TSL230, TSL230A, TSL230B PROGRAMMABLE LIGHT-TO-FREQUENCY CONVERTERS SOES007B – OCTOBER 1992 – REVISED MARCH 1994 • • • • High-Resolution Conversion of Light Intensity to Frequency With No External Components Programmable Sensitivity and Full-Scale Output Frequency Communicates Directly With a Microcontroller • • • • Single-Supply Operation Down to 2.7 V, With Power-Down Feature Absolute Output Frequency Tolerance of ± 5% (TSL230B) Nonlinearity Error Typically 0.2% at 100 kHz Stable 100 ppm/°C Temperature Coefficient Advanced LinCMOS Technology description The TSL230, TSL230A, and TSL230B programmable light-to-frequency converters combine a configurable silicon photodiode and a current-to-frequency converter on single monolithic CMOS integrated circuits. The output can be either a pulse train or a square wave (50% duty cycle) with frequency directly proportional to light intensity. The sensitivity of the devices is selectable in three ranges, providing two decades of adjustment. The full-scale output frequency can be scaled by one of four preset values. All inputs and the output are TTL compatible, allowing direct two-way communication with a microcontroller for programming and output interface. An output enable (OE) is provided that places the output in the high-impedance state for multiple-unit sharing of a microcontroller input line. The devices are available with absolute-output-frequency tolerances of ± 5% (TSL230B), ± 10% (TSL230A), or ± 20% (TSL230). Each circuit has been temperature compensated for the ultraviolet-to-visible-light range of 300 nm to 700 nm. The devices are characterized for operation over the temperature range of – 25°C to 70°C. mechanical data The TSL230, TSL230A, and TSL230B are packaged in a clear plastic 8-pin dual-in-line package. The photodiode area is typically 1.36 mm2 (0.0029 in2) (S0 = S1 = H). Pin 1 Pin 2 Pin 3 Pin 4 Pin 5 Pin 6 Pin 7 Pin 8 10,92 (0.430) 9,40 (0.370) S0 S1 OE GND VCC OUT S2 S3 8 5 8,26 (0.325) 7,62 (0.300) 0,76 (0.030) D NOM 6,60 (0.260) 6,10 (0.240) 1,91 (0.075) 1,02 (0.040) 1 1,65 (0.065) 1,14 (0.045) 5,08 (0.200) 3,94 (0.155) 15° TYP (Center of active area coincides with package center.) C L 4 0,51 (0.020) R NOM 4 Places 7° MAX TYP 1,91 (0.075) 1,02 (0.040) Seating Plane 0,51 (0.020) R MAX 4 Places 105° 90° 8 Places 0,30 (0.012) 0,20 (0.008) 1,27 (0.050) 0,51 (0.020) 1,52 (0.060) 0,38 (0.015) 7,62 (0.300) TP* 1,65 (0.065) 1,14 (0.045) 3,81 (0.150) 3,18 (0.125) 0,56 (0.022) 0,36 (0.014) 2,54 (0.100) TP* *True position when unit is installed. ALL LINEAR DIMENSIONS ARE IN MILLIMETERS AND PARENTHETICALLY IN INCHES LinCMOS is a trademark of Texas Instruments Incorporated. Copyright 1994, Texas Instruments Incorporated PRODUCTION DATA information is current as of publication date. Products conform to specifications per the terms of Texas Instruments standard warranty. Production processing does not necessarily include testing of all parameters. POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 5–3 TSL230, TSL230A, TSL230B PROGRAMMABLE LIGHT-TO-FREQUENCY CONVERTERS SOES007B – OCTOBER 1992 – REVISED MARCH 1994 Terminal Functions TERMINAL I/O Selectable Options DESCRIPTION NAME NO. GND 4 OE 3 I Enable for fO (active low) OUT Ground 6 O Scaled-frequency (fO) output S0, S1 1, 2 I Sensitivity-select inputs S2, S3 7, 8 I fO scaling-select inputs Supply voltage VDD 5 S1 S0 SENSITIVITY L L H H L H L H Power Down 1× 10× 100× S3 S2 fO SCALING (divide-by) L L H H L H L H 1 2 10 100 functional block diagram Output Light Photodiode Current-to-Frequency Converter OE S0 S1 S2 S3 absolute maximum ratings over operating free-air temperature range (unless otherwise noted)† Supply voltage, VDD (see Note 1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.5 V Input voltage range, all inputs, VI . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . – 0.3 V to VDD + 0.3 V Operating free-air temperature range, TA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . – 25°C to 70°C Storage temperature range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . – 25°C to 85°C Lead temperature 1,6 mm (1/16 inch) from case for 10 seconds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 260°C † Stresses beyond those listed under “absolute maximum ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated under “recommended operating conditions” is not implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability. NOTE 1: All voltage values are with respect to GND. recommended operating conditions Supply voltage, VDD High-level input voltage, VIH Low-level input voltage, VIL VDD = 4.5 V to 5.5 V VDD = 4.5 V to 5.5 V POST OFFICE BOX 655303 NOM 2.7 5 • DALLAS, TEXAS 75265 MAX UNIT 6 V V 0 VDD 0.8 – 25 70 °C 2 Operating free-air temperature range, TA 5–4 MIN V TSL230, TSL230A, TSL230B PROGRAMMABLE LIGHT-TO-FREQUENCY CONVERTERS SOES007B – OCTOBER 1992 – REVISED MARCH 1994 electrical characteristics at TA = 25°C, VDD = 5 V (unless otherwise noted) PARAMETER VOH VOL High-level output voltage IIH IIL High-level input current IDD TEST CONDITIONS MIN TYP 4 4.3 IOH = – 4 mA IOL = 4 mA Low-level output voltage 0.17 Low-level input current Power-on mode Supply current 2 Power-down mode Full-scale frequency† MAX V 0.26 V 1 µA 1 µA 3 mA 10 µA 1.1 λ ≤ 700 nm, –25°C ≤ TA ≤ 70°C Temperature coefficient of output frequency UNIT MHz ± 100 kSVS Supply voltage sensitivity VDD = 5 V ±10% † Full-scale frequency is the maximum operating frequency of the device without saturation. ppm/°C 0.5 %/ V operating characteristics at VDD = 5 V, TA = 25°C PARAMETER TEST CONDITIONS S0 = H, S1 = S2 = S3 = L, Ee = 130 mW/cm2, λp = 670 nm TSL230 fO Output frequency MIN TYP MAX MIN TYP MAX 0.8 1 1.2 0.9 1 1.1 0.95 1 1.05 0.1 10 0.1 10 0.1 10 1 1.2 1 1.1 1 1.05 0.13 10 0.13 10 0.13 10 1 1.2 1 1.1 1 1.05 0.5 10 0.5 10 0.5 10 Hz 550 ns Ee = 0 S1 = H, S0 = S2 = S3 = L 0.8 Ee = 0, S0 = S1 = H, S2 = S3 = L tw S2 = S3 = L 125 Output pulse duration S2 or S3 = H Nonlinearity ‡ fO = 0 MHz to 10 kHz fO = 0 MHz to 100 kHz fO = 0 MHz to 1 MHz 550 0.9 0.9 125 550 0.95 0.95 125 Hz MHz Hz MHz 1/2fO ± 0.1% 1/2fO ± 0.1% %F.S. ± 0.2% ± 0.2% ± 0.2% %F.S. ± 0.5% ± 0.5% ± 0.5% %F.S. 100 Step response to full-scale step input 1 pulse of new frequency plus 1 µs Response time to output enable (OE) MHz 1/2fO ± 0.1% Recovery from power down Response time to programming change UNIT MAX 0.8 S0 = S1 = H, S2 = S3 = L, Ee = 1.3 mW/cm2, λp = 670 nm TSL230B TYP Ee = 0, S0 = H, S1 = S2 = S3 = L S1 = H, S0 = S2 = S3 = L, Ee = 13 mW/cm2, λp = 670 nm TSL230A MIN 100 s 100 µs 150 ns 2 periods of new principal frequency plus 1 µs§ 50 150 50 150 50 † Full-scale frequency is the maximum operating frequency of the device without saturation. ‡ Nonlinearity is defined as the deviation of fO from a straight line between zero and full scale, expressed as a percent of full scale. § Principal frequency is the internal oscillator frequency, equivalent to divide-by-1 output selection. POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 5–5 TSL230, TSL230A, TSL230B PROGRAMMABLE LIGHT-TO-FREQUENCY CONVERTERS SOES007B – OCTOBER 1992 – REVISED MARCH 1994 TYPICAL CHARACTERISTICS OUTPUT FREQUENCY vs IRRADIANCE PHOTODIODE SPECTRAL RESPONSIVITY 1 1000 10 0.8 Normalized Responsivity fO – Output Frequency – kHz 100 TA = 25°C VDD = 5 V λp = 670 nm TA = 25°C S2 = S3 = L S0 = H, S1 = H 1 0.1 S0 = L, S1 = H 0.6 0.4 0.2 0.01 S0 = H, S1 = L 0.001 0.001 0.01 0.1 1 10 10 0 1k 0 300 10 k 100 k 1 M 400 Ee – Irradiance – µW/cm2 500 600 fO(dark) – Dark Frequency – Hz VDD = 5 V Ee = 0 S2 = S3 = L 1 S0 = H, S1 = H S0 = L, S1 = H 0.01 S0 = H, S1 = L 0.001 0 25 50 75 TA – Temperature – °C Temperature Coefficient of Output Frequency – ppm/ °C 100 0.0001 – 25 TEMPERATURE COEFFICIENT OF OUTPUT FREQUENCY vs WAVELENGTH OF INCIDENT LIGHT 10000 VDD = 5 V TA = 25°C to 70°C 8000 6000 4000 2000 0 300 400 500 600 700 Figure 4 POST OFFICE BOX 655303 800 900 λ – Wavelength of Incident Light – nm Figure 3 5–6 1000 1100 Figure 2 DARK FREQUENCY vs TEMPERATURE 0.1 900 800 λ – Wavelength – nm Figure 1 10 700 • DALLAS, TEXAS 75265 1000 TSL230, TSL230A, TSL230B PROGRAMMABLE LIGHT-TO-FREQUENCY CONVERTERS SOES007B – OCTOBER 1992 – REVISED MARCH 1994 TYPICAL CHARACTERISTICS OUTPUT FREQUENCY vs SUPPLY VOLTAGE 1.005 Normalized Output Frequency 1.004 TA = 25°C fO = 1 MHz 1.003 1.002 1.001 1 0.999 0.998 0.997 0.996 0.995 2.5 3 3.5 4 4.5 5 5.5 6 VDD – Supply Voltage – V Figure 5 APPLICATION INFORMATION power-supply considerations For optimum device performance, power-supply lines should be decoupled by a 0.01-µF to 0.1-µF capacitor with short leads. 