Human Interface Products Copyright © 2009 by Silicon Labora tories 5.18.09
IC2 IC1
IR VIS
MUX AMP CMP
BUF PRX
VDD
TXO
TXGDVSS
MD
SC
STX
VREG
RAMP
GEN
MODE
CTRL TX
Si1120
Proximity/Ambient Light Sensor with PWM Output
Description
The Si1120 is a low-power, reflectance-based
proximity and ambient light sensor with advanced
analog signal processing and analog PWM output. It
includes an integrated differential photodiode, signal
processor, and LED driver. Proximity sensing is
based on the measurement of reflected light from an
external, optically-isolated, strobed LED. A separate
visible light photodiode is used for ambient light
sensing.
The standard package for the Si1120 is an 8-pin
ODFN.
Features
-0–1/2 meter proximity range with single pulse
-7 precision optical measurement modes
-3 Proximity ranges
-3 dc ambient ranges
-1 calibration mode
-Low-noise ambient cancelling circuit allows maximum
sensitivity with 8–12 bit resolution
-Works in direct sunlight (100 klux)
-Minimum reflectance sensitivity <1 µW/cm2
-High EMI immunity without shielded packaging
-Power supply: 2.2–3.7 V
-Operating temperature range: –40 to +85 °C
-Typical 10 µA current consumption
-Programmable 400/50 mA LED constant current
driver output
-Allows independent LED supply voltage
-Small outline 3 x 3 mm (ODFN)
-U.S. Patents 5,864,591 and 6,198,118
(others pending)
Applications
-Handsets
-Touchless switches
-Occupancy sensors
-Consumer electronics
-Notebooks/PCs
-Industrial automation
-Display backlighting control
-Photo-interrupter
Human Interface Products Copyright © 2009 by Silicon Laboratories 5.18.09
Silicon Laboratories and Silicon Labs are trademarks of Silicon Laboratories Inc.
Other products or brandnames mentioned herein are trademarks or registered trademarks of their respective holders.
Si1120
Proximity/Ambient Light Sensor with PWM Output
Selected Electrical Specifications
(TA = –40 to +85 °C unless otherwise specified)
Parameter Conditions Min Typ Max Units
Supply Voltage –40 to +85 °C, VDD to VSS 2.2 3.3 3.7 V
Operating Temperature –40 —85 °C
PRX pulse width range VDD = 3.3 V 4 2000 µs
DC Ambient light (Edc) VDD = 3.3 V 100 klux
IDD Shutdown SC = VDD = 2.2 to 3.7 V 0.1 1.0 µA
IDD idle current SC = STX = 0 V, VDD = 3.3 V 120 µA
IDD current during trans-
mit, not saturated LED I = 50 mA, VDD = 3.3 V 3 µA
Min. Detectable
Reflectance Input VDD = 3.7 V 1 µW/cm2
Pin Assignments
PRX
TXGD
TXO
STX
VSS
MD
SC
VDD
1
2
3
4
8
7
6
5
Si1120
ODFN-8
8-Pin ODFN Package
Symbol Millimeters
Min Typ Max
A 0.55 0.65 0.75
b 0.25 0.30 0.35
D 3.00 BSC.
D2 1.40 1.50 1.60
e 0.65 BSC.
E 3.00 BSC.
E2 2.20 2.30 2.40
L 0.30 0.35 0.40
aaa 0.10
bbb 0.10
ccc 0.08
ddd 0.10
Product Family
Part Number Pkg LED
Drivers LED Drive Methods Range Measurement
Modes Resolution
Si1120-A-GM ODFN-8 1 Current Drive n
(400 mA), Saturated 50 cm 3 Proximity
3 DC Ambient
1 Calibration
8 to 12 bits
