–8–

OP400

REV. A

Figure 3. Burn-In Circuit

APPLICATIONS INFORMATION

The OP400 is inherently stable at all gains and is capable of

driving large capacitive loads without oscillating. Nonetheless,

good supply decoupling is highly recommended. Proper supply

decoupling reduces problems caused by supply line noise and

improves the capacitive load driving capability of the OP400.

Total supply current can be reduced by connecting the inputs of

an unused amplifier to –V. This turns the amplifier off, lowering

the total supply current.

APPLICATIONS

Dual Low-Power Instrumentation Amplifier

A dual instrumentation amplifier that consumes less than 33 mW

of power per channel is shown in Figure 1. The linearity of the

instrumentation amplifier exceeds 16 bits in gains of 5 to 200

and is better than 14 bits in gains from 200 to 1000. CMRR is

above 115 dB (G = 1000). Offset voltage drift is typically 0.4

mV/∞C over the military temperature range which is comparable

to the best monolithic instrumentation amplifiers. The band-

width of the low-power instrumentation amplifier is a function

of gain and is shown in Table I.

Table I. Gain Bandwidth

Gain

Bandwidth

5

150 kHz

10

67 kHz

100

7.5 kHz

1000

500 Hz

The output signal is specified with respect to the reference

input, which is normally connected to analog ground. The refer-

ence input can be used to offset the output from –10 V to +10 V

if required.

Figure 4. Dual Low-Power Instrumentation Amplifier