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EPC134-CSP6 参数 Datasheet PDF下载

EPC134-CSP6图片预览
型号: EPC134-CSP6
PDF下载: 下载PDF文件 查看货源
内容描述: 光接收机放大器 [Photo-receiver Amplifier]
分类和应用: 放大器接收机
文件页数/大小: 11 页 / 547 K
品牌: EPC [ ESPROS PHOTONICS CORP ]
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epc134/epc135/epc136/epc137/epc138/epc139  
Application Information  
Light Barrier Application  
The following circuit is recommended to operate the epc134/135/136/137/138/139 as a photo diode amplifier in a single beam light barrier:  
+VLED  
Light path  
D2  
D1  
C1  
C3  
R1  
VDD  
digital output  
to logic, PLC  
or μC  
PD  
CN  
OUT  
VN  
epc13x  
Type  
T1  
from digital  
oscillator or  
μC output  
C2  
VSS  
R2  
GND LED  
Recommended Components Values  
R1: 27k(epc135/137/138), 6.8k(epc134) and 4.7k (epc136/139) (bias resistor). Sensitivity can be reduced by the reduction of this resistor.  
R2: dependent on the required LED current  
C1: Usually not needed. May be up to 100 pF (refer to section 'Photodiode Capacitance').  
C2: 33nF (DC input current filter capacitor)  
C3: 100nF or greater (power supply filter capacitor)  
D1: PIN photo diode, BP104 (OSRAM) or similar devices  
D2: IR LED, TSML1000 (Vishay) or similar devices  
Working Principle  
The IR LED D2 emits light pulses which are sent towards the photo diode D1. If there is no obstacle between the two devices, the light pulse  
generates an AC current (IPD) in the reverse biased photo diode D1 into the pin PD. IPD is proportional to the power of the light pulse. If IPD is  
greater than the trigger threshold of the circuitry in the device, a pulse at the pin OUT is generated. If IPD is greater than the trigger threshold  
for the light reserve (IPDres), a second pulse at the output is generated. The length of the output pulse is given by tOUT. Once a light pulse is gen-  
erated by the IR LED, a next light pulse must not be generated until the recovery time t REC (max.).  
Design Precautions  
The sensitivity at pin PD is very high in order to achieve a long operation range of light barriers even without lenses in front of the IR LED  
and/or the photo diode. Thus, the pin PD is very sensitive to EMI. Special care should be taken to keep the PCB track  
at pin PD as short as possible (a few mm only!). This track should be kept away from the IR LED signal tracks and  
from other sources which may induce unwanted signals. It is strongly recommended to cover the chip, the photodiode  
and all passive components around the chip with a metal shield. A recommended part is shown in the following figure:  
The pins at the bottom are to solder the shield to the PCB with electrical connection to VDD. The hole in the front is  
the opening window for the photo diode. The back side of the PCB below the sensitive area (D1, C1, R1, epc13x)  
shall be a polygon connected to VDD to shield the circuit from the back side. C1 must be of high mechanical stability  
Recommended EMC  
(no piezoelectric effect) in order to avoid unwanted signals by mechanical shock or vibration.  
shield  
Ambient Light  
Photodiode DC current can be generated by ambient light, e.g. sun light. DC currents at pin PD do not generate an output signal. However, if  
IPDDC is above the stated value, the input is saturated which blocks the detection of AC current pulses.  
Photodiode Capacitance  
If the photodiode capacitance is below the specified value, the system becomes more sensitive to power supply ripple voltage at higher fre -  
quencies (>200kHz). This sensitivity can be reduced by a parallel capacitor to the photodiode. However, this measure reduces the detection  
sensitivity. If the photo diode capacity is above the specified value, a lower detection sensitivity and a higher sensitivity spread results.  
© 2011 ESPROS Photonics Corporation  
Characteristics subject to change without notice  
8
Datasheet epc13x digital - V2.1  
www.espros.ch