WM8951L_07 WOLFSON [Wolfson Microelectronics plc], WM8951L_07 Datasheet - Page 33

• Manufacturer Part Number: WM8951L_07
• Description: Stereo ADC with Microphone Input and Clock Generator
• Manufacturer: WOLFSON [Wolfson Microelectronics plc]

Production Data
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OSCPD: Powers off the on board crystal oscillator. The MCLK input will function independently of the
Oscillator being powered down.
CLKOUTPD: Powers down the CLOCKOUT pin. This conserves power, reduces digital noise and RF
emissions if not required. CLKOUT is tied low when powered down.
The device can be put into a standby mode (STANDBY) by powering down all the audio circuitry
under software control as shown in Table 21. If the crystal oscillator and/or CLOKOUT pins are being
used to derive the system master clock, these should probably never be powered off in standby.
Provision has been made to independently power off these areas according to Table 21.
Table 21 Standby Mode
In STANDBY mode the Control Interface, a small portion of the digital and areas of the analogue
circuitry remain active. The active analogue includes the analogue VMID reference so that the
analogue line inputs remain biased to VMID. This reduces any audible effects caused by DC glitches
when entering or leaving STANDBY mode.
The device can be powered off by writing to the POWEROFF bit of the Power Down register. In
POWEROFF mode the Control Interface and a small portion of the digital remain active. The
analogue VMID reference is disabled. As in STANDBY mode the crystal oscillator and/or CLKOUT
pin can be independently controlled. Refer to Table 22.
Table 22 Poweroff Mode
Note:
For minimum power consumption unused control bits 3 and 4 should be set to ‘1’.
0
0
0
1
1
1
0
1
1
0
1
1
0
0
1
0
0
1
X
X
X
1
1
1
X
X
X
1
1
1
X
X
X
1
1
1
DESCRIPTION
STANDBY, but with Crystal Oscillator OS
and CLKOUT available
STANDBY, but with Crystal Oscillator OS
available, CLKOUT not-available
STANDBY, Crystal oscillator and CLKOUT
not-available.
DESCRIPTION
POWEROFF, but with Crystal Oscillator OS and
CLKOUT available
POWEROFF, but with Crystal Oscillator OS
available, CLKOUT not-available
POWEROFF, Crystal oscillator and CLKOUT
not-available.
PD Rev 4.1 December 2007
WM8951
33