ADL5308
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ADL5308

Fast Response 188 dB Range (10 pA to 25 mA) Logarithmic Converter

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Info : RECOMMENDED FOR NEW DESIGNS tooltip
Info : RECOMMENDED FOR NEW DESIGNS tooltip
Part Details
Part Models 2
1ku List Price Starting From $9.82
Features
  • Fast transient response (IPD stepped from 220 μA to 10 nA)
    • Rise/fall time: <2.4 μs
    • 2 dB Electrical (1 dB optical) settling time: <3.5 μs
  • Flat Frequency Response/No Undershoot
  • Bandwidth: 970 kHz at IINP = 10 nA
  • Accurately trimmed logarithmic response
    • Logarithmic slope: 200 mV/dec
    • Logarithmic conformance error: ±0.2 dB at 25°C (IINP from 10 nA to 1 mA)
  • Ratio input for direct optical gain measurements
  • Comparator with adjustable hysteresis and latch enable
  • Analog and digital comparator reference
  • I2C adjustable
    • Adaptive photodiode bias
    • Comparator reference level
  • Minimal external components are required
  • 34 dB PSRR at 20 kHz and IINP = 10 nA
  • 2 mm × 3 mm, 14-terminal LGA package
Additional Details
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The ADL5308 is a logarithmic transimpedance amplifier optimized for wide dynamic range signal level monitoring in fiber optic systems.

It produces an accurate, temperature-compensated output voltage proportional to the logarithm of the ratio between the input current at pin INP, and a reference current. The reference current can either be generated internally or externally provided through the IREF interface (LOG-ratio detection). The logarithmic slope and intercept are both accurately trimmed to a nominal value of 200 mV/decade and 10 pA respectively.

The low-impedance VLOG logarithmic output has enough drive capability to drive a wide range of analog-to-digital converters (ADCs) and other circuits and its gain can be adjusted by adding a resistor-divider driving the FB pin.

A built-in fast comparator provides a compact solution to compare the logarithmic output to an external reference level, either programmed through I2C or supplied through the CREF interface. The comparator has adjustable hysteresis and an optional output latch function using the HYST pin.

Adaptive photodiode (PD) biasing is supported through the PDB pin. At a low diode current, the reverse PD bias is kept small to minimize the dark current. At higher input currents, the bias voltage scales linearly with the current to avoid nonlinearity due to PD saturation. The starting bias level as well as the scale factor at higher currents are configurable through I2C.

The ADL5308 is specified for operation from −40°C to +105°C ambient temperature and is offered in a small 2 mm × 3 mm, 14-terminal LGA package.

Applications

  • Optical power monitoring
  • Erbium-doped fiber amplifiers (EDFA)
  • Part Models 2
    1ku List Price Starting From $9.82

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    Documentation

    Documentation

    Part Model Pin/Package Drawing Documentation CAD Symbols, Footprints, and 3D Models
    ADL5308ACCZ
    • HTML
    • HTML
    ADL5308ACCZ-R7
    • HTML
    • HTML
    Software & Part Ecosystem

    Software & Part Ecosystem

    Evaluation Kit

    Evaluation Kits 1

    reference details image

    EVAL-ADL5308

    Evaluating the ADL5308 Fast Response 188 dB Range (10 pA to 25 mA) Logarithmic Converter

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    EVAL-ADL5308

    Evaluating the ADL5308 Fast Response 188 dB Range (10 pA to 25 mA) Logarithmic Converter

    Evaluating the ADL5308 Fast Response 188 dB Range (10 pA to 25 mA) Logarithmic Converter

    Features and Benefits

    • Full-featured evaluation board for the ADL5308
    • Supports external electrical input or on-board photodiode (PD) for optical input
    • On-chip or external PD bias (PDB)
    • Comparator reference and output connectors with adjustable hysteresis

    Product Detail

    The ADL5308-EVALZ evaluation board allows evaluation of the ADL5308 logarithmic converter IC.

    The ADL5308 is a monolithic logarithmic transimpedance amplifier, optimized for measurement of low frequency, and wide dynamic range signal power in fiber optic systems. It produces an output voltage proportional to the logarithm of the ratio between the input current at pin INP, and an internal reference current. The reference current can also be supplied externally through the IREF interface.

    The logarithmic slope and intercept are both factory-trimmed to a nominal value of 200 mV/dec and 10 pA respectively. Both can be adjusted through the I2C interface.

    Full specifications on the ADL5308 are available in the ADL5308 data sheet available from Analog Devices, Inc., and must be consulted with the user guide when using the ADL5308-EVALZ evaluation board.

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