L8957 Datasheet, PDF (1/2 Pages) Hamamatsu Corporation – Low cost LED ideal for optical encoders

LED
Infrared LED
L8957
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.
Features
l Low price
Uses low cost lens
Applications
l Optical encoders
l Optical switches
I Absolute maximum ratings (Ta=25 °C, unless otherwise noted)
Parameter
Symbol
Value
Reverse voltage
V4
5
Forward current
I.
80
Forward current reduction rate
-
0.67
Pulse forward current
I.2
0.5
Pulse forward current reduction rate -
7
Power dissipation
P
150
Operating temperature
Topr
-30 to +85
Storage temperature
Tstg
-40 to +100
Unit
V
mA
mA/°C
A
mA/°C
mW
°C
°C
I Electrical and optical characteristics (Ta=25 °C)
Parameter
Symbol
Condition
Min.
Typ.
Max.
Unit
Peak emission wavelength
lp I.=50 mA
840
870
900
nm
Spectral half width
Dl I.=50 mA
-
45
-
nm
Radiant flux
fe I.=50 mA
3.4
5.8
-
mW
Forward voltage
V. I.=50 mA
-
1.6
1.75
V
Reverse current
I4 V4=5 V
-
-
5
µA
Spot light size *
Bw I.=30 mA
4.5
5.0
-
mm
Optical output *
Pe I.=30 mA
1.0
2.0
-
mW
Cut-off frequency *^!
fc I.=30 mA ± 4 mAp-p
25
40
-
MHz
*1: Full width at half maximum, measurement distance (from the image sensor to the bottom surface of L8957’s base)=10 mm
*2: Measurement distance [from the photodiode (active area: f8 mm) to the bottom surface of L8957’s base]=10 mm
*3: Frequency at which the optical output drops by -3 dB from that at 100 kHz.
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