7-GHz ADC drivers bring AC performance to DC-coupled applications

November 19, 2014 // By Graham Prophet
Texas Instruments has added two fully differential amplifiers (FDAs) that provide DC-coupled applications with best-in-class AC performance; the LMH3401 and LMH5401 FDAs provide higher bandwidth and slew rate, and lower distortion than existing ADC drivers.

The LMH3401 provides 16 dB of gain with higher performance than similar FDAs, while providing a 30% reduction in both size and power consumption. It delivers 7 GHz of -3-dB bandwidth at 16-dB gain, a slew rate of 18,000 V/µs, and harmonic distortion of -77 dBc at 500 MHz.

The LMH5401 can be configured for 6 dB of gain or more, delivering 6.2 GHz of -3 dB bandwidth at 12-dB gain. It has a slew rate of 17,500 V/µsec, harmonic distortion of -90 dBc at 200 MHz, and IMD3 of -90 dBc at 200 MHz.

Both the LMH3401 and LMH5401 deliver highest bandwidth and slew rate at low power; they also eliminate the need for baluns, converting a signal from single-ended to differential.

The LMH3401 and LMH5401 minimise data converter distortion from true DC to more than 1 GHz in receive and transmit applications. This enables system designers to optimise the performance of the company's highest-speed data converters, such as the 12-bit, 4-GSPS ADC12J4000; 16-bit, 370-MSPS ADC16DX370; and 16-bit, 2.5-GSPS DAC38J84.

Evaluation modules are available for both the LMH3401 and LMH5401 at a price of $149. TINA-TI SPICE models and reference designs are also available to simulate system performance.