Large Area Fast Amplified Si Photodiode

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Amplified, large-area (7 mm2) photodetector based on a Si photodiode, with fast response and Johnson-noise limited performance.  A low-noise JFET isolates the photodiode capacitance from a fast (140 MHz) op amp configured as a transimpedance amplifier, allowing speed typically only found in detectors with an order of magnitude smaller sensor size. An integrated high slew-rate (1.3 V/ns) line driver delivers up to 9 Vpp into a 50 Ω load. The module is packaged in a standard lens tube with 1.035"-40 threads for convenient integration. The sensor head includes an ultra low noise voltage regulator and can be powered directly from a ±12V lab bench supply or a commercially available power brick via a 3-pin M8 connector.

Regular price $289.00 Sale price $289.00
Front view of fast transimpedance amplifier (TIA-F-01) showing photodiode active area.

  • Large area Si PIN photodiode
  • Compact package (1-inch diameter lens tube) for convenient integration
  • Fast response (61 ns rise time)
  • High gain (0.2 V/µW @ 850nm)
  • High speed line driver for large amplitude output into 50 Ω
  • Dynamic range from pW to µW
  • Johnson-noise limited from 250 Hz to 100 kHz

  • Sensitive synchronous detection
  • Fast time domain monitoring
  • Characterization of faint diffuse radiation

The sensor head comprises a Si PIN photodiode, a JFET input stage, a transimpedance amplifier, and an output stage capable of driving a 50 Ω load. The photodiode is reverse biased so incident light is converted to a photocurrent. This photocurrent is converted to a voltage by a transimpedance amplifier with a large feedback resistor (330 kΩ). A JFET follower drives the anode of the photodiode. This reduces the effective input capacitance at the op amp summing junction and boosts the detection bandwidth. The transimpedance amplifier is AC coupled to a low-noise, high-voltage, current-feedback amplifier configured as a non-inverting 3 dB gain stage capable of driving 9 Vpp into 50 Ω. When driving a high impedance load the sensor gain is 660 kV/A and 330 kV/A when used with a 50 Ω terminator. The signal output is via a SMA RF coax connector.

Contact us to discuss custom solutions, pricing and lead-time. Example customizations include:

  • Blue / green optimized silicon PIN diode
  • Infrared / near-infrared InGaAs diode
  • Choice of transimpedance gain
  • DC-coupling


Wavelength400-1100 nm
Sensitive area2.65 mm x 2.65 mm
Quantum efficiency0.9 @ 850 nm
Responsivity0.62 A/W @ 850 nm
Gain330 kV/A into 50Ω
Bandwidth (3dB)3.8 Hz - 1.6 MHz
Rise time61 ns
Noise (0.3-100 kHz)77 nV Hz-1/2
NEP @ 850 nm380 fW Hz-1/2
Maximum output9 Vppinto 50Ω
Power supply±12 V @ 250 mA
Power connector3-pin M8
Signal connectorSMA
Lens tube1.035”-40 x 2”
Operating temp5-30° C


Large Bandwidth with Large Area

A record of a single nanosecond duration laser pulse (650 nm). The rise time is 61 ns. The fall time is 210 ns. The light source is an Eikonal Nanosecond Pulsed Laser Diode (NLD-01).


Johnson-noise Limited Performance

Measured power spectral density.  Below 100 kHz, noise (77 nV Hz-1/2) is flat and dominated by the Johnson noise of the 330 kΩ feedback resistor.  At higher frequencies, the noise increases linearly up to the rolloff frequency of the amplifier. For a derivation of Johnson noise and application to a transimpedance amplifier see our tutorial.

High Dynamic Range Optical Density Measurement with a Synchronous Amplifier

In this video, we’ll use a synchronous amplifier (Eikonal SA-01) to make high dynamic range measurements of the transmission of an optical component. We’ll use a modulated laser diode (Eikonal LDFC-01) as a light source, and a large area amplified photodiode (Eikonal TIA-F-01) as the photodetector. In this example, we’ll measure the optical transmission of laser safety glasses. We'll use the Eikonal modules as a system to make measurements sensitive to a part in 10,000.