LT1126AC View Datasheet(PDF) - Linear Technology
Part Name
Description
Manufacturer
LT1126AC Datasheet PDF : 12 Pages
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LT1126/LT1127
APPLICATIO S I FOR ATIO
High Speed Operation
When the feedback around the op amp is resistive (RF), a
pole will be created with RF, the source resistance and
capacitance (RS, CS), and the amplifier input capacitance
(CIN ≈ 2pF). In low closed loop gain configurations and
with RS and RF in the kilohm range, this pole can create
excess phase shift and even oscillation. A small capacitor
(CF) in parallel with RF eliminates this problem. With
RS (CS + CIN) = RF CF, the effect of the feedback pole is
completely removed.
CF
RF
–
CIN
RS
CS
+
OUTPUT
1126-7 AI01
TYPICAL APPLICATI S
Gain 1000 Amplifier with 0.01% Accuracy, DC to 5Hz
340k 15k 20k
1% 5% TRIM
365Ω
1%
+15V
–
INPUT
LT1126
+
–15V
OUTPUT
RN60C FILM RESISTORS
THE HIGH GAIN AND WIDE BANDWIDTH OF THE LT1126/LT1127 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 LT1126/LT1127 “GAIN PRECISION — BANDWIDTH PRODUCT” IS 330 TIMES HIGHER, AS SHOWN.
1126-7 TA02
Gain Error vs Frequency
Closed Loop Gain = 1000
1.0
TYPICAL
PRECISION
OP AMP
0.1
0.01
LT1126/LT1127
0.001
0.1
GAIN
ERROR
=
CLOSED LOOP GAIN
OPEN LOOP GAIN
1
10
100
FREQUENCY (Hz)
1126-7 TA03
11267fa
7
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