Datasheet

LTC2057/LTC2057HV
24
2057f
For more information www.linear.com/LTC2057
Typical applicaTions
Paralleling Choppers to Improve Noise
–
+
R5
R2
R1
R1
LTC2057
V
IN
V
OUT
2057 TA04
–
+
R5
R2
LTC2057
R1
–
+
R5
R2
LTC2057
R1
DC TO 10Hz NOISE =
WHERE N IS THE NUMBER OF PARALLELED INPUT AMPLIFIERS.
FOR N = 4, DC TO 10Hz NOISE = 100nV
P-P
, e
n
= 5.5nV/√Hz, i
n
= 340fA/√Hz, I
B
< 800pA (MAX).
R
5
SHOULD BE A FEW HUNDRED OHMS TO ISOLATE AMPLIFIER OUTPUTS WITHOUT
CONTRIBUTING SIGNIFICANTLY TO NOISE OR I
B
-INDUCED ERROR.
, i
n
= √N • 170fA/√Hz, I
B
< N • 200pA (MAX), e
n
=
200nV
P-P
√N
–
+
R5
R2
LTC2057
R3
–
+
R4
LTC2057
11nV/√Hz
√N
A
V
= •
R2
R1
+ 1
R4
R3
+ 1
>> √N FOR OUTPUT AMPLIFIER NOISE TO BE INSIGNIFICANT.
R2
R1
+ 1