3.5A output, 2.2-MHz automotive step-down DC/DC with 2.5µA Iq

October 30, 2014 // By Graham Prophet
LT8610AC is a 3.5A, 42V input capable synchronous step-down switching regulator. Synchronous rectification delivers efficiency of up to 96%, while Burst Mode operation keeps quiescent current under 2.5 µA in no-load standby conditions.

The device's 3.0V to 42V input voltage range suits it to automotive applications, which must regulate through cold-crank/stop-start scenarios with minimum input voltages as low as 3.0V and load dump transients in excess of 40V. Its internal 5A switches can deliver up to 3.5A of continuous output current to voltages as low as 0.80V.

Burst Mode operation offers very low quiescent current, for applications such as automotive “always-on” systems. The LT8610AC’s design maintains a minimum dropout voltage of only 200 mV at 1A under all conditions, including automotive cold-crank. A fast minimum on-time of 30 nsec enables 2 MHz constant frequency switching (synchronisable over 200 kHz to 2.2 MHz) from a 16V input to a 1.0V output. The 16-lead thermally enhanced MSOP package and high switching frequency keeps external inductors and capacitors small, providing a compact, thermally efficient footprint.

The LT8610AC has internal top and bottom high efficiency power switches with the necessary boost diode, oscillator, control and logic circuitry integrated into a single die. Low ripple Burst Mode operation maintains high efficiency at low output currents while keeping output ripple below 10 mVpk-pk: current-mode topology enables fast transient response and excellent loop stability. Other features include internal compensation, a power good flag, output soft-start/tracking and thermal protection.

The LT8610ACEMSE is packaged in thermally enhanced MSOP-16 package and is priced at $3.75. An industrial temperature version, the LT8610ACIMSE, is tested and guaranteed to operate from a -40°C to 125°C operating junction temperature and is priced at $4.13. An automotive temperature version, the LT8610ACHMSE, is tested and guaranteed to operate from a -40°C to 150°C operating junction temperature, priced at $4.38 (all 1000).

Linear Technology; www.linear.com/product/LT8610AC