Truth Table

TABLE 1. Input Select

Pin 24

OUT

0

RGBhv input Ch

1YP

TABLE 2.

Pin 23

Pin 22

SYNC

Format Detection

Decoding Scheme

0

0

Bi-Level

Manual

480p

0

1

Tri-Level

Manual

720p/180i

1

*Outputs 0

Bi-Level

Auto

480p

1

*Outputs 1

Tri-Level

Auto

720p/1080i

Note: * When Pin 23 is set high, the LMH1251 is in Auto Mode, in which it can

detect the incoming video format (SD or HD) and apply the appropriate

color decoding and sync processing. With Auto Mode, Pin 22 becomes

an output pin, and will either output a logic high or low to notify the user

of the format that is being detected by the LMH1251. If Pin 23 is set

low, the LMH1251 is in Manual Mode, in which the user must specify

the format with Pin 22. With Manual Mode, Pin 22 is an input pin. Since

Pin 22 is a bi-directional pin, care must be taken to not apply any

voltages to it when it is in the Auto Mode, in which it functions as an

output pin. The use of the Auto Mode with Pin 22 left floating is typically

recommended.

TABLE 3. Power Save

Pin 21

Low Power Mode

0

Disable

1

Enabled

Ordering Information

Package

Part Number

Package Marking

Transport Media

NSC Drawing

24-Pin TSSOP

LMH1251MT

LMH1251MT

61 Units/Rail

MTC24

LMH1251MTX

2.5k Units Tape and Reel

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