ADLxxx Nanopower Digital Switches
ADLxxx Nanopower Digital Switches
Functional Diagrams
V
DD
Out
GMR
Sensor
Element
Comparator
Features
•
2.4 V
−
3.6 V operating voltage
•
Continuously operating or duty-cycled versions
•
Power as low as 150 nW at 2.4 V
•
Operate points as low as 20 Oe
•
Precise detection of low magnetic fields
•
Ultraminiature 1.1 x 1.1 mm package
GND
ADL9xx
(continuous duty)
Applications
•
Portable instruments
•
Utility meters
•
Lithium cell powered applications
V
DD
Oscillator
and
Timing
Out
GMR
Sensor
Element
Comparator
Latch
Description
ADLxxx-Series sensors are Giant Magnetoresistive (GMR)
Digital Switch devices designed to operate from
3.3-volt power supplies or single lithium cells with
extremely supply low currents. The devices are
manufactured with NVE’s patented spintronic GMR
technology and low-power CMOS circuitry for unmatched
miniaturization, sensitivity, precision, and low power.
The output is configured as a magnetic “switch” where the
output turns on when the magnetic field is applied, and turns
off when the field is removed. Versions are available that are
either continuous duty or internally duty cycled operation to
further reduce power consumption. An integrated latch
ensures the output is available continuously in duty-cycled
versions.
The applied field can be of either polarity, and the operate
point is extremely stable over supply voltage and
temperature. The output is current-sinking, and can sink up
to 100 microamps.
GND
ADL0xx
(duty-cycled)
Idealized Magnetic Response
NVE Corporation
11409 Valley View Road, Eden Prairie, MN 55344-3617
Phone: (952) 829-9217
www.nve.com
©NVE Corporation
ADLxxx Nanopower Digital Switches
Absolute Maximum Ratings
Parameter
Supply voltage
Output voltage
Output current
Storage temperature
Junction temperature
Applied magnetic field
Min.
Max.
5.5
5.5
200
135
135
Unlimited
Units
Volts
Volts
μA
°C
°C
−65
Operating Specifications
Parameter
Supply voltage
Operating temperature
Magnetic operate point
ADLx21
ADLx24
Operate/release differential
Quiescent current
ADL1xx
ADL0xx
ADL9xx
ADL1xx
ADL0xx
ADL9xx
ADL0xx / ADL1xx peak supply current
Output drive current
Output low voltage
Output leakage current
Update frequency
ADL1xx
ADL0xx
Frequency response (ADL9xx)
T
min
to T
max
; 2.4 V < V
DD
< 3.6 V unless otherwise stated.
Symbol
Min.
Typ.
Max.
V
DD
2.4
3
3.6
T
MIN
; T
MAX
−40
125
H
OP
H
OP
−H
REL
15
21
2
20
28
0.06
0.13
35
0.25
0.35
85
60
100
0.2
0.005
10
20
30
55
100
25
34
14
0.12
0.26
50
0.38
0.65
120
100
Units
Volts
°C
Oe
Oe
V
DD
= 2.4V
μA
V
DD
= 3.6V
μA
μA
V
μA
Hz
kHz
V
DD
= 3V
V
DD
= 3.6V;
I
OL-ON
= 100
μA
Test Condition
I
DDQ
I
DD-PK
I
OL-ON
V
OL
I
OL-OFF
2
NVE Corporation
11409 Valley View Road, Eden Prairie, MN 55344-3617
Phone: (952) 829-9217
www.nve.com
©NVE Corporation
ADLxxx Nanopower Digital Switches
Operation
Direction of Magnetic Sensitivity
As the field varies in intensity, the digital output will turn on and off. Unlike Hall effect or other sensors, the direction of
sensitivity is in the plane of the package. The diagrams below show two permanent magnet orientations that will activate the
sensor in the direction of sensitivity:
Figure 1. Direction of magnetic sensitivity.
ADL-Series sensors are “omnipolar,” meaning the outputs turn ON when a magnetic field of either magnetic polarity is applied.
External Pull-Up Resistor
Outputs are logic low when the sensor is activated. The outputs are open-drain, and should have an external pull-up resistor. For
microcontroller interfaces, the microcontroller’s input pull-up resistors can be activated.
