WM8985_07 WOLFSON [Wolfson Microelectronics plc], WM8985_07 Datasheet - Page 26

• Manufacturer Part Number: WM8985_07
• Description: Multimedia CODEC With Class D Headphone and Line Out
• Manufacturer: WOLFSON [Wolfson Microelectronics plc]

WM8985
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Table 4 Typical POR Operation (Typical Simulated Values)
1.
2.
3.
4.
5.
6.
DAC Group Delay
Notes:
t
t
t
t
hp__midrail_off
line_midrail_on
line_midrail_off
hp_midrail_on
SYMBOL
The lineout charge time, t
dependent upon the value of VMID decoupling capacitor and VMID pin input resistance and
AVDD1 power supply rise time. The values above were measured using a 4.7µF capacitor.
It is not advisable to allow DACDAT data input during initialisation of the DAC. If the DAC data
value is not zero at point of initialisation, then this is likely to cause a pop noise on the analogue
outputs. The same is also true if the DACDAT is removed at a non-zero value, and no mute
function has been applied to the signal beforehand.
The lineout discharge time, t
is dependent upon the value of VMID decoupling capacitor and VMID pin input resistance. The
values above were measured using a 4.7µF capacitor.
The headphone charge time, t
capacitor and VMID pin input resistance and AVDD1 power supply rise time. The values above
were measured using a 4.7µF VMID decoupling capacitor.
The headphone discharge time, t
capacitor and VMID pin input resistance. The values above were measured using a 4.7µF VMID
decoupling capacitor.
The VMIDSEL and BIASEN bits must be set to enable analogue output midrail voltage and for
normal DAC operation.
t
dacint
MIN
TYPICAL
29/fs
line_midrail_on,
300
300
2/fs
>6
>6
line_midrail_off,
hp_midrail_on,
hp_midrail_off,
MAX
is determined by the VMID pin charge time. This time is
is determined by the VMID pin discharge time. This time
is dependent upon the value of VMID decoupling
is dependent upon the value of VMID decoupling
UNIT
n/fs
n/fs
ms
ms
s
s
PP, Rev 3.5, March 2007
Pre-Production
26