OP249

Rev. F | Page 17 of 20

As seen in Figure 51, the OP249 has an extremely fast recovery

of 247 ns (to 0.01%) for a 1 mA load transient. The performance

makes it an ideal amplifier for data acquisition systems.

The combination of high speed and excellent dc performance of

the OP249 makes it an ideal amplifier for 12-bit data acquisition

systems. Examining the circuit in Figure 53, one amplifier in the

the ADC912. The other amplifier in the OP249 performs high

speed buffering of the input of the ADC.

node of the ADC, it is shown that the OP249 recovers in less

than 100 ns (see Figure 52). The fast recovery is due to both the

wide bandwidth and low dc output impedance of the OP249.

10

0%

100

90

100ns

2V

2mV

247.4ns

Figure 51. Transient Recovery Time of the OP249 from

a 1 mA Load Transient to 0.01%

10

0%

100

90

100ns

5mV

Figure 52. Worst-Case Transient Voltage at Analog In Occurs at

the Half-Scale Point of the ADC; the OP249 Buffers the

ADC Input from Figure 53 and Recovers in <100 ns

+15V

AGND

DGND HBEN

BUSY

CLK IN

ADC912A

RD

+5V

+15V

10Ω

REF02

GND

CS

–15V

10µF||0.1µF

10µF||0.1µF

0.1µF

0.1µF

ANALOG

INPUT

1/2

OP249

–15V

–5V

10µF||0.1µF

0.1µF

0.1µF

1/2

OP249

3

2

8

4

1

24

23

20

17

22

21

19

12

3

2

1

2

6

5

6

1

4

Figure 53. OP249 Dual Amplifiers Provide Both Stable −5 V Reference Input and Buffers Input to ADC912A