TSL2771

LIGHT-TO-DIGITAL CONVERTER

with PROXIMITY SENSING

TAOS100B − FEBRUARY 2011

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The LUMENOLOGY

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Copyright

E 2011, TAOS Inc.

www.taosinc.com

Features

Detection in a Single Device

− Approximates Human Eye Response

− Programmable Analog Gain

− Programmable Integration Time

− Programmable Interrupt Function with

Upper and Lower Threshold

− Resolution Up to 16 Bits

− Very High Sensitivity — Operates Well

Behind Darkened Glass

− Up to 1,000,000:1 Dynamic Range

− Programmable Number of IR Pulses

− Programmable Current Sink for the IR

LED — No Limiting Resistor Needed

− Programmable Interrupt Function with

Upper and Lower Threshold

− Covers a 2000:1 Dynamic Range

− Programmable from 2.72 ms

to > 8 Seconds

− Wait State — 65

mA Typical Current

− Dedicated Interrupt Pin

Applications

Description

The TSL2771 family of devices provides both ambient light sensing (ALS) and proximity detection (when

coupled with an external IR LED). The ALS approximates human eye response to light intensity under a variety

of lighting conditions and through a variety of attenuation materials. The proximity detection feature allows a

large dynamic range of operation for use in short distance detection behind dark glass such as in a cell phone

or for longer distance measurements for applications such as presence detection for monitors or laptops. The

programmable proximity detection enables continuous measurements across the entire range. In addition, an

internal state machine provides the ability to put the device into a low power mode in between ALS and proximity

measurements providing very low average power consumption.

While useful for general purpose light sensing, the device is particularly useful for display management with the

purpose of extending battery life and providing optimum viewing in diverse lighting conditions. Display panel

and keyboard backlighting can account for up to 30 to 40 percent of total platform power. The ALS features are

ideal for use in tablets, notebook PCs, LCD monitors, flat-panel televisions, and cell phones.

The proximity function is targeted specifically towards cell phone, LCD monitor, laptop, and flat-panel television

applications. In cell phones, the proximity detection can detect when the user positions the phone close to their

ear. The device is fast enough to provide proximity information at a high repetition rate needed when answering

a phone call. It can also detect both close and far distances so the application can implement more complex

algorithms to provide a more robust interface. In laptop or monitor applications, the product is sensitive enough

to determine whether a user is in front of the laptop using the keyboard or away from the desk. This provides

both improved green power saving capability and the added security to lock the computer when the user is not

present.

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Texas Advanced Optoelectronic Solutions Inc.

1001 Klein Road

S Suite 300 S Plano, TX 75074 S (972) 673-0759

PACKAGE FN

DUAL FLAT NO-LEAD

(TOP VIEW)

SCL 2

GND 3

6 SDA

5 INT

4 LDR

Package Image Not Actual Size