TMD2771

TAOS Inc.
is now
ams AG
The technical content of this TAOS datasheet is still valid.
Contact information:
Headquarters:
ams AG
Tobelbaderstrasse 30
8141 Unterpremstaetten, Austria
Tel: +43 (0) 3136 500 0
e-Mail: [email protected]
Please visit our website at www.ams.com
TMD2771
DIGITAL ALS
and PROXIMITY MODULE
r
r
TAOS143B − SEPTEMBER 2012
Features
PACKAGE
MODULE−8
(TOP VIEW)
D Ambient Light Sensing, Proximity
D Ambient Light Sensing (ALS)
−
−
−
−
D Proximity Detection
Calibrated to 100-mm Detection
Eliminates Factory Calibration of Prox
Programmable Number of IR Pulses
Programmable Current Sink for the IR
LED — No Limiting Resistor Needed
− Programmable Interrupt Function with
Upper and Lower Threshold
D Programmable Wait Timer
− Wait State — 65 mA Typical Current
− Programmable from 2.72 ms
to > 8 Seconds
Description
SCL 2
7 INT
GND 3
6 LDR
LEDA 4
5 LEDK
Package Drawing is Not to Scale
D I2C Interface Compatible
D
D
D
− Up to 400 kHz (I2C Fast Mode)
Dedicated Interrupt Pin
3.94 mm 2.4 mm 1.35 mm Package
Sleep Mode — 2.5 mA Typical
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−
−
−
−
8 SDA
lv
Approximates Human Eye Response
Programmable Analog Gain
Programmable Integration Time
Programmable Interrupt Function with
Upper and Lower Threshold
− Up to 16 Bits Resolution
− Very High Sensitivity — Operates Behind
Darkened Glass
− Up to 1,000,000:1 Dynamic Range
VDD 1
al
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Detection, and IR LED in a Single Optical
Module
Applications
D
D
D
D
D
Cell Phone Backlight Dimming
Cell Phone Touch Screen Disable
Notebook/Monitor Security
Automatic Speakerphone Enable
Automatic Menu Popup
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The TMD2771 family of devices provides digital ambient light sensing (ALS), a complete proximity detection
system, and digital interface logic in a single 8-pin package. The proximity detector includes a digital proximity
sensor, LED driver, and IR LED, which are trimmed to eliminate the need for end-equipment calibration due to
component variations. Excellent background light rejection allows the device to operate in environments from
sunlight to dark rooms. The wide dynamic range allows for operation in short distance detection such as a cell
phone (behind dark glass). 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.
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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.
Te
ch
The proximity function specifically targets near-field proximity 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. This provides both improved
green power saving capability and the added security to lock the computer when the user is not present. The
addition of the micro-optics lenses within the device, provide highly efficient transmission and reception of
infrared energy, which lowers overall power dissipation.
The LUMENOLOGY r Company
Copyright E 2012, TAOS Inc.
r
Texas Advanced Optoelectronic Solutions Inc.
1001 Klein Road S Suite 300 S Plano, TX 75074 S (972)
r 673-0759
www.taosinc.com
1
TMD2771
DIGITAL ALS
and PROXIMITY MODULE
TAOS143B − SEPTEMBER 2012
Functional Block Diagram
VDD
Interrupt
IR LED Constant
Current Sink
Prox Control
Prox
Integration
Prox
ADC
INT
Upper Limit
Prox
Data
Lower Limit
SCL
Upper Limit
CH0
ADC
CH0
Data
LEDK
ALS Control
Lower Limit
Channel 0
CH1
Data
SDA
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CH1
ADC
lv
Wait Control
I2C Interface
LEDA
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LDR
Channel 1
GND
Detailed Description
The light-to-digital device provides on-chip photodiodes, integrating amplifiers, ADCs, accumulators, clocks,
buffers, comparators, a state machine, and an I2C interface. Each device combines one photodiode (CH0),
which is responsive to both visible and infrared light, and a second photodiode (CH1), which is responsive
primarily to infrared light. Two integrating ADCs simultaneously convert the amplified photodiode currents to
a digital value providing up to 16-bits of resolution. Upon completion of the conversion cycle, the conversion
result is transferred to the Ch0 and Ch1 data registers. This digital output can be read by a microprocessor
where the luminance (ambient light level in lux) is derived using an empirical formula to approximate the human
eye response.
ni
ca
A fully integrated proximity detection solution is provided with an 850-nm IR LED, LED driver circuit, and
proximity detection engine. An internal LED driver (LDR) pin, is connected to the LED cathode (LEDK) to provide
a factory calibrated proximity of 100 mm, ± 20 mm. This is accomplished with a proprietary current calibration
technique that accounts for all variances in silicon, optics, package, and most important, IR LED output power.
This eliminates or greatly reduces the need for factory calibration that is required for most discrete proximity
sensor solutions. While the device is factory calibrated at a given pulse count, the number of proximity LED
pulses can be programmed from 1 to 255 pulses, which allows different proximity distances to be achieved.
Each pulse has a 16 μs period with a 7.2 μs on time.
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Communication with 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 photodiode interface.
Te
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 or proximity value. An interrupt is generated when the value of an ALS or proximity 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 for both ALS and proximity.
Copyright E 2012, TAOS Inc.
The LUMENOLOGY r Company
r
r
2
www.taosinc.com
TMD2771
DIGITAL ALS
and PROXIMITY MODULE
TAOS143B − SEPTEMBER 2012
Terminal Functions
TERMINAL
NAME
NO.
TYPE
DESCRIPTION
3
Power supply ground. All voltages are referenced to GND.
INT
7
O
Interrupt — open drain.
LDR
6
I
LED driver input for proximity IR LED, constant current source LED driver.
LEDA
4
I
LED anode.
LEDK
5
O
LED cathode. Connect to LDR pin when using internal LED driver circuit.
SCL
2
I
I2C serial clock input terminal — clock signal for I2C serial data.
SDA
8
I/O
VDD
1
al
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GND
I2C serial data I/O terminal — serial data I/O for I2C .
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Supply voltage.
Available Options
ADDRESS
0x39
PACKAGE − LEADS
INTERFACE DESCRIPTION
ORDERING NUMBER
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DEVICE
TMD27711
TMD27713
0x39
Module−8
I2C Vbus = VDD Interface
TMD27711
Module−8
I2C
TMD27713
Vbus = 1.8 V Interface
Absolute Maximum Ratings over operating free-air temperature range (unless otherwise noted)†
Supply voltage, VDD (see Note 1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.8 V
Digital output voltage range, VO . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . −0.5 V to 3.8 V
Digital output current, IO . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . −1 mA to 20 mA
Analog voltage range, LDR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . −0.5 V to 3.8 V
Storage temperature range, Tstg . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . −40°C to 85°C
ESD tolerance, human body model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2000 V
†
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.
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NOTE 1: All voltages are with respect to GND.
Recommended Operating Conditions
NOM
MAX
2.6
3
3.6
−3
3
%
Operating free-air temperature, TA (Note 2)
−30
85
°C
UNIT
V
ch
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MIN
Supply voltage, VDD
Supply voltage accuracy, VDD total error including transients
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NOTE 2: While the device is operational across the temperature range, functionality will vary with temperature. Specifications are stated only
at 25°C unless otherwise noted.
