NOA1312
Product Preview
High-Precision Ambient
Light Sensor with Three I2C
Slave Addresses, EEPROM
and Dark Current
Compensation
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Description
The NOA1312 high−precision ambient light sensor (ALS) is
designed for very high accuracy (better than ±5% tolerance) handheld
applications. The device integrates a 16−bit ADC, a 2−wire I2C digital
interface with three pin−selectable I2C slave addresses, internal clock
oscillator, EEPROM and a power down mode. A photopic optical color
filter together with built in dynamic dark current compensation and
precision calibration capability plus 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 NOA1312
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.
Features
• Senses Ambient Light and Provides an Output Count Proportional to
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the Ambient Light Intensity
Human Eye Spectral Response using Photopic Optical Filter
Dynamic Dark Current Compensation
Very High Accuracy (better than ±5% tolerance)
Ev Sensitivity of 5.2 Counts/lux
Three I2C Slave Addresses (0x29, 0x39 and 0x49), Pin Selectable
Less than 240 mA Active Power Consumption in Normal Operation
Ultra−low Quiescent Power Dissipation, less than 100 nA in Power
Down Mode (below 50°C)
Interrupt Signal Notifies Host of Significant Intensity Changes
Internal EEPROM Stores Values to Minimize Programming Time
Register Values Preserved during Power−down Mode
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 0.096 lux to Full Sunlight
Programmable Integration Times
No External Components Required
Built−in 16−bit ADC
I2C Serial Communication Port Supports Standard and Fast Modes
This Device is Pb−Free, Halogen Free/BFR Free, and RoHS
Compliant
CUDFN6
CU SUFFIX
CASE 505AD
PIN ASSIGNMENT
VSS
1
VDD
INT
AD
SCL
SDA
(Top View)
ORDERING INFORMATION
Device
Package
Shipping†
NOA1312CUTAG
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.
Applications
• Saves Display Power in Applications such as:
− Tablets, LED Backlit Displays,
Smart Phones, Netbooks, PDAs,
MP3 Players, GPS
− Video Recorders
This document contains information on a product under development. ON Semiconductor
reserves the right to change or discontinue this product without notice.
© Semiconductor Components Industries, LLC, 2011
November, 2011 − Rev. P0
1
Publication Order Number:
NOA1312/D
NOA1312
Vin = 2.4 to 3.6 V
R1
1k
hv
R2
1k
R3
1k
MCU
6
4
SDA
VDD
SCL 3
C2
2
INT
0.1 m 1
5
AD
VSS
C3
IC1
NOA1312 100 p
C1
10 m
SDA
SCL
INT
VDD,
NC or
VSS
Cb1 Cb2 Cb3
Figure 1. Typical Application Circuit
Cbn not to exceed 250 pF
including all parasitic
capacitances
SDA
I2C Interface
&
Control
ADC
hv
Reference
Diode
Photo
Diode
SCL
INT
AD
EEPROM
&
Charge
Pump
Figure 2. Simplified Block Diagram
Table 1. PIN FUNCTION DESCRIPTION
Pin
Pin Name
Description
1
VSS
Ground pin.
2
INT
Interrupt request to the host. Active−low, open drain output and requires a 1 kW pull−up resistor.
3
SCL
External I2C clock provided by the I2C master. Requires a 1 kW pull−up resistor.
4
SDA
Bi−directional data signal for communication between this device and the I2C master. Requires a 1 kW
pull−up resistor.
5
AD
6
VDD
I2C slave addresses select pin. Selects one of three I2C slave addresses (0x29, 0x39 or 0x49) depending on if this pin is connected to VDD, NC (open) or VSS at power up. This is not a programmable input,
the connection should not be changed after power up.
Power pin.