Typical Operation
Figure 2 shows typical ADL-Series sensor orientation. The arrow on the circuit board shows the direction of magnetic sensitivity:
ADL-Series Sensor
Figure 2. Typical operation; the circuit board arrow shows direction of sensitivity.
Typical magnetic operate and release distances for an inexpensive 4 mm diameter by 6 mm thick ceramic disk magnet, are
illustrated in the following table:
Operate
Point
(typ.)
20 Oe
28 Oe
Operate
Distance
(typ.)
10 mm
9 mm
Release
Distance
(typ.)
12 mm
11 mm
Part
ADLx21-14E
ADLx24-14E
Larger and stronger magnets allow farther operate and release distances. For more calculations, use our digital sensor switching
versus distance Web application at:
www.nve.com/spec/calculators.php.
3
NVE Corporation
11409 Valley View Road, Eden Prairie, MN 55344-3617
Phone: (952) 829-9217
www.nve.com
©NVE Corporation
ADLxxx Nanopower Digital Switches
Illustrative Application Circuits
Direct-Drive LED Indicator
Although ADLxxx-14E series sensors are not capable of driving legacy LEDs, high-efficiency LEDs such as the APT3216LSECK
are visible with the 100µA drive current provided by the sensors without an external driver.
This circuit illustrates a sensor powered by a single lithium button cell with a surface-mount indicator LED:
2
APT3216
LSECK
10K
3
3V
BR1225
4
ADL9xx-14E
Figure 3. Typical ADLxxx-14E application.
Two-Wire Sensor Interface Using a Voltage Regulator
ADL-Series sensors are perfect for two-wire applications, because their low supply voltage and low quiescent current provide
plenty of design margin. Two-wire interfaces need to operate over a wide power supply range. With the sensor off, the circuit must
draw a minimal residual current, typically less than 1.5 milliamps. With the sensor on, the circuit must provide enough current to
drive a significant load such as a motor or solenoid:
ADL924-14E
V
DD
3.3 V
200K
DC
001-10
Out
a
b
300
IRLML
5103
LOAD
80 mA
max.
V+
5-30 V
NC7S
14M5X
Gnd
IRLML
6346
MMSZ
4685
(3.6 V)
V-
a. GMR Bridge b. Comparator
Figure 4. Typical two-wire circuit.
In this circuit, when a magnetic field is applied to the sensor, the MOSFETs turn on, turning on the LED and powering the load.
This circuit uses an NVE DC001-10 regulator, which provides better regulation and operating latitude over the input voltage range
than a Zener diode.
With no magnetic field and the sensor off, the residual current of the circuit is dominated by the DC001 regulator’s quiescent
current, which is less than one milliamp and relatively constant over input voltage. The Zener diode provides enough voltage to
power the circuitry when the load is powered.
4
NVE Corporation
11409 Valley View Road, Eden Prairie, MN 55344-3617
Phone: (952) 829-9217
www.nve.com
©NVE Corporation
ADLxxx Nanopower Digital Switches
Typical Performance
Average current increases with supply voltage but remains extremely low. The magnetic operate and release points are stable over
temperature and supply voltage. Update frequency increases somewhat with supply voltage.
350
300
Applied Field (Oe)
40
30
20
10
0
-10
-20
-30
Release Point
Operate Point
-40
-25
-10
5
20
35
50
65
80
95
110 125
Operate Point
Release Point
Supply Current (nA)
250
200
150
100
2.4
2.6
2.8
3
3.2
Supply Voltage
3.4
3.6
-40
Temperature (ºC)
Figure 5. Typical supply current
vs. supply voltage (ADL0xx; 25°C).
Figure 6. Typical magnetic operate and release
points vs. temperature (ADLx24; Vdd=3V).
60
Update Frequency (Hz)
33
32
Magnetic Field (Oe)
50
31
30
29
28
27
26
40
30
20
2.4
2.6
2.8
3
3.2
Supply Voltage
3.4
3.6
25
2.4
2.6
2.8
3
3.2
Supply Voltage
3.4
3.6
Figure 7. Typical update frequency
vs. supply voltage (ADL0xx; 25°C).
Figure 8. Typical magnetic operate point
vs. supply voltage (ADLx24; 25°C).
NVE Corporation
11409 Valley View Road, Eden Prairie, MN 55344-3617
Phone: (952) 829-9217
www.nve.com
©NVE Corporation