The LUMENOLOGY r Company
Copyright E 2012, TAOS Inc.
r
r
www.taosinc.com
3
TMD2771
DIGITAL ALS
and PROXIMITY MODULE
TAOS143B − SEPTEMBER 2012
Operating Characteristics, VDD = 3 V, TA = 25C (unless otherwise noted)
PARAMETER
TEST CONDITIONS
MIN
Active — ATIME = 100 ms
IDD
Supply current
INT SDA output low voltage
INT,
I LEAK
Leakage current, SDA, SCL, INT pins
I LEAK
Leakage current, LDR pin
VIH
SCL SDA input high voltage
SCL,
VIL
SCL SDA input low voltage
SCL,
250
Wait mode
65
Sleep mode
2.5
Supply current — LDR pulse On
VOL
MAX
175
μA
4
3
mA
3 mA sink current
0
0.4
6 mA sink current
0
0.6
−5
TMD27711
0.7 VDD
TMD27713
1.25
V
5
μA
10
μA
V
0.3 VDD
lv
TMD27711
UNIT
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IDD
TYP
0.54
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TMD27713
V
ALS Characteristics, VDD = 3 V, TA = 25C, AGAIN = 16×, AEN = 1 (unless otherwise noted) (Note 1)
PARAMETER
TEST CONDITIONS
Dark ALS ADC count value
Ee = 0, AGAIN = 120×,
ATIME = 0xDB (100 ms)
ALS ADC integration time step size
ATIME = 0xFF
CHANNEL
MIN
TYP
MAX
CH0
0
1
5
CH1
0
1
5
2.58
2.72
ALS ADC Number of integration steps
ADC counts per step
ADC count value
1
Irradiance responsivity
1024
counts
0
65535
counts
μW/cm2,
CH0
4000
CH1
CH0
5000
6000
790
4000
CH1
5000
2800
10 8
10.8
15 8
15.8
20.8
20 8
λp = 850 nm
nm, ATIME = 0xF6 (27 ms) See note 3
3.
41
56
68
λp = 625 nm, ATIME = 0xF6 (27 ms)
See note 2.
CH0
82.6
CH1
13.1
λp = 850 nm, ATIME = 0xF6 (27 ms)
See note 3.
CH0
60.5
CH1
%
counts/
(μW/
cm2)
33.9
8×
−10
10
16×
−10
10
10
−10
10
120×
counts
6000
λp = 625 nm
nm, ATIME = 0xF6 (27 ms) See note 2
2.
ni
G i scaling,
Gain
li
relative
l ti to
t 1× gain
i
setting
ms
steps
0
ca
Re
2.9
256
ATIME = 0xC0
λp = 850 nm, Ee = 82.7 μW/cm2,
ATIME = 0xF6 (27 ms)
See note 3.
ALS ADC count value ratio: CH1/CH0
counts
ATIME = 0xFF
λp = 625 nm, Ee = 60.5
ATIME = 0xF6 (27 ms)
See note 2.
ALS ADC count value
UNIT
%
Te
ch
NOTES: 1. Optical measurements are made using small-angle incident radiation from light-emitting diode optical sources. Visible 625 nm LEDs
and infrared 850 nm LEDs are used for final product testing for compatibility with high-volume production.
2. The 625 nm irradiance Ee is supplied by an AlInGaP light-emitting diode with the following typical characteristics: peak wavelength
λp = 625 nm and spectral halfwidth Δλ½ = 20 nm.
3. The 850 nm irradiance Ee is supplied by a GaAs light-emitting diode with the following typical characteristics: peak wavelength
λp = 850 nm and spectral halfwidth Δλ½ = 42 nm.
Copyright E 2012, TAOS Inc.
The LUMENOLOGY r Company
r
r
4
www.taosinc.com
TMD2771
DIGITAL ALS
and PROXIMITY MODULE
TAOS143B − SEPTEMBER 2012
Proximity Characteristics, VDD = VLEDA = 3 V, TA = 25C, PEN = 1 (unless otherwise noted)
PARAMETER
MIN
Supply current — LDR pulse on
TYP
MAX
3
ADC conversion time step size
PTIME = 0xFF
ADC counts per step
mA
2.72
ADC number of integration steps
PTIME = 0xFF
Proximity IR LED pulse count
ms
1
256
steps
0
1023
counts
0
255
pulses
Proximity pulse period
μs
16.3
PDRIVE = 0 (100% current level)
UNIT
75
PDRIVE = 1 (50% current level)
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IDD
TEST CONDITIONS
100
150
50
ILEDA
LED current @ V 600 mV,
mV LDR pin sink (Note 1)
TLDR
On time per pulse
PDRIVE = 1
Proximity response, no target (offset)
PDRIVE = 0, PPULSE = 8 (Note 2)
Prox count, 100-mm target (Note 3)
73 mm × 83 mm, 90% reflective Kodak
Gray Card,
PPULSE = 8, PDRIVE = 0, PTIME =
0xFF (Note 4)
PDRIVE = 2 (25% current level)
mA
25
12.5
7.2
μs
100
counts
lv
PDRIVE = 3 (12.5% current level)
520
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414
624
counts
NOTES: 1. Value is factory-adjusted to meet the Prox count specification. Considerable variation (relative to the typical value) is possible after
adjustment.
2. No reflective surface above the module. Proximity offset varies with power supply characteristics and noise.
3. ILEDA is factory calibrated to achieve this specification. Offset and crosstalk directly sum with this value and is system dependent.
4. No glass or aperture above the module. Tested value is the average of 5 consecutive readings.
5. These parameters are ensured by design and characterization and are not 100% tested.
6. Proximity test was done using the following circuit. See the Application Information: Hardware section for recommended
application circuit.
VDD
VDD
4
1
TMD2771
1 mF
GND
3
5
6
LEDA
LEDK
LDR
1 mF
22 mF
IR LED Characteristics, VDD = 3 V, TA = 25C
TEST CONDITIONS
MIN
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PARAMETER
MAX
1.4
1.5
UNIT
Forward Voltage
VR
Reverse Voltage
PO
Radiant Power
λp
Peak Wavelength
IF = 20 mA
850
nm
Δλ
Spectral Radiation Bandwidth
IF = 20 mA
40
nm
TR
Optical Rise Time
IF = 100 mA, TW = 125 ns, duty cycle = 25%
20
40
ns
Optical Fall Time
IF = 100 mA, TW = 125 ns, duty cycle = 25%
20
40
ns
TYP
MAX
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VF
TF
IF = 20 mA
TYP
IR = 10 μA
5
IF = 20 mA
4.5
V
V
mW
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Wait Characteristics, VDD = 3 V, TA = 25C, WEN = 1 (unless otherwise noted)
PARAMETER
Wait step size
TEST CONDITIONS
MIN
WTIME = 0xFF
2.72
Wait number of integration steps
The LUMENOLOGY r Company
1
UNIT
2.9
ms
256
steps
Copyright E 2012, TAOS Inc.
r
r
www.taosinc.com
5
TMD2771
DIGITAL ALS
and PROXIMITY MODULE
TAOS143B − SEPTEMBER 2012
AC Electrical Characteristics, VDD = 3 V, TA = 25C (unless otherwise noted)
PARAMETER†
(I2C
TEST CONDITIONS
MIN
UNIT
400
kHz
Clock frequency
t(BUF)
Bus free time between start and stop condition
1.3
μs
t(HDSTA)
Hold time after (repeated) start condition. After
this period, the first clock is generated.
