AK4703 Datasheet, PDF (13/38 Pages) Asahi Kasei Microsystems – AV SCART switch

ASAHI KASEI
AKM CONFIDENTIAL
[AK4703]
„ Full Power-down Mode
The AK4703 should be reset once by bringing PDN pin = “L” upon power-up.
PDN pin: Power down pin
L: Device power down.
H: Normal operation.
„ Auto Startup Mode
After when the PDN pin is set to “H”, the AK4703 is in the auto startup mode. In this mode, all blocks except for the video
detection circuit are powered down. Once the video detection circuit detects video signal from TVVIN pin or VCRVIN
pin, the AK4703 goes to the stand-by mode automatically and sends “H” pulse via INT pin. To exit the auto startup mode,
set the AUTO bit to “0”.
AUTO bit (00H D3): Auto startup bit
0: Auto startup disable. (Manual startup)
1: Auto startup enable. (Default)
„ AMP Power-down Mode
The internal AMP block can be powered-down by AMPPD bit. When AMPPD bit =”1”, the internal AMP block is
powered-down.
AMPPD bit (00H D2): AMP power-down bit
0: Normal operation.
1: AMP power-down. (Default)
„ Bias Mode
When the BIAS bit = “1”, the bias voltage on the audio output goes to GND level. Bringing BIAS bit to “0” changes this
bias voltage smoothly from GND to VP/2 by 2sec (typ.). This removes the huge click noise related the sudden change of
bias voltage at power-on. The change of BIAS bit from “1” to “0” also makes smooth transient from VP/2 to GND by 2sec
(typ). This removes the huge click noise related the sudden change of bias voltage at power-off.
BIAS bit (00H D1): Bias-off bit
0: Normal operation.
1: Set the audio bias to GND. (Default)
„ Standby Mode
When the AUTO bit = BIAS bit = “0” and the STBY bit = “1”, the AK4703 is forced into TV-VCR loop through mode.
In this mode, the sources of TVOUTL/R and MONOOUT pins are fixed to VCRINL/R pins; the sources of VCROUTL/R
are fixed to TVINL/R pins respectively. All register values themselves are NOT changed by STBY bit = “1”.
STBY bit (00H D0): Standby bit
0: Normal operation.
1: Standby mode. (Default)
„ Normal Operation Mode
To change analog switches, set the AUTO bit, BIAS bit and STBY bit to “0”. The AK4703 is in power-down mode until
PDN pin = “H”. The Figure 2 shows an example of the system timing at the power-down and power-up by PDN pin.
Rev. 0.1
- 13 -
2004/03