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 TL441 is characterized for operation over 0°C to 70°C.