0.6
μs
t(SUSTA)
Repeated start condition setup time
0.6
μs
t(SUSTO)
Stop condition setup time
0.6
μs
t(HDDAT)
Data hold time
t(SUDAT)
Data setup time
100
t(LOW)
SCL clock low period
1.3
t(HIGH)
SCL clock high period
0.6
tF
Clock/data fall time
tR
Clock/data rise time
Ci
Input pin capacitance
μs
ns
μs
μs
lv
0
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0
MAX
f(SCL)
300
ns
300
ns
10
pF
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†
only)
TYP
Specified by design and characterization; not production tested.
PARAMETER MEASUREMENT INFORMATION
t(LOW)
VIH
SCL
VIL
t(R)
t(F)
t(HDSTA)
t(BUF)
t(HIGH)
t(HDDAT)
t(SUSTA)
t(SUSTO)
t(SUDAT)
VIH
SDA
VIL
S
S
P
Start
Condition
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P
Stop
Condition
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Figure 1. Timing Diagrams
Copyright E 2012, TAOS Inc.
The LUMENOLOGY r Company
r
r
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TMD2771
DIGITAL ALS
and PROXIMITY MODULE
TAOS143B − SEPTEMBER 2012
TYPICAL CHARACTERISTICS
LDR OUTPUT COMPLIANCE
SPECTRAL RESPONSIVITY
112.5
1
Ch 0
al
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100
0.8
0.6
0.4
Ch 1
75
62.5
50 mA
50
lv
Load Current — mA
87.5
37.5
25 mA
25
0.2
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Normalized Responsivity
100 mA
12.5 mA
12.5
0
300
400
500
600
700
800
0
0
900 1000 1100
0.3
λ − Wavelength − nm
Figure 2
108%
0.9
1.2
Figure 3
NORMALIZED RESPONSIVITY
vs.
ANGULAR DISPLACEMENT
NORMALIZED IDD
vs.
VDD and TEMPERATURE
110%
0.6
VOL − Output Low Voltage − V
1.0
25C
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50C
102%
100%
96%
ni
0C
98%
Optical Axis
104%
Normalized Responsivity
0.8
106%
ch
IDD Normalized @ 3 V, 25C
75C
0.6
0.4
0.2
94%
2.8
Te
92%
2.7
2.9
3
3.1
3.2
3.3
VDD — V
0
−90
-Q
Figure 4
The LUMENOLOGY r Company
+Q
−60
−30
0
30
60
Q − Angular Displacement − °
90
Figure 5
Copyright E 2012, TAOS Inc.
r
r
www.taosinc.com
7
TMD2771
DIGITAL ALS
and PROXIMITY MODULE
TAOS143B − SEPTEMBER 2012
PRINCIPLES OF OPERATION
System State Machine
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The device provides control of ALS, proximity detection and power management functionality through an
internal state machine. 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 a 0, the state machine will continue
until all conversions are completed and then go into a low-power sleep mode.
Sleep
PON = 1 (r 0:b0)
PON = 0 (r 0:b0)
Prox
lv
Start
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ALS
Wait
Figure 6. Simplified State Diagram
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).
Photodiodes
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.
Te
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This problem is overcome through the use of two photodiodes. The Channel 0 photodiode is sensitive to both
visible and infrared light, while the Channel 1 photodiode is sensitive primarily to infrared light. Two integrating
ADCs convert the photodiode currents to digital outputs. 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.
Copyright E 2012, TAOS Inc.
The LUMENOLOGY r Company
r
r
8
www.taosinc.com
TMD2771
DIGITAL ALS
and PROXIMITY MODULE
TAOS143B − SEPTEMBER 2012
ALS Operation
ATIME(r 1)
2.72 ms to 700 ms
CH0
ADC
C0DATAH(r 0x15), C0DATA(r 0x14)
ALS Control
CH1
ADC
CH1
Data
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Channel 0
Visible and IR
CH0
Data
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The ALS engine contains ALS gain control (AGAIN) and two integrating analog-to-digital converters (ADC)
for the two photodiodes. The ALS integration time (ATIME) impacts both the resolution and the sensitivity of the
ALS reading. Integration of both channels occurs simultaneously and upon completion of the conversion cycle,
the results are transferred to the data registers (C0DATA and C1DATA). This data is also referred to as channel
count. The transfers are double-buffered to ensure data integrity.
C1DATAH(r 0x17), C1DATA(r 0x16)
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Channel 1
IR Only
AGAIN(r 0x0F, b1:0)
1, 8, 16, 120 Gain
Figure 7. ALS Operation
The registers for programming the integration and wait times are a 2’s compliment values. The actual time can
be calculated as follows:
ATIME = 256 − Integration Time / 2.72 ms
Inversely, the time can be calculated from the register value as follows:
Integration Time = 2.72 ms × (256 − ATIME)
In order to reject 50/60-Hz ripple strongly present in fluorescent lighting, the integration time needs to
be programmed in multiples of 10 / 8.3 ms or the half cycle time. Both frequencies can be rejected with a
programmed value of 50 ms (ATIME = 0xED) or multiples of 50 ms (i.e. 100, 150, 200, 400, 700).
The registers for programming the AGAIN hold a two-bit value representing a gain of 1×, 8×, 16×, or 120×. The
gain, in terms of amount of gain, will be represented by the value AGAINx, i.e. AGAINx = 1, 8, 16, or 120.
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Lux Equation
ch
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The lux calculation is a function of CH0 channel count (C0DATA), CH1 channel count (C1DATA), ALS Gain
(AGAINx), and ALS integration time in milliseconds (ATIME_ms). For a device in open air with no aperture or
glass/plastic above the device, lux can be calculated using the following. If an aperture, glass/plastic, or a light
pipe attenuates the light equally across the spectrum (300 nm to 1100 nm), then a scaling factor can be used
(referred to as GA in the equation below). For open air with no aperture, GA = 1. If it is not spectrally flat, then
a custom lux equation with new coefficients should be generated. (See TAOS application note.)
Te
Counts per Lux (CPL) needs to be calculated only when ATIME or AGAIN is changed, otherwise it remains a
constant. The first segment of the equation (Lux1) covers fluorescent and incandescent light. The second
segment (Lux2) covers dimmed incandescent light. The final lux is the maximum of Lux1, Lux2, or 0.
CPL = (ATIME_ms × AGAINx) / (GA × 24)
Lux1 = (C0DATA − 2 × C1DATA) / CPL
Lux2 = (0.6 × C0DATA − C1DATA) / CPL
Lux = MAX(Lux1, Lux2, 0)
The LUMENOLOGY r Company
Copyright E 2012, TAOS Inc.
r
r
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9
TMD2771
DIGITAL ALS
and PROXIMITY MODULE
TAOS143B − SEPTEMBER 2012
Proximity Detection
Proximity detection is accomplished by measuring the amount of IR energy, from the internal IR LED, reflected
off an object to determine its distance. The internal proximity IR LED is driven by the integrated proximity LED
current driver as shown in Figure 8.
IR
LED
PPULSE(r0x0E)
PDRIVE(r0x0F, b7:6)
LEDK
PTIME(r0x02)
Prox LED
Current Driver
LDR
Prox Control
Prox
Data
PDATAH(r0x019)
PDATAL(r0x018)
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Prox
ADC
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Prox
Integration
PDIODE(r0x0F, b5:4)
Object
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LEDA
CH1
CH0
Background Energy
Figure 8. Proximity Detection
The LED current driver provides a regulated current sink on the LDR terminal that eliminates the need for an
external current limiting resistor. The PDRIVE register setting sets the sink current to 100%, 50%, 25%, or 12.5%
of the factory trimmed full scale current.
