WM8711BL Wolfson Microelectronics, WM8711BL Datasheet - Page 19
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WM8711BL
Manufacturer Part Number
WM8711BL
Description
Ultra-Small Audio DAC
Manufacturer
Wolfson Microelectronics
Datasheet
1.WM8711BL.pdf
(43 pages)
Production Data
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DEVICE OPERATION
The recommended external components required to complete the application are shown in Figure 11.
Figure 11 Headphone Output Application Drawing
Recommended values are C1 = 220uF (10V electrolytic), R1 = 47k
C1 forms a DC blocking capacitor to isolate the dc of the HPOUT from the headphones. R1 form a
pull down resistor to discharge C1 to prevent the voltage at the connection to the headphones from
rising to a level that may damage the headphones.
DEVICE RESETTING
The WM8711BL contains a power on reset circuit that resets the internal state of the device to a
known condition. The power on reset is applied as DCVDD powers on and released only after the
voltage level of DCVDD crosses a minimum turn off threshold. If DCVDD later falls below a minimum
turn on threshold voltage then the power on reset is re-applied. The threshold voltages and
associated hysteresis are shown in the Electrical Characteristics table.
The user also has the ability to reset the device to a known state under software control as shown in
the table below.
When using the software reset. In 3-wire mode the reset is applied on the rising edge of CSB and
released on the next rising edge of SCLK. In 2-wire mode the reset is applied for the duration of the
ACK signal (approximately 1 SCLK period, refer to Figure 21).
Table 5 Software Control of Reset
0001111
Reset Register
REGISTER
ADDRESS
HPOUT
8:0
BIT
RESET
LABEL
C1
not reset
DEFAULT
AGND
R1
Reset Register
Writing 00000000 to register resets
device
DESCRIPTION
PD, Rev 4.1, April 2007
WM8711BL
AGND
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