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1.5A Buck Converter Provides High Efficiency, Simplicity and Convenience

9th June 2007

ES Admin

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Semtech has announced the SC196 and SC196A, two new 1.5A DC-DC step-down (buck) regulators. Both devices feature high efficiency due to low quiescent current and power save modes to target the lower voltage levels needed for next-generation portable device designs. The SC196 uses external feedback to allow the output voltage to be set anywhere between 1.0V and the input voltage for ultimate design flexibility. The SC196A uses two programming pins to set the output voltage to 1.0V, 1.05V, 1.2V or 1.8V. The voltage control pins can be hard-wired for a constant voltage, or they can be tied to a microcontroller and dynamically switched for applications that use digital power control such as microcontrollers that have lower sleep-state supply voltages. The input voltage ranges of 2.5V to 5.5V for SC196, and 2.7V to 5.5V for SC196A enable the use of many standard voltage rails, including Li-Ion batteries, as a supply for these devices.

The highly integrated SC196 devices include an internal compensation network and integrated switching and synchronous MOSFETs that eliminate the need for an external Schottky diode. Complete power regulation is achieved using only the SC196A and three discrete components, giving the user four output voltage options with a minimal bill of materials. The SC196 requires two extra resistors to program the output voltages.

“With the addition of the SC196 devices, Semtech has expanded its popular integrated buck converter family to support heavier loads,” said Karl Volk, Director of Marketing for Semtech’s Handheld Power Management Products Group. “All of our digitally programmable parts (SC194A, SC194B, SC196A) are pin-compatible with each other for easy design propagation, simplified stocking and sourcing. The external feedback of the SC196 allows the user to generate voltages not provided by the other devices.”

The flexible clocking scheme of the devices allows the designer to utilize an internal 1MHz fixed clock or connect the device to an external oscillator between 750kHz and 1.25MHz for applications requiring a different frequency or clock synchronization.

The SC196 devices are designed for high efficiency at all loads to maximize the battery life. The devices feature up to 95% maximum efficiency at 3.3V output. An industry-impressive quiescent current of only 17µA, combined with a user-selectable power save mode (PSAVE), allow the device to automatically enter pulse frequency modulation (PFM) at light loads and maintain very high device efficiency. The PSAVE operation can also be disabled for situations where the load is sensitive to noise.

The SC196 devices have built-in soft-start, short-circuit, over-voltage and over-temperature protection features. Furthermore, fast transient response protects sensitive loads from extreme supply voltage variations. The SC196 devices come in a 3mm x 3mm lead-free and RoHS compliant MLP-10 package.