REV. E

–6–

OP297

FREQUENCY (Hz)

–40

100

1k

10M

10k

100

1M

GAIN

PHASE

–20

0

20

40

60

100

80

TPC 19. Open Loop Gain, Phase

vs. Frequency

LOAD CAPACITANCE (pF)

0

0

100

–EDGE

10

20

30

40

50

60

70

1000

10000

+EDGE

TPC 20. Small-Signal Over-

shoot vs. Load Capacitance

FREQUENCY (Hz)

1000

0.001

10

100

1k

100

10

0.01

0.1

1

10k

100k

1M

TPC 21. Open Loop Output

Impedance vs Frequency

APPLICATIONS INFORMATION

Extremely low bias current over a wide temperature range makes

the OP297 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 unnecessary

minimally by high source resistance, even when unbalanced.

The input pins of the OP297 are protected against large differ-

ential 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 OP297 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. The output typically swings to within 1 V of the

rails when using a 10 k

Ω load.

AC PERFORMANCE

The OP297’s ac characteristics are highly stable over its full

operating temperature range. Unity gain small-signal response is

shown in Figure 4. Extremely tolerant of capacitive loading on

the output, the OP297 displays excellent response with 1000 pF

loads (Figure 5).

10

0%

100

90

5 s

20mV

Figure 4. Small-Signal Transient Response

10

0%

100

90

5 s

20mV

Figure 5. Small-Signal Transient Response

10

0%

100

90

5 s

20mV

Figure 6. Large-Signal Transient Response