© Semiconductor Components Industries, LLC, 2012
October, 2012 − Rev. 0
1Publication Order Number:
NOA1305/D
NOA1305
Ambient Light Sensor with
I2C Interface and Dark
Current Compensation
Description
The NOA1305 ambient light sensor (ALS) is designed for handheld
applications and integrates a 16−bit ADC, a 2−wire I2C digital
interface, internal clock oscillator and a power down mode. The built
in dynamic dark current compensation and precision calibration
capability coupled with excellent IR and 50/60 Hz flicker rejection
enables highly accurate measurements from very low light levels to
full sunlight. The device can support simple count equals lux readings
in interrupt−driven or polling modes. The NOA1305 employs proprietary
CMOS image sensing technology from ON Semiconductor to provide
large signal to noise ratio (SNR) and wide dynamic range (DR) over
the entire operating temperature range. The optical filter used with this
chip provides a light response similar to that of the human eye.
Features
•Senses Ambient Light and Provides an Output Count Proportional to
the Ambient Light Intensity
•Photopic Spectral Response
•Dynamic Dark Current Compensation
•IR Rejection Eliminates Need for Additional IR Photodiode
•Less than 120 mA Active Power Consumption in Normal Operation
•Less than 2 mA Power Dissipation in Power Down Mode
•Interrupt Signal Notifies Host of Significant Intensity Changes
•Wide Operating Voltage Range (2.4 V to 3.6 V)
•Wide Operating Temperature Range (−40°C to 85°C)
•Linear Response Over the Full Operating Range
•Senses Intensity of Ambient Light from 0.165 Lux to Over 100K Lux
•8 Selectable Integration Times Ranging from 6.25 ms to 800 ms
•No External Components Required
•Built−in 16−bit ADC
•I2C Serial Communication Port Supports Standard and Fast Modes
•Metal Mask Programmable I2C Slave Address Option Available
•These Devices are Pb−Free and are RoHS Compliant
Applications
•Saves Display Power In Applications Such As:
♦Cell Phones, PDAs, MP3 Players, GPS
♦Cameras, Video Recorders
♦Mobile Devices with Displays or Backlit Keypads
CUDFN6
CU SUFFIX
CASE 505AD
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2
3
6
5
4
VDD
INT
SDA
VSS
NC
SCL
(Top View)
PIN ASSIGNMENT
Device Package Shipping†
ORDERING INFORMATION
NOA1305CUTAG CUDFN6
(Pb−Free)
2500 / Tape &
Reel
†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.
Temperature Range
−40°C to 85°C
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Figure 1. Typical Application Circuit
SDA
SCL
VDD
VSS
R1
1k R2
1k
Vin = 2.0 to 3.6 V
IC1
NOA1305
MCU
SDA
SCL
all parasitic capacitances
INT
R3
1k
INT 5
3
4
6
1
C1
10 m
hn
C2
10 m
Cb not to exceed 400 pF including
Figure 2. Simplified Block Diagram
Photo
Diode
Reference
Diode
ADC
SDA
SCL
INT
Osc
I2
C Interface
&
Control
ADC &
Control
I2C Interface
hn
Table 1. PIN FUNCTION DESCRIPTION
Pin Pin Name Description
1 VSS Ground pin.
2 NC No connection.
3 SCL External I2C clock supplied by the I2C master. Requires a 1 kW pull−up resistor.
4 SDA Bi−directional data signal for communications between this device and the I2C master. Requires a 1 kW
pull−up resistor.
5 INT Interrupt request to the host. Programmable active state, open−drain output and requires an external
1kW pull−up resistor.
