WM8983_10 Datasheet, PDF (24/124 Pages) Wolfson Microelectronics plc – Mobile Multimedia CODEC with 1W Speaker Driver

WM8983
Production Data
RECOMMENDED POWER UP/DOWN SEQUENCE
In order to minimise output pop and click noise, it is recommended that the WM8983 device is
powered up and down under control using the following sequences:
Power Up:
• Turn on external power supplies. Wait for supply voltage to settle.
• Set low bias mode, BIASCUT = 1.
• Mute all Outputs and set PGAs to minimum gain, R52 to R57 = 0x140h.
• Enable VMID independent current bias, POBCTRL = 1, DELEN = 1.
• Enable required outputs, DACs and mixers.
• Enable analogue bias, BIASEN, and VMID with required charge time e.g. VMIDSEL=01
= 100kΩ.
• Setup digital interface, input amplifiers, PLL, ADCs and DACs for desired operation.
• Unmute L/ROUT1 and set desired volume, e.g. for 0dB R52 and R53 = 0x139h.
• Unmute L/ROUT2 and set desired volume, e.g. for 0dB R54 and R55 = 0x139h.
• Disable VMID independent current bias, POBCTRL = 0, DELEN = 0.
Power Down:
• Disable Thermal shutdown
• Disable VMIDSEL=00 and BIASEN=0
• Wait for VMID to discharge
• Power off registers R1, R2, R3 = 0x000h
• Remove external power supplies
Note:
Charging time constant is determined by impedance selected by VMIDSEL and the value of
decoupling capacitor connected to VMID pin.
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PD, Rev 4.3, May 2010
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