
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
μ
s. When driven into
the negative rail the maximum recovery time is 3.8
μ
s.
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
μ
F to 0.1
μ
F high quality
ceramic capacitor at each power supply pin with a 2.2
μ
F to
10
μ
F 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.
+
R
LIMIT
R
LIMIT
V
OUT
2
3
6
V
IN
Typical Performance Curves
V
S
=
±
15V, T
A
= 25
o
C
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
G
FREQUENCY (Hz)
120
100
80
60
40
20
0
1K
10K
100K
1M
100M
0
45
90
135
180
P
R
L
= 1K, C
L
= 50pF
10M
GAIN
PHASE
FREQUENCY (Hz)
G
P
10K
100K
1M
100M
0
45
90
135
180
10M
12
9
6
3
0
-3
-6
A
V
= +1, R
L
= 1K, C
L
= 50pF
GAIN
PHASE
FREQUENCY (Hz)
G
P
10K
100K
1M
100M
0
45
90
135
180
9
6
3
0
A
V
= -1, R
L
= 1K, C
L
= 50pF
FREQUENCY (Hz)
P
10K
100K
1M
100M
0
45
90
135
180
10M
80
60
40
20
0
C
R
L
= 1K, C
L
= 50pF
A
V
= -1000
A
V
= -100
A
V
= -10
A
V
= -1000
A
V
= -100
A
V
= -10
HA-5221