STMICROELECTRONICS TSC1031

TSC1031
High-voltage, high-side current sense amplifier
Features
■
Independent supply and input common-mode
voltages
■
Wide common-mode operating range:
2.9 to 70 V in single-supply configuration
-2.1 to 65 V in dual-supply configuration
■
Wide common-mode surviving range:
-16 to 75 V (reversed battery and load-dump
conditions)
■
Supply voltage range:
2.7 to 5.5 V in single supply configuration
■
Low current consumption: ICC max = 360 µA
■
Pin selectable gain: 50 V/V or 100 V/V
■
Buffered output
■
EMI filtering
TSSOP8
(Plastic package)
SO-8
(Plastic package)
Vm 1
8 Vp
A1 2
7 Vcc-
SEL 3
6 Gnd
Out 4
5 Vcc+
Applications
■
Automotive current monitoring
■
DC motor control
■
Photovoltaic systems
■
Battery chargers
■
Precision current sources
■
Current monitoring of notebook computers
■
Uninterruptible power supplies
■
High-end power supplies
Wide input common-mode voltage range, low
quiescent current, and tiny TSSOP8 packaging
enable use in a wide variety of applications.
Description
The TSC1031 measures a small differential
voltage on a high-side shunt resistor and
translates it into a ground-referenced output
voltage. The TSC1031’s dedicated schematic
eases the implementation of EMI filtering in harsh
environments. The gain is adjustable to 50 V/V or
100 V/V by a selection pin.
April 2011
Pin connections
(top view)
The input common-mode and power supply
voltages are independent. The common-mode
voltage can range from 2.9 to 70 V in the singlesupply configuration or be offset by an adjustable
voltage supplied on the Vcc- pin in the dualsupply configuration.
With a current consumption lower than 360 µA
and a virtually null input leakage current in
standby mode, the power consumption in the
applications is minimized.
Doc ID 16875 Rev 2
1/26
www.st.com
26
Contents
TSC1031
Contents
1
Application schematic and pin description . . . . . . . . . . . . . . . . . . . . . . 3
2
Absolute maximum ratings and operating conditions . . . . . . . . . . . . . 6
3
Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
4
Electrical characteristics curves: current sense amplifier . . . . . . . . . 10
5
Parameter definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
5.1
Common mode rejection ratio (CMR) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
5.2
Supply voltage rejection ratio (SVR) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
5.3
Gain (Av) and input offset voltage (Vos) . . . . . . . . . . . . . . . . . . . . . . . . . . 13
5.4
Output voltage drift versus temperature . . . . . . . . . . . . . . . . . . . . . . . . . . 15
5.5
Input offset drift versus temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
5.6
Output voltage accuracy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
6
Maximum permissible voltages on pins . . . . . . . . . . . . . . . . . . . . . . . . 18
7
Application information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
8
Package information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
8.1
SO-8 package information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
8.2
TSSOP-8 package information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
9
Ordering information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
10
Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
2/26
Doc ID 16875 Rev 2
TSC1031
1
Application schematic and pin description
Application schematic and pin description
The TSC1031 high-side current sense amplifier can be used in either single- or dual-supply
mode. In the single-supply configuration, the TSC1031 features a wide 2.9 V to 70 V input
common-mode range totally independent of the supply voltage. In the dual-supply range,
the common-mode range is shifted by the value of the negative voltage applied on the Vccpin. For instance, with Vcc+ = 5 V and Vcc- = -5 V, then the input common-mode range is
-2.1 V to 65 V.
Figure 1.
Single-supply configuration schematic
Vsense
Iload
Rf1
Common-mode voltage: 2.9 V to 70 V
Rf2
Cf
5V
Cf
Vp
Vm
Rg1
Rg2
Vcc
Sense
amplifier
Voltage
buffer
Vcc
SEL
GPIO
ADC
K2
TSC1031
Vcc-
Out
Rg3
Gnd
A1
Rf3
Gnd
µController
AM04523
Doc ID 16875 Rev 2
3/26
Application schematic and pin description
Figure 2.
