TSH344 Просмотр технического описания (PDF) - STMicroelectronics

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производитель

TSH344

340MHz single-supply triple video buffer

STMicroelectronics 

TSH344

Application information

Figure 27. Details on one channel of the TSH344

DAC

External resistor.

Load required by

the DAC output

specification

+5V

1/3 TSH344

(gain=2)

10nF

+

100µF

75Ω

STB

TV

470nH

video line

68pF

68pF

75Ω

0V

5Volt

1V

300mV

0Volt

5Volt

2V

600mV

0Volt

Low output Rail :

60mV max. tested

(see datasheet p.3: Vol)

1V

300mV

0Volt

Because of the shape of the signal described in Figure 25, we use a very low output rail

triple high-speed buffer. The TSH344 supplied in 5V single power supply features a low

output rail of 60mV (guaranteed by test) on 150Ω load. It is dedicated for driving RGB

signals without synchronisation (in the case where the synchronization is provided digitally

on the digital bus).

The gain of the TSH344 (gain=2) is internal which makes it possible to remove two resistors

on the BOM. To avoid any perturbation on matching from the DACs output impedance along

a large band of 30MHz in HD, a discrete reconstruction filtering is implemented after the

driver. This filter is matched on 75Ω. Note that the TSH344 uses a single supply architecture

and it is not AC output coupled (it cannot sink an output current, therefore it is not possible to

implement an output series capacitor).

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