range
TA
Operating free-air temperature range
–25°C to 85°C
TSTG
Storage temperature range
–65°C to 150°C
BAT
–0.3 V to 5.5 V
–25°C to 150°C
Power derating factor, junction to ambient
8 mW/°C
RECOMMENDED OPERATING CONDITIONS (1)
MIN
MAX
10.8
42
Transmitter
12
42
VB (receive mode)
9.3
BAT (2)
2.5
3.8
13
80
Receiver
VMB
Bus voltage, |BUSL2 – BUSL1|
VI
Input voltage
RRIDD
RIDD resistor
RRIS
RIS resistor
100
TA
Operating free-air temperature
–25
85
TYP
MAX
(1)
(2)
UNIT
V
V
kΩ
Ω
°C
All voltage values are measured with respect to the GND terminal unless otherwise noted.
VBAT(max) ≤ VSTC – 1 V
ELECTRICAL CHARACTERISTICS (1)
over operating free-air temperature range (unless otherwise noted)
PARAMETER
TEST CONDITIONS
MIN
UNIT
ΔVBR
Voltage drop at rectifier BR
IBUS = 3 mA
1.5
V
ΔVCS1
Voltage drop at current
source CS1
RRIDD = 13 kΩ
1.8
V
IBUS
BUS current
VSTC = 6.5 V,
IMC = 0 mA
ΔIBUS
BUS current accuracy
ΔVBUS = 10 V, IMC = 0 mA, RRIDD = 13 kΩ to 30 kΩ
ICC
RRIDD = 13 kΩ
3
RRIDD = 30 kΩ
1.5
VSTC = 6.5 V, IMC = 0 mA, VBAT = 3.8 V, RRIDD = 13 kΩ
ICI1
CI1 current
VSTC = 6.5 V, IMC = 0 mA, VBAT = 3.8 V, RRIDD = 13 kΩ,
VBUS = 6.5 V, RX/RXI = off (2)
IBAT
BAT current
IBAT + IVDD BAT plus VDD current
VBUS = 0 V, VSTC = 0 V
VVDD
VDD voltage
–IVDD = 1 mA, VSTC = 6.5 V
RVDD
VDD resistance
–IVDD = 2 to 8 mA, VSTC = 4.5 V
VSTC
STC voltage
µA
350
µA
–0.5
0.5
µA
–0.5
0.5
µA
3.1
3.4
V
5
Ω
5.6
6.4
3.8
4.3
IVDD < ISTC_use
6.5
7.5
RRIDD = 30 kΩ
0.65
1.1
RRIDD = 13 kΩ
1.85
2.4
VSTC = 5 V
VRIDD
RIDD voltage
RRIDD = 30 kΩ
VVS
VS voltage
VDD = on, IVS = –5 µA
RVS
VS resistance
VDD = off
VSTC = 6.5 V
V
mA
1.23
1.33
V
VSTC – 0.4
VSTC
V
0.3
1
VBAT – 0.6
VBAT
VVB = VSTC + 0.3 V, IPF = 1 µA
0
0.6
VVB = VSTC + 0.3 V, IPF = 5 µA
0
0.9
VVB = VSTC + 0.8 V, IPF = –100 µA
(1)
(2)
650
VDD = off, VS = off
STC current
PF voltage
%
VDD = on, VS = on
ISTC_use
VPF
2
(2)
Supply current
mA
MΩ
V
All voltage values are measured with respect to the GND terminal, unless otherwise noted.
