STMICROELECTRONICS TSC101AILT

TSC101
High side current sense amplifier
Target Specification
Features
■
Independent supply and input common-mode
voltages
■
Wide common-mode operating range: 2.8 to
30V
■
Wide common-mode surviving range: -0.3 to
60V (load-dump)
■
Wide supply voltage range: 4 to 28V
■
Low current consumption: ICC max = 300µA
■
Internally fixed gain: 20V/V, 50V/V or 100V/V
■
Buffered output
L
SOT23-5
(Plastic package)
Pin connections
(top view)
Applications
Out 1
■
Battery chargers
■
Automotive current monitoring
■
Notebook computers
■
DC motor control
■
Precision current sources
5 Vcc
Gnd 2
Vp 3
4 Vm
Description
The TSC101 measures a small differential voltage
on a high-side shunt resistor and translates it into
a ground-referenced output voltage. The gain is
internally fixed.
Wide input common-mode voltage range, low
quiescent current, and tiny SOT23 packaging
enable use in a wide variety of applications.
Input common-mode and power supply voltages
are independent. Common-mode voltage can
range from 2.8V to 30V in operating conditions
and up to 60V in absolute maximum ratings.
Current consumption lower than 300µA and wide
supply voltage range allow to connect the power
supply to either side of the current measurement
shunt with minimal error.
March 2007
Rev 1
This is preliminary information on a new product foreseen to be developed. Details are subject to change without notice.
1/18
www.st.com
18
Contents
TSC101
Contents
1
Application schematic and pin description . . . . . . . . . . . . . . . . . . . . . . 3
2
Absolute maximum ratings and operating conditions . . . . . . . . . . . . . 4
3
Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
4
Parameter definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Common mode rejection ratio (CMR) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Supply voltage rejection ratio (SVR) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Gain (Av) and input offset voltage (Vos) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Output voltage drift versus temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Output voltage accuracy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Output voltage range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
5
Application information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
6
Package information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
7
Ordering information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
8
Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
2/18
TSC101
1
Application schematic and pin description
Application schematic and pin description
The TSC101 high-side current-sense amplifier features a 2.8V to 30V input common-mode
range that is independent of supply voltage. The main advantage of this feature is to allow
high-side current sensing at voltages much greater than the supply voltage (VCC).
Figure 1.
Application schematic
Vsense
Iload
2.8V to 30V
Rsense
3
5
load
4
Vp
Vm
Rg1
Rg2
VCC
1
Rg3
Out
Vout=Av.Vsense
Gnd
2
Table 1 below describes the function of each pin. Their position is shown in the illustration
on the cover page and in Figure 1 above.
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.
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.
3/18
Absolute maximum ratings and operating conditions
2
TSC101
Absolute maximum ratings and operating conditions
Table 2.
Absolute maximum ratings
Symbol
Vid
Vi
Parameter
Input pins differential voltage (Vp-Vm)
Input pin voltages (Vp, Vm)
(1)
(1)
Value
Unit
±60
V
-0.3 to 60
V
VCC
DC supply voltage
-0.3 to 30
V
Vout
DC output pin voltage(1)
-0.3 to 28
V
Tstg
Storage temperature
-55 to 150
°C
150
°C
2
kV
200
V
Tj
ESD(2)
Maximum junction temperature
Human body model (HBM)
Machine model (MM)
1. Voltage values are measured with respect to the GND pin.
2. ESD test for each couple of pins.
Table 3.
Symbol
4/18
Operating conditions
Parameter
Value
Unit
VCC
DC supply voltage from Tmin to Tmax
4.0 to 28
V
Toper
Operational temperature range (Tmin to Tmax)
-40 to 125
°C
Rthja
SOT23-5 thermal resistance junction to ambient
250
°C/W
TSC101
3
Electrical characteristics
Electrical characteristics
The electrical characteristics given in the following tables are measured under the following
test conditions unless otherwise specified:
Tamb=25°C, VCC=12V, Vsense=Vp-Vm=50mV, Vm=12V, no load on Out
Table 4.
Supply
Symbol
ICC
Table 5.
Symbol
Vicm
Parameter
Total supply current
Test conditions
Typ.
Vsense = 0
Tmin < Tamb < Tmax
Max.
Unit
300
µA
Max.
Unit
30
V
Input
Parameter
Common mode voltage range
DC common mode rejection
DC CMR Variation of Vout versus Vicm
referred to input(1)
AC common mode rejection
versus Vicm
AC CMR Variation of Vout
referred to input (peak-to-peak
voltage variation)
Test conditions
Min.
Tmin < Tamb < Tmax
2.8
2.8V< Vicm < 30V
Tmin < Tamb < Tmax
90
Typ.
