WM2630
Production Data
DEVICE DESCRIPTION
GENERAL FUNCTION
The WM2630 is an octal 12-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 12-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
)
4096
INPUT
OUTPUT
1111
1111
1111
4095
4096
2
(
(
VREF
)
)
:
:
1000
1000
0111
0000
0001
0000
1111
2049
4096
2
VREF
0000
1111
2048
4096
2
(
VREF
)
= VREF
2047
2
2
(
(
VREF
)
)
4096
:
:
0000
0000
0000
0001
0000
1
VREF
4096
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 February 2001
8
WOLFSON [ WOLFSON MICROELECTRONICS PLC ]
