Monolithic DC-to-120-MHz Log-amp is Stable and Accurate

AD640 Provides Total Calibration over Wide Temperature Ranges; Can Be Paired for up to 95-dB Dynamic Range

by Barrie Gilbert and Bob Clarke Download PDF

The AD640 is a monolithic laser-trimmed multi-stage logarithmic amplifier ("log amp")–a complete, calibrated measurement system comprising five 10-dB stages with paralleled current outputs that produce a device output precisely proportional to the logarithm of the input voltage. Deviating only ±0.6 dB from the ideal function, the AD640 is designed from the outset to exhibit high stability with temperature through the use of accurate nonlinear-circuit design principles. Read full article

Authors

Barrie Gilbert

Barrie Gilbert, the first ADI Fellow, has “spent a lifetime in the pursuit of analog elegance.” He joined Analog Devices in 1972, was appointed ADI Fellow in 1979, and manages the Northwest Labs in Beaverton, Oregon. Barrie was born in Bournemouth, England, in 1937. Before joining ADI, he worked with first-generation transistors at SRDE in 1954, and at Mullard, Ltd.; later at Tektronix and Plessey Research Labs. Barrie is an IEEE Fellow (1984) and has received numerous awards. He has some 50 issued patents, has authored about 40 papers, is coauthor of several books, and is a reviewer for several journals. He was awarded an Honorary Doctorate of Engineering from Oregon State University in 1997.

Bob Clarke