ADA4350 FET Input Analog Front End with ADC Driver

By Analog Devices Inc 60

ADA4350 FET Input Analog Front End with ADC Driver

ADI's ADA4350 is an analog front end for photodetectors or other sensors whose output produces a current proportional to the sensed parameter or voltage input applications where the system requires the user to select between very precise gain levels to maximize the dynamic range.

The ADA4350 integrates a FET input amplifier, a switching network, and an ADC driver with all functions controllable via a serial peripheral interface (SPI) or parallel control logic into a single IC. The FET input amplifier has very low voltage noise and current noise, making it an excellent choice to work with a wide range of photodetectors, sensors, or precision data acquisition systems.

The switching network in the ADA4350 allows the user individual selection of up to six different externally configurable feedback networks. By using external components for the feedback network, the user can more easily match the system to their desired photodetector or sensor capacitance. This feature also allows the use of low thermal drift resistors, if required.

The design of the switches minimizes error sources so that they add virtually no error in the signal path. The output driver can be used in either single-ended or a differential mode and is ideal for driving the input of an ADC.

The ADA4350 can operate from a single +3.3 V supply or a dual ±5 V supply, offering user flexibility when choosing the polarity of the detector. It is available in a Pb-free, 28-lead TSSOP package and is specified to operate over the -40°C to 85°C temperature range.

Multifunction pin names may be referenced by their relevant function only. 

Features
  • Low noise, low input bias current FET input amplifier
    • 90 nV/√Hz at 10 Hz
    • 5 nV/√Hz at 100 Hz
  • Integrated gain switching
    • Switch leakage ± 1 pA (typ.)
  • Integrated analog to digital converter driver
    • Differential and single-ended mode
Applications
  • Current to voltage (I to V) conversions
  • Photodiode preamplifiers
  • Chemical analyzers
  • Mass spectrometry
  • Molecular spectroscopy
  • Laser/LED receivers
  • Data acquisition systems

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