Features and Benefits

  • Metal Can and Ceramic Package Versions of this part are Obsolete: LF198AH, LF198H, LF398AH, LF398H, LF398J8. The LF398AN8 is Obsolete.
  • 4µs Typical Acquisition Time
  • Guaranteed 0.01% Max. Gain Error
  • 2mV Typ. Offset Voltage
  • 2.5mV Max. Hold Step
  • Very Low Feedthrough 80dB Min.
  • High Input Impedance Under All Conditions
  • Logic Inputs Compatible with All Logic Families
  • DIP8 Package
  • For SOP8 Package, see LF398S

Product Details

Metal Can and Ceramic Package Versions of this part are Obsolete: LF198AH, LF198H, LF398AH, LF398H, LF398J8. The LF398AN8 is Obsolete.

The LF398 is a precision sample and hold amplifier which uses a combination of bipolar and junction FET transistors to provide precision, high speed, and long hold times. A typical offset voltage of 2mV and gain error of 0.004% allow this sample and hold amplifier to be used in 12-bit systems. Dynamic performance canbe optimized by proper selection of the external hold capacitor. Acquisition times can be as low as 4µs for small capacitors while hold step and droop errors can be held below 0.1mV and 30µV/sec respectively when using larger capacitors.

The LF398 is fixed at unity gain with 1010Ω input impedance independent of sample/hold mode. The logic inputs are high impedence differential to allow easy interfacing to any logic family without ground loop problems. A separate offset adjust pin can be used to zero the offset voltage in either the sample or hold mode. Additionally, the hold capacitor can be driven with an external signal to provide precision level shifting or "differencing" operation. The device will operate over a wide supply voltage range from ±5V to ±18V with very little change in performance, and key parameters are specified over this full supply range.


  • 12-Bit Data Acquisition Systems
  • Ramp Generators
  • Analog Switches
  • Staircase Generators
  • Sample and Difference Circuits

Product Lifecycle icon-recommended Production

At least one model within this product family is in production and available for purchase. The product is appropriate for new designs but newer alternatives may exist.

Design Resources

ADI has always placed the highest emphasis on delivering products that meet the maximum levels of quality and reliability. We achieve this by incorporating quality and reliability checks in every scope of product and process design, and in the manufacturing process as well.  "Zero defects" for shipped products is always our goal.

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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.

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