Ambient Light Sensor with I 2 C Interface

NOA1302
Ambient Light Sensor with
I2C Interface
Description
The NOA1302 integrates a wide dynamic range ambient light
sensor (ALS) with a 16−bit ADC and a 2−wire I2C digital interface.
The NOA1302 ambient light sensor provides a linear response over
the range of close to 0 lux to well over 100,000 lux with programmable
integration times to optimize noise performance. The sensor employs
proprietary CMOS image sensing technology from ON Semiconductor
which provides low noise and high dynamic range output signals and
light response similar to the response of the human eye.
The NOA1302 operates as an I2C slave device and supports
commands to set options in the device and read out the ambient light
intensity count.
http://onsemi.com
CTSSOP−8
DC SUFFIX
CASE 949AA
MARKING DIAGRAM
Features
• Senses Ambient Light and Provides an Output Count Proportional to
8
the Ambient Light Intensity
•
•
•
•
•
•
•
•
ÉÉ
ÉÉ
1302
• Human Eye Type of Spectral Response
• Provides Comfortable Levels of Display Depending on the Viewing
AYWG
1
Environment
Linear Response Over the Full Operating Range
Senses Intensity of Ambient Light from ~0 Lux to over 100,000 Lux
Programmable Integration Times of 400 ms, 200 ms and 100 ms
No External Components Required
Low Power Consumption
Built−in 16−bit ADC
I2C Serial Communication Port − Standard Mode – 100 kHz
− Fast Mode – 400 kHz
This Device is Pb−Free, Halogen Free/BFR Free, and RoHS
Compliant
1302= Specific Device Code
A
= Assembly Location
Y
= Year
W = Work Week
G
= Pb−Free Package
PIN ASSIGNMENT
NC
NC
VSS
SCL
1
ÉÉ
ÉÉ
8
NC
NC
VDD
SDA
(Top View)
Applications
• Saves Display Power in Applications such as:
ORDERING INFORMATION
− Laptops, Notebooks, Digital Signage
− LCD TVs and Monitors, Digital Picture Frames
− LED Indoor/Outdoor Residential and Street Lights
See detailed ordering and shipping information in the package
dimensions section on page 2 of this data sheet.
Vin = 3.3 V
hv
C1
10m
R1
1k
C2
0.1m
R2
1k
6 VDD
SDA 5
SDA
3 VSS
SCL 4
SCL
IC1
NOA1302
MCU
CL not to exceed 250 pF
including all parasitic
capacitances
Figure 1. Typical Application Circuit
© Semiconductor Components Industries, LLC, 2009
August, 2009 − Rev. 1
1
Publication Order Number:
NOA1302/D
NOA1302
Table 1. ORDERING INFORMATION
Package
Shipping Configuration†
Temperature Range
CTSSOP−8
(Pb−Free)
2500 / Tape & Reel
0°C to 70°C
Part Number
NOA1302DCRG
†For information on tape and reel specifications, including part orientation and tape sizes, please refer to our Tape and Reel Packaging
Specification Brochure, BRD8011/D.
ADC
hn
16−bits
Control
I2C Serial
Interface
SCL
SDA
Figure 2. Simplified Block Diagram
Table 2. PIN FUNCTION DESCRIPTION
Pin
Pin Name
Description
1, 2, 7, 8
N/C
Not connected, leave this pin unconnected.
3
VSS
Ground pin.
4
SCL
External I2C clock supplied by the I2C master.
5
SDA
Bi−directional data signal for communications between this device and the I2C master.
6
VDD
Power pin.
Table 3. ABSOLUTE MAXIMUM RATINGS
Rating
Symbol
Value
Unit
Input power supply
VDD
5.5
V
Input voltage range
Vin
−0.3 to VDD + 0.2
V
Output voltage range
Vout
−0.3 to VDD + 0.2
V
TJ(max)
85
°C
TSTG
−40 to 85
°C
ESDHBM
ESDCDM
ESDMM
2.5
750
250
kV
V
V
Moisture Sensitivity Level
MSL
3
−
Lead Temperature Soldering (Note 2)
TSLD
260
°C
Maximum Junction Temperature
Storage Temperature
ESD Capability, Human Body Model (Note 1)
ESD Capability, Charged Device Model (Note 1)
ESD Capability, Machine Model (Note 1)
Stresses exceeding Maximum Ratings may damage the device. Maximum Ratings are stress ratings only. Functional operation above the
Recommended Operating Conditions is not implied. Extended exposure to stresses above the Recommended Operating Conditions may affect
device reliability.
