Controlled Baseline
− One Assembly/Test Site, One Fabrication
Site
Extended Temperature Performance of
−55°C to 125°C
Enhanced Diminishing Manufacturing
Sources (DMS) Support
Enhanced Product-Change Notification
Qualification Pedigree†
Excellent Dynamic Range
Wide Bandwidth
Built-In Temperature Compensation
Log Linearity (30-dB Sections) . . . 1 dB Typ
Wide Input Voltage Range

DESCRIPTION
This amplifier circuit contains four 30-dB logarithmic stages. Gain in each stage is such that the output of each
stage is proportional to the logarithm of the input voltage over the 30-dB input voltage range. Each half of the
circuit contains two of these 30-dB stages summed together in one differential output that is proportional to the
sum of the logarithms of the input voltages of the two stages. The four stages may be interconnected to obtain
a theoretical input voltage range of 120-dB. In practice, this permits the input voltage range typically to be greater
than 80-dB with log linearity of ±0.5-dB (see application data). Bandwidth is from dc to 40 MHz.
This circuit is useful in data compression and analog compensation. This logarithmic amplifier is used in log IF
circuitry as well as video and log amplifiers.
The TL441M is characterized for operation over the full military temperature range of −55°C to 125°C.