Texas Instruments PCM5122 Evaluation Module PCM5122EVM-U PCM5122EVM-U Datenbogen
Produktcode
PCM5122EVM-U
XSMT
0.9 * DV
DD
t
r
t
f
<20ns
<20ns
0.1 * DV
DD
SLAS759A – AUGUST 2012 – REVISED SEPTEMBER 2012
Power Save Parameter Programming
Register
Description
Page 0, Register 2, D(4)
Software standby mode command
Page 0, Register 2, D(0)
Software power-down command
Software power-up sequence command (required after software standby or power-
Page 0, Register 2, D(4) and D(0)
down)
Page 0, Register 44, D(2:0)
Detection time of BCK and LRCK halt
XSMT Pin (Soft Mute / Soft Un-Mute)
For external digital control of the PCM514x, the XSMT pin needs to be driven by an external digital host with a
specific/minimum rising time (t
specific/minimum rising time (t
r
) and falling time (t
f
) for soft mute and soft un-mute. The PCM514x expects t
r
/t
f
times of less than 20ns. In the majority of applications, this shouldn’t be a problem, however, traces with high
capacitance may have issues.
capacitance may have issues.
When the XSMT pin is shifted from high to low (3.3V to 0V), a soft digital attenuation ramp is started. -1dB
attenuation will be applied every sample time from 0dBFS to -
attenuation will be applied every sample time from 0dBFS to -
∞
. The soft attenuation ramp takes 104 sample
times.
When the XSMT pin is shifted from low to high (0V to 3.3V), a soft digital “un-mute” is started. 1dB gain steps are
applied every sample time from -
applied every sample time from -
∞
to 0dBFS. The un-mute takes 104 sample times.
Figure 77. XSMT Timing for Soft Mute and Soft Un-Mute
Table 46. XSMT Timing Parameters
Parameters
Min
Max
Unit
Rise time (t
r
)
20
ns
Fall time (t
f
)
20
ns
Copyright © 2012, Texas Instruments Incorporated
65
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