1. This device incorporates ESD protection and is tested by the following methods:
ESD Human Body Model tested per EIA/JESD22−A114
ESD Charged Device Model tested per ESD−STM5.3.1−1999
ESD Machine Model tested per EIA/JESD22−A115
Latchup Current Maximum Rating: ≤ 100 mA per JEDEC standard: JESD78
2. For information, please refer to our Soldering and Mounting Techniques Reference Manual, SOLDERRM/D
http://onsemi.com
2
NOA1302
Table 4. OPERATING RANGES
Standard Mode
Fast Mode
Symbol
Min
Max
Min
Max
Unit
Power supply voltage
VDD
3.0
3.6
3.0
3.6
V
Power supply current (VDD = 3.3 V)
IDD
325
950
325
950
mA
Rating
Low level input voltage (VDD related input levels)
VIL
−0.3
0.3 VDD
−0.3
0.3 VDD
V
High level input voltage (VDD related input levels)
VIH
0.7 VDD
VDD + 0.2
0.7 VDD
VDD + 0.2
V
Hysteresis of Schmitt trigger inputs (VDD > 2 V)
Vhys
N/A
N/A
0.05 VDD
−
V
Low level output voltage (open drain) at 3 mA sink
current (VDD > 2 V)
VOL
0
0.4
0
0.4
V
High level output voltage (with 1 kW pullup resistance) at and output current of −20 mA (VDD > 2 V)
VOH
VDD − 0.1
N/A
VDD − 0.1
N/A
V
II
−10
10
−10
10
mA
Output low current
IOL
−
45
−
45
mA
Capacitance on IO pin
CI
−
10
−
10
pF
Operating free−air temperature range
TA
0
70
0
70
°C
Input current of IO pin with an input voltage
between 0.1 VDD and 0.9 VDD
Table 5. ELECTRICAL CHARACTERISTICS
(Unless otherwise specified, these specifications apply over VDD = 3.3 V, 0°C < TA < 70°C) (Note 3)
Standard Mode
Parameter
Symbol
Min
Max
Min
Max
Unit
fSCL
10
100
100
400
kHz
tHD;STA
4.0
−
0.6
−
mS
tLOW
4.7
SCL clock frequency
Hold time for START condition. After this period, the first clock
pulse is generated.
Fast Mode
Low period of SCL clock
High period of SCL clock
1.3
mS
tHIGH
4.0
tHD;DAT_d
0
3.45
0
0.9
mS
Data set−up time
tSU;DAT
250
−
100
−
nS
Rise time of both SDA and SCL (input signals) (Note 4)
tr_INPUT
5
300
5
300
nS
Fall time of both SDA and SCL (input signals) (Note 4)
tf_INPUT
5
300
5
300
nS
Rise time of SDA output signal (Note 4)
tr_OUT
−
1000
−
1000
nS
Fall time of SDA output signal (Note 4)
tf_OUT
−
1000
−
1000
nS
tof
2
250
2
250
nS
tSU;STO
4.0
−
0.6
−
mS
Data hold time for I2C−bus devices
Output fall time from VIHmin to VILmax with a bus capacitance
from 10 pF to 250 pF. (Note 5)
Set−up time for STOP condition
Bus free time between STOP and START condition
0.6
mS
tBUF
4.7
−
1.3
−
mS
Capacitive load for each bus line
(including all parasitic capacitance)
CL
−
250
−
250
pF
Noise margin at the low level for each connected device
(including hysteresis)
VnL
0.1 VDD
−
0.1 VDD
−
V
Noise margin at the high level for each connected device
(including hysteresis)
VnH
0.2 VDD
−
0.2 VDD
−
V
3. Refer to Figure 3 for more information on AC characteristics
4. The rise time and fall time are measured with a pull−up resistor Rp = 1 kW and Cb of 250 pF (including all parasitic capacitances).
