POWER AND LINEAR IC SOLUTIONS

Low Quiescent Current 2A Buck Regulator

Automotive electronics environments can be electrically very caustic to power ICs, requiring designers to develop more innovative and electrically rugged designs. Often devices will need to operate through both cold crank and load dump scenarios, while keeping the output voltage within regulation to protect downstream electronics.

In addition, with the increasing need for always-on systems, such as security, navigation and environmental control, many of these power ICs must operate in standby with minimal quiescent current (<100µA) so as not to drain the car battery.

The LT3980 from Linear Technology is a 2A step-down switching regulator with Burst Mode operation to maintain quiescent current under 85µA. In a typical automotive application requiring a 3.3V output, the device can operate within a V_in range of 4.3V to 58V, with overvoltage lockout protection against transients of up to 80V.

The combination of a 3mm x 4mm DFN-16 package (or thermally enhanced MSOP-16E) and high switching frequency keeps the LT3980’s external inductor and additional capacitors small, providing a compact, thermally efficient footprint. The device’s internal 3.4A switch can deliver up to 2A of continuous output current at voltages as low as 0.79V. It offers efficiencies as high as 87% while stepping down a 12V input to a 3.3V output. The switching frequency is user programmable from 100kHz to 2.4MHz, enabling the designer to maximise efficiency while avoiding critical noise-sensitive frequency bands.


All the necessary boost diode, oscillator, control and logic circuitry for the LT3980 are integrated on to the chip. Its catch diode current sense protects the circuit during input voltage transients even at high switching frequencies. Other features include external synchronisation (from 250kHz to 2MHz), a power good flag and soft-start capability.



Features

• Wide input voltage range: 3.6V to 58V
• Overvoltage lockout protects against 80V transients
• 2A maximum output current
• Low ripple: <15mV peak-peak
• Adjustable switching frequency: 100kHz to 2.4MHz
• Low shutdown current: <1µA
• Can synchronise between 250kHz and 2MHz
• Compact 16-pin thermally enhanced MSOP or 3mm × 4mm DFN package formats

Applications

• Automotive electronic control units
• In-vehicle security systems
• Automotive navigation systems
• Cabin environmental control systems

For further information, to register your interest in a Free Demo Board*, or to obtain a copy of the latest Altera/LTC Development Tools Brochure or the new Linear Technology Product Guide, please click here

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