TSC1031
Dual-supply configuration schematic
Vsense
Iload
Common-mode voltage: -2.1 V to 65 V
Rf1
Rf2
Cf
5V
Cf
Vp
Vm
Rg1
Rg2
Vcc
Sense
amplifier
Voltage
buffer
Vcc
SEL
GPIO
ADC
K2
TSC1031
Vcc-
Out
Rg3
Gnd
A1
Rf3
Gnd
µController
-5 V
AM04524
4/26
Doc ID 16875 Rev 2
TSC1031
Application schematic and pin description
Figure 3.
Common-mode versus supply voltage in dual-supply configuration
Vicm
common-mode voltage
operating range
Max = 70 V
Max = 65 V
Max = 60 V
min = 2.9 V
min = -2.1 V
Vcc- = 0 V
Vcc- = -5 V
Single-supply
min = -7.1 V
Vcc- = -10 V
Dual-supply
AM04519
Table 1 describes the function of each pin. Their position is shown in the illustration on the
cover page and in Figure 1 on page 3.
Table 1.
Pin description
Symbol
Type
Function
Out
Analog output
The Out voltage is proportional to the magnitude of the sense
voltage Vp-Vm.
Gnd
Power supply
Ground line.
Vcc+
Power supply
Positive power supply line.
Vcc-
Power supply
Negative power supply line.
Vp
Analog input
Connection for the external sense resistor. The measured current
enters the shunt on the Vp side.
Vm
Analog input
Connection for the external sense resistor. The measured current
exits the shunt on the Vm side.
SEL
Digital input
Gain-select pin.
A1
Analog output
Connection to the output resistor.
Doc ID 16875 Rev 2
5/26
Absolute maximum ratings and operating conditions
2
TSC1031
Absolute maximum ratings and operating conditions
Table 2.
Absolute maximum ratings
Symbol
Vid
Vin_sense
Parameter
Value
Unit
±20
V
-16 to 75
V
-0.3 to Vcc++0.3
V
-0.3 to Vcc++0.3
V
-0.3 to 7
V
0 to 15
V
-0.3 to Vcc++0.3
V
-55 to 150
°C
Maximum junction temperature
150
°C
TSSOP8 thermal resistance junction to ambient
120
°C/W
SO-8 thermal resistance junction to ambient
125
°C/W
HBM: human body model(3)
2.5
kV
150
V
1.5
kV
Input pins differential voltage (Vp-Vm)
(1)
Sensing pins input voltages (Vp, Vm)
Vin_sel
Gain selection pin input voltage (SEL)
Vin_A1
A1 pin input voltage(2)
Vcc+
Vcc+-Vcc-
Positive supply voltage
voltage(2)
DC output pin
Tstg
Storage temperature
Rthja
ESD
(2)
DC supply voltage
Vout
Tj
(2)
MM: machine
model(4)
(5)
CDM: charged device model
1. These voltage values are measured with respect to the Vcc- pin.
2. These voltage values are measured with respect to the Gnd pin.
3. Human body model: a 100 pF capacitor is charged to the specified voltage, then discharged through a
1.5 kΩ resistor between two pins of the device. This is done for all couples of connected pin combinations
while the other pins are floating.
4. Machine model: a 200 pF capacitor is charged to the specified voltage, then discharged directly between
two pins of the device with no external series resistor (internal resistor < 5 Ω). This is done for all couples of
connected pin combinations while the other pins are floating.
5. Charged device model: all pins plus package are charged together to the specified voltage and then
discharged directly to ground.
Table 3.
Operating conditions
Symbol
Value
Unit
2.7 to 5.5
V
Vcc+ = 5.5 V max
-8 to 0
V
Vcc+ = 3 V max
-11 to 0
V
Vicm
Common-mode voltage range referred to pin Vcc (Tmin to Tmax)
2.9 to 70
V
Toper
Operational temperature range (Tmin to Tmax)
-40 to 125
°C
Vcc+
Parameter
DC supply voltage in single-supply configuration
from Tmin to Tmax
(Vcc- connected to Gnd = 0 V)
Negative supply voltage in dual-supply
configuration from Tmin to Tmax
Vcc-
6/26
Doc ID 16875 Rev 2
TSC1031
3
Electrical characteristics
Electrical characteristics
The electrical characteristics given in the following tables are measured under the following
test conditions unless otherwise specified.
Table 4.
Symbol
●
Tamb = 25° C, Vcc+ = 5 V, Vcc- connected to Gnd (single-supply configuration).
●
Vsense = Vp-Vm = 50 mV, Vm = 12 V, no load on Out, all gain configurations.
