STMicroelectronics has introduced two new 300 MHz amplifiers designed to drive very high-definition signals on 75-Ohm video lines in high-end industrial and medical imaging systems, and in HDTV-enabled set-top boxes and DVD players. The cost-effective TSH340 and TSH341 video amplifiers feature operation on a single 3 V to 5 V single power supply, with the capability to drive the video signal close to zero volts.

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The TSH340 is a buffer with internal gain, providing savings both on board space and in the number of components. Its gain is set at 6 dB to allow the right level of video signal while maintaining good line matching. The TSH341 is an op-amp that uses the same voltage feedback architecture as the TSH340, but allows the gain to be set externally. Both use a very high-speed 0.25-micron complementary manufacturing technology to achieve up to 300 MHz bandwidth for only 9.8 mA quiescent current.

High slew rates, low distortion and a gain flatness of 65 MHz, combined with a low input-voltage noise of 7 nV/sqrtHz, make the TSH340 and TSH341 devices suitable choices to drive DAC outputs on 75-Ohm video lines. The amplifiers feature input/output negative rail, which allows them to drive the signal to within 60 mV of ground--guaranteed by production testing--while operating on a single 5 V supply, and enables the video signal to be driven directly from the DAC output without any transition capacitance.

The amplifiers are specified for both 150-Ohm and 100-Ohm loads and are supplied in the tiny SOT23-5 and SO8 plastic packages. Both the video amplifiers are supported by an evaluation board kit, optimized for high-speed operational amplifiers, which includes a CD-ROM containing data sheets, application notes, articles and a user manual. They are available in volume now at a price of $1.50 for quantities of 5000.