LIGHT-TO-DIGITAL CONVERTER

1 TSL2560, TSL2561 LIGHT-TO-DIGITAL CONVERTERTAOS059N MARCH 20091 The LUMENOLOGYr CompanyrrCopyright E 2009, TAOS Human Eye ResponseDProgrammable Interrupt Function withUser-Defined Upper and Lower ThresholdSettingsD16-Bit digital Output with SMBus (TSL2560)at 100 kHz or I2C (TSL2561) Fast-Mode at400 kHzDProgrammable analog Gain and IntegrationTime Supporting 1,000,000-to-1 DynamicRangeDAutomatically Rejects 50/60-Hz LightingRippleDLow Active Power ( mW Typical) withPower Down ModeDRoHS Compliant DescriptionThe TSL2560 and TSL2561 are light-to-digitalconverters that transform light intensity to a digitalsignal output capable of direct I2C (TSL2561) orSMBus (TSL2560) interface. Each device com-bines one broadband photodiode (visible plusinfrared) and one infrared-responding photodiodeon a single CMOS integrated circuit capable ofproviding a near-photopic response over aneffective 20-bit dynamic range (16-bit resolution).

2 Two integrating ADCs convert the photodiodecurrents to a digital output that represents theirradiance measured on each channel. This digitaloutput can be input to a microprocessor whereilluminance (ambient light level) in lux is derivedusing an empirical formula to approximate thehuman eye response. The TSL2560 devicepermits an SMB-Alert style interrupt, and theTSL2561 device supports a traditional level styleinterrupt that remains asserted until the firmwareclears useful for general purpose light sensing applications, the TSL2560/61 devices are designed particularlyfor display panels (LCD, OLED, etc.) with the purpose of extending battery life and providing optimum viewingin diverse lighting conditions. Display panel backlighting, which can account for up to 30 to 40 percent of totalplatform power, can be automatically managed.

3 Both devices are also ideal for controlling keyboard illuminationbased upon ambient lighting conditions. Illuminance information can further be used to manage exposurecontrol in digital cameras. The TSL2560/61 devices are ideal in notebook/tablet PCs, LCD monitors, flat-paneltelevisions, cell phones, and digital cameras. In addition, other applications include street light control, securitylighting, sunlight harvesting, machine vision, and automotive instrumentation Advanced Optoelectronic Solutions Klein Road S Suite 300 S Plano, TX 75074 S (972) 673-07596 SDA5 INT4 SCLPACKAGE T6-LEAD TMB(TOP VIEW)VDD 1 ADDR SEL 2 GND 3 PACKAGE CS6-LEAD CHIPSCALE(TOP VIEW)VDD 1 ADDR SEL 2 GND 36 SDA5 INT4 SCLP ackage Drawings are Not to ScalePACKAGE FNDUAL FLAT NO-LEAD(TOP VIEW)6 SDA5 INT4 SCLVDD 1 ADDR SEL 2 GND 3 PACKAGE CL6-LEAD ChipLED(TOP VIEW)

4 4 SCL3 ADDR SEL2 GNDSDA 5 INT 6 VDD 1 TSL2560, TSL2561 LIGHT-TO-DIGITAL CONVERTERTAOS059N MARCH 20092rrCopyright E 2009, TAOS LUMENOLOGYr Block DiagramTwo-Wire Serial InterfaceAddress SelectInterruptSDAVDD = V to VChannel 0 Visible and IRChannel 1IR OnlyCommandRegisterADCR egisterINTSCLADDR SELI ntegrating A/D ConverterDetailed DescriptionThe TSL2560 and TSL2561 are second-generation ambient light sensor devices. Each contains two integratinganalog-to- digital converters (ADC) that integrate currents from two photodiodes. Integration of both channelsoccurs simultaneously. Upon completion of the conversion cycle, the conversion result is transferred to theChannel 0 and Channel 1 data registers, respectively. The transfers are double-buffered to ensure that theintegrity of the data is maintained. After the transfer, the device automatically begins the next integration to the device is accomplished through a standard, two-wire SMBus or I2C serial , the TSL256x device can be easily connected to a microcontroller or embedded controller.

