OPA192-Q1 Datasheet, PDF (24/42 Pages) Texas Instruments – 36-V, Precision, Rail-to-Rail Input/Output, Low-Offset Voltage, Low-Input Bias Current Op Amp With e-trim

OPA192-Q1, OPA2192-Q1, OPA4192-Q1
SBOS850 – MAY 2017
www.ti.com
8.3 Feature Description
8.3.1 Input Protection Circuitry
The OPAx192-Q1 uses a unique input architecture to eliminate the need for input protection diodes but still
provides robust input protection under transient conditions. Conventional input diode protection schemes shown
in Figure 54 can be activated by fast transient step responses and can introduce signal distortion and settling
time delays because of alternate current paths, as shown in Figure 55. For low-gain circuits, these fast-ramping
input signals forward-bias back-to-back diodes, causing an increase in input current, and resulting in extended
settling time, as shown in Figure 56.
V+
V+
VIN+
VIN
36 V
OPAx192-Q1
VOUT
VIN+
VIN
~0.7 V
VOUT
OPA192-Q1 Provides Full
V
36-V Differential Input
Range
Conventional Input Protection
V
Limits Differential Input Range
Copyright © 2017, Texas Instruments Incorporated
Figure 54. OPAx192-Q1 Input Protection Does Not Limit Differential Input Capability
Vn = +10 V R_FILT
+10 V
C_FILT
Vn+1 = ±10 V R_FILT
±10 V
C_FILT
Input Low Pass Filter
S_n
C_S
R_{on_mux}
1
D
1
2
+10 V
~±9.3 V
C_D
S_n+1
R_{on_mux}
2
Vin±
C_S
I_{diode_transient}
~0.7 V
Vin+
±10 V
Vout
Simplified Mux Model
Buffer Amplifier
Figure 55. Back-to-Back Diodes Create Settling Issues
100
80
60
40
20
0
–20
–40
–60
–80
–100
0
Standard Input Diode Structure
Extends Settling Time
0.1% Settling = ±10 mV
OPA192-Q1 Input Structure
Offers Fast Settling
5 10 15 20 25 30 35 40 45 50 55 60
Time (µs)
C040
Figure 56. OPAx192-Q1 Protection Circuit Maintains Fast-Settling Transient Response
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Product Folder Links: OPA192-Q1 OPA2192-Q1 OPA4192-Q1