Referring to the Detailed State Machine figure, the LED current driver pulses the IR LED as shown in Figure 9
during the Prox Accum state. Figure 9 also illustrates that the LED On pulse has a fixed width of 7.3 μs and
period of 16.0 μs. So, in addition to setting the proximity drive current, 1 to 255 proximity pulses (PPULSE) can
be programmed. When deciding on the number of proximity pulses, keep in mind that the signal increases
proportionally to PPULSE, while noise increases by the square root of PPULSE.
ca
Reflected IR LED +
Background Energy
LED On
Background
Energy
LED Off
Te
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ni
7.3 ms
16.0 ms
IR LED Pulses
Figure 9. Proximity LED Current Driver Waveform
Figure 8 illustrates light rays emitting from the internal IR LED, reflecting off an object, and being absorbed by
the CH0 and CH1 photodiodes. The proximity diode selector (PDIODE) determines which of the two
photodiodes is used for a given proximity measurement. Note that neither photodiode is selected when the
device first powers up, so PDIODE must be set for proximity detection to work.
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TMD2771
DIGITAL ALS
and PROXIMITY MODULE
TAOS143B − SEPTEMBER 2012
Referring again to Figure 9, the reflected IR LED and the background energy is integrated during the LED On
time, then during the LED Off time, the integrated background energy is subtracted from the LED On time
energy, leaving the IR LED energy to accumulate from pulse to pulse.
al
id
After the programmed number of proximity pulses have been generated, the proximity ADC converts and scales
the proximity measurement to a 16-bit value, then stores the result in two 8-bit proximity data (PDATAx)
registers. ADC scaling is controlled by the proximity ADC conversion time (PTIME) which is programmable from
1 to 256 2.73-ms time units. However, depending on the application, scaling the proximity data will equally scale
any accumulated noise. Therefore, in general, it is recommended to leave PTIME at the default value of one
2.73-ms ADC conversion time (0xFF).
For additional information on using the proximity detection function behind glass and for optical system design
guidance, please see available TAOS application notes.
lv
Optical Design Considerations
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The TMD2771 device simplifies the optical system design by integrating an IR LED into the package, and also
by providing an effective barrier between the LED and proximity sensor. In addition the package contains
integrated lenses and apertures over both the LED and the sensor, which significantly extends the maximum
proximity detection distance and helps to reduce optical crosstalk.
Te
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Although the package integrates an optical barrier between the IR LED and detector, placing the device behind
a cover glass potentially provides another significant path for IR light to reach the detector, via reflection from
the inside and outside faces of the cover glass. Because it is cost prohibitive to use anti-reflection coatings
on the glass, the faces of the glass will reflect significantly (typically on the order of 4% of the light), and it is crucial
that the system be designed so that this reflected light cannot find an efficient path back to the optical detector.
See TAOS Application Note DN28: Proximity Detection Behind Glass for a detailed discussion of optical design
considerations.
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TMD2771
DIGITAL ALS
and PROXIMITY MODULE
TAOS143B − SEPTEMBER 2012
Interrupts
The interrupt feature simplifies and improves system efficiency by eliminating the need to poll the sensor for
a light intensity or proximity value. The interrupt mode is determined by the PIEN or AIEN field in the ENABLE
register.
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Four 16-bit-wide interrupt threshold registers allow the user to define thresholds above and below a desired light
level. For ALS, an interrupt can be generated when the ALS C0DATA exceeds the upper threshold value (AIHTx)
or falls below the lower threshold (AILTx). For proximity, an interrupt can be generated when the proximity data
(PDATA) exceeds the upper threshold value (PIHTx) or falls below the lower threshold (PILTx).
Prox
ADC
PIHTH(r 0x0B), PIHTL(r 0x0A8)
PPERS(r 0x0C, b7:4)
Upper Limit
Prox Persistence
Prox
Data
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Prox
Integration
lv
To further control when an interrupt occurs, the device provides an interrupt persistence feature. This feature
allows the user to specify a number of conversion cycles for which an event exceeding the ALS interrupt
threshold must persist (APERS) or the proximity interrupt threshold must persist (PPERS) before actually
generating an interrupt. Refer to the register descriptions for details on the length of the persistence.
Lower Limit
PILTH(r 09), PILTL(r 08)
AIHTH(r 07), AIHTL(r 06)
Upper Limit
CH0
ADC
APERS(r 0x0C, b3:0)
ALS Persistence
CH0
Data
Lower Limit
Channel 0
Visible and IR
CH1
ADC
CH1
Data
AILTH(r 05), AILTL(r 04)
Channel 1
IR Only
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Figure 10. Programmable Interrupt
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TMD2771
DIGITAL ALS
and PROXIMITY MODULE
TAOS143B − SEPTEMBER 2012
State Diagram
Figure 11 shows a more detailed flow for the state machine. The device starts in the sleep mode. The PON bit
is written to enable the device. A 2.72-ms delay will occur before entering the start state. If the PEN bit is set,
the state machine will step through the proximity states of proximity accumulate and then proximity ADC
conversion. As soon as the conversion is complete, the state machine will move to the following state.
al
id
If the WEN bit is set, the state machine will then cycle through the wait state. If the WLONG bit is set, the wait
cycles are extended by 12× over normal operation. When the wait counter terminates, the state machine will
step to the ALS state.
The AEN should always be set, even in proximity-only operation. In this case, a minimum of 1 integration time
step should be programmed. The ALS state machine will continue until it reaches the terminal count at which
point the data will be latched in the ALS register and the interrupt set, if enabled.
Up to 255 steps
Step: 2.72 ms
Time: 2.72 ms − 696 ms
120 Hz Minimum − 8 ms
100 Hz Minimum − 10 ms
lv
Up to 255 LED Pulses
Pulse Frequency: 62.5 kHz
Time: 16.3 ms − 4.2 ms
Maximum 4.2ms
Sleep
PON = 0
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PON = 1
Start
Prox
Accum
PEN = 1
ALS
AEN = 0
Prox
Check
PEN = 0
Prox
ADC
WEN = 0
ALS
Check
ALS
Delay
AEN = 1
Up to 255 steps
Step: 2.72 ms
Time: 2.72 mS − 696 ms
Recommended − 2.72 ms 1024 Counts
Wait
Check
Time: 2.72 ms
WEN = 0
WEN = 1
Wait
WLONG = 0
Counts up to 256 steps
Step: 2.72 ms
Time: 2.72 ms − 696 ms
Minimum − 2.72 ms
WLONG = 1
Counts up to 256 steps
Step: 32.64 ms
Time: 32.64 ms − 8.35 s
Minimum − 32.64 ms
Te
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ca
Figure 11. Expanded State Diagram
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TMD2771
DIGITAL ALS
and PROXIMITY MODULE
TAOS143B − SEPTEMBER 2012
Power Management
Power consumption can be controlled through the use of the wait state timing because the wait state consumes
only 65 μA of power. Figure 12 shows an example of using the power management feature to achieve an
average power consumption of 151 μA current with four 100-mA pulses of proximity detection and 50 ms of ALS
detection.
