LF355AH National Semiconductor, LF355AH Datasheet - Page 14

• Manufacturer Part Number: LF355AH
• Description: Series Monolithic JFET Input Operational Amplifiers
• Manufacturer: National Semiconductor

Typical Applications
Both amplifiers (A1 A2) have feedback loops individually closed with stable responses (overshoot negligible)
Acquisition time T
T
V
If inequality not satisfied T
LF156 develops full S
Addition of SW2 improves accuracy by putting the voltage drop across SW1 inside the feedback loop
Overall accuracy of system determined by the accuracy of both amplifiers A1 and A2
A
IN k
j
By closing the loop through A2 the V
No V
T
propagation delay in the feedback loop (A2) the overshoot is not negligible
Overall system slower than fast sample and hold
R1 C
Use LF156 for
X
X
A
Fast settling time
Low V
2 S
can be estimated by same considerations as previously but because of the added
2R
OS
C
ON
r
R
additional compensation
OS
adjust required for A2
S
ON
V
r
IN
C
(Continued)
A
h
C
estimated by
and T
h
r
output capability for V
A l
A
provided that
j
I
OUT(MAX)
V
20 mA
High Accuracy Sample and Hold
V
IN
IN
C
C
h
h
Fast Sample and Hold
R
OUT
ON
IN t
is of SW1
accuracy will be determined uniquely by A1
1V
14
TL H 5646– 27
TL H 5646 – 33