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Datasheet SFM3000
Low Pressure Drop Digital Flow Meter
Low pressure drop
Flow range: +/- 200 slm (bidirectional)
Accuracy 1.5% m.v. (typical)
Very fast update time (0.5ms)
Fully calibrated & temperature compensated
Zero offset, no drift
Product Summary
The SFM3000 sensor is Sensirion’s digital flow meter
designed for high-volume applications. It measures the flow
rate of air, oxygen and other non-aggressive gases with
superb accuracy. A special design of the flow channel
results in the very low pressure drop through the flow body
of the sensor making it extremely suitable for very
demanding applications, such as medical ventilation and
respiratory applications.
The SFM3000 operates from a 5 Volt supply voltage and
features a digital 2-wire I2C interface. The measurement
results are internally linearized and temperature
compensated.
The outstanding performance of this sensor is based on
Sensirion’s patented CMOSens® sensor technology,
which combines the sensor element, signal processing
and digital calibration on a single microchip. The flow rate
of the gas is measured by a thermal sensor element which
assures very fast signal processing time and bi-
directional measurement with best-in-class accuracy.
The well-proven CMOS technology is perfectly suited for
high-quality mass production and is the ideal choice for
demanding and cost-sensitive OEM applications.
Applications
Medical
Process automation
Burner control
Fuel cell control
Spectroscopy
Environment monitoring
Laboratory
OEM options
A variety of custom options can be implemented for high-
volume OEM applications (custom flow rates, calibration
for other gases, different body form factor etc.). Contact
Sensirion for more information.
Sensor chip
The SFM3000 flow meter features a fifth-generation silicon
sensor chip SF05. In addition to a thermal mass flow
sensor element, the chip contains an amplifier, A/D
converter, EEPROM memory, digital signal processing
circuitry, and interface. Due to seamless integration of
signal acquisition and processing on the single silicon die
significant performance and cost benefits are achieved.
Connection diagram
Micro
controller
(master)
SFM3000
(slave)
VDD
GND
SDA
SCL
5V
SFM3000 with bidirectional digital communication (I2C bus)
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1. Sensor performance
1.1 Physical specifications
1
Parameter
Condition
Value
Unit
Flow Ranges
Air/N2/O2
-200 … +200 2
slm 3
Update Time
14 bit
0.5
ms
Max.
Typ.
Accuracy 4,5,6,7
span
offset
± 2.5
± 0.1
± 1.5
± 0.05
% m.v. 8
slm
Repeatability 4,7
span
offset
± 1
± 0.05
± 0.5
± 0.02
% m.v.
slm
Noise Level 4,7
span
offset
± 1
± 0.1
± 0.5
± 0.05
% m.v.
slm
Accuracy Shift Due to
Temperature Variation 9
span
offset
± 0.75
± 0.0
± 0.25
± 0.0
% m.v./10°C
slm
Position sensitivity 10
non-horizontal position
< 0.05
slm
Pressure Drop
@60slm
@200slm
< 100 / < 0.4
< 600 / < 2.4
Pa / inH2O
1.2 Media compatibility and materials
Parameter
Value
Calibration 11
Air, N2, O2
Media Compatibility
Air (non-condensing), N2, O2, non- aggressive gases
Wetted Materials
PPE+PS blend (medical grade: biocompatible; ISO 10993 or USP Class VI), Si,
Si3N4, SiOx, Gold, Epoxy, Polyurethane, stainless steel (annealed)
RoHS, REACH
RoHS and REACH compliant
Sensor Weight with Cap
< 18 gram
1.3 Temperature and pressure conditions
Parameter
Condition
Value
Unit
Calibrated Temperature Range11
T(environment) = T(gas)
-20 … +80
°C
Operating Temperature Range11
Non-condensing
-20 … +80
°C
Storage Temperature
Non-condensing
-20 … +80
°C
Operating Pressure Range
absolute
0.7 – 1.3
bar
Operating Overpressure
gauge
± 0.2
bar
Burst Overpressure
gauge
> 1
bar
1
Unless otherwise noted, all sensor specifications are valid at 25°C with Vdd = 5V and absolute pressure = 966 mbar.
2
Other calibration ranges are available for large volume projects
3
In standard liter per minute at 20°C and 1013 mbar
4
With ideal inlet and outlet conditions, at VDD = 5V, 25°C, absolute pressure = 966 mbar
5
Including offset, non-linearity, hysteresis
6
Sensor position horizontal (see Section 4.1)
7
Span or offset value, whichever is larger
8
In % of measured value (m.v.) = of rate = of reading
9
Shift due to temperature variation compared to calibration temperature
10
See Section 4.1
11
Contact Sensirion for information about other gases, wider calibrated and operating temperature ranges
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2. Electrical specifications
2.1 Electrical characteristics
Electrical properties
Condition
Value
Unit
Interface
I2C
Default Sensor Address
64 (0x40)
Soft Reset Time
80
ms
Start-up Time 12
Max.
