WM8900LGEFK/RV Wolfson Microelectronics, WM8900LGEFK/RV Datasheet - Page 56

• Manufacturer Part Number: WM8900LGEFK/RV
• Description: Audio CODECs Ultra Low Power Hi-Fi CODEC
• Manufacturer: Wolfson Microelectronics

Specifications of WM8900LGEFK/RV

• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

WM8900
ULTRA-LOW POWER GROUND-REFERENCED HEADPHONE OUTPUT
Figure 20 Ultra-Low Power Ground-Referenced Headphone Output
w
WM8900
Charge Pump
The WM8900 headphone amplifier architecture offers highly efficient DAC playback at typical
listening levels. A level-shifting charge pump enables the headphone output to be ground
referenced, eliminating the need for large DC blocking capacitors on the output. Class G operation
provides additional benefits to power consumption. Typical power consumption figures are detailed
in Table 2, Table 3, Table 4,Table 5 and Table 6.
The headphone amplifier configuration is illustrated in Figure 20.
The Charge Pump and the Headphone Amplifier are described separately in the following two
sections.
CHARGE PUMP
The level shifting charge pump has two outputs (VPOS and VNEG) and two inputs (CPVDDHI and
CPVDDLO). The input voltage selection is automatically determined by the output volume required.
For correct functionality, CPVDDHI should be higher than CPVDDLO.
The positive output, VPOS, generated by the charge pump will be half the input voltage. The
negative output, VNEG, will be a negative voltage of the same magnitude. The Charge Pump is
enabled by CP_ENA, as defined in Table 40.
The charge pump requires SYSCLK to be present at all times when the headphone amplifier is in
use.
Headphone
Driver
LINEOUT2R
LINEOUT2L
HPINL
HPL
HPR
HPINR
HPGND
0.47uF
0.47uF
PD, August 2008, Rev 4.0
Production Data
56
Headphone
Output