●
Rf1, Rf2 and Rf3 resistors are short-circuited.
Supply
Parameter
Test conditions
Min.
Typ.
Max.
Unit
ICC
Total supply current
Vsense = 0 V, Tmin < Tamb < Tmax
200
360
µA
ICC1
Total supply current
Vsense = 50 mV Av = 50 V/V
Tmin < Tamb < Tmax
300
480
µA
Table 5.
Symbol
Input
Parameter
DC common-mode rejection
DC CMR Variation of Vout versus Vicm
referred to input(1)
Test conditions
Min.
Typ.
2.9 V< Vm < 70 V, Tmin < Tamb < Tmax
90
105
dB
95
dB
100
dB
AC common-mode rejection
Av = 50 V/V or 100 V/V
Variation of Vout versus Vicm
AC CMR
referred to input (peak-to-peak 2.9 V< Vicm < 30 V, 1 kHz sine wave
voltage variation)
SVR
Supply voltage rejection
Av = 50 V/V, 2.7 V< VCC < 5.5 V
Variation of Vout versus VCC(2) Vsense = 30 mV, Tmin < Tamb < Tmax
85
Vos
Input offset voltage(3)
Tamb = 25° C
Tmin < Tamb < Tmax
dVos/dT
Input offset drift vs. T
Av = 50 V/V
Tmin < Tamb < Tmax
Ilk
Input leakage current
VCC = 0 V
Tmin < Tamb < Tmax
Iib
Input bias current
Vsense = 0 V
Tmin < Tamb < Tmax
10
Rg
Input resistor value
Valid for Rg1 and Rg2
5
VIL
Logic low voltage (SEL)
VCCmin < VCC < VCCmax
VIH
Logic high voltage (SEL)
VCCmin < VCC < VCCmax
Isel
Gain-select pins (SEL)
leakage input current
SEL pin connected to GND or VCC
Tmin < Tamb < Tmax
Tmin < Tamb < Tmax
Tmin < Tamb < Tmax
-20
Max.
Unit
±500
±1100
µV
+5
µV/°C
1
µA
15
µA
kΩ
-0.3
0.5
V
1.2
VCC
V
400
nA
1. See Chapter 5: Parameter definitions on page 13 for the definition of CMR.
2. See Chapter 5 for the definition of SVR.
3. See Chapter 5 for the definition of Vos.
Doc ID 16875 Rev 2
7/26
Electrical characteristics
Table 6.
Symbol
TSC1031
Output
Parameter
Test conditions
Min.
Typ.
K1
Sense amplifier gain
(K1 = Rg3/Rg1)
K2
Current multiplier gain
SEL= Gnd
SEL= Vcc+
2.5
5
Av
Total gain (Av = 2.K1.K2)
SEL= Gnd
SEL= Vcc+
50
100
Output voltage drift vs. T(1)
Av = 50 V/V
Tmin < Tamb < Tmax
ΔVout/ΔT
ΔVout/ΔIout Output stage load regulation
Max.
Unit
10
-10 mA < Iout <10 mA
Iout sink or source current
Av = 50 V/V, Tamb = 25° C
0.3
V/V
±240
ppm/°C
±1.5
mV/mA
Total output voltage accuracy(2)
Vsense = 50 mV(3)
Tamb = 25° C
Tmin < Tamb < Tmax
±2.5
±4
%
ΔVout
Total output voltage accuracy
Vsense = 90 mV(3)
Tamb = 25° C
Tmin < Tamb < Tmax
±3.5
±5
%
ΔVout
Total output voltage accuracy
Vsense = 20 mV Tamb = 25° C
Tmin < Tamb < Tmax
±3.5
±5
%
ΔVout
Total output voltage accuracy
Vsense = 10 mV Tamb = 25° C
Tmin < Tamb < Tmax
±5.5
±8
%
ΔVout
Total output voltage accuracy
Vsense = 5 mV Tamb = 25° C
Tmin < Tamb < Tmax
±10
±22
%
Short-circuit current
OUT connected to VCC or
GND
VOH
Output stage high-state saturation
voltage
VOH = VCC-Vout
Vsense = 1 V
Iout = 1 mA
85
135
mV
VOL
Output stage low-state saturation
voltage
Vsense = -1 V
Iout = 1 mA
80
125
mV
ΔVout
Isc
15
26
mA
1. See Chapter 5: Parameter definitions on page 13 for the definition of output voltage drift versus temperature.
2. The output voltage accuracy is the difference with the expected theoretical output voltage Vout-th = Av*Vsense. See Chapter 5
for a more detailed definition.