Inputs RX/RXI and outputs TX/TXI are open, ICC = ICI1 + ICI2
Submit Documentation Feedback
Copyright © 1999–2010, Texas Instruments Incorporated
Product Folder Link(s): TSS721A
7
TSS721A
SLAS222B – APRIL 1999 – REVISED NOVEMBER 2010
www.ti.com
ELECTRICAL CHARACTERISTICS(1) (continued)
over operating free-air temperature range (unless otherwise noted)
PARAMETER
ton
Turn-on time
TEST CONDITIONS
MIN
TYP
CSTC = 50 µF, Bus voltage slew rate: 1 V/µs
MAX
3
UNIT
s
RECEIVER SECTION ELECTRICAL CHARACTERISTICS (1)
over operating free-air temperature range (unless otherwise noted)
PARAMETER
VT
TEST CONDITIONS
MIN
See Figure 2
VSC
SC voltage
ISCcharge
SC charge current
TYP
MAX
MARK
– 8.2
VSC = 24 V, VVB = 36 V
V
VVB
V
–15
–40
µA
0.3
–0.033 ×
ISCcharge
µA
VBAT –
0.6
VBAT
V
ISCdischarge
SC discharge current
VSC = VVB = 24 V
VOH
High-level output voltage
(TX, TXI)
ITX/ITXI = –100 µA (see Figure 2)
VOL
Low-level output voltage
(TX, TXI)
ITX/ITXI = 100 µA
0
0.5
ITX = 1.1 mA
0
1.5
ITX
ITXI
TX, TXI current
VTX = 7.5, VVB = 12 V, VSTC = 6 V, VBAT = 3.8 V
(1)
UNIT
MARK –
5.7
10
V
µA
All voltage values are measured with respect to the GND terminal, unless otherwise noted.
TRANSMITTER SECTION ELECTRICAL CHARACTERISTICS (1)
over operating free-air temperature range (unless otherwise noted)
PARAMETER
IMC
MC voltage
TEST CONDITIONS
MAX
UNIT
mA
11.5
19.5
RRIS = 100 Ω
1.4
1.7
RRIS = 1000 Ω
1.5
1.8
VBAT –
0.8
5.5
V
0
0.8
V
RIS voltage
VIH
High-level input voltage (RX, RXI)
See Figure 3, see
VIL
Low-level input voltage (RX, RXI)
See Figure 3
IRX
RX current
IRXI
RXI current
8
TYP
RRIS = 100 Ω
VRIS
(1)
(2)
MIN
(2)
VRX = VBAT = 3 V, VVB = VSTC = 0 V
-0.5
0.5
VRX = 0 V, VBAT = 3 V, VSTC = 6.5 V
-10
-40
VRXI = VBAT = 3 V, VVB = VSTC = 0 V
10
40
VRXI = VBAT = 3 V, VSTC = 6.5 V
10
40
V
µA
µA
All voltage values are measured with respect to the GND terminal, unless otherwise noted.
VIH(max) = 5.5 V is valid only when VSTC > = 6.5 V.
Submit Documentation Feedback
Copyright © 1999–2010, Texas Instruments Incorporated
Product Folder Link(s): TSS721A
TSS721A
www.ti.com
SLAS222B – APRIL 1999 – REVISED NOVEMBER 2010
APPLICATION INFORMATION
Remote Supply
11
9
10
5
12
13
8
7
CST
Sensor System
(e.g., MSP430)
VDD
BAT
VS
PF
RX
RXI
TX
TXI
RIS
BUSL2
RL1
1
220
2
VB
TSS721A
BUSL1
RL2
16
220
SC GND RIDD
6
14
15
STC
4
3
T1
RRIS
RRIDD
+ CSTC
CSC
Meter-Bus
RRIDD = 30 kW
CSTC =< 220 µF
single load 1UL
RRIDD = 13 kW
CSTC =< 470 µF
double load 2UL
NOTE: Transistor T1 should be a BSS84.
