VT5366

LED selection

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8

LED selection

8.1

Overview

There are a number of LEDs from a range of suppliers which will work well with the VT5366.

It is the responsibility of the customer to ensure that the chosen LED works in their specific

implementation. There are various price/performance trade-offs which may be made if the

customer chooses to do so.

8.2

Key LED parameters

The VT5366 system requires a bright visible RED LED in a standard 5 mm (T1 3/4)

forward current of 20mA. The key LED parameters are listed in

Table 19.

8.3

VCSEL & IR Illumination

The 366 sensor will operate over a wide range of illuminant wavelengths. For devices

operating at approx 850nm (IR LED or VCSEL), the on-die automatic exposure controller

(AEC) will compensate for the change in sensitivity compared to 640nm (red LED).

Navigation performance may be improved by increasing the illuminated device drive.

Table 19.

Key LED parameters

Parameter

Recommended value

Notes

Diameter

5 mm

Important for fit with lens

Length

8.6 mm

Important for fit with lens

Material

AlInGaP

For long-term reliability

Luminous intensity (@20mA)

900 mcd

Minimum value

Viewing angle

Half intensity

Mechanical accuracy

Accuracy of the die positioning

within the LED body

Color

Red

Wavelength

640 nm +/- 50 nm

Relative Illumination at sensor

plane for a circle of 1.1 mm

diameter

80%

Illumination value required for

Red/IR Led and VCSEL

≥