ADL5306

FEATURES Optimized for fiber optic photodiode interfacing Measures current over 3 decades Law conformance 0.1 dB from 100 nA to 100 μA Single- or dual-supply operation (3 V to ±5.5 V total) Full log-ratio capabilities Temperature stable Nominal slope of 10 mV/dB (200 mV/decade) Nominal intercept of 1 nA (set by external resistor) Optional adjustment of slope and intercept Rapid response time for a given current level Miniature 16-lead chip scale package (LFCSP 3 mm × 3 mm) Low power: ~5 mA quiescent current APPLICATIONS Low cost optical power measurement Wide range baseband logarithmic compression Measurement of current and voltage ratios Optical absorbance measurement GENERAL DESCRIPTION The ADL5306∗ is a low cost microminiature logarithmic converter optimized for determining optical power in fiber optic systems. The ADL5306 is derived from the AD8304 and AD8305 translinear logarithmic converters. This family of devices provides wide measurement dynamic range in a versatile and easy-to-use form. A single-supply voltage between 3 V and 5.5 V is adequate; dual supplies may optionally be used. Low quiescent current (5 mA typical) permits use in battery-operated applications. IPD, the 100 nA to 100 µA input current applied to the INPT pin, is the collector current of an optimally scaled NPN transistor that converts this current to a voltage (VBE) with a precise logarithmic relationship. A second converter is used to handle the reference current, IREF, applied to IREF. These inpu...