Prox ADC
65 ms (29 ms LED On Time)
2.72 ms
Example: ~100 ms Cycle TIme
WAIT
49 ms
Duration (ms)
Current (mA)
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State
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Prox Accum
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4 IR LED Pulses
ALS
Prox Accum
LED On
Prox ADC
Wait
ALS
49 ms
0.065 (Note 1)
0.029 (Note 2)
2.72
49
49
100.0
0.175
0.065
0.175
Avg = ((0.029 100) + (2.72 0.175) + (49 0.065) + (49 0.175)) / 100 = 151 mA
Note 1: Prox Accum = 16.3 ms per pulse 4 pulses = 65 ms = 0.065 ms
Note 2: LED On = 7.2 ms per pulse 4 pulses = 29 ms = 0.029 ms
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Figure 12. Power Consumption Calculations
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TMD2771
DIGITAL ALS
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I2C Protocol
Interface and control are accomplished through an I2C serial compatible interface (standard or fast mode) to
a set of registers that provide access to device control functions and output data. The device supports the 7-bit
I2C addressing protocol.
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The I2C standard provides for three types of bus transaction: read, write, and a combined protocol (Figure 13).
During a write operation, the first byte written is a command byte followed by data. In a combined protocol, the
first byte written is the command byte followed by reading a series of bytes. If a read command is issued, the
register address from the previous command will be used for data access. Likewise, if the MSB of the command
is not set, the device will write a series of bytes at the address stored in the last valid command with a register
address. The command byte contains either control information or a 5-bit register address. The control
commands can also be used to clear interrupts.
...
Acknowledge (0)
Not Acknowledged (1)
Stop Condition
Read (1)
Start Condition
Repeated Start Condition
Write (0)
Continuation of protocol
Master-to-Slave
Slave-to-Master
1
S
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A
N
P
R
S
Sr
W
lv
The I2C bus protocol was developed by Philips (now NXP). For a complete description of the I2C protocol, please
review the NXP I2C design specification at http://www.i2c−bus.org/references/.
7
1
Slave Address
W
1
8
A
1
Command Code
8
A
1
Data Byte
A
8
1
1
...
P
I2C Write Protocol
1
S
7
1
Slave Address
R
1
8
A
1
Data
A
Data
1
...
A
P
I2C Read Protocol
1
S
Slave Address
1
8
1
1
7
1
1
A
Command Code
A
Sr
Slave Address
R
A
ca
7
W
8
1
Data
A
8
Data
1
A
1
...
P
I2C Read Protocol — Combined Format
Figure 13. I2C Protocols
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1
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TMD2771
DIGITAL ALS
and PROXIMITY MODULE
TAOS143B − SEPTEMBER 2012
Register Set
The device is controlled and monitored by data registers and a command register accessed through the serial
interface. These registers provide for a variety of control functions and can be read to determine results of the
ADC conversions. The register set is summarized in Table 1.
Table 1. Register Address
ADDRESS
RESISTER NAME
R/W
−−
COMMAND
W
0x00
ENABLE
R/W
Enables states and interrupts
0x01
ATIME
R/W
ALS ADC time
0x02
PTIME
R/W
Proximity ADC time
0x03
WTIME
R/W
Wait time
0x04
AILTL
R/W
ALS interrupt low threshold low byte
0x05
AILTH
R/W
ALS interrupt low threshold high byte
0x06
AIHTL
R/W
ALS interrupt high threshold low byte
0x07
AIHTH
R/W
ALS interrupt high threshold high byte
0x08
PILTL
R/W
Proximity interrupt low threshold low byte
0x00
R/W
Proximity interrupt low threshold high byte
0x00
R/W
Proximity interrupt high threshold low byte
0x00
R/W
Proximity interrupt high threshold high byte
0x00
R/W
Interrupt persistence filters
0x00
R/W
Configuration
0x00
PILTH
PIHTL
0x0B
PIHTH
0x0C
PERS
0x0D
CONFIG
RESET VALUE
al
id
0x00
0x00
0x001
0xFF
0xFF
lv
0x00
0x00
0x00
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0x09
0x0A
REGISTER FUNCTION
Specifies register address
0x00
0x0E
PPULSE
R/W
Proximity pulse count
0x00
0x0F
CONTROL
R/W
Control register
0x00
0x12
ID
R
Device ID
0x13
STATUS
R
Device status
0x00
0x14
C0DATA
R
CH0 ADC low data register
0x00
0x15
C0DATAH
R
CH0 ADC high data register
0x00
0x16
C1DATA
R
CH1 ADC low data register
0x00
0x17
C1DATAH
R
CH1 ADC high data register
0x00
R
Proximity ADC low data register
0x00
R
Proximity ADC high data register
0x00
PDATA
0x19
PDATAH
ca
0x18
ID
NOTE 1: The reset value is the longest ATIME duration. Following power on, this register should be initialized to an appropriate value.
Te
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ni
The mechanics of accessing a specific register depends on the specific protocol used. See the section on I2C
protocols on the previous pages. In general, the COMMAND register is written first to specify the specific
control/status register for following read/write operations.
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TMD2771
DIGITAL ALS
and PROXIMITY MODULE
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Command Register
The command registers specifies the address of the target register for future write and read operations.
Table 2. Command Register
6
COMMAND
COMMAND
FIELD
BITS
COMMAND
7
TYPE
6:5
5
4
3
TYPE
2
1
0
−−
ADD
DESCRIPTION
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id
7
Select Command Register. Must write as 1 when addressing COMMAND register.
Selects type of transaction to follow in subsequent data transfers:
DESCRIPTION
00
Repeated byte protocol transaction
01
Auto-increment protocol transaction
10
Reserved — Do not use
11
Special function — See description below
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FIELD VALUE
Transaction type 00 will repeatedly read the same register with each data access.
Transaction type 01 will provide an auto-increment function to read successive register bytes.
ADD
4:0
Address register/special function register. Depending on the transaction type, see above, this field either
specifies a special function command or selects the specific control-status-register for following write and
read transactions:
FIELD VALUE
DESCRIPTION
00000
Normal — no action
00101
Proximity interrupt clear
00110
ALS interrupt clear
00111
Proximity and ALS interrupt clear
other
Reserved — Do not write
Te
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ca
The ALS and Proximity Interrupt Clear clears any pending ALS/Proximity interrupt. This special function
is self clearing.
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TMD2771
DIGITAL ALS
and PROXIMITY MODULE
TAOS143B − SEPTEMBER 2012
Enable Register (0x00)
The ENABLE register is used to power the device on/off, enable functions, and interrupts.
Table 3. Enable Register
6
Reserved
ENABLE
5
4
3
2
1
0
PIEN
Resv
AIEN
WEN
PEN
AEN
PON
DESCRIPTION
Address
0x00
al
id
7
FIELD
BITS
Reserved
7:6
PIEN
5
Proximity interrupt mask. When asserted, permits proximity interrupts to be generated.
AIEN
4
ALS interrupt mask. When asserted, permits ALS interrupts to be generated.
WEN
3
Wait Enable. This bit activates the wait feature. Writing a 1 activates the wait timer. Writing a 0 disables the
wait timer.
PEN
2
Proximity enable. This bit activates the proximity function. Writing a 1 enables proximity. Writing a 0
disables proximity.
