WM8983GEFL/V Wolfson Microelectronics, WM8983GEFL/V Datasheet - Page 47

• Manufacturer Part Number: WM8983GEFL/V
• Description: Audio CODECs Mbl Multimedia CODEC w/ 1W Speaker Driver
• Manufacturer: Wolfson Microelectronics

Specifications of WM8983GEFL/V

• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• Package / Case: QFN-32
• Minimum Operating Temperature: - 25 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Production Data
LIMITER MODE
Figure 24 ALC Limiter Mode Operation
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ALC LIMITER MODE INITIALISATION SEQUENCE
In limiter mode, the ALC will reduce peaks that go above the threshold level, but will not increase the
PGA gain beyond the starting level. The starting level is the PGA gain setting when the ALC is
enabled in limiter mode. If the ALC is started in limiter mode, this is the gain setting of the PGA at
startup. If the ALC is switched into limiter mode after running in ALC mode, the starting gain will be
the gain at switchover. The diagram below shows an example of limiter mode.
In order to correctly initialise the ALC in limiter mode, the following sequence of register writes is
required. MCLK must be applied during the initialisation sequence
1. R–5 - Set left input PGA gain (INPPGAVOLL) to level required for operation.
2. R–6 - Set right input PGA gain (INPPGAVOLR) to level required for operation.
3. R–4 - Enable analogue inputs as required.
4. –2 - Disable input PGA (INPPGAEN = 0).
5. R59 = 0x00–3 - Enable ALC test mode.
6. R–2 - Set ALCMAXGAIN and ALCMINGAIN to the level required for operation.
7. R–3 - Set limiter level (ALCLVL) to the level required for operation.
8. R34 = 0x00–0 - Enable ALC mode (ALCMODE = 0).
9. Insert 1ms delay to allow input PGA gain update by the limiter circuit.
PD, Rev 4.3, May 2010
WM8983
47