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2 A Synchronous Step-Down DC/DC Converter Is 93% Efficient at 2 MHz

2 A Synchronous Step-Down DC/DC Converter Is 93% Efficient at 2 MHz

The LT8609 from Linear Technology Corp. is a 2 A , 42 V input synchronous step-down switching regulator. A unique synchronous rectification topology delivers 93% efficiency while switching at 2 MHz enabling designers to avoid critical noise-sensitive frequency bands, such as AM radio, while providing a highly compact solution footprint. Burst Mode® operation keeps quiescent current under 2.5 µA in no-load standby conditions, making it ideal for always-on systems. The LT8609's 3.0 V to 42 V input voltage range makes it ideal for automotive applications which must regulate through cold-crank and stop-start scenarios with minimum input voltages as low as 3.0 V and load dump transients in excess of 40 V. Its internal 3.5 A switches can deliver up to 2 A of continuous output current with peak load currents of 3 A.

The LT8609 maintains a minimum dropout voltage of only 200 mV (at 1 A) under all conditions, enabling it to excel in scenarios such as automotive cold-crank. Spread spectrum frequency modulation and special design techniques offer low-EMI operation to minimize noise concerns in automotive and industrial environments. Furthermore, a fast minimum on-time of only 45 ns enables 2 MHz constant frequency switching from a 16 V input to a 1.5 V output. The LT8609's 10-lead thermally enhanced MSOP package and high switching frequency keeps external inductors and capacitors small, providing a compact, thermally efficient footprint. The LT8609 utilizes 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. Other features include internal compensation, a power good flag, output soft start/tracking and thermal protection.

The LT8609EMSE is packaged in thermally enhanced MSOP-10 package and is priced at $2.50 each. An industrial temperature version, the LT8609IMSE, is tested and guaranteed to operate from a -40 °C to 125 °C operating junction temperature and is priced at $2.75. All pricing is for 1,000 piece quantities and all versions are available from stock.


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