tsx711

TSX711, TSX712
Low-power, precision, rail-to-rail, 2.7 MHz, 16 V CMOS
operational amplifiers
Datasheet - production data
See the TSX921 and TSX922 for higher
speeds
Applications
Battery-powered instrumentation
Instrumentation amplifier
Active filtering
DAC buffer
High-impedance sensor interface
Current sensing (high and low side)
Description
Features
Low input offset voltage: 200 µV max.
Rail-to-rail input and output
Low current consumption: 800 µA max.
Gain bandwidth product: 2.7 MHz
Low supply voltage: 2.7 - 16 V
Unity gain stable
Low input bias current: 50 pA max.
High ESD tolerance: 4 kV HBM
Extended temp. range: -40 °C to 125 °C
Automotive qualification
Related products
See the TSX7191 and TSX7192 for higher
speeds with similar precision
See the TSX561 and TSX562 for low-power
features
See the TSX631 and TSX632 for micropower features
January 2016
The TSX711 and TSX712 series of operational
amplifiers (op amps) offer high precision
functioning with low input offset voltage down to a
maximum of 200 µV at 25 °C. In addition, their
rail-to-rail input and output functionality allow
these products to be used on full range input and
output without limitation. This is particularly useful
for a low-voltage supply such as 2.7 V that the
TSX71x is able to operate with.
Thus, the TSX71x has the great advantage of
offering a large span of supply voltages, ranging
from 2.7 V to 16 V. They can be used in multiple
applications with a unique reference.
Low input bias current performance makes the
TSX71x perfect when used for signal conditioning
in sensor interface applications. In addition, lowside and high-side current measurements can be
easily made thanks to rail-to-rail functionality.
High ESD tolerance (4 kV HBM) and a wide
temperature range are also good arguments to
use the TSX71x in the automotive market
segment.
DocID025959 Rev 4
This is information on a product in full production.
1/30
www.st.com
Contents
TSX711, TSX712
Contents
1
Package pin connections................................................................ 3
2
Absolute maximum ratings and operating conditions ................. 4
3
4
Electrical characteristics ................................................................ 5
Electrical characteristic curves .................................................... 11
5
Application information ................................................................ 17
6
5.1
Operating voltages .......................................................................... 17
5.2
Input pin voltage ranges .................................................................. 17
5.3
Rail-to-rail input ............................................................................... 17
5.4
Rail-to-rail output ............................................................................. 17
5.5
Input offset voltage drift over temperature ....................................... 18
5.6
Long term input offset voltage drift .................................................. 18
5.7
High values of input differential voltage ........................................... 19
5.8
Capacitive load................................................................................ 20
5.9
PCB layout recommendations ......................................................... 21
5.10
Optimized application recommendation .......................................... 21
5.11
Application examples ...................................................................... 21
5.11.1
Oxygen sensor ................................................................................. 21
5.11.2
Low-side current sensing.................................................................. 22
Package information ..................................................................... 24
6.1
SOT23-5 package information ........................................................ 25
6.2
MiniSO8 package information ......................................................... 26
6.3
SO8 package information ................................................................ 27
7
Ordering information..................................................................... 28
8
Revision history ............................................................................ 29
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DocID025959 Rev 4
TSX711, TSX712
1
Package pin connections
Package pin connections
Figure 1: Pin connections (top view)
DocID025959 Rev 4
3/30
Absolute maximum ratings and operating
conditions
2
TSX711, TSX712
Absolute maximum ratings and operating conditions
Table 1: Absolute maximum ratings (AMR)
Symbol
VCC
Parameter
Supply voltage
(1)
Vid
Differential input voltage
Vin
Input voltage
Iin
Input current
(2)
(3)
Tstg
Storage temperature
Rthja
Thermal resistance junction to
(4)(5)
ambient
Tj
ESD
MM: machine model
Unit
18
V
±VCC
mV
(VCC-) - 0.2 to (VCC+) + 0.2
V
10
mA
-65 to 150
°C
SOT23-5
250
MiniSO8
190
SO8
125
Maximum junction temperature
HBM: human body model
Value
150
(6)
°C/W
°C
4000
(7)
100
CDM: charged device model
(8)
V
1500
Latch-up immunity
200
mA
Notes:
(1)
All voltage values, except the differential voltage are with respect to the network ground terminal.
(2)
Differential voltages are the non-inverting input terminal with respect to the inverting input terminal. See Section
5.7 for the precautions to follow when using the TSX711 and TSX712 with a high differential input voltage.
