Overview
The OPA857TD2, produced by Texas Instruments, is an ultralow-noise, wideband, selectable-feedback resistance transimpedance amplifier. This device is specifically designed for high-performance optical systems, particularly in photodiode monitoring applications. It features a pseudo-differential output voltage and offers selectable transimpedance gain configurations, which enhance its dynamic range and flexibility. The OPA857TD2 is characterized by its fast overload recovery time and internal input protection, making it ideal for protecting the signal chain from overdrive while minimizing recovery time.
Key Specifications
| Parameter | Value |
|---|---|
| Transimpedance Gain | 5 kΩ or 20 kΩ (selectable) |
| Closed-Loop Transimpedance Bandwidth | 125 MHz (5-kΩ gain, 1.5-pF external parasitic capacitance), 105 MHz (20-kΩ gain, 1.5-pF external parasitic capacitance) |
| Input-Referred Current Noise | 15 nARMS (20-kΩ transimpedance, Brickwall filter BW = 135 MHz) |
| Overload Recovery Time | < 25 ns |
| Power Supply Voltage | 2.7 V to 3.6 V |
| Power Supply Current | 23.4 mA |
| Operating Temperature Range | -40°C to +85°C |
| Package Type | Bare die in gel pak |
Key Features
- Internal midscale reference voltage
- Pseudo-differential output voltage
- Wide dynamic range
- Ultralow input-referred current noise
- Very fast overload recovery time (< 25 ns)
- Internal input protection diode
- Selectable feedback resistance for transimpedance gain (5 kΩ or 20 kΩ)
Applications
- Photodiode monitoring
- High-speed I/V conversions
- Optical amplifiers
- CAT-scanner front-ends
Q & A
- What is the primary application of the OPA857TD2?
The OPA857TD2 is primarily used in photodiode monitoring applications. - What are the selectable transimpedance gain configurations of the OPA857TD2?
The device offers selectable transimpedance gain configurations of 5 kΩ and 20 kΩ. - What is the closed-loop transimpedance bandwidth of the OPA857TD2?
The closed-loop transimpedance bandwidth is 125 MHz for 5-kΩ gain and 105 MHz for 20-kΩ gain, both with 1.5-pF external parasitic capacitance. - What is the input-referred current noise of the OPA857TD2?
The input-referred current noise is 15 nARMS for a 20-kΩ transimpedance gain with a Brickwall filter bandwidth of 135 MHz. - How fast is the overload recovery time of the OPA857TD2?
The overload recovery time is less than 25 ns. - What is the operating temperature range of the OPA857TD2?
The operating temperature range is -40°C to +85°C. - What is the power supply voltage range for the OPA857TD2?
The power supply voltage range is 2.7 V to 3.6 V. - What is the typical power supply current of the OPA857TD2?
The typical power supply current is 23.4 mA. - Does the OPA857TD2 have internal input protection?
Yes, the OPA857TD2 has an internal input protection diode. - In what package type is the OPA857TD2 available?
The OPA857TD2 is available as a bare die in a gel pak.
