AD8305ACPZ-RL7

AD8305ACPZ-RL7 is an inexpensive microminiature logarithmic converter optimized for determining optical power in fibre optic systems. It uses an advanced implementation of a classic translinear (junction-based) technique to provide a large dynamic range in a versatile and easily used form. A single-supply voltage of between 3V and 12V is adequate; dual supplies may optionally be used. The low quiescent current (typically 5mA) permits use in battery-operated applications. The input current, IPD, of 10nA to 1mA applied to the INPT pin is the collector current of an optimally scaled NPN transistor, which converts this current to a voltage (VBE) with a precise logarithmic relationship. A second such converter is used to handle the reference current (IREF) applied to pin IREF. Applications include optical power measurement, wide-range baseband logarithmic compression, measurement of current and voltage ratios, and optical absorbance measurement.

• Optimized for fibre optic photodiode interfacing, measures current over 5 decades
• Full log-ratio capabilities, optional adjustment of slope and intercept
• Complete and temperature stable, rapid response time for a given current level
• Input offset voltage is 20mV maximum at (VINPT − VSUM, VIREF − VSUM)
• Small signal bandwidth is 0.7MHz typical at (IPD > 1µA)
• Wideband noise is 0.7mV√Hz typical at (IPD > 1µA)
• Quiescent current is 5.4mA typical at (VP = 5V, VN = 0V, TA = 25°C)
• Positive supply voltage range from 3V to 12V
• Operating temperature range from -40°C to +85°C
• 16-lead LFCSP package

Notes

ADI products are only authorized (and sold) for use by the customer and are not to be resold or otherwise passed on to any third party