100
ms
Supply Voltage (VDD)
5V +/-5%
V
I2C Communication Level
High
Low
Min.
Max.
V
2.5
GND
VDD
1.1
I2C Bus clock frequency
Max.
400
kHz
Power Consumption
< 50
mW
Electrical Connector
2 mm pitch, 4 pins in a row
Output signal resolution
1413
bit
Scale Factor Flow
Air, N2
O2
140
142.8
1/slm
Offset Flow
32’000
12
After 4.75V is reached
13
16 bit with two least significant bits always zero
2.2 Pin layout and mechanical concept of the
electrical connection
The SFM3000 is designed for both connector attachment
and through-hole technology hand-soldering to a PCB.
2.2.1 Connector attachment
The SFM3000 sensor’s 4-pin 2 mm pitch electrical
connector is compatible with Molex DuraClik™ socket
(Molex product number: 502351-0400). For this type of
connection please order the SFM3000 with a cap
(according to the ordering information in Chapter 5).
Diverse 4-core flat ribbon cables with crimp fittings can be
used for electrical connection.
2.2.2 PCB soldering
Standard selective soldering systems may be used for
soldering SFM3000 sensors. Reflow soldering is not
feasible and may damage the sensor. The sensor ports
must be protected from solder splash and flux during
soldering. The characteristics of selective soldering
machines vary, so any soldering setup must be tested
before production use.
2.3 Conversion to physical values
In order to obtain the measured flow in [slm], the
measured value needs to be converted using the following
formula:
𝑓𝑙𝑜𝑤 [slm] = 𝑚𝑒𝑎𝑠𝑢𝑟𝑒𝑑 𝑣𝑎𝑙𝑢𝑒 − 𝑜𝑓𝑓𝑠𝑒𝑡 𝑓𝑙𝑜𝑤
𝑠𝑐𝑎𝑙𝑒 𝑓𝑎𝑐𝑡𝑜𝑟 𝑓𝑙𝑜𝑤
Please note that the first measurement performed directly
after chip initialization is not valid.
Positive flow direction
(as marked on the sensor body)
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3. Mechanical specifications
All dimensions are in millimeters (mm).
3.1 SFM3000 without cover (PCB mount)
3.2 Footprint
Please refer to the mask given below for reliable PCB
attachment using the dedicated snap-in feet.
Consider using the screw holes of the SFM3000 for a
sturdy integration of the sensor.
3.3 SFM3000 with cover
If used with cover, sensor height is 34.4 mm instead of 33
mm. All the other dimensions are the same
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3.4 Mechanical fitting
Fittings of the SFM3000 sensor correspond to the
international standard ISO5356-1:2004. Details about this
type of connection can be found in the description of the
standard. To minimize the risk of connectors being
accidentally disconnected, latching connectors can be
suggested.
It is also possible to insert O-rings in the grooves and
attach tubes with an inner diameter of 23 mm to the
SFM3000.
Cross section of recommended O-ring
4. Instructions for use
4.1 Calibration orientation
The sensors are calibrated horizontally as depicted in the
following graph:
4.2 Inlet flow conditions
In order to provide good flow conditions, the inner
diameter of the connecting tube has to be approximately
the same as the inner diameter of the SFM3000 main flow
channel. The inlet tube has to be straight and at least 10
cm in length. The SFM3000 is equipped with meshes on
the in- and outlets of the flow channel to reduce
turbulences and thus improve the stability.
Please refer to the application note “Inlet conditions for the
SFM3000 Mass flow meters” for more information.
4.3 Temperature compensation
The SFM3000 sensor features digital temperature
compensation. The temperature is measured on the
CMOSens® chip by an on-chip temperature sensor. This
data is fed to a compensation circuit that is also integrated
on the CMOSens® sensor chip. Thus, no external
temperature compensation is necessary.
4.4 Sensor handling
The SFM3000 sensor is designed to be robust and shock
resistant. Nevertheless, the accuracy of the high-precision
SFM3000 can be degraded by rough handling. Sensirion
does not guarantee proper operation in case of improper
handling. Note: avoid applying any mechanical stress to
the solder joints of the sensor during or as a result of PCB
assembly.
4.5 ESD
The electronics of the SFM3000 sensor consist of a single
automotive qualified chip. It complies with the following
ESD norms:
- AEC Q 100 002 (4kV HBM)
- AEC Q 100 003 (200V MM)
Although the sensor complies with these norms, it does
not mean the sensor is immune against ESD.