6 VDD Power pin.
Table 2. ABSOLUTE MAXIMUM RATINGS
Rating Symbol Value Unit
Input power supply VDD 4.0 V
Input voltage range Vin −0.3 to VDD + 0.2 V
Output voltage range Vout −0.3 to VDD + 0.2 V
Maximum Junction Temperature TJ(max) 85 °C
Storage Temperature TSTG −40 to 85 °C
ESD Capability, Human Body Model (Note 1) ESDHBM 2 kV
ESD Capability, Charged Device Model (Note 1) ESDCDM 750 (corner pins), 500 (center pins) V
ESD Capability, Machine Model (Note 1) ESDMM 200 V
Moisture Sensitivity Level MSL 5 −
Lead Temperature Soldering (Note 2) TSLD 260 °C
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
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Table 3. OPERATING RANGES
Rating Symbol
Standard Mode Fast Mode
Unit
Min Max Min Max
Power supply voltage VDD 2.4 3.6 2.4 3.6 V
Power supply current IDD 120 120 mA
Quiescent supply current (Note 3) IDD_qe 2.0 2.0 mA
Low level input voltage (VDD related input levels) VIL −0.5 0.3 VDD −0.5 0.3 VDD V
High level input voltage (VDD related input levels) (Note 4) VIH 0.7 VDD VDD + 0.5 0.7 VDD VDD + 0.5 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
Output low current (VOl=0.4 V) IOL 3 N/A 3 N/A mA
Output low current (VOl=0.6 V) IOL N/A N/A 6 N/A mA
Output fall time from VIHmin to VILmax with a bus capacit-
ance, Cb from 10 pF to 400 pF (Note 4)
tof −250 20+0.1Cb250 ns
Pulse width of spikes which must be suppressed by the
input filter
tSP N/A N/A 0 50 ns
Input current of IO pin with an input voltage between 0.1
VDD and 0.9 VDD
II−10 10 −10 10 mA
Capacitance on IO pin CI−10 −10 pF
Operating free−air temperature range TA−40 85 −40 85 °C
3. Current dissipation when a software Power Down command is sent to the device.
4. Cb = capacitance of one bus line, maximum value of which including all parasitic capacitances should be less than 400 pF.
Table 4. ELECTRICAL CHARACTERISTICS
(Unless otherwise specified, these specifications apply over VDD = 3.3 V, −40°C < TA < 85°C) (Note 5)
Parameter Symbol
Standard Mode Fast Mode
Unit
Min Max Min Max
SCL clock frequency fSCL 0 100 0 400 kHz
Hold time for START condition. After this period, the first
clock pulse is generated.
tHD;STA 4.0 −0.6 −mS
Low period of SCL clock tLOW 4.7 1.3 mS
High period of SCL clock tHIGH 4.0 0.6 mS
Set−up time for a repeated START condition tSU;STA 4.7 −0.6 −mS
Data hold time for I2C−bus devices 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 (Note 6) tr−1000 20 + 0.1Cb300 nS
Fall time of both SDA and SCL (Note 6) tf−300 20 + 0.1Cb300 nS
Set−up time for STOP condition tSU;STO 4.0 −0.6 −mS
Bus free time between STOP and START condition tBUF 4.7 −1.3 −mS
Capacitive load for each bus line Cb−400 −400 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
Parameter Symbol Typ Typ Unit
Internal Oscillator Frequency fosc 1 1 MHz
5. Refer to Figure 3 for more information on AC characteristics
6. The rise time and fall time are measured with a pull−up resistor Rp = 1 kW and Cb of 400 pF (including all parasitic capacitances).
