WM8191

Advanced Information

WOLFSON MICROELECTRONICS LTD

AI Rev 3.1 April 2001

18

MCLK

VSMP

(VDEL = 000) INTVSMP

POSNNEG = 1

(VDEL = 001) INTVSMP

(VDEL = 010) INTVSMP

(VDEL = 011) INTVSMP

(VDEL = 100) INTVSMP

(VDEL = 101) INTVSMP

(VDEL = 110) INTVSMP

(VDEL = 111) INTVSMP

POSNNEG = 0

(VDEL = 000) INTVSMP

(VDEL = 001) INTVSMP

(VDEL = 010) INTVSMP

(VDEL = 011) INTVSMP

(VDEL = 100) INTVSMP

(VDEL = 101) INTVSMP

(VDEL = 110) INTVSMP

(VDEL = 111) INTVSMP

INPUT

PINS

Figure 18 Internal VSMP Pulses Generated by Programmable VSMP Detect Circuit

REFERENCES

The ADC reference voltages are derived from an internal bandgap reference, and buffered to pins

VRT and VRB, where they must be decoupled to ground. Pin VRX is driven by a similar buffer, and

also requires decoupling. The output buffer from the RLCDAC also requires decoupling at pin

VRLC/VBIAS.

POWER SUPPLY

The WM8191 can run from a 5V single supply or from split 5V (core) and 3.3V (digital interface)

supplies.

POWER MANAGEMENT

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

on or off completely by the EN bit. Alternatively, when control bit SELPD is high, only blocks selected

by further control bits (SELDIS[3:0]) are powered down. This allows the user to optimise power

dissipation in certain modes, or to define an intermediate standby mode to allow a quicker recovery

into a fully active state. In Line-by-Line operation, the green and blue channel PGAs are

automatically powered down.

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

control interface inputs remain active. Table 3 summarises the power down control bit functions.

EN

SELDPD

00

Device completely powers down.

10

Device completely powers up.

X1

Blocks with respective SELDIS[3:0] bit high are disabled.

Table 3 Power Down Control