Document Outline
- Top
- Features
- Product Description
- Applications
- Specifications
- Pin Configuration
- Package Outline
- Mounting Considerations
- Basic Device Operation
- Application Notes
- Ordering Information
HMC1023
SENSOR PRODUCTS
3-AXIS MAGNETIC SENSOR
Features
Ball Grid Array (BGA) Surface-Mount Package
Three Orthogonal Magneto-Resistive Sensors
Wide Field Range of 6 Gauss
1.0 mV/V/gauss Sensitivity
Minimum Detectable Field to 85 gauss
Patented On-Chip Set/Reset and Offset Straps
Product Description
The Honeywell HMC1023 is a high performance three-
axis magneto-resistive sensor design in a single
package. The advantages of the HMC1023 include
orthogonal three-axis sensing, small size and a 16-
contact BGA surface mount package.
Each of the magneto-resistive sensors are configured
as 4-element Wheatstone bridges to convert magnetic
fields to differential output voltages. Capable of sensing
fields down to 85 micro-gauss, these sensors offer a
compact, high sensitivity and highly reliable solution for
low field magnetic sensing.
APPLICATIONS
HMC1023 Circuit Diagram
Compassing
Navigation Systems
Attitude Reference
Traffic Detection
Medical Devices
Solid State Electronics Center www.magneticsensors.com (800) 323-8295 Page 1
HMC1023
SENSOR PRODUCTS
SPECIFICATIONS
Characteristics
Conditions*
Min
Typ
Max
Units
Bridge Elements
Supply
Vbridge referenced to GND
1.8
5.0
12
Volts
Resistance
Bridge current = 5mA, VCC to GND
250
350
450
ohms
Operating
Temperature
Ambient
-40
125
C
Storage
Temperature
Ambient, unbiased
-55
125
C
Humidity
Tested at 121C
100
%
Field Range
Full scale (FS) total applied field
-6
+6
gauss
Linearity Error
Best fit straight line
1 gauss
3 gauss
6 gauss
0.05
0.4
1.6
%FS
Hysteresis Error
3 sweeps across 3 gauss
0.08
%FS
Repeatability Error
3 sweeps across 3 gauss
0.08
%FS
Bridge Offset
Offset = (OUT+) (OUT-)
Field = 0 gauss after Set pulse, VCC = 5V
-10
2.5
+10
mV
Sensitivity
Set/Reset Current = 2.0A
0.8
1.0
1.2
mV/V/gauss
Noise Density
@ 1kHz, VCC=5V
48
nV/sqrt Hz
Resolution
50Hz Bandwidth, VCC=5V
85
gauss
Bandwidth
Magnetic signal (lower limit = DC)
5
MHz
Disturbing Field
Sensitivity starts to degrade.
Use S/R pulse to restore sensitivity.
20
gauss
Sensitivity
Tempco
T
A
= -40 to 125C, VCC=5V
T
A
= -40 to 125C, ICC=5mA
-2800
-3000
-600
-3200
ppm/C
Bridge Offset
Tempco
T
A
= -40 to 125C, No Set/Reset
T
A
= -40 to 125C, With Set/Reset
500
10
ppm/C
Bridge Ohmic
Tempco
VCC=5V, T
A
= -40 to 125C
2100
2500
2900
ppm/C
Cross-Axis Effect
Cross field = 1 gauss, Happlied = 1 gauss
+0.3
%FS
Max. Exposed
Field
No perming effect on zero reading
200
gauss
Sensitivity Ratio of
X,Y,Z Sensors
T
A
= -40 to 125C
1005
%
X,Y, Z sensor
Orthogonality
Sensitive direction in X, Y and Z sensors
1.0
degree
* Tested at 25C except stated otherwise.