Figure 7. Basic Application Circuit Using Support Capacitor CSTC > 50 µF
11
9
10
5
12
13
8
7
+ BAT
CSSC
Sensor System
(e.g., MSP430)
VDD
BAT
VS
PF
RX
RXI
TX
TXI
BUSL2
CVDD
RL1
220
VB
TSS721A
BUSL1
2
16
RL2
220
14
RRIS
Rload
1
6
15
CSC
4
RRIDD
3
+
CSTC
Meter-Bus
CSSC - system stabilising capacitor
CSTC - support capacitor
CSC - sampling capacitor
CVDD - stabilising capacitor (100 nF)
CSTC:CVDD >= 4:1
RRIDD - slave-current adjustment resistor
RRIS - modulation-current resistor
RL1,RL2 - protection resistors
Rload - discharge resistor (100 kW recommended)
Figure 8. Basic Application Circuit for Supply From Battery
Submit Documentation Feedback
Copyright © 1999–2010, Texas Instruments Incorporated
Product Folder Link(s): TSS721A
9
TSS721A
SLAS222B – APRIL 1999 – REVISED NOVEMBER 2010
www.ti.com
Remote Supply
11
9
10
5
12
13
8
7
Sensor System
(e.g., MSP430)
CSSC
RL1
BUSL2 1
VDD
BAT
VS
PF
RX
RXI
TX
TXI
RIS
220
VB 2
TSS721A
RL2
BUSL1 16
220
SC
GND RIDD STC
6
14
15
RRIS
4
3
RRIDD
CSC
+ CSTC
Remote Supply/Battery Support
11
9
10
5
12
13
8
7
T1
+ BAT
Sensor System
(e.g., MSP430)
CSSC
SC
Sensor System
(e.g., MSP430)
CSSC
15
4
3
RRIDD
+ CSTC
RL1
BUSL2 1
VDD
BAT
VS
PF
RX
RXI
TX
TXI
RIS
220
VB 2
TSS721A
RL2
BUSL1 16
220
SC
14
GND RIDD STC
6
15
RRIS
Rload
220
GND RIDD STC
6
CSC
+ BAT
RL2
BUSL1 16
RRIS
11
9
10
5
12
13
8
7
220
VB 2
TSS721A
14
Battery Supply
RL1
BUSL2 1
VDD
BAT
VS
PF
RX
RXI
TX
TXI
RIS
4
RRIDD
CSC
CVDD
3
+ CSTC
Meter-Bus
NOTE: RDSon of the transistor T1 (BSS84) at low battery voltage must be considered during application design.
Figure 9. Basic Applications for Different Supply Modes
R3
RXI
OC2
R1
+ BAT
C SSC
Sensor System
(e.g., MSP430)
TXI
R4
11
9
10
5
12
13
8
7
OC1
VDD
BAT
VS
PF
RX
RXI
TX
TXI
RIS
14
R2
Rload
BUSL2 1
220
VB 2
TSS721A
BUSL1 16
RL2
220
SC GND RIDD STC
6
R RIS
C VDD
RL1
15
4
3
RRIDD
C SC
+ C STC
Meter-Bus
Figure 10. Basic Optocoupler Application
10
Submit Documentation Feedback
Copyright © 1999–2010, Texas Instruments Incorporated
Product Folder Link(s): TSS721A
PACKAGE OPTION ADDENDUM
www.ti.com
10-Aug-2022
PACKAGING INFORMATION
Orderable Device
Status
(1)
Package Type Package Pins Package
Drawing
Qty
Eco Plan
(2)
Lead finish/
Ball material
MSL Peak Temp
Op Temp (°C)
Device Marking
(3)
Samples
(4/5)
(6)
TSS721AD
ACTIVE
SOIC
D
16
40
RoHS & Green
NIPDAU
Level-1-260C-UNLIM
-25 to 85
TSS721A
Samples
TSS721ADR
ACTIVE
SOIC
D
16
2500
RoHS & Green
NIPDAU
Level-1-260C-UNLIM
-25 to 85
TSS721A
Samples
(1)
The marketing status values are defined as follows:
ACTIVE: Product device recommended for new designs.
LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect.
NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design.
PREVIEW: Device has been announced but is not in production. Samples may or may not be available.
OBSOLETE: TI has discontinued the production of the device.
(2)
RoHS: TI defines "RoHS" to mean semiconductor products that are compliant with the current EU RoHS requirements for all 10 RoHS substances, including the requirement that RoHS substance
do not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, "RoHS" products are suitable for use in specified lead-free processes. TI may
reference these types of products as "Pb-Free".
RoHS Exempt: TI defines "RoHS Exempt" to mean products that contain lead but are compliant with EU RoHS pursuant to a specific EU RoHS exemption.
Green: TI defines "Green" to mean the content of Chlorine (Cl) and Bromine (Br) based flame retardants meet JS709B low halogen requirements of
工商网监
湘ICP备2023018690号
