WM8255 datasheet(36/49 Pages) CIRRUS

36 / 49 page

Production Data

WM8255

PD, Rev 4.7, August 2013

REFERENCES

The ADC reference voltages are derived from an internal band-gap reference, and buffered to pins

VRT and VRB, where they must be decoupled to ground. The output buffer from the RLCDAC also

requires decoupling at pin VRLC/VBIAS when this is configured as an output.

POWER SUPPLY

The WM8255 operates from either a 5.75V (AVDD1) supply or a 3.3V (AVDD2).

POWER MANAGEMENT

The WM8255 has a power management system to detect the presence and correct level of the power

supplies AVDD1, AVDD2 and DVDD.

With reference to Figure 28, the WM8255 is partitioned into three power domains, a digital domain

AVDD2. In the digital domain, until DVDD has reached the correct level, a Power On Reset (POR)

shall disable the WM8255. The LDO voltage regulator and AFE voltage references shall be enabled

and allowed to power up as AVDD1 is applied when the POR released. With AVDD1, AVDD2 and

AFE voltage references at the correct level a system enable is set and WM8255 shall power up in a

controlled manner.

Figure 28 Power Management System

Power management for the device is performed via the Control Interface. The device can be powered

on or off completely by setting the EN bit low.

All the internal registers maintain their previously programmed value in power down mode and the

Control Interface inputs remain active.

WM8255 датащи(PDF) 36 Page - Cirrus Logic