Solid State Electronics Center www.magneticsensors.com (800) 323-8295 Page 2
HMC1023
SENSOR PRODUCTS
SPECIFICATIONS
Characteristics
Conditions*
Min
Typ
Max
Units
Set/Reset Strap
Resistance
Measured from S/R+ to S/R-
2.0
3.0
4.0
ohms
Current
0.1% duty cycle, or less,
2 sec current pulse
1.5
2.0
4.0
Amp
Resistance
Tempco
T
A
= -40 to 125C
3300
3700
4100
ppm/C
Offset Straps
Resistance
Measured from OFFSET+ to OFFSET-
40
50
60
ohms
Offset
Constant
DC Current
Field applied in sensitive direction
4.0
4.6
6.0
mA/gauss
Resistance
Tempco
T
A
= -40 to 125C
3500
3900
4300
ppm/C
* Tested at 25C except stated otherwise.
Pin Configuration
(Arrows indicate direction of applied field that generates a positive output voltage
after a SET pulse.)
Package Outline
Solid State Electronics Center www.magneticsensors.com (800) 323-8295 Page 3
HMC1023
SENSOR PRODUCTS
Mounting Considerations
When mounting the Honeywell HMC1023 on a circuit board, please consider the following advice for ball grid array
component attachment.
Ball Grid Array attachment/removal to printed circuit boards is precisely controlled thermal solder reflow process. To
prevent internal electrical damage and package cracking, do not use conventional soldering iron/solder station tools. If
you do not have experience and the reflow oven, please have a qualified BGA rework technician do the work for you.
The reflow profile show below is the recommended profile for HMC1023 package attachment.
Melting temperature for the HMC1023 balls is at 180C. The recommended rise and fall temperatures should be no
greater than 3C/sec to prevent mechnical stresses or "popcorning". Peak external temperature the part should be
exposed to is between 200 to 210C. When exposed a high temperature, such as the solder reflow process, the
internal connections in the package could sustain permanent damage, leaving open connections. 225C is the melting
point of solder inside the HMC1023 Ball Grid Array package. Do not expose the part to this level of temperature.
If using solder paste, we recommend Kester SN62 solder paste with water soluble flux R560. This has a melting point
around 180C. Kester recommends a pre-heating zone from ambient temperature to 180C for 2 to 4 minutes
maximum. The first part of this pre-heating zone ramps up from ambient to 150C in 90 seconds with a ramp rate of
less than 2.5 degrees C per second. The soak zone should last from 60 to 90 seconds (2 minutes maximum) and
ramp up in temperature from 150 to 180C at 0.5 to 0.6 C/ sec. The reflow zone should last for 30 to 90 seconds
maximum (40 to 60 seconds is ideal) and peak in temperature between 200 and 210C with a ramp of 1.3 to
1.6C/sec.
Solid State Electronics Center www.magneticsensors.com (800) 323-8295 Page 4
The reflow parameters can vary significantly and excellent reflow results can still be achieved. A thin layer of paste
flux or a 2 to 3 mil layer of solder paste applied to the mother-board prior to placing the HMC1023 is helpful. The
profile can be verified by placing a thermocouple between the HMC1023 and motherboard.
HMC1023
SENSOR PRODUCTS
Basic Device Operation
The Honeywell HMC1023 magneto-resistive sensor is composed of three Wheatstone bridge elements to measure
magnetic fields for both field strength and direction. With power applied to the bridges, the sensors elements convert
any incident magnetic field in each element's sensitive axis direction to a differential voltage output. In addition to the
bridge elements, these sensors have two types of on-chip magnetically coupled straps; the offset straps and the
set/reset strap. These straps are Honeywell patented features for incident field adjustment and magnetic domain
alignment; and eliminate the need for external coils positioned around the sensors.
The magnetoresistive sensors are made of a nickel-iron (Permalloy) thin-film deposited on a silicon wafer and
patterned as a resistive strip element. In the presence of a magnetic field, a change in the bridge resistive elements
causes a corresponding change in voltage across the bridge outputs.
