TSL2571
Light-to-Digital Converter
General Description
The TSL2571 family of devices provides ambient light sensing
(ALS) that approximates human eye response to light intensity
under a variety of lighting conditions and through a variety of
attenuation materials. 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 notebook PCs, LCD monitors, flat-panel
televisions, and cell phones.
Ordering Information
and
Content Guide
appear at end of
datasheet.
Key Benefits & Features
The benefits and features of TSL2571, Light-to-Digital
Converter are listed below:
Figure 1:
Added Value Of Using TSL2571
Benefits
•
Enables Operation in IR Light Environments
•
Enables Dark Room to High Lux Sunlight
Operation
•
Digital Interface is Less Susceptible to
Noise
•
Enables Low Standby Power Consumption
•
Reduces Board Space Requirements while
Simplifying Designs
Features
•
Patented Dual-Diode Architecture
•
1M:1 Dynamic Range
•
I
2
C Digital Interface
•
2.5μA Quiescent Current (Sleep Mode)
•
Available in 2mm x 2mm Dual Flat No-Lead (FN) Packages
•
Ambient Light Sensing (ALS)
• 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
ams Datasheet
[v1-01] 2018-Mar-27
Page 1
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TSL2571 −
General Description
•
Programmable Wait Timer
• Programmable from 2.72 ms to > 8 Seconds
• Wait State — 65μA Typical Current
•
I²C Interface Compatible
• Up to 400 kHz (I²C Fast Mode)
• Dedicated Interrupt Pin
•
Small 2 mm x 2 mm ODFN Package
•
Sleep Mode — 2.5μA Typical Current
Applications
TSL2571, Light-to-Digital Converter is ideal for:
•
Display Management
•
Backlight Control
•
Portable Device Power Optimization
•
Cell Phones, PDA, GPS
•
Notebooks and Monitors
•
LCD TVs
Functional Block Diagram
The functional blocks of this device are shown below:
Figure 2:
TSL2571 Block Diagram
GND
Interrupt
Wait Control
Upper Limit
CH0
ADC
CH0
CH1
ADC
CH1
CH1
Data
CH0
Data
Lower Limit
INT
V
DD
ALS Control
I
2
C Interface
SCL
SDA
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ams Datasheet
[v1-01] 2018-Mar-27
TSL2571 −
Pin Assignments
Pin Assignments
Figure 3:
Package FN Dual Flat No-Lead (Top View)
V
DD
1
SCL 2
GND 3
6 SDA
5 INT
4 NC
Figure 4:
Terminal Functions
Terminal
Type
Name
V
DD
SCL
GND
NC
INT
SDA
Description
No
1
2
3
4
5
6
O
I/O
I
Supply voltage.
I²C serial clock input terminal — clock signal for I²C serial data.
Power supply ground. All voltages are referenced to GND.
Do not connect.
Interrupt — open drain (active low).
I²C serial data I/O terminal — serial data I/O for I²C .
ams Datasheet
[v1-01] 2018-Mar-27
Page 3
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TSL2571 −
Detailed Description
Detailed Description
The TSL2571 light-to-digital device includes on-chip
photodiodes, integrating amplifiers, ADCs, accumulators,
clocks, buffers, comparators, a state machine, and an I²C
interface. The device combines one photodiode (CH0), which is
responsive to both visible and infrared light, and one
photodiode (CH1), which is responsive primarily to infrared
light. Two integrating ADCs simultaneously convert the
amplified photodiode currents into a digital value providing up
to 16 bits of resolution. Upon completion of the conversion
cycle, the conversion result is transferred to the data registers.
This digital output can be read by a microprocessor through
which the illuminance (ambient light level) in lux is derived
using an empirical formula to approximate the human eye
response.
Communication to the device is accomplished through a fast
(up to 400 kHz), two-wire I²C serial bus for easy connection to
a microcontroller or embedded controller. The digital output of
the device is inherently more immune to noise when compared
to an analog interface.
The device provides a separate pin for level-style interrupts.
When interrupts are enabled and a pre-set value is exceeded,
the interrupt pin is asserted and remains asserted until cleared
by the controlling firmware. The interrupt feature simplifies and
improves system efficiency by eliminating the need to poll a
sensor for a light intensity value. An interrupt is generated when
the value of an ALS conversion exceeds either an upper or lower
threshold. In addition, a programmable interrupt persistence
feature allows the user to determine how many consecutive
exceeded thresholds are necessary to trigger an interrupt.
Interrupt thresholds and persistence settings are configured
independently.
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ams Datasheet
[v1-01] 2018-Mar-27
TSL2571 −
Absolute Maximum Ratings
Absolute Maximum Ratings
Stresses beyond those listed under
Absolute Maximum Ratings
may cause permanent damage to the device. These are stress
ratings only, and functional operation of the device at these or
any other conditions beyond those indicated under
Recommended Operating Conditions
is not implied. Exposure
to absolute-maximum-rated conditions for extended periods
may affect device reliability.
Figure 5:
Absolute Maximum Ratings Over Operating Free-Air Temperature Range (unless otherwise noted)
Symbol
V
DD(1)
V
O
I
O
T
STRG
ESD
HBM
Note(s):
1. All voltages are with respect to GND.
Parameter
Supply voltage
Digital output voltage range
Digital Output current
Storage temperature range
ESD tolerance, human body model
Min
Max
3.8
Units
V
V
mA
°C
V
-0.5
-1
-40
±2000
3.8
+20
85
ams Datasheet
[v1-01] 2018-Mar-27
Page 5
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