WM2632
Production Data
DEVICE DESCRIPTION
GENERAL FUNCTION
The WM2632 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 (0V to 2VREF Output), Gain = 2
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.
PROGRAMMABLE REFERENCE
The DAC reference can be sourced internally or externally under software control. If an external
reference voltage is applied to the REF pin, the device must be configured to accept this. If an
internal reference is selected, a voltage of 1.024V or 2.048 is available. The internal reference can
source up to 1mA and can therefore be used as an external system reference.
WOLFSON MICROELECTRONICS LTD
PD Rev 1.1 April 2001
8
WOLFSON [ WOLFSON MICROELECTRONICS PLC ]