105
dB
2.8V< Vicm < 30V
1kHz sine wave
95
dB
2.8V< Vicm < 30V
10kHz sine wave
80
dB
105
dB
Supply voltage rejection
Variation of Vout versus VCC(2)
4.0V< VCC < 28V
Vsense=30mV
Tmin < Tamb < Tmax
Vos
Input offset voltage(3)
Tamb=25° C
Tmin < Tamb < Tmax
dVos/dT
Input offset drift vs. T
Tmin < Tamb < Tmax
Ilk
Input leakage current
VCC=0V
Tmin < Tamb < Tmax
Iib
Input bias current
Vsense=0V
Tmin < Tamb < Tmax
SVR
Min.
90
±0.2
±0.9
0
5.5
±1.5
±2.3
mV
4.5
µV/°C
1
µA
8
µA
1. See Section 4: Parameter definitions on page 8 for the definition of CMR.
2. See Section 4: Parameter definitions on page 8 for the definition of SVR.
3. See Section 4: Parameter definitions on page 8 for the definition of Vos.
5/18
Electrical characteristics
Table 6.
TSC101
Output
Symbol
Parameter
Test conditions
Av
Gain
TSC101A
TSC101B
TSC101C
ΔAv
Gain accuracy
Tamb=25°C
Tmin < Tamb < Tmax
Output voltage drift vs. T(1)
Tmin < Tamb < Tmax
ΔVout/ΔT
ΔVout/ΔIout Output stage load regulation
Min.
Typ.
Max.
20
50
100
-600
-10mA < Iout <1 0mA
Iout sink or source current
Unit
V/V
±3
±5
%
-300
0
µV/°C
2
tbd
mV/mA
tbd
tbd
%
ΔVout
Total output voltage accuracy(2)
Vsense=10mV Tamb=25° C
Tmin < Tamb < Tmax
ΔVout
Total output voltage accuracy
Vsense=20mV Tamb=25° C
Tmin < Tamb < Tmax
ΔVout
Total output voltage accuracy
Vsense=50mV Tamb=25° C
Tmin < Tamb < Tmax
ΔVout
Total output voltage accuracy
Vsense=100mV Tamb=25° C
Tmin < Tamb < Tmax
Short-circuit current
OUT connected to VCC or
GND
VOH
Output stage high-state saturation
voltage
VOH=VCC-Vout
Vsense=1V
Iout=1mA
0.8
1
V
VOL
Output stage low-state saturation
voltage
Vsense=-1V
Iout=1mA
50
100
mV
Isc
15
tbd
tbd
%
tbd
tbd
%
tbd
tbd
%
40
mA
1. See Section 4: Parameter definitions on page 8 for the definition of output voltage drift versus temperature.
2. Output voltage accuracy is the difference with the expected theoretical output voltage Vout-th=Av*Vsense. See Section 4:
Parameter definitions on page 8 for a more detailed definition.
6/18
TSC101
Table 7.
Electrical characteristics
Frequency response
Symbol
Parameter
Test conditions
Min.
Typ.
Max.
Unit
Vsense=10mV to 100mV,
Cload=47pF
ts
SR
Output settling to 1% final value
TSC101A
3
µs
TSC101B
6
µs
TSC101C
10
µs
0.9
V/µs
TSC101A
650
kHz
TSC101B
710
kHz
TSC101C
540
kHz
Vsense=10mV to 100mV
Slew rate
0.55
Cload=47pF Vicm=12V
Vsense=100mV
BW
Table 8.
Symbol
3dB bandwidth
Noise
Parameter
Total output voltage noise
Test conditions
Min.
Typ.
50
Max.
Unit
nV/√ Hz
7/18
Parameter definitions
4
TSC101
Parameter definitions
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
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
8/18
TSC101
Parameter definitions
Gain (Av) and input offset voltage (Vos)
The input offset voltage is defined as the intersection between the linear regression of Vout
vs. Vsense curve with the X-axis (see Figure 2). If Vout1 is the output voltage with
Vsense=Vsense1=50mV and Vout2 is the output voltage with Vsense=Vsense2=5mV, then Vos
can be calculated with the following formula:
V sense1 – V sense2
V os = V sense1 – ⎛ ------------------------------------------------ ⋅ V out1⎞
⎝ V out1 – V out2
⎠
The amplification gain Av is defined as the ratio between output voltage and input differential
voltage:
V out
Av = ----------------V sense
Figure 2.
Vout versus Vsense characteristics: detail for low Vsense values
Vout
V0
5mV
50mV
Vsense
9/18
Parameter definitions
TSC101
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 3 provides a graphical definition of output voltage drift versus temperature. On this
chart, Vout is always comprised in the grey area defined by the maximum and minimum
variation of Vout vs. T, and T=25°C is considered to be the reference.
