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AD549:  Ultralow Input-Bias Current Operational Amplifier

The AD549* is a monolithic electrometer operational amplifier with very low input bias current. Input offset voltage and input offset voltage drift are laser trimmed for precision performance. The part’s ultralow input current is achieved with “Topgate” JFET technology, a process development exclusive to Analog Devices, Inc. This technology allows fabrication of extremely low input current ...More

AD549:  Ultralow Input-Bias Current Operational Amplifier

Product Description

The AD549* is a monolithic electrometer operational amplifier with very low input bias current. Input offset voltage and input offset voltage drift are laser trimmed for precision performance. The part’s ultralow input current is achieved with “Topgate” JFET technology, a process development exclusive to Analog Devices, Inc. This technology allows fabrication of extremely low input current JFETs compatible with a standard junction isolated bipolar process. The 1015 Ω common-mode impedance, which results from the bootstrapped input stage, ensures that the input current is essentially independent of common-mode voltage.

The AD549 is suited for applications that require very low input current and low input offset voltage. It excels as a preamp for a wide variety of current output transducers, such as photo-diodes, photomultiplier tubes, or oxygen sensors. The AD549 can also be used as a precision integrator or low droop sample and hold. The AD549 is pin compatible with standard FET and electrometer op amps, allowing designers to upgrade the performance of present systems at little additional cost.

The AD549 is available in a TO-99 hermetic package. The case is connected to Pin 8 so that the metal case can be independently connected to a point at the same potential as the input terminals, minimizing stray leakage to the case. The AD549 is available in four performance grades. The J, K, and L versions are rated over the commercial temperature range of 0°C to +70°C. The S grade is specified over the military temperature range of −55°C to +125°C and is available processed to MIL-STD-883B, Rev. C. Extended reliability plus screening is also available. Plus screening includes 168 hour burn-in, as well as other environmental and physical tests derived from MIL-STD-883B, Rev. C.

Product Highlights

  1. The AD549 input currents are specified, 100% tested, and guaranteed after the device is warmed up. They are guaranteed over the entire common-mode input voltage range.
  2. The AD549 input offset voltage and drift are laser trim-med to 0.25 mV and 5 μV/°C (AD549K), and to 1 mV and 20 μV/°C (AD549J).
  3. A maximum quiescent supply current of 700 μA minimizes heating effects on input current and offset voltage.
  4. AC specifications include 1 MHz unity gain bandwidth and 3 V/μs slew rate. Settling time for a 10 V input step is 5 μs to 0.01%.

* Protected by U.S. Patent No. 4,639,683.

Applications

  • Electrometer amplifier
  • Photodiode preamp
  • pH electrode buffer
  • Vacuum ion gauge measurement

    • Data Sheet, Rev. G, 7/07

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    • Ultralow input-bias current
      60 fA maximum (AD549L)

      250 fA maximum (AD549J)
    • Input-bias current guaranteed over common-mode voltage range
    • Low offset voltage
      0.25 mV maximum (AD549K)

      1.00 mV maximum (AD549J)
    • Low offset drift
      5 μV/°C maximum (AD549K)

      20 μV/°C maximum (AD549J)
    • Low power
      700 μA maximum supply current

      Low input voltage noise
    • 4 μV p-p 0.1 Hz to 10 Hz
    • MIL-STD-883B parts available

    Connection Diagram for AD549

    Pricing, Packaging & Availability

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    Model
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    Status
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    • Pre-Release: The model has not been released to general production, but samples may be available.
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    Package Description
    The package for this IC (i.e. DIP, SOIC, BGA). An Evaluation Board is a board engineered to show the performance of the model, the part is included on the board.

    For detailed drawings and chemical composition please consult our  Package Site

    Pin Count
    Pin Count is the number of pins, balls, or pads on the device. Pin-out diagrams & pin function descriptions may be found in the datasheet.

    Temperature Range
    This is the acceptable operating range of the device. The various ranges specified are as follows:
    • Commercial: 0 to +70 degrees Celsius
    • Military : -55 to +125 degrees Celsius
    • Industrial: Temperature ranges may vary by model. Please consult the datasheet for more information.
    • Automotive: -40 to +125 degrees Celsius
    Price
    The USA list pricing shown is for BUDGETARY USE ONLY, shown in United States dollars (FOB USA per unit for the stated volume), and is subject to change. International prices may differ due to local duties, taxes, fees and exchange rates. For volume-specific price or delivery quotes, please contact your local Analog Devices, Inc. sales office or authorized distributor. Pricing displayed for Evaluation Boards and Kits is based on 1-piece pricing.

    Production Availability
    This is the date Analog Devices, Inc. anticipates that the product will ship from the warehouse. Most orders ship within 48 hours of this date.Once an order has been placed, Analog Devices, Inc. will send an Order Acknowledgement email to confirm your delivery date. It is important to note the scheduled dock date on the order entry screen. We do take orders for items that are not in stock, so delivery may be scheduled at a future date. Also, please note the warehouse location for the product ordered. We have warehouses in the United States, Europe and Southeast Asia. Transit times from these sites may vary.
    Sample availability may be better than production availability. Please enter samples into your cart to check sample availability.

    RoHS Compliant
    Due to environmental concerns, ADI offers many of our products in lead-free versions. For more information about lead-free parts, please consult our Pb (Lead) free information page.

    View PCN
    This is the list of Product Change Notifications (PCN) published on the web for this model. Click on the link to access PCN Information.Only select pre-2009 PCN�s are available on-line. To obtain a pre-2009 PCN, contact your ADI Sales Rep. For more information on ADI's PCN process, please visit our PCN Policy Statement page

    *The USA list pricing shown is for BUDGETARY USE ONLY, shown in United States dollars (FOB USA per unit for the stated volume), and is subject to change. International prices may differ due to local duties, taxes, fees and exchange rates. For volume-specific price or delivery quotes, please contact your local Analog Devices, Inc. sales office or authorized distributor. Pricing displayed for Evaluation Boards and Kits is based on 1-piece pricing.
    **Sample availability may be better than production availability. Please enter samples into your cart to check sample availability.