(3)
(4)
(5)
(6)
(7)
(8)
Input current must be limited by a resistor in series with the inputs.
Rth are typical values.
Short-circuits can cause excessive heating and destructive dissipation.
According to JEDEC standard JESD22-A114F.
According to JEDEC standard JESD22-A115A.
According to ANSI/ESD STM5.3.1
Table 2: Operating conditions
Symbol
4/30
Parameter
VCC
Supply voltage
Vicm
Common mode input voltage range
Toper
Operating free air temperature range
Value
2.7 to 16
DocID025959 Rev 4
(VCC-) - 0.1 to (VCC+) + 0.1
-40 to 125
Unit
V
°C
TSX711, TSX712
3
Electrical characteristics
Electrical characteristics
Table 3: Electrical characteristics at VCC+ = 4 V with VCC- = 0 V, Vicm = VCC/2, Tamb = 25 ° C,
and RL > 10 kΩ connected to VCC/2 (unless otherwise specified)
Symbol
Parameter
Conditions
Vio
(TSX711,
TSX712)
Input offset voltage
Vio
(TSX711A)
ΔVio/ΔT
ΔVio
Iib
Input offset voltage drift
(1)
Iio
Input offset current
RIN
Input resistance
CIN
Input capacitance
(1)
Common mode rejection
ratio 20 log (ΔVic/ΔVio)
CMRR
(TSX712)
Large signal voltage gain
200
Tmin < Top < 85 °C
365
Tmin < Top < 125 °C
450
Vicm = VCC/2
100
Tmin < Top < 85 °C
265
Tmin < Top < 125 °C
350
2.5
High level output voltage
(voltage drop from VCC+)
Unit
μV
µV/°C
nV
month
---------------------------
T = 25 °C
1
Vout = VCC/2
1
1
Tmin < Top < Tmax
84
Tmin < Top < Tmax
83
Vicm = -0.1 to 2 V, Vout = VCC/2
100
Tmin < Top < Tmax
94
Vicm = -0.1 to 4.1 V,
Vout = VCC/2
80
Tmin < Top < Tmax
78
Vicm = -0.1 to 2 V, Vout = VCC/2
91
Tmin < Top < Tmax
86
RL= 2 kΩ, Vout = 0.3 to 3.7 V
110
Tmin < Top < Tmax
96
RL= 10 kΩ, Vout = 0.2 to 3.8 V
110
Tmin < Top < Tmax
96
DocID025959 Rev 4
pA
1
TΩ
12.5
pF
102
122
98
dB
103
136
140
28
Tmin < Top < Tmax
Tmin < Top < Tmax
50
200
Vicm = -0.1 to 4.1 V,
Vout = VCC/2
RL= 10 kΩ tο VCC/2
50
200
Vout = VCC/2
RL= 2 kΩ to VCC/2
VOH
Max.
Vicm = VCC/2
Tmin < Top < Tmax
CMRR
(TSX711)
Avd
Typ.
(1)
Long term input offset
(2)
voltage drift
Input bias current
Min.
50
60
6
15
mV
20
5/30
Electrical characteristics
Symbol
TSX711, TSX712
Parameter
Conditions
Min.
RL= 2 kΩ tο VCC/2
VOL
Low level output voltage
Typ.
Max.
23
50
Tmin < Top < Tmax
60
RL= 10 kΩ tο VCC/2
5
Tmin < Top < Tmax
Isink
Iout
(TSX711)
Isource
Isink
Iout
(TSX712)
Isource
35
Tmin < Top < Tmax
20
Vout = 0 V
35
Tmin < Top < Tmax
20
Vout = VCC
25
Tmin < Top < Tmax
15
Vout = 0 V
35
Tmin < Top < Tmax
20
No load, Vout = VCC/2
Gain bandwidth product
RL = 10 kΩ, CL = 100 pF
ɸm
Phase margin
Gm
GBP
SRn
SRp
en
THD+N
mV
20
Vout = VCC
Supply current per
amplifier
ICC
15
Unit
45
45
mA
37
45
570
Tmin < Top < Tmax
800
μA
900
2.7
MHz
RL = 10 kΩ, CL = 100 pF
50
Degrees
Gain margin
RL = 10 kΩ, CL = 100 pF
15
dB
Negative slew rate
Av = 1, Vout = 3 VPP,
10 % to 90 %
0.6
Tmin < Top < Tmax
0.5
Av = 1, Vout = 3VPP,
10 % to 90 %
1.0
Tmin < Top < Tmax
0.9
Positive slew rate
1.9
0.85
V/μs
1.4
f = 1 kHz
22
Equivalent input noise
voltage
f = 10 kHz
19
Total harmonic distortion +
noise
f =1 kHz, Av = 1, RL= 10 kΩ,
BW = 22 kHz, Vin= 0.8 VPP
nV
-----------Hz
0.001
Notes:
(1)
Maximum values are guaranteed by design.
