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参数资料
| 型号： | SI1102-A-GMR |
| 厂商： | Silicon Laboratories Inc |
| 文件页数： | 8/16页 |
| 文件大小： | 0K |
| 描述： | SENSOR OPTICAL DETECTOR |
| 产品培训模块： | Si1102 & Si1120 |
| 特色产品： | QuickSense? Portfolio |
| 标准包装： | 1 |
| 检测距离： | 19.7"（50cm）1.6' |
| 检测方法： | 反射 |
| 物体感测： | 非金属 |
| 安装类型： | 表面贴装 |
| 电流 - 电源： | 400mA |
| 电源电压： | 2.2 V ~ 5.25 V |
| 封装/外壳： | 8-WDFN 裸露焊盘 |
| 包装： | 标准包装 |
| 特点： | 低功率 |
| 其它名称： | 336-1819-6 |
Si11 02
3.2. Choice of LED and LED Current
In order to maximize detection distance, the use of an infrared LED is recommended. However, red (visible) LEDs
are viable in applications where a visible flashing LED may be useful and a shorter detection range is acceptable.
White LEDs have slow response and do not match the Si1102’s spectral response well; they are, therefore, not
recommended.
To maximize proximity detection distance, an LED with a peak current handling of 400 mA is recommended. With
careful system design, the duty cycle can be made low, enabling most LEDs to handle this peak current while
keeping the LED's average current draw on the order of a few microamperes.
Another consideration when choosing an LED is the LED's half-angle. An LED with a narrow half-angle focuses the
available infrared light using a narrower beam. When the concentrated infrared light encounters an object, the
reflection is much brighter. Detection of human-size objects one meter away can be achieved when choosing an
LED with a narrower half-angle and coupling it with an infrared filter on the enclosure.
3.3. Power-Supply Transients
Despite the Si1102's extreme sensitivity, it has good immunity from power-supply ripple, which should be kept
below 50 mVpp for optimum performance. Power-supply transients (at the given amplitude, frequency, and phase)
can cause either spurious detections or a reduction in sensitivity if they occur at any time within the 300 μs prior to
the LED being turned on. Supply transients occurring after the LED has been turned off have no effect since the
proximity state is latched until the next cycle. The Si1102 itself produces sharp current transients on its VDD pin,
and, for this reason, must also have a low-impedance capacitor on its supply pins. Current transients at the Si1102
supply can be up to 20 mA.
The typical LED current peak of 400 mA can induce supply transients well over 50 mVpp, but those transients are
easy to decouple with a simple R-C filter because the duty-cycle-averaged LED current is quite low. The TXO
output can be allowed to saturate without problem. Only the first 10 μs of the LED turn-on time are critical to the
detection range; this further lessens the need for large reservoir capacitors on the LED supply. In most
applications, 10 μF is adequate. If the LED is powered directly from a battery or limited-current source, it is
desirable to minimize the load peak current by adding a resistor in series with the LED’s supply capacitor.
If a regulated supply is available, the Si1102 should be connected to the regulator ’s output and the LED to the
unregulated voltage, provided it is less than 7 V. There is no power-sequencing requirement between VDD and the
LED supply.
3.4. Mechanical and Optical Implementation
It is important to have an optical barrier between the LED and the Si1102. The reflection from objects to be
detected can be very weak since, for small objects within the LED's emission angle, the amplitude of the reflected
signal decreases in proportion with the fourth power of the distance. The receiver can detect a signal with an
irradiance of 1 μW/cm 2 . An efficient LED typically can drive to a radiant intensity of 100 mW/sr. Hypothetically, if
this LED were to couple its light directly into the receiver, the receiver would be unable to detect any 1 μW/cm 2
signal since the 100 mW/cm 2 leakage would saturate the receiver. Therefore, to detect the 1 μW/cm 2 signal, the
internal optical coupling (e.g. internal reflection) from the LED to the receiver must be minimized to the same order
of magnitude (decrease by 10 5 ) as the signal the receiver is attempting to detect. As it is also possible for some
LEDs to drive a radiant intensity of 400 mW/sr, it is good practice to optically decouple the LED from the source by
a factor of 10 6 .
If an existing enclosure is being reused and does not have dedicated openings for the LED and the Si1102, the
proximity detector may still work if the optical loss factor through improvised windows (e.g. nearby microphone or
fan holes) or semi-opaque material is not more than 90% in each direction. In addition, the internal reflection from
an encased device's PMMA (acrylic glass) window (common in cellular telephones, PDAs, etc.) must be reduced
through careful component placement. To reduce the optical coupling from the LED to the Si1102 receiver, the
distance between the LED and the Si1102 should be maximized, and the distance between both components (LED
and Si1102) to the PMMA window should be minimized. The detector can also work without a dedicated window if
a semi-opaque plastic case is used.
8
Rev. 1.0
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相关代理商/技术参数 |
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|---|---|
| SI1102EK | 功能描述:光学传感器开发工具 Si1102 Mini-Proximty Sensing Demo RoHS:否 制造商:ams 工具用于评估: 接口类型: 最大工作温度: |
| SI1120_10 | 制造商:SILABS 制造商全称:SILABS 功能描述:PROXIMITY/AMBIENT LIGHT SENSOR WITH PWM OUTPUT |
| Si1120-A-GM | 功能描述:近程传感器 Proximity/Ambient Light Snsr w/PWM Out RoHS:否 制造商:Vishay Semiconductors 感应方式:Optical 感应距离:1 mm to 200 mm 电源电压:2.5 V to 3.6 V 安装风格:SMD/SMT 输出配置:Digital 最大工作温度:+ 85 C 最小工作温度:- 25 C 系列:VCNL3020 |
| SI1120-A-GMR | 功能描述:近程传感器 Proximity/Ambient Light Snsr w/PWM Out RoHS:否 制造商:Vishay Semiconductors 感应方式:Optical 感应距离:1 mm to 200 mm 电源电压:2.5 V to 3.6 V 安装风格:SMD/SMT 输出配置:Digital 最大工作温度:+ 85 C 最小工作温度:- 25 C 系列:VCNL3020 |
| SI1120EK | 功能描述:光学传感器开发工具 Si1120 Eval Kit RoHS:否 制造商:ams 工具用于评估: 接口类型: 最大工作温度: |
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