AK4250 Datasheet, PDF (5/8 Pages) Asahi Kasei Microsystems – Output Coupling Capacitor-less Video Amp with LPF

ASAHI KASEI
[AK4250]
■ Video Block
The Video Amp has a drivability for a load resistance of 150Ω. The AK4250 has a composite input and output and
includes a low pass filter (LPF). Internal negative power supply circuit supplies negative voltage to the video amp and
video amp 0V output is used for a pedestal level. Therefore, the output coupling capacitor can be removed.
AK4250
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
75Ω
VOUT
75Ω
0V
Figure 4. Video signal output
■ Power Down Control
When the PDN pin is “L”, the AK4250 is forced to the Power Down Mode (Power consumption: typ 1μA). VOUT pin
becomes Hi-Z at PDN pin = “L”. The AK4250 includes a power-on-reset function. Therefore any reset isn’t required
externally.
MS0540-E-00
-5-
2007/03