SGM8049-1 Datasheet, PDF (9/19 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)
In unity-gain inverting configuration, phase margin can
be reduced by the reaction between the capacitance at
the operational amplifier input and the gain setting
resistors. Best performance is achieved by using
smaller valued resistors. However, when large valued
resistors cannot be avoided, a small (4pF to 6pF)
capacitor, C_FB, can be inserted in the feedback, as
shown in Figure 4. This configuration significantly
reduces overshoot by compensating the effect of
capacitance, C_IN, which includes the amplifier input
capacitance and printed circuit board (PCB) parasitic
capacitance.
RIN
VIN
CIN
CFB
RF
-
SGM8049-1
+
VOUT
Figure 4. Improving Stability for Large RF and RIN
Figure 5 through Figure 9 illustrate some low power application examples.
R3
R2
+2.7V
-
SGM8049-1
VIN
+
R1
66.5Ω
C1
1.5nF
+2.7V
+VS
Low Power MCU
A0+
16-Bit
ADC
+2.7V
Voltage
Reference
C2
VREF
-VS
1μF
Figure 5. Unipolar Signal Chain Configuration
VEX
RR
RR
R1
VS
-
SGM8049-1
VOUT
+
R1
VREF
Figure 6. Single Operational Amplifier Bridge Amplifier
SG Micro Corp
www.sg-micro.com
NOVEMBER 2015
9