AK4201 Datasheet, PDF (10/13 Pages) Asahi Kasei Microsystems – Stereo Cap-less HP-Amp

CONFIDENTIAL
[AK4201]
■ Power-Up/Down Sequence
The PDN pin must keep “L” until all power supply pins (AVDD, PVDD) are supplied, and must be set to “H” after all
powers are supplied.
Power Supply
Former Device
DAC etc
Former Device
Click noise
(1)
Don’t Care
Power Up
(No Signal Output)
Ta
(2)
(4)
0V
A
PDN pin
PVEE pin
0V
(3)
Normal Operation
PVEE pin Output =-3.3V(Typ.)
Don’t Care
(5)
0V
HPL/HPR pins
0V
Normal Operation(0V Common)
0V
Figure 4. Power-up/down Sequence example
(1) The interval from power Up to PDN pin = “L” → “H”
“L” time of 150ns or more is needed to reset the AK4201.
The power should be ON in state of the PDN pin = “L”. The PDN pin should be set to “H” after power supply
(AVDD, PVDD) are ON.
(2) The interval from former device of the AK4201(DAC etc) power up to the PDN pin = “L” → “H”
The former device of the AK4201 should be powered up with no output (MUTE). When step wave which generated
by former device is output (an instant change of DC offset), HPF response wave will occur at “A” period of the
Figure 4, according to the AK4201 input coupling condenser (Ci) and input resistor (Ri). In order to avoid click
noise, “Ta” wait time is needed after former device output.
Ta calculation example: (in the case of Ci =0.22uF, Ri = 20kΩ)
τ=0.22u * 20k = 4.4ms
Ta =τ* 7.6 = 33ms
(When noise level by former device= 2V, response wave level= 1mV. 7.6*τ is needed)
If waiting time is not sufficient, click noise maybe occur, but no problem for later working.
(3) 50ms (max.) later, after the PDN pin went to “H”, the AK4201 will be in normal operation mode and click noise is
decreased. In this interval (50ms), the former device should be MUTE.
(4) The former device should starts outputting the signal after the AK4201 starts Normal Operation. If click noise is
generated by former device when MUTE is canceled, it will be output from the AK4201.
(5) The PDN pin = “L”. LOUT/ROUT pins short to VSS1 with 20Ω(typ.). After 50ms (max.), the PVEE pin will be 0V
according to a capacitor which connected to PVEE and internal resistance (typ. 17.5kΩ). The AK4201 can be
powered up again after 150ns or more from the PDN = “L”.
Rev 0.2
- 10 -
2008/07