THS7315_14 Datasheet, PDF (7/28 Pages) Texas Instruments – 3-Channel SDTV Video Amplifier with 5th-Order Filters and 5.2-V/V Gain

THS7315
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APPLICATION INFORMATION
SLOS532 – JUNE 2007
The THS7315 is targeted for standard definition (SD) video output buffer applications. Although it can be used
for numerous other applications, the needs and requirements of the video signal are the most important design
parameters of the THS7315. Built on the revolutionary complementary silicon-germanium (SiGe) BiCom3
process, the THS7315 incorporates many features not typically found in integrated video parts while consuming
very low power.
The THS7315 has the following features:
• Single-supply 3-V to 5-V operation with low total quiescent current of 15.6 mA at 3.3 V and 16.5 mA at 5 V.
• Input configuration accepting dc + level-shift, ac sync-tip clamp, or ac bias selection; ac-biasing is
accomplished with the use of an external pull-up resistor to the positive power supply.
• 5th-order low-pass filter for DAC reconstruction or ADC image rejection:
– 8.5-MHz for NTSC, PAL, SECAM, Composite (CVBS), S-Video Y'C', 480i/576i Y'P'_BP'_R , and G'B'R'
(R'G'B') signals.
• Internal fixed gain of 5.2 V/V (+14.3 dB) buffer that can drive up to two video lines per channel with dc
coupling or traditional ac coupling.
• Signal flow-through configuration using an 8-pin SOIC package that complies with the latest lead-free (RoHS
compatible) and green manufacturing requirements.
OPERATING VOLTAGE
The THS7315 is designed to operate from 3 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. The design of the THS7315 allows operation down to
2.85 V, but for best results, the use of a 3 V or greater supply should be used to ensure there are no issues with
headroom or clipping.
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 THS7315 outputs ringing or oscillating. Additionally, a large capacitor, such as 22 μF to
100 μF, should be placed on the power-supply line to minimize interference with 50-Hz/60-Hz line frequencies.
INPUT VOLTAGE
The THS7315 input range allows for an input signal range from –0.3 V to approximately (V_S+ – 1.5V). However,
because of the internal fixed gain of 5.2 V/V (+14.3 dB) and the internal level shift that shifts the output by
230 mV, 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 –0.3 V to +3.5 V. As a result of the gain and level shift, the linear output
range limits the allowable linear input range from about –0.1 V to +2.3 V.
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