OPA1S2385 - 250-MHz, CMOS Transimpedance Amplifier (TIA) with Integrated Switch and Buffer

The OPA1S2384 and OPA1S2385 (OPA1S238x) combine high bandwidth, FET-input operational amplifiers with a fast SPST CMOS switch designed for applications that require the tracking and capturing of fast signals.

By providing a 250-MHz gain bandwidth product and rail-to-rail input/output swings in single-supply operation, the OPA1S238x is capable of wideband transimpedance gain and large output signal swing simultaneously. Low input bias current and voltage noise (6 nV/√Hz) make it possible to amplify extremely low-level input signals for maximum signal-to-noise ratio.

The characteristics of the OPA1S238x make this device ideally suited for use as a wideband photodiode amplifier.

In addition, the CMOS switch and subsequent buffer amplifier allow the OPA1S238x to be easily configured as a fast sample-and-hold circuit. The external hold capacitor and post-gain options make the OPA1S238x easily adoptable to a wide range of speed and accuracy requirements. Note that the OPA1S2384 closes the internal switch with a logic-high signal, and the OPA1S2385 closes the internal switch with a logic-low signal.

The OPA1S238x are optimized for low-voltage operation from as low as +2.7 V up to +5.5 V. These devices are specified for a temperature range of –40°C to +85°C.

• Wide Bandwidth: 250 MHz
• High Slew Rate: 150 V/µs
• Rail-to-Rail Input/Output (I/O)
• Fast Settling
• Low Input Bias Current: 3 pA
• High Input Impedance: 10¹³ Ω || 2 pF
• SPST Switch:
  • Low On-Resistance: 4 Ω
  • Low Charge Injection: 1 pC
  • Low Leakage Current: 10 pA
• Flexible Configuration:
  • Transimpedance Gain
  • External Hold Capacitor
  • Post-Gain
• Single Supply: +2.7 V to +5.5 V
• Quiescent Current: 9.2 mA
• Small Package: 3-mm × 3-mm SON-10
• OPA1S2384: Internal Switch Active High
• OPA1S2385: Internal Switch Active Low