Production Data

WM2633

WOLFSON MICROELECTRONICS LTD

PD Rev 1.0 July 1999

11

PROGRAMMABLE INTERNAL REFERENCE

The 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 external reference is selected, the reference voltage input is buffered which makes the DAC

input resistance independent of code. The REF pin has an input resistance of 10M

Ω and an input

capacitance of typically 55pF. The reference voltage determines the DAC full-scale output.

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.

REF1

REF0

REFERENCCE

0

0

External (default)

0

1

1.024V

1

0

2.048V

1

1

External

Table 6 Programmable Internal Reference