S i 11 02
O
PTICAL
P
ROXIMITY
D
ETECTOR
Features
Pin Assignments
High-performance proximity
detector with a sensing range of up
to 50 cm
Single-pulse sensing mode for low
system power
Adjustable detection threshold and
strobe frequency
Proximity (PRX) status latch
enables controlling devices to
avoid missing a detection
High EMI immunity without
shielded packaging
2 to 5.25 V power supply
Operating temperature range:
–40 to +85 °C
Typical 10 µA current consumption
and ultra-low power of 1 mA typical
Current driven (400 mA) or
saturated LED driver output
Small outline: 3x3 mm (ODFN)
Si1102
ODFN
PRX
TXGD
TXO
DNC
1
2
3
4
8
7
6
5
VSS
FR
SREN
VDD
Applications
Proximity sensing
Photo-interrupter
Occupancy sensing
Touchless switch
Object detection
Handsets
Intrusion/tamper detection
U.S. Patent 5,864,591
U.S. Patent 6,198,118
U.S. Patent 7,486,386
Other patents pending
Description
The Si1102 is a high-performance (0–50 cm) active proximity detector.
Because it operates on an absolute reflectance threshold principle, it avoids
the ambiguity of motion-based proximity systems.
The Si1102 consists of a patented, high-EMI immunity, differential photodiode
and a signal-processing IC with LED driver and high-gain optical receiver.
Proximity detection is based on measurements of reflected light from a
strobed, optically-isolated LED. The standard package for the Si1102 is an 8-
pin ODFN.
Functional Block Diagram
Reflectance-Based Proximity Detection
Hi-Lo
Threshold
Output
PRX
Infrared
emitter
Product
Case
FR
Signal
processing
SREN
IR
Oscillator
Shutdown
control
VDD
LED
Drive
TXO
VSS
Rev. 1.0 11/10
Copyright © 2010 by Silicon Laboratories
Si1102
Si1102
T
ABLE
Section
OF
C
ONTENTS
Page
1. Electrical Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4
2. Typical Application Schematic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6
3. Application Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
3.1. Theory of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
3.2. Choice of LED and LED Current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8
3.3. Power-Supply Transients . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8
3.4. Mechanical and Optical Implementation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8
3.5. Typical Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
4. Pin Descriptions—Si1102 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
5. Ordering Guide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
6. Photodiode Center . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
7. Package Outline (8-Pin ODFN) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14
Document Change List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15
Contact Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16
Rev. 1.0
3
Si1102
1. Electrical Specifications
Table 1. Absolute Maximum Ratings
Parameter
Conditions
Min
Typ
Max
Units
Supply Voltage
Operating Temperature
Storage Temperature
Voltage on TXO with respect to
GND
Voltage on all other Pins with
respect to GND
Maximum total current through
TXO (TXO Active)
Maximum Total Current through
TXGD and VSS
Maximum Total Current through
all other Pins
ESD Rating
Human body model
–0.3
–55
–65
–0.3
–0.3
—
—
—
—
—
—
—
—
—
—
—
—
—
5.5
85
85
5.5
VDD + 0.3
500
600
100
2
V
°C
°C
V
V
mA
mA
mA
kV
Table 2. Recommended Operating Conditions
Parameter
Symbol
Conditions/Notes
Min
Typ
Max
Units
Supply Voltage
Operating Temperature
SREN High Threshold
SREN Low Threshold
Active TXO Voltage
1
Peak-to-Peak Power Supply
Noise Rejection
DC Ambient light
LED Emission Wavelength
2
V
DD
–40 to +85 °C, V
DD
to VSS
2.2
–40
3.3
25
—
—
—
—
5.25
85
—
0.6
1.0
50
V
°C
V
V
V
mVPP
on V
DD
klux
nm
VIH
VIL
VDD – 0.6
—
—
V
DD
= 3.3 V, 1 kHz–10 MHz no
spurious PRX or less than 20%
reduction in range
—
Edc
V
DD
= 3.3 V
—
600
1
850
100
950
Notes:
1.
Minimum R1 resistance should be calculated based on LED forward voltage, maximum LED current, LED voltage rail
used, and maximum active TXO voltage.
2.
When using LEDs near the min and max wavelength limits, higher radiant intensities may be needed to achieve the
system's proximity sensing performance goals.
4
Rev. 1.0
Si1102
Table 3. Electrical Characteristics
Parameter
Symbol
Conditions/Notes
Min
Typ
Max
Units
PRX Logic High Level
PRX Logic Low Level
I
DD
Shutdown
I
DD
Average Current
I
DD
Average Current
I
DD
Current during Transmit,
Saturated Driver
I
DD
Current during Transmit,
Not Saturated
Sample Strobe Rate
1
Sample Strobe Rate
1
Sample Strobe Rate
1
Min. Detectable
Reflectance Input
SREN Low to TXO Active
TXO Leakage Current
TXO Current
2
TXO Saturation Voltage
VOH
VOL
I
DD
V
DD
= 3.3 V, Iprx = 4 mA
V
DD
= 3.3 V, Iprx = –4 mA
SREN = V
DD
, FR = 0,
V
DD
= 3.3 V
SREN = 0 V, V
DD
= 3.3 V, FR = 0
SREN = 0 V, V
DD
= 3.3 V,
FR = open
V
DD
= 3.3 V, LED I = 100 mA
V
DD
= 3.3 V, LED I = 400 mA
VDD – 0.6
—
—
30
—
—
5
100
—
—
—
200
—
100
—
—
—
0.1
120
5
8
14
250
7
2
1
500
0.01
380
0.5
—
0.6
1.0
200
20
—
30
600
30
8
—
1000
1
600
0.7
V
V
µA
µA
µA
mA
mA
Hz
Hz
Hz
µW/
cm
2
µs
µA
mA
V
FR
FR
FR
Emin
Tden
Itxo_sd
Itxo
1V
Vsat
V
DD
= 3.3 V, R2 = 0
V
DD
= 3.3 V, R2 = 100 k
V
DD
= 3.3 V, R2 = (open)
V
DD
= 3.3 V, 850 nm source
V
DD
= 3.3 V
V
DD
= 3.3 V, no strobe
V
TXO
= 1 V, V
DD
= 3.3 V
I
TXO =
I
TXO1V
x 80%
Notes:
1.
Max column also applies to VDD > 3.6 V. See Figure 6.
2.
When operating at VDD = 2.0 V, the typical TXO current is 250 mA.
Rev. 1.0
5
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