LT1991
TYPICAL PERFOR A CE CHARACTERISTICS
Small Signal Transient Response
GAIN = 1
50mV/DIV
5µs/DIV
PI FU CTIO S
(Difference Amplifier Configuration)
P1 (Pin 1):
Noninverting Gain-of-1 input. Connects a 450k
internal resistor to the op amp’s noninverting input.
P3 (Pin 2):
Noninverting Gain-of-3 input. Connects a 150k
internal resistor to the op amp’s noninverting input.
P9 (Pin 3):
Noninverting Gain-of-9 input. Connects a 50k
internal resistor to the op amp’s noninverting input.
V
EE
(Pin 4):
Negative Power Supply. Can be either ground
(in single supply applications), or a negative voltage (in
split supply applications).
REF (Pin 5):
Reference Input. Sets the output level when
difference between inputs is zero. Connects a 450k inter-
nal resistor to the op amp’s noninverting input.
BLOCK DIAGRA
U W
Small Signal Transient Response
GAIN = 3
Small Signal Transient Response
GAIN = 9
50mV/DIV
50mV/DIV
1991 G18
5µs/DIV
1991 G19
5µs/DIV
1991 G20
W
U
U
U
OUT (Pin 6):
Output. V
OUT
= V
REF
+ 1 • (V
P1
– V
M1
) + 3 •
(V
P3
– V
M3
) + 9 • (V
P9
– V
M9
).
V
CC
(Pin 7):
Positive Power Supply. Can be anything from
2.7V to 36V above the V
EE
voltage.
M9 (Pin 8):
Inverting Gain-of-9 input. Connects a 50k
internal resistor to the op amp’s inverting input.
M3 (Pin 9):
Inverting Gain-of-3 input. Connects a 150k
internal resistor to the op amp’s inverting input.
M1 (Pin 10):
Inverting Gain-of-1 input. Connects a 450k
internal resistor to the op amp’s inverting input.
Exposed Pad:
Must be soldered to PCB.
M1
10
M3
9
M9
8
50k
V
CC
7
450k
OUT
6
150k
4pF
450k
INM
450k
INP
LT1991
150k
50k
4pF
1
P1
2
P3
3
P9
4
V
EE
5
REF
1991fb
1991 BD
OUT
450k
7
LINEAR [ LINEAR INTEGRATED SYSTEMS ]
