AK4950 Datasheet, PDF (66/106 Pages) Asahi Kasei Microsystems – 24bit Stereo CODEC with MIC/SPK/Cap-less VIDEO-AMP & mini DSP

[AK4950]
■ Video Block
The integrated cap-less video amplifier with charge pump has drivability for a load resistance of 150Ω (Figure 49). The
AK4950 has a composite input and output. A Low Pass Filter (LPF) and Gain Control Amp are integrated, and VG1-0
bits set the gain (+6/+9/+12/16.5 dB) (Table 54). The video signals can be output as pedestal level 0V by supplying
negative power to the video amplifier from the charge pump circuit (Figure 50). Therefore AC-coupling capacitor is not
needed. And also, the external flying capacitor for charge pump is not needed because it is included. The video amplifier
power management is controlled by PMV bit. The charge pump circuit power management is controlled by PMCP bit.
When PMV bit = “0”, the VOUT pin outputs 0V. The video inputs must be AC-coupled by a 0.1μF capacitor. The video
signal source impedance at transmitting side must not over 600Ω.
VIN
max 600Ω
Typ 0.1µF
Clamp
PMV bit
LPF
+6/+9/+12/+16.5dB
VOUT
PMCP bit
Clock
Generator
Charge
Pump
VSS4
PVEE
2.2µF
Figure 49. Video Block Diagram
VG1-0 bits
GAIN
00
+6dB
(default)
01
+9dB
10
+12dB
11
+16.5dB
Table 54. Video Signal Gain Setting
MS1320-E-00
- 66 -
2011/10