WM8740SEDS/V Wolfson Microelectronics, WM8740SEDS/V Datasheet - Page 20

• Manufacturer Part Number: WM8740SEDS/V
• Description: Audio D/A Converter ICs Stereo DAC High End
• Manufacturer: Wolfson Microelectronics

Specifications of WM8740SEDS/V

• Resolution: 24 bit
• Operating Supply Voltage: 5 V
• Operating Temperature Range: - 40 C to + 85 C
• Mounting Style: SMD/SMT
• Number Of Dac Outputs: 4
• Number Of Dacs: 2
• Snr: 116 dB
• Supply Current: 19 mA
• Thd Plus Noise: - 104 dB
• Package / Case: SSOP-28
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

WM8740
MUTE MODES
Figure 11 Mute Modes
w
MUTEB
ZERO
SOFTMUTE
Automute:
Detect 1024
zero input
samples
The device has various mute modes.
Table 20 Mute Modes
•
1.
2.
3.
Reg bit OPE = ‘1’
MUTEB pin
AUTOMUTE
(detect 1024 zero
input samples)
Reg bit MUT
Gain = 00
(left and right)
RAM initialise
Loss of system
clock
No LRCLK or invalid
SCLK/LRCLK ratio
RB
Power-on reset
ANMUTE is an analogue muting signal gating the analogue signal at the output (after
the SC filter)
AUTOMUTE is asserted when both the IZD register bit is asserted and the input audio
data has been zero on both left and right channels for 1024 input samples. The first
non-zero sample de-asserts.
Applying a logic low to MUTEB or setting MUT in Reg2 causes the gain registers to
ramp to zero. When a logic high is applied, the gain ramps slowly back up to the value
held in the appropriate attenuation register (AL or AR). The ramp rate = 128/fs s/0.5dB
step.
ANRES is the reset to the switched capacitor filter.
GAINR[0:7]
GAINL[0:7]
IZD
DIGITAL FILTER
Unaffected
Gain ramped to zero
On release volume ramps
to previous value
Automute has no effect on digital
filters
As MUTEB pin
Gain = -∞dB
Gain initialised to 0dB
Not running (no clock). On clock
restart, filters initialised, RAM
initialised. Registers unchanged
Filters initialised, RAM initialised.
Registers unchanged
Reset – gain initialised to 0dB
Reset
GAINR are overridden to 00
MUTEB=0 then GAINL and
If SOFTMUTE is set or
gain ramps between
previous and new gain
setting
FREQ_INVALID
OPE
INIT
ANRES
Asserted
Asserted
Asserted
Asserted
Signal
Processing
ANALOGUE
PD, Rev 4.4, April 2010
ANMUTE
Asserted
Asserted when
gain = 0
Asserted after
1024 zero input
samples if IZD = 1
As MUTEB pin
Asserted
Asserted
Asserted
Asserted
Asserted
Asserted
Production Data
ANMUTE
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