ADL5303

Data Sheet FEATURES Optimized for fiber optic photodiode interfacing 8 full decades of range Law conformance: 0.1 dB from 1 nA to 1 mA Single-supply operation: 3.0 V to 5.5 V Complete and temperature stable Accurate laser trimmed scaling Logarithmic slope of 10 mV/dB (at the VLOG pin) Basic logarithmic intercept at 100 pA Easy adjustment of slope and intercept Output bandwidth of 10 MHz, 15 V/µs slew rate Miniature 16-lead package (LFCSP) Low power: ~4.5 mA quiescent current (enabled) APPLICATIONS High accuracy optical power measurement Wide range baseband log compression Versatile detector for APC loops GENERAL DESCRIPTION The ADL5303 is a monolithic logarithmic detector optimized for the measurement of low frequency signal power in fiber optic systems and offers a large dynamic range in a versatile and easily used form. Wide measurement range and accuracy are achieved using proprietary design and precise laser trimming. The ADL5303 requires only a single positive supply, VPS, of 5 V. When using low supply voltages, the log slope can be altered to fit the available span. Low quiescent current and chip disable facilitate use in battery-operated applications. The input current, IPD, flows in the collector of an optimally scaled NPN transistor, connected in a feedback path around a low offset JFET amplifier. The current summing input node operates at a constant voltage, independent of current, with a default value of 0.5 V; this may be adjusted over a wide range. An adaptive bi...