Diodes AH1802 User Manual

MICROPOWER, ULTRA-SENSITIVE OMNIPOLAR

HALL-EFFECT SENSOR SWITCH

Description

The AH1802 is a ultra-sensitivity, micropower Omnipolar Hall Effect switch IC designed for portable and battery powered equipment such as cellular phones, PDA’s and portable PC’s. Based on two sensitive Hall Effect plates and a chopper stabilized architecture the AH1802 provides a reliable solution over the whole operating range. T o support portable and battery powered equipment the design has been optimized to operate over the supply range of 2.5V to 5.5V and consumes only 24uW with a supply of 3V.

The single open drain output can switched on with either a north or south pole of sufficient strength. When the magnetic flux density (B) is larger than operate point (Bop) the output is switched on (pulled low). The output is turned off when B becomes lower than the release point (Brp). The output will remain off when there is no magnetic field.

Features

• Omni-polar (north or south pole) operation

• High sensitivity

• Single open drain output

• Micropower operation

• 2.5V to 5.5V operating range

• Chopper stabilized design provides

• Superior temperature stability

• Minimal switch point drift

• Enhanced immunity to stress

• Good RF noise immunity

• -40°C to 85°C operating temperature

• ESD＞5kV for DFN2020-6, DFN2020-3 and DFN2015H4-3

ESD＞6kV for SC59

• Low profile SC59, DFN2020-6, DFN2020-3 and DFN2015H4-3 packages

• “Green” Molding Compound (Note 1)

Notes: 1. EU Directive 2002/95/EC (RoHS). All applicable RoHS exemptions applied. Please visit our website at http://www.diodes.com/products/lead_free.html.

Pin Assignments

(Top View)

2. Output

GND 3.

SC59

(Top View)

1. Vdd

DFN2020-3

1. Vdd

3. GND

3. Output

Applications

• Cover switch in clam-shell or slide type cellular phones

• Display switch for portable PCs

• On/Off switch for PDAs and digital cameras

• Contact-less switch in consumer products

AH1802

(Top View)

5. GND

4. NC6. NC

1. Vdd 2. NC 3. Output

DFN2020-6

(Top View)

3. GND

1. Vdd 2. Output

DFN2015H4-3

AH1802

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Typical Application Circuit

C

AH1802

MICROPOWER, ULTRA-SENSITIVE OMNIPOLAR

HALL-EFFECT SENSOR SWITCH

2.5~5.5V

R

L

Output

AH1802

GND

Pin Descriptions

Pin Name P/I/O Description

Vdd P/I Power Supply Input

GND P/I Ground

Output O Output Pin

NC No connection (Note 2)

Notes: 2. NC is “No Connection”- recommendation is to connect the NC pin to ground externally.

Functional Block Diagram

1

Power switch

Latch

Hall Plate

Cancelling

Offset

Amp

Cancelling

Offset

Amp

Vdd

Logical

Output

3

GND

2

AH1802

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AH1802

V

MICROPOWER, ULTRA-SENSITIVE OMNIPOLAR

HALL-EFFECT SENSOR SWITCH

Absolute Maximum Ratings (T

Symbol Characteristics

Vdd Supply Voltage 7 V

B Magnetic Flux Density Unlimited Ts Storage Temperature Range -65 to +150 PD Package Power Dissip ation 230 mW

TJ

Maximum Junction Temperature 150

Recommended Operating Conditions (T

Symbol Parameter Conditions Rating Unit

Vdd Supply Voltage Operating 2.5 to 5.5 V

TA Operating Temperature Range Operating -40 to +85

Electrical Characteristics (T

Symbol Characteristic Conditions Min Typ. Max Unit

Vout Output On Voltage Iout=1mA - 0.1 0.3 V

Ioff Output Leakage Current Vout=5.5V, B < Brp -

Idd(en)

Idd(dis)

Idd(avg)

FC Chopping Frequency For design information only - 300 - KHz

Tawake Awake Time (Note 3) - 75 150 µs

Tperiod Period (Note 3) - 75 150 ms

D.C. Duty Cycle - 0.1 - %

Notes: 3. When power is initially turned on, Vdd must be within its correct operating range (2.5V to 5.5V) to guaranteed the output sampling. The output state is valid after the second operating cycle (typical 150ms).

Supply Current

= 25°C)

A

= 25°C)

A

= 25°C, Vdd = 3V; unless otherwise specified)

A

Chip enable, T Chip enable, TA= -40~85°C,

Vdd = 2.5~5.5V Chip disable, T Chip disable, TA= -40~85°C,

Vdd = 2.5~5.5V Average supply current , TA= 25°C, Vdd = 3V Average supply current ,

= -40~85°C, Vdd = 2.5~5.5V

T

A

= 25°C, Vdd = 3V

A

= 25°C, Vdd = 3V

A

- 3 6 mA

- 3 10 mA

- 5 10 µA

- 5 18 µA

- 8 16 µA

- 8 23 µA

alues Unit

°C

<0.1

1 µA

Tperiod

Tawake

Idd(en)

Sample and output latched

Idd (dis)

0

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MICROPOWER, ULTRA-SENSITIVE OMNIPOLAR

HALL-EFFECT SENSOR SWITCH

Magnetic Characteristics (T

Symbol Characteristic Min Typ. Max Unit

Bops(south pole to brand side) Bopn(north pole to brand side) -40 -28 -20

Brps(south pole to brand side) Brpn(north pole to brand side) - -20 -10

Bhy( BrpxBopx − )

Notes: 4. Typical data is at TA = 25°C, Vdd = 3V, and for design information only.

5. The magnetic characteristics may vary with supply voltage, operating temperature and after soldering.

= 25°C, Vdd = 3V, Note 4 & 5)

A

Operate Point

Release Point

Hysteresis 5 8 -

Output

20 28 40

10 20 -

Output

AH1802

(1mT=10 Gauss)

Gauss

Vcc

Turn on

( Output Voltage )

( on-state )

( Magnetic flux density B )

AH1802

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( off-state )

Bhy

Bopn Brpn 0

Turn off

Vsat

( Output Voltage )

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Turn off

( off-state )

Bhy

Vcc

Turn on

( on-state )

Vsat

Brps Bops0

( Magnetic flux density B )

December 2010