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Benchtop Photodiode Amplifier

  • Current Measurement Ranges: 100 nA to 10 mA
  • Low Noise Operation
  • Single Point Power Calibration


6 Current Ranges
Max. Resolution 10 pA

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Compatible with all of Thorlabs' Mounted Photodiodes and Biased Photodetectors.

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PDA200C Benchtop Photodiode Amplifier Connected to an SM1-Threaded Mounted Photodiode Using a BNC Cable

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The photodiode bias voltage, monitor control output (Analog Out), and grounding jack are located on the back panel of the PDA200C.


  • Transimpedance Photocurrent Amplifier
  • Extremely Low Noise Operation Over Entire Dynamic Range
  • 5 Digit Display with up to 10 pA Resolution
  • Supports Single Point Power Calibration
  • Supports Both Photodiode Polarities (CG and AG)
  • Adjustable Bias Voltage
  • Offset Compensation for Input Amplifier and Photodiode Dark Current
  • RoHS Compliant

The PDA200C Photodiode Amplifier is ideally suited for ultra low noise amplification of very small photodiode currents. It offers six current ranges from 100 nA to 10 mA full scale and provides a maximum display resolution of 10 pA. The unit supports cathode grounded (CG) and anode grounded (AG) photodiodes. This amplifier may be operated in either photovoltaic or photoconductive mode. The adjustable bias voltage provides improved linearity of the responsivity and increased frequency response. This photodiode amplifier is compatible with all of Thorlabs' mounted photodiodes and biased photodetectors. Our SM05-threaded mounted photodiodes feature a female SMA connector; to convert to BNC either an adapter cable or electrical adapter may be used.

With the updated PDA200C Series, our Photocurrent Amplifier is RoHS compliant. Additionally, the current measurement ranges were changed. The rest of the features are virtually the same as the former PDA200 Series.

PDA200C Specifications
Full Scale Current Measurement Ranges 100 nA to 10 mA (in Decade Steps)
Maximum Resolution 10 pA
Display Range 0 to 10000 (CG)
0 to -10000 (AG)
Polarity of the Photodiode Cathode Grounded (CG)
Anode Grounded (AG)
Bias Voltage 0 to -10 V (CG)
0 to +10 V (AG)
Photodiode Sensitivity (for Calibrated Power Display) 0.05 to 2 A/W
Max. Photodiode Capacitance for
Frequency Compensated Operation
10 nF
Temperature Coefficient <50 ppm/°C
Input Impedance ~0 Ω (Virtual Ground)
Photo Current Monitor Output
Output Voltage Range (Analog Output) 0 to +10 V (CG)
0 to -10 V (AG)
Conversion Coefficient 1 x 103 to 1 x 108
(Depending on Measurement Range)
Conversion Coefficient Accuracy ±5%
Noise ≤0.02%
(RMS, Full Scale of Current Measurement Range)
Load Resistance >10 kΩ
General Data
Display LED, 5 Digits
Connectors for Photodiode Input and Analog Output BNC
Chassis Ground Connector 4 mm Banana Jack
Line Voltage/
100 V, 115 V, 230 V +15% -10% each/
50 to 60 Hz
Maximum Power Consumption 10 VA
Mains Supply Overvoltage Category II (Cat II)
Operating Temperature 0 to +40 °C
Storage Temperature -40 to +70 °C
Relative Humidity Max. 80% Up to 31 °C,
Decreasing to 50% at 40 °C
Pollution Degree (Indoor Use Only) 2
Operation Altitude <2000 m
Warm-up Time for Rated Accuracy 10 min
Weight <3 kg
Dimensions without Operating Elements
(W x H x D )
146 x 66 x 290 mm³
Dimensions with Operating Elements
(W x H x D )
146 x 77 x 320 mm³

ResolutionAccuracyAnalog PD Current Output
Conversion CoefficientBandwidtha
10 mA 1 µA ± 0.05% f.s. 1 x 103 V/A ±5% 500 kHz
1 mA 100 nA ± 0.05% f.s. 1 x 104 V/A ±5% 250 kHz
100 µA 10 nA ± 0.05% f.s. 1 x 105 V/A ±5% 70 kHz
10 µA 1 nA ± 0.05% f.s. 1 x 106 V/A ±5% 20 kHz
1 µA 100 pA ± 0.05% f.s. 1 x 107 V/A ±5% 5 kHz
100 nA 10 pA ± 0.1% f.s. 1 x 108 V/A ±5% 1 kHz
  • Small signal 3 dB bandwidth of the analog output

Photodiode Input

BNC Female

BNC Female

Input Range: 100 nA ... 10 mA

Analog Control Output

BNC Female

BNC Female

0 - ±10 V, Input Resistance should be ≥ 10 kΩ.

