Photodiodes are pn-junction devices generally made from Silicon, a Group IV Element from the Periodic Chart, however Gallium Arsenide (a III-V compound semiconductor) has been used to produce photodiodes with a very narrow sensitivity range in the near-IR. Both types of photodiodes collect impinging photons at the semiconductor junction, creating hole-electron pairs which are proportional to the intensity of radiation within the range of sensitivity of the parent material. Silicon photodiodes have peak sensitivity in the near-infrared, but extend down through the visible range and up to just over 1-micron wavelength. GaAs photodiodes have peak sensitivity at about 850nm and do not extend more than 25 to 50nm above and below that peak.

Photodiodes offer the fastest response time of all silicon-based sensors, but signal levels are in the microamp to tens of microamps range.

Silicon Photodiodes

CLD370F provides a 4X larger active area than other 5mm (T-1 3/4) packaged photodiodes.

Part Number (1)ISC mA (min)ID (4)nA (max)ID (5) nA (max)CJ (6)pFƟHP(7)deg. (typ)Active Area L” x W”
CLD156100 (2)100400100.122 x .222
CLD156R100 (2)50400100.122 x .222
CLD16050 (2)10100200100.125 x .125
CLD2404020201440.060 x .060
CLD240E13202014140.060 x .060
CLD240W1320201470.060 x .060
CLD370F60 typ. (3)302560.08 x .08

Aluminum Gallium Arsenide Photodiodes

Part Number (1)Responsivity A/W (min)ID (9) nA (max)ID nA (max)CJ (6) pFƟHP (7)deg. (typ)Active Area L” x W”
CLD3400.5 (8)1.017090.040 x .040

CLD340 provides excellent high temperature characteristics and responds only to infrared radiation.



  1. Click on a part number for datasheet.
  2. Radiation source is a tungsten lamp operating at a color temperature of 2854K, Ee = 1.0mW/cm2, Ee = 0.
  3. Measured at VR = 5V, Ee = 1.0mW/cm², λp = 850nm.
  4. Measured under dark conditions, VF = 100mW, Ee= 0.
  5. A dark condition exists when further irradiation shielding does not reduce ID
  6. Measured under dark conditions, VR = 10V, Ee = 0.
  7. A dark condition exists when further irradiation shielding does not reduce ID
  8. Measured with zero bias, f = 1MHz.
  9. Acceptance angle at half power points.
  10. Responsivity at 880nm, VR = 0.
  11. Measured at VR =5 V, Ee = 0.