Diodes AH1898 User Manual

A

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 = +25C, 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)

A

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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H1898

Application Note

Applications Circuit One – Low Band

Connecting the BSEL pin to ground permanently configures the AH1898 into its high sensitivity mode, requiring a reduced magnetic flux density

to activate its output (Low Band).

Applications Circuit Two – High Band

Connecting the BSEL pin to VDD or to a voltage greater than 1.4V or leaving the BSEL pin unconnected configures the AH1898 into its low

sensitivity mode, requiring a higher magnetic flux density to activate its output (High Band).

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Applications Circuit Three – Adjustable Sensitivity

To enhance flexibility within the application, the sensitivity can be adjusted with a standard logic signal allowing it to be controlled by a micro-

controller or a logic source. This allows the sensitivity to be changed within the application without a hardware change. Whenever the sensitivity

band selection is changed, the band selection changeover should be allowed to complete for the output to be valid.

AH1898

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H1898

Application Note (cont.)

Bands Select Change Timing and Valid Output

Whenever band selection BSEL pin input is changed, allow for band selection changeover to complete and stabilize. The output is valid only

after the second complete operating ‘awake’ phase. Time taken for the output to be valid, after the BSEL change, depends on timing of BSEL

change during the sleep and awake phase; this transition time (t

) can range from 100ms typical and 200.1ms maximum.

BAND

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AH1898

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Typical Operating Characteristics

Typical switch points characteristics in low band (BSEL = Low) and high band (BSEL = High)

VDD= 1.80V, BSEL = Low (GND)

80

60

40

20

0

-20

Gauss (G )

-40

-60

-80

‐50 ‐25 0 25 50 75 100

Temperature (Ԩ )

Switch Points vs. Temperature

Bops
Brps
Bhy

Brpn

Bopn

VDD= 1.80V, BSEL = High (VDD)

80

60

40

20

0

-20

Gauss (G)

-40

-60

-80

-50 -25 0 25 50 75 100

Switch Points vs. Temperature

Temperature (Ԩ)

H1898

Bops
Brps

Bhy

Brpn

Bopn

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VDD= 3.30V, BSEL = Low (GND)

80

60

40

20

0

-20

Gauss (G )

-40

-60

-80

-50-250 255075100

Temperature (Ԩ )

Switch Points vs. Temperature

Bops
Brps
Bhy

Brpn

Bopn

TA= +25oC, BSEL = Low (GND)

80

60

40

20

0

-20

Gauss (G)

-40

-60

-80

1.5 1.8 2.1 2.4 2.7 3 3.3 3.6 3.9

Supply voltage (V)

Switch Points vs. Supply Voltage

Bops
Brps

Bhy

Brpn
Bopn

VDD= 3.30V, BSEL = High (VDD)

80

60

40

20

0

‐20

Gauss(G)

‐40

‐60

‐80

-50 -25 0 25 50 75 100

Bops
Brps

Bhy

Brpn
Bopn

Temperature (Ԩ )

Switch Points vs. Temperature

TA= +25oC, BSEL = High (VDD)

80

60

40

20

0

‐20

Gauss(G)

‐40

‐60

‐80

1.5 1.8 2.1 2.4 2.7 3 3.3 3.6 3.9

Bops

Brps

Bhy

Brpn

Bopn

Supplyvoltage(V)

SwitchPointsvs.SupplyVoltage

AH1898

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Typical Operating Characteristics (cont.)

Average Supply Current I

VDD= 1.80V and 3.60V

10

9

8

(avg) (uA)

7

DD

6

5

4

3

2

1

0

-50 -25 0 25 50 75 100

Avg. Supply Current I

Average Supply Current vs. Temperature

(avg)

DD

Temperature (Ԩ )

3.6V

1.8V

TA= +25oC

10

9

8

(avg) (uA)

7

DD

6

5

4

3

2

1

0

1.5 1.8 2.1 2.4 2.7 3 3.3 3.6 3.9

Avg. Supply Current I

Supply voltage (V)

Average Sup ply C urrent vs. Supply Voltage

H1898

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Ordering Information

Part Number

AH1898-CA4-7 CA4 U-WLB0808-4 3000/Tape & Reel -7

Marking Information

(1) Package Type: U-WLB0808-4

Package

Code

Packaging

7” Tape and Reel

Quantity Part Number Suffix

AH1898

Document number: DS36028 Rev. 1 - 2

Part Number Package Identification Code

AH1898-CA4-7 U-WLB0808-4 B8

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Package Outline Dimensions (All dimensions in mm.)

Please see AP02002 at http://www.diodes.com/datasheets/ap02002.pdf for latest version.

(1) Package Type: U-WLB0808-4

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PIN#1 I

D

A

2

D

e

E

A

A

3

SEATING PLANE

e

Øb ︵X

H1898

U-WLB0808-4

Dim Min Max Typ

A 0.511 REF

4

︶

A2 0.336 0.366 0.351
A3 0.15 0.17 0.16

b 0.205 0.225 0.215
D 0.795 0.825 0.81
E 0.795 0.825 0.81
e - - 0.40

All Dimensions in mm

Sensor Location

Suggested Pad Layout

Please see AP02001 at http://www.diodes.com/datasheets/ap02001.pdf for the latest version.

(1) Package Type: U-WLB0808-4

ØD 4X

C

AH1898

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U-WLB0808-4

Dimensions Value

C 0.40
D 0.172

All Dimensions in mm

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Taping Orientation

Package Type: U-WLB0808-4

H1898

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AH1898

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H1898

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INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
(AND THEIR EQUIVALENTS UNDER THE LAWS OF ANY JURISDICTION).

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2. support or sustain life and whose failure to perform when properly used in accordance with instructions for use provided in the

IMPORTANT NOTICE

LIFE SUPPORT

AH1898

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