LTC1051/LTC1053
TYPICAL APPLICATIO S
Obtaining Ultralow V
OS
Drift and Low Noise
B
+
5
2
+
–
–
3
1/2
LTC1051
5V
1
R4
6
1/2
LTC1051
C1
C2
+
R1
1
R5
R2
R3
3
+
A1
8
6
OUT
–
A
2
–
A1
LT1007
LT1012*
R1
3k
750Ω
R2
2k
57Ω
R3
340k
250k
* Interchange connections A and B .
** Noise measured in a 10 sec window. Peak-to-peak noise was also measured for 10 continuous minutes: With the LT1007 op amp the recorded noise was less than 0.2µV
P-P
for both DC-1Hz
and DC-10Hz.
V
S
=
±5V
0.2µV/DIV
U
7
OUT
The dual chopper op amp buffers the inputs of A1 and
corrects its offset voltage and offset voltage drift. With the
R, C values shown, the power-up warm up time is typically
20 seconds. The step response of the composite amplifier
does not present settling tails. The LT1007 should be used
when extremely low noise; V
OS
and V
OS
drift are sought
when the input source resistance is low—for instance a
350Ω strain gauge bridge. The LT1012 or equivalent
should be used when low bias current (100pA) is also
required in conjunction with DC to 10Hz low noise and low
V
OS
and V
OS
drift. The measured typical input offset
voltages were less than 2µV.
1051/53 AC01a
R4
10k
10k
R5
100k
100k
C1
0.01µF
0.01µF
C2
0.001µF
0.001µF
e
OUT
(DC – 1Hz)**
0.1µV
P-P
0.3µV
P-P
e
OUT
(DC – 10Hz)**
0.15µV
P-P
0.4µV
P-P
LTC1051/LT1007 Peak-to-Peak Noise
DC TO 1Hz
NOISE
DC TO 10Hz
NOISE
1 SEC/DIV
1051/53 AC01b
10513fa
11
LINER [ LINEAR TECHNOLOGY ]
