SGM8049-1 Datasheet, PDF (10/19 Pages) SG Micro Corp – Rail-to-Rail I/O Operational Amplifiers

SGM8049-1/SGM8049-2
SGM8049-4
1.8V, 2.5µA, 120kHz,
Rail-to-Rail I/O Operational Amplifiers
APPLICATION INFORMATION (continued)
Load
V
ILOAD
RSHUNT
1Ω
R1
4.99kΩ
R3
4.99kΩ
+5V
R2
49.9kΩ
-
SGM8049-1
+
R4
48.7kΩ
Voltage ^3V
Reference
R6
71.5kΩ
Low Power
ADC
RN
56Ω
RN
I²C
56Ω
Stray Ground-Loop Resistance
R7
1.18kΩ
(PGA Gain = 4)
FS = 3.0V
NOTE: 1% resistors provide adequate common mode rejection at small ground-loop errors.
Figure 7. Low-side Current Shunt Monitor
RSHUNT
Load
RG
Zener⁽¹⁾
R1(2)
10kΩ
-
+VS
SGM8049-1
+
-VS
+5V
Dual NMOSFETs
biasing method is
shown.⁽³⁾
RBIAS
MOSFET rated to stand-off
supply voltage for up to
50V.
Output
RL
NOTES:
1. Zener rated for operational amplifier supply capability (that is, 5.6V for SGM8049-1/2/4).
2. Current-limiting resistor.
3. Choose Zener biasing resistor or dual NMOSFETs.
Figure 8. High-side Current Measurement
RG
VREF
R1
R2
R2
R1
VOUT
-
V2
SGM8049-1
+
-
SGM8049-1
+
V1
VOUT = (V1 – V2) (1 + R1/R2 + 2R1/RG) + VREF
Figure 9. Two Operational Amplifiers Low Power Instrumentation Amplifier
SG Micro Corp
www.sg-micro.com
NOVEMBER 2015
10