LT1056 LINER [Linear Technology], LT1056 Datasheet - Page 9

• Manufacturer Part Number: LT1056
• Description: Precision, High Speed, JFET Input Operational Amplifiers
• Manufacturer: LINER [Linear Technology]

APPLICATIONS
Phase Reversal Protection
Most industry standard JFET input op amps (e.g., LF155/
LF156, LF351, LF411, OP15/16) exhibit phase reversal at
the output when the negitive common-mode limit at the
input is exceeded (i.e., from –12V to –15V with 15V
supplies). This can cause lock-up in servo systems. As
shown below, the LT1055/LT1056 does not have this
problem due to unique phase reversal protection circuitry
(Q1 on simplified schematic).
TYPICAL APPLICATIONS
SCALE FACTOR
1V IN OCTAVE OUT
*1% METAL FILM RESISTOR
PIN NUMBERED TRANSISTORS = CA3096 ARRAY
15V
EXPONENT
0.5ms/DIV
2500 *
ZERO TRIM
562 *
TRIM
Input
U
3.57k*
0V TO 10V
INPUT
INFORMATION
U
11.3k*
Exponential Voltage-to-Frequency Converter for Music Synthesizers
LT1055/56 AI06
10k*
1k*
4.7k
U
500k
W
2
6
1
†
5
4
3
1.1k
10k*
2
3
2
3
TEMPERATURE CONTROL LOOP
(LF155/LF56, LF441, OP-15/OP-16)
U
–15V
+
–
+
–
POLYSTYRENE
LM301A
LT1055
4
–15V
1
15V
15V
0.01µF
500pF
7
7
8
6
0.5ms/DIV
6
Output
1N148
3k
LM329
2N3906
Voltage Follower with Input Exceeding the Negative
Common-Mode Range
2N3904
500 *
15 2.2k
13
LT1055/56 AI07
14
SINE WAVE
INPUT
±15V
1k*
4.7k
8
SAWTOOTH
OUTPUT
15V
9
7
LT1055/56 TA03
33
3
2
–
+
LT1055/56
–15V
15V
7
4
LT1055/LT1056
†
LT1055 and LT1056, please see the LTC1043
data sheet and Application Note 3.
For ten additional applications utilizing the
6
LT1055/LT1056
2k
LT1055/56 AI05
OUTPUT
0.5ms/DIV
Output
LT1055/56 AI08
9