DataSheet Report – Hamamatsu Photoreflector

Posted on Tuesday 14 February 2006

My Choice for my Datasheet report was the Hamamatsu Photoreflector.

Introduction: “This photo IC is a combination of a high power infared LED and a low voltage photo IC. The Photo IC consists fo a high sensitivity photodiode, amplifier, schmitt trigger circuit, and output phototransistor on a single chip.” Included is a link to a wikipedia definition of a Schmitt trigger:

Applications:The manufacturer lists two commercial applications, Paper detection in copiers and printers or end detection in tape recorders,VTR etc. I found this sensor on the Acroname site where customers use the chip for detection of wheel rotation on their robots.(see photo below)


Electrical Characteristics:This sensor requires 5v. The photo IC output range is -0.5 to +7v. Supply Voltage to the photo IC is a minimum of 2.2v and a maximum of 7v. The “Transfer Characteristics” apply to the reflective nature of what the Photo IC is reading and are as follows L to H Threshold input current 10 mA with a white paper of 90% reflectivity.

Output Pins/Schematic:
This schematic is pretty simple (it would seem). The output would lead to the pic, I don’t have code to read this chip as of yet.

Questions:I have many questions concerning the properties of this sensor and also of the notations used in the DataSheet.

1. What is Threshold input current and what is the formula RL=1.2kΩ, d=3mm

2. Hysterisis:”IFHL/IFLH” of 0.8, what is this? are these relative/absolute amounts of hysterisis…

Link to Datasheet pdf:

Below is the Datasheet image:

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