(2)
Typical value is based on the Vio drift observed after 1000h at 125 °C extrapolated to 25 °C using the Arrhenius law and
assuming an activation energy of 0.7 eV. The operational amplifier is aged in follower mode configuration (see Section 5.6).
6/30
DocID025959 Rev 4
%
TSX711, TSX712
Electrical characteristics
Table 4: Electrical characteristics at VCC+ = 10 V with VCC- = 0 V, Vicm = VCC/2,
Tamb = 25 °C, and RL > 10 kΩ connected to VCC/2 (unless otherwise specified)
Symbol
Parameter
Conditions
Vio
(TSX711,
TSX712)
Input offset voltage
Vio
(TSX711A)
ΔVio/ΔT
ΔVio
Iib
Input offset voltage drift
(1)
Iio
Input offset current
RIN
Input resistance
CIN
Input capacitance
(1)
Common mode rejection
ratio 20 log (ΔVic/ΔVio)
CMRR
(TSX712)
Large signal voltage gain
200
Tmin < Top < 85 °C
365
Tmin < Top < 125 °C
450
Vicm = VCC/2
100
Tmin < Top < 85 °C
265
Tmin < Top < 125 °C
350
2.5
T = 25 °C
25
Vout = VCC/2
1
High level output voltage
(voltage drop from VCC+)
1
Tmin < Top < Tmax
90
Tmin < Top < Tmax
86
Vicm = -0.1 to 8 V, Vout = VCC/2
105
Tmin < Top < Tmax
95
Vicm = -0.1 to 10.1 V,
Vout = VCC/2
88
Tmin < Top < Tmax
84
Vicm = -0.1 to 8 V, Vout = VCC/2
98
Tmin < Top < Tmax
92
RL= 2 kΩ, Vout = 0.3 to 9.7 V
110
Tmin < Top < Tmax
100
RL= 10 kΩ, Vout = 0.2 to 9.8 V
110
Tmin < Top < Tmax
100
Low level output voltage
Tmin < Top < Tmax
DocID025959 Rev 4
50
50
pA
12.5
pF
102
117
100
dB
106
140
45
70
80
10
30
40
42
Tmin < Top < Tmax
RL= 10 kΩ ο VCC/2
nV
month
TΩ
Tmin < Top < Tmax
VOL
μV/°C
1
Tmin < Top < Tmax
RL= 2 kΩ ο VCC/2
μV
200
Vicm = -0.1 to 10.1 V,
Vout = VCC/2
RL= 10 kΩ ο VCC/2
Unit
---------------------------
200
Vout = VCC/2
RL= 2 kΩ ο VCC/2
VOH
Max.
Vicm = VCC/2
Tmin < Top < Tmax
CMRR
(TSX711)
Avd
Typ.
(1)
Long term input offset
(2)
voltage drift
Input bias current
Min.
70
mV
80
9
30
40
7/30
Electrical characteristics
Symbol
TSX711, TSX712
Parameter
Isink
Iout
(TSX711)
Isource
Isink
Iout
(TSX712)
Isource
Conditions
Min.
Typ.
Vout = VCC
50
70
Tmin < Top < Tmax
40
Vout = 0 V
50
Tmin < Top < Tmax
40
Vout = VCC
30
Tmin < Top < Tmax
15
Vout = 0 V
50
Tmin < Top < Tmax
40
Supply current per
amplifier
No load, Vout = VCC/2
Gain bandwidth product
RL = 10 kΩ, CL = 100 pF
ɸm
Phase margin
Gm
ICC
GBP
SRn
SRp
en
THD+N
Max.
Unit
69
mA
39
69
630
Tmin < Top < Tmax
850
μA
1000
2.7
MHz
RL = 10 kΩ, CL = 100 pF
53
Degrees
Gain margin
RL = 10 kΩ, CL = 100 pF
15
dB
Negative slew rate
Av = 1, Vout = 8 VPP,
10 % to 90 %
0.8
Tmin < Top < Tmax
0.7
Av = 1, Vout = 8 VPP,
10 % to 90 %
1.0
Tmin < Top < Tmax
0.9
Positive slew rate
1.9
1
V/μs
1.3
f = 1 kHz
22
Equivalent input noise
voltage
f = 10 kHz
19
Total harmonic distortion +
noise
f = 1 kHz, Av = 1, RL= 10 kΩ,
BW = 22 kHz, Vin= 5 VPP
nV
-----------Hz
0.0003
Notes:
(1)
Maximum values are guaranteed by design.
