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LOG200

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High-speed precision logarithmic amplifier with photodiode bias and dark-current correction

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Data sheet

LOG200

ACTIVE
Data sheet Order now

Product details

Input current range (min) (nA) 0.1 Input current range (max) (mA) 10 Offset voltage (input amplifiers) (max) (mV) 2 Vs (±) (min) (V) 4.5 Vs (±) (max) (V) 12.6 Iq (max) (mA) 9 Dynamic range (typ) (dB) 160 Reference type Int Auxiliary op amps 1 Full-scale output voltage (min) (±V) 4.8 Full-scale output voltage (max) (±V) 12.3 Conformity error (initial 5 decades) (max) (%) 1.5 Conformity error (initial 5 decades) (typ. over temp) (%/°C) 0.2 Operating temperature range (°C) -40 to 125 Rating Catalog
Input current range (min) (nA) 0.1 Input current range (max) (mA) 10 Offset voltage (input amplifiers) (max) (mV) 2 Vs (±) (min) (V) 4.5 Vs (±) (max) (V) 12.6 Iq (max) (mA) 9 Dynamic range (typ) (dB) 160 Reference type Int Auxiliary op amps 1 Full-scale output voltage (min) (±V) 4.8 Full-scale output voltage (max) (±V) 12.3 Conformity error (initial 5 decades) (max) (%) 1.5 Conformity error (initial 5 decades) (typ. over temp) (%/°C) 0.2 Operating temperature range (°C) -40 to 125 Rating Catalog
VQFN (RGT) 16 9 mm² 3 x 3
  • Ultra-fast transient response to low current levels:
    • Settling time for 10nA to 100nA step: 240ns rising, 620ns falling (typ)
    • Settling time for 100nA to 1µA step: 60ns rising, 150ns falling (typ)
  • Wide dynamic range: 10pA to 10mA (180dB)
    • Specified from 100pA to 10mA (160dB)
  • High signal bandwidth:
    • 20MHz at 10µA to 10mA
    • 6.3MHz at 1µA
    • 90kHz at 1nA
  • High-accuracy transfer function:
    • 0.2% max log conformity error (10nA to 100µA)
  • Integrated reference current (1µA) and reference voltages (2.5V and 1.65V)
  • Additional auxiliary high-speed op amp for differential ADC drive, single-ended gain or filter blocks, and other peripheral functions
  • Single supply (4.5V to 12.6V) or dual supply (±2.25V to ±6.3V) operation
  • Specified temperature range: –40°C to +125°C
  • Small package options:
    • 3mm × 3mm VQFN
    • 1.6mm x 1.6mm DSBGA (Preview)
  • Ultra-fast transient response to low current levels:
    • Settling time for 10nA to 100nA step: 240ns rising, 620ns falling (typ)
    • Settling time for 100nA to 1µA step: 60ns rising, 150ns falling (typ)
  • Wide dynamic range: 10pA to 10mA (180dB)
    • Specified from 100pA to 10mA (160dB)
  • High signal bandwidth:
    • 20MHz at 10µA to 10mA
    • 6.3MHz at 1µA
    • 90kHz at 1nA
  • High-accuracy transfer function:
    • 0.2% max log conformity error (10nA to 100µA)
  • Integrated reference current (1µA) and reference voltages (2.5V and 1.65V)
  • Additional auxiliary high-speed op amp for differential ADC drive, single-ended gain or filter blocks, and other peripheral functions
  • Single supply (4.5V to 12.6V) or dual supply (±2.25V to ±6.3V) operation
  • Specified temperature range: –40°C to +125°C
  • Small package options:
    • 3mm × 3mm VQFN
    • 1.6mm x 1.6mm DSBGA (Preview)

The LOG200 is a wide-dynamic-range current-to-voltage amplifier specifically designed to optimize current measurements across 160dB of dynamic range with unparalleled accuracy and speed for optical communications, medical diagnostics, and industrial process-control measurements. The LOG200 features two logarithmic amplifiers followed by a high-accuracy differential amplifier that convert current signals into a voltage representing the log-compressed ratio of the two currents. The current inputs are designed to feature a high-speed response from one input, and a highly accurate reference signal on the other input, allowing for a unique combination of fast transient response and high logarithmic conformity.

The LOG200 ratio is internally set to 250mV/decade of current-to-voltage conversion. The device integrates an uncommitted high-speed amplifier to allow the output to be configured for differential or filtered responses, with a fast settling time to drive successive approximation analog-to-digital converters (SAR ADCs). The LOG200 also features a separate reference current and reference voltage designed to configure the device for optimized input current and common-mode voltages.

The LOG200 can be powered in a single-supply (4.5V to 12.6V) or dual-supply (±2.25V to ±6.3V) configuration and is specified from –40°C to +125°C.

The LOG200 is a wide-dynamic-range current-to-voltage amplifier specifically designed to optimize current measurements across 160dB of dynamic range with unparalleled accuracy and speed for optical communications, medical diagnostics, and industrial process-control measurements. The LOG200 features two logarithmic amplifiers followed by a high-accuracy differential amplifier that convert current signals into a voltage representing the log-compressed ratio of the two currents. The current inputs are designed to feature a high-speed response from one input, and a highly accurate reference signal on the other input, allowing for a unique combination of fast transient response and high logarithmic conformity.

The LOG200 ratio is internally set to 250mV/decade of current-to-voltage conversion. The device integrates an uncommitted high-speed amplifier to allow the output to be configured for differential or filtered responses, with a fast settling time to drive successive approximation analog-to-digital converters (SAR ADCs). The LOG200 also features a separate reference current and reference voltage designed to configure the device for optimized input current and common-mode voltages.

The LOG200 can be powered in a single-supply (4.5V to 12.6V) or dual-supply (±2.25V to ±6.3V) configuration and is specified from –40°C to +125°C.
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* Data sheet LOG200 Precision, High-Speed Logarithmic Amplifier With Integrated Photodiode Bias datasheet (Rev. A) PDF | HTML 02 Dec 2024
Application note Perform Accurate Optical Current Sense Measurements Using the LOG200 Logarithmic Amplifier PDF | HTML 21 Jan 2025
Certificate LOG200EVM EU Declaration of Conformity (DoC) 30 Jun 2023

Design & development

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Evaluation board

LOG200EVM — LOG200 evaluation module

The LOG200 evaluation module (EVM) is a development platform for evaluating the LOG200, which is a precision, high-speed logarithmic amplifier with integrated photodiode bias and dark-current correction. LOG200 is optimized for current measurements across 160 dB of dynamic range with unparalleled (...)

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Simulation model

LOG200 PSpice Model

SBOMCF1.ZIP (97 KB) - PSpice Model
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Simulation model

LOG200 TINA-TI Reference Design

SBOMCF2.TSC (93 KB) - TINA-TI Reference Design
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Simulation model

LOG200 TINA-TI SPICE Model

SBOMCF0.ZIP (38 KB) - TINA-TI Spice Model
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Simulation tool

PSPICE-FOR-TI — PSpice® for TI design and simulation tool

PSpice® for TI is a design and simulation environment that helps evaluate functionality of analog circuits. This full-featured, design and simulation suite uses an analog analysis engine from Cadence®. Available at no cost, PSpice for TI includes one of the largest model libraries in the (...)
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Simulation tool

TINA-TI — SPICE-based analog simulation program

TINA-TI provides all the conventional DC, transient and frequency domain analysis of SPICE and much more. TINA has extensive post-processing capability that allows you to format results the way you want them. Virtual instruments allow you to select input waveforms and probe circuit nodes voltages (...)
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