L8957_07 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
s Absolute maximum ratings (Ta=25 °C, unless otherwise noted)
Parameter
Symbol
Condition
Reverse voltage
VR
Forward current
IF
Forward current reduction rate
-
Pulse forward current
IFP
Pulse width=10 µs
Duty ratio=1 %
Pulse forward current reduction rate -
Power dissipation
P
Operating temperature
Topr
Storage temperature
Tstg
Value
5
80
0.67
0.5
4.2
150
-30 to +85
-40 to +100
Unit
V
mA
mA/°C
A
mA/°C
mW
°C
°C
s Electrical and optical characteristics (Ta=25 °C)
Parameter
Symbol
Condition
Min.
Typ.
Max.
Unit
Peak emission wavelength
λp IF=30 mA
840
870
900
nm
Spectral half width
∆λ IF=30 mA
-
45
-
nm
Optical output *¹
Pe IF=30 mA
1.5
2.1
-
mW
Forward voltage
VF IF=30 mA
-
1.5
1.65
V
Reverse current
IR VR=5 V
-
-
5
µA
Spot light size *²
Bw IF=30 mA
4.8 *³
5.4
-
mm
Cut-off frequency *⁴
fc IF=30 mA ± 4 mAp-p
25
40
-
MHz
*1: Measured with a photodiode (active area: φ8 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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