Datasheet

-
F
G
R
G =
R
F
SIG REF
G
R
V = V + V
OUT
R
æ ö
-
ç ÷
è ø
OPA 835
V
SIG
V
REF
V
IN
V
REF
R
G
V
S+
V
S-
R
F
V
OUT
V
REF
GV
SIG
F
G
R
G = 1 +
R
æ ö
ç ÷
è ø
F
SIG REF
G
R
V = V 1 + + V
OUT
R
OPA835
OPA2835
www.ti.com SLOS713E –JANUARY 2011–REVISED JULY 2013
APPLICATION INFORMATION
The following circuits show application information for the OPA835 and OPA2835. For simplicity, power supply
decoupling capacitors are not shown in these diagrams.
Non-Inverting Amplifier
The OPA835 and OPA2835 can be used as non-inverting amplifiers with signal input to the non-inverting input,
V
IN+
. A basic block diagram of the circuit is shown in Figure 53.
If we set V
IN
= V
REF
+ V
SIG
, then
(1)
The signal gain of the circuit is set by: , and V
REF
provides a reference around which the input and
output signals swing. Output signals are in-phase with the input signals.
The OPA835 and OPA2835 are designed for the nominal value of R
F
to be 2kΩ in gains other than +1. This
gives excellent distortion performance, maximum bandwidth, best flatness, and best pulse response. R
F
= 2kΩ
should be used as a default unless other design goals require changing to other values All test circuits used to
collect data for this data sheet had R
F
= 2kΩ for all gains other than +1. Gain of +1 is a special case where R
F
is
shorted and R
G
is left open.
Figure 53. Non-Inverting Amplifier
Inverting Amplifier
The OPA835 and OPA2835 can be used as inverting amplifiers with signal input to the inverting input, V
IN-
,
through the gain setting resistor R
G
. A basic block diagram of the circuit is shown in Figure 54.
If we set V
IN
= V
REF
+ V
SIG
, then
(2)
The signal gain of the circuit is set by: and V
REF
provides a reference point around which the input
and output signals swing. Output signals are 180˚ out-of-phase with the input signals. The nominal value of R
F
should be 2kΩ for inverting gains.
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