LT1168 Linear Technology, LT1168 Datasheet - Page 14

• Manufacturer Part Number: LT1168
• Description: Low Power/ Single Resistor Gain Programmable/ Micropower Precision Instrumentation Amplifier
• Manufacturer: Linear Technology

APPLICATIONS
LT1168
Low I
Dissipation
The LT1168’s low supply current, low supply voltage
operation and low input bias currents allow it to fit nicely
into battery-powered applications. Low overall power
dissipation necessitates using higher impedance bridges.
The single supply pressure monitor application, Figure 7,
shows the LT1168 connected to the differential output of
TYPICAL APPLICATIONS
14
B
Favors High Impedance Bridges, Lowers
LT1634CCZ-1.25
3.5k
3.5k
U
5V
392k
R5
3.5k
3.5k
INFORMATION
U
50k
50k
2
1
R4
R3
1
G = 200
249
100k
3
2
R8
+
–
U
LT1490
W
1/2
5
6
V
3
1
8
2
S
8
4
+
–
LT1490
+
–
Figure 7. Single Supply Pressure Monitor
1/2
R6
1k
1
LT1168
4
U
4
2
6
50k
R7
Single Supply Barometer
LUCAS NOVA SENOR
7
NPC-1220-015-A-3L
7
5k
R
5k
SET
5
(0.02% RATIO MATCH)
5
BI TECHNOLOGIES
6
67-8-3 R40KQ
5k
5k
–
a 3.5k bridge. The picoampere input bias currents keep the
error caused by offset current to a negligible level. The
LT1112 level shifts the LT1168’s reference pin and the
ADC’s analog ground pins above ground. The LT1168’s
and LT1112’s combined power dissipation is still less than
the bridge’s. This circuit’s total supply current is just
2.2mA.
+
40k
20k
40k
1
3
0.6% ACCURACY AT 25 C
1.7% ACCURACY AT 0 C TO 60 C
V
S
= 8V TO 30V
+
–
R1
825
R2
12
LT1112
1/2
2
8
1
3
–
+
LT1168
G = 60
4
V
S
7
REF
IN
AGND
LTC
5
VOLTS
2.800
3.000
3.200
ADC
®
1286
6
INCHES Hg
OUTPUT
DIGITAL
28.00
30.00
32.00
DATA
TO
4-DIGIT
DVM
1168 TA05
1168 TA03