WM8986_07 WOLFSON [Wolfson Microelectronics plc], WM8986_07 Datasheet - Page 21

• Manufacturer Part Number: WM8986_07
• Description: Multimedia DAC With Class D Headphone and Line Out
• Manufacturer: WOLFSON [Wolfson Microelectronics plc]

Pre-Production
Figure 10 DAC Power Up and Down Sequence (not to scale)
w
Table 3 Typical POR Operation (Typical Simulated Values)
Notes:
DAC Group Delay
1.
2.
3.
4.
5.
6.
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
time 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
51/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
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 3.1, February 2007
WM8986
21