Linear Technology introduces the LTC1414, 14-bit analog-to-digital converter (ADC) with both 2.2Msps sampling and the high dynamic performance necessary in high-speed DSL modem applications. The LTC1414 has 80dB signal-to-noise and distortion (SINAD) and 95dB spurious free dynamic range (SFDR), with no significant degradation of conversion performance even at the Nyquist input frequency of 1.1MHz. This performance lets telecommunications equipment transmit cleaner signals over greater distances compared to designs based on pipelined ADCs or integrated analog front ends. The LTC1414's high speed parallel interface and bipolar ý2.5V input range make it well suited for these applications, particularly the more demanding central office modems.

The LTC1414 includes a 40MHz bandwidth sample-and-hold with outstanding AC performance beyond the Nyquist input frequency of 1.1MHz. Operating on ý5V supplies with a differential input and an internal reference, it allows direct coupling to most high performance op amps thus eliminating special translation circuitry.

Signal processing and high speed data acquisition applications will also benefit from the LTC1414's low power dissipation and small size. Its narrow 28-lead SSOP package enables compact designs without the complications that wider packages with longer traces typically involve.

This is clearly not a commodity part in any shape or form -- or price -- and is very much pitched at the central office, not the residential, modem. The SINAD and SFDR above are quoted for 100 kHz, and that might be valid from an applications standpoint, but it would be fairer when comparing with competitive products to probably look at the Nyquist input frequency (1.1 MHz) numbers of 78 dB for SINAD and 86 dB for SFDR (and I think of 9 dB drop in SINAD as "significant." These are still excellent numbers and I am sure that the company must have already secured some design wins with the part. Overall I think that Linear is probably correct that central office modems are more likely to use this kind of technology, particularly avoiding pipeline delay which by itself could limit transmission speeds on a bi-directional basis.

I love the full 40-MHz bandwidth sampling and the 175 mW dissipation. As noted the LTC1414 is in a 28-lead SSOP and it is priced at $20.00 in 1000-piece lots.