Datasheet

12
LT1078/LT1079
10789fe
APPLICATIONS INFORMATION
WUU
U
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 two
and three op amp instrumentation amplifier configura-
tions shown in this data sheet are examples. Matching
characteristics are not 100% tested on the LT1078/LT1079.
Some specifications are guaranteed by definition. For
example, 70μV maximum offset voltage implies that mis-
match cannot be more than 140μV. 97dB (= 14μV/V)
CMRR means that worst-case CMRR match is 91dB
(= 28μV/V). However, Table 1 can be used to estimate the
expected matching performance at V
S
= 5V, 0V between
the two sides of the LT1078, and between amplifiers A and
D, and between amplifiers B and C of the LT1079.
Table 1
LT1078AC/LT1079AC/LT1078AM/LT1079AM LT1078C/LT1079C/LT1078M/LT1079M
PARAMETER 50% YIELD 98% YIELD 50% YIELD 98% YIELD UNITS
V
OS
Match, ΔV
OS
LT1078 30 110 50 190 μV
LT1079 40 150 50 250 μV
Temperature Coefficient ΔV
OS
0.5 1.2 0.6 1.8 μV/°C
Average Noninverting I
B
68610 nA
Match of Noninverting I
B
0.12 0.4 0.15 0.5 nA
CMRR Match 120 100 117 97 dB
PSRR Match 117 105 117 102 dB
Comparator Applications
The single supply operation of the LT1078/LT1079 and its
ability to swing close to ground while sinking current
lends itself to use as a precision comparator with TTL
compatible output.
4
V
S
= 5V, 0V 200μs/DIV
LT2078/79 • F03
2
0
0
–100
INPUT (mV) OUTPUT (V)
Figure 3. Comparator Rise Response
Time to 10mV, 5mV, 2mV Overdrives
V
S
= 5V, 0V 200μs/DIV
LT2078/79 • F04
0
100
0
INPUT (mV) OUTPUT (V)
4
2
Figure 4. Comparator Fall Response
Time to 10mV, 5mV, 2mV Overdrives