3. Except for Av = 100 V/V.
8/26
Doc ID 16875 Rev 2
TSC1031
Table 7.
Electrical characteristics
Frequency response
Symbol
Parameter
Test conditions
Min.
Typ.
Max.
Unit
Vsense = 10 mV to 100 mV,
Cload = 47 pF
ts
Output settling to 1% of final value
Av = 50 V/V
6
µs
Av = 100 V/V
10
µs
tSEL
Output settling to 1% of final value
Any change of state of SEL
1
µs
trec
Response to common-mode
voltage change.
Output settling to 1% of final value
Vcc+= 5 V, Vcc-= -5 V
Vm step change from -2 V to
30 V or 30 V to -2 V
20
µs
SR
Slew rate
Vsense = 10 mV to 100 mV
0.6
V/µs
BW
3 dB bandwidth
Cload = 47 pF Vicm = 12 V
Vsense = 50 mV
Av = 50 V/V
700
kHz
Table 8.
Symbol
eN
0.4
Noise
Parameter
Equivalent input noise voltage
Test conditions
f = 1 kHz
Doc ID 16875 Rev 2
Min.
Typ.
40
Max.
Unit
nV/√ Hz
9/26
Electrical characteristics curves: current sense amplifier
4
TSC1031
Electrical characteristics curves: current sense
amplifier
Unless otherwise specified, the test conditions for the following curves are:
Figure 4.
●
Tamb = 25°C, VCC = 5 V, Vsense = Vp - Vm = 50 mV, Vm = 12 V.
●
No load on Out pin.
Output voltage vs. Vsense
Figure 5.
Output voltage accuracy vs. Vsense
25
6
20
5
10
delta in (%)
4
Vout (V)
Guaranteed
accuracy vs. T
Typical
accuracy
15
3
2
1
5
0
-5
-10
Guaranteed
accuracy @ 25 °C
-15
-20
0
-25
-20
0
20
40
60
80
100
120
0
20
Vsense (mV)
Figure 6.
350
40
60
80
100
Vsense (mV)
Supply current vs. supply voltage
Figure 7.
Supply current vs. Vsense
400
T = -40 °C
300
350
250
300
T = 25 °C
250
200
T = 25 °C
Icc (µA)
Icc (µA)
T = -40 °C
T = 125 °C
150
200
T = 125 °C
150
100
100
50
50
0
0
-100
2.5
3
3.5
4
4.5
5
5.5
Vcc (V)
10/26
Doc ID 16875 Rev 2
-50
0
Vsense (mV)
50
100
TSC1031
Electrical characteristics curves: current sense amplifier
Figure 8.
Vp pin input current vs. Vsense
Figure 9.
40
35
T = 25 °C
30
T = -40 °C
20
Im (µA)
Ip (µA)
25
15
10
5
T = 125 °C
0
-100
-50
0
50
Vn pin input current vs. Vsense
20
18
16
14
12
10
8
6
4
2
0
T = 25 °C
T = 125 °C
-100
100
T = -40 °C
-50
Figure 10. Output stage low-state saturation
voltage vs. output current
(Vsense = -1 V)
Figure 11.
1200
1200
Output stage
sinking current
T = 125 °C
Output stage
sourcing current
800
Voh (mV)
T = 125 °C
Vol (mV)
100
Output stage high-state saturation
voltage vs. output current
(Vsense = +1 V)
1000
800
600
400
T = 25 °C
200
600
400
T = -40 °C
T = 25 °C
200
T = -40 °C
0
0
0
2
4
6
8
10
-10
Iout (mA)
Figure 12.
