Diodes AH1898 User Manual
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PROGRAMMABLE MICROPOWER OMNIPOLAR HALL-EFFECT SWITCH
Description
The AH1898 is a micropower magnetic range selectable (Bop/Brp)
Omnipolar Hall effect switch IC with internal pull up and pull down
capability, designed for portable and battery powered consumer
equipment such as cellular phones and portable PCs. To support
battery powered equipment and low voltage microcontrollers, the
AH1898 can operate over the supply range of 1.6V to 3.6V and uses
a hibernating clocking system to minimize the power consumption.
The average supply current is only 4.3µA typical at 1.80V. The
AH1898 has an 8kV ESD rating on the supply and output pins. To
minimize PCB space the AH1898 is packaged in the small
CSP package (0.81mm x 0.81mm typical).
The output is activated with either a north or south pole of sufficient
magnetic field strength. The user can select one of two magnetic
sensitivity bands via the BSEL pin without the addition of any external
components allowing a flexible but small solution. The band select
can be hardwired or be changed on the fly via a logic source such as
a micro-controller. When the magnetic flux density (B) perpendicular
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to the package is larger than operate point (Bop), the output will be
turned on (pulled low) and held until B is lower than release point
(Brp). The output will remain off when there is no magnetic field.
Pin Assignments
(Top View) (Bottom View)
U-WLB0808-4
H1898
Features
Omnipolar Operation (North or South pole)
Programmable Operate and Release Points
Supply Voltage of 1.6V to 3.6V
Micropower Operation
Chopper Stabilized Design Provides
Superior Temperature Stability
Minimal Switch Point Drift
Enhanced Immunity to Physical Stress
No External Pull-up Resistors Required
Good RF Noise Immunity
-40°C to +85°C Operating Temperature
8kV Human Body Model ESD Capability
Miniature U-WLB0808-4 (CSP 0.81mm x 0.81mm typical)
Totally Lead-Free & Fully RoHS Compliant (Notes 1 & 2)
Halogen and Antimony Free. “Green” Device (Note 3)
Notes: 1. No purposely added lead. Fully EU Directive 2002/95/EC (RoHS) & 2011/65/EU (RoHS 2) compliant.
2. See http://www.diodes.com for more information about Diodes Incorporated’s definitions of Halogen- and Antimony-free, "Green" and Lead-free.
3. Halogen- and Antimony-free "Green” products are defined as those which contain <900ppm bromine, <900ppm chlorine (<1500ppm total Br + Cl)
and <1000ppm antimony compounds.
Applications
Open and Close Detect for Cellular Phones
Holster or Cover Detect for Cellular Phones and Tablet PCs
Cover or Display Switch in Portable PCs
Digital Still, Video Cameras and Handheld Gaming Consoles
Proximity and Position Switches
AH1898
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Typical Applications Circuit
H1898
Note: 4. CIN is for power stabilization and to strengthen the noise immunity, the recommended capacitance is 100nF typical.
Pin Descriptions
Package: U-WLB0808-4
Pin Number Pin Name Function
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A1 BSEL Band Select Pin to select operating and release gauss points
A2 GND Ground Pin
B1
B2 OUTPUT Output Pin
V
DD
Power Supply Input
Functional Block Diagram
AH1898
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H1898
Absolute Maximum Ratings (Note 5) (@T
Symbol Parameter Rating Unit
VDD
V
DD_REV
I
OUTPUT
B Magnetic Flux Density Unlimited
PD
Ts Storage Temperature Range -65 to +150 °C
TJ
ESD HBM Human Body Model (HMB) ESD capability
Notes: 5. Stresses greater than the 'Absolute Maximum Ratings' specified above may cause permanent damage to the device. These are stress ratings only;
functional operation of the device at these or any other conditions exceeding those indicated in this specification is not implied. Device reliability may be
affected by exposure to absolute maximum rating conditions for extended periods of time.
6. The absolute maximum V
operate the device at the absolute maximum rated conditions for any period of time.
