Datasheet

L8957
Features Applications
LED
Infrared LED
l Low price
Uses low cost lens
l Optical encoders
l Optical switches
Low cost LED ideal for optical encoders
L8957 is an infrared LED using a low-cost lens and available at a lower price than other products up to now.
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■ Absolute maximum ratings (Ta=25 °C, unless otherwise noted)
Parameter Symbol Condition Value Unit
Reverse voltage V
R
5 V
Forward current I
F
80 mA
Forward current reduction rate - 0.67 mA/°C
Pulse forward current I
FP
Pulse width=10 µs
Duty ratio=1 %
0.5 A
Pulse forward current reduction rate - 4.2 mA/°C
Power dissipation P 150 mW
Operating temperature Topr -30 to +85 °C
Storage temperature Tstg -40 to +100 °C
■ Electrical and optical characteristics (Ta=25 °C)
Parameter Symbol Condition Min. Typ. Max. Unit
Peak emission wavelength
λ
p I
F
=30 mA 840 870 900 nm
Spectral half width
∆λ
I
F
=30 mA - 45 - nm
Optical output *
1
Pe I
F
=30 mA 1.5 2.1 - mW
Forward voltage V
F
I
F
=30 mA - 1.5 1.65 V
Reverse current I
R
V
R
=5 V - - 5 µA
Spot light size *
2
Bw I
F
=30 mA 4.8 *
3
5.4 - mm
Cut-off frequency *
4
fc I
F
=30 mA ± 4 mAp-p 25 40 - MHz
*1: Measured with a photodiode (active area:
φ
8 mm) installed 10 mm away from LED stem undersurface.
*2: Full width at half maximum of beam spot measured with an image sensor installed 13 mm away from LED stem undersurface.
*3: Reference value
*4: Frequency at which the optical output drops by -3 dB from that at 100 kHz.
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