These resistive elements are aligned together to have a common sensitive axis (indicated by arrows on the pinouts)
that will provide positive voltage change with magnetic fields increasing in the sensitive direction. Because the output
only is in proportion to the one-dimensional axis (the principle of anisotropy) and its magnitude, additional sensor
bridges placed at orthogonal directions permit accurate measurement of arbitrary field direction. The combination of
sensor bridges in this three orthogonal axis configuration permit applications such as compassing and magnetometry.
The individual sensor offset straps allow for several modes of operation when a direct current is driven through it.
These modes are: 1) Subtraction (bucking) of an unwanted external magnetic field, 2) null-ing of the bridge offset
voltage, 3) Closed loop field cancellation, and 4) Auto-calibration of bridge gain.
The set/reset strap can be pulsed with high currents for the following benefits: 1) Enable the sensor to perform high
sensitivity measurements, 2) Flip the polarity of the bridge output voltage, and 3) Periodically used to improve
linearity, lower cross-axis effects, and temperature effects.
Noise Characteristics
The noise density for the HMR1023 series is around 50nV/sqrt Hz at the 1 Hz corner, and drops below 10nV/sqrt Hz
at 20Hz and begins to fit the Johnson Noise value at around 5nV/sqrt Hz beyond 100Hz. The 10Hz noise voltage
averages around 0.58 micro-volts with a 0.16 micro-volts standard deviation. These values are provided with a 5-volt
supply.
Offset Strap
The offset strap is a spiral of metalization that couples in the sensor element's sensitive axis. In the HMC1023 design,
there is one strap per bridge with both ends brought out externally. Each offset strap measures nominally 50 ohms,
and requires about 4.6mA for each gauss of induced field. The straps will easily handle currents to buck or boost
fields through the 6 gauss linear measurement range, but designers should note the extreme thermal heating on the
sensor die when doing so.
With most applications, the offset strap is not utilized and can be ignored. Designers can leave one or both strap
connections (Off- and Off+) open circuited, or ground one connection node. Do not tie positive and negative strap
connections together of the same strap to avoid shorted turn magnetic circuits.
Set/Reset Strap
The set/reset strap is another spiral of metalization that couples to the sensor elements easy axis (perpendicular to
the sensitive axis on the sensor die). The HMC1023 set/reset strap circuit has three straps (one per sensor) paralleled
together for operation at low voltages. The set/reset strap connections have a nominal resistance of 3.0 ohms with a
minimum required peak current of 1.5A for reset or set pulses. With rare exception, the set/reset strap must be used
to periodically condition the magnetic domains of the magneto-resistive elements for best and reliable performance.
A set pulse is defined as a positive pulse current entering the S/R+ strap connection. The successful result would be
the magnetic domains aligned in a forward easy-axis direction so that the sensor bridge's polarity is a positive slope
with positive fields on the sensitive axis result in positive voltages across the bridge output connections.
Solid State Electronics Center www.magneticsensors.com (800) 323-8295 Page 5
HMC1023
SENSOR PRODUCTS
A reset pulse is defined as a negative pulse current entering the S/R+ strap connection. The successful result would
be the magnetic domains aligned in a reverse easy-axis direction so that sensor bridge's polarity is a negative slope
with positive fields on the sensitive axis result in negative voltages across the bridge output connections.
Typically a reset pulse is sent first, followed by a set pulse
a few milliseconds later. By shoving the magnetic domains
in completely opposite directions, any prior magnetic
disturbances are likely to be completely erased by the duet
of pulses. For simpler circuits with less critical
requirements for noise and accuracy, a single polarity
pulse circuit may be employed (all sets or all resets). With
these uni-polar pulses, several pulses together become
close in performance to a set/reset pulse circuit. Figure 1
shows a quick and dirty manual pulse circuit for uni-polar
application of pulses to the set/reset strap.