5 Noexternal circuitry is required for signal conditioning, thereby saving PCB real estate as well. Since the outputof the TSL256x device is digital , the output is effectively immune to noise when compared to an analog TSL256x devices also support an interrupt feature that simplifies and improves system efficiency byeliminating the need to poll a sensor for a light intensity value. The primary purpose of the interrupt function isto detect a meaningful change in light intensity. The concept of a meaningful change can be defined by the userboth in terms of light intensity and time, or persistence, of that change in intensity. The TSL256x devices havethe ability to define a threshold above and below the current light level. An interrupt is generated when the valueof a conversion exceeds either of these OptionsDEVICEINTERFACEPACKAGE LEADSPACKAGE DESIGNATORORDERING NUMBERTSL2560 SMBusChipscaleCSTSL2560 CSTSL2560 SMBusTMB-6 TTSL2560 TTSL2560 SMBusDual Flat No-Lead 6 FNTSL2560 FNTSL2560 SMBusChipLED-6 CLTSL2560 CLTSL2561I2 CChipscaleCSTSL2561 CSTSL2561I2 CTMB-6 TTSL2561 TTSL2561I2 CDual Flat No-Lead 6 FNTSL2561 FNTSL2561I2 CChipLED-6 CLTSL2561 CLTSL2560, TSL2561 LIGHT-TO-DIGITAL CONVERTERTAOS059N MARCH 20093 The LUMENOLOGYr CompanyrrCopyright E 2009, TAOS FunctionsTERMINALNAMECS, T, SEL23 ISMBus device select three-stateGND32 Power supply ground.

6 All voltages are referenced to or SMB Alert interrupt open serial clock input terminal clock signal for SMBus serial serial data I/O terminal serial data I/O for Maximum Ratings over operating free-air temperature range (unless otherwise noted) Supply voltage, VDD (see Note 1) V.. digital output voltage range, VO V to V.. digital output current, IO 1 mA to 20 mA.. Storage temperature range, Tstg 40 C to 85 C.. ESD tolerance, human body model 2000 V.. Stresses beyond those listed under absolute maximum ratings may cause permanent damage to the device. These are stress ratings only, andfunctional operation of the device at these or any other conditions beyond those indicated under recommended operating conditions is notimplied. Exposure to absolute-maximum-rated conditions for extended periods may affect device 1.

7 All voltages are with respect to Operating ConditionsMINNOMMAXUNITS upply voltage, free-air temperature, TA 3070 CSCL, SDA input low voltage, VIL , SDA input high voltage, Characteristics over recommended operating free-air temperature range (unlessotherwise noted)PARAMETERTEST CONDITIONSMINTYPMAXUNITIS upply currentPower AVINT SDA output low voltage3 mA sink , SDA output low voltage6 mA sink current 55 ATSL2560, TSL2561 LIGHT-TO-DIGITAL CONVERTERTAOS059N MARCH 20094rrCopyright E 2009, TAOS LUMENOLOGYr Characteristics, High Gain (16 ), VDD = 3 V, TA = 25 C, (unless otherwise noted) (seeNotes 2, 3, 4, 5)PARAMETERTEST CONDITIONSCHANNELTSL2560T, FN, & CLTSL2561T, FN & CLTSL2560CS, TSL2561 CSUNITPARAMETERTEST CONDITIONSCHANNELMINTYPMAXMINTYPMAXUNIT foscOscillator frequency690735780690735780kHzDark ADC count valueE0T402 msCh00404countsDark ADC count valueEe = 0, Tint = 402 msCh10404countsT178 msCh06553565535 Tint > 178 msCh16553565535 Full scale ADC countT101 msCh03717737177countsFull scale ADC countvalue (Note 6)

