WM8993 datasheet(158/229 Pages) WOLFSON

Part #	WM8993

Description	Audio Hub CODEC for Multimedia Phones

PDF	229 Pages

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Manufacturer	WOLFSON [Wolfson Microelectronics plc]

Direct Link	http://www.wolfsonmicro.com

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WM8993

Production Data

PD, November 2010, Rev 4.0

158

POWER ON RESET

The WM8993 includes Power-On Reset (POR) circuits, which are used to reset the digital logic into a

default state after power up. The POR circuits derive their output from AVDD1, AVDD2 and DCVDD.

The internal POR

¯¯¯ signal is asserted low when AVDD1, AVDD2 and DCVDD are all below minimum

thresholds.

The specific behaviour of the circuit will vary, depending on relative timing of the supply voltages.

Typical scenarios are illustrated in Figure 69 and Figure 70.

Figure 69 Power On Reset timing – AVDD1/2 enabled first

Figure 70 Power On Reset timing - DCVDD enabled first

The POR

¯¯¯ signal is undefined until AVDD1 or AVDD2 has exceeded the minimum threshold, Vpora_on

Once this threshold has been exceeded, POR

¯¯¯ is asserted low and the chip is held in reset. In this

condition, all writes to the control interface are ignored. Once AVDD1, AVDD2 and DCVDD have all

WM8993 Datasheet(PDF) 158 Page - Wolfson Microelectronics plc