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Table 5. OPTICAL CHARACTERISTICS
(Unless otherwise specified, these specifications are for VDD = 3.3 V, TA = 25°C, TINT = 200 ms)
Parameter Test Conditions Symbol Min Typ Max Unit
Irradiance responsivity lp (see Figure 5) Re545 nM
Illuminance responsivity White LED Source:
Ev = 100 lux (see Figure 6)
Rvi100 154 Counts
White LED source:
Ev = 1000 lux (see Figure 6)
Rvi1000 1543
Dark responsivity Ev = 0 lux (see Figure 6) IDARK 0 Counts
Figure 3. AC Characteristics
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TYPICAL CHARACTERISTICS
Figure 4. Spectral Response Figure 5. Illumination Response to Various
Light Sources
WAVELENGTH (nm)
900800700600500400300200
0
0.1
0.3
0.4
0.6
0.7
0.9
1.0
Figure 6. Output Counts vs. Ev Figure 7. Output Counts vs. Temperature
(100 lux)
Ev (lux) TEMPERATURE (°C)
120010008006004002000
0
400
800
1200
1600
2000
6040200−20−40−60
0
0.2
0.4
0.6
0.8
1.0
1.2
Figure 8. Output Counts vs. Angle
(End View, Normalized)
Figure 9. Output Counts vs. Angle
(Side View, Normalized)
OUTPUT COUNTS (Normalized)OUTPUT COUNTS
Incandescent
(2850K)
Fluorescent
(2700K)
White LED
(5600K)
Fluorescent
(5000K)
RATIO
2.01.51.00.50
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0 010 20 30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
−170
−160
−150
−140
−130
−120
−110
−100
−90
−80
−70
−60
−50
−40
−30
−20 −10
Q
END VIEW
1
2
3
6
5
4
TOP VIEW
−90o90o
0.0
0.2
0.4
0.6
0.8
1.0 010 20 30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
−170
−160
−150
−140
−130
−120
−110
−100
−90
−80
−70
−60
−50
−40
−30
−20 −10
Q
SIDE VIEW
TOP VIEW
1
2
3
6
5
4
−90o90o
White LED (5600K)
80 100
VDD = 3.3 V
OUTPUT COUNTS (Normalized to 20°C)
1000
0.2
0.5
0.8
ALS
Human Eye
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TYPICAL CHARACTERISTICS
Figure 10. Output Counts vs. Temperature
(0 lux)
Figure 11. Output Counts vs. Supply Voltage
(100 lux)
TEMPERATURE (°C)
806040200−20−40−60
−2.0
−1.5
−0.5
0
0.5
1.0
1.5
2.0
Figure 12. Supply Current vs. Temperature
(100 lux)
Figure 13. Supply Current vs Supply Voltage
(100 lux)
TEMPERATURE (°C) VDD (V)
806040200−20−40−60
0
10
30
40
60
70
90
100
3.63.43.23.02.82.62.4
0
10
30
40
50
70
90
100
Figure 14. Maximum Value of RP (in kW) as a
function of Bus Capacitance (in pF)
Figure 15. SDA Fall Time (tf)
BUS CAPACITANCE (pF) TIME (s)
4003002001000
0
1.5
3.0
4.5
6.0
7.5
127.5u127.0u126.5u126.0u
0
1
2
3
4
OUTPUT COUNTS (Normalized to 20°C)
IDD (mA)
IDD (mA)
RP(max) (KW)
VDD (V)
3.63.43.23.02.82.62.4
0
0.2
0.4
0.6
0.8
1.0
1.2
OUTPUT COUNTS (Normalized)
RS = 0
20
60
80
100
20
50
80
VDD = 3.3 V
100
−1.0 VDD = 3.3 V
RP = 1 kW
Cb = 400 pF (including all parasitic caps)
tf = 75 ns
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DESCRIPTION OF OPERATION
Ambient Light Sensor Architecture
The NOA1305 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+Cntń(Ik Tint )(eq. 1)
Where:
Ik ≈ 7.7 (for White LED Source)
For example let:
Cnt = 1000
Tint = 200 mS
Intensity of ambient light, IL(in lux):
IL+1000ń(7.7 200 mS ) (eq. 2)
IL = 649 lux
Modes of Operation
The NOA1305 can be placed in any of the following
modes of operation by programming registers over the I2C
bus:
1. Interrupt driven mode
2. Polling mode
3. Power−down mode
In the interrupt driven mode, once the NOA1305 is
configured, no I2C activity is necessary until the ambient
light intensity goes above the value programmed in the
interrupt threshold register. When this occurs, the device
signals an interrupt on the INT pin. Then it is up to the I2C
master host to read the ALS count from the device.
In polling mode, interrupts are typically disabled, but the
NOA1305 continuously takes measurements and the I2C
master host reads out the most recent count whenever it
desires to do so, typically in a timed repeat loop.
