TSL27711FN TAOS, TSL27711FN Datasheet - Page 8

• Manufacturer Part Number: TSL27711FN
• Description: Light to Digital Converters Light to Digital w/Proximity
• Manufacturer: TAOS

Specifications of TSL27711FN

• Data Bus Width: 16 bit
• Peak Wavelength: 640 nm, 850 nm
• Maximum Operating Frequency: 795 KHz
• Operating Supply Voltage: 2.4 V to 3.6 V
• Operating Current: 175 uA
• Maximum Operating Temperature: + 70 C
• Minimum Operating Temperature: - 30 C
• Interface Type: I2C
• Maximum Fall Time: 300 ns
• Maximum Rise Time: 300 ns
• Mounting Style: SMD/SMT
• Resolution: 16 bit
• Package / Case: DFN-6
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

TSL2771
LIGHT-TO-DIGITAL CONVERTER
with PROXIMITY SENSING
TAOS100A − FEBRUARY 2010
System State Machine
Clear and IR Diodes
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Copyright E 2010, TAOS Inc.
The TSL2771 provides control of ALS, proximity detection, and power management functionality through an
internal state machine (Figure 6). After a power-on-reset, the device is in the sleep mode. As soon as the PON
bit is set, the device will move to the start state. It will then continue through the Prox, Wait, and ALS states. If
these states are enabled, the device will execute each function. If the PON bit is set to 0, the state machine will
continue until all conversions are completed and then go into a low power sleep mode.
NOTE: In this document, the nomenclature uses the bit field name in italics followed by the register number and
bit number to allow the user to easily identify the register and bit that controls the function. For example, the
power on (PON) is in register 0, bit 0. This is represented as PON (r0:b0).
Conventional silicon detectors respond strongly to infrared light, which the human eye does not see. This can
lead to significant error when the infrared content of the ambient light is high (such as with incandescent lighting)
due to the difference between the silicon detector response and the brightness perceived by the human eye.
This problem is overcome in the TSL2771 through the use of two photodiodes. One of the photodiodes, referred
to as the clear channel, is sensitive to both visible and infrared light while the second photodiode is sensitive
primarily to infrared light. Two integrating ADCs convert the photodiode currents to digital outputs. The IRDATA
digital value is used to compensate for the effect of the infrared component of light on the CDATA (clear) digital
value. The ADC digital outputs from the two channels are used in a formula to obtain a value that approximates
the human eye response in units of lux.
Figure 6. Simplified State Diagram
PON = 1 (r 0:b0)
Prox
PRINCIPLES OF OPERATION
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Sleep
Start
Wait
PON = 0 (r 0:b0)
ALS
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