Vout - (Vout @ Iout = 0A) (mV)
50
Vsense (mV)
Vsense (mV)
1000
0
-6
-4
-2
0
Iout (mA)
Output stage load regulation
1
-8
Figure 13. Step response
T = -40 °C
0
Vsense
-1
T = 125 °C
T = 25 °C
-2
-3
-4
-5
Output stage
sourcing current
Output stage
sinking current
Vout
-6
-10
-5
0
5
10
Iout (mA)
Doc ID 16875 Rev 2
Time base
4µs/div
Vsense
50mV/div
Vout 500mV/div
11/26
Electrical characteristics curves: current sense amplifier
Figure 14. Bode diagram
TSC1031
Figure 15. Power supply rejection ratio
30
50
45
20
40
35
10
PSRR (dB)
Gain (dB)
30
0
-10
-20
20
15
10
5
0
-30
1.E+03
25
1.E+04
1.E+05
1.E+06
1.E+07
1.E+01
Figure 16. Noise Level
120
Noise level (nv/sqrt(Hz))
100
80
60
40
20
0
Frequency (Hz)
12/26
1.E+02
1.E+03
1.E+04
Frequency (Hz)
Frequency (Hz)
Doc ID 16875 Rev 2
1.E+05
1.E+06
TSC1031
Parameter definitions
5
Parameter definitions
5.1
Common mode rejection ratio (CMR)
The common mode rejection ratio (CMR) measures the ability of the current sensing
amplifier to reject any DC voltage applied on both inputs Vp and Vm. The CMR is referred
back to the input so that its effect can be compared with the applied differential signal. The
CMR is defined by the formula:
ΔV out
CMR = – 20 ⋅ log -----------------------------ΔV icm ⋅ Av
5.2
Supply voltage rejection ratio (SVR)
The supply voltage rejection ratio (SVR) measures the ability of the current-sensing
amplifier to reject any variation of the supply voltage VCC. The SVR is referred back to the
input so that its effect can be compared with the applied differential signal. The SVR is
defined by the formula:
ΔV out
SVR = – 20 ⋅ log ----------------------------ΔV CC ⋅ Av
5.3
Gain (Av) and input offset voltage (Vos)
The input offset voltage is defined as the intersection between the linear regression of the
Vout vs. Vsense curve with the X-axis (see Figure 17.). If Vout1 is the output voltage with
Vsense = Vsense1 and Vout2 is the output voltage with Vsense = Vsense2, then Vos can be
calculated with the following formula.
V sense1 – V sense2
V os = V sense1 – ⎛ ------------------------------------------------ ⋅ V out1⎞
⎝ V out1 – V out2
⎠
Doc ID 16875 Rev 2
13/26
Parameter definitions
TSC1031
Figure 17. Vout versus Vsense characteristics: detail for low Vsense values
Vout
Vout_1
Vout_2
Vsense
Vos
Vsense2
Vsense1
AM04520
The values of Vsense1 and Vsense2 used for the input offset calculations are detailed in
Table 9.
Table 9.
14/26
Test conditions for Vos voltage calculation
Av (V/V)
Vsense1 (mV)
Vsense2 (mV)
50
50
5
100
40
5
Doc ID 16875 Rev 2
TSC1031
Output voltage drift versus temperature
The output voltage drift versus temperature is defined as the maximum variation of Vout with
respect to its value at 25° C over the temperature range. It is calculated as follows:
ΔV out
V out ( T amb ) – V out ( 25° C )
----------------- = max -------------------------------------------------------------------------ΔT
T amb – 25° C
with Tmin < Tamb < Tmax.
Figure 18 provides a graphical definition of the output voltage drift versus temperature. On
this chart Vout is always within the area defined by the maximum and minimum variation of
Vout versus T, and T = 25° C is considered to be the reference.
Figure 18. Output voltage drift versus temperature (Av = 50 V/V Vsense = 50 mV)
60
40
[email protected]°C (mV)
5.4
Parameter definitions
20
0
-20
-40
-60
-60
-40
-20
0
20
40 60
T (°C)
Doc ID 16875 Rev 2
80
100 120 140
15/26
Parameter definitions
5.5
TSC1031
Input offset drift versus temperature
The input voltage drift versus temperature is defined as the maximum variation of Vos with
respect to its value at 25° C over the temperature range. It is calculated as follows:
ΔV os
V os ( T amb ) – V os ( 25° C )
--------------- = max --------------------------------------------------------------------ΔT
T amb – 25° C
with Tmin < Tamb < Tmax.
Figure 19. provides a graphical definition of the input offset drift versus temperature. On this
chart Vos is always comprised in the area defined by the maximum and minimum variation of
Vos versus T, and T = 25° C is considered to be the reference.
