ASAHI KASEI
[AK4250/52]
Video Block
The Video Amp has a drivability for a load resistance of 150Ω. The AK4250/52 have a composite input and output and
includes a low pass filter (LPF). Internal negative power supply circuit supplies the negative voltage to the video amp and the
video amp 0V output is used for a pedestal level. Therefore, the output coupling capacitor can be removed.
AK4250/52
VDD
Charge
Pump
Negative Power
CP
CN
VSS
VEE
C2
(+)
1uF
(+)
1uF
C1
Note 6. C1 and C2 capacitors should have the low ESR (Equivalent Series Resistance) over all temperature range.
When these capacitors have the polarity, the positive polarity pin should be connected to the CP pin and the
VSS pin. Non polarity capacitors can also be used.
Figure 3. Negative Power Supply circuit
AK4250/52
75Ω
VOUT
75Ω
0V
Figure 4. Video signal output
Power Down Control
When the PDN pin is “L”, the AK4250/52 are forced to the Power Down Mode (Power consumption: typ 1μA). VOUT pin
becomes Hi-Z at PDN pin = “L”. The AK4250/52 include a power-on-reset function. Therefore any reset isn’t required
externally.
Rev.0.4
2006/11
- 5 -
AKM [ ASAHI KASEI MICROSYSTEMS ]
