1A Synchronous Buck Regulators with Integrated Power Devices

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Semtech's SC194 series sets the bar for high efficiency and low quiescent current operation, providing a flexible 1A synchronous buck regulator solution capable of dynamic voltage positioning without using external resistors.

The SC194 product series features highly integrated 1A DC-to-DC stepdown (buck) regulators with the small size and output flexibility needed for a wide variety of applications.

The SC194 has an input voltage range from 2.7V to 5.5V with a focus on lower power applications which use single cell Li-ion or three NiCd/NiMH/alkaline batteries. The device uses two programming pins to allow users to set the output voltage. The SC194A variant programs to 1.0V, 1.2V, 1.5V or 1.8V, while the SC194B variant accommodates fixed 2.5V, 3.0V, 3.3V or 3.6V values. 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 control.

Integrated switching Field Effect Transistors (FETs) eliminate the need for an external Schottky diode. Complete power regulation is achieved using only the SC194 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 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 SC194 is designed for high efficiency at all loads to maximize battery life. For example, the SC194A 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 17µA. PSAVE mode operation is monitored such that the device automatically detects when to disable this operation or can be manually taken out of PSAVE mode by toggling a single control pin. This is useful in controlling the electrical noise floor created by a switching regulator topology.

The SC194 has built-in soft start, short circuit, over voltage and over temperature protection features. Furthermore, fast transient reaction protects sensitive loads from extensive supply voltage variations.

 

 

Features Up to 93% efficiency (1.8V out) over wide load range Power Save operation to maximize efficiency 1A output current Wide input voltage range: 2.7V to 5.5V Selectable output voltages SC194A – 1.0V, 1.2V, 1.5V or 1.8V SC194B - 2.5V, 3.0V, 3.3V or 3.6V 17µA quiescent current 100% duty cycle operation Fixed 1MHz frequency or synchronizable between 750kHz to 1.25MHz Tight load regulation across all power, load and temperature conditions Available in lead-free and RoHS-compliant, 3mm x 3mm MLP-10 package Minimal external components Fast transient response 100% duty cycle in dropout Soft start Over temperature and short circuit protection

Applications SC194A Cell phones PDAs and mobile communicators Wireless communication chipset power SC194B PDAs Pocket PCs and Smart Phones USB powered modems

 

 

 Featured Products

Part Number		Description	Data Sheet	App. Notes
SC194AMLTRT		1A Synchronous Buck Converter with Integrated Power Devices
SC194BEVB		Evaluation Board
SC194BMLTRT		1A Synchronous Buck Converter
SC194EVB		Evaluation Board

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