Cirrus Logic CS5509 - Manual (Page 20)

CS5509
20 DS125F3
Control Input Pins
CAL - Calibrate, Pin 3.
When taken high the same time that the CONV pin is taken high the converter will perform a
self-calibration which includes calibration of the offset and gain scale factors in the converter.
CONV - Convert, Pin 2.
The CONV pin initiates a calibration cycle if it is taken from low to high while the CAL pin is
high, or it initiates a conversion if it is taken from low to high with the CAL pin low. If CONV
is held high (CAL low) the converter will do continuous conversions.
BP/UP - Bipolar/Unipolar, Pin 6.
The BP/UP pin selects the conversion mode of the converter. When high the converter will
convert bipolar input signals; when low it will convert unipolar input signals.
Measurement and Reference Inputs
AIN+, AIN- - Differential Analog Inputs, Pins 7, 8.
Analog differential inputs to the delta-sigma modulator.
VREF+, VREF- - Differential Voltage Reference Inputs, Pins 9, 10.
A differential voltage reference on these pins operates as the voltage reference for the
converter. The voltage between these pins can be any voltage between 1.0 and 3.6 volts.
Power Supply Connections
VA+ - Positive Analog Power, Pin 11.
Positive analog supply voltage. Nominally +5 volts.
VD+ - Positive Digital Power, Pin 13.
Positive digital supply voltage. Nominally +5 volts or +3.3 volts.
GND - Ground, Pin 12.
Ground.