TMD3782
Datasheet - Mar. 2013 - V2
Color Light-To-Digital Converter with Proximity Sensing
General Description
The TMD3782x device will perform color temperature
measurement, ambient light sensing (ALS) and proximity
detection with background light rejection. The device detects
light intensity under a variety of lighting conditions and through a
variety of attenuation materials, including dark glass. The
proximity detection feature allows a large dynamic range of
operation for accurate distance detection, such as in a cell phone
when the user positions the phone close to their ear. IR LED sink
current is factory trimmed to provide consistent proximity
response without requiring customer calibrations. An internal
state machine provides the ability to put the device into a low power
state between proximity and RGBC measurements providing very
low average power consumption.
The color sensing feature is useful in applications such as
backlight control, solid state lighting, reflected LED color
sampler, or fluorescent light color temperature detection. The
integrated IR blocking filter makes this device an excellent
ambient light sensor, color temperature monitor, and general
purpose color sensor.
Figure TMD3782 – 1:
Key Benefits and Features
Benefit
Feature
RGB, Ambient Light Sensor (ALS) and Proximity Support
• Power Management Features
• I
2
C Fast Mode Interface Compatible
• Integral IR LED
• Small 8 lead optical module
• UV / IR blocking filters
• Programmable Gain & Integration Time
• 1,000,000:1 Dynamic Range
Circular Segmented RGBC Photodiode
Very High Sensitivity
• Background Ambient Light Rejection
• Factory Trimmed, Consistent Response
• Programmable Current Sink for IR LED Drive
Single Device Integrated Optical Solution
Color Temperature and Ambient Light
Sensing
Equal Response to 360º Incident Light
Ideal for Operation Behind Dark Glass
Proximity Detection with Integrated IR LED
Datasheet - Mar. 2013 - V2
TMD3782 – 1
Applications
The TMD3782 applications include:
•
•
•
•
•
•
Ambient Light Sensing
Color Temperature Sensing
Cell Phone Touch Screen Disable
Mechanical Switch Replacement
Industrial Process Control
Medical Diagnostics
Figure TMD3782 – 2:
Block Diagram
TMD3782 – 2
Datasheet - Mar. 2013 - V2
Detailed Description
The TMD3782 is a digital color light sensor device containing
four analog-to-digital converters (ADCs) that integrate currents
from photodiodes. Multiple photodiode segments for red, green,
blue, and clear are geometrically arranged to reduce the reading
variance as a function of the incident light angle. Integration of
all color sensing channels occurs simultaneously. Upon
completion of the conversion cycle, the result is transferred to the
corresponding data registers. The transfers are double-buffered to
ensure that the integrity of the data is maintained.
Communication with the device is accomplished through a fast
(up to 400 kHz), two-wire I
2
C serial bus for easy connection to
a microcontroller or embedded controller.
The TMD3782 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 a clear channel or proximity conversion
equals or exceeds either an upper or lower threshold. In
addition, a programmable interrupt persistence feature allows
the user to determine how many consecutive s a m p l e s m u s t
e q u a l o r exceed the threshold to trigger an interrupt.
Interrupt thresholds and persistence settings are configured
independently for both the clear channel and proximity sensors.
Proximity detection is done using a dedicated proximity
photodiode centrally located beneath an internal lens, an internal
LED, and a driver circuit. The driver circuit requires no external
components and is trimmed to provide a calibrated proximity
response. Customer calibrations are usually not required. The
number of proximity LED pulses can be programmed from 1 to 255
pulses, providing a 2000:1 contiguous dynamic range.
Background ambient light is subtracted from the proximity
reading to improve accuracy in all lighting conditions.
A state machine controls the functionality. Enabling bits
independently determine whether the Proximity, Wait or RGBC
/ ALS functions are performed. Average power consumption is
managed via control of variable endurance low power wait
cycles. Once initiated the state machine will run continuously
until disabled.
Datasheet - Mar. 2013 - V2
TMD3782 – 3
Pin Assignment
T
he TMD3782 pin assignments are described below.
Figure TMD3782 – 3:
Pin Diagram
Package Module - 8 (Top View)
Package drawing is not to scale.
Figure TMD3782 – 4:
Pin Description
Pin Number
1
2
3
4
5
6
7
8
Pin Name
V
DD
SCL
GND
LEDA
LEDK
LDR
INT
SDA
Typ
PWR
I
GND
PWR
-
-
O
I/O
Supply voltage
Description
I
2
C serial clock input terminal - clock signal for I
2
C serial data.
Power supply ground. All voltages are referenced to GND.
LED anode.
LED cathode. Connect to LDR pin when using internal driver circuit.
Proximity IR LED controlled current sink driver.
Interrupt — open drain (active low)
I
2
C serial data I/O terminal - serial data I/O for I
2
C.
Ordering Information
Figure TMD3782 – 5:
Ordering Information
Ordering Code
TMD37821
TMD37823
TMD37825
†
TMD37827
†
† Contact ams for availability.
Address
0x39
0x39
0x29
0x29
Interface
I
2
C V
bus
= V
DD
Interface
I
2
C bus = 1.8V Interface
I
2
C V
bus
= V
DD
Interface
I
2
C bus = 1.8V Interface
Delivery Form
Module-8
Module-8
Module-8
Module-8
TMD3782 – 4
Datasheet - Mar. 2013 - V2
Absolute Maximum Ratings
Stresses beyond those listed under “Absolute Maximum
Ratings” may cause permanent damage to the device. These are
stress ratings only. Functional operation of the device at these
or any other conditions beyond those indicated under
“Operating Conditions” is not implied. Exposure to absolute
maximum rating conditions for extended periods may affect
device reliability.
Figure TMD3782 – 6:
Absolute Maximum Ratings
Parameter
Supply voltage, V
DD
Digital I/O Voltage (except LDR)
Max LEDA Voltage (Note 2)
Max LDR Voltage (Note 3)
Output terminal current (except LDR)
Storage temperature range, T
stg
ESD tolerance, human body model
Notes:
1. All voltages are with respect to GND.
2. Maximum 4.8V DC over 7 years lifetime
Min
Max
3.8
Units
V
V
V
V
mA
ºC
V
Comments
All voltages are with respect to GND
-0.5
3.8
4.8
4.4
-1
-40
20
85
2000
Maximum 5.0V spikes with up to 250s cumulative duration over 7 years lifetime
Maximum 5.5V spikes with up to 10s (=1000*10ms) cumulative duration over 7 years lifetime
3. Maximum voltage with LDR = off
Electrical Characteristics
All limits are guaranteed. The parameters with min and max
values are guaranteed with production tests or SQC (Statistical
Quality Control) methods.
Figure TMD3782 – 7:
Recommended Operating Conditions
Symbol
V
DD
T
A
Note:
Parameter
Supply voltage
Operating free-air temperature (Note 1)
Min
2.7
-30
Typ
3
Max
3.3
85
Units
V
ºC
1. While the device is operational across the temperature range, functionality will vary with temperature. Specifications are
stated only at 25°C unless otherwise noted.
Datasheet - Mar. 2013 - V2
TMD3782 – 5
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