4GHz amplifier has input bias current below 1pA over temperature

May 14, 2015 // By Graham Prophet
LTC6268-10 single, and dual LTC6269-10, are 4GHz FET-input op amps for high dynamic range and high speed transimpedance amplifier (TIA) applications.

These decompensated amplifiers extend the speed and dynamic range capabilities of this ultralow bias current op amp family for applications with a gain of 10 or higher. Input bias current is 0.9 pA max over the -40°C to 85°C temperature range and 4 pA max over the entire -40°C to 125°C temperature range. Wideband voltage and current noise is 4 nV/√Hz and 7 fA/√Hz, respectively. With 0.45 pF input capacitance and 1000 V/µsec slew rate, the LTC6268-10 and LTC6269-10 are suited for photodiode and photomultiplier (PMT) circuits, high impedance sensor applications and for driving analogue-to-digital converters (ADCs).

The LTC6268-10 data sheet features circuit and layout techniques to maximise TIA performance, with example circuits ranging from 20 kΩ transimpedance gain at 210 MHz bandwidth, to 402 kΩ transimpedance gain at 34 MHz bandwidth. The LTC6268-10 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 LTC6269-10 is available in an MSOP-8 with exposed pad and in 3 x 3 mm DFN-10 packages. The LTC6268-10 and LTC6269-10 are 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 LTC6268-10 and $4.90 each for the LTC6269-10 (each 1000).

Linear Technology; www.linear.com/product/LTC6268-10 / www.linear.com/product/LTC6269-10

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