Precision Transimpedance Logarithmic Amplifier with Over 5 Decades of Dynamic Range

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The MAX4206 logarithmic amplifier computes the log ratio of an input current relative to a reference current (externally or internally generated) and provides a corresponding voltage output with a default 0.25V/decade scale factor. The device operates from a single +2.7V to +11V supply or from dual ±2.7V to ±5.5V supplies and is capable of measuring five decades of input current across a 10nA to 1mA range.

The MAX4206's uncommitted op amp can be used for a variety of functions, including filtering noise, adding offset, and adding additional gain. A 0.5V reference is also included to generate an optional precision current reference using an external resistor, which adjusts the log intercept of the MAX4206. The output-offset voltage and the adjustable scale factor are also set using external resistors.

The MAX4206 is available in a space-saving 16-pin thin QFN package (4mm x 4mm x 0.8mm), and is specified for operation over the -40°C to +85°C extended temperature range.
MAX4206: Typical Operating Circuit MAX4206: Typical Operating Circuit Enlarge+

Key Features

  • Single Supply Capability Reduces System Power Supply Requirements
    • +2.7V to +11V Single-Supply Operation
    • Also Supports ±2.7V to ±5.5V Dual-Supply Operation if Required
  • Wide Dynamic Range Supports Most Photodiode Current Measurement Applications
    • 5 Decades of Dynamic Range (10nA to 1mA)
    • Monotonic Over a 1nA to 1mA Range
    • Adjustable Output Scale Factor
    • 0.25V/Decade Internally Trimmed Output Scale Factor
    • Adjustable Output Offset Voltage
    • Internal 10nA to 10µA Reference Current Source
    • 0.5V Input Common-Mode Voltage
  • Small Package and Few External Components Saves Space and Simplifies Design-In
    • 16-Pin TQFN Package (4mm x 4mm x0.8mm)


  • Analog Signal Processing
  • Medical Instrumentation
  • Photodiode Current Monitoring
  • Portable Instrumentation

See parametric specs for Logarithmic Amplifiers (2)

Part NumberVSUPPLY (Single)
VSUPPLY (Single)
Log. Slope
(mV/ decade)
Dynamic Range
Package/PinsOper. Temp.
minmaxminmaxtypSee Notes
MAX4206 2.7112.75.53.9250100
-40 to +85$3.77 @1k

See parametric specs for Transimpedance Amplifiers (TIA) (16)

Part NumberTarget Oper. Range
Data Rate
Input Noise
MAX4206 <10.00553.917000510
See Data Sheet

Pricing Notes:
This pricing is BUDGETARY, for comparing similar parts. Prices are in U.S. dollars and subject to change. Quantity pricing may vary substantially and international prices may differ due to local duties, taxes, fees, and exchange rates. For volume-specific and version-specific prices and delivery, please see the price and availability page or contact an authorized distributor.

MAX4206EVKIT: Evaluation Kit for the MAX4206

Technical Documents

App Note 3611 Integrated DC Logarithmic Amplifiers
Product Reliability Reports: MAX4206.pdf 
Device   Fab Process   Technology   Sample size   Rejects   FIT at 25°C   FIT at 55°C   Material Composition  

Note : The failure rates are summarized by technology and mapped to the associated material part numbers. The failure rates are highly dependent on the number of units tested.

Quality Management System >
Environmental Management System >


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