WM8961
Pre-Production
REGISTER ADDRESS
BIT
LABEL
VMIDSEL
DEFAULT
DESCRIPTION
R25 (19h)
8:7
00
VMID Divider Enable and Select
Power Management (1)
00 = VMID disabled (for OFF mode)
01 = 2 x 50kΩ divider enabled (for normal
playback / record)
10 = 2 x 250kΩ divider enabled (for low-power
standby)
11 = 2 x 5kΩ divider enabled (for fast start-up)
6
VREF
0
Enable master bias current source
0 = Master bias current source disabled
1 = Master bias current source enabled
R28 (1Ch) Anti-pop
4
3
2
BUFDCOPEN
BUFIOEN
0
0
0
Enables fast startup bias generation
Internal VMID and fast bias enable
SOFT_ST
For anti-pops and clicks. VMID Slow start up.
Ramp up voltage
0 = function disabled
1 = slow VMID slew rate selected
Table 62 VMIDSEL Control Registers
The BUFDCCOPEN and BUFIOEN are used internally to enable the internal VMID and to enable the
internal fast start-up bias current. Users should enable both (set them to 1). The SOFT_ST bit can be
used to give a slow VMID ramp up voltage to reduce possibility of pops and clicks at start-up.
THERMAL SHUTDOWN AND STATUS
The speaker outputs can drive very large currents. To protect the WM8961 from overheating a
thermal shutdown circuit is included. If the device temperature reaches approximately 1500C and the
thermal shutdown circuit is enabled (TSDEN = 1; TSENSEN = 1) the speaker amplifiers (SPK_LP,
SPK_LN, SPK_RP and SPK_RN) will be disabled.
TSENSEN must be set to 1 to enable the temperature sensor when using the TSDEN thermal
shutdown function.
REGISTER ADDRESS
BIT
LABEL
DEFAULT
DESCRIPTION
Thermal Shutdown Enable
R23 (17h)
8
TSDEN
1
Additional Control (1)
0 = Thermal shutdown disabled
1 = Thermal shutdown enabled
(TSENSEN must be enabled for this function to
work)
R48 (30h)
1
TSENSEN
1
Temperature Sensor Enable
Additional Control (4)
0 = Temperature sensor disabled
1 = Temperature sensor enabled
Table 63 Thermal Shutdown
In addition to the thermal shutdown registers, there are 2 status (read only) registers which can be
used to check the status of the temperature sensor. These are the TEMP_WARN and TEMP_SHUT
status bits
REGISTER ADDRESS
BIT
LABEL
DEFAULT
DESCRIPTION
R47 (2Fh) Pwr Mgmt (3)
1
TEMP_SHUT
0
Read only status of temperature sensor
triggers at 145 degrees C
0
TEMP_WARN
0
Read only status of temperature sensor – triggers
at 125 degrees C
Table 64 Thermal Status
PP, August 2009, Rev 3.1
w
79
WOLFSON [ WOLFSON MICROELECTRONICS PLC ]
