Electronic Components Datasheet Search |
|
TSL245R-LF Datasheet(PDF) 4 Page - TEXAS ADVANCED OPTOELECTRONIC SOLUTIONS |
|
TSL245R-LF Datasheet(HTML) 4 Page - TEXAS ADVANCED OPTOELECTRONIC SOLUTIONS |
4 / 10 page TSL245R INFRARED LIGHT-TO-FREQUENCY CONVERTER TAOS060D − SEPTEMBER 2007 4 r r Copyright E 2007, TAOS Inc. The LUMENOLOGY r Company www.taosinc.com APPLICATION INFORMATION Power-supply considerations Power-supply lines must be decoupled by a 0.01-μF to 0.1-μF capacitor with short leads placed close to the TSL245R (Figure 5). A low-noise power supply is required to minimize jitter on output pulse. TSL245R Timer / Port MCU 0.1 μF VDD 2 3 1 Figure 5. Typical TSL245R Interface to a Microcontroller Device Operational Details The frequency at the output pin (OUT) is given by: fO = fD + (Re) (Ee) where: fO is the output frequency fD is the output frequency for dark condition (Ee = 0) Re is the device responsivity for a given wavelength of light given in kHz/(μW/cm2) Ee is the incident irradiance in μW/cm2 fD is an output frequency resulting from leakage currents. As shown in the equation above, this frequency represents a light-independent term in the total output frequency fO. At very low light levels, this dark frequency can be a significant portion of fO. The dark frequency is temperature dependent. For optimum performance of any given device over the full output range, the value of fD should be measured (in the absence of light) and later subtracted from subsequent light measurement (see Figure 1). Output interface 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. Measuring the frequency The choice of interface and measurement technique depends on the desired resolution and data-acquisition rate. For maximum data-acquisition rate, period-measurement techniques are used. Period measurement requires the use of a fast reference clock with available resolution directly related to reference-clock rate. The technique is employed to measure rapidly varying light levels or to make a fast measurement of a constant light source. Maximum resolution and accuracy may be obtained using frequency-measurement, pulse-accumulation, or integration techniques. Frequency measurements provide the added benefit of averaging out random- or high-frequency variations (jitter) resulting from noise in the light signal. Resolution is limited mainly by available counter registers and allowable measurement time. Frequency measurement is well suited for slowly varying or constant light levels and for reading average light levels over short periods of time. Integration, the accumulation of pulses over a very long period of time, can be used to measure exposure — the amount of light present in an area over a given time period. |
Similar Part No. - TSL245R-LF |
|
Similar Description - TSL245R-LF |
|
|
Link URL |
Privacy Policy |
ALLDATASHEET.COM |
Does ALLDATASHEET help your business so far? [ DONATE ] |
About Alldatasheet | Advertisement | Datasheet Upload | Contact us | Privacy Policy | Link Exchange | Manufacturer List All Rights Reserved©Alldatasheet.com |
Russian : Alldatasheetru.com | Korean : Alldatasheet.co.kr | Spanish : Alldatasheet.es | French : Alldatasheet.fr | Italian : Alldatasheetit.com Portuguese : Alldatasheetpt.com | Polish : Alldatasheet.pl | Vietnamese : Alldatasheet.vn Indian : Alldatasheet.in | Mexican : Alldatasheet.com.mx | British : Alldatasheet.co.uk | New Zealand : Alldatasheet.co.nz |
Family Site : ic2ic.com |
icmetro.com |