OP497

Rev. E | Page 10 of 16

APPLICATIONS INFORMATION

Extremely low bias current makes the OP497 attractive for use

in sample-and-hold amplifiers, peak detectors, and log amplifiers

that must operate over a wide temperature range. Balancing

input resistances is not necessary with the OP497. High source

resistance, even when unbalanced, only minimally degrades the

The input pins of the OP497 are protected against large differential

voltage by back-to-back diodes and current-limiting resistors.

Common-mode voltages at the inputs are not restricted and

may vary over the full range of the supply voltages used.

The OP497 requires very little operating headroom about the

supply rails and is specified for operation with supplies as low as

±2 V. Typically, the common-mode range extends to within 1 V

of either rail. When using a 10 kΩ load, the output typically

swings to within 1 V of the rails.

AC PERFORMANCE

The ac characteristics of the OP497 are highly stable over its full

operating temperature range. Figure 30 shows the unity-gain

small signal response. Extremely tolerant of capacitive loading

on the output, the OP497 displays excellent response even with

1000 pF loads (see Figure 31).

10

90

100

0%

20mV

5µs

10

90

100

0%

20mV

5µs

10

90

100

0%

2V

50µs

–IN

+IN

2.5k

Ω

V+

V–

2.5k

Ω

Figure 33. Simplified Schematic Showing One Amplifier