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Datasheets:
A1444 and A1445: Low-Voltage Full-Bridge Brushless DC Motor Driver with Hall Commutation, Externally Controlled Speed Regulation, Soft Switching, and Reverse Battery, Short Circuit, and Thermal Shutdown Protection (PDF)

Selection Guides:
Hall-Effect Sensors,

BLDC Motor Drivers with Integrated Hall for Commutation

when this product is updated

Press Releases:
A1444 and A1445: Allegro MicroSystems, Inc. Announces New Low-Voltage Full-Bridge Brushless DC Motor Driver with Integrated Hall

A1444 and A1445
Low-Voltage Full-Bridge Brushless DC Motor Driver with Hall Commutation, Externally Controlled Speed Regulation, Soft Switching, and Reverse Battery, Short Circuit, and Thermal Shutdown Protection

Features and Benefits

• Low voltage operation: 1.8 to 4.2 V
• Externally controlled motor speed regulation
• Fast motor startup and braking function allows faster start-stop cycles
• Reverse voltage protection on the VDD and SLEEP pins
• Output short circuit and thermal shutdown protection
• Soft switching algorithm for reduced audible switching noise and EMI interference
• Unidirectional operating mode results in motor rotation in only one direction
• Chopper stabilization reduces Hall signal offset drifts and results in increased signal accuracy over full operating temperature range
• Sleep mode pin allows device enable/disable for reducing average power consumption
• Antistall feature guarantees continuous rotation
• Single-chip solution for high reliability
• Miniature MLP/DFN package

Description

The A1444 and A1445 are full-bridge motor drivers designed to drive low-voltage brushless DC (BLDC) motors in applications that require rotor speed control and fast rotor start-stop cycles. A high density CMOS semiconductor process allows the integration of a Hall element, a full-bridge output driver, and PWM speed control logic into one monolithic IC. Commutation of the motor is achieved by use of a single Hall element sensor to detect the rotational position of an alternating-pole ring magnet. Low-voltage design techniques have been employed to achieve full device functionality down to a VDD of 1.8 V. The voltage applied to the PDC pin is used to externally control the maximum speed of the motor by adjusting the PWM duty cycle of the output driver.

The A1444 and A1445 employ a soft switching algorithm to reduce audible switching noise and EMI interference. The externally controlled speed regulation and braking functions can be used to create motor designs requiring faster start-stop cycles. The A1444 and A1445 have different selectable internal PWM duty cycle options to accommodate a wide range of motor designs. Each device has a braking function enable pin that also includes a micropower sleep mode for battery management in portable electronic devices. This feature eliminates the requirement for a FET transistor to switch the device on and off.

The devices are optimized for vibration motor applications that require fast start-stop cycles, such as in cellular phones, pagers, and hand-held video game controllers. The devices can also be used for low-power fan motors rated at 5 V. This fully integrated single-chip solution provides enhanced reliability, including reverse battery protection and output short circuit protection.

The small package outline and low profile make this device ideally suited for use in applications where printed circuit board area and component headroom are at a premium. It is available in a lead (Pb) free (leadframe plating nickel palladium) 6-contact MLP/DFN microleadframe package for surface mount assembly. The underside of the package also features an exposed pad for enhanced thermal dissipation.

Functional Block Diagram

Complete Part Numbers

Part Number	Package Type	RoHS Compliant	Part Composition/ RoHS Data	Temperature	Comments	Samples	Distributor Stock
A1444EEWLT-P	6-lead MLP/DFN	Yes	view data	-40 °C to  85 °C	new	Due to warehouse relocation, samples will be unavailable until August 1, 2008. Contact your sales rep or purchase from distributor.
A1445EEWLT-P	6-lead MLP/DFN	Yes	view data	-40 °C to  85 °C	new	Due to warehouse relocation, samples will be unavailable until August 1, 2008. Contact your sales rep or purchase from distributor.

Allegro's products are not to be used in life support devices or systems, if a failure of an Allegro product can reasonably be expected to cause the failure of that life support device or system, or to affect the safety or effectiveness of that device or system.