WM2608

Production Data

WOLFSON MICROELECTRONICS LTD

PD Rev 1.0 April 2001

8

DEVICE DESCRIPTION

GENERAL FUNCTION

The WM2608 is an octal 10-bit, voltage output DAC. It contains a serial interface, control logic for

speed and power down, a programmable voltage reference, and eight digital to analogue converters.

Each converter uses a resistor string network buffered with an op amp to convert 10-bit digital data to

analogue voltage levels (see Block Diagram). The output voltage is determined by the reference

input voltage and the input code according to the following relationship:

Output voltage =

()

1024

2

CODE

INPUT

OUTPUT

11 1111 1111

()

1024

1023

2

REF

V

::

10 0000 0001

()

1024

511

2

REF

V

10 0000 0000

()

REF

REF

V

V

=

1024

512

2

01 1111 1111

()

1024

511

2

REF

V

::

00 0000 0001

()

1024

1

2

REF

V

00 0000 0000

0V

Table 1 Binary Code Table

POWER ON RESET

An internal power-on-reset circuit resets the DAC register to all 0s on power-up.

BUFFER AMPLIFIER

The output buffer has a near rail-to-rail output with short circuit protection and can reliably drive a

2k

Ω load with a 100pF load capacitance.