Rsr
3.0
Rsr
3.0
Iset
5 volts
Iset
5 volts
Figure 1
Set Pulse Circuit
Application Notes
Three Axis Compassing with Tilt Compensation
For full three-axis compassing, the circuit depicted in Figure 2 shows HMC1023 used for sensing the magnetic field
in three axes. A two-axis accelerometer with digital (PWM) outputs is also shown to provide pitch and roll (tilt)
sensing, to correct the three-axis magnetic sensors outputs into to the tilt-compensated two-axis heading. The
accelerometer can be substituted with a fluidic 2-axis tilt sensor if desired. For lower voltage operation with Lithium
battery supplies (2.5 to 3.6Vdc), the Set/Reset circuit should be upgraded from a single IRF7509 to the dual IRF7509
implementation (H-bridge) to permit a minimum 1.5-ampere pulse (500mA per set/reset strap resistance) to the
sensors.
Figure 7
Three Axis Compass
HMC1023
U1
Vcc
set/reset
.33uf
IRF7509
set/reset
Vcc/2
Vcc/2
5.00k
5.00k
500k
500k
5.00k
5.00k
500k
500k
LMV324
LMV324
1nf
1nf
U3
U4
3.3 to 5.0v
U2
Vcc
Vcc/2
5.00k
5.00k
500k
500k
LMV324
.1 f
+
-
C
with
Multiplexed
A/D Conv.
AN0
AN1
AN2
AN3
Vcc/2
U6
U5
xout
yout
Two-axis
accelerometer
Vcc
Vcc
DO0
DI0
DI1
HMC1023
U1
Vcc
set/reset
.33uf
IRF7509
set/reset
Vcc/2
Vcc/2
5.00k
5.00k
500k
500k
5.00k
5.00k
500k
500k
LMV324
LMV324
1nf
1nf
U3
U4
3.3 to 5.0v
U2
Vcc
Vcc/2
5.00k
5.00k
500k
500k
LMV324
.1 f
+
-
C
with
Multiplexed
A/D Conv.
AN0
AN1
AN2
AN3
Vcc/2
U6
U5
xout
yout
Two-axis
accelerometer
Vcc
Vcc
DO0
DI0
DI1
Solid State Electronics Center www.magneticsensors.com (800) 323-8295 Page 6
HMC1023
SENSOR PRODUCTS
Duty Cycling for Lower Energy Consumption
For battery powered and other applications needing limited energy consumption, the sensor bridge and support
electronics can be switched "off" between magnetic field measurements. The HMC1023 sensors are very low
capacitance (Bandwidth > 5MHz) sensor bridges and can stabilize quickly, typically before the support electronics
can. Other energy saving ideas would be to minimize the quantity of set/reset pulses which saves energy over the
battery life. Figure 3 shows a simple supply switching circuit that can be microprocessor controlled to duty cycle
(toggle) the electronics in moderate current (<25mA) applications.
MMBT2907ALT1
C
To Sensor Circuits
toggle
10k
+
-
10 f
0.01 f
Vcc
Vcc
Gnd
*MMBD7001LT1
* Used when Vcc = 5.0 volts, jumper
when using Vcc = 3.3 volts or less.
MMBT2907ALT1
C
To Sensor Circuits
toggle
10k
+
-
10 f
0.01 f
Vcc
Vcc
Gnd
*MMBD7001LT1
* Used when Vcc = 5.0 volts, jumper
when using Vcc = 3.3 volts or less.
Off
On
Off
On
Figure 3
Duty Cycling
ORDERING INFORMATION
Part Number
Package Style
HMC1023
Three Axis Magnetic Sensor
HMC1023PCB
Three Axis Magnetic Sensor 16-Pin DIP Demo
The application circuits herein constitute typical usage and interface of Honeywell product. Honeywell does not
warrant or assume liability for customer-designed circuits derived from this description or depiction.
Honeywell reserves the right to make changes to improve reliability, function or design. Honeywell does not assume
any liability arising out of the application or use of any product or circuit described herein; neither does it convey any
license under its patent rights nor the rights of others.
This product may be covered by one or more of the following U.S. Patents: 4569742 4681812 4847584 4857418
4945397 5019461 5247278 5820924 5952825 and 6529114.
900252 10-03 Rev. B
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