The TSL237 light-to-frequency converter combines a silicon photodiode and a current-to-frequency converter on a single monolithic CMOS-integrated circuit. The output is a square wave (50% duty cycle) with frequency directly proportional to light intensity. Because it is TTL-compatible, the output allows direct interface to a microcontroller or other logic circuitry. The device has been temperature-compensated for the ultraviolet-to-visible light range of 320 nm to 700 nm and responds over the light range of 320 nm to 1050 nm.
- Communicates directly with a microcontroller
- Single-supply operation
- Compact 3-lead clear plastic package
- High-resolution conversion of light intensity to frequency with no external components
- Camera exposure
- Dimming displays
- Machine vision
Note: Power-supply lines must be decoupled by a 0.01 µF to 0.1 µF capacitor with short leads placed close to the TSL235R. The output of the device is designed to drive a standard TTL or CMOS logic input over short distances. If lines greater than 12 inches are used on the output, a buffer or line driver is recommended.
- Nonlinearity Error (Typically 0.2% at 100 kHz)
- Stable 150 ppm/°C Temperature Coefficient
- Supply Voltage: 2.7 - 5.5 VDC
- Operating Temperature range: -25 - 70 °C
- Typical current draw: 2 mA
- Output Frequency: 40 - 60 kHz