The ISL29030A is a built-in IR led driver and i2c optical-to-digital converter interface (compatible with SMBus) that integrates ambient and IR. This device uses two separate ADCs that measure ambient light simultaneously and in parallel proximity. The flexible interrupt scheme is designed for use with the smallest microcontrollers. For ambient light sensor (ALS) data conversion, the ADC converts photodiode current (with a light sensitivity range of 2000 lux) for 100 ms per sample. The ADC rejects flicker noise caused by 50 Hz/60 Hz artificial light sources. The IDES pin provides and measurement light ( 420 μa fsr). For Proximity Sensor (Prox) data conversion, the built-in driver turns on the external IR LED and the Proximity Sensor ADC converts the reflected IR intensity to a number. The analog-to-digital converter rejects ambient infrared noise (such as sunlight) and has a conversion time of 540 μs. The ISL29030A provides ALS and proximity sensing with a typical normal operating current of 138µA (110µA for sensor and internal circuits; about 28µA for external LEDs, at 220ma current pulses, repeating every 100µs for 800ms or less). The ISL29030A uses hardware pins and software bits to indicate that an interrupt event has occurred. ALS interrupts are defined as measurements outside the setup window. A proximity interruption is defined as the threshold limit. The user can configure the device so that the ALS near-interrupt occurs simultaneously, up to 16 times in succession, before the interrupt pin is activated. The ISL29030A is designed for an ambient temperature range of -40°C to +85°C. It is packaged in a clear lead-free 8-lead ODFN package.

feature

Operates under all light sources including sunlight Dual ADCs measure ALS/Prox simultaneously Smart interrupt scheme simplifies microcontroller code Ambient light sensing Simple output code proportional to lux Sensor response selectable 125/2000 lux range Analog 420µA output pin IAL proportional to lux Net 100µs pulses with 110ma or 220ma amplitude - Periodic sleep time between pulses up to 800ms Ambient IR noise cancellation (including sunlight) Smart and flexible interrupts /8/16 Continuous Trigger Ultra Low Power 138µA DC typical supply current for ALS/Prox sensing - 110µA for sensor and internal circuitry - 28µA typical for external IR LED (assuming 220mA every 800ms 100µs) <1.0µA supply current when powered down Easy to use setup registers; wait for interrupts 3.63V sensor power supply lead-free (RoHS compliant)

application

Display and Keypad Dimming and Proximity Sensing: - Mobile Devices: Smartphones, PDAs, GPS - Computing Devices: Notebooks, Netbooks - Consumer Devices: LCD TVs, Digital Photo Frames, Digital Cameras Industrial and Medical Lighting and Proximity Sensing.

Working Principle I2C Interface ISL29030A The I2C interface slave address is internally hardwired as 0B1000100. An example of a one-byte read is shown. The I2C bus master always drives the SCL (clock) line, while the master or slave can drive the SDA (data) line. Each I2C transaction begins with the master asserting a START condition (SDA falls while SCL falls and remains high). The first transmitted byte consists of seven address bits and an R/W bit by the host. The slave is responsible for every byte transferred. Each I2C transaction ends with the master asserting a stop state (SDA goes high, SCL remains high). For more information on the I2C standard, please refer to the Philips I2C specification document. Photodiode and ADCISL29030A contains two photodiode arrays for converting photons (light) into current. ALS photodiodes are constructed to simulate the wavelength response curve of the human eye to visible light. The ALS photodiode current output goes through a 12-bit ADC within 100ms. These 12 bits can be read by the ADC to complete the conversion as the als converter is a charge-balanced, integrated, 12-bit ADC. Charge balancing works best in the presence of periodic AC noise. Integrating a high rejection rate over 100 ms By choosing the smallest integer, both 50 Hz and 60 Hz lights will flash for two cycles of 50 Hz/60 Hz frequency. The proximity sensor is an 8-bit ADC, in a similar fashion. When proximity sensing is enabled, the IRDR pin drives a user-supplied IR LED that emits IR that reflects off an object back to the ISL29030A, and a sensor converts the reflected IR wave to a current signal within 0.54ms. The ADC subtracts the IR readings before and after the LED is driven (removing ambient IR, such as sunlight) and converts this value to a digital count stored in register 0x8. The ISL29030A is designed to run two transitions simultaneously: the A close transition and the als (or ir) transition. Please note that due to the conversion time, the user must let the ADC perform a full conversion of the register Prox_Data (wait 0.54ms) or Alsir_DT1/2 (wait) before reading the I2C. The time between als and prox transitions is arbitrary, ALS runs continuously to provide new data every 100ms. The proximity sensor operates continuously, and the conversion interval is determined by Prox_SLP (Register 1, Bits[6:4]). Ambient light and infrared sensing When register bit, ISL29030A is set to ambient light sensing alsir_mode=0, alr_en=1. Light wavelengths respond to ALS. ALS measurement mode (AS is the opposite of infrared measurement mode) default setting. When the part is programmed for infrared (IR) sensing (alsir_mode=1; als_en=1), the infrared light is converted to current and digitized by the same ALS ADC. The IR spectral result conversion is closely related to the amount of IR energy incident on the sensor, but it is unitless and referenced in digital counting. Proximity Sensing When Proximity Sensing is enabled (Prox_en=1), the external IR LED drives the 0.1ms LED driver through the built-in IR pin. The amplitude of the IR LED current depends on register 1 bit 3: prox_dr. If this bit is low, the load sees a 110ma current pulse. If this bit is high, the load on the IRDR will see a fixed 220ma current pulse.

