HMC1052L-TR Honeywell Microelectronics & Precision Sensors, HMC1052L-TR Datasheet - Page 8

• Manufacturer Part Number: HMC1052L-TR
• Description: MAGNETIC SENSORS
• Manufacturer: Honeywell Microelectronics & Precision Sensors
• Type: Linearr

Specifications of HMC1052L-TR

• Sensing Range: ±6g
• Voltage - Supply: 1.8 V ~ 20 V
• Output Type: Differential Voltage
• Features: Compass - Two Axis
• Operating Temperature: -40°C ~ 125°C
• Package / Case: 16-LCC Exposed Pad (No Lead)
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Current - Supply: -
• Current - Output (max): -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant
• Other names: 342-1042-2

HMC1051/HMC1052/HMC1053
Set/Reset Circuit Notes
The above set/reset circuit in Figure 1using the IRF7507
dual complementary MOSFETs is shown in detail by Figure
2 in its H-bridge driven configuration. This configuration is
used primarily in battery operated applications were the
500mA nominal set/reset pulsed currents can be best
obtained under low voltage conditions.
The 200-ohm resistor trickle charges the 1uf supply
reservoir capacitor to the Vcc level, and isolates the battery
from the high current action of the capacitors and MOSFET
switches. Under conventional logic states one totem pole
switch holds one node of the 0.1uf capacitor low, while the
other switch charges Vcc into the capacitors opposite node.
At the first logic change, the capacitor exhibits almost a
twice Vcc flip of polarity, giving the series set/reset strap
load plenty of pulse current. A restoring logic state flip uses
the 0.1uf capacitors stored energy to create a second nearly
equal but opposite polarity current pulse through the
set/reset strap.
For operation at normal 3.3 or 5-volt logic levels, a single complementary MOSFET pair can be used in a single ended
circuit shown in Figure 4. Other complementary MOSFET pairs can be used with the caution that the chosen devices
should have less than 0.5 ohms ON resistance and be able to handle the needed supply voltages and set/reset currents.
Note that even a 1Hz rate of set/reset function draws an
average current of less than 2 microamperes.
Magnetic Field Detection
For simple magnetic field sensing applications such
Magnetic Anomaly Detectors (MADs) and Magnetometers,
a similar circuit to the compass application can be
implemented using one, two, or three magnetic sensors. In
the example circuit in Figure 5, a HMC1051Z sensor bridge
is used with a low voltage capable dual op-amp to detect
sufficient intensity of a magnetic field in a single direction.
Uses of the circuit include ferrous object detection such as
vehicle detection, a “sniffer” for currents in nearby
conductors, and magnetic proximity switching. By using two
or three sensor circuits with HMC1051, HMC1052, or
HMC1053 parts, a more omni-directional sensing pattern
can be implemented. There is nothing special in choosing the resistors for the differential op-amp gain stages other than
having like values (e.g. the two 5k
interference signals (EMI, RFI). The ratio of the 500k /5k
specific purpose. Typical gain ratios for compass and magnetometer circuits using the HMC105X family, range from 50 to
500. The choice of the 5k
ohms or higher for best voltage transfer or matching. Note that Figure 5 also shows an alternative set/reset strap driver
circuit using two darlington complentary paired BJTs as electronic switches.
8
value sets impedance loading seen by the sensor bridge network and should be about 4 kilo-
and the 500k
resistors) matched at 1% tolerance or better to reject common-mode
resistors sets the stage gain and can be optimized for a
Rset/reset
Rset/reset
Rset/reset
Rset/reset
4
4
4
4
.1 f
.1 f
.1 f
.1 f
D
D
D
D
S
S
S
S
Vsr
Vsr
IRF7509(P)
IRF7509(P)
IRF7509(N)
IRF7509(N)
1 f
1 f
1 f
1 f
G
G
G
G
+
+
+
+
-
-
-
-
D
D
D
D
D
D
D
D
S
S
S
S
S
S
S
S
Vsr
Vsr
Vsr
Vsr
Single-Ended Driver
IRF7509(P)
IRF7509(P)
H-Bridge Driver
IRF7509(N)
IRF7509(N)
www.honeywell.com
IRF7509(N)
IRF7509(N)
IRF7509(P)
IRF7509(P)
G
G
G
G
Figure 4
G
G
G
G
Figure 3
200
200
200
200
set/reset
set/reset
set/reset
set/reset
_set/reset
_set/reset
Vcc
Vcc
Vcc
Vcc