Figure 19. Input offset drift versus temperature (Av = 50 V/V)
1.5
[email protected]°C (mV)
1
0.5
0
-0.5
-1
-1.5
-2
-2.5
-60 -40 -20
5.6
0
20
40 60
T (°C)
80
100 120 140
Output voltage accuracy
The output voltage accuracy is the difference between the actual output voltage and the
theoretical output voltage. Ideally, the current sensing output voltage should be equal to the
input differential voltage multiplied by the theoretical gain, as in the following formula.
Vout-th = Av. Vsense
The actual value is very slightly different, mainly due to the effects of:
16/26
●
the input offset voltage Vos,
●
the non-linearity.
Doc ID 16875 Rev 2
TSC1031
Parameter definitions
Figure 20. Vout vs. Vsense theoretical and actual characteristics
Vout
Actual
Ideal
Vout accuracy for Vsense = 5 mV
Vsense
5 mV
AM04521
The output voltage accuracy, expressed as a percentage, can be calculated with the
following formula,
abs ( V out – ( Av ⋅ V sense ) )
ΔV out = -------------------------------------------------------------------------Av ⋅ V sense
with 50 V/V or 100 V/V depending on the configuration of the SEL pin.
Doc ID 16875 Rev 2
17/26
Maximum permissible voltages on pins
6
TSC1031
Maximum permissible voltages on pins
The TSC1031 can be used in either single or dual supply configuration. The dual-supply
configuration is achieved by disconnecting Vcc- and Gnd, and connecting Vcc- to a negative
supply. Figure 21 illustrates how the absolute maximum voltages on input pins Vp and Vm
are referred to the Vcc- potential, while the maximum voltages on the positive supply pin,
gain selection pins and output pins are referred to the Gnd pin. It should also be noted that
the maximum voltage between Vcc- and Vcc+ is limited to 15 V.
Figure 21. Maximum voltages on pins
Vp and Vm
+75 V
SEL and Out
Vcc-
Vcc+
Vcc+
+15 V
+7 V
Vcc+
+ 0.3 V
Gnd
Gnd
-0.3V
-0.3 V
Vcc+
SEL and Out
Vcc-
-16 V
Vp and Vm
AM04528
18/26
Doc ID 16875 Rev 2
TSC1031
Application information
The TSC1031 can be used to measure current and to feed back the information to a
microcontroller.
Figure 22. Typical application
Vsense
Iload
Common-mode voltage: 2.9 V to 70 V
Rsense
load
7
Application information
Rf1
Rf2
Vp
Vm
5V
Vcc
Rg1
5K
Vcc+
Rg2
SEL
Sense
amplifier
Current
multiplier
K2
2.5 or 5
Vout
x2
TSC1031
Rg3
50K
ADC
Out
A1
Vcc-
GPIO
Gnd
Gnd
µController
Rf3
AM06157
The current from the supply flows to the load through the Rsense resistor causing a voltage
drop equal to Vsense across Rsense. The amplifier’s input currents are negligible, therefore its
inverting input voltage is equal to Vm. The amplifier's open-loop gain forces its non-inverting
input to the same voltage as the inverting input. As a consequence, the amplifier adjusts
current flowing through Rg1 so that the voltage drop across Rg1 exactly matches Vsense.
Therefore, the drop across Rg1 is:
VRg1 = Vsense = Rsense.Iload
If IRg1 is the current flowing through Rg1, then IRg1 is given by the formula:
IRg1 = Vsense/Rg1
The IRg1 current flows is multiplied by a ratio K2 and the resulting current flows into resistor
Rg3. Therefore, the voltage drop on the Rg3 resistor can be calculated as follows.
VRg3 = Rg3.K2.IRg1 = (Rg3/Rg1).K2.Vsense= K1.K2.Vsense with K1=Rg3/Rg1=10.
The voltage across the Rg3 resistor is buffered to the Out pin by the voltage buffer, featuring
a gain equal to 2. Therefore Vout can be expressed as:
Vout = 2.K1.K2.Vsense = Av .Vsense with Av= 2.K1.K2
or: Vout = Av .Rsense.Iload
Doc ID 16875 Rev 2
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Application information
TSC1031
The current multiplier gain K2 can be set to 2.5 or 5 depending on the voltage applied on the
SEL pin.
Since they define the full-scale output range of the application, the Rsense resistor and the
amplification gain Av are important parameters and must therefore be selected carefully.