5. Cb = capacitance of one bus line, maximum value of which including all parasitic capacitances should be less than 250 pF.
http://onsemi.com
3
NOA1302
Table 6. OPTICAL CHARACTERISTICS (Unless otherwise specified, these specifications are for VDD = 3.3 V, TA = 25°C)
Test Conditions
Parameter
Symbol
Min
Typ
Max
Unit
Irradiance responsivity
lp (see Figure 5)
Re
545
nM
Illuminance responsivity
Incandescent light source:
Ev = 100 lux (see Figure 6)
Rv
150
Counts
Incandescent light source:
Ev = 1000 lux (see Figure 6)
Illuminance responsivity
1480
Fluorescent light source:
Ev = 100 lux (see Figure 7)
Rv
Fluorescent light source:
Ev = 1000 lux (see Figure 7)
Dark current
Counts
130
1290
Ev = 0 lux (see Figure 9)
2
Counts
SDA
tLOW
tf
tr
tSU;DAT
tf
tSP
tBUF
tr
SCL
S
tHD;STA
tHD;DAT
tSU;STO
tHIGH
Figure 3. AC Characteristics
http://onsemi.com
4
P
S
NOA1302
TYPICAL CHARACTERISTICS
Figure 4. Photo Diode Spectral Response (Without Filter)
Figure 5. Human Eye vs. NOA1302 Spectral
Response
Figure 6. Incandescent Light Response
(200 ms Integration)
Figure 7. Fluorescent Light Response
(200 ms Integration)
Figure 8. Light Response vs. VDD
Figure 9. Dark Counts vs. Temperature
(200 ms Integration)
http://onsemi.com
5
NOA1302
TYPICAL CHARACTERISTICS
Figure 10. Dark Counts vs. Vdd
Figure 11. Idd vs. Temperature
Figure 12. Idd vs.Vdd
Figure 13. Idd vs Ev
Figure 14. Maximum Value of RP (in kW)
as a function of Bus Capacitance (in pF)
http://onsemi.com
6
NOA1302
DESCRIPTION OF OPERATION
Ambient Light Sensor Architecture
sent MSB first. RD/WR_ command bit follows the address
bits. Upon receiving a valid address the device responds by
driving SDA low for an ACK. After receiving an ACK, the
I2C master sends eight bits of data with MSB first. Upon
receiving eight bits of data the NOA1302 generates an ACK.
The I2C master terminates this write command with a stop
condition.
The NOA1302 employs a sensitive photo diode fabricated
in ON Semiconductor’s standard CMOS process
technology. The major components of this sensor are as
shown in Figure 2. The photons which are to be detected pass
through an ON Semiconductor proprietary color filter
limiting extraneous photons and thus performing as a band
pass filter on the incident wave front. The filter only
transmits photons in the visible spectrum which are
primarily detected by the human eye. The photo response of
this sensor is as shown in Figure 5.
The ambient light signal detected by the photo diode is
converted to digital signal using a variable slope integrating
ADC with a resolution of 16−bits, unsigned. The ADC value
is provided to the control block connected to the I2C
interface block.
Equation 1 shows the relationship of output counts Cnt as
a function of integration constant Ik, integration time Tint (in
seconds) and the intensity of the ambient light, IL(in lux), at
room temperature (25°C).
IL +
C nt
(I k @ T int)
SDA
C nt
(6.67 @ T int)
C nt
(7.5 @ T int)
D[7:0]
ACK
Stop
Condition
Figure 15. I2C Write Command
Figure 16 shows an I2C read command sent by the master
to the slave device. The I2C read command begins with a
start condition. After the start condition, seven bits of
address are sent by the master MSB first, followed by the
RD/WR_ command bit. For a read command the RD/WR_
bit is high. Upon receiving the address bits and RD/WR_
command bits the device responds with an ACK. After
sending an ACK, the device sends eight bits of data MSB
first. After receiving the data, the master terminates this
transaction by issuing a NACK command to indicate that the
master only wanted to read one byte from the device. The
master generates a stop condition to end this transaction.
Repeated START condition is not supported. Each I2C
transaction must be terminated with a STOP condition after
all required bits have been transmitted and received.
(eq. 1)
(eq. 2)
(eq. 3)
For example let:
Cnt = 1200
Tint = 200 mS
Intensity of ambient incandescent light, IL(in lux):
1200
IL +
(7.5 @ 200 mS)
ACK
Start
Condition
and the intensity of the ambient incandescent light (in lux):
IL +
WR
SCL
Where:
Ik = 6.67 (for fluorescent light)
Ik = 7.5 (for incandescent light)
Hence the intensity of the ambient fluorescent light (in lux):
IL +
A[6:0]
SDA
A[6:0]
RD
ACK
D[7:0] NACK
SCL
(eq. 4)
Start
Condition
IL = 800 lux
Stop
Condition
Figure 16. I2C Read Command
I2C Interface
Programmer’s Model
The NOA1302 operates on the I2C bus as a slave device.
