Power Electronics

Buck Regulator Supports Digital Power Mangement

Semtech’s SC194A is a highly integrated 1-A dc-dc step-down (buck) regulator for portable applications. The device uses two programming pins to allow users to set the output voltage to 1.0 V, 1.2 V, 1.5 V or 1.8 V. These pins can be hard-wired to set a constant voltage, or they can be tied to a microcontroller and dynamically switched for applications that use digital power management.

The IC has an input voltage range from 2.7 V to 5.5 V with a focus on portable applications that use Li-ion batteries. It also includes an internal compensation network, integrated switching Field Effect Transistors (FETs) and eliminates the need for an external Schottky diode. Complete power regulation is achieved using only the SC194A and three discrete components, giving the user four output voltage options with a minimal bill of materials.

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

The SC194A is designed for high efficiency at all loads to maximize the battery life. The device features up to 93% maximum efficiency at 1.8V output over a broad range. An automatic power save mode (PSAVE) uses pulse frequency modulation (PFM) at light loads to maintain very high device efficiency. While in PSAVE mode, the device quiescent current is only 17 µA.

The SC194A comes in a 3-mm x 3-mm MLP-10 package. Available now, the device is priced at $1.42 each for 1000-unit quantities.

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