LT1001
APPLICATIONS INFORMATION
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
Improved Sensitivity Adjustment
7.5k
100kΩ
VOLTAGE GAIN = 50,000
(PEAK-TO-PEAK NOISE MEASURED IN 10 SEC INTERVAL)
1
7.5k
8
LT1001
7
6
OUTPUT
INPUT
2.2µF
TANTALUM
+
3.9k
1N914
0.01µF
300Ω
0.1µF
200Ω*
2N5160
2N3866
33Ω
1k
1.8k
2N4440
R
IN
1k
INPUT
10k
15pF
+
3
4
–15V
1001 F02
The device under test should be warmed up for three
minutes and shielded from air currents.
DC Stabilized 1000v/µsec Op Amp
+15V
2N5486
200pF
22µF TANTALUM
–15V
3
30k
+
LT1001
6
0.001µF
2
–
30k
470Ω
390Ω
2N3904
22Ω
2N5160
0.01µF
2N3866
200pF
3.9k
15-60pF
TUSONIX # 519-3188
200Ω*
1N914
300Ω
0.1µF
–15V
1001 F04
1k
R
f
FULL POWER
BANDWIDTH 8MHz
+
–
2
–
1k
+15V
U
W
U
U
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.
0.1Hz to 10Hz Noise Test Circuit
0.1µF
10Ω
2kΩ
LT1001
4.7
µF
+
LT1001
4.3k
22µF
SCOPE
×
1
R
IN
= 1MΩ
110k
DEVICE
UNDER
TEST
–
100k
24.3k
0.1
µF
2.2µF
1001 F03
+
2N3904
0.5Ω
OUTPUT
0.5Ω
2N3906
2N4440
22µF TANTALUM
1.2k
–
+
*ADJUST FOR
BEST SQUARE WAVE
AT OUTPUT
1001fb
7
LINER [ LINEAR TECHNOLOGY ]
