This part has been discontinued. Samples are no longer available.
Date of status change: March 4, 2013.
Recommended Substitutions: For existing customer transition, and for new customers or new applications, contact Allegro Sales.
The A1448 is a full-bridge motor driver designed to drive low-voltage, brushless DC motors. The device is designed to allow the user to control several functions with a single input control pin. The pin allows for direct input PWM for speed control, is used to initiate the active braking function to reduce motor stop time, and acts as an enable pin to engage micro-power sleep mode to reduce average power consumption when not in use. The A1448 is designed for use in vibration motor applications in portable devices that require fast stop-start cycles, such as haptic applications and vibration ring tones.
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. A high density CMOS semiconductor process allows the integration of all the necessary electronics. This includes the Hall element sensor, the motor control circuitry, and the output full bridge. Low voltage design techniques have been employed to achieve full device functionality down to 1.8 V VDD. This fully integrated single chip solution provides enhanced reliability (including reverse battery protection and output short circuit protection) and eliminates the need for any external support components.
The A1448 employs a soft-switching algorithm to reduce audible switching noise and EMI interference. The micropower sleep mode can be initiated on the CONTROL pin, and reduces current consumption for battery management in portable electronic devices. This feature allows the removal of a FET transistor for switching the device on and off.
The A1448 is optimized for vibration motor applications in cellular phones, pagers, electronic toothbrushes, hand-held video game controllers, and can also be used as a micro-fan driver for fans motors up to 1 W.
The Allegro DFN (EW) package is the thinnest DFN in the industry with a 0.40 mm maximum thickness that allows for very thin BLDC coin motor designs. 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, 6-contact MLP/DFN micro-leadframe package, with an exposed pad for enhanced thermal dissipation. Leadframe is 100% matte tin plated.
