
10
LT1124/LT1125
U
S
A
O
PPLICATI
TYPICAL
Gain 1000 Amplifier with 0.01% Accuracy, DC to 1Hz
Gain Error vs Frequency Closed-Loop Gain = 1000
–
+
OUTPUT
1124/25 TA03
365
1%
INPUT
15k
5%
340k
1%
20k
TRIM
15V
1/2 LT1124
–15V
RN60C FILM RESISTORS
THE HIGH GAIN AND WIDE BANDWIDTH OF THE LT1124/LT1125, IS USEFUL IN LOW
FREQUENCY HIGH CLOSED-LOOP GAIN AMPLIFIER APPLICATIONS. A TYPICAL
PRECISION OP AMP MAY HAVE AN OPEN-LOOP GAIN OF ONE MILLION WITH 500kHz
BANDWIDTH. AS THE GAIN ERROR PLOT SHOWS, THIS DEVICE IS CAPABLE OF 0.1%
AMPLIFYING ACCURACY UP TO 0.3Hz ONLY. EVEN INSTRUMENTATION RANGE
SIGNALS CAN VARY AT A FASTER RATE. THE LT1124/LT1125 “GAIN PRECISION —
BANDWIDTH PRODUCT” IS 75 TIMES HIGHER, AS SHOWN.
4
7 (SO-8)
1 (N8)
6 (S0-8)
8 (N8)
3
2
FREQUENCY (Hz)
G
0.01
0.1
1.0
0.1
10
100
1124/25 TA04
0.001
1
GAIN ERROR =OPEN-LOOP GAIN
TYPICAL
PRECISION
OP AMP
LT1124/LT1125
Table 2. Guaranteed Performance, V
S
=
±
15V, T
A
= 25
°
C, Low Cost Devices
LT1124CN8
PARAMETER/UNITS
LT1125CN
Voltage Noise, 1kHz
100% Tested
Slew Rate
100% Tested
Gain Bandwidth Product
100% Tested
Offset Voltage
LT1124
LT1125
Offset Current
LT1124
LT1125
Bias Current
Supply Current/Amp
Voltage Gain, R
L
= 2k
Common Mode Rejection Ratio
Power Supply Rejection Ratio
SO-8 Package
Yes - LT1124
OP-27 GP
4.5
Sample Tested
1.7
Not Tested
5.0
Not Tested
100
–
75
–
80
5.67
0.7
100
94
Yes
OP-270 GP
–
No Limit
1.7
OP-470 GP
5.0
Sample Tested
1.4
UNITS
nV/
√
Hz
4.2
2.7
V/
μ
s
8.0
–
–
MHz
No Limit
250
–
20
–
60
3.25
0.35
90
104
No
No Limit
–
1000
–
30
60
2.75
0.4
100
105
–
100
140
20
30
30
2.75
1.5
106
110
μ
V
μ
V
nA
nA
nA
mA
V/
μ
V
dB
dB
Table 2 summarizes the performance of the LT1124/
LT1125 compared to the low cost grades of alternate
approaches.
The comparison shows how the specs of the LT1124/
LT1125 not only stand up to the industry standard OP-27,
but in most cases are superior. Normally dual and quad
performance is degraded when compared to singles, for
the LT1124/LT1125 this is not the case.
PERFOW
U
W
U