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Wolfson Microelectronics

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© 1996 Wolfson Microelectronics

Production Data

Sept 1996 Rev 2.1

8-Bit ADCs with Serial Interface and

Differential or Dual Inputs

Description

WM0831 and WM0832 are 8-bit analogue to digital

converters (ADC) with serial I/O interfaces, providing a

choice of input configurations in 8-pin SO or DIP packages.

WM0831 has a differential input, also configurable as a

single ended input. A-D conversion results are serially

output on Data Out (DO) under the control of clock and chip

select inputs. The device has a separate voltage reference

input.

WM0832's two input multiplexer is configurable via the Data

In (DI) serial input, as two single ended inputs or a single

differential input. The voltage reference operates

ratiometrically and is internally connected to the VCC pin.

Conversion is initiated by bringing and holding chip select

low while providing a clock input. With WM0831's fixed

input configuration, the conversion result is output at DO on

the clock's falling edges in MSB to LSB order.

With WM0832's configurable input multiplexer, data is input

to DI on the rising edges of the clock to setup the Mux and

initiate conversion. Conversion results appear serially at

DO on the falling edges of the clock, first in MSB to LSB

order, and then repeated in LSB to MSB order.

WM0831/2 operate on 5V or 3.3V supply voltages and are

available in small outline and DIP packages for commercial

(0 to 70

Features

•

Functionally Equivalent to National Semiconduc-

tor ADC0831 and ADC0832

•

WM0831: Differential or single ended input

•

WM0832: Two single ended inputs or a single

differential input

•

Ratiometric reference input (fixed for WM0832)

•

Serial I/O interface

•

Input range 0 to Vcc with Vcc Reference

•

8 pin package, SO or DIP

•

5V and 3.3V variants

•

Total Unadjusted Error: ± 1 LSB

•

8-bit resolution

•

32

µµµµµs conversion time at fclock = 250 kHz

Applications

•

Embedding with remote sensors

•

Equipment health monitoring

•

Automotive

•

Industrial control

Block Diagrams

WM0831

WM0832

GND

CH0

CH1

DI

CLK

CS

DO

Vcc

Start Conv

Mux Select

Input Latch

Internal CS

Output Shift

Register

Comparator

WM0832

DAC

&

SAR

Logic

Input

MUX

Output

Latch

Comparator

WM0831

DAC

&

SAR

Logic

GND

IN+

IN-

CLK

CS

DO

Vcc

WM0831, WM0832