xPDA200C Photodiode Amplifier
xOperating Manual
xPower Cord

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Posted Comments:
Posted Date:2015-02-04 18:21:47.36
Hi, Thanks for answer about source impedance. Does that mean we should not connect to a DAQ board using a 50 Ohm BNC cable ? If so, what should we use instead ?
Posted Date:2015-03-05 06:58:11.0
This is a response from Stefan at Thorlabs. Thank you again for your further questions. You are correct, you should not connect the PDA200C to a 50 Ohm BNC cable. If you connect a resistance with less than 10kOhm the internal amplifier is not able to provide the output voltage of 10V. You will get an output error. To use the PDA200C together with your DAQ board you can use a voltage follower circuit. This voltage follower circuit must have an input resistance of 10 kOhm to match the photodiode amplifier requirement, and an output resistance of 50 Ohms to work well with your DAQ board. We have contacted you directly to discuss your application in more detail.
Posted Date:2015-01-31 15:55:52.48
Please can you tell me the source impedance of the analog output ? I need this number to choose optimum settings for my DAQ board. Thank you.
Posted Date:2015-02-03 07:31:22.0
This is a response from Stefan at Thorlabs. Thank you very much for your inquiry. The source impedance of the analog output for this device is 10kOhm.
Posted Date:2014-11-17 15:46:20.173
We use a PDA200C. When I turn it on (no Diode connected), it does nothing. I checked fuses (everything alright), tried several cables and plugs, so far to no end. We are using 230V and I specificially changed the fused to 230V. So far, nobody seems to have used it (as the fuse holder was placed to 115V and we only have 230V). Is there any hidden Switch or so that I have to press (of course I tried the button on the front.
Posted Date:2014-11-18 02:32:32.0
This is a response from Stefan at Thorlabs. Thank you very much for your inquiry. I am sorry for the problems you face with our photodiode amplifier. There is no hidden switch which is supposed to be used to get the device work. Only the line voltage has to be set correctly before using the device first time. I will contact you directly for further troubleshooting.
Posted Date:2014-08-14 15:53:13.967
This feedback is concerning the Benchtop Photodiode Amplifier. Yes it will be useful. However, if the current range could be set remotely, eg over GPIB or USB, then it would be amazing. Please consider this upgrade. I want to use it for automated measurements that are in several stages, between stages I will need to change range and it would be easier to do via computer comms than manually.
Posted Date:2014-08-26 08:16:17.0
This is a response from Stefan at Thorlabs. Thank you very much for your feedback about the PDA200C. The devices of this series are apart from the display analog devices and do not support digital interfaces. Reason for that is the low processing power of the devices. At the moment it is not planned to upgrade them as this would lead to a complete redesign of the device but I forwarded your ideas to our engineers. I will contact you directly to discuss your application in detail.
Posted Date:2012-12-06 03:17:00.0
This is a response from Thomas at Thorlabs. Thank you very much for your inquiry. The PDA200C is immediately ready to use after turning on the device. It makes no difference if you connect the photodiode before or after turning on the amplifier and it is independent of using a bias voltage. If you have to turn the device off and on again for getting a measurement indicates that something is wrong with the connection or with the device itself. I will contact you directly to discuss this issue. Best Regards, Thomas
Posted Date:2012-12-03 13:47:32.817
I have a few PDA 200C that I have to recycle the power to the unit to get power readings from a FDG-50 large area detector. I have an external power source aimed at the LAD but the PDA 200C does not display any power. But when I recycle the power to the amplifier it shows detected power. Regards, Sal (Process Engineer, Molex)
Posted Date:2012-05-23 11:28:00.0
Response from Tim at Thorlabs: Thank you for sharing your ideas! Because these changes cannot be directly integrated into the current model, these suggestions would involve a full redesign of the PDA200C. Currently, our engineers are fully engaged in the development of new products, but based on your suggestions we have opened a discussion so that we may start the development of this as a future project and offer these features in a PDA200C successor.
Posted Date:2012-05-22 10:00:54.0
It would be great to have an indicator that tells the user what gain step the PDA200C is set to, when making a complex series of measurements that require changes in gain this feature would be really welcome. The current design uses 3 LEDs with 2 steps per LED which is difficult in a real world application to track. Smaller point, a number of your SI photodiodes are spec'd at 20V bias but the PDA200 only goes to 10V, i am assuming you would spec your diodes at their optimal bias hence i feel that i am not getting the best possible performance from my setup. Please consider increasing the bias to 20 V. Sincerely grateful for your attention!
Posted Date:2012-05-15 10:17:00.0
Response from Tim at Thorlabs: Thank you for contacting us. The “Err06” error message indicates a malfunction of the PCB in the device and we will need to take it in to repair. We will contact you with information and instructions.
Posted Date:2012-05-15 13:50:11.0
Dear Sir/Madam, We had a problem with PDA200C and it reports "Err06". Would you please provide us the solution to sort out this problem. Best Regards, Dr Jing Jing Wang Centre for Research on Adaptive Nanostructures and Nanodevices Trinity College Dublin Dublin 2 Ireland Telephone: 0035318964633 (Office) 0035318964617 (Photonics Laboratory) Email:
Posted Date:2010-04-22 09:44:53.0
A response from Julien at Thorlabs: "Err06" is displayed on the unit when an electronic problem occurs on the PCB leading to a malfunction of the PDA200C. The unit thus needs to be sent to us for repair. For errors not listed, the manual recommend to contact directly tech support, since those errors cannot be fixed by the user. I will contact you directly to initiate the return procedure.
Posted Date:2010-04-21 12:22:52.0
I have a PDA 200 C. When I turn it on (no diode connected) it says "Err06". Your manual says nothing about "Err06". This is terrible! The unit is quite new (about one year). Please send me the real manual?
Based on your currency / country selection, your order will ship from Newton, New Jersey  
+1 Qty Docs Part Number - Universal Price Available / Ships
PDA200C Support Documentation
PDA200CBenchtop Photodiode Amplifier
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