ETC 759P

Economy, Wideband
Log/Antilog Amplifiers
Models 759N, 759P
Low-Cost, Complete Log/Antilog Amplifier
External Components Not Required;
Internal Reference; Temperature Compensated
Small Size: 1.1" x 1.1" x 0.4"
Fast Response: 200kHz Bandwidth (ISIG @ 1µA)
6 Decades Current Operation - 1nA to 1mA
1% max Error - 20nA to 200µA
2% max Error - 10nA to 1mA
4 Decades Voltages Operation - 1 mV to 10V
1% max Error - 1mV to 2V
2% max Error - 1mV to 10V
Log Current or Voltage
Antilog Voltage
Data Compression or Expansion
Models 759N and 759P are low cost, fast response, dc logarithmic
amplifiers offering 1% conformance to ideal log operation over four
decades of current operation - 20nA to 200µA, as well as 2%
conformance over four decades of voltage operation - 1mV to 10V.
Featuring 200kHz bandwidth at ISIG = 1µA, these new economy designs
are the industry’s fastest log/antilog amplifiers and offer an attractive
alternative to in-house designs.
measurements, data compression and expansion, chemical analysis of
liquids, computing powers, roots and ratios and conversion of
exponential quantities to linear form.
Designed for ease of use, models 759N/P are complete, temperature
compensated, log or antilog amplifiers packaged in a small 1.1" x 1.1" x
0.4" epoxy encapsulated module. External components are not required
for logging currents over the complete six decade operating range from
1nA to 1mA. Both the scale factor (K = 2, 1, 2/3 volt/decade) and
log/antilog operation can be selected by simple pin interconnection. In
addition both the internal 10µA reference current as well as the offset
voltage may be externally adjusted to improve overall accuracy
Model 759N computes the log of positive input signals (voltage or
current), while model 759P computes the log of negative input signals
(voltage or current). In the antilog mode of operation, both models
accept bipolar voltage input signals (-2V≤ESIG/ K≤-2V), with model
759N producing a positive output signal and model 759P producing a
negative output signal.
Model 759N and 759P can operate with either current or voltage
inputs when connected as shown in Figure 1. To illustrate the
logarithmic transfer characteristics, a plot of input current versus
output voltage is also presented. Model 759 is ideally suited for
log applications whenever low cost implementation of
logarithmic natural relationships is advantages. Examples are
Information furnished by Intronics is believed to be accurate and reliable. However, no
responsibility is assumed by Intronics for its use; nor for any infringements of patents or
other rights of third parties which may result from its use. No license is granted by
implication or otherwise under any patent or patent rights of Intronics.
Figure1. Functional Block Diagram and Transfer Function
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