Si1141/42/4 3
P
R O X I M I T Y
/ A
M B I E N T
L
I G H T
S
E N S O R
I C
W I T H
I
2
C I
N T E R F A C E
Features
Integrated infrared proximity detector
Proximity detection adjustable from
under 1 cm up to 200 cm
Three independent LED drivers
15 current settings from 5.6 mA to
360 mA for each LED driver
25.6 μs LED driver pulse width
50 cm proximity range with single
pulse (<3 klx)
15 cm proximity range with single
pulse (>3 klx)
Operates at up to 128 klx (direct
sunlight)
High reflectance sensitivity
< 1 μW/cm
2
High EMI immunity without shielded
packaging
Integrated ambient light sensor
100 mlx resolution possible,
allowing operation under dark glass
1 to 128 klx dynamic range possible
across two ADC range settings
lux measurements with IR
correction algorithm
Industry's lowest power consumption
1.71 to 3.6 V supply voltage
9 μA average current (LED pulsed
25.6 μs every 800 ms at 180 mA
plus 3 μA Si114x supply)
< 500 nA standby current
25.6 μs LED “on” time keeps total
power consumption duty cycle low
without compromising performance
or noise immunity
Internal and external wake support
Built-in voltage supply monitor and
power-on reset controller
Serial communications
Up to 3.4 Mbps data rate
Slave mode hardware address
decoding (0x5A)
Small-outline 10-lead 2x2 mm QFN
Temperature Range
–40 to +85 °C
Accurate
Pin Assignments
Applications
Handsets
Heart rate monitoring
Pulse oximetry
Wearables
Audio products
Security panels
Tamper detection circuits
Dispensers
Valve controls
Smoke detectors
Touchless switches
Touchless sliders
Occupancy sensors
Consumer electronics
Industrial automation
Display backlighting control
Photo-interrupters
Description
The Si1141/42/43 is a low-power, reflectance-based, infrared proximity and ambient
light sensor with I2C digital interface and programmable-event interrupt output. This
touchless sensor IC includes an analog-to-digital converter, integrated high-
sensitivity visible and infrared photodiodes, digital signal processor, and one, two, or
three integrated infrared LED drivers with fifteen selectable drive levels. The Si1141/
42/43 offers excellent performance under a wide dynamic range and a variety of light
sources including direct sunlight. The Si1141/42/43 can also work under dark glass
covers. The photodiode response and associated digital conversion circuitry provide
excellent immunity to artificial light flicker noise and natural light flutter noise. With
two or more LEDs, the Si1142/43 is capable of supporting multiple-axis proximity
motion detection. The Si1141/42/43 devices are provided in a 10-lead 2x2 mm QFN
package and are capable of operation from 1.71 to 3.6 V over the –40 to +85 °C
temperature range.
Rev. 1.42 3/21
Copyright © 2021 by Silicon Laboratories
Si1141/42/43
Si1141/ 42/43
Functional Block Diagram
Figure 1. Si1141 Basic Application
Figure 2. Si1143 Application with Three LEDs and Separate LED Power Supply
Note:
For more application examples, refer to “AN498: Si114x Designer’s Guide”.