AEN
1
ALS Enable. This bit actives the two channel ADC. Writing a 1 activates the ALS. Writing a 0 disables
the ALS.
PON 1, 2
0
Power ON. This bit activates the internal oscillator to permit the timers and ADC channels to operate.
Writing a 1 activates the oscillator. Writing a 0 disables the oscillator.
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Reserved. Write as 0.
NOTES: 1. See Power Management section for more information.
2. A minimum interval of 2.72 ms must pass after PON is asserted before either a proximity or ALS can be initiated. This required time
is enforced by the hardware in cases where the firmware does not provide it.
ALS Timing Register (0x01)
The ALS timing register controls the internal integration time of the ALS channel ADCs in 2.72 ms increments.
Note that the power-on default value is 0x00 (the longest ATIME duration). This register should be initialized
by the application code to a reasonable value following powerup.
Table 4. ALS Timing Register
BITS
7:0
DESCRIPTION
VALUE
INTEG_CYCLES
TIME
0xFF
1
2.72 ms
1024
0xF6
10
27.2 ms
10240
0xDB
37
101 ms
37888
0xC0
64
174 ms
65535
256
696 ms
65535
ni
ca
FIELD
ATIME
Te
ch
0x00
MAX COUNT
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DIGITAL ALS
and PROXIMITY MODULE
TAOS143B − SEPTEMBER 2012
Proximity Time Control Register (0x02)
The proximity timing register controls the integration time of the proximity ADC in 2.72 ms increments. It is
recommended that this register be programmed to a value of 0xFF (1 integration cycle).
Table 5. Proximity Time Control Register
BITS
7:0
DESCRIPTION
VALUE
INTEG_CYCLES
TIME
0xFF
1
2.72 ms
Wait Time Register (0x03)
MAX COUNT
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FIELD
PTIME
1023
lv
Wait time is set 2.72 ms increments unless the WLONG bit is asserted in which case the wait times are 12×
longer. WTIME is programmed as a 2’s complement number.
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Table 6. Wait Time Register
FIELD
BITS
WTIME
7:0
DESCRIPTION
REGISTER VALUE
WAIT TIME
TIME (WLONG = 0)
TIME (WLONG = 1)
0xFF
1
2.72 ms
0.032 sec
0xB6
74
200 ms
2.4 sec
0x00
256
700 ms
8.3 sec
NOTE: The Proximity Wait Time Register should be configured before PEN and/or AEN is/are asserted.
ALS Interrupt Threshold Registers (0x04 − 0x07)
The ALS interrupt threshold registers provides the values to be used as the high and low trigger points for the
comparison function for interrupt generation. If C0DATA crosses below the low threshold specified, or above
the higher threshold, an interrupt is asserted on the interrupt pin.
Table 7. ALS Interrupt Threshold Registers
REGISTER
AILTL
BITS
0x04
7:0
ALS low threshold lower byte
0x05
7:0
ALS low threshold upper byte
0x06
7:0
ALS high threshold lower byte
0x07
7:0
ALS high threshold upper byte
ca
AILTH
ADDRESS
AIHTL
Te
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AIHTH
DESCRIPTION
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TMD2771
DIGITAL ALS
and PROXIMITY MODULE
TAOS143B − SEPTEMBER 2012
Proximity Interrupt Threshold Registers (0x08 − 0x0B)
The proximity interrupt threshold registers provide the values to be used as the high and low trigger points for
the comparison function for interrupt generation. If the value generated by proximity channel crosses below the
lower threshold specified, or above the higher threshold, an interrupt is signaled to the host processor.
Table 8. Proximity Interrupt Threshold Registers
BITS
0x08
7:0
Proximity low threshold lower byte
DESCRIPTION
PILTH
0x09
7:0
Proximity low threshold upper byte
PIHTL
0x0A
7:0
Proximity high threshold lower byte
PIHTH
0x0B
7:0
Proximity high threshold upper byte
al
id
ADDRESS
PILTL
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REGISTER
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DIGITAL ALS
and PROXIMITY MODULE
TAOS143B − SEPTEMBER 2012
Persistence Register (0x0C)
The persistence register controls the filtering interrupt capabilities of the device. Configurable filtering is
provided to allow interrupts to be generated after each ADC integration cycle or if the ADC integration has
produced a result that is outside of the values specified by threshold register for some specified amount of time.
Separate filtering is provided for proximity and ALS functions. ALS interrupts are generated using C0DATA.
Table 9. Persistence Register
6
PERS
5
4
3
PPERS
FIELD
BITS
PPERS
7:4
0
Address
0x0C
DESCRIPTION
FIELD VALUE
MEANING
0000
−−−
0001
1
lv
Proximity interrupt persistence. Controls rate of proximity interrupt to the host processor.
INTERRUPT PERSISTENCE FUNCTION
Every proximity cycle generates an interrupt
1 proximity value out of range
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3:0
1
APERS
0010
2
2 consecutive proximity values out of range
...
...
...
1111
15
15 consecutive proximity values out of range
Interrupt persistence. Controls rate of interrupt to the host processor.
FIELD VALUE
MEANING
0000
Every
0001
1
1 value outside of threshold range
0010
2
2 consecutive values out of range
INTERRUPT PERSISTENCE FUNCTION
Every ALS cycle generates an interrupt
0011
3
3 consecutive values out of range
0100
5
5 consecutive values out of range
0101
10
10 consecutive values out of range
0110
15
15 consecutive values out of range
0111
20
20 consecutive values out of range
1000
25
25 consecutive values out of range
1001
30
30 consecutive values out of range
1010
35
35 consecutive values out of range
1011
40
40 consecutive values out of range
1100
45
45 consecutive values out of range
1101
50
50 consecutive values out of range
1110
55
55 consecutive values out of range
1111
60
60 consecutive values out of range
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APERS
2
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7
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TMD2771
DIGITAL ALS
and PROXIMITY MODULE
TAOS143B − SEPTEMBER 2012
Configuration Register (0x0D)
The configuration register sets the wait long time.
Table 10. Configuration Register
7
6
5
CONFIG
4
3
2
0
WLONG
Reserved
Address
0x0D
al
id
Reserved
1
FIELD
BITS
Reserved
7:2
DESCRIPTION
WLONG
1
Wait Long. When asserted, the wait cycles are increased by a factor 12× from that programmed in the
WTIME register.
Reserved
0
Reserved. Write as 0.
lv
Reserved. Write as 0.
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Proximity Pulse Count Register (0x0E)
The proximity pulse count register sets the number of proximity pulses that will be transmitted. When proximity
detection is enabled, a proximity detect cycle occurs after each ALS cycle. PPULSE defines the number of
pulses to be transmitted at a 62.5-kHz rate.
While the value can be programmed up to 255 pulses, the practical limit of the device is 32 pulses. It is
recommended that 32 or fewer pulses be used to achieve maximum signal-to-noise ratio.
NOTE: The ATIME register will be used to time the interval between proximity detection events even if the ALS
function is disabled.
Table 11. Proximity Pulse Count Register
7
PPULSE
6
5
4
3
2
1
0
Address
0x0E
PPULSE
BITS
PPULSE
7:0
DESCRIPTION
Proximity Pulse Count. Specifies the number of proximity pulses to be generated.
Te
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FIELD
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DIGITAL ALS
and PROXIMITY MODULE
TAOS143B − SEPTEMBER 2012
Control Register (0x0F)
The Control register provides eight bits of miscellaneous control to the analog block. These bits typically control
functions such as gain settings and/or diode selection.
