AD830481601406MEAN + 31204100280HITSDRIFT – mV0OS60v–240MEAN – 3–420–60–40 –30 –20 –1001020304050607080906080100120140TEMPERATURE –CLOGARITHMIC INTERCEPT – pA TPC 19. Output Buffer Offset vs. Temperature TPC 21. Distribution of Logarithmic Intercept, (3σ to Either Side of Mean) Sample 1000 180180160160140140120120100100HITSHITS808060604040202000196198200202204–20–1001020LOGARITHMIC SLOPE – mV/decINPUT GUARD OFFSET – mV TPC 20. Distribution of Logarithmic Slope, Sample 1000 TPC 22. Distribution of Input Guard Offset Voltage (VINPT – VSUM), Sample 1000 REV. A –7– Document Outline FEATURES APPLICATIONS PRODUCT DESCRIPTION FUNCTIONAL BLOCK DIAGRAM SPECIFICATIONS ABSOLUTE MAXIMUM RATINGS PIN CONFIGURATION PIN FUNCTION DESCRIPTIONS ORDERING GUIDE Typical Performance Characteristics BASIC CONCEPTS Optical Measurements Decibel Scaling GENERAL STRUCTURE Bandwidth and Noise Considerations Chip Enable USING THE AD8304 Slope and Intercept Adjustments Low Supply Slope and Intercept Adjustment Using the Adaptive Bias Changing the Voltage at the Summing Node Implementing Low-Pass Filters Operation in Comparator Modes Using a Negative Supply APPLICATIONS Summing Node at Ground and Voltage Inputs Providing Negative Outputs and Rescaling Inverting the Slope Programmable Level Comparator with Hysteresis Programmable Multidecade Current Source Characterization Setups and Methods Evaluation Board OUTLINE DIMENSIONS Revision History