Low Side Driver with LDO Suits Compact Motor Control Systems



The Fairchild Semiconductor FAN3180 combines a 2A low side driver with an integrated 3.3V LDO regulator. Occupying a smaller footprint than the equivalent discrete design, the device helps designers realize the compact PCB designs required in space constrained motor control applications such as portable power tools.

The gate driver is rated for a 2.8A peak current when the supply voltage is 12V, and is designed to drive an N-channel enhancement-mode MOSFET in low-side switching applications. Supporting fast MOSFET switching, it incorporates the MillerDrive™ architecture for the final output driver stage. This bi-polar/MOSFET combination provides high peak current during the Miller plateau stage of the MOSFET turn-on/turn-off process to minimize switching loss, while providing rail-to-rail voltage swing and reverse-current capability.

The LDO can be used to power a host microcontroller or ASIC, in addition to providing a strong gate drive for an external semiconductor switch. It delivers output current of 15mA with tight voltage tolerance of ±1% at 25°C and ±2.5% of total variation.

The FAN3180 has a wide operating voltage range, from 5V to 18V, and has an input under-voltage lockout (UVLO) to ensure orderly start-up. As a combined low-side driver and LDO, it not only provides an economical and space saving solution for low power motor-control applications, but can also be used in general switched mode power conversion and consumer products.

• Portable power tools
• Switched mode power supplies (SMPS)
• Consumer electronics
• TTL compatible input thresholds
• Non-inverting logic configuration
• 200µA maximum stand-by current
• 23ns typical delay time
• 19ns/13ns rise/fall times with 1nF load
• Built-in thermal shutdown