AK2305 Datasheet, PDF (15/43 Pages) Asahi Kasei Microsystems – Dual PCM CODEC for ISDN TERMINAL ADAPTER

ASAHI KASEI
[AK2305]
POWER DOWN
Power consumption is reduced in power down mode.
In the power down mode, supply of current for analog circuits and clock for digital circuits, is stopped, and
relating circuits are halted.
There are two power down modes.
- Power down for all circuits
- Power down by block
* In the power down mode, output pins of corresponded blocks turn to Hi-Z.(See page 4)
POWER DOWN MODE SETTING
Mode
All circuits
Circuits Pin/Registers
Operation for
“0”/”1”
All
PD
”0” : Normal
”1” : Power down
Note
- Registers are not reset.
- Serial I/F is available.
- No need to supply FSn(n=0,1),BCLK.
CODEC
CH0
PDCH0
Block
CODEC
CH1
DTMF
Receiver0
PDCH1
PDDT0
”0” : Normal
”1” : Power down
DTMF
Receiver1
PDDT1
Note) Initial value of PDCHn, PDDTn(n=0,1) are “0”.
- Keep supplying first FS, even when
CODEC CH0,1 are in power down mode
(see page8).
- Even when CODEC CHn(n=0,1) is in
power down mode, the functions below are
available:
(1) AMPTn(n=0,1) Input/Output
(2) TONEGEN0,1 Output
From VRXn(n=0,1), TNOUT
- Even when all these blocks are in power
down mode; AMPT0/1, VR0/1R, AMPR0/1,
VRTN, TONEGEN0/1, BGREF, Serial IF,
PLL operate normally at all the time.
CANCELLATION OF POWER DOWN : CODEC
When power down mode for CODEC CH0/CH1 is cancelled, CODEC starts to be initialized.
It takes 130mS(typ.).
C0029-E-02
15
1999/8