DAC101C081_16 Datasheet, PDF (23/40 Pages) Texas Instruments – DAC101C08xx 10-Bit Micro Power Digital-to-Analog Converter With an I2C-Compatible Interface

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10.2 Typical Application
DAC101C081, DAC101C081Q, DAC101C085
SNVS801B – APRIL 2012 – REVISED JANUARY 2016
120 pF
Pressure
Sensor
0.2 mV/Volt/PSI
+5
3
+
5
A2
4-
2
A_V = 100
+5 _LM4132-3.3
4
5
3
2 ^{.1 uF}
2
V_A
1
V_{OUT DAC101C081CIMK}
3
1 uF
1
100 K
2.02 K
.2 uF ¹⁸⁰
+5 +3.3
470 pF
1
10 9
2
V_REF
+IN
V_A
V_IO
ADC161S626
3 ^-IN
4,5
+5
100 K
3
-
5
A1
1
4+
2
.2 uF
180
470 pF
A1 and A2 = LMP7701
Figure 29. Pressure Sensor Gain Adjust
4 ^SDA
5 _SCL
6 ADR0
8 SCLK
7 DOUT
6 /CS
10.2.1 Design Requirements
A positive supply only data acquisition system capable of digitizing a pressure sensor output. In addition to
digitizing the pressure sensor output, the system designer can use the DAC101C081 to correct for gain errors in
the pressure sensor output by adjusting the bias voltage to the bridge pressure sensor.
10.2.2 Detailed Design Procedure
As shown in Equation 4, the output of the pressure sensor is relative to the imbalance of the resistive bridge
times the output of the DAC101C081, thus providing the desired gain correction.
Pressure Sensor Output = (DAC_Output × [(R2 / (R1 + R2) – (R4 / (R3 + R4)]
(4)
Likewise for the ADC161S626, Equation 5 shows that the ADC output is function of the Pressure Sensor Output
times relative to the ratio of the ADC input divided by the DAC101C081 output voltage.
ADC161S626 Output = (Pressure Sensor Output × 100 /(2 × VREF) ) × 2¹⁶
(5)
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