In power−down mode, the NOA1305 stops taking
ambient light measurements and powers down most of the
internal circuitry and the INT pin is deactivated. Power is
maintained to preserve the register values (static memory)
and a portion of the I2C remains active to monitor for a
power−on command to the NOA1305.
I2C Interface
The NOA1305 acts as an I2C slave device and supports
single register read and write operations, in addition to block
read and block write operations. All data transactions on the
bus are 8 bits long. Each data byte transmitted is followed by
an acknowledge bit. Data is transmitted with the MSB first.
Figure 16 shows an I2C write operation. Write transactions
begin with the master sending an I2C start sequence
followed by the seven bit slave address (NOA1305 = 0x39)
and the write(0) command bit. The NOA1305 will
acknowledge this byte transfer with an appropriate ACK.
Next the master will send the 8 bit register address to be
written to. Again the NOA1305 will acknowledge reception
with an ACK. Finally, the master will begin sending 8 bit
data segment(s) to be written to the NOA1305 register bank.
The NOA1305 will send an ACK after each byte and
increment the address pointer by one in preparation for the
next transfer. Write transactions are terminated with either
an I2C STOP or with another I I2C START (repeated
START).
788
A[6:0] D[7:0] D[7:0]
WRITE ACK ACK ACK
Device
Address
Register
Address
Register
Data
Start
Condition
Stop
Condition
011 1001 0 0000000000000 0110 00
0x72
Figure 16. I2C Write Command
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Figure 17 shows the most basic I2C read command
sequence sent by the master to the slave device. The
sequence consists of a complete I2C write command which
sets the address pointer in preparation for the I2C read
command since the read command itself does not include a
register address. When reading from a read only data register
in the NOA1305 it is acceptable to write a 0 to the register
in order to update the address pointer, but the 0 does not
actually over−write the value in the data register.
788
A[6:0] D[7:0] D[7:0]
WRITE ACK ACK ACK
Device
Address Register
Address Register
Data
Start
Condition Condition
011 1001 0 0000000000000 0110 00
0x72
788
A[6:0] D[7:0] D[7:0]
READ ACK ACK NACK
Device
Address
Register
Data [A]
Register
Data [A+1]
Start
Condition
Stop
Condition
011 1001 1 0 bbbbbbbbbbbbbbbb 01
0x73
Stop
D[7:0] ACKD[7:0] ACK
Figure 17. I2C Read Command
Once the I2C write command is completed, the master
sends an I2C start sequence followed by the seven bit slave
address (NOA1305 = 0x39) and the read (1) command bit.
The NOA1305 will acknowledge this byte transfer with an
appropriate ACK. The NOA1305 will then begin shifting
out data from the register just addressed. If the master wishes
to receive more data (next register address), it will ACK the
slave at the end of the 8 bit data transmission, and the slave
will respond by sending the next byte, and so on. To signal
the end of the read transaction, the master will send a NACK
bit at the end of a transmission followed by an I2C STOP.
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 15 shows the fall time on SDA in output mode
under maximum load conditions. The measurement set−up
is shown in Figure 18. Figure 14 shows the maximum value
of the pull−up resistor (RP) as a function of the I2C data bus
capacitance.
NOA1305
LED
Pulse
Generator
ADC
SDA
SCL
16−bits
Control INT
ADC
Control
Figure 18. Measurement Set−up
hn
I2C Serial
Interface
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NOA1305 Data Registers
NOA1305 operation is observed and controlled by internal data registers read from and written to via the external I2C
interface. Registers are listed in Table 6. Default values are set on initial power up.
