HMC1022 Honeywell Microelectronics & Precision Sensors, HMC1022 Datasheet - Page 11

• Manufacturer Part Number: HMC1022
• Description: Magnetic Sensor
• Manufacturer: Honeywell Microelectronics & Precision Sensors

Specifications of HMC1022

• Sensitivity Range: 1mV/V/G
• Sensor Output: Voltage
• Terminal Type: PCB Thru Hole
• Output Type: Differential
• Sensor Terminals: SMD Gull Wing
• Leaded Process Compatible: No
• Magnetic Field Max: 6G
• Axis Configuration: Two
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Low Power— For low power application, down to 3.3 volt
supply, the circuit shown in Figure 15 can be used. These
low threshold FETs provide low on-resistance (0.3Ω) at
V
continuous. To save power, the SET pulse can be initially
applied followed by a single RESET pulse. The offset (OS)
can be calculated as:
This offset term will contain the DC offset of both the sensor
bridge and interface electronics, as well as the temperature
drift of the bridge and interface electronics. Store this value
and subtract it from all future bridge output readings. Once
the bridge is RESET, it will remain in that state for years—
or until a disturbing field (>20 gauss) is applied. A timer can
be set, say every 10 minutes, to periodically update the
offset term. A flow chart is shown in Figure 14 along with a
timing diagram in Figure 15 to illustrate this process.
GS
=2.7V. The set/reset pulsing does not need to be
T
T
T
T
Reset
Vout
a > 5 µsec
b > 1 µsec
c > 20 µsec, 50 msec(max)
d > 20 µsec
Set
S/R
Clock
S/R
T
OS = (Vset + Vrst)/2
a
5V
Vp
T
4 to14V
b
Figure 15—Single Clock Set/Reset Pulse Circuit (1021/1022)
Figure 13—Set/Reset Pulse With Clock Control (1021/1022)
set
T
a
-4 to -14V
set
T
T
Vp > 3 V
PW ~ 2 µsec
d
T
T
T
Vset
read
PW
c
PW ~ 2 µsec
-Vp
reset
reset
T
d
set rst set
read
Vrst
Clock
LINEAR MAGNETIC FIELD SENSORS
+5 to 6V
11
+3.3 to
6.5V
Reset
Set
4
2
200
Figure 14—Low Power Set/Rst Flowchart
3
1
5,6
7,8
2,4
2,4
IRF7105 (2)
DI9952 (2)
5,6,7,8
5,6,7,8
200
1µF (1)
1,3
1,3
(1) Tantalum, low R
(2) Rds ~0.2 ohm
OS = (Vset+Vrst)/2
NDS9933
NDS8926
Vout = Vrst - OS
0.1µF
RESET Pulse
Read Vset
SET Pulse
Read Vrst
Read Vrst
expired?
+
1µF (1)
14
Timer
n
HMC1022
8
0.1µF
(2) Rds ~0.2 ohm
(1) Tantalum, low R
S/R
y
14
9,15
HMC1022
8
S/R
9,15