When the infrared light from the LED reaches the object and is reflected back to the ISL29030A, the reflected infrared light is converted into electric current, as shown in the infrared spectral response. One conversion for an entire proximity measurement takes 0.54ms (including the 0.1ms LED drive time), and between proximity measurements is determined by Prox_SLP (sleep time) in register 1 bits 6:4. The average LED drive current consumption is given by Equation 1. A typical irdr scheme has 220ma amplitude pulses every 800ms, producing 28µA DC. Total Current Draw Total current draw is the sum of IDD and IIRDR. The IRA pins receive current, and the average irdr current can be calculated using Equation 1. IDD depends on voltage and operating mode, interrupt function The ISL29030A has a smart interrupt scheme designed to move some logic processing away from the intensive microcontroller. Independent light sensor ALS interrupt events (ALS_flags) are controlled by registers 5 through 7.

The user writes the high and low thresholds to the registers if the actual counts stored in registers 0x9 and 0xA are in the user programming window. User must write 0 to clear the sprite. Proximity interrupt events (Prox_flags) are controlled by High and Low thresholds (proximity and PROXYHT) in registers 3 and 4. When near data is measured, set the prox_flag greater than the user-specified high threshold number of times in a row (x; set by the user; see next paragraph). This is when the proximity data is below the low proximity threshold for x consecutive times, or when the user writes a "0" to the Prox_flag. Interrupt persistence is another option useful for both ALS and proximity measurements. Persistence requires a user-specified number (x) of consecutive interrupt flags preceded by an int. pin is driven low. Both ALS and Prox have their own independent interrupt persistence options. See als_prst and prox_prst bits in register 2. The final interrupt option is the ability to use the interrupt flags in register 2 bit 0 (int_ctrl). If the user wishes to change the state of the interrupt pin by the simultaneous occurrence of the ALS and PROX interrupts before this, the user sets this bit high. If the user wants the interrupt pin to go high at ALS or near the interrupt flag, the user leaves this bit with a default value of 0. Analog Output IALS Pin When ALS_en=1, the analog IALS output pin produces a current proportional to the digital count stored in register bits ALSELTA[11:0]. When als_en=0, the pin is in a high-impedance state. Compliance affects the voltage on IAL. ALS Range 1 Notes When the ALS count on measurement range 1 is higher than 1800 (alsir_mode=0, als_range=0, als_data > 1800), the user must switch to range 2 (change the ALS range bits from 0 to 1) to remeasure als the value of. This recommendation applies only to light incident on the sensor that is heavily IR-heavy, distorted by tinted glass, increasing the ratio from IR to visible light. VDD Power-Up and Power-Up Precautions When powering up, ensure that the VDD slew rate is 0.5V/ms or higher. After power-up, or if the power supply temporarily deviates from the factory specification (2.25V to 3.63V), Intersil recommends that the user write the following: 0x00 to register 0x01, 0x29 to register 0x0f, 0x00 to register 0x0e, 0x00 to register 0x0f. The user should then wait ~1ms or more before rewriting all registers to the desired values. If the user prefers the hardware reset method instead of writing to the test register, set vdd=0v for 1 second or more, power up again at the desired slew rate, and write the desired value of the register. Power down users can set shutdown in two ways. The first is that both set the Prox_en and Als_en bits in register 1 to 0. The second and easier way is to set all bits in register 1 to 0 (0x00). Calculating Lux In ALS mode, the ISL29030A ADC output code is directly proportional to Lux (see also IR Mode Bits). In Equation 2, ecalc is the calculated lux reading and represents the ADC code. The inserted constant α is determined by the range bits, the ALS range (register 0x1 bit 1) and is independent of the light source type. Noise Suppression Charge-balanced ADCs have good noise suppression at frequencies that are integer multiples of the slew rate. For example, the sum of unwanted signals from 0ms to k*16.66ms (k=1,2...ki) for 60hz AC is zero. Similarly, setting the integration time of the device to be a multiple of the integer periodic noise signal greatly increases the presence of noise in the light sensor output signal. The self-wall socket can output 60Hz or 50Hz, and the factory-set integration time is 100ms, which are two frequencies. Proximity Detection of Various Objects Proximity sensing relies on the amount of infrared reflected back from the object. A completely black object absorbs all light without reflecting photons. The ISL29030A is sensitive enough to detect black ESD foam, reflecting only 1% of IR. For biological objects, blonde hair is more reflective than brown hair, and customers may notice that skin tissue is much more reflective than hair.

Infrared penetrates the skin that is reflected or scattered back from the inside. Therefore, the proximity count peak at the contact decreases monotonically as the skin moves. The reflective properties of skin are different from those of paper. Typical application of the typical circuit ISL29030A. The ISL29030A I2C address is internally hardwired as 0B1000100. This device can be connected with other devices to I2C compatible devices on the system I2C bus. Soldering Precautions Convective heating is recommended for reflow soldering; direct infrared heating is not recommended. Plastic ODFN packages do not require custom reflow profiles and are eligible for +260°C. Standard reflow profile at +260°C maximum recommended. Recommended PCB footprint users must refer to TB477, "Surface Mount Components Optical Dual Flat Package Lead-Free (ODFN) Package Guidelines Layout Considerations Before Beginning Mounting the ODFN Product Board The ISL29030A is relatively insensitive to layout. Like other I2C devices, it is designed to Provides excellent performance even in noisy environments. To ensure optimum performance, keep the power supply and I2C lines as far away from all noise sources as possible, and place 0.1µf and 1µf decoupling capacitors near the power supply unit. The ALS sensor window layout should be Special care was taken to ensure uniform illumination of the sensor, "8 ld odfn sensor position profile - dimensions in mm". Shadows from window openings affecting uniform illumination can distort measurements.