Table 6. NOA1305 DATA REGISTERS (Note 7)
Address Register Type Value (binary) Description Default (binary)
0x00 POWER_CONTROL RW 0000 0000 Power Down 0000 1000
0000 1000 Power On
0000 1001 Test Mode 1 (reserved)
0000 1010 Test Mode 2 (fixed output 0x5555)
0000 1011 Test Mode 3 (fixed output 0xAAAA)
0x01 RESET RW 0001 0000 Reset ALS data. Resets to 0000 0000 0000
0x02 INTEGRATION_TIME RW 0000 0000 800 ms continuous measurement 0000 0010
0000 0001 400 ms continuous measurement
0000 0010 200 ms continuous measurement
0000 0011 100 ms continuous measurement
0000 0100 50 ms continuous measurement
0000 0101 25 ms continuous measurement
0000 0110 12.5 ms continuous measurement
0000 0111 6.25 ms continuous measurement
0x03 INT_SELECT RW 0000 0001 L → H 0000 0011
0000 0010 H → L
0000 0011 Inactive, always H
0x04 INT_THRESH_LSB RW XXXX XXXX Interrupt threshold, least significant bits 0000 0000
0x05 INT_THRESH_MSB RW XXXX XXXX Interrupt threshold, most significant bits 0000 1000
0x06 ALS_DATA_LSB R XXXX XXXX ALS measurement data, least significant bits 0000 0000
0x07 ALS_DATA_MSB R XXXX XXXX ALS measurement data, most significant bits 0000 0000
0x08 DEVICE_ID_LSB R 0001 1001 Device ID value, least significant bits
(1305 decimal, 0x0519 hex)
0001 1001
0x09 DEVICE_ID_MSB R 0000 0101 Device ID value, most significant bits
(1305 decimal, 0x0519 hex)
0000 0101
7. Writing a value other than those specified for registers 0x00, 0x01, 0x02, 0x03 will cause the specified default value to be written instead.
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POWER_CONTROL Register (0x00)
The POWER_CONTROL register is used to power the
device up and down via software control. By default this
device powers up in the power ON mode. To reduce power
consumption, the NOA1305 can be powered down at any
time by writing 0x00 to this register.
To power up the device, use the following write command
sequence:
1. Issue Start command
2. Issue 0x72 (lower seven bits of I2C slave address
0x39 followed by write−bit 0)
3. Issue 0x00 for the POWER_CONTROL register
address
4. Issue 0x08 to put the device in the power on state
5. Issue Stop command
After applying power to the device or after issuing a
power−on command, stable ALS_DATA and INT signal
may not be available for the first three integration times. For
example with a default of 200 ms integration time, the I2C
master should wait at least 600 ms before accessing this
device.
To power down the device, use the following write
command sequence:
1. Issue Start command
2. Issue 0x72 (lower seven bits of I2C slave address
0x39 followed by write−bit 0)
3. Issue 0x00 for the POWER_CONTROL register
address
4. Issue 0x00 to put the device in the power down
state
5. Issue Stop command
After issuing a power−on command, the I2C master
should wait at least 1.5 ms before accessing this device.
The data registers are set to their default values when
power is first applied to the device. However the
power−down and power−on commands do not affect the
values of the data registers.
The test modes provide a useful debugging mode as they
cause the device to output known values in place of the
ALS_DATA values.
RESET Register (0x01)
Software reset is controlled by this register. Setting this
register followed by an I2C_STOP sequence will
immediately reset the NOA1305 to the startup standby state
and clear the ALS_DATA register. However the values of
the other data registers are not affected.
To reset the device, use the following write command
sequence:
1. Issue Start command
2. Issue 0x72 (lower seven bits of I2C slave address
0x39 followed by write−bit 0)
3. Issue 0x01 for the RESET register address
4. Issue 0x10 to reset the device
5. Issue Stop command
After issuing a reset command, the device will reset the
RESET register to 0x00.
INTEGRATION_TIME Register (0x02)
The INTEGRATION_TIME register controls the
integration time of the ambient light sensor which directly
affects the sensitivity.
To set the integration time, use the following write
command sequence:
1. Issue Start command
2. Issue 0x72 (lower seven bits of I2C slave address
0x39 followed by write−bit 0)
3. Issue 0x02 for the INTEGRATION_TIME register
address
4. Issue 0x02 to set the integration time to 200 ms
(for example)
5. Issue Stop command
INT_SELECT Register (0x03)
The INT_SELECT register controls the polarity of the
interrupt pin INT and enables or disables interrupts on that
pin.