Table 2. ABSOLUTE MAXIMUM RATINGS
Rating
Symbol
Value
Unit
Input power supply
VDD
4.0
V
Input voltage range
Vin
−0.2 to VDD + 0.2
V
Output voltage range
Vout
−0.2 to VDD + 0.2
V
Digital output current
Io
−10 to 10
mA
Operating Free−Air Temperature Range
TA
−40 to 85
°C
TSTG
−45 to 85
°C
ESD Capability, Human Body Model (Note 1)
ESDHBM
2,000
V
ESD Capability, Charged Device Model (Note 1)
ESDCDM
750 (corner pins), 500 (center pins)
V
ESD Capability, Machine Model (Note 1)
ESDMM
200
V
Storage Temperature
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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NOA1312
Table 3. OPERATING RANGES
Rating
Symbol
Min
Typ
Max
Unit
Power supply voltage
VDD
2.4
3.0
3.6
V
Power supply current
IDD
140
240
mA
IDDqs
12
800
nA
Quiescent supply current (Note 3)
Low level input voltage
VIL
−0.2
0.3 VDD
V
High level input voltage (Note 4)
VIH
0.7 VDD
VDD + 0.2
V
Hysteresis of SCL & SDA Schmitt trigger inputs (VDD > 2 V)
Vhys
0.05 VDD
Low level output voltage (open drain) at 3 mA sink current (SDA, INT)
VOL
0
0.4
V
Output low current (SDA, INT)
IOL
3
−
mA
Output fall time from VIHmin to VILmax with a bus capacitance, Cb from
10 pF to 250 pF (Note 4)
tof
−
250
ns
Input current of IO pin with an input voltage between 0.1 VDD and 0.9 VDD
II
−10
10
mA
10
pF
85
°C
Capacitance for IO pin (Note 4)
Cb
Operating free−air temperature range
TA
V
−
−40
3. Current dissipation when in Power Down mode. 800 nA power down current at 85°C (see Figure 14).
4. Cb = capacitance of one bus line, maximum value including all parasitic capacitances should be less than 250 pF.
Table 4. ELECTRICAL CHARACTERISTICS
(Unless otherwise specified, these specifications apply over 2.4 V < VDD < 3.6 V, −40°C < TA < 85°C, 10 pF < Cb < 100 pF) (Note 5)
Standard Mode
Fast Mode
Symbol
Min
Max
Min
Max
Unit
fSCL
10
100
100
400
kHz
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 repeated START condition
tSUSTA
4.7
−
SDA Data hold time
tHDDAT
0
SDA Data set−up time
tSUDAT
250
Rise time of both SDA and SCL (input signals) (Note 6)
tr
Fall time of both SDA and SCL (input signals) (Note 6)
Parameter
SCL clock frequency
Hold time after repeated start condition.
After this period, the first clock pulse is generated.
Set−up time for STOP condition
Bus free time between STOP and START condition
0.6
−
3.45
0
0.9
mS
−
100
−
nS
5
1000
20 + 0.1Cb
300
nS
tf
5
300
20 + 0.1Cb
300
nS
tSUSTO
4.0
−
0.6
−
mS
tBUF
4.7
−
1.3
−
mS
mS
Capacitive load for each bus line
Cb
−
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
Parameter
Internal Oscillator Frequency
Symbol
Typ
Typ
Unit
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 250 pF (including all parasitic capacitances). The maximum
tf for the SDA and SCL bus lines (300 ns) is longer than the specified maximum tof for the output stages (250 ns). This allows series protection
resistors (Rs) to be connected between the SDA/SCL pads and the SDA/SCL bus lines without exceeding the maximum specified tf.
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NOA1312
Table 5. OPTICAL CHARACTERISTICS (Unless otherwise specified, these specifications are for VDD = 3.0 V, TA = 25°C)
Parameter
Test Conditions
Symbol
Irradiance responsivity
lp (see Figure 4)
Trimmed response
White LED light source, Ev = 100 lux,
Tint = 200 ms (see Figure 7)
Rv_trim
Dark response
Ev = 0 lux, Tint = 400 ms, VDD = 2.4 to
3.6 V,−40_C to 85_C
Rv_dark
Illuminance responsivity
White LED light source, Ev = 12,603 lux,
Tint = 200 ms
(see Figure 5, Figure 6, Note 7)
Rv_max
Counts vs Vdd
Ev = 100 lux, Tint = 200 ms, VDD = 2.4 to
3.6 V, relative to VDD = 3.0 V
dC/dVDD
Counts vs Temperature
(−40°C to 0°C)
Ev = 100 lux, Tint = 200 ms, VDD = 3.0 V,
−40°C to 0°C, relative to room temperature
(25°C)
Counts vs Temperature
(0°C to 85°C)
Ev = 100 lux, Tint = 200 ms, VDD = 3.0 V,
0°C to 85°C, relative to room temperature
(25°C)
Linearity (Low Ev)
Min
Re
Typ
Max
550
494
Unit
nm
520
546
Counts
0
1
Counts
65,535
Counts
−5
5
%
dC/dTlow
−20
20
%
dC/dThigh
−5
5
%
White LED light source, Ev = 0 − 15 lux,
Tint = 200 ms
Llow
(5.2*Ev )−5
(5.2*Ev)+2
Counts
Linearity (High Ev)
White LED light source, Ev = 15 − 16,250
lux, Tint = 200 ms (Note 8)
Lhigh
−5
3.5
%
Count stability
Ev = 100 lux, Tint = 200 ms, VDD = 3.0 V
(Note 9)
dC/dt
−1
1
%
Trimming range
Ev = 100 lux, Tint = 200 ms, −37% to
+65%, VDD = 2.4 to 3.6 V, −40°C to 85°C
(Note 10)
TRIMrange
315
825
Counts
7. The maximum count that can be accumulated in a 16−bit register is 65,535.
8. Linearity (high Ev) is estimated using the following formula:
Linearity (High Ev) = ((Counts(n) – Ideal_counts(n))/ Ideal_counts(n)))* 100
where:
n is an Ev value between 0 lux and 16,250 lux
Ideal_counts (at any Ev): 5.2 counts/lux (Tint = 200 ms)
Linearity values shown above after the final trimming.
9. Count stability is measured over a duration of 5 minutes using a stable white LED at Ev = 100 lux, VDD = 3.0 V, TA = 25°C
10. Output counts prior to trimming: low counts = 520/1.65, high counts = 520/0.63.
Figure 3. AC Characteristics
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NOA1312
TYPICAL CHARACTERISTICS
OUTPUT COUNTS (Normalized %)
100
90
5000 K
Fluorescent
5600 K
White LED
2700 K
Fluorescent
2850 K
Incandescent
80
70
60
50
40
30
20
10
0
Human Eye
200 300
400
ALS
500
600
700
800
900
0
1000
0.5
1.0
1.5
2.0
WAVELENGTH (nm)
RATIO
Figure 4. Spectral Response (Normalized)
Figure 5. Light Source Dependency
(Normalized to Fluorescent Light,
Tint = 200 ms)
100 k
1000
900
OUTPUT COUNTS
OUTPUT COUNTS
10 k
1k
100
10
800
700
600
Trim to 520 Counts at 100 lux
500
400
300
1
0.1
1
−110
100
1k
200
10 k
0
50
100
150
200
Ev (lux)
TRIM CODES
Figure 6. Output Counts vs. Ev, 0−2000 lux
(Tint = 200 ms)
Figure 7. Output Counts and Trim Codes
(100 lux, VDD = 3.0 V, Tint = 200 ms)
−10
0
−20 100
−30
90
80
−40
70
−50
60
−60
50
40
−70
30
20
−80
10
0
−90
−100
10
10 20
30
−10
0
−20 100
−30
90
80
−40
70
−50
60
−60
50
40
−70
30
20
−80
10
0
−90
40
50
60
70
80
90
100
110
Q
−100
−110
10 20
30
250
40
50
60
70
80
90
100
110
Q
END VIEW
−120
120 SIDE VIEW
−90°
1
6 90°
6 5 4
130
−130
−130
130
2
5
140
−90°
90°
−140
−140
140
3
4
150
150
−150
−150
1 2 3
160
160
−160
−160−170
TOP VIEW
−170 180 170
TOP VIEW
180 170
−120
120
Figure 8. Output Counts vs. Angle
(End View, Normalized)
Figure 9. Output Counts vs. Angle
(Side View, Normalized)
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NOA1312
TYPICAL CHARACTERISTICS
1
600
580
OUTPUT COUNTS
OUTPUT COUNTS
560
0
−20
0
20
40
60
520
500
480
460
VDD = 3.6 V
VDD = 2.4 V
440
VDD = 3.6 V
VDD = 2.4 V
−1
−40
540
420
400
−40
80
−20
0
20
40
60
80
TEMPERATURE (°C)
TEMPERATURE (°C)
Figure 10. Output Counts at 0 lux vs.
Temperature (Tint = 400 ms)
Figure 11. Output Counts at 100 lux vs.
Temperature (Tint = 200 ms)
2
600
OUTPUT COUNTS
OUTPUT COUNTS
560
1
520
480
440
0
2.0
2.5
3.0
3.5
400
4.0
2.0
2.5
3.0
3.5
4.0
VDD (V)
VDD (V)
Figure 12. Output Counts at 0 lux vs. Supply
Voltage (Tint = 400 ms)
Figure 13. Output Counts at 100 lux vs. Supply
Voltage (Tint = 200 ms)
700
200
VDD = 3.6 V
VDD = 2.4 V
600
160
IDD (mA)
IDD (nA)
500
400
300
120
80
200
0
−40
VDD = 3.6 V
VDD = 2.4 V
40
100
−20
0
20
40
60
0
−40
80
−20
0
20
40
60
80
TEMPERATURE (°C)
TEMPERATURE (°C)
Figure 14. Supply Current in Power Down
Mode vs. Temperature
(100 lux, Tint = 200 ms)
Figure 15. Supply Current vs. Temperature
(100 lux, Tint = 200 ms)
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NOA1312
100
200
80
160
60
120
IDD (mA)
IDD (nA)
TYPICAL CHARACTERISTICS
40
40
20
0
80
2.0
2.5
3.0
3.5
0
4.0
2.0
2.5
3.0
3.5
4.0
VDD (V)
VDD (V)
Figure 16. Supply Current in Power Down
Mode vs. Supply Voltage
(100 lux, Tint = 200 ms)
Figure 17. Supply Current vs. Supply Voltage
(100 lux, Tint = 200 ms)
CL = 250 pF (including all parasitic capacitances)
Rp = 1 K
Fall time tf = 36 ns
Figure 18. SDA and INT Fall Time (tf)
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NOA1312
DESCRIPTION OF OPERATION
Ambient Light Sensor Architecture
In the interrupt driven mode, once the NOA1312 is
configured, no I2C activity is necessary until the ambient
light intensity goes above the value programmed in the
interrupt threshold register (see INT_SELECT register 0x03
for details). 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_DATA count from the device.
In polling mode, interrupts are typically disabled, but the
NOA1312 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 NOA1312 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 NOA1312.
The NOA1312 employs a sensitive photo diode fabricated
in ON Semiconductor’s standard CMOS process
technology. The major components of this sensor are as
shown Figure 2. The photons which are to be detected pass
through the photopic 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 and
exhibits excellent IR rejection. The photo response of this
sensor is as shown in Figure 4.
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 stored in the ALS_DATA register where it can be read by
the I2C interface.
Sensor Accuracy Trim
Highly accurate ambient light intensity reading can be
obtained from the NOA1312 by following a simple
trimming procedure which stores the trim value in the
EEPROM memory. This not only enables more accurate
readings, but also provides a way to match readings between
devices. Matching to better than 2% is achievable when
devices share a common power supply and thermal
environment.
The NOA1312 uses a type of binary weighted trim code
approach which allows the output count to be calibrated to
a known light intensity. The factory default code stored in
the EEPROM is shown in Table 8. Figure 7 shows the
trimming of the output counts when Ev = 100 lux. The
trimming operation is performed by writing an 8−bit code in
the range of 0 to 255 (0x00 to 0xFF) to the EEPROM
OUTPUT_TRIM register 0x16. Changes to the trim register
are reflected in real time on the output value of the device.
As indicated in Table 5, the trimming range is from 315
(when trim code is 0xFF) to 825 (when trim code is 0x00).
One possible trimming algorithm is to perform a binary
search starting with trim code 0x00, refining the search to
find a trim code providing 520 counts at Ev=100 lux within
the desired accuracy.
I2C Interface
The NOA1312 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.
The I2C bus address of this device can be 0x29, 0x39 or
0x49, depending on the state of AD pin. When AD is
connected to VDD, the address is 0x29. When AD is not
connected (floating), the address is 0x39. When AD is
connected to VSS, the address is 0x49. The AD connection
must not be changed after power is applied to the device.
Figure 19 shows an I2C write operation. Write
transactions begin with the master sending an I2C start
sequence followed by the seven bit slave address (e.g. 0x29)
and the write(0) command bit. The NOA1312 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 NOA1312 will acknowledge reception
with an ACK. Finally, the master will begin sending 8−bit
data segment(s) to be written to the NOA1312 register bank.
The NOA1312 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 I2C START (repeated START).
Modes of Operation
The NOA1312 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
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NOA1312
Register
Register
Device
Address
Address
Data
A[6:0] WRITE ACK D[7:0] ACK D[7:0]
ACK
010 1001 0
0 0000 0000 0 0001 0000 0
0x52
7
8
8
Start
Condition
Figure 19.
I2C
Stop
Condition
Write Command
Register
Register
Device
Address
Address
Data
A[6:0] WRITE ACK D[7:0] ACK D[7:0]
ACK
010 1001 0
0 0000 0110 0 0000 0000 0
0x52
7
8
8
Start
Condition
Stop
Condition
Register
Register
Device
Address
Data [A]
Data [A+1]
A[6:0] READ ACK D[7:0] ACK D[7:0] NACK
0 bbbb bbbb 0 bbbb bbbb 1
010 1001 1
0x53
7
8
8
Start
Condition
Figure 20. I2C Read Command
Figure 20 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 NOA1312 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.
Once the I2C write command is completed, the master
sends an I2C start sequence followed by the seven bit slave
address (e.g. 0x29) and the read(1) command bit. The
NOA1312 will acknowledge this byte transfer with an
appropriate ACK. The NOA1312 will then begin shifting
Stop
Condition
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 18 shows the fall time on SDA in output mode
under maximum load conditions. The measurement set−up
is shown in Figure 21.
SDA
ADC
LED
hv
Pulse
Generator
I2C Interface
&
Control
EEPROM
&
Charge
Pump
NOA1312
Figure 21. Measurement Set−up
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SCL
INT
AD
NOA1312
NOA1312 I2C Slave Address
Should it be necessary, the address can be changed by
following this procedure:
1. Disconnect power from the device
2. Change the AD connection to the desired level as
shown in Table 6.
3. Reconnect power to the device.
Once power is applied to this device, any change in the
connection to the AD pin may cause unpredictable results.
The NOA1312 I2C address is selected by connecting the
AD pin as shown in Table 6.
Table 6. I2C SLAVE ADDRESS TABLE
AD Pin
I2C Slave Address
VDD
0x29
NC (not connected)
0x39
VSS
0x49
NOA1312 Data Registers
NOA1312 operation is observed and controlled by
internal data registers read from and written to via the
external I2C interface. Registers are listed in Table 7.
Default values are set on initial power up.
The AD pin is not programmable. The connection to AD
should be stable before applying power to the device. The
device sets the I2C slave address when power is applied. For
the case where the AD pin is not connected, adding a small
100 pF decoupling capacitor is recommended to provide a
stable state.
Table 7. NOA1312 DATA REGISTERS
Register
Address
Register
Type
Value
(binary)
Description
EEPROM
Address
Default
(binary)
0x00
POWER_CONTROL
RW
0000 0000
Power Down
0x10
0000 0000
0001 0000
Power On
0x01
RESET
RW
0011 0000
Reset ALS data to 0x0000
0x11
0000 0000
0x02
INTEGRATION_TIME
RW
1001 0000
400 ms continuous measurement
0x12
1001 0001
1001 0001
200 ms continuous measurement
1010 0000
100 ms continuous measurement
1010 0001
50 ms continuous measurement
1011 0000
20 ms continuous measurement
1011 0001
2 ms continuous measurement
0000 0001
L→H
0x13
0000 0011
0000 0010
H→L
0000 0011
Inactive (H Keeper)
0x03
INT_SELECT
RW
0x04
INT_THRESH_LSB
RW
XXXX XXXX
Interrupt threshold, least significant bits
0x14
0000 0000
0x05
INT_THRESH_MSB
RW
XXXX XXXX
Interrupt threshold, most significant bits
0x15
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
XXXX XXXX
Device ID value, least significant
0x18
0000 0000
0x09
DEVICE _ID_MSB
R
XXXX XXXX
Device ID value, most significant bits
0x19
0000 0000
0x0A
EEPROM_RDWR_
REG_ADDRESS
RW
XXXX XXXX
Address of EEPROM register to be
read or written to (see Table 8)
−
0000 0000
0x0B
EEPROM _CONTROL_
STATUS
RW
XXXX XXXX
EEPROM read/write operation control
(see Table 10)
−
0000 0000
0x10 to
0x19
Memory Mapped
EEPROM Registers
EEPROM registers (see Table 8)
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10
NOA1312
POWER_CONTROL Register (0x00)
INTEGRATION_TIME Register (0x02)
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 down mode. To reduce power
consumption, the NOA1312 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 0x52 (lower seven bits of I2C slave address
0x29 followed by write−bit 0) – the write address
could be 0x52 (0x29), 0x72 (0x39) or 0x92 (0x49)
3. Issue 0x00 for the POWER_CONTROL register
address
4. Issue 0x10 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 0x52 (lower seven bits of I2C slave address
0x29 followed by write−bit 0) – the write address
could be 0x52 (0x29), 0x72 (0x39) or 0x92 (0x49)
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−down command, the I2C master
should wait at least 1.5 ms before accessing this device.
The data registers are set to the values stored in the
EEPROM 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 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 0x52 (lower seven bits of I2C slave address
0x29 followed by write−bit 0) – the write address
could be 0x52 (0x29), 0x72 (0x39) or 0x92 (0x49)
3. Issue 0x02 for the INTEGRATION_TIME register
address
4. Issue 0x91 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 0x52 (lower seven bits of I2C slave address
0x29 followed by write−bit 0) – the write address
could be 0x52 (0x29), 0x72 (0x39) or 0x92 (0x49)
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 high to low transitions on INT to signal an
interrupt, use the following write command sequence:
1. Issue Start command
2. Issue 0x52 (lower seven bits of I2C slave address
0x29 followed by write−bit 0) – the write address
could be 0x52 (0x29), 0x72 (0x39) or 0x92 (0x49)
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 on the INT
pin, use the following write command sequence:
1. Issue Start command
2. Issue 0x52 (lower seven bits of I2C slave address
0x29 followed by write−bit 0) – the write address
could be 0x52 (0x29), 0x72 (0x39) or 0x92 (0x49)
3. Issue 0x03 for the INT_SELECT register address
4. Issue 0x03 to disable interrupts on INT
5. Issue Stop command
RESET Register (0x01)
Software reset is controlled by this register. Setting this
register followed by an I2C_STOP sequence will
immediately reset the NOA1312 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 0x52 (lower seven bits of I2C slave address
0x29 followed by write−bit 0) – the write address
could be 0x52 (0x29), 0x72 (0x39) or 0x92 (0x49)
3. Issue 0x01 for the RESET register address
4. Issue 0x30 to reset the device
5. Issue Stop command
After issuing a reset command, the device will reset the
RESET register to 0x00.
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
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11
NOA1312
DEVICE_ID_LSB and DEVICE_ID_MSB Registers
(0x08, 0x09)
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
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 0x52 (lower seven bits of I2C slave address
0x29 followed by write−bit 0) – the write address
could be 0x52 (0x29), 0x72 (0x39) or 0x92 (0x49)
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 0x52 (lower seven bits of I2C slave address
0x29 followed by write−bit 0) – the write address
could be 0x52 (0x29), 0x72 (0x39) or 0x92 (0x49)
8. Issue 0x05 for the INT_THRES_MSB register
address
9. Issue the 8−bit MSB value
10. Issue Stop command
The DEVICE_ID registers hold the ID number for this
device. This ID number could be changed at any time by
writing appropriate ID number to the EEPROM registers
0x18 and 0x19. 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 0x52 (lower seven bits of I2C slave address
0x29 followed by write−bit 0) – the write address
could be 0x52 (0x29), 0x72 (0x39) or 0x92 (0x49)
3. Issue 0x08 for the DEVICE_ID_LSB register
address
4. Issue Start command
5. Issue 0x53 (lower seven bits of I2C slave address
0x29 followed by read−bit 1) – the read address
could be 0x53 (0x29), 0x73 (0x39) or 0x93 (0x49)
6. Read the DEVICE_ID_LSB byte
7. Read the DEVICE_ID_MSB byte
8. Issue Stop command
NOA1312 EEPROM Registers
The EEPROM registers are listed in Table 8. The defaults
values are set at the factory and will retain their values until
modified by the user. They retain their values even when the
device is not powered.
ALS_DATA_LSB and ALS_DATA_MSB Registers (0x06,
0x07)
Table 8. EEPROM REGISTERS
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 0x52 (lower seven bits of I2C slave address
0x29 followed by write−bit 0) – the write address
could be 0x52 (0x29), 0x72 (0x39) or 0x92 (0x49)
3. Issue 0x06 for the INT_DATA_LSB register
address
4. Issue Start command
5. Issue 0x53 (lower seven bits of I2C slave address
0x29 followed by read−bit 1) – the read address
could be 0x53 (0x29), 0x73 (0x39) or 0x93 (0x49)
6. Read the ALS_DATA_LSB byte
7. Read the ALS_DATA_MSB byte
8. 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 NOA1312.
EEPROM
Address
Register
Type
Factory
Default Value
(binary)
0x10
POWER_CONTROL
RW
0000 0000
0x11
RESET_ALS_DATA
RW
0000 0000
0x12
INTEGRATION_TIME
RW
1001 0001
0x13
INT_SELECT
RW
0000 0011
0x14
INT_THRESH_LSB
RW
0000 0000
0x15
INT_THRESH_MSB
RW
0000 1000
0x16
OUTPUT_TRIM
RW
0101 1101
0x17
For future use
RW
XXXX XXXX
0x18
DEVICE_ID_LSB
RW
0000 0000
0x19
DEVICE_ID_MSB
RW
0000 0000
EEPROM_RDWR_REG_ADDRESS Register (0x0A)
The EEPROM_RDWR_REG_ADDRESS register
specifies the address of an EEPROM register to be read or
written to and is used in conjunction with the
EEPROM_CONTROL_STATAUS register (0x0B) to effect
read and write operations with the EEPROM.
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12
NOA1312
The EEPROM enables the NOA1312 to retain register
values even when fully powered down, facilitating a quick
and simple power on sequence. Table 8 shows the EEPROM
registers and their values as shipped from the factory. During
power up, the values in the EEPROM registers are
automatically transferred to the I2C registers as specified in
Table 9. EEPROM register values are not automatically
updated during power down and must be explicitly updated
with a write operation as described below.
EEPROM register address 0x16 contains an 8−bit
OUTPUT_TRIM value. Writing to the OUTPUT_TRIM
register will change the output count value in real time.
EEPROM register address 0x17 is reserved for future use.
Table 9. NOA1312 Data Registers Stored in EEPROM
I2C Register
Address
EEPROM
Register Address
0x00
0x10
POWER_CONTROL
0x01
0x11
RESET_ALS_DATA
0x02
0x12
INTEGRATION_TIME
0x03
0x13
INT_SELECT
0x04
0x14
INT_THRESH_LSB
0x05
0x15
INT_THRESH_MSB
none
0x16
OUTPUT_TRIM
none
0x17
For future use
0x08
0x18
DEVICE_ID_LSB
0x09
0x19
DEVICE_ID_MSB
Register Name
Table 10. EEPROM_CONTROL_STATUS REGISTER BITS
Bit
Description
0
Write to EEPROM – when this bit is set to ‘1’, the register whose address is written in the EEPROM_RDWR_REG_ADDRESS
register (located at address 0x0A) is written to the EEPROM. The data to be written to EEPROM should be written to registers
0x10 – 0x19 before writing a ‘1’ to this bit.
1
EEPROM write complete flag – after bit[0] of this register is written with a value of ‘1’, the EEPROM write operation is started.
After the EEPROM write operation is complete, bit[1] is set to ‘1’ and bit[0] is cleared to ‘0’.
2
Read from EEPROM – when this bit is set to ‘1’, the register whose address is written in the EEPROM_RDWR_REG_ADDRESS register (located at address 0x0A) is read from EEPROM. The data read from EEPROM is placed in the appropriate
register 0x10 – 0x19.
3
EEPROM read complete flag – after bit[2] of this register is written with a value of ‘1’, the EEPROM read operation is started.
After the EEPROM read operation is complete, bit[3] is set to ‘1’ and bit[2] is cleared to ‘0’.
4−7
Reserved
7. Issue 0x52 (lower seven bits of I2C slave address
0x29 followed by write−bit 0) – the write address
could be 0x52 (0x29), 0x72 (0x39) or 0x92 (0x49)
8. Issue 0x0B for the
EEPROM_CONTROL_STATUS register address
9. Issue 0x01 value to initiate an EEPROM write
operation
10. Issue Stop command.
11. Wait 15 ms for the EEPROM write operation to
complete
12. Issue Start command
13. Issue 0x52 (lower seven bits of I2C slave address
0x29 followed by write−bit 0) – the write address
could be 0x52 (0x29), 0x72 (0x39) or 0x92 (0x49)
14. Issue 0x0B for the
EEPROM_CONTROL_STATUS register address
15. Issue Start command
16. Issue 0x53 (lower seven bits of I2C slave address
0x29 followed by read−bit 1) – the read address
could be 0x53 (0x29), 0x73 (0x39) or 0x93 (0x49)
17. Read the EEPROM_CONTROL_STATUS byte
18. Issue Stop command
19. If the EEPROM_CONTROL_STATUS byte
equals 0x02 the write is complete, otherwise go to
step 12.
EEPROM_CONTROL_STATUS Register (0x0B)
The EEPROM_CONTROL_STATUS register is used to
effect reads and writes to the EEPROM register specified in
EEPROM_RDWR_REG_ADDRESS. Individual control
and status register bits are used to initiate reads and writes
and to indicate when the operation is complete. Table 10
shows the register bits and their values.
For example, to write the DEVICE_ID_LSB value to the
EEPROM, write the DEVICE_ID_LSB to register 0x18.
Read back register 0x18 to verify the write and then transfer
the data to the EEPROM with the following write command
sequence:
1. Issue Start command
2. Issue 0x52 (lower seven bits of I2C slave address
0x29 followed by write−bit 0) – the write address
could be 0x52 (0x29), 0x72 (0x39) or 0x92 (0x49)
3. Issue 0x0A for the
EEPROM_RDWR_REG_ADDRESS register
address
4. Issue 0x18 for the EEPROM DEVICE_ID_LSB
register address to be read
5. Issue Stop command
6. Issue Start command
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13
NOA1312
To write the DEVICE_ID_MSB value to the EEPROM,
the above sequence must be repeated substituting the MSB
register address values.
