LMH1251 Datasheet | National Semiconductor

Description The LMH™1251 is a wideband 2:1 analog video switch with an integrated YPBPR to RGB decoder. The device accepts one set of YPBPR inputs and one set of RGB/HSYNC/ VSYNC inputs. Based on the input selected, the output will be either a decoded TV or buffered PC video signal. The LMH1251 has a SYNC separator and processor that is capable of extracting sync timing information from both Standard Definition Television (SDTV) and High Definition Television (HDTV) inputs. It provides bi-level sync, and tri-level sync separation. The color space conversion from YPBPR to RGB in the LMH1251 is realized with a very high precision fully analog dematrixer that provides chrominance accuracy that is less than 2.5% of amplitude & 1.5˚ of phase error on a vectorscope. It is equipped with a smart video detection circuit which automatically senses SDTV and HDTV video formats and applies the appropriate color space conversion. The LMH1251 is capable of handling SDTV, HDTV, XGA, SXGA, and UXGA video formats, which makes it an ideal solution for enhancing value in applications ranging from LCD monitors, to set-top boxes, to projectors. The LMH1251 is available in a TSSOP-24 package. Features YPBPR to RGB decoding YPBPR path: 70 MHz, - 3 d B, 700 m VPP bandwidth RGB path: 400 MHz, - 3 d B, 700 m VPP bandwidth Supports PC video display resolutions up to UXGA (1600 x 1200 @ 75 Hz) n Supports 480i, 480p, 576i, 576p, 720p, 1080i, and 1080p n Smart video format detection for SD and HD n Power save mode n n n n Applications n n n n TFT LCD monitor CRT monitor Set-top box Display projector Connection Diagram 24-Pin TSSOP Top View LMH™ is a trademark of National Semiconductor Corporation. © 2005 National Semiconductor Corporation DS201519 .national. Truth Table TABLE 1. Input Select Pin 24 0 1 OUT RGBhv input Ch YPBPR input Ch TABLE 2. Pin 23 0 0 1 1 Pin 22 0 1 - Outputs 0 - Outputs 1 SYNC Bi-Level Tri-Level Bi-Level Tri-Level Format Detection Manual Manual Auto...