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SC194B Dataheets PDF



Part Number SC194B
Manufacturers Semtech
Logo Semtech
Description Selectable 3.6V/3.3V/3.0V/2.5V 1A Synchronous Buck Converter
Datasheet SC194B DatasheetSC194B Datasheet (PDF)

Selectable 3.6V/3.3V/3.0V/2.5V www.DataSheet4U.com 1A Synchronous Buck Converter POWER MANAGEMENT Description The SC194B is a synchronous step-down converter with integrated power devices. Four selectable output voltages suitable for portable device interface, memory function blocks, and 5V to 3.3V voltage conversion are available. Automatic selection of Power Save Mode (PSAVE) is supported which enhances efficiency. A 100% duty cycle mode allows operation for input voltages close to the required.

  SC194B   SC194B



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Selectable 3.6V/3.3V/3.0V/2.5V www.DataSheet4U.com 1A Synchronous Buck Converter POWER MANAGEMENT Description The SC194B is a synchronous step-down converter with integrated power devices. Four selectable output voltages suitable for portable device interface, memory function blocks, and 5V to 3.3V voltