AK8815 Datasheet, PDF (16/37 Pages) Asahi Kasei Microsystems – NTSC/PAL Digital Video Encoder

ASAHI KASEI
[AK8815/16]
( 9 ) Color Burst Signal
Burst signal is generated by a 32 bit digital frequency synthesizer.
Color Burst Frequency is selected by mode setting of NTSC / PAL.
Standerd
NTSC-M
PAL-B,D,G,H,I
Subcarrier Freq
(MHz)
3.57954545
4.43361875
Burst Signal Table
Video Process 1
VMOD-bit
0
1
( 10 ) Video DAC
The AK8815/16 has a 9 Bit resolution, current-drive DAC as a video DAC which runs at 29.5 / 24.5454 MHz clock
frequency.
This DAC is designed to output 1.28 V o-p at full scale under the following conditions –
loading resistance of 390 ohms, VREF at 1.23 V and IREF pin resistor of 12 Kohms.
Here IREF pin resistor means a resistor connected between [ IREF ] pin and ground. DAC output voltage can be
adjusted by adjusting IREF pin resistor.
[ VREF ] pin should be connected to ground via a 0.1 uF or larger capacitor.
DAC output can be turned “ON” or “OFF” by register setting and current consumption can be lowered.
When the output is turned off, it is put into high impedance condition.
On-chip VREF circuit is kept active and only the DAC output is turned off then.
MS0331-E-00
16
2004 / 08