WM2629
Production Data
DEVICE DESCRIPTION
GENERAL FUNCTION
The WM2629 is an octal 8-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 8-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:
CODE
Output voltage = 2
(VREF
)
256
INPUT
OUTPUT
255
256
1111
1111
2
2
(
VREF
)
:
:
129
256
1000
1000
0111
0001
(VREF
)
128
256
0000
1111
2
(
VREF
)
= VREF
127
256
2
2
(VREF
)
:
:
1
0000
0000
0001
(VREF
)
256
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
2kΩ load with a 100pF load capacitance.
WOLFSON MICROELECTRONICS LTD
PD Rev 1.0 April 2001
8
WOLFSON [ WOLFSON MICROELECTRONICS PLC ]