Supply Voltage (Note 6) 6 V
Reverse Supply Voltage -0.3 V
Output Current (source and sink) 2.5 mA
Package Power Dissipation U-WLB0808-4 160 mW
Maximum Junction Temperature 150 °C
of 6V is a transient stress rating and is not meant as a functional operating condition. It is not recommended to
DD
Recommended Operating Conditions (@T
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Symbol Parameter Conditions Rating Unit
VDD
TA
Electrical Characteristics (@T
Symbol Parameter Conditions Min Typ Max Unit
VOL
VOH
V
SEL_LB
V
SEL_HB
R
PU_BSEL
IDD(awake)
IDD(sleep)
IDD(avg)
Tawake Awake Time (Note 8) — 50 100 µs
Tperiod Period (Note 8) — 50 100 ms
D.C. Duty Cycle — 0.1 — %
t
BAND
Notes: 7. BSEL pin internal pull-up resistor is only active during AWAKE time.
The output state is valid after the second operating phase (typical 100ms).
Supply Voltage Operating 1.6V to 3.6V V
Operating Temperature Range Operating -40 to +85
= +25°C, VDD = 1.8V, unless otherwise specified.)
A
Output Low Voltage (on)
Output High Voltage (off)
Bans select voltage for low band 0 —
Bans select voltage for high band 1.4 —
BSEL pin internal pull-up resistor (Note 7) —
Supply Current
Average Supply Current
Band transition time (Note 9) —
8. When power is initially turned on, the operating V
9. Transition time varies dependant on the timing of BSEL activation during the sleep and awake phases.
= +25°C, unless otherwise specified.)
A
, GND and OUT pins
V
DD
BSEL pin 6 kV
= +25°C, unless otherwise specified.)
A
I
= 1mA
OUT
I
= -1mA V
OUT
— 0.1 0.2 V
DD
8 kV
-0.2 V
DD
-0.1
0.5 V
3.6 V
50 — kΩ
During ‘awake’ period — 2.1 — mA
During ‘sleep’ period —
= 1.8V
V
DD
VDD = 3.6V
2.5 — mA
4.3 8 µA
—
7.2 13 µA
—
100.0 200.1 ms
(1.6V to 3.6V) must be applied to guarantee the output sampling.
DD
C
— V
AH1898
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Magnetic Characteristics (Note 10 & 11) (T
BSEL Symbol Characteristics Min Typ Max Unit
Low
Bops
(south pole to part marking side side)
LB
Low
Bopn
(north pole to part marking side side)
LB
Low
Brps
(south pole to part marking side side)
LB
Low
Brpn
(north pole to part marking side side)
LB
High
Bops
(south pole to part marking side side)
HB
High
Bopn
(north pole to part marking side side)
HB
High
Brps
(south pole to part marking side side)
HB
High
Brpn
(north pole to part marking side side)
HB
Bhy (|Bopx|-|Brpx|) Hysteresis — 10 —
Notes: 10. Typical data is at TA = +25C, VDD = 1.8V.
The AH1898 includes a band select pin (BSEL) so that the operate (Bops and Bopn) and release (Brps and Brpn) points can be adjusted between
two pre-defined ranges. The BSEL can be hard wired within the application circuit or the band can be selected on the fly by using the BSEL pin as
a logic input. This feature allows the AH1898 sensitivity to be changed by firmware within the application without the addition of any external
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components. If the BSEL pin is left open circuit the AH1898 defaults to high band.
11. Magnetic characteristics may vary with operating temperature and after soldering.
= +25°C, VDD = 1.6V to 3.6V, unless otherwise specified)
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Low Band - Operation Point
Low Band - Release Point
High Band - Operation Point
High Band - Release Point
18 35 55
-55 -35 -18
12 25 45
-45 -25 -12
43 60 80
-80 -60 -43
35 50 70
-70 -50 -35
(1mT=10 Gauss)
H1898
Gauss
AH1898
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