(2)
Typical value is based on the Vio drift observed after 1000h at 125 °C extrapolated to 25 °C using the Arrhenius law and
assuming an activation energy of 0.7 eV. The operational amplifier is aged in follower mode configuration (see Section 5.6).
8/30
DocID025959 Rev 4
%
TSX711, TSX712
Electrical characteristics
Table 5: Electrical characteristics at VCC+ = 16 V with VCC- = 0 V, Vicm = VCC/2,
Tamb = 25 °C, and RL > 10 kΩ connected to VCC/2 (unless otherwise specified)
Symbol
Parameter
Conditions
Vio
(TSX711,
TSX712)
Input offset voltage
Vio
(TSX711A)
ΔVio/ΔT
ΔVio
Input offset voltage drift
(1)
Input bias current
Iio
Input offset current
RIN
Input resistance
CIN
Input capacitance
(1)
Common mode rejection
ratio 20 log (ΔVic/ΔVio)
CMRR
(TSX712)
Avd
Supply voltage rejection
ratio 20 log (ΔVcc/ΔVio)
Large signal voltage gain
Max.
Vicm = VCC/2
200
Tmin < Top < 85 °C
365
Tmin < Top < 125 °C
450
Vicm = VCC/2
100
Tmin < Top < 85 °C
265
Tmin < Top < 125 °C
350
2.5
T = 25 °C
Vout = VCC/2
1
1
Tmin < Top < Tmax
μV/°C
50
50
pA
200
Vicm = -0.1 to 16.1 V,
Vout = VCC/2
94
Tmin < Top < Tmax
90
Vicm = -0.1 to 14 V,
Vout = VCC/2
110
Tmin < Top < Tmax
96
Vicm = -0.1 to 16.1 V,
Vout = VCC/2
94
Tmin < Top < Tmax
90
Vicm = -0.1 to 14 V,
Vout = VCC/2
100
Tmin < Top < Tmax
90
Vcc = 4 to 16 V
100
Tmin < Top < Tmax
90
RL= 2 kΩ, Vout = 0.3 to 15.7 V
110
Tmin < Top < Tmax
100
RL= 10 kΩ, Vout = 0.2 to 15.8 V
110
Tmin < Top < Tmax
100
DocID025959 Rev 4
μV
nV
month
200
Vout = VCC/2
Unit
---------------------------
500
Tmin < Top < Tmax
CMRR
(TSX711)
SVRR
Typ.
(1)
Long term input offset
(2)
voltage drift
Iib
Min.
1
TΩ
12.5
pF
113
116
107
dB
107
131
146
149
9/30
Electrical characteristics
Symbol
VOH
TSX711, TSX712
Parameter
High level output voltage
(voltage drop from VCC+)
Conditions
Min.
Typ.
Max.
RL= 2 kΩ (TSX711)
100
130
RL= 2 kΩ (TSX712)
70
130
Tmin < Top < Tmax
150
RL= 10 kΩ
16
40
70
130
Tmin < Top < Tmax
Low level output voltage
Tmin < Top < Tmax
150
RL= 10 kΩ
15
Tmin < Top < Tmax
Isink
Iout
(TSX711)
Isource
Isink
Iout
(TSX712)
Isource
Vout = VCC
50
Tmin < Top < Tmax
45
Vout = 0 V
50
Tmin < Top < Tmax
45
Vout = VCC
30
Tmin < Top < Tmax
15
Vout = 0 V
50
Tmin < Top < Tmax
45
No load, Vout = VCC/2
Gain bandwidth product
RL = 10 kΩ, CL = 100 pF
ɸm
Phase margin
Gm
Gain margin
Negative slew rate
Av = 1, Vout = 10 VPP,
10 % to 90 %
0.7
Tmin < Top < Tmax
0.6
GBP
SRn
SRp
Positive slew rate
THD+N
mV
71
68
mA
40
68
660
Tmin < Top < Tmax
900
μA
1000
2.7
MHz
RL = 10 kΩ, CL = 100 pF
55
Degrees
RL = 10 kΩ, CL= 100 pF
15
dB
Av = 1, Vout = 10 VPP,
10 % to 90 %
Tmin < Top < Tmax
en
40
50
Supply current per
amplifier
ICC
mV
50
RL= 2 kΩ
VOL
Unit
1.9
1
0.95
V/μs
1.4
0.9
f = 1 kHz
22
Equivalent input noise
voltage
f = 10 kHz
19
Total harmonic distortion +
Noise
f = 1 kHz, Av = 1, RL= 10 kΩ,
BW = 22 kHz, Vin= 10 VPP
nV
-----------Hz
0.0002
Notes:
(1)
Maximum values are guaranteed by design.
