LTC3788/-1 N-channel Mosfet replaces boost diode

Linear Technology has released the LTC3788/-1, a dual output, high-power synchronous step-up switching DC/DC controller that replaces the boost diode with a high efficiency N-channel Mosfet.

This eliminates the heat sink normally required in medium- to high-power boost converters.

The LTC3788/-1 can produce 24V at 5A output with up to 97 per cent efficiency, making it ideal for high-power automotive audio amplifiers, industrial and medical applications where a step-up DC/DC converter must deliver high power with low heat dissipation in a small solution size.

The LTC3788/-1 operates from an input voltage ranging from 4.5 to 38V during start-up, maintains operation down to 2.5V after start-up and can regulate an output voltage as high as 60V.

The powerful 1.5Ohm onboard N-channel Mosfet gate drivers are capable of slewing large Mosfet gates quickly, minimising transition losses and allowing for up to a 10A per channel output current.

In addition, the LTC3788/-1 draws only 125uA when one output is active and only 200uA when both outputs are enabled.

The constant frequency current-mode architecture allows for paralleled outputs.

The LTC3788 includes a clock output, phase modulation (for multiphase applications), two separate power good outputs and an adjustable current limit.

The LTC3788/-1 has a phase-lockable frequency from 75 to 850kHz or a selectable fixed frequency from 50 to 900kHz.

It has adjustable cycle-by-cycle current-limit protection and uses either a sense resistor or monitors the voltage drop across the inductor (DCR) for current sensing.

In applications where the input voltage may sometimes exceed the regulated output voltage, the LTC3788/-1 can keep the synchronous Mosfet on continuously so that the output voltage follows the input voltage with minimal power loss.

Furthermore, the LTC3788/-1 has adjustable soft-start and maintains +/- one per cent reference voltage accuracy over an operating temperature range of -40C to +125C.

The LTC3788-1 is available in an SSOP-28 package and the LTC3788 is housed in a 32-lead 5 x 5mm QFN.

The 1,000-piece price starts at USD4.12 (GBP2.70) each.

Both versions are available from stock.

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