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. sensitivity adjustment Sensitivity is controlled by two logic inputs, S0 and S1. Sensitivity is adjusted using an electronic iris technique – effectively an aperture control – to change the response of the device to a given amount of light. The sensitivity can be set to one of three levels: 1x, 10x or 100x, providing two decades of adjustment. This allows the responsivity of the device to be optimized to a given light level while preserving the full-scale output-frequency range. Changing of sensitivity also changes the effective photodiode area by the same factor. POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 5–7 TSL230, TSL230A, TSL230B PROGRAMMABLE LIGHT-TO-FREQUENCY CONVERTERS SOES007B – OCTOBER 1992 – REVISED MARCH 1994 APPLICATION INFORMATION output-frequency scaling Output-frequency scaling is controlled by two logic inputs, S2 and S3. Scaling is accomplished on chip by internally connecting the pulse-train output of the converter to a series of frequency dividers. Divided outputs available are divide-by 2, 10, 100, and 1 (no division). Divided outputs are 50 percent-duty-cycle square waves while the direct output (divide-by 1) is a fixed-pulse-width pulse train. Because division of the output frequency is accomplished by counting pulses of the principal (divide-by 1) frequency, the final-output period represents an average of n (where n is 2, 10 or 100) periods of the principal frequency. The output-scaling-counter registers are cleared upon the next pulse of the principal frequency after any transition of the S0, S1, S2, S3, or OE lines. The output goes high upon the next subsequent pulse of the principal frequency, beginning a new valid period. This minimizes the time delay between a change on the input lines and the resulting new output period in the divided output modes. In contrast with the sensitivity adjust, use of the divided outputs lowers both the full-scale frequency and the dark frequency by the selected scale factor. The frequency-scaling function allows the output range to be optimized for a variety of measurement techniques. The divide-by-1 or straight-through output can be used with a frequency counter, pulse accumulator, or high-speed timer (period measurement). The divided-down outputs may be used where only a slower frequency counter is available, such as a low-cost microcontroller, or where period measurement techniques are used. The divide-by-10 and divide-by-100 outputs provide lower frequency ranges for high resolution-period measurement. 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. Using the divide-by-2 output, data can be collected at a rate of twice the output frequency or one data point every microsecond for full-scale output. Period measurement requires the use of a fast reference clock with available resolution directly related to reference-clock rate. Output scaling can be used to increase the resolution for a given clock rate or to maximize resolution as the light input changes. Period measurement is used to measure rapidly varying light levels or to make a very 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. 5–8 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 IMPORTANT NOTICE Texas Instruments and its subsidiaries (TI) reserve the right to make changes to their products or to discontinue any product or service without notice, and advise customers to obtain the latest version of relevant information to verify, before placing orders, that information being relied on is current and complete. All products are sold subject to the terms and conditions of sale supplied at the time of order acknowledgement, including those pertaining to warranty, patent infringement, and limitation of liability. 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