ASR8600

PRELIMINARY

(March, 2015, Version 0.0)

4

AMIC Technology Corp.

CIE action spectrum

Wavelength (nm)

UV-B

UV-A

280

300

320

340

360

380

400

1e+00

1e-01

1e-02

1e-03

1e-04

Function Description

Light Sensor

The ASR8600 converts light intensity of ambient light (ALS),

Infrared light (IR) or Solar-UV to digital signal through I2C

interface by various photodiodes and ADC circuit. The I2C

interface follows Philip

drain active Interrupt pin.

The built-in ADC has 12 bits resolution. ASR8600 offers

user flexibility selection in integration time or gain for

different specific light detection range. If the light detection

is in general purpose, the user can use ASC (Auto Scale

Control) mode which can automatically adjust integration

time and gain to the best resolution for various light intensity.

The user has no need manually to set the integration time or

gain. With ASC mode, the output data is in dynamic range

of 16 bits. The Solar-UV sensing adopts only ASC mode

internally without manual mode option.

If the sensor will be under an overlay that is not 100%

transmissive to light source, the light data can be trimmed

back to the correct one. Please contact AMIC for more

information on adjusting these offset.

Proximity Sensor

Proximity sensing uses an external light source (generally

an infrared emitter) to emit light, which is then viewed by the

integrated light detector to measure the amount of reflected

light when an object is in the light path. The amount of light

detected from a reflected surface can then be used to

determine an object’s proximity to the sensor. The spectrum

of external LED/LD light source can be IR or Green selected

by customer using user command.

LED/LD

PROX

Sensor

Reflective Object

Overlay Glass

Optical Crosstalk

Background Light

When the proximity sensing is enabled, the external LED/LD

is driven by the built-in driver through the LDR pin. The

driving current of LED/LD is widely optional with range from

2.5mA to 300mA, and the pulse time is also changeable

from 0.1ms to 12.8ms. These optional settings are according

to the distance to be detected in application.

The ADC resolution of PS sensing is 8 bits with PS Offset

function to cancel the PS optical crosstalk from overlay

reflection. The PS offset value can be measured by PS

function without any object in front of the overlay, and set by

0xA5 user command of PS offset. The ASR8600 PS Offset

function can cancel the system internal reflection but still

keep full dynamic range of 8 bits (256 steps) of PS output,

so that the user is no need to modify the PS threshold

setting when applying PS Offset function.

ASR8600 also offers PS Auto Trim function if user requires

precise proximity distance to be detected in application. The

PS Auto Trim function can automatically set optimized gain

value in chip according to the preset object distance in front

of chip, and the value could be easily read out through user

command once the trim operation is done.

Solar Ultraviolet (Solar_UV) Index

The Solar_UV Index is a number linearly related to the

intensity of sunlight reaching the earth and is weighted

according to the CIE Erythemal Action Spectrum. This

weighting is a standardized measure of human skin's

response to different wavelengths of sunlight from UVB to

UVA. The UV Index has been standardized by the World

Health Organization and includes a simplified consumer UV

exposure level. ASR8600 can sense Solar_UV with 16 bits

output data, and user can divide it by 100 times magnitude

to get Solar_UV index.

CIE Erythemal Action Spectrum and UV Index Scale