5

Saturation Recovery

When an op amp is over driven, output devices can saturate

and sometimes take a long time to recover. By clamping the

input, output saturation can be avoided. If output saturation

can not be avoided, the maximum recovery time when

overdriven into the positive rail is 10.6

µs. When driven into

the negative rail the maximum recovery time is 3.8

µs.

Input Protection

The HA-5221 has built in back-to-back protection diodes

which limit the maximum allowable differential input voltage

to approximately 5V. If the HA-5221 is used in circuits where

the maximum differential voltage may be exceeded, then

current limiting resistors must be used. The input current

should be limited to a maximum of 10mA.

PC Board Layout Guidelines

When designing with the HA-5221, good high frequency

(RF) techniques should be used when building a PC board.

Use of ground plane is recommended. Power supply

decoupling is very important. A 0.01

µF to 0.1µF high quality

ceramic capacitor at each power supply pin with a 2.2

µF to

10

µF tantalum close by will provide excellent decoupling.

Chip capacitors produce the best results due to ease of

placement next to the op amp and basically no lead

inductance. If leaded capacitors are used, the leads should

be kept as short as possible to minimize lead inductance.

+

2

3

6

FIGURE 5. OPEN LOOP GAIN AND PHASE vs FREQUENCY

FIGURE 6. CLOSED LOOP GAIN vs FREQUENCY

FIGURE 7. CLOSED LOOP GAIN vs FREQUENCY

FIGURE 8. VARIOUS CLOSED LOOP GAINS vs FREQUENCY

GAIN

PHASE

FREQUENCY (Hz)

120

100

80

60

40

20

0

1K

10K

100K

1M

100M

0

45

90

135

180

10M

GAIN

PHASE

FREQUENCY (Hz)

10K

100K

1M

100M

0

45

90

135

180

10M

12

9

6

3

0

-3

-6

GAIN

PHASE

FREQUENCY (Hz)

10K

100K

1M

100M

0

45

90

135

180

10M

9

6

3

0

FREQUENCY (Hz)

10K

100K

1M

100M

0

45

90

135

180

10M

80

60

40

20

0

HA-5221