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APPLICATIONS INFORMATION

OPERATING VOLTAGE

INPUT VOLTAGE

THS7347

SLOS531 – MAY 2007

The THS7347 is targeted for RGB+HV video buffer applications. Although it can be used for numerous other

applications, the needs and requirements of the video signal were the most important design parameters of the

THS7347. Built on the revolutionary complementary silicon-germanium (SiGe) BiCom3 process, the THS7347

incorporates many features not typically found in integrated video parts while consuming very low power. Each

channel configuration is completely independent of the other channels. This architecture allows for any

configuration for each channel to be dictated by the end user, rather than the part dictating what the

configuration must be—resulting in a highly flexible system.

The THS7347 has the following features:

• Single-supply 2.7-V to 5-V operation with low quiescent current of 80 mA at 3.3 V.

• 2:1 input mux.

• Input configuration accepts dc, dc + shift, ac bias, or ac sync-tip clamp selection.

• 500-MHz unity-gain buffer amplifier to drive ADC/Scalar/Decoder.

• Monitor Pass-Through path has an internal fixed gain of 2 V/V (+6 dB) amplifier that can drive two video lines

per channel with dc coupling, traditional ac coupling, or SAG-corrected ac coupling.

• While disabled, the Monitor Pass-Through path has a very high output impedance (> 500 kΩ || 8 pF)

• Power-Up Control (PUC) allows the THS7347 to be fully disabled or have the Monitor Pass-Through function

(with ac-bias mode on all channels) enabled upon initial device power-up.

logic.

• H-Sync and V-Sync paths have an externally-adjustable Schmitt trigger threshold

• Disable mode reduces quiescent current to as low as 0.1-µA.

The THS7347 is designed to operate from 2.7 V to 5 V over a -40

°C to +85°C temperature range. The impact on

performance over the entire temperature range is negligible because of the implementation of thin film resistors

and high-quality, low temperature coefficient capacitors.

A 0.1-

µF to 0.01-µF capacitor should be placed as close as possible to the power-supply pins. Failure to do so

may result in the THS7347 outputs ringing or oscillating. Additionally, a large capacitor, such as 100

µF, should

be placed on the power-supply line to minimize issues with 50-Hz/60-Hz line frequencies.

because of the internal fixed gain of 2 V/V (+6 dB), the output is generally the limiting factor for the allowable

linear input range. For example, with a 5-V supply, the linear input range is from GND to 3.4 V. As a result of the

gain, the linear output range limits the allowable linear input range from GND to 2.5 V at most.

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