WM8983GEFL/RV Wolfson Microelectronics, WM8983GEFL/RV Datasheet - Page 70

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

Specifications of WM8983GEFL/RV

• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• Package / Case: QFN-32
• Minimum Operating Temperature: - 25 C

WM8983
Figure 37 Output Boost Mode with Direct Battery Connection
w
Figure 35 Non-Boost Mode Output Operation
SPEAKER BOOST MODE
To support speaker boost mode, AVDD2 should be at least 1.5*AVDD1. A higher AVDD2 will
improve THD performance at the expense of power consumption while lower AVDD2 will cause
clipping.
Variations in AVDD1 and AVDD2 should be taken into account when using speaker boost mode as
shown in Figure 35 and Figure 36.
LOUT2 and ROUT2 outputs can be connected directly to a Lithium battery to improve THD
performance in non-boost mode. When using a 4.2V lithium battery maximum power output is
achieved without using speaker boost and by setting ADVV1 = 3.6V.
Although direct battery connection is also possible in boost mode, the discharge characteristic of the
battery can lead to clipping after a relatively short period of time as shown in Figure 37. Reducing the
maximum permitted volume and keeping AVDD1 to a minimum will allow boost mode to operate for
longer.
As the full scale output falls close to AVDD1, it becomes more effective to use non-boost mode to
generate a louder output, although SPKBOOST should NOT be changed while the speaker output is
driving out a signal. As a general rule:
if AVDD2 - (AVDD1 * 0.75) > AVDD1 / 2 boost mode provides more power output;
if AVDD2 - (AVDD1 * 0.75) < AVDD1 / 2 non-boost mode provides more power output.
Figure 36 Boost Mode Output Operation
PD Rev 4.0 November 2006
Production Data
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