2
Rev. 1.42
Si114 1/4 2/43
T
A B L E O F
C
O N T E N T S
1. Electrical Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4
1.1. Performance Tables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4
1.2. Typical Performance Graphs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10
2. Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12
2.1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12
2.2. Proximity Sensing (PS) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12
2.3. Ambient Light . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13
2.4. Host Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14
3. Operational Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17
3.1. Off Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17
3.2. Initialization Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17
3.3. Standby Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17
3.4. Forced Conversion Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17
3.5. Autonomous Operation Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18
3.6. ALWAYS_ACTIVE Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18
3.7. Avoiding an Unexpected Reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18
4. Programming Guide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20
4.1. Command and Response Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20
4.2. Command Protocol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21
4.3. Command Write Timing Limitations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23
4.4. Resource Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .24
4.5. Signal Path Software Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .29
4.6. I2C Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .30
4.7. Parameter RAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .54
5. Pin Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .69
6. Ordering Guide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .70
7. Package Outline: 10-Pin QFN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .71
8. Suggested PCB Land Pattern . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .73
Document Change List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .77
Rev. 1.42
3
Si1141/ 42/43
1. Electrical Specifications
1.1. Performance Tables
Table 1. Recommended Operating Conditions
Parameter
V
DD
Supply Voltage
V
DD
OFF Supply Voltage
V
DD
Supply Ripple Voltage
Operating Temperature
SCL, SDA, Input High Logic
Voltage
SCL, SDA Input Low Logic
Voltage
PS Operation under
Direct Sunlight
IrLED Emission Wavelength
IrLED Supply Voltage
IrLED Supply Ripple Voltage
T
I
2
C
VIH
I
2
C
VIL
Edc
l
VLED
IrLED V
F
= 1.0 V nominal
Applies if IrLEDs use
separate supply rail
0–30 kHz
30 kHz–100 MHz
V
DD
above 1.71 V
Start-up
Symbol
V
DD
V
DD_OFF
OFF mode
V
DD
= 3.3 V
1 kHz–10 MHz
Test Condition
Min
1.71
–0.3
—
–40
V
DD
x0.7
0
—
750
V
DD
—
25
—
—
—
850
—
Typ
—
Max
3.6
1.0
50
85
V
DD
V
DD
x0.3
128
950
4.3
Unit
V
V
mVpp
°C
V
V
klx
nm
V
—
—
25
V
DD
x0.77
—
—
—
—
250
100
—
—
mVpp
mVpp
ms
V
Start-Up Time
LED3 Voltage
Table 2. Performance Characteristics
1
Parameter
I
DD
OFF Mode
I
DD
Standby Mode
Symbol
I
off
I
sb
Test Condition
V
DD
< V
DD_OFF
(leakage from SCL,
SDA, and INT not included)
No ALS / PS Conversions
No I
2
C Activity
V
DD
= 1.8 V
Min
—
—
Typ
240
150
Max
1000
500
Unit
nA
nA
Notes:
1.
Unless specifically stated in "Conditions", electrical data assumes ambient light levels < 1 klx.
2.
Proximity-detection performance may be degraded, especially when there is high optical crosstalk, if the LED supply
and voltage drop allow the driver to saturate and current regulation is lost.
3.
Guaranteed by design and characterization.
4.
Represents the time during which the device is drawing a current equal to I
active
for power estimation purposes.
Assumes default settings.
4
Rev. 1.42
Si114 1/4 2/43
Table 2. Performance Characteristics
1
(Continued)
Parameter
I
DD
Standby Mode
Symbol
I
sb
Test Condition
No ALS / PS Conversions
No I
2
C Activity
V
DD
=3.3 V
Without LED influence, V
DD
= 3.3 V
V
DD
= 3.3 V
Min
—
Typ
1.4
Max
—
Unit
μA
I
DD
Actively Measuring
Peak IDD while LED1,
LED2, or LED3 is
Actively Driven
LED Driver Saturation
Voltage
2,3
I
active
—
—
4.3
8
5.5
—
mA
mA
Vdd = 1.71 to 3.6 V
PS_LEDn = 0001
PS_LEDn = 0010
PS_LEDn = 0011
PS_LEDn = 0100
PS_LEDn = 0101
PS_LEDn = 0110
PS_LEDn = 0111
PS_LEDn = 1000
PS_LEDn = 1010
PS_LEDn = 1010
PS_LEDn = 1011
PS_LEDn = 1100
PS_LEDn = 1101
PS_LEDn = 1110
PS_LEDn = 1111
t
PS
V
DD
= 3.3 V
mV
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
–1
50
60
70
80
115
150
185
220
255
290
315
340
360
385
410
25.6
—
70
105
105
105
450
450
450
450
450
450
600
600
600
600
600
30
1
μs
μA
LED1, LED2, LED3
Pulse Width
LED1, LED2, LED3,
INT, SCL, SDA
Leakage Current
Notes:
1.
Unless specifically stated in "Conditions", electrical data assumes ambient light levels < 1 klx.
2.
Proximity-detection performance may be degraded, especially when there is high optical crosstalk, if the LED supply
and voltage drop allow the driver to saturate and current regulation is lost.
3.
Guaranteed by design and characterization.
4.
Represents the time during which the device is drawing a current equal to I
active
for power estimation purposes.
Assumes default settings.
Rev. 1.42
5