To read the DEVICE_ID_LSB value from the EEPROM,
use the following read command sequence:
1. Issue Start command
2. Issue 0x52 (lower seven bits of I2C slave address
0x29 followed by write−bit 0) – the write address
could be 0x52 (0x29), 0x72 (0x39) or 0x92 (0x49)
3. Issue 0x0A for the
EEPROM_RDWR_REG_ADDRESS register
address
4. Issue 0x18 for the EEPROM DEVICE_ID_LSB
register address to be read
5. Issue Stop command
6. Issue Start command
7. Issue 0x52 (lower seven bits of I2C slave address
0x29 followed by write−bit 0) – the write address
could be 0x52 (0x29), 0x72 (0x39) or 0x92 (0x49)
8. Issue 0x0B for the
EEPROM_CONTROL_STATUS register address
9. Issue 0x04 value to initiate an EEPROM read
operation
10. Issue Stop command.
11. Wait 3 ms for the EEPROM read operation to
complete
12. Issue Start command
13. Issue 0x52 (lower seven bits of I2C slave address
0x29 followed by write−bit 0) – the write address
could be 0x52 (0x29), 0x72 (0x39) or 0x92 (0x49)
14. Issue 0x0B for the
EEPROM_CONTROL_STATUS register address
15. Issue Start command
16. Issue 0x53 (lower seven bits of I2C slave address
0x29 followed by read−bit 1) – the read address
could be 0x53 (0x29), 0x73 (0x39) or 0x93 (0x49)
17. Read the EEPROM_CONTROL_STATUS byte
18. Issue Stop command
19. If the EEPROM_CONTROL_STATUS byte
equals 0x08 proceed to the next step, otherwise go
to step 12.
20. Issue Start command
21. Issue 0x52 (lower seven bits of I2C slave address
0x29 followed by write−bit 0) – the write address
could be 0x52 (0x29), 0x72 (0x39) or 0x92 (0x49)
22. Issue 0x18 for the EEPROM DEVICE_ID_LSB
register address
23. Issue Start command
24. Issue 0x53 (lower seven bits of I2C slave address
0x29 followed by read−bit 1) – the read address
could be 0x53 (0x29), 0x73 (0x39) or 0x93 (0x49)
25. Read the DEVICE_ID_LSB byte
26. Issue Stop command
To read the DEVICE_ID_MSB value from the EEPROM,
the above sequence must be repeated substituting the MSB
register address values.
OUTPUT_TRIM Register (0x16)
EEPROM Register Address 0x16 contains 8−bits of
output trim covering the range of 0x00 to 0xFF (0 to 255).
Table 11 shows the minimum, default and maximum trim
available.
Table 11. OUTPUT_TRIM REGISTER VALUES
Input Code
Trim Gain
0000 0000
165%
0101 1101
100%
1111 1111
63%
Changes to the trim register are reflected in real time on
the output value of the device.
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14
NOA1312
Example Programming Sequence
The following pseudo code configures the NOA1312 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
external
external
external
subroutine
subroutine
subroutine
subroutine
I2C_Read_Byte (I2C_Address, Data_Address);
I2C_Read_Block (I2C_Address, Data_Start_Address, Count, Memory_Map);
I2C_Write_Byte (I2C_Address, Data_Address, Data);
I2C_Write_Block (I2C_Address, Data_Start_Address, Count, Memory_Map);
subroutine Initialize_ALS () {
MemBuf[0x00] = 0x10;
// POWER_CONTROL assert Power On
MemBuf[0x01] = 0x30;
// RESET assert reset
MemBuf[0x02] = 0x91;
// 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 = 0x29;
NewALS = 0x00;
Initialize_ALS ();
loop {
// Do some other polling operations
if (NewALS == 0x01) {
NewALS = 0x00;
// Do some operations with ALS_Data
}
}
}
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15
NOA1312
PACKAGE DIMENSIONS
CUDFN6, 2x2
CASE 505AD−01
ISSUE B
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.
0.10 C
2X
D
A B
2X
PIN ONE
REFERENCE
ÍÍÍ
ÍÍÍ
ÍÍÍ
d
E
A
DIM
A
A1
A3
b
D
D2
d
E
E2
e
K
L
q
A1
DETAIL A
TOP VIEW
DETAIL A
0.05 C
7X
q
0.10 C
A3
0.05 C
NOTE 4
C
SIDE VIEW
SEATING
PLANE
END VIEW
MOUNTING FOOTPRINT
0.10 C A
6X
MILLIMETERS
MIN
MAX
0.55
0.65
0.05
0.00
0.20 REF
0.28
0.18
2.00 BSC
1.50
1.70
--0.10
2.00 BSC
0.80
1.00
0.65 BSC
0.20
--0.35
0.25
45
10 5
6X
1.70
B
0.52
D2
L
1
3
1.00
E2
0.10 C A
6
K
4
e
6X
B
1
b
0.10 C A
BOTTOM VIEW
2.30
0.05 C
B
0.65
PITCH
NOTE 3
6X
0.28
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
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NOA1312/D