Programmable Mic Preamp Improves Dynamic Range

Promising significant improvements in dynamic range and design flexibility to designers of pro audio equipment, the THAT1570/5171 microphone preamplifier chipset teams a differential audio preamplifier (1570) with a separate digital preamp controller (5171). Compared to single-chip offerings operating with ±5V supplies, the duo reportedly enables greater flexibility with up to 130 dB of dynamic range when operating from ±17 V supplies, allowing users to tradeoff power consumption versus dynamic range. Programmable across 56 1-dB steps from 13.6 dB to 68.6 dB, the chipset provides an additional gain setting of +5.6 dB that allows for line inputs up to +22 dBu. Other specs include a noise figure of 1.5 nV/vHz at 68.6 dB gain and 20 nV/vHz at 5.6 dB gain, THD+N of 0.0003% at 21.6 dB, and a bandwidth of 1.8MHz at 40.6 dB. Features that promise to simplify design chores include a servo for minimizing dc offset, zero crossing detector and other unique techniques for minimizing gain-switching noise, and four general-purpose digital outputs. The 1570 comes in a 4 mm x 4 mm QFN16 package and the 5171 in a 7 mm x 7 mm QFN32. Price for the chipset is less than $10 each/1,000 and a demo board is available for $250. THAT CORP., Milford, MA. (508) 478-9200.