WM0831, WM0832
Pin Descriptions
WM0831
WM0832
Pin
1
Name
CS
Type
Digital
Function
Chip Select
(active low)
Pin
1
Name
CS
Type
Digital
Function
Chip Select
(active low)
2
3
4
5
IN+
IN-
Analogue input Positive differential
2
3
4
CH0 Analogue input
CH1 Analogue input
GND Supply
Channel 0 input to
multiplexer (MUX)
Channel 1 input to
multiplexer (MUX)
Analogue and
digital ground
Data input
input
Analogue input Negative differential
input
GND Supply
Analogue and digital
ground
VREF Analogue input Voltage reference
input
5
6
7
8
DI
DO
Digital input
Digital input
Data Output
Clock input
6
7
8
DO
CLK Digital input
Supply
Digital input
Data Output
Clock input
Positive supply
voltage
CLK Digital input
VCC/VREF Supply/Analogue I/P Positive supply
voltage and
VCC
voltage(ratiometric)
reference input
Multiplexer / Package Options
Number of Analogue Channels
Device
No
Number of
Package Pins
Single Ended
Differential
WM0831
WM0832
1
2
1
1
8
8
Functional Description
Input and Multiplexer Operation and Addressing
WM0831 has two inputs IN+ and IN- configured for
differential operation, single ended operation is achieved
by grounding IN- to an analogue common or GND.
WM0832 uses an input multiplexer scheme with two input
channels, configurable for single-ended or differential
operation. The single ended input uses the GND pin as its
analogue ground reference.
For WM0832 prior to the start of every conversion the input
configuration is assigned during the MUX addressing
sequence by serially shifting data into the Data Input (DI) on
the second and third rising edges of the clock input. The
MUX address selects which analogue inputs are enabled,
either single-ended or differential. For differential inputs the
polarity of the inputs are also assigned. The MUX
addressing table gives full details of input assignments.
Because WM0831 has only one differential input of fixed
polarity it does not require addressing.
WM0831/2 uses a successive approximation routine to
perform A/D conversion and employs a sample data
comparator structure which always performs conversion
on a differential voltage. Conversion takes place on the
voltage difference between assigned “+” and “-” inputs and
the converter expects the “+” input to be the most positive,
if the “+” input is more negative than “-” then the converter
gives an all zeros output. Assignment of WM0832 inputs
is made for a single-ended signal between an “+” input
and (analogue) ground (GND), or for a differential input
between CH0 and CH1 inputs of either polarity.
WM0832 MUX Addressing
MUX Address
SGL/DIF
Channel Number
ODD/EVEN
0
1
Differential MUX Mode
0
0
0
1
+
-
-
+
Single Ended MUX Mode
1
1
0
1
+
+
Wolfson Microelectronics
10
WOLFSON [ WOLFSON MICROELECTRONICS PLC ]
