LT1113 LINER [Linear Technology], LT1113 Datasheet - Page 13

• Manufacturer Part Number: LT1113
• Description: Dual Low Noise, Precision, JFET Input Op Amps
• Manufacturer: LINER [Linear Technology]

TYPICAL
B & K MODEL 4381
A
ACCELEROMETER
OR EQUIVALENT
PPLICATI
O
U
2
3
–
+
1/2 LT1113
S
–5V TO –15V
100M
R1
5V TO 15V
51
51
51
Paralleling Amplifiers to Reduce Voltage Noise
8
4
Accelerometer Amplifier with DC Servo
R3
2k
3
2
3
2
5
6
7
1
+
–
+
–
+
–
1/2 LT1113
1/2 LT1113
1/2 LT1113
1250pF
1/2 LT1113
–15V
2 F
A1
A2
An
C1
C2
15V
8
4
1k
1k
1k
–
+
18k
R2
6
5
1
1
7
1k
1k
1k
1. ASSUME VOLTAGE NOISE OF LT1113 AND 51 SOURCE RESISTOR = 4.6nV/ Hz
2. GAIN WITH n LT1113s IN PARALLEL = n • 200
3. OUTPUT NOISE = n • 200 • 4.6nV/ Hz
4. INPUT REFERRED NOISE =
5. NOISE CURRENT AT INPUT INCREASES n TIMES
6. IF n = 5, GAIN = 1000, BANDWIDTH = 1MHz, RMS NOISE, DC TO 1MHz =
2 F
C3
20M
20M
R4
R5
6
5
–
+
1/2 LT1113
–15V
10k
15V
OUTPUT
R4C2 = R5C3 > R1 (1 + R2/R3) C1
OUTPUT = 0.8mV/pC* = 8.0mV/g**
DC OUTPUT 2.7mV
OUTPUT NOISE = 6nV/ Hz AT 1kHz
*PICOCOULOMBS
**g = EARTH’S GRAVITATIONAL CONSTANT
8
4
OUTPUT NOISE
7
n • 200
OUTPUT
=
4.6
n
nV/ Hz
1113 • TA03
LT1113
13
9 V
5
1113 • TA04
= 4 V