Datasheet

INA326, INA327
16
SBOS222D
www.ti.com
FIGURE 16. Programmable ±5mA Current Source.
FIGURE 17. ±27V Output at 200mA Amplifier with 100µV Offset.
INA326
4
5
7
2
1
8
3
6
I
O
= ±5mA with
0.1µA stability.
+2.5V
−2.5V
I
O
0.1µF
V
REF
= +2.5V
R
I
= 200kΩ
10kΩ
49.9Ω
DAC
R
L
I
OUT
= 2
V
REF
− V
DAC
200kΩ
1 +
10kΩ
49.9Ω
INA326
4
4
5
7
7
2
1
8
3
2
3
6
6
+5V
−30V
+30V
I
B
10nF
2kΩ
1MΩ
R
I
= 1kΩ
20kΩ
V
I
20kΩ
R
F
= 100kΩ
OPA551
Internal charge pump in the INA326 allows
this node to swing 20mV below ground
without a negative supply.
Offset of the high- voltage op amp
is controlled by the INA326.
V
O
= –27V
V
OS
= –100µV at 200mA
G = − = −100V/V
R
F
R
I
NOTES: (1) The OPA551 is a 60V op amp. (2) The INA326 does not require a
negative supply to correct for negative V
OS
values from the high-voltage op amp.
(3) Voltage offset contribution of I
B
(OPA551) is 100pA • 2kΩ = 0.2µV.