LA7357 View Datasheet(PDF) - SANYO -> Panasonic

Part Name

Description

Manufacturer

LA7357

PAL/SECAM Discrimination Circuit for VHS VCRs

SANYO -> Panasonic 

Pin Functions

Pin No.

Pin

LA7357

Pin Functions

1

CHROMA-IN

• Chrominance signal input. This pin can handle burst (or unmodulated

carrier for SECAM input) signal amplitudes of between 50 and 800 mVp-p.

Equivalent circuit

• High-pass filter output monitor

2 HPF.MONI To avoid interference between pin 1 and pin 3, this pin should be

connected to VCC during normal operation.

• Phase comparator output

This signal is smoothed with an external capacitor.

3

FILTER The smoothed level will be:

2.0 V or lower for PAL

3.5 V or higher for SECAM or MESECAM.

4

GND

• BGP + SYNC input

The input level is a 1.0- to 2.0-V rising pulse ( ) during the SYNC period,

and a 3.0- to 4.5-V rising pulse ( ) during the BGP period. Note that since

5 SYNC+BGP a combined BGP and C.SYNC pulse ( ) is output from the Y/C IC when

the LA7357 is used in combination with a Sanyo single-chip Y/C IC (any

one of the LA7430, LA7435, or LA71520) no external component will be

required on pin 5.

• Discrimination sensitivity adjustment pin

6

DET-ADJ

The discrimination is shifted towards PAL as the pin voltage is increased,

and towards SECAM as the pin voltage is lowered.

This pin is normally left open.

7

VCC

Continued on next page.

No. 5654-4/6

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