Diodes AH1892 User Manual

PROGRAMMABLE MICROPOWER OMNIPOLAR

HALL-EFFECT SENSOR SWITCH

Description

The AH1892 is a micropower magnetic range selectable (Bop/Brp) Omnipolar Hall effect switch IC with internal pull up and pull down capability, designed for consumer equipment ranging from portable and battery powered cellular phones and portable PCs to home appliances and industrial applications. To support battery powered equipment and low voltage microcontrollers, the AH1892 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. Due to the application diversity, the AH1892 has an 8kV ESD rating on the supply and output pins. To minimize PCB space the AH1892 is packaged in the small CSP package (0.71mm x 0.71mm) or SOT553 leaded package

The output is activated with either a north or south pole of sufficient magnetic field strength. The user can select one of two magnetic

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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) is larger than operate point (Bop), the output will be turned on (pulled low) and held until B is lower than release point (Brp).

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

 Superior temperature stability  Extremely Low Switch-Point Drift  Insensitive to Physical Stress

• No external pull up resistors required

• Good RF noise immunity

• -40°C to +85°C operating temperature

• 8kV ESD on supply and output pins

• Miniature U-WLB07070-4 (CSP 0.71mm x 0.71mm typical) and small low profile SOT553

• 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.

AH1892

Document number: DS35092 Rev. 1 - 2

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.

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Pin Assignments

U-WLB0707-4

SOT553

Applications

• Open and close detect for gaming and cellular phones

• Holster and dock detect for cellular phones

• Cover switch in portable and tablet PCs

• Digital still and video cameras

• Tray, door and covers position detect for printers and scanners

• Contact-less switch in consumer and industrial products

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Typical Application Circuit

AH1892

PROGRAMMABLE MICROPOWER OMNIPOLAR

HALL-EFFECT SENSOR SWITCH

Note : C

is for power stabilization and to strengthen the noise immunity, the recommended capacitance is 100nF typical

Pin Descriptions

Package: U-WLB0707-4

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Pin # Pin Name Description

A1 GND Ground A2 OUTPUT Output B1 BSEL Band Select

Package: SOT553

Pin # Pin Name Description

1 2 NC No Connection (Note 4) 3 BSEL Band Select 4 GND Ground 5 OUTPUT Output

Notes: 4. NC is “No Connection” pin and is not connected internally. This pin can be left open or connected to ground.

Power Supply Voltage

Functional Block Diagram

AH1892

Document number: DS35092 Rev. 1 - 2

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AH1892

Absolute Maximum Ratings (T

Symbol Characteristics

VDD

DD REV

OUTPUT

B Magnetic Flux Density Unlimited

Ts Storage Temperature Range -65 to +150 °C

ESD Human Body Model ESD

Notes: 5. Stresses greater than the 'Absolute Maximum Ratings' specified above, may cause permanent damage to the device. These are stress ratings

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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

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

Recommended Operating Conditions

Symbol Characteristics Conditions Rating Unit

VDD

Supply Voltage Operating 1.6 to 3.6 V

Operating Temperature Range Operating -40 to +85 °C

Electrical Characteristics (T

Symbol Characteristics Conditions Min Typ Max Unit

VOL

VOH

BLsel Band select low band 0 0.5 V

BHsel Band select high band 1.4 3.6 V

U_BSEL

IDD(awake)

IDD(sleep)

IDD(avg) IDD(avg) VDD = 3.6V Tawake Awake active pulse width (Note 8) 50 100 µs

Tperiod Awake period (Note 8) 50 100 ms

D.C. Duty cycle 0.1 %

TBand Band transition time ( Note 9) 100.0 200.1 ms

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).

AH1892

Document number: DS35092 Rev. 1 - 2

Output low voltage (on) Output high voltage (off)

BSEL pin internal pull-up resistor (Note 7) 50 kΩ

Supply current

Average cupply current

8. When power is initially on, the operating V

9. Transition time varies dependant on the timing of BSEL activation during the sleep and awake phases.

= +25°C, Note 5)

= +25°C, V

(1.6V to 3.6V) must be applied to guarantee the output sampling.

PROGRAMMABLE MICROPOWER OMNIPOLAR

HALL-EFFECT SENSOR SWITCH

alues Unit

U-WLB0707-4 160 mW SOT553 230 mW

, GND and OUT pins

BSEL pin 6 kV

= 1.8V, unless otherwise specified.)

= 1mA

OUT

= -1mA V

OUT

During ‘awake’ period 2.1 mA

During ‘sleep’ period 2.5 µA

VDD = 1.8V

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0.1 0.2 V

-0.2 V

4.3 8.0 µA

7.2 13.0 µA

8 kV

-0.1

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AH1892

Electrical Characteristics (cont.)

IDD(awake)

IDD(sleep)

Magnetic Characteristics (T

(1mT=10 Gauss)

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BSEL Symbol Characteristics Min Typ Max Unit

Low Low Low

Low High High High High

Notes: 10. Magnetic characteristics may vary with operating temperature and after soldering.

The AH1892 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 AH1892 sensitivity to be changed by firmware within the application without the addition of any external components. If the BSEL pin is left open circuit the AH1892 defaults to high band.

BopsLB(south pole to brand side) BopnLB (north pole to brand side) BrpsLB (south pole to brand side) BrpnLB (north pole to brand side) BopsHB(south pole to brand side) BopnHB (north pole to brand side) BrpsHB (south pole to brand side) BrpnHB (north pole to brand side)

- Bhy (|Bopx|-|Brpx|) Hysteresis - 10 -

AH1892

Document number: DS35092 Rev. 1 - 2

= +25°C, V

PROGRAMMABLE MICROPOWER OMNIPOLAR

HALL-EFFECT SENSOR SWITCH

Tperiod

Tawake

Tsleep

Sample and output

latched

= 1.6V to 3.6V, Note 10)

Low Band - Operation Point

Low Band - Release Point

High Band - Operation Point

High Band - Release Point

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18 35 55

-55 -35 -18 12 25 45

-45 -25 -12 43 60 80

-80 -60 -43 35 50 70

-70 -50 -35

Gauss

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