To specify low to high transitions on INT to signal an
interrupt, use the following write command sequence:
1. Issue Start command
2. Issue 0x72 (lower seven bits of I2C slave address
0x39 followed by write−bit 0)
3. Issue 0x03 for the INT_SELECT register address
4. Issue 0x01 to specify low to high signaling on INT
5. Issue Stop command
To specify low to high transitions on INT to signal an
interrupt, use the following write command sequence:
1. Issue Start command
2. Issue 0x72 (lower seven bits of I2C slave address
0x39 followed by write−bit 0)
3. Issue 0x03 for the INT_SELECT register address
4. Issue 0x02 to specify high to low signaling on INT
5. Issue Stop command
Disabling interrupts causes the INT pin to be held in the
open−drain or high state. To disable interrupts completely on
the INT pin, use the following write command sequence:
1. Issue Start command
2. Issue 0x72 (lower seven bits of I2C slave address
0x39 followed by write−bit 0)
3. Issue 0x03 for the INT_SELECT register address
4. Issue 0x03 to disable interrupts on INT
5. Issue Stop command
INT_THRESH_LSB and INT_THRES_MSB Registers
(0x04, 0x05)
The INT_THRESH register specifies an ambient light
threshold value for signaling interrupts on the INT pin. The
INT_THRESH register is 16−bits wide to match the 16−bit
ALS_DATA register and is accessed over the I2C bus as two
8−bit registers for the least and most significant bits (LSB
and MSB). On any measurement cycle where the
ALS_DATA intensity count exceeds the INT_THRESH
value, the INT pin will become active and will remain active
until a measurement cycle where the count is less than or
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equal to the threshold (and provided the INT pin is enabled,
see INT_SELECT register).
Changing the INT_THRESH register value can cause the
INT pin to change immediately if the ALS_DATA to
INT_THRESH comparison changes.
Powering down the device will cause the INT pin to
become inactive.
To program a value into the INT_THRESH register, use
the following write command sequence:
1. Issue Start command
2. Issue 0x72 (lower seven bits of I2C slave address
0x39 followed by write−bit 0)
3. Issue 0x04 for the INT_THRES_LSB register
address
4. Issue the 8−bit LSB value
5. Issue Stop command
6. Issue Start command
7. Issue 0x72 (lower seven bits of I2C slave address
0x39 followed by write−bit 0)
8. Issue 0x05 for the INT_THRES_MSB register
address
9. Issue the 8−bit MSB value
10. Issue Stop command
After a power−down and power−on sequence, wait at least
three integration times for the data to stabilize, before
accessing any ALS_DATA values from NOA1305.
ALS_DATA_LSB and ALS_DATA_MSB Registers
(0x06, 0x07)
The ALS_DATA register holds the ambient light intensity
count from the most recent measurement. The ALS_DATA
register is 16−bits wide and is accessed from the I2C bus as
two 8−bit registers for the least and most significant bits
(LSB and MSB).
To read the ALS_DATA register, use the following read
command sequence:
1. Issue Start command
2. Issue 0x72 (lower seven bits of I2C slave address
0x39 followed by write−bit 0)
3. Issue 0x06 for the INT_DATA_LSB register
address
4. Issue Start command
5. Issue 0x73 (lower seven bits of I2C slave address
0x39 followed by read−bit 1)
6. Read the ALS_DATA_LSB byte
7. Read the ALS_DATA_MSB byte
8. Issue Stop command
DEVICE_ID_LSB and DEVICE_ID_MSB Registers
(0x08, 0x09)
The DEVICE_ID register is a pre−programmed register
that describes the device. For the NOA1305, the register
holds the decimal value of 1305 (0x0519). The DEVICE_ID
register is 16−bits wide and is accessed from the I2C bus as
two 8−bit registers for the least and most significant bits
(LSB and MSB).