Figure 3.
Output voltage drift versus temperature
Output voltage drift vs. temperature
4.58
4.56
Vout (V)
4.54
4.52
4.5
4.48
4.46
4.44
-50
10/18
-25
0
25
50
Temperature (°C)
75
100
125
TSC101
Parameter definitions
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:
●
the input offset voltage Vos,
●
non-linearity,
●
VOL and VOH voltage saturation (see Figure 5 on page 12)
Figure 4.
Vout vs. Vsense theoretical and actual characteristics
Vout
actual
ideal
Vsense
5mV
The output voltage accuracy, expressed in percentage, can be calculated with the following
formula:
abs ( V out – ( Av ⋅ V sense ) )
ΔV out = -------------------------------------------------------------------------Av ⋅ V sense
with Av=20V/V for TSC101A, Av=50V/V for TSC101B and Av=100V/V for TSC101C.
11/18
Parameter definitions
TSC101
Output voltage range
The output voltage versus input differential voltage is linear in a range of output voltage
limited by high-level and low-level saturation voltage.
Figure 5.
Vout vs. Vsense over the full voltage range
Vout
VCC
VOH
VOL
Vsense
12/18
TSC101
5
Application information
Application information
TSC101 can be used to measure current and to feed back the information to a micro
controller, as shown in Figure 6 below.
Figure 6.
Typical application schematic
Vsense
Iload
2.8V to 30V
Rsense
load
Vp
V
Rg1
Rg2
TSC101
5V
Vreg
VCC
VCC
ADC
Rg3
Out
Vout
GND
Microcontroller
GND
The current from the supply flows to the load through the Rsense resistor causing a voltage
drop equal to Vsense across Rsense. The amplifier 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 will adjust
current flowing through Rg1 so that the voltage drop across Rg1 will exactly match 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 entirely into resistor Rg3 (the input bias current of the buffer is
negligible). Therefore, the voltage drop on the Rg3 resistor can be calculated as follows:
VRg3=Rg3.IRg1=(Rg3/Rg1).Vsense
13/18
Application information
TSC101
Because the voltage across the Rg3 resistor is buffered to the Out pin, Vout can be
expressed as:
Vout=(Rg3/Rg1).Vsense
or
Vout=(Rg3/Rg1).Rsense.Iload
The resistor ratio Rg3/Rg1 is internally set to 20V/V for TSC101A, to 50V/V for TSC101B and
to 100V/V for TSC101C.
Because they define the full scale output range of your application, the Rsense resistor and
the Rg3/Rg1 resistor ratio (equal to Av) are important parameters, and therefore must be
selected carefully.
14/18
TSC101
6
Package information
Package information
In order to meet environmental requirements, STMicroelectronics offers these devices in
ECOPACK® packages. These packages have a lead-free second level interconnect. The
category of second level interconnect is marked on the package and on the inner box label,
in compliance with JEDEC Standard JESD97. The maximum ratings related to soldering
conditions are also marked on the inner box label. ECOPACK is an STMicroelectronics
trademark. ECOPACK specifications are available at: www.st.com.
Figure 7.
SOT23-5 package
Dimensions
Ref.
Millimeters
Min.
Typ.
Mils
Max.
Min.
Typ.
Max.
A
0.90
1.45
35.4
57.1
A1
0.00
0.15
0.00
5.9
A2
0.90
1.30
35.4
51.2
b
0.35
0.50
13.7
19.7
C
0.09
0.20
3.5
7.8
D
2.80
3.00
110.2
118.1
E
2.60
3.00
102.3
118.1
E1
1.50
1.75
59.0
68.8
e
0.95
37.4
e1
1.9
74.8
L
0.35
0.55
13.7
21.6
15/18
Ordering information
TSC101
7
Ordering information
Table 9.
Order codes
Part number
Temperature range
Package
Packaging
TSC101AILT
TSC101BILT
-40°C, +125°C
SOT23-5
Tape & reel
TSC101CILT
(1)
TSC101AIYLT
(1)
TSC101BIYLT
TSC101CIYLT(1)
-40°C, +125°C
automotive grade
SOT23-5
Tape & reel
Marking
Gain
O104
20
O105
50
O106
100
O101
20
O102
50
O103
100
1. Qualified and characterized according to AEC Q100 and Q003 or equivalent, advanced screening according to AEC Q001
& Q 002 or equivalent.
16/18
TSC101
8
Revision history
Revision history
Date
Revision
5-Mar-2007
Rev 1
Changes
First release, preliminary data.
17/18
TSC101
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