(2)
Typical value is based on the Vio drift observed after 1000h at 125 °C extrapolated to 25 °C using the Arrhenius law and
assuming an activation energy of 0.7 eV. The operational amplifier is aged in follower mode configuration (see Section 5.6).
10/30
DocID025959 Rev 4
%
TSX711, TSX712
Electrical characteristic curves
Figure 2: Supply current vs. supply voltage
Figure 3: Input offset voltage distribution at VCC = 16 V
Figure 4: Input offset voltage distribution at VCC = 4 V
Figure 5: Input offset voltage vs. temperature at VCC = 16 V
600
Vio limit
400
Input offset voltage (µV)
4
Electrical characteristic curves
200
0
-200
-400
-600
-40
Figure 6: Input offset voltage drift population
Vcc=16V
Vicm=8V
-20
0
20
40
60
Temperature (°C)
80
100
120
Figure 7: Input offset voltage vs. supply voltage at VICM = 0 V
DocID025959 Rev 4
11/30
Electrical characteristic curves
TSX711, TSX712
Figure 8: Input offset voltage vs. common mode voltage
at VCC = 2.7 V
Figure 9: Input offset voltage vs. common mode voltage
at VCC = 16 V
Figure 10: Output current vs. output voltage
at VCC = 2.7 V (TSX711)
Figure 11: Output current vs. output voltage
at VCC = 16 V (TSX711)
Figure 12: Output current vs. output voltage
at VCC = 2.7 V (TSX712)
Figure 13: Output current vs. output voltage
at VCC = 16 V (TSX712)
12/30
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TSX711, TSX712
Electrical characteristic curves
Figure 14: Output low voltage vs. supply voltage
Figure 15: Output high voltage (drop from VCC+) vs.
supply voltage
Figure 16: Output voltage vs. input voltage close to the rail
at VCC = 16 V
Figure 17: Slew rate vs. supply voltage
Figure 18: Negative slew rate at VCC = 16 V
Figure 19: Positive slew rate at VCC = 16 V
DocID025959 Rev 4
13/30
Electrical characteristic curves
TSX711, TSX712
Figure 20: Response to a small input voltage step
Figure 21: Recovery behavior after a negative step on the input
Figure 22: Recovery behavior after a positive step on the input
Figure 23: Bode diagram at VCC = 2.7 V
Figure 24: Bode diagram at VCC = 16 V
Figure 25: Power supply rejection ratio (PSRR) vs. frequency
14/30
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TSX711, TSX712
Electrical characteristic curves
Figure 26: Output overshoot vs. capacitive load
Figure 27: Output impedance vs. frequency in closed loop
configuration
Figure 28: THD + N vs. frequency
Figure 29: THD + N vs. output voltage
Figure 30: Noise vs. frequency
Figure 31: 0.1 to 10Hz noise
DocID025959 Rev 4
15/30
Electrical characteristic curves
TSX711, TSX712
Figure 32: Channel separation (TSX712)
16/30
DocID025959 Rev 4
TSX711, TSX712
Application information
5
Application information
5.1
Operating voltages
The TSX711 and TSX712 devices can operate from 2.7 to 16 V. The parameters are fully
specified for 4 V, 10 V, and 16 V power supplies. However, the parameters are very stable
in the full VCC range. Additionally, the main specifications are guaranteed in extended
temperature ranges from -40 to 125 °C.
5.2
Input pin voltage ranges
The TSX711 and TSX712 devices have internal ESD diode protection on the inputs. These
diodes are connected between the input and each supply rail to protect the input MOSFETs
from electrical discharge.
If the input pin voltage exceeds the power supply by 0.5 V, the ESD diodes become
conductive and excessive current can flow through them. Without limitation this over
current can damage the device.
In this case, it is important to limit the current to 10 mA, by adding resistance on the input
pin, as described in Figure 33: "Input current limitation".
Figure 33: Input current limitation
16 V
R
Vin
5.3
-
+
+
-
Vout
Rail-to-rail input
The TSX711 and TSX712 devices have a rail-to-rail input, and the input common mode
range is extended from (VCC-) - 0.1 V to (VCC+) + 0.1 V.