To read the DEVICE_ID register, use the following read
command sequence:
1. Issue Start command
2. Issue 0x72 (lower seven bits of I2C slave address
0x39 followed by write−bit 0)
3. Issue 0x08 for the DEVICE_ID_LSB register
address
4. Issue Start command
5. Issue 0x73 (lower seven bits of I2C slave address
0x39 followed by read−bit 1)
6. Read the DEVICE_ID_LSB byte
7. Read the DEVICE_ID_MSB byte
8. Issue Stop command
NOA1305
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12
Example Programming Sequence
The following pseudo code configures the NOA1305 ambient light sensor and then runs it in an interrupt driven mode. When
the controller receives an interrupt, it reads the ALS_Data from the device, sets a flag and then waits for the main polling loop
to respond to the ambient light change.
external subroutine I2C_Read_Byte (I2C_Address, Data_Address);
external subroutine I2C_Read_Block (I2C_Address, Data_Start_Address, Count, Memory_Map);
external subroutine I2C_Write_Byte (I2C_Address, Data_Address, Data);
external subroutine I2C_Write_Block (I2C_Address, Data_Start_Address, Count, Memory_Map);
subroutine Initialize_ALS () {
MemBuf[0x00] = 0x08; // POWER_CONTROL assert Power On
MemBuf[0x01] = 0x10; // RESET assert reset
MemBuf[0x02] = 0x02; // INTEGRATION_TIME select 200ms
MemBuf[0x03] = 0x01; // INT_SELECT select Low to High
MemBuf[0x04] = 0xFF; // INT_THRESH_LSB
MemBuf[0x05] = 0x8F; // INT_THRESH_MSB
I2C_Write_Block (I2CAddr, 0x00, 6, MemBuf);
}
subroutine I2C_Interupt_Handler () {
// Retrieve and store the ALS data
ALS_Data_LSB = I2C_Read_Byte (I2CAddr, 0x06);
ALS_Data_MSB = I2C_Read_Byte (I2CAddr, 0x07);
NewALS = 0x01;
}
subroutine main_loop () {
I2CAddr = 0x39;
NewALS = 0x00;
Initialize_ALS ();
loop {
// Do some other polling operations
if (NewALS == 0x01) {
NewALS = 0x00;
// Do some operations with ALS_Data
}
}
}
NOA1305
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13
PACKAGE DIMENSIONS
ÍÍÍ
ÍÍÍ
ÍÍÍ
NOTES:
1. DIMENSIONING AND TOLERANCING PER ASME
Y14.5M, 1994.
2. CONTROLLING DIMENSION: MILLIMETERS.
3. DIMENSION b APPLIES TO PLATED TERMINAL AND
IS MEASURED BETWEEN 0.15 AND 0.30mm FROM
THE TERMINAL TIP.
4. COPLANARITY APPLIES TO THE EXPOSED PAD AS
WELL AS THE TERMINALS.
SEATING
PLANE
D
E
0.10 C
A3
2X
2X
0.10 C
CUDFN6, 2x2
CASE 505AD−01
ISSUE B
DIM MAX
MILLIMETERS
PIN ONE
REFERENCE
0.05 C
0.05 C
7X
A0.10 C
NOTE 3
L
e
D2
E2
b
B
3
6
6X
1
K4
6X
0.05 C
BOTTOM VIEW
MOUNTING FOOTPRINT
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.
A B
TOP VIEW
A
A1
DETAIL A
C
SIDE VIEW
NOTE 4
DETAIL A
END VIEW
d
q
A
A1
b
E2
D
d
E
K
e
L
q
A3
MIN
0.55
0.00
0.18
0.80
---
0.20
0.25
4
0.65
0.05
0.28
1.00
0.10
---
0.35
0.20 REF
10
2.00 BSC
2.00 BSC
0.65 BSC
55
6X
0.52
0.65
PITCH
1.70
2.30
6X
0.28
1.00
1
D2 1.50 1.70
A0.10 CB
A0.10 CB
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