Femtoamp Bias Current Op Amps Achieve 500 MHz Gain Bandwidth for TIA & Buffer Applications

Linear Technology LTC6268 LTC6269

Linear Technology announces the LTC6268 and LTC6269, FET-input single and dual op amps, which deliver outstanding performance for high speed and high dynamic range transimpedance amplifier (TIA) and buffer applications. With just 3 fA bias current at 25 °C and 4 pA max over the entire –40 °C to 125 °C temperature range, the LTC6268/LTC6269 can resolve input currents from several femtoamps to amps. Wideband voltage and current noise is 4.3 nV/√Hz and 5.5 fA/√Hz, respectively, enabling high dynamic range circuits. Built for speed as well as precision, the LTC6268 features 500 MHz gain bandwidth product, sub-pF input capacitance and –100 dB harmonic distortion at 1 MHz. In addition to photodiode and photomultiplier (PMT) circuits, the LTC6268/9 are well suited for other high impedance sensor applications and for driving analog-to-digital converters (ADCs).

China PCB Prototype and Fabrication Manufacturer

Linear Technology - LTC6268, LTC6269

The LTC6268 data sheet features circuit and layout techniques to maximize TIA performance, with example circuits ranging from 20 kΩ transimpedance gain at 65 MHz bandwidth, to 499 kΩ transimpedance gain at 11.2 MHz bandwidth.

Linear Technology - LTC6268

The LTC6268 is available in a 6-lead SOT-23 package, as well as an 8-lead SOIC with guard pins to protect against board leakage currents. The LTC6269 is available in MSOP-8 with exposed pad and 3 mm × 3 mm DFN-10 packages.

The LTC6268 and LTC6269 are unity-gain stable and fully specified over the industrial –40 °C to 85 °C and –40 °C to 125 °C temperature ranges. Prices start at $2.90 each for the LTC6268 and $4.90 for the LTC6269 each in 1000-piece quantities.

Summary of Features: LTC6268

  • Gain Bandwith Product: 500 MHz
  • –3 dB Bandwith (A = 1): 350 MHz
  • Low Input Bias Current:
    • ±3 fA Typ. Room temperature
    • 4 pA Max at 125°C
  • Current Noise (100 kHz): 5.5 fA/√Hz
  • Voltage Noise (1 MHz): 4.3 nV/√Hz
  • Extremely Low CIN: 450 fF
  • Rail-to-Rail Output
  • Slew Rate: 400 V/μs
  • Supply Range: 3.1 V to 5.25 V
  • Quiescent Current: 16.5 mA
  • Harmonic Distortion (2 Vp.p):
    • –100 dB at 1 MHz
    • –80 dB at 10 MHz
  • Operating Temp Range: –40 °C to 125 °C
  • Single in 8-Lead SO-8, 6-Lead TSOP-23 Packages
  • Dual 8-Lead MS8, 3 mm × 3 mm 10-Lead DFN 10 Packages


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