TLC320AC01C Datasheet, PDF (49/90 Pages) Texas Instruments – Single-Supply Analog Interface Circuit

4 Parameter Measurement Information
R
IN + or AUX IN +
R
IN – or AUX IN –
Rfb
_
+
_
+
Rfb
To Multiplexer
Rfb = R for DS03 = 0 and DS02 = 1
Rfb = 2R for DS03 = 1 and DS02 = 0
Rfb = 4R for DS03 = 1 and DS02 = 1
R = 100 kΩ nominal
Figure 4 – 1. IN + and IN – Gain-Control Circuitry
Table 4 – 1. Gain Control (Analog Input Signal Required for
Full-Scale Bipolar A /D-Conversion 2s Complement)^†
INPUT CONFIGURATION
CONTROL REGISTER 4
DS03
DS02
ANALOG INPUT‡
A /D CONVERSION
RESULT
0
0
All
Squelch
Differential configuration
Analog input = IN + – IN –
0
1
VID = ± 3 V
± Full scale
= AUX IN + – AUX IN –
1
0
VID = ± 1.5 V
± Full scale
1
1
VID = ± 0.75 V
± Full scale
0
0
All
Squelch
Single-ended configuration§
Analog input = IN + – VMID
= AUX IN + – VMID
0
1
VI = ± 1.5 V
± Half scale
1
0
VI = ± 1.5 V
± Full scale
1
1
VI = ± 0.75 V
± Full scale
† _{VDD = 5 V}
‡ _{VID = differential input voltage, VI = input voltage referenced to ADC VMID with IN – or AUX IN – connected to}
ADC VMID. In order to minimize distortion, it is recommended that the analog input not exceed 0.1 dB below full scale.
§ _{For single-ended inputs, the analog input voltage should not exceed the supply rails. All single-ended inputs should be}
referenced to the internal reference voltage, ADC VMID, for best common-mode performance.
4–1