Datasheet

LT1028/LT1128
17
1028fb
Typical applicaTions
Paralleling Amplifiers to Reduce Voltage Noise
1028 TA05
–
+
1.5k
A1
LT1028
470Ω
OUTPUT
–
+
7.5Ω
4.7k
–
+
1.5k
470Ω
7.5Ω
–
+
1.5k
470Ω
7.5Ω
A2
LT1028
An
LT1028
LT1028
OUTPUT NOISE
n • 200
2µV
√5
1. ASSUME VOLTAGE NOISE OF LT1028 AND 7.5Ω SOURCE RESISTOR = 0.9nV/√Hz.
2. GAIN WITH n LT1028s IN PARALLEL = n • 200.
3. OUTPUT NOISE = √n • 200 • 0.9nV/√Hz.
4. INPUT REFERRED NOISE = = nV/√Hz.
5. NOISE CURRENT AT INPUT INCREASES √n TIMES.
6. IF n = 5, GAIN = 1000, BANDWIDTH = 1MHz, RMS NOISE, DC TO 1MHz = = 0.9µV.
0.9
√n