HMC1051Z Honeywell, HMC1051Z Datasheet - Page 4

• Manufacturer Part Number: HMC1051Z
• Manufacturer: Honeywell

Specifications of HMC1051Z

• Lead Free Status / Rohs Status: Compliant

HMC1051Z / HMC1052
Basic Device Operation
The HMC1051 and HMC1052 are single-axis and two-axis linear magnetic sensors designed as a Wheatstone
bridges formed by a magnetoresistive metal film. With the power supply applied to the bridge, the sensors converts
any incident magnetic field in the sensitive direction to a balanced voltage output. The magnetoresistive sensors are
made of a nickel-iron (Permalloy) thin-film deposited on a silicon wafer in pattern of resistive strips. In the presence of
a magnetic field, a change in the bridge resistive elements causes a corresponding change in voltage across the
bridge outputs.
In addition to the bridge circuits, the sensors each have two on-chip magnetically coupled straps; the Offset Strap and
the Set/Reset Strap. The patented straps eliminate the need for external coils surrounding the bridge elements. The
offset strap (available on bare die only) allows for several modes of operation when a direct current is driven through
it. These modes are: 1) Subtraction of an unwanted magnetic field, 2) Zero-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.
Application Notes
Low Cost 2-Axis Compass
Very high precision measurements can be made using the HMC1051 and HMC1052 sensors when interfaced with
low noise amplifiers and 12 to 16-bit Analog-to-Digital (A/D) converters. For lower resolution (1°) or low cost compass
applications, 8 or 10-bit A/D converters may be used with general purpose operational amplifiers. Figure 1 shows a
typical 2-axis compassing application using readily available off-the-shelf components.
The basic principle of two-axis compassing is to orient the sensor bridge element horizontal to the ground
(perpendicular to the gravitational field) and to measure the X and Y analog voltages. With the amplified sensor bridge
voltages near-simultaneously converted (measured) to their digital equivalents, the arc-tangent Y/X can be computed
to derive the heading information. See the application notes on compassing at Honeywell Magnetic Sensors website
(www.magneticsensors.com) for basic principles and detailed application information.
Solid State Electronics Center • www.magneticsensors.com • [phone] • Page 4
2.5 to 3.6v
Vcc
set/reset
offset
U1
HMC1052
.1uf
Figure 1
5.00k
5.00k
5.00k
5.00k
(2) IRF7507
500k
500k
1nf
1nf
Vref/2
Vref/2
LMV358
LMV358
U4
U5
500k
500k
U2
set/reset
_set/reset
1
0
MAX1118
U3
Vref
enable
data_out
clk_in
SENSOR PRODUCTS