Diodes AH278 User Manual

Data Sheet

HIGH VOLTAGE HALL EFFECT LATCH AH278

General Description

The AH278 is an integrated Hall sensor with output driver designed for electronic commutation of brushless DC motor applications. The device includes an onchip Hall sensor for magnetic sensing, an amplifier that amplifies the Hall voltage, a Schmitt trigger to provide switching hysteresis for noise rejection and two complementary open-collector drivers for sinking large load current. It also includes an internal band-gap regulator which is used to provide bias voltage for internal circuits and allows a wide operating supply voltage ranges.

Placing the device in a variable magnetic field, if the magnetic flux density is larger than threshold B

pin DO will be turned low (on) and pin DOB will be turned high (off). This output state is held until the magnetic flux density reverses and falls below B

then causes DO to be turned high (off) and DOB turned low (on).

AH278 is available in TO-94 (SIP-4L) package.

OP

, the

RP,

Features

· On-Chip Hall Sensor

· 4V to 30V Supply Voltage

· 500mA (avg) Output Sink Current

· Build in Protection Diode for Reverse Power

Connecting

o

· -20

· Low Profile TO-94 (SIP-4L) Package

· Build in Over Temperature Protection Function

· ESD Rating: 300V(Machine Model)

C to 85oC Operating Temperature

Applications

· 12V/24V Dual-Coil Brushless DC Motor/Fan

· Power Supply and Switchboard

· Communications Facilities

· Industrial Equipment

TO-94

Figure 1. Package Type of AH278

Nov. 2009 Rev. 1. 4 BCD Semiconductor Manufacturing Limited

1

Data Sheet

HIGH VOLTAGE HALL EFFECT LATCH AH278

Pin Configuration

Z4 Package

(TO-94)

Pin Description

Pin Number Pin Name Function

1

2 DO Output 1

3 DOB Output 2

4 GND Ground

4

3

2

1

Figure 2. Pin Configuration of AH278 (Front View)

V

CC

Supply voltage

GND

DOB DO

V

CC

Nov. 2009 Rev. 1. 4 BCD Semiconductor Manufacturing Limited

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Data Sheet

HIGH VOLTAGE HALL EFFECT LATCH AH278

Functional Block Diagram

V

CC

1

Regulator

Over-Temperature

Protection

DO

2

4

GND

Hall

Sensor

Ordering Information

Circuit Type

Package

Z4: TO-94 (SIP-4L)

Amplifier

Figure 3. Functional Block Diagram of AH278

AH278

Schmitt Trigger

-

Output

Driver

E1: Lead Free G1: Green

Magnetic Characteristics A: 10 to 70Gauss B: 100Gauss

3

DOB

Package

TO-94

BCD Semiconductor's Pb-free products, as designated with "E1" suffix in the part number, are RoHS compliant. Products with "G1" suffix are available in green package.

Temperature

Range

o

-20 to 85

C

Lead Free Green Lead Free Green

AH278Z4-AE1 AH278Z4-AG1 AH278Z4-E1 AH278Z4-G1 Bulk

AH278Z4-BE1 AH278Z4-BG1 AH278Z4-E1 AH278Z4-G1 Bulk

Part Number Marking ID

Packing

Typ e

Nov. 2009 Rev. 1. 4 BCD Semiconductor Manufacturing Limited

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Data Sheet

HIGH VOLTAGE HALL EFFECT LATCH AH278

Absolute Maximum Ratings (Note 1)

(TA=25oC)

Parameter Symbol Value Unit

Supply Voltage V

Reverse Protection Voltage V

CC

RCC

30 V

-30 V

Magnetic Flux Density B Unlimited Gauss

Output Current

Continuous

Hold 600 mA

I

O

500 (Note 2) mA

Peak (start up) 800 mA

Power Dissipation P

Die to atmosphere θJA 227

D

550 mW

o

C/W

Thermal Resistance

Die to package case θJC 49

Storage Temperature T

STG

-50 to 150

o

C/W

o

C

ESD (Machine Model) 300 V

Note 1: Stresses greater than those listed under "Absolute Maximum Ratings" may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated under "Recommended Operating Conditions" is not implied. "Absolute Maximum Ratings" for extended period may affect device reliability.

Note 2: Continuos output current is 300mA at 85oC.

Recommended Operating Conditions

Parameter Symbol Min Max Unit

Supply Voltage

Operating Ambient Temperature

V

CC

T

A

Nov. 2009 Rev. 1. 4 BCD Semiconductor Manufacturing Limited

4

428V

-20 85

o

C