WM8974GEFL/V Wolfson Microelectronics, WM8974GEFL/V Datasheet - Page 47

• Manufacturer Part Number: WM8974GEFL/V
• Description: Audio CODECs Mono Codec with Spkr
• Manufacturer: Wolfson Microelectronics

Specifications of WM8974GEFL/V

• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• Package / Case: QFN-24
• Minimum Operating Temperature: - 25 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Production Data
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OUTPUT SWITCH
Table 45 Output Switch Operation (GPIOSEL=001)
THERMAL SHUTDOWN
Table 46 Thermal Shutdown
SPEAKER OUTPUT
Figure 22 Speaker Output Connection
When the device is configured with a 2-wire interface the CSB/GPIO pin can be used as a switch
control input to automatically disable the speaker outputs and enable the mono output. For example
when a line is plugged into a jack socket. In this mode, enabled by setting GPIOSEL=001, pin
CSB/GPIO switches between mono and speaker outputs (e.g. when pin 12 is connected to a
mechanical switch in the headphone socket to detect plug-in). The GPIOPOL bit reverses the
polarity of the CSB/GPIO input pin.
Note that the speaker outputs and the mono output must be enabled for this function to work (see
Table 45). The CSB/GPIO pin has an internal de-bounce circuit when in this mode in order to
prevent the output enables from toggling multiple times due to input glitches. This debounce circuit
is clocked from a slow clock with period 2
The speaker outputs can drive very large currents. To protect the WM8974 from overheating a
thermal shutdown circuit is included. The thermal shutdown can be configured to produce an
interrupt when the device reaches approximately 125
SPKOUTP/N can differentially drive a mono 8Ω Bridge Tied Load (BTL) speaker as shown below.
0
0
0
0
1
1
1
1
R49
Output control
GPIOPOL
REGISTER
ADDRESS
0
0
1
1
0
0
1
1
CSB/GPIO
1
BIT
TSDEN
LABEL
X
X
0
1
X
X
0
1
SPKNEN/
SPKPEN
21
1
x MCLK, enabled using the SLOWCLKEN register bit.
DEFAULT
1
X
1
X
0
X
0
X
MONOEN
o
C. See General Purpose Input/Output section.
Thermal Shutdown Enable
0 : thermal shutdown disabled
1 : thermal shutdown enabled
No
No
No
Yes
No
No
No
Yes
SPEAKER
ENABLED
PD, Rev 4.5, September 2008
DESCRIPTION
No
Yes
No
No
No
Yes
No
No
ENABLED
OUTPUT
MONO
WM8974
47