The I2C address is fixed at 0x39 (hexadecimal 39). Registers
can be programmed by sending commands over an I2C bus.
Ambient light intensity count value can be obtained by
reading registers. The ambient light intensity count is 16
bits, hence two I2C read operations are needed. This device
supports both standard (100 Kbit/s) and fast mode
(400 Kbit/s) of operation on the I2C bus.
Figure 15 shows an I2C write operation. To write to an
internal register of the NOA1302 a write command must be
sent by an I2C master. The write command begins with a start
condition. After the start condition, seven bits of address are
Ambient light intensity count is obtained from the the
NOA1302 by issuing a fixed sequence of I2C commands.
Integration time is programmable by writing different
values to the integration time register. The following
sections describe what a programmer needs to know about
issuing commands to the chip and register access.
Integration Time Register
Table 7 describes integration time register which controls
the exposure time. This register has three bits, EC[2:0]
which control the duration of the integration time.
http://onsemi.com
7
NOA1302
1. Send write command 0x1Dh to set EC[0] = 0.
2. Send write command 0x88h to set EC[1] = 1, now
EC[2:0] = 010.
Table 7. INTEGRATION TIME REGISTER
EC[2,1,0]
Operation
Integration Time
000
Normal mode of operation
400 ms
001
Normal mode of operation
200 ms (Default)
010
Normal mode of operation
100 ms
011
Test mode
16.7 ms
100
Simulation test mode use
only
1.0 ms
101
Reserved for future use
110
Reserved for future use
111
Reserved for future use
Rise and Fall Time of SDA (Output)
Proper operation of the I2C bus depends on keeping the
bus capacitance low and selecting suitable pull−up resistor
values. Figure 17 and Figure 18 show the rise and fall time
on SDA in output mode under maximum load conditions.
The measurement set−up is shown in Figure 19. Figure 14
shows the maximum value of the pull−up resistor (RP) as a
function of the I2C data bus capacitance.
Programming Sequence and Command Summary
This section describes supported commands and
programming sequence. The NOA1302 only supports single
byte write and a single byte read I2C commands. Ambient
light intensity count is 16 bits wide, thus two I2C read
commands are needed.
Table 8 describes supported commands. All of these
commands have to be sent to the fixed address (0x39).
Table 8. DEVICE COMMANDS
Command
RP = 1 kW
CL = 250 pF (including all parasitic caps)
tr = 530 ns
Function
0x00h
Start reading ADC data
0x03h
Complete reading ADC data
0x1Dh
Change EC[0] to 0
0x18h
Reset EC[2:0] to default value (001)
0x43h
Prepare ADC LS byte for reading
0x83h
Prepare ADC MS byte for reading
0x88h
Change EC[1] to 1
0x90h
Change EC[2] to 1
Figure 17. SDA Rise Time (tr)
Programming Sequence
To read 16 bits wide ambient light intensity count, the
following commands must be issued in sequence:
1. Send write command 0x00h to start the ADC
conversion cycle.
2. Send write command 0x03h to complete the ADC
cycle.
3. Send write command 0x43h to prepare the LS byte
for reading.
4. Send read byte command, returns LS byte of
count.
5. Send write command 0x83h to prepare the MS
byte for reading.
6. Send read byte command, returns MS byte of
count.
To change the integration time, for example to 100 ms, the
following commands must be used in sequence:
RP = 1 kW
CL = 250 pF (including all parasitic caps)
tf = 21 ns
Figure 18. SDA Fall Time (tf)
LED
hn
Pulse
Generator
ADC
16−bits
Control
NOA1302
I2C Serial
Interface
Figure 19. Measurement Set−up
http://onsemi.com
8
SCL
SDA
NOA1302
PACKAGE DIMENSIONS
CTSSOP8 3x3
CASE 949AA−01
ISSUE O
4X
0.20 C
D
A
8
NOTE 5
NOTES:
1. DIMENSIONING AND TOLERANCING PER ASME Y14.5M, 1994.
2. CONTROLLING DIMENSION: MILLIMETER.
3. DIMENSION b DOES NOT INCLUDE DAMBAR PROTRUSION AND IS
DETERMINED BETWEEN 0.08 AND 0.15 MM FROM THE LEAD TIP.
