Datasheet

7
LT1001
1001fb
0.1Hz to 10Hz Noise Test Circuit
Offset Voltage Adjustment
The input offset voltage of the LT1001, and its drift with
temperature, are permanently trimmed at wafer test to a
low level. However, if further adjustment of Vos is neces-
sary, nulling with a 10k or 20k potentiometer will not
degrade drift with temperature. Trimming to a value other
than zero creates a drift of (Vos/300)µV/°C, e.g., if Vos is
–
+
LT1001
–
+
LT1001
100kΩ
2kΩ
100k
4.3k
110k
SCOPE
× 1
R
IN
= 1MΩ
0.1µF
4.7 µF
24.3k
10Ω
1001 F03
0.1 µF
22µF
VOLTAGE GAIN = 50,000
2.2µF
DEVICE
UNDER
TEST
(PEAK-TO-PEAK NOISE MEASURED IN 10 SEC INTERVAL)
Improved Sensitivity Adjustment
–
+
–15V
LT1001
+15V
2
3
7
6
OUTPUT
INPUT
1001 F02
4
8
7.5k
1k
7.5k
1
1001 F04
–
+
+
+–
+
2.2µF
TANTALUM
INPUT
1k
30k
3.9k
30k
390Ω
1.2k
0.5Ω
0.5Ω
470Ω
300Ω
1.8k
3.9k
300Ω
*ADJUST FOR
BEST SQUARE WAVE
AT OUTPUT
FULL POWER
BANDWIDTH 8MHz
200Ω*
200Ω*
22Ω
33Ω
2N3866
2N5160
2N5160
2N3904
2N4440
2N3866
+15V
2N4440
OUTPUT
2N3904
2N3906
1N914
1N914
6
3
15pF
10k
R
IN
1k
2
–15V
LT1001
0.01µF
22µF TANTALUM
22µF TANTALUM
0.1µF
0.1µF
–15V
200pF
0.001µF
0.01µF
200pF
2N5486
15-60pF
TUSONIX # 519-3188
1k
R
f
DC Stabilized 1000v/µsec Op Amp
adjusted to 300 µV, the change in drift will be 1 µV/°C. The
adjustment range with a 10k or 20k pot is approximately
±2.5mV. If less adjustment range is needed, the sensitivity
and resolution of the nulling can be improved by using a
smaller pot in conjunction with fixed resistors. The ex-
ample below has an approximate null range of ±100 µV.
APPLICATIONS INFORMATION
WUU
U
The device under test should be warmed up for three
minutes and shielded from air currents.