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Rainbow Electronics MAX9671 User Manual

Page 16

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MAX9670/MAX9671

Low-Power Audio/Video Switch with Audio
Volume Control for Dual SCART Connectors

16

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Video Section

The video circuit routes different video formats between
the set-top box decoder, the TV SCART connector, and

the VCR SCART connector. It also routes slow-switch
and fast-switch control information. See Figure 3.

MAX9670/MAX9671

A

V

= 2V/V

TV_Y/CVBS_IN

MUTE

TV_Y/CVBS_OUT

LOAD SENSE

A

V

= 2V/V

VCR_Y/CVBS_OUT

LOAD SENSE

CLAMP

VCR_Y/CVBS_IN

CLAMP

ENC_Y/CVBS_IN

CLAMP

ENC_Y_IN

CLAMP

ACTIVITY DETECT

ACTIVITY DETECT

ACTIVITY DETECT

ACTIVITY DETECT

LPF

LPF

A

V

= 2V/V

MUTE

TV_R/C_OUT

A

V

= 2V/V

VCR_R/C_OUT

VCR_R/C_IN

CLAMP/BIAS

ENC_R/C_IN

CLAMP/BIAS

ENC_C_IN

CLAMP/BIAS

LPF

LPF

A

V

= 2V/V

MUTE

TV_G_OUT

VCR_G_IN

CLAMP

ENC_G_IN

CLAMP

LPF

A

V

= 2V/V

MUTE

TV_B_OUT

VCR_B_IN

CLAMP

ENC_B_IN

CLAMP

LPF

A

V

= 1V/V

VCRIN_FS

0.7V

V

VID

GNDVID

TVOUT_FS

TO I

2

C

A

V

= 1V/V

V

12

+6V

EP

TV_SS

x1

TO I

2

C

A

V

= 1V/V

V

12

+6V

EP

VCR_SS

x1

Figure 3. MAX9670/MAX9671 Video Section Function Diagram