4. DIMENSIONS D AND E1 DOES NOT INCLUDE MOLD
PROTRUSIONS, TIE BAR BURRS, GATE BURRS OR FLASH. END
FLASH SHALL NOT EXCEED 0.25 PER SIDE. DIMENSIONS D AND
E1 DO INCLUDE ANY MOLD CAVITY MISMATCH AND ARE
DETERMINED AT THE GAUGE PLANE.
5. DATUMS A AND B TO BE DETERMINED AT THE GAUGE PLANE.
6. DETAILS OF THE PIN 1 IDENTIFIER ARE OPTIONAL, BUT MUST BE
LOCATED WITHIN THIS ZONE.
8X b
D
D2
5
0.15
M
C A-B D
NOTE 3
E2
E
E1
0.25
PIN 1
INDICATOR
NOTE 6
1
4
B
e
NOTE 5
e/2
AUXILIARY
TOP VIEW
TOP VIEW
L
M
DETAIL A
DETAIL A
A
A1
A2
C
GAUGE
PLANE
C
8X
c
0.15 C
SEATING
PLANE
SIDE VIEW
DIM
A
A1
A2
b
c
D
D2
E
E1
E2
e
L
M
MILLIMETERS
MIN
MAX
−−−
1.10
0.00
0.14
0.73
0.93
0.24
0.39
0.13
0.24
3.00 BSC
0.66
1.37
4.90 BSC
3.00 BSC
0.41
1.37
0.65 BSC
0.39
0.67
0°
8°
END VIEW
SOLDERING FOOTPRINT*
8X
0.48
8X
0.72
1.05
0.65
PITCH
DIMENSIONS: MILLIMETERS
*For additional information on our Pb−Free strategy and soldering
details, please download the ON Semiconductor Soldering and
Mounting Techniques Reference Manual, SOLDERRM/D.
ON Semiconductor and
are registered trademarks of Semiconductor Components Industries, LLC (SCILLC). SCILLC reserves the right to make changes without further notice
to any products herein. SCILLC makes no warranty, representation or guarantee regarding the suitability of its products for any particular purpose, nor does SCILLC assume any liability
arising out of the application or use of any product or circuit, and specifically disclaims any and all liability, including without limitation special, consequential or incidental damages.
“Typical” parameters which may be provided in SCILLC data sheets and/or specifications can and do vary in different applications and actual performance may vary over time. All
operating parameters, including “Typicals” must be validated for each customer application by customer’s technical experts. SCILLC does not convey any license under its patent rights
nor the rights of others. SCILLC products are not designed, intended, or authorized for use as components in systems intended for surgical implant into the body, or other applications
intended to support or sustain life, or for any other application in which the failure of the SCILLC product could create a situation where personal injury or death may occur. Should
Buyer purchase or use SCILLC products for any such unintended or unauthorized application, Buyer shall indemnify and hold SCILLC and its officers, employees, subsidiaries, affiliates,
and distributors harmless against all claims, costs, damages, and expenses, and reasonable attorney fees arising out of, directly or indirectly, any claim of personal injury or death
associated with such unintended or unauthorized use, even if such claim alleges that SCILLC was negligent regarding the design or manufacture of the part. SCILLC is an Equal
Opportunity/Affirmative Action Employer. This literature is subject to all applicable copyright laws and is not for resale in any manner.
PUBLICATION ORDERING INFORMATION
LITERATURE FULFILLMENT:
Literature Distribution Center for ON Semiconductor
P.O. Box 5163, Denver, Colorado 80217 USA
Phone: 303−675−2175 or 800−344−3860 Toll Free USA/Canada
Fax: 303−675−2176 or 800−344−3867 Toll Free USA/Canada
Email: [email protected]
N. American Technical Support: 800−282−9855 Toll Free
USA/Canada
Europe, Middle East and Africa Technical Support:
Phone: 421 33 790 2910
Japan Customer Focus Center
Phone: 81−3−5773−3850
http://onsemi.com
9
ON Semiconductor Website: www.onsemi.com
Order Literature: http://www.onsemi.com/orderlit
For additional information, please contact your local
Sales Representative
NOA1302/D
Similar pages