8 Tint = 101 msCh13717737177countsT13 7 msCh050475047 Tint = msCh150475047 p = 640 nm, Tint = 101 msCh075010001250 p = 640 nm, Tint = 101 msEe = W/cm2Ch1200counts p = 940 nm, Tint = 101 msCh070010001300countsADC count value p = 940 nm, Tint = 101 msEe = 119 W/cm2Ch1820 ADC count value p = 640 nm, Tint = 101 msCh075010001250 p = 640 nm, Tint = 101 msEe = 41 W/cm2Ch1190counts p = 940 nm, Tint = 101 msCh070010001300counts p = 940 nm, Tint = 101 msEe = 135 W/cm2Ch1850 ADCtlti 640 nm T101 ms015020025014019024 ADC count value ratio: p = 640 nm, Tint = 101 count value ratio:Ch1/Ch0 940 nm T101 ms0690820950700851Ch1/Ch0 p = 940 nm, Tint = 101 640 nm T101 responsivity p = 640 nm, Tint = 101 ( W/ReIrradiance responsivity 940 nm T101 ( W/cm2) p = 940 nm, Tint = 101 )Fluorescent light source: Ch03635 RIlluminance responsivityFluorescent light source: Tint = 402 responsivityIncandescent light source: Ch0144129counts/luxIncandescent light source: Tint = 402 msCh17267 ADC count value ratio:Fluorescent light source: Tint = 402 count value ratio:Ch1/Ch0 Incandescent light source: 05052Ch1/Ch0 Incandescent light source: Tint = 402 light source: responsivity,Fluorescent light source: Tint = 402 responsivity,low gain mode (Note 7)Incandescent light source: light source: Tint = 402 (Sensor Lux) / (actual Lux) high gainFluorescent light source: Tint = 402 (actual Lux), high gainmode (Note 8)Incandescent light source: Tint = 402 , TSL2561 LIGHT-TO-DIGITAL CONVERTERTAOS059N MARCH 20095 The LUMENOLOGYr CompanyrrCopyright E 2009, TAOS : 2.

9 Optical measurements are made using small-angle incident radiation from light-emitting diode optical sources. Visible 640 nm LEDsand infrared 940 nm LEDs are used for final product testing for compatibility with high-volume The 640 nm irradiance Ee is supplied by an AlInGaP light-emitting diode with the following characteristics: peak wavelength p = 640 nm and spectral halfwidth = 17 The 940 nm irradiance Ee is supplied by a GaAs light-emitting diode with the following characteristics: peak wavelength p = 940 nm and spectral halfwidth = 40 Integration time Tint, is dependent on internal oscillator frequency (fosc) and on the integration field value in the timing register asdescribed in the Register Set section. For nominal fosc = 735 kHz, nominal Tint = (number of clock cycles)/fosc. Field value 00: Tint = (11 918)/fosc = msField value 01: Tint = (81 918)/fosc = 101 msField value 10: Tint = (322 918)/fosc = 402 msScaling between integration times vary proportionally as follows: 11/322 = (field value 00), 81/322 = (field value 01),and 322/322 = 1 (field value 10).

10 6. Full scale ADC count value is limited by the fact that there is a maximum of one count per two oscillator frequency periods and alsoby a 2-count offset. Full scale ADC count value = ((number of clock cycles)/2 2)Field value 00: Full scale ADC count value = ((11 918)/2 2) = 5047 Field value 01: Full scale ADC count value = ((81 918)/2 2) = 37177 Field value 10: Full scale ADC count value = 65535, which is limited by 16 bit register. This full scale ADC count value is reachedfor 131074 clock cycles, which occurs for Tint = 178 ms for nominal fosc = 735 Low gain mode has 16 lower gain than high gain mode: (1/16 = ).8. The sensor Lux is calculated using the empirical formula shown on p. 22 of this data sheet based on measured Ch0 and Ch1 ADCcount values for the light source specified. Actual Lux is obtained with a commercial luxmeter.