Burr-Brown Corporation announced the INA2132, the industry's first dc-accurate low cost, dual difference amplifier designed specifically for industrial and instrumentation applications.

The difference amplifier is a simplified version of an instrumentation amplifier. Because it does not have input buffer amplifiers, it is inexpensive. Although its input resistance is lower, its high accuracy makes it ideal for many portable, battery-powered scientific and medical instrumentation, sensor and transducer signal conditioning, and industrial process control systems.

"The INA2132 provides a highly versatile circuit function without using an expensive precision resistor network. Consequently, the system designer using discrete circuits will be unable to achieve the same performance for less money," said John Brown, strategic marketing engineer at Burr-Brown. "In addition, two difference amplifiers in one small package makes it well suited for space-limited or multi-channel applications."

Key specifications of the industrial-specified INA2132 include low dc offset (75ıV) and temperature drift (1ıV/ıC), high CMRR (90dB), low gain error (ı0.01%) and temperature drift (1ppm/ıC), and close swing to supply rails. The INA2132 operates on a wide single supply range (5V to 36V) or dual supplies (ı1.35V to ı18V) at low quiescent current (160ıA per amp).

I was looking at a proposed new design for a monitoring system for a sleep disorder clinic just before this product's press release crossed my PC screen. Going back to that design -- which is highly complex and replaces 6 year old technology which is now wildly out of date -- I could see how this product could drop in perfectly with nary a basic change in the downstrean ADCs and processing. That single application represents 32 channels.

When you think about it there are simply dozens of sensor and instrumentation applications that don't need the buffer amplifiers provided in the conventional instrumentation amplifier package. So why pay for them? And if you are the typical analog designer who thinks it his role to design such circuits discretely why not look again at the performance numbers you would be ripping your hair out to get near: 160ıA quiescent current per channel, only 75ıV dc offset and a 90 dB coomon-mode rejection ratio!

I also like the really small gain error with this part and the ability to employ it across the board on supply rails up to the 30-V industrial uses. There is also a single channel part, the INA132. The INA2132 is in production in a SO-14 and is priced at $2.45 in 1000-piece lots.