S9648-200SB_15 Datasheet, PDF (4/5 Pages) Hamamatsu Corporation – Photo IC diode

Photo IC diode
S9648-200SB
Operating voltage, output characteristics
Figure 2 shows the photocurrent vs. reverse voltage characteristics (light source: LED) for the measurement circuit example in Figure
1. The output curves are shown for illuminance levels. The output curves rise from a reverse voltage (rising voltage) of approximately 0.7
V (±10%).
To protect the photo IC diode from excessive current, a 150 Ω (±20%) protection resistor is inserted in the circuit. Reverse voltage VR
when the photo IC diode is saturated is the sum of Vbe(ON) and the voltage drop across the protection resistor Rin [Equation (1)].
VR = Vbe(ON) + IL × Rin ............ (1)
The photodiode’s reverse voltage (VR) is expressed by Equation (2) according to the voltage drop across the external resistor. This is
indicated as load lines in Figure 2.
VR = Vcc - IL × RL ............ (2)
In Figure 2, the intersections between the output curves and the load lines are the saturation points. From these points, the maximum
detectable light level can be specified. Since the maximum light level is determined by the supply voltage (Vcc) and load resistance (RL),
adjust them according to the operating conditions.
Note: The temperature characteristics of Vbe(ON) is approximately -2 mV/°C, and that of the protection resistor is approximately
0.1%/°C.
[Figure 1] Measurement circuit example
IL
RL
(external resistor)
Rin=150 Ω ± 20%
(internal protection resistor)
Vcc
Photo IC
diode
[Figure 2] Photocurrent vs. reverse voltage
5
(Typ. Ta=25 °C)
1600 lx
4
Saturation
region
approx. 1260 lx
3
1380 lx
Internal protective
resistance Rin: approx. 150 Ω
1150 lx
2 ^Saturation
region
approx. 650 lx
1
Load line
Vcc=5 V, RL=1 kΩ
Load line
Vcc=3 V, RL=1 kΩ
880 lx
600 lx
300 lx
KPICC0128EC
0
0
1
2
3
4
5
Rising voltage
Vbe(ON)≈0.7 V
Reverse voltage (V)
KPICB0107EC
4