A1448

• Low-voltage operation, 1.8 to 4.2 V
• Multifunction CONTROL pin input:
  • Direct input PWM for speed control
  • Active braking for fast stop cycle
  • Sleep function to reduce average power consumption
• Reverse voltage protection on VDD and CONTROL pins
• Output thermal shutdown protection for robust performance
• Soft switching algorithm to reduce audible switching noise and EMI
• Hall chopper stabilization technique for precise signal response over operating range
• Antistall feature guarantees continuous rotation and prevents overheating
• Single-chip solution for high reliability
• Miniature MLP/DFN package with industry-leading 0.40 mm maximum overall thickness

Description

The A1448 is a full-bridge motor driver designed to drive low-voltage, brushless DC motors. The A1448 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. A1448 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. A1448 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. A1448 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 A1448 ideally suited for use in applications where printed circuit board area and component headroom are at a premium. A1448 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.