AND8054 Datasheet, PDF (22/28 Pages) ON Semiconductor – Designing RC Oscillator Circuits with Low Voltage Operational Amplifiers and Comparators for Precision Sensor Applications

AND8054/D
MPS2907A
Q1
V_CC
V_{Q1_Base} = 0.1 V
R9
39 k
R10
39 k
V_CC/2
C1
240 pF
R1
39 k
V_CC/2
– ^A1
+
NCS2001
C2
240 pF
R2
39 k
V_CC/2
– ^A2
+
NCS2001
C3
47 pF
C4
47 pF
R4
3 Meg
R3
R5
5 k 20 Meg
– ^A3
V_CC/2 +
NCS2001
V_CC
R6
1k
V_CC/2
R8
R7 5 k
100 k
+ ^A4
–
NCS2200
NOTES:
1. Power Supply Voltages for amplifiers A1, A2, A3, and A4 is V_CC = 0.9 V, V_EE = 0 V
2. Capacitors C3 and C4 are typically the sensor capacitance; however, for test purposes two 47 pF capacitors were used to verify the
circuit.
3. V_{Max_Limit} = 0.8 V
Figure 26. Reference Design – Ratio Circuit
V_CC
R
R
+
–
C
V_CC/2
Figure 27. Low Output Impedance Reference Voltage
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