Step-down controller runs 100% duty cycle

Dual-output step-down switching regulator DC/DC controller produces output voltages up to 30V.

The LT3742 from Linear Technology is a 100%-duty-cycle dual-output step-down switching regulator DC/DC controller that produces output voltages up to 30V for applications including stepper motors, industrial controls, automotive, distributed power and telecomms systems.

The LT3742 can also be configured with one side as a step-down voltage regulator and the other a supercapacitor charger (current source) for capacitor values up to several farads - a useful feature in robotic applications when longer hold-up times are needed or where high peak currents are required.

The LT3742's 100% duty cycle allows the output voltage to be very close to the input voltage, making it ideal for battery-powered systems.

The 4 to 30V input voltage range enables operation from a number of intermediate bus voltages.

A simple step-up DC/DC convertor is incorporated to generate its own gate drive voltage and also eliminates the extra parts required to drive the high-side MOSFETs.

The onboard gate driver powers a single external N-channel MOSFET for each output, enabling output currents up to 5A.

A constant 500kHz operating frequency with current mode control provides fast transient response and easy compensation.

Output current sensing is precisely measured by monitoring the voltage drop across a sense resistor and protects the convertor during overload and short circuit conditions.

In addition, the LT3742 has adjustable soft-start to control the output voltage ramp time and a power-good signal for each output.

The LT3742 is offered in a 4 x 4mm QFN-24 package.

Pricing for 1000-piece quantities begins at US $2.30 each.

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