The TSC1031’s dedicated schematic eases the implementation of EMI filtering in harsh
environments. A simple filter is described in Figure 22, where the input filtering is performed
by Rf1, Rf2 and Cf.
The values of Rf1 and Rf2 should be equal so as to balance the contribution on both
amplifier inputs. The value of the Cf capacitor should be selected so that the cut-off
frequency of the first-order low-pass filter provides enough attenuation to the high frequency
interferences.
To balance the contribution of Rf1 and Rf2 in the current sense amplifier gain, an output
resistor Rf3 should be connected between pin A1 and Gnd. The value of Rf3 should be
chosen according to the following formula.
K1 = 10 = Rg3/Rg1= Rf3/Rf1 = Rf3/Rf2
If these precautions having been taken, the TSC1031’s gain is unaffected by the
implementation of the input filtering resistors.
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TSC1031
8
Package information
Package information
In order to meet environmental requirements, ST offers these devices in different grades of
ECOPACK® packages, depending on their level of environmental compliance. ECOPACK®
specifications, grade definitions and product status are available at: www.st.com.
ECOPACK® is an ST trademark.
Doc ID 16875 Rev 2
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Package information
8.1
TSC1031
SO-8 package information
Figure 23. SO-8 package mechanical drawing
Table 10.
SO-8 package mechanical data
Dimensions
Ref.
Millimeters
Min.
Typ.
A
Max.
Min.
Typ.
1.75
0.25
Max.
0.069
A1
0.10
A2
1.25
b
0.28
0.48
0.011
0.019
c
0.17
0.23
0.007
0.010
D
4.80
4.90
5.00
0.189
0.193
0.197
E
5.80
6.00
6.20
0.228
0.236
0.244
E1
3.80
3.90
4.00
0.150
0.154
0.157
e
0.004
0.010
0.049
1.27
0.050
h
0.25
0.50
0.010
0.020
L
0.40
1.27
0.016
0.050
L1
k
ccc
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Inches
1.04
0
0.040
8°
0.10
Doc ID 16875 Rev 2
1°
8°
0.004
TSC1031
8.2
Package information
TSSOP-8 package information
Figure 24. TSSOP8 package mechanical drawing
Table 11.
TSSOP8 package mechanical data
Dimensions
Ref.
Millimeters
Min.
Typ.
A
Inches
Max.
Min.
Typ.
1.20
A1
0.05
A2
0.80
b
Max.
0.047
0.15
0.002
1.05
0.031
0.19
0.30
0.007
0.012
c
0.09
0.20
0.004
0.008
D
2.90
3.00
3.10
0.114
0.118
0.122
E
6.20
6.40
6.60
0.244
0.252
0.260
E1
4.30
4.40
4.50
0.169
0.173
0.177
e
0.65
k
0°
L
0.45
L1
aaa
1.00
0.60
0.006
0.039
0.041
0.0256
8°
0°
0.75
0.018
1
8°
0.024
0.030
0.039
0.10
Doc ID 16875 Rev 2
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Ordering information
TSC1031
9
Ordering information
Table 12.
Order codes
Part number
Temperature range
TSC1031IPT
Package
Packaging
Marking
TSSOP8
Tape & reel
1031I
SO-8
Tape & reel
TSC1031I
TSSOP8(1)
Tape & reel
1031Y
Tape & reel
TSC1031Y
-40°C, +125°C
TSC1031IDT
TSC1031IYPT
TSC1031IYDT
-40°C, +125°C
Automotive grade
SO-8
(2)
1. Qualification and characterization according to AEC Q100 and Q003 or equivalent, advanced screening according to AEC
Q001 & Q002 or equivalent are on-going.
2. Qualification and characterization according to AEC Q100 and Q003 or equivalent, advanced screening according to AEC
Q001 & Q002 or equivalent.
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TSC1031
10
Revision history
Revision history
Table 13.
Document revision history
Date
Revision
04-Jan-2010
1
Initial release.
2
Added Chapter 4: Electrical characteristics curves: current
sense amplifier.
Changed Figure 4 to Figure 16.
Modified Figure 22: Typical application.
Added automotive grade qualification for SO-8 package in
Table 12: Order codes.
29-Apr-2011
Changes
Doc ID 16875 Rev 2
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TSC1031
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