Table 12. Control Register
6
CONTROL
5
FIELD
BITS
7:6
3
ResvPDIODE
PDRIVE
PDRIVE
4
2
Reserved
DESCRIPTION
01
50%
10
25%
11
12.5%
lv
100%
Proximity Diode Select.
FIELD VALUE
Reserved
3:2
AGAIN
1:0
Address
0x0F
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5:4
LED STRENGTH
00
0
AGAIN
LED Drive Strength.
FIELD VALUE
PDIODE
1
al
id
7
DIODE SELECTION
00
Reserved
01
Proximity uses the Channel 0 diode
10
Proximity uses the Channel 1 diode
11
Proximity uses both diodes
Reserved.
Write bits as 0 (0:0)
ALS Gain Control.
FIELD VALUE
ALS GAIN VALUE
00
1× gain
01
8× gain
10
16× gain
11
120× gain
ID Register (0x12)
ca
NOTE: The PDRIVE values are relative to the factory-trimmed current necessary to meet the Prox Count
specification shown on page 4.
ni
The ID Register provides the value for the part number. The ID register is a read-only register.
ID
6
5
ch
7
Table 13. ID Register
Te
FIELD
ID
4
3
1
DESCRIPTION
0x20 = TMD27711
Part number identification
The LUMENOLOGY r Company
0
Address
0x12
ID
BITS
7:0
2
0x29 = TMD27713
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23
TMD2771
DIGITAL ALS
and PROXIMITY MODULE
TAOS143B − SEPTEMBER 2012
Status Register (0x13)
The Status Register provides the internal status of the device. This register is read only.
Table 14. Status Register
STATUS
6
Reserved
5
4
PINT
Resv
AINT
3
2
1
0
Reserved
AVALID
FIELD
BIT
Reserved
7:6
DESCRIPTION
PINT
5
Proximity Interrupt. Indicates that the device is asserting a proximity interrupt.
AINT
4
ALS Interrupt. Indicates that the device is asserting an ALS interrupt.
Reserved
3:1
AVALID
0
Reserved.
lv
Reserved.
Address
0x13
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7
ALS Valid. Indicates that the ALS channels have completed an integration cycle.
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ADC Channel Data Registers (0x14 − 0x17)
ALS data is stored as two 16-bit values. To ensure the data is read correctly, a two-byte read I2C transaction
should be used with auto increment protocol bits set in the command register. With this operation, when the
lower byte register is read, the upper eight bits are stored in a shadow register, which is read by a subsequent
read to the upper byte. The upper register will read the correct value even if additional ADC integration cycles
end between the reading of the lower and upper registers.
Table 15. ADC Channel Data Registers
REGISTER
ADDRESS
BITS
DESCRIPTION
C0DATA
0x14
7:0
ALS Channel 0 data low byte
C0DATAH
0x15
7:0
ALS Channel 0 data high byte
C1DATA
0x16
7:0
ALS Channel 1 data low byte
C1DATAH
0x17
7:0
ALS Channel 1 data high byte
Proximity Data Register (0x18 − 0x19h)
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Proximity data is stored as a 16-bit value. To ensure the data is read correctly, a two-byte read I2C transaction
should be utilized with auto increment protocol bits set in the command register. With this operation, when the
lower byte register is read, the upper eight bits are stored into a shadow register, which is read by a subsequent
read to the upper byte. The upper register will read the correct value even if the next ADC cycle ends between
the reading of the lower and upper registers.
Table 16. PDATA Registers
ADDRESS
BITS
DESCRIPTION
PDATAL
0x18
7:0
Proximity data low byte
PDATAH
0x19
7:0
Proximity data high byte
Te
REGISTER
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TMD2771
DIGITAL ALS
and PROXIMITY MODULE
TAOS143B − SEPTEMBER 2012
APPLICATION INFORMATION: HARDWARE
LED Driver Pin with Proximity Detection
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In a proximity sensing system, the included IR LED can be pulsed with more than 100 mA of rapidly switching
current, therefore, a few design considerations must be kept in mind to get the best performance. The key goal
is to reduce the power supply noise coupled back into the device during the LED pulses. Averaging of multiple
proximity samples is recommended to reduce the proximity noise.
The first recommendation is to use two power supplies; one for the device VDD and the other for the IR LED.
In many systems, there is a quiet analog supply and a noisy digital supply. By connecting the quiet supply to
the VDD pin and the noisy supply to the LEDA pin, the key goal can be met. Place a 1-μF low-ESR decoupling
capacitor as close as possible to the VDD pin and another at the LEDA pin, and a 22-μF capacitor at the output
of the LED voltage regulator to supply the 100-mA current surge.
Voltage
Regulator
LDR
RP
RP
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1 mF
C*
GND
Voltage
Regulator
LEDK
VDD
lv
VBUS
TMD2771
RPI
INT
SCL
LEDA
22 mF
SDA
1 mF
* Cap Value Per Regulator Manufacturer Recommendation
Figure 14. Proximity Sensing Using Separate Power Supplies
If it is not possible to provide two separate power supplies, the device can be operated from a single supply.
A 22-Ω resistor in series with the VDD supply line and a 1-μF low ESR capacitor effectively filter any power supply
noise. The previous capacitor placement considerations apply.
VBUS
Voltage
Regulator
22 W
LEDK
VDD
LDR
1 mF
GND
TMD2771
RP
RP
RPI
INT
SCL
LEDA
SDA
ni
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22 mF
ch
1 mF
Figure 15. Proximity Sensing Using Single Power Supply
Te
VBUS in the above figures refers to the I2C bus voltage which is either VDD or 1.8 V. Be sure to apply the specified
I2C bus voltage shown in the Available Options table for the specific device being used.
The I2C signals and the Interrupt are open-drain outputs and require pull−up resistors. The pull-up resistor (RP)
value is a function of the I2C bus speed, the I2C bus voltage, and the capacitive load. The TAOS EVM running
at 400 kbps, uses 1.5-kΩ resistors. A 10-kΩ pull-up resistor (RPI) can be used for the interrupt line.
The LUMENOLOGY r Company
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25
TMD2771
DIGITAL ALS
and PROXIMITY MODULE
TAOS143B − SEPTEMBER 2012
APPLICATION INFORMATION: HARDWARE
PCB Pad Layout
0.60 0.05
0.80 0.05
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lv
0.72 0.05
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Suggested PCB pad layout guidelines for the surface mount module are shown in Figure 16. Flash Gold is
recommended surface finish for the landing pads.
0.25 0.05
NOTES: A. All linear dimensions are in mm.
B. This drawing is subject to change without notice.
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Figure 16. Suggested Module PCB Layout
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26
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TMD2771
DIGITAL ALS
and PROXIMITY MODULE
TAOS143B − SEPTEMBER 2012
PACKAGE INFORMATION
MODULE
Dual Flat No-Lead
TOP VIEW
SIDE VIEW
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Detector
1.0
3.94
0.2
2.40
3.73
0.1
lv
0.9
LED
0.58
END VIEW
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1.18
2.36 0.2
1.35
0.2
2.10 0.1
BOTTOM VIEW
0.80
ca
0.60
0.25
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ni
0.72
0.05
Lead Free
All linear dimensions are in millimeters. Dimension tolerance is ± 0.05 mm unless otherwise noted.
