TSH345IDT View Datasheet(PDF) - STMicroelectronics

Part Name

Description

Manufacturer

TSH345IDT

Triple video buffer with selectable filter for HD and SD video applications

STMicroelectronics 

Using the TSH345 to drive YC, CVBS, YUV, YPbPr and RGB video components

Figure 33. Flexibility of the TSH345 for SD and HD signals

HD/PV/SD

Y,G

DAC

150Ω

Pb,B,C

DAC

150Ω

Pr,R,CVBS

DAC

150Ω

+5V

75Ω

NC

75Ω

NC

TSH345

TSSOP14 75Ω

NC

SO14

Cable

75Ω

Cable

75Ω

Cable

75Ω

TV

TSH345

MUX and Filter select

(as defined in Table 4

and Table 5)

HD/PV/SD

Y,G

DAC

150Ω

Pb,B,C

DAC

150Ω

Pr,R,CVBS

DAC

150Ω

+5V

75Ω

NC

75Ω

NC TSH345

TSSOP14 75Ω

NC

SO14

SCART

RCA

R-G-B

Y-Pb-Pr

Y-C-CVBS

RCA

Y-C

CVBS

Cable

75Ω

Cable

75Ω

Cable

75Ω

TV

MUX and Filter select

(as defined in Table 4

and Table 5)

16/23

The TSH345 is used to drive either high-definition video signals up to 30 MHz or progressive

and interlaced standard definition video signals on 75-Ω video lines. It can drive a large

panel of signals such as YC and CVBS, YUV, YPbPr and RGB, where the bottom of the

signal (the synchronization tip in the case of Y and CVBS signals) is close to zero volts. An

internal input DC value is added to the video signal in order to shift the bottom from GND.

The shift is not based on the average of the signal, but is an analog summation of a DC

component to the video signal. Therefore, no input capacitors are required, which provides a

real advantage in terms of cost and board space.

Under these conditions, it is possible to drive the signal in single supply without any

saturation of the driver against the lower rail.

Since half of the signal is lost through output impedance matching, in order to properly drive

the video line the shifted signal is multiplied by a gain of 2 or +6 dB.

Share Link: