LT1128 Linear Technology Corporation, LT1128 Datasheet - Page 14

• Manufacturer Part Number: LT1128
• Description: Ultra Low Noise Precision High Speed Op Amps
• Manufacturer: Linear Technology Corporation

LT1028/LT1128
TYPICAL APPLICATIO S
14
A
If C
can be achieved using the over-compensation terminal.
The Gain, Phase plot also shows that phase margin is
about 45 at gain of 10 (20dB). The following configura-
PPLICATI
LT1021-5
F
BRIDGE
Strain Gauge Signal Conditioner with Bridge Excitation
350
is only used to cut noise bandwidth, a similar effect
2
3
+
–
5.0V
LT1028
–15V
3
2
15V
7
4
+
–
LT1128
–15V
1.1k
O
7
4
6
U
THE LT1028’s NOISE CONTRIBUTION IS NEGLIGIBLE
COMPARED TO THE BRIDGE NOISE.
15V
50
S
6
–
+
LT1028
10pF
330
330
I FOR ATIO
U
10k
301k*
*RN60C FILM RESISTORS
1028/1128 AI11
U
10k
ZERO
TRIM
REFERENCE
OUTPUT
W
2
3
+
–
LT1028
–15V
15V
4
7
U
6
5k
GAIN
TRIM
1 F
49.9 *
30.1k*
1028/1128 TA05
0V TO 10V
OUTPUT
tion has a high ( 70%) overshoot without the 10pF
capacitor because of additional phase shift caused by the
feedback resistor – input capacitance pole. The presence
of the 10pF capacitor cancels this pole and reduces
overshoot to 5%.
Over-Compensation
The LT1028/LT1128 are equipped with a frequency over-
compensation terminal (Pin 5). A capacitor connected
between Pin 5 and the output will reduce noise bandwidth.
Details are shown on the Slew Rate, Gain-Bandwidth
Product vs Over-Compensation Capacitor plot. An addi-
tional benefit is increased capacitive load handling capa-
bility.
LT1021-10
28V
1k
+
–
LT1028
Low Noise Voltage Regulator
330
1000pF
10
LT317A
28V
2k
2k
+
10
2N6387
121
2.3k
PROVIDES PRE-REG
AND CURRENT
LIMITING
20V OUTPUT
1028/1128 TA04