Contacts are copper with NiPdAu plating.
This package contains no lead (Pb).
This drawing is subject to change without notice.
Te
NOTES: A.
B.
C.
D.
Pb
The LUMENOLOGY r Company
Figure 17. Module Packaging Configuration
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27
TMD2771
DIGITAL ALS
and PROXIMITY MODULE
TAOS143B − SEPTEMBER 2012
CARRIER TAPE AND REEL INFORMATION
TOP VIEW
8.00
1.75
4.00
1.50
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2.00 0.05
B
5.50 0.05
B
1.00
0.05
Unit Orientation
A
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DETAIL A
A
lv
+ 0.30
12.00
− 0.10
DETAIL B
6 Max
8 Max
0.29
0.02
2.70
Ao
Bo
Ko
ca
All linear dimensions are in millimeters. Dimension tolerance is ± 0.10 mm unless otherwise noted.
The dimensions on this drawing are for illustrative purposes only. Dimensions of an actual carrier may vary slightly.
Symbols on drawing Ao, Bo, and Ko are defined in ANSI EIA Standard 481−B 2001.
Each reel is 330 millimeters in diameter and contains 2500 parts.
TAOS packaging tape and reel conform to the requirements of EIA Standard 481−B.
In accordance with EIA standard, device pin 1 is located next to the sprocket holes in the tape.
This drawing is subject to change without notice.
ni
NOTES: A.
B.
C.
D.
E.
F.
G.
4.30
1.70
Te
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Figure 18. Module Carrier Tape
Copyright E 2012, TAOS Inc.
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TMD2771
DIGITAL ALS
and PROXIMITY MODULE
TAOS143B − SEPTEMBER 2012
SOLDERING INFORMATION
The module has been tested and has demonstrated an ability to be reflow soldered to a PCB substrate. The
process, equipment, and materials used in these test are detailed below.
Table 17. Solder Reflow Profile
PARAMETER
REFERENCE
DEVICE
Average temperature gradient in preheating
2 to 3 minutes
Time above 217°C (T1)
t1
Max 60 sec
Time above 230°C (T2)
Time above Tpeak −10°C (T3)
Peak temperature in reflow
t2
Max 50 sec
t3
Max 10 sec
lv
tsoak
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Soak time
2.5°C/sec
Tpeak
260°C
Temperature gradient in cooling
Max −5°C/sec
Not to scale — for reference only
T3
T2
Temperature (C)
T1
ca
Tpeak
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The solder reflow profile describes the expected maximum heat exposure of components during the solder
reflow process of product on a PCB. Temperature is measured on top of component. The components should
be limited to a maximum of three passes through this solder reflow profile.
t3
t2
tsoak
t1
Figure 19. Solder Reflow Profile Graph
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Time (sec)
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29
TMD2771
DIGITAL ALS
and PROXIMITY MODULE
TAOS143B − SEPTEMBER 2012
STORAGE INFORMATION
Moisture Sensitivity
al
id
Optical characteristics of the device can be adversely affected during the soldering process by the release and
vaporization of moisture that has been previously absorbed into the package. To ensure the package contains
the smallest amount of absorbed moisture possible, each device is dry-baked prior to being packed for shipping.
Devices are packed in a sealed aluminized envelope called a moisture barrier bag with silica gel to protect them
from ambient moisture during shipping, handling, and storage before use.
The Moisture Barrier Bags should be stored under the following conditions:
< 40°C
< 90%
No longer than 12 months from the date code on the aluminized envelope if
unopened.
lv
Temperature Range
Relative Humidity
Total Time
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Rebaking of the reel will be required if the devices have been stored unopened for more than 12 months and
the Humidity Indicator Card shows the parts to be out of the allowable moisture region.
Opened reels should be used within 168 hours if exposed to the following conditions:
Temperature Range
Relative Humidity
< 30°C
< 60%
If rebaking is required, it should be done at 50°C for 12 hours.
Te
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The Module has been assigned a moisture sensitivity level of MSL 3.
Copyright E 2012, TAOS Inc.
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r
r
30
www.taosinc.com
TMD2771
DIGITAL ALS
and PROXIMITY MODULE
TAOS143B − SEPTEMBER 2012
PRODUCTION DATA — information in this document is current at publication date. Products conform to
specifications in accordance with the terms of Texas Advanced Optoelectronic Solutions, Inc. standard
warranty. Production processing does not necessarily include testing of all parameters.
LEAD-FREE (Pb-FREE) and GREEN STATEMENT
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Pb-Free (RoHS) TAOS’ terms Lead-Free or Pb-Free mean semiconductor products that are compatible with the current
RoHS requirements for all 6 substances, including the requirement that lead not exceed 0.1% by weight in homogeneous
materials. Where designed to be soldered at high temperatures, TAOS Pb-Free products are suitable for use in specified
lead-free processes.
Green (RoHS & no Sb/Br) TAOS defines Green to mean Pb-Free (RoHS compatible), and free of Bromine (Br) and
Antimony (Sb) based flame retardants (Br or Sb do not exceed 0.1% by weight in homogeneous material).
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Important Information and Disclaimer The information provided in this statement represents TAOS’ knowledge and
belief as of the date that it is provided. TAOS bases its knowledge and belief on information provided by third parties,
and makes no representation or warranty as to the accuracy of such information. Efforts are underway to better integrate
information from third parties. TAOS has taken and continues to take reasonable steps to provide representative
and accurate information but may not have conducted destructive testing or chemical analysis on incoming materials and
chemicals. TAOS and TAOS suppliers consider certain information to be proprietary, and thus CAS numbers and other
limited information may not be available for release.
NOTICE
Texas Advanced Optoelectronic Solutions, Inc. (TAOS) reserves the right to make changes to the products contained in this
document to improve performance or for any other purpose, or to discontinue them without notice. Customers are advised
to contact TAOS to obtain the latest product information before placing orders or designing TAOS products into systems.
TAOS assumes no responsibility for the use of any products or circuits described in this document or customer product
design, conveys no license, either expressed or implied, under any patent or other right, and makes no representation that
the circuits are free of patent infringement. TAOS further makes no claim as to the suitability of its products for any particular
purpose, nor does TAOS assume any liability arising out of the use of any product or circuit, and specifically disclaims any
and all liability, including without limitation consequential or incidental damages.
ca
TEXAS ADVANCED OPTOELECTRONIC SOLUTIONS, INC. PRODUCTS ARE NOT DESIGNED OR INTENDED FOR
USE IN CRITICAL APPLICATIONS IN WHICH THE FAILURE OR MALFUNCTION OF THE TAOS PRODUCT MAY
RESULT IN PERSONAL INJURY OR DEATH. USE OF TAOS PRODUCTS IN LIFE SUPPORT SYSTEMS IS EXPRESSLY
UNAUTHORIZED AND ANY SUCH USE BY A CUSTOMER IS COMPLETELY AT THE CUSTOMER’S RISK.
Te
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LUMENOLOGY, TAOS, the TAOS logo, and Texas Advanced Optoelectronic Solutions are registered trademarks of Texas Advanced
Optoelectronic Solutions Incorporated.
The LUMENOLOGY r Company
Copyright E 2012, TAOS Inc.
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31
TMD2771
DIGITAL ALS
and PROXIMITY MODULE
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TAOS143B − SEPTEMBER 2012
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The LUMENOLOGY r Company
r
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32
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