The sensor is shipped in an antistatic tray to prevent
electrostatic discharge. To avoid damage to the sensor,
ground yourself using a grounding strap or by touching a
grounded object before touching the sensor. Furthermore,
store the parts in an antistatic package when not in use.
4.6 I2C Interface and communication
Due to I2C interface restrictions, the cable length from the
sensor to the microprocessor is recommended to be as
short as possible and certainly not above 30 cm. For wires
longer than 10 cm it is mandatory to shield the SDA and
SCL.
In case data is read from the sensor, the first data byte of
the transaction must always be acknowledged by the
master.
It must be possible to reset the sensor through a hard
reset, i.e. powering off and on the sensor, in case the
sensor freezes.
I2C Communication details are given in the application
note “I2C Functional Description for SFM3000”.
d1 = 19mm
d2 = 2mm
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5. Ordering information
Use the part names and product numbers shown in the
table below when ordering SFM3000 sensors. For the
latest product information and local distributors, visit
www.sensirion.com.
Part name
Cap
Product Number
1-100xxx-xx
SFM3000-200-C
With
932-02
SFM3000-200
Without
934-02
Packaging units: 20 items/tray.
Every sensor is traceable by a unique Serial Number.
Revision history
Date
Author
Version
Changes
July 2013
ANB
1
First release
February 2014
ANB
2
Updated material to Noryl
December 2015
ANB
2.1
Updated temperature ranges
Clarified max/min pressures
Updated product picture.
July 2016
ANB
2.2
Change of potting material.
Product number post-fix updated
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Important Notices
Warning, personal injury
Do not use this product as safety or emergency stop devices or in
any other application where failure of the product could result in
personal injury (including death). Do not use this product for
applications other than its intended and authorized use. Before
installing, handling, using or servicing this product, please
consult the datasheet and application notes. Failure to comply
with these instructions could result in death or serious injury.
If the Buyer shall purchase or use SENSIRION products for any
unintended or unauthorized application, Buyer shall defend, indemnify
and hold harmless SENSIRION and its officers, employees,
subsidiaries, affiliates and distributors against all claims, costs,
damages and expenses, and reasonable attorney fees arising out of,
directly or indirectly, any claim of personal injury or death associated
with such unintended or unauthorized use, even if SENSIRION shall be
allegedly negligent with respect to the design or the manufacture of the
product.
ESD Precautions
The inherent design of this component causes it to be sensitive to
electrostatic discharge (ESD). To prevent ESD-induced damage and/or
degradation, take customary and statutory ESD precautions when
handling this product.
See application note “Handling Instructions” for more information.
Warranty
SENSIRION warrants solely to the original purchaser of this product for
a period of 12 months (one year) from the date of delivery that this
product shall be of the quality, material and workmanship defined in
SENSIRION’s published specifications of the product. Within such
period, if proven to be defective, SENSIRION shall repair and/or
replace this product, in SENSIRION’s discretion, free of charge to the
Buyer, provided that:
notice in writing describing the defects shall be given to
SENSIRION within fourteen (14) days after their appearance;
such defects shall be found, to SENSIRION’s reasonable
satisfaction, to have arisen from SENSIRION’s faulty design,
material, or workmanship;
the defective product shall be returned to SENSIRION’s factory at
the Buyer’s expense; and
the warranty period for any repaired or replaced product shall be
limited to the unexpired portion of the original period.
This warranty does not apply to any equipment which has not been
installed and used within the specifications recommended by
SENSIRION for the intended and proper use of the equipment.
EXCEPT FOR THE WARRANTIES EXPRESSLY SET FORTH
HEREIN, SENSIRION MAKES NO WARRANTIES, EITHER EXPRESS
OR IMPLIED, WITH RESPECT TO THE PRODUCT. ANY AND ALL
WARRANTIES, INCLUDING WITHOUT LIMITATION, WARRANTIES
OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR
PURPOSE, ARE EXPRESSLY EXCLUDED AND DECLINED.
SENSIRION is only liable for defects of this product arising under the
conditions of operation provided for in the datasheet and proper use of
the goods. SENSIRION explicitly disclaims all warranties, express or
implied, for any period during which the goods are operated or stored
not in accordance with the technical specifications.
SENSIRION does not assume any liability arising out of any application
or use of any product or circuit and specifically disclaims any and all
liability, including without limitation consequential or incidental damages.
All operating parameters, including without limitation recommended
parameters, must be validated for each customer’s applications by
customer’s technical experts. Recommended parameters can and do
vary in different applications.
SENSIRION reserves the right, without further notice, (i) to change the
product specifications and/or the information in this document and (ii) to
improve reliability, functions and design of this product.
Copyright © 2016, SENSIRION.
CMOSens® is a trademark of Sensirion
All rights reserved
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