5.4
Rail-to-rail output
The operational amplifier output levels can go close to the rails: to a maximum of 40 mV
above and below the rail when connected to a 10 kΩ resistive load to V CC/2.
DocID025959 Rev 4
17/30
Application information
5.5
TSX711, TSX712
Input offset voltage drift over temperature
The maximum input voltage drift variation over temperature is defined as the offset
variation related to the offset value measured at 25 °C. The operational amplifier is one of
the main circuits of the signal conditioning chain, and the amplifier input offset is a major
contributor to the chain accuracy. The signal chain accuracy at 25 °C can be compensated
during production at application level. The maximum input voltage drift over temperature
enables the system designer to anticipate the effect of temperature variations.
The maximum input voltage drift over temperature is computed using Equation 1.
Equation 1
∆Vio
V T – Vio 25 °C
= max io
∆T
T – 25 °C
Where T = -40 °C and 125 °C.
The TSX711 and TSX712 datasheet maximum values are guaranteed by measurements
on a representative sample size ensuring a Cpk (process capability index) greater than 1.3.
5.6
Long term input offset voltage drift
To evaluate product reliability, two types of stress acceleration are used:
Voltage acceleration, by changing the applied voltage
Temperature acceleration, by changing the die temperature (below the maximum
junction temperature allowed by the technology) with the ambient temperature.
The voltage acceleration has been defined based on JEDEC results, and is defined using
Equation 2.
Equation 2
AFV = e
β . V S – VU
Where:
AFV is the voltage acceleration factor
β is the voltage acceleration constant in 1/V, constant technology parameter (β = 1)
VS is the stress voltage used for the accelerated test
VU is the voltage used for the application
The temperature acceleration is driven by the Arrhenius model, and is defined in
Equation 3.
Equation 3
AFT = e
Ea
1
1
------ .
–
k
TU TS
Where:
AFT is the temperature acceleration factor
Ea is the activation energy of the technology based on the failure rate
18/30
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TSX711, TSX712
Application information
-5
-1
k is the Boltzmann constant (8.6173 x 10 eV.K )
TU is the temperature of the die when VU is used (K)
TS is the temperature of the die under temperature stress (K)
The final acceleration factor, AF, is the multiplication of the voltage acceleration factor and
the temperature acceleration factor (Equation 4).
Equation 4
AF = AFT × AFV
AF is calculated using the temperature and voltage defined in the mission profile of the
product. The AF value can then be used in Equation 5 to calculate the number of months of
use equivalent to 1000 hours of reliable stress duration.
Equation 5
Months = AF × 1000 h × 12 months / 24 h × 365.25 days
To evaluate the op amp reliability, a follower stress condition is used where V CC is defined
as a function of the maximum operating voltage and the absolute maximum rating
(as recommended by JEDEC rules).
The Vio drift (in µV) of the product after 1000 h of stress is tracked with parameters at
different measurement conditions (see Equation 6).
Equation 6
VCC = maxVop with Vicm = VCC 2
The long term drift parameter (ΔVio), estimating the reliability performance of the product, is
obtained using the ratio of the Vio (input offset voltage value) drift over the square root of
the calculated number of months (Equation 7).
Equation 7
∆Vio =
Vio dr ift
month s
Where Vio drift is the measured drift value in the specified test conditions after 1000 h
stress duration.
5.7
High values of input differential voltage
In a closed loop configuration, which represents the typical use of an op amp, the input
differential voltage is low (close to Vio). However, some specific conditions can lead to
higher input differential values, such as:
operation in an output saturation state
operation at speeds higher than the device bandwidth, with output voltage dynamics
limited by slew rate.
use of the amplifier in a comparator configuration, hence in open loop
Use of the TSX711 or TSX712 in comparator configuration, especially combined with high
temperature and long duration can create a permanent drift of Vio.
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Application information
5.8
TSX711, TSX712
Capacitive load
Driving large capacitive loads can cause stability problems. Increasing the load
capacitance produces gain peaking in the frequency response, with overshoot and ringing
in the step response. It is usually considered that with a gain peaking higher than 2.3 dB an
op amp might become unstable.
Generally, the unity gain configuration is the worst case for stability and the ability to drive
large capacitive loads.
Figure 34: "Stability criteria with a serial resistor at different supply voltage" shows the
serial resistor that must be added to the output, to make a system stable. Figure 35: "Test
configuration for Riso" shows the test configuration using an isolation resistor, Riso.
