Datasheet

APPLICATIONS INFORMATION
POWER SUPPLIES
INPUT PROTECTION
R
L
R
2
R
1
OPA454
V-
V+
V+
V
IN
G=1+
R
2
R
1
0.1 Fm
0.1 Fm
V
OUT
Status
Flag
E/DCom
R
(1)
P
I
P
V
OUT
E/D
V+
V-
V-
-IN
+IN
LOWERING OFFSET VOLTAGE AND DRIFT
R ,1st
2
39.1kW
R ,1st
1
10kW
OPA735
V+
1stStage,+5V
V-
1stStage, 5V-
R ,2nd
2
84.5kW
R ,2nd
1
10kW
OPA454
V+
2ndStage,+50V
V-
2ndStage, 50V-
A ,1stStage
1
A ,2ndStage
2
V 2ndStage
OUT
V 1stStage
OUT
R
LOAD
10kW
LowOffset,5 V,Drift,m
0.05 V/ C,Self-ZeroingOpAmpm °
Gain1st=4.9V/V
High-VoltageOpAmp
Gain2nd=9.45V/V
V = 1V±
INPUT PP
V 1stStage 4.9V,Max
OUT
±
V 2ndStage 46V(92V ),Max
OUT PP
±
V = 1V
G
±
OPA454
SBOS391A – DECEMBER 2007 – REVISED DECEMBER 2008 ....................................................................................................................................... www.ti.com
Figure 57 shows the OPA454 connected as a basic
noninverting amplifier. The OPA454 can be used in The OPA454 may be operated from power supplies
virtually any ± 5V to ± 50V op amp configuration. It is up to ± 50V or a total of 100V with excellent
especially useful for supply voltages greater than performance. Most behavior remains unchanged
36V. throughout the full operating voltage range.
Parameters that vary significantly with operating
Power-supply terminals should be bypassed with
voltage are shown in the Typical Characteristics .
0.1 µ F (or greater) capacitors, located near the
power-supply pins. Be sure that the capacitors are Some applications do not require equal positive and
appropriately rated for the power-supply voltage negative output voltage swing. Power-supply voltages
used. do not need to be equal. The OPA454 can operate
with as little as 10V between the supplies and with up
to 100V between the supplies. For example, the
positive supply could be set to 90V with the negative
supply at – 10V, or vice-versa (as long as the total is
less than or equal to 100V).
The OPA454 has increased protection against
damage caused by excessive voltage between op
amp input pins or input pin voltages that exceed the
power supplies; external series resistance is not
needed for protection. Internal series JFETs limit
input overload current to a non-destructive 4mA, even
with an input differential voltage as large as 120V.
Additionally, the OPA454 has dielectric isolation
between devices and the substrate. Therefore, the
amplifier is free from the limitations of junction
(1) Pull-up resistor with at least 10 µ A (choose
isolation common to many IC fabrication processes.
R
P
= 1M Ω with V+ = 50V for I
P
= 50 µ A).
Figure 57. Basic Noninverting Amplifier
Configuration
The OPA454 can be used with an OPA735 zero-drift
series op amp to create a high-voltage op amp circuit
that has very low input offset temperature drift. This
circuit is shown in Figure 58 .
Figure 58. Two-Stage, High-Voltage Op Amp Circuit With Very Low Input Offset Temperature Drift
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