LT1127 Linear Technology Corporation, LT1127 Datasheet - Page 7

• Manufacturer Part Number: LT1127
• Description: Lt1127 - Dual/quad Decompensated Low Noise, High Speed Precision Op Amps
• Manufacturer: Linear Technology Corporation

APPLICATIO S I FOR ATIO
High Speed Operation
When the feedback around the op amp is resistive (R
pole will be created with R
capacitance (R
(C
TYPICAL
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.
IN
≈ 2pF). In low closed loop gain configurations and
Gain 1000 Amplifier with 0.01% Accuracy, DC to 5Hz
A
S
, C
PPLICATI
S
U
), and the amplifier input capacitance
365Ω
1%
INPUT
U
F
, the source resistance and
340k
1%
O
–
+
LT1126
U
W
+15V
–15V
15k
5%
S
TRIM
RN60C FILM RESISTORS
R
20k
S
U
C
S
OUTPUT
F
), a
–
+
C
F
C
with R
excess phase shift and even oscillation. A small capacitor
(C
R
completely removed.
IN
S
F
) in parallel with R
R
(C
F
S
S
+ C
1126-7 TA02
and R
IN
) = R
OUTPUT
F
1126-7 AI01
in the kilohm range, this pole can create
F
C
0.001
0.01
F
1.0
0.1
, the effect of the feedback pole is
F
0.1
PRECISION
eliminates this problem. With
TYPICAL
OP AMP
Closed Loop Gain = 1000
Gain Error vs Frequency
GAIN ERROR =
LT1126/LT1127
FREQUENCY (Hz)
1
CLOSED LOOP GAIN
OPEN LOOP GAIN
LT1126/LT1127
10
1126-7 TA03
11267fa
100
7