PNI SEN-L - Willow Technologies

Updated August, 2006
PNI SEN-L
Leaded Magneto-Inductive Sensor
General Description
Features
PNI Corporation’s Magneto-Inductive (MI)
sensors are based on patented technology that
delivers breakthrough, cost-effective magnetic
field sensing performance. These sensors change
inductance by 100% over their field measurement range. This variable inductance
property is used in a patented temperature and
noise stabilized oscillator/counter circuit to
detect field variations. The PNI ASIC is the
recommended implementation of this patented
circuit, and can be used with the Sen-L to
construct a magnetometer with up to three axes.
Advantages include low voltage and power,
small size leaded package, large signal noise
immunity under all conditions, and a large
dynamic
range.
Resolution
and
field
measurement range are software configurable
for a variety of applications. The measurement is
very stable over temperature and inherently free
from offset drift.
y Low power: draws < 500 µA at 3 VDC
y Small size: 14 x 4 mm (length x diameter)
y Large field measurement range: ±550 µT
(±5.5 Gauss)
y High resolution field measurement: 0.0055
µT (0.000055 Gauss)
y Few external components: PNI ASIC with
two resistors per sensor.
y Leaded component for through hole
mounting
These advantages have made PNI Corporation’s
MI sensors the choice for a wide variety of
applications.
Applications
y Handheld battery-powered devices with
built-in compass feature.
y High performance magnetic field sensing.
y High performance solid state navigation
equipment for automotive, marine, and
Aeronautic applications.
y Direction finding features for any device
where bearing or attitude indicators have
value.
y Magnetic object proximity sensing.
Ordering Information
Part #
MOQ
Package
RoHS Compliant
10165P
>1000
Each
Yes
10165
1000
Bag
Yes
Table 1
PNI Corporation 133 Aviation Blvd., suite 101, Santa Rosa, CA 95403-1084 USA
Phone: (707) 566-2260, Fax: (707) 566-2261, Web: www.pnicorp.com
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PNI SEN-L
Specifications
SPECIFICATIONS
CAUTION:
Stresses beyond those listed under Table 1 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 in the operational sections of the specifications is not
implied. Exposure to absolute maximum rating conditions for extended periods may
affect device reliability.
Table 2: Absolute Maximum Ratings
Symbol
Parameter
Maximum
VCOIL
Voltage across coil
2.5 VDC
VB
Coil breakdown voltage
200 VDC
IIN
Input pin current
20 mA at 25 ºC
TSTRG
Storage temperature
-55 ºC to 130 ºC
Table 3: Sensor Characteristics
Parameter
Minimum
a
DC resistance at 25 ºC
DC resistance versus temperature
Inductance
Q factor
b
c
Maximum
Typical
0.5%/ºC
0.4%/ºC
1.75 mH
5.25 mH
0.1
0.2
Operating Temperature
-30 ºC
80 ºC
Storage Temperature
-55 ºC
130 ºC
a.
b.
c.
Determined with a DC source
No DC bias, 100 kHz at 1 Vp-p, orthogonal to Earth’s magnetic field
Measured with an LCR meter
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PNI SEN-L
Specifications
Table 4: Sensor Characteristics with PNI ASIC
Parameter
Minimum
Current
(Measured at ASIC Vcc)
3 VDC, Rb = 100 Ÿ
5 VDC, Rb = 150Ÿ
Maximum
0.5 mA RMS
0.5 mA RMS
Typical
0.35 mA RMS
0.35 mA RMS
a
Field measurement range
3 VDC, Rb = 100 Ÿ
5 VDC, Rb = 150Ÿ
–550 µT
–550 µT
550 µT
550 µT
b
Gain
3 VDC, Rb = 100 Ÿ
5 VDC, Rb = 150 Ÿ
45 - 54 count/µT
29 - 37 count/µT
Linearity
(error from best fit straight line at ±100 µT)
1%
Resolution
1/gain µT
Frequency
3VDC, RB = 100 Ÿ
(Within free Earth’s magnetic field.)
Operating Temperature
(when used with PNI ASIC)
50 kHz
90 kHz
-20 ºC
70 ºC
a.
b.
Field measurement range is defined as the monotonic region of the output characteristic curve.
Gain is defined defined as the change in the number of counts from the ASIC, when the period select is set to 512, per
change in the magnetic field in µT. For situations requiring higher gain and less field measurement range, the gain and
resolution can be increased by a factor of 2 by setting the ASIC period select to 1024. When setting higher period selects,
be aware that the ASIC counter can overflow if the field is strong enough to drive the count beyond a signed 16-bit integer.
Period select set to 1024 is the highest setting where it is impossible to overflow the counter
For more information, see “PNI ASIC, 3-Axis Magneto-Inductive Sensor Driver and Controller with SPI Serial Interface” datasheet
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PNI SEN-L
Typical Operating Chracterisitics
Typical Operating Characteristics: SEN-L
(3 VDC; Rb = 100 Figure 1: Temperature Characteristics
Figure 2: Linearity vs. Temperature
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PNI SEN-L
Typical Operating Characteristics
Figure 3: Linearity vs. Temperature, normalized to Room Temperature (RMT)
Output Counts is defined as the Period Select (PS) setting for the PNI ASIC. For more information, see “PNI
ASIC, 3-Axis Magneto-Inductive Sensor Driver and Controller with SPI Serial Interface” datasheet.
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PNI SEN-L
Recommended Circuit Block Diagram
Recommended Circuit Block Diagram
Figure 4: Block Diagram
Rb is dependent on the supply voltage:
5 VDC: Rb = 150
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PNI SEN-L
Package Information
Package Information
Figure 5: Outline Dimensions
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PNI SEN-L
Sensor Lead Bending Instructions
Sensor Lead Bending Instructions
Tools Required:
y Needle Nose Pliers
y Ohm Meter
Procedure:
1. With the needle nose pliers, grip the sensor lead, next to the body of the sensor so that the pliers cover
a minimum of 2m of the lead. The actual length is to be determined by the application, but will never
be less than 2 mm. Refer to Figure 6.
2. Using your fingers, slowly bend the lead to 90º from the sensor while maintaining a hold on the lead
with the pliers.
3. Repeat Step 1 and Step 2 on the other lead, being careful to keep the second lead parallel to the first.
4. After both leads have been bent take a resistance reading of the sensor. If the reading is between
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Figure 6: Sensor Lead Bending
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