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Built around a vcsel (vertical cavity surface-emitting laser), RPR-0720 measures only 2 x 1 x 0.55mm including its photodiodes and control IC.
The internal IC operates over 1.7 to 3.6V, drawing 16μA (typ for 50μs mode, 35μA max) when it is not driving the laser and 300μA (500μA max) when it is. Standby is at 700nA (5μA max).
It provides a controllable constant current sink for the vcsel, which has a separate power terminal and will work over 2.7 to 4.5V, allowing it to be connected directly to a Li-ion battery without needing its own regulator.
Digging through the data sheet (following a comment below) reveals that, via the I2C interface, Vcsel drive can be set at 3, 4 or 5mA, for 50, 100, 200 or 400μs, with a repetition period of 5, 10, 50, 100 or 500ms.
Proximity detection range is 0 to 15mm (white surface) and can be as far as 50mm – near and far photodiodes within can be used separately or together.
Operation is over -30 to +85°C.
For development, evaluation board RPR-0720-EVK can be combined with a custom software package.
“Going forward, Rohm will continue to develop sensing products combining original light receiving and emitting elements to further improve energy savings and convenience,” said the company.
Applications are foreseen detecting the attachment and detachment of wireless ear buds as well as in smart watches, gaming console controllers and VR headsets.
Find the RPR-0720 product page here
I had no idea that solid state lasers had gotten so small or would lase with just 0.3mA. Very impressive! The product page says the wavelength is rather far into the IR range, which seems like the only choice for a low voltage device. Quite an interesting part.
Good Morning Mr Kurt
It is an impressive little device – I forgot to look at the wavelenghts.
Thanks for drawing to my attention how confusing the article was regarding laser current (my bad). 0.3mA is the current drawn by the controller IC during emission – so I have altered the article to add laser currents and durations: 3-5mA is the short answer.