LT1125 Linear Technology Corporation, LT1125 Datasheet - Page 8

• Manufacturer Part Number: LT1125
• Description: Dual/quad Low Noise, High Speed Precision Op Amps
• Manufacturer: Linear Technology Corporation

LT1124/LT1125
A
The LT1124 may be inserted directly into OP-270 sockets.
The LT1125 plugs into OP-470 sockets. Of course, all
standard dual and quad bipolar op amps can also be
replaced by these devices.
Matching Specifications
In many applications the performance of a system de-
pends on the matching between two op amps, rather than
the individual characteristics of the two devices. The three
op amp instrumentation amplifier configuration shown in
this data sheet is an example. Matching characteristics are
not 100% tested on the LT1124/LT1125.
Some specifications are guaranteed by definition. For
example, 70µV maximum offset voltage implies that mis-
match cannot be more than 140µV. 112dB (= 2.5µV/V)
CMRR means that worst case CMRR match is 106dB
PARAMETER
V
Temperature Coefficient Match
Average Noninverting I
Match of Noninverting I
CMRR Match
PSRR Match
8
Table 1. Expected Match
OS
PPLICATI
Match, ∆V
OS
O
LT1125
LT1124
B
B
U
S
I FOR ATIO
U
50% YIELD
0.35
126
127
20
30
6
7
W
LT1124AC/AM
LT1125AC/AM
Figure 1. Test Circuit for Offset Voltage
and Offset Voltage Drift with Temperature
*RESISTORS MUST HAVE LOW
100Ω*
50k*
THERMOELECTRIC POTENTIAL
V
OUT
U
= 1000V
98% YIELD
–
+
50k*
110
150
115
118
1.0
18
22
OS
–15V
15V
(5µV/V). However, Table 1 can be used to estimate the
expected matching performance between the two sides of
the LT1124, and between amplifiers A and D, and between
amplifiers B and C of the LT1125.
Offset Voltage and Drift
Thermocouple effects, caused by temperature gradients
across dissimilar metals at the contacts to the input
terminals, can exceed the inherent drift of the amplifier
unless proper care is exercised. Air currents should be
minimized, package leads should be short, the two input
leads should be close together and maintained at the same
temperature.
The circuit shown in Figure 1 to measure offset voltage is
also used as the burn-in configuration for the LT1124/
LT1125, with the supply voltages increased to ±16V.
1124/25 F01
50% YIELD
V
OUT
123
127
0.5
30
50
7
8
LT1124C/M
LT1125C/M
98% YIELD
130
180
112
114
1.5
25
30
UNITS
11245fb
µV/°C
µV
µV
nA
nA
dB
dB