Trench process boosts amplifier performance

National Semiconductor has three new LMH amplifier products for the high-speed analogue market fabricated using its industry-leading VIP10 manufacturing process.

National Semiconductor has three new LMH amplifier products for the high-speed analogue market fabricated using its industry-leading VIP10 manufacturing process.

These products have improved AC performance, low noise, low power and large signal bandwidth for high-speed applications in video cameras, xDSL modems and set-top boxes.

The LMH6628, voltage feedback amplifier is an improved, lower power version of the CLC428.

It is the lowest-noise, 300MHz, 550V/us slew rate, dual amplifier on the market.

Its 2nV/(rt)Hz input voltage noise density makes it ideal for receiving small signals over long, twisted pair telephone lines such as VDSL applications.

The fast settling time of 12ns to 0.1% and low THD of -65dBc make it a good fit for 10bit data acquisition systems.

The ability to drive heavy capacitive loads also makes the LMH6628 suitable for directly driving analogue-to-digital convertors.

This allows the elimination of an additional buffer stage in the front end of many receiver applications.

The LMH6715 current feedback dual video amplifier is a faster version of the CLC412.

It has excellent key video specifications with differential gain and phase (DG/DP) of only 0.02 % /0.02deg.

The LMH6715's large signal, 3dB bandwidth of 170MHz at +2 gain for a 4V peak-peak output and 0.1dB gain flatness to 100MHz make it well suited for high-end video systems.

It is able to drive 8V peak-peak from a 10V supply, an improvement over the CLC412's output dynamic range by over 1V.

The improved AC parameters make the LMH6715 a good fit for many high-end consumer video applications such as video distribution systems, video cameras, video cable driving, multimedia systems and HDTV.

The LMH6718 dual programmable gain buffer (PGB) is an enhanced version of the CLC5632.

It has an improved output stage and can deliver 50% more current (200mA) than the CLC5632 while consuming less quiescent power (2.6mA per channel).

The LMH6718 PGB incorporates the normally external Rf/Rg resistors on die, allowing it to easily be programmed to a gain of -1, +1, +2 without external components.

This feature lowers parts count and reduces layout area, but also shields sensitive input noise nodes that are typically exposed on the board.

The output stage of the LMH6718 allows it to drive high capacitive, low resistive loads with minimum distortion while maximising output voltage swing.

The LMH6718 provides 110MHz bandwidth (Av=+2V/V) and 400V/us slew rates on a single +5V supply and 130MHz, 600V/us on dual +/-5V supplies.

Specific applications for the LMH6718 are dual, single-ended applications such as video line driving through coaxial cable and signal-boosting applications such as driving single-ended transformers for twisted pair.

Developed in National's wafer fabrication site in Arlington, Texas, VIP10 is a high-speed dielectrically isolated, complementary bipolar IC process that uses deep trench technology on a bonded wafer for complete dielectric isolation and optimal high-speed amplifier performance.

Trench technology with bonded wafers helps minimise parasitic capacitance for optimal power-to-bandwidth performance, lower distortion and decreased die size.

VIP10 is the process technology that allows National to design the most power-efficient, performance-oriented high-speed amplifiers on the market today.

National's LMH6628, LMH6715 and LMH6718 were all developed using the VIP10 process and are the first replacement parts for the CLC amplifiers portfolio.

Migration of other key CLC replacements will continue over the next year and be completed by June 2003.

The LMH6628 is available now in 8-pin SOIC packaging, and is priced at $1.98.

The LMH6715 is available in 8-pin SOIC packaging, and is priced at $1.69.

The LMH6718 is available in 8-pin SOIC packaging and is priced at $1.88.

All three prices are for 1000-unit quantities.

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