Figure 34: Stability criteria with a serial resistor at different supply voltage
1000
Vcc=16V
Riso (Ω)
Stable
Vcc=2.7V
100
Unstable
Vicm=Vcc/2
Rl=10kΩ
Gain=1
T=25°C
10
100 p
1n
10 n
100 n
Cload (F)
Figure 35: Test configuration for Riso
V CC+
Riso
VIN
+
Cload
V CC-
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VOUT
10 kΩ
TSX711, TSX712
5.9
Application information
PCB layout recommendations
Particular attention must be paid to the layout of the PCB, tracks connected to the amplifier,
load, and power supply. The power and ground traces are critical as they must provide
adequate energy and grounding for all circuits. The best practice is to use short and wide
PCB traces to minimize voltage drops and parasitic inductance.
In addition, to minimize parasitic impedance over the entire surface, a multi-via technique
that connects the bottom and top layer ground planes together in many locations is often
used.
The copper traces that connect the output pins to the load and supply pins should be as
wide as possible to minimize trace resistance.
5.10
Optimized application recommendation
It is recommended to place a 22 nF capacitor as close as possible to the supply pin. A
good decoupling will help to reduce electromagnetic interference impact.
5.11
Application examples
5.11.1
Oxygen sensor
The electrochemical sensor creates a current proportional to the concentration of the gas
being measured. This current is converted into voltage thanks to R resistance. This voltage
is then amplified by the TSX711 or the TSX712 (see Figure 36: "Oxygen sensor principle
schematic").
Figure 36: Oxygen sensor principle schematic
R1
R2
VCC
I
O2_ sensor
+
+
Vout
-
The output voltage is calculated using Equation 8:
Equation 8
Vou t = I × R – Vio ×
R2
+1
R1
As the current delivered by the O2 sensor is extremely low, the impact of the V io can
become significant with a traditional operational amplifier. The use of a precision amplifier
like the TSX711/TSX712 is perfect for this application.
In addition, using the TSX711/TSX712 for the O2 sensor application ensures that the
measurement of O2 concentration is stable, even at different temperatures, thanks to a
small ΔVio/ΔT.
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Application information
5.11.2
TSX711, TSX712
Low-side current sensing
Power management mechanisms are found in most electronic systems. Current sensing is
useful for protecting applications. The low-side current sensing method consists of placing
a sense resistor between the load and the circuit ground. The resulting voltage drop is
amplified using the TSX711 or TSX712 (see Figure 37: "Low-side current sensing
schematic").
Figure 37: Low-side current sensing schematic
C1
Rg1
I
Rf1
In
Rshunt
Rg2
Ip
5V
- +
+ -
Vout
Rf2
Vout can be expressed as follows:
Equation 9
Vou t = Rshun t × I 1 –
Rg2
Rg2 + Rf2
1+
Rg2 × Rf2
Rf1
Rf1
Rf1
+ Ip
– l n × Rf1 – Vio 1 +
× 1+
Rg2 + Rf2
Rg1
Rg1
Rg1
Assuming that Rf2 = Rf1 = Rf and Rg2 = Rg1 = Rg, Equation 9 can be simplified as follows:
Equation 10
Vout = Rshunt × I
Rf
Rf
– Vio 1 +
+ Rf × I io
Rg
Rg
The main advantage of using a precision amplifier like the TSX711 or TSX712, for a
low-side current sensing, is that the errors due to Vio and Iio are extremely low and may be
neglected.
Therefore, for the same accuracy, the shunt resistor can be chosen with a lower value,
resulting in lower power dissipation, lower drop in the ground path, and lower cost.
Particular attention must be paid on the matching and precision of Rg1, Rg2, Rf1, and Rf2, to
maximize the accuracy of the measurement.
Taking into consideration the resistor inaccuracies, the maximum and minimum output
voltage of the operational amplifier can be calculated respectively using Equation 11 and
Equation 12.
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TSX711, TSX712
Application information
Equation 11
Maximum Vout = Rshunt × I ×
Rf
Rf
× 1 + ε rs + 2ε r + Vi o × 1 +
+ Rf × li o
Rg
Rg
Equation 12
Minimum Vout = Rshunt × I ×
Rf
Rf
× 1 – ε rs – 2ε r – Vi o × 1 +
+ Rf × lio
Rg
Rg
Where:
εrs is the shunt resistor inaccuracy (example, 1 % )
εr is the inaccuracy of the Rf and Rg resistors (example, 0.1 %)
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Package information
6
TSX711, TSX712
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.
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TSX711, TSX712
6.1
Package information
SOT23-5 package information
Figure 38: SOT23-5 package outline
Table 6: SOT23-5 mechanical data
Dimensions
Ref.
A
Millimeters
Inches
Min.
Typ.
Max.
Min.
Typ.
Max.
0.90
1.20
1.45
0.035
0.047
0.057
A1
0.15
0.006
A2
0.90
1.05
1.30
0.035
0.041
0.051
B
0.35
0.40
0.50
0.014
0.016
0.020
C
0.09
0.15
0.20
0.004
0.006
0.008
D
2.80
2.90
3.00
0.110
0.114
0.118
D1
1.90
0.075
e
0.95
0.037
E
2.60
2.80
3.00
0.102
0.110
0.118
F
1.50
1.60
1.75
0.059
0.063
0.069
L
0.10
0.35
0.60
0.004
0.014
0.024
K
0 degrees
10 degrees
0 degrees
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10 degrees
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Package information
6.2
TSX711, TSX712
MiniSO8 package information
Figure 39: MiniSO8 package outline
Table 7: MiniSO8 mechanical data
Dimensions
Ref.
Millimeters
Min.
Typ.
A
0
Min.
Typ.
A2
0.75
b
0.22
c
0.08
D
2.80
E
E1
0.043
0
0.95
0.030
0.40
0.009
0.016
0.23
0.003
0.009
3.00
3.20
0.11
0.118
0.126
4.65
4.90
5.15
0.183
0.193
0.203
2.80
3.00
3.10
0.11
0.118
0.122
0.85
0.65
0.40
0.60
0.006
0.033
0.80
0.016
0.024
0.95
0.037
L2
0.25
0.010
ccc
0°
0.037
0.026
L1
k
Max.
0.15
e
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Max.
1.1
A1
L
Inches
8°
0.10
DocID025959 Rev 4
0°
0.031
8°
0.004
TSX711, TSX712
6.3
Package information
SO8 package information
Figure 40: SO8 package outline
Table 8: SO8 mechanical data
Dimensions
Ref.
Millimeters
Min.
Typ.
A
Inches
Max.
Min.
Typ.
1.75
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
0.25
Max
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
1.04
1°
0.040
8°
0.10
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8°
0.004
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Ordering information
7
TSX711, TSX712
Ordering information
Table 9: Order codes
Order code
Temperature range
TSX711ILT
Packaging
(1)
(1)
TSX711AIYLT
TSX712IDT
TSX712IST
TSX712IYDT
(2)
TSX712IYST
(2)
K195
SΟΤ23-5
K197
-40 to 125 °C
(automotive grade)
-40 to 125 °C
-40 to 125 °C
(automotive grade)
Marking
K29
-40 to 125 °C
TSX711AILT
TSX711IYLT
Package
SO8
Tape and reel
K198
TSX712
MiniSO8
K211
SO8
TSX712Y
MiniSO8
K212
Notes:
(1)
Qualification and characterization according to AEC Q100 and Q003 or equivalent, advanced screening
according to AEC Q001 & Q 002 or equivalent are on-going.
(2)
Qualification and characterization according to AEC Q100 and Q003 or equivalent, advanced screening
according to AEC Q001 & Q 002 or equivalent.
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TSX711, TSX712
8
Revision history
Revision history
Table 10: Document revision history
Date
Revision
27-Feb-2014
1
Initial release
19-Mar-2014
2
Table 1: updated ESD data for MM (machine model)
3
Table 3: updated Iout (Isink) values.
Table 3, Table 4, and Table 5: updated Vio values,
updated ΔVio/ΔT.
Table 5: updated VOL values
Table 6: updated “inches” dimensions
4
TSX711 datasheet merged with TSX712 datasheet.
Reworked the following sections: Cover image,
Related products, Description, Section 1: "Package pin
connections", Section 2: "Absolute maximum ratings
and operating conditions", Section 3: "Electrical
characteristics", Section 4: "Electrical characteristic
curves", Section 5.1: "Operating voltages", Section
5.2: "Input pin voltage ranges", Section 5.3: "Rail-torail input", Section 5.4: "Rail-to-rail output", Section
5.5: "Input offset voltage drift over temperature",
Section 5.7: "High values of input differential voltage",
Section 5.11.1: "Oxygen sensor", Section 5.11.2:
"Low-side current sensing", Section 7: "Ordering
information".
Added: Section 6.2: "MiniSO8 package information"
and Section 6.3: "SO8 package information"
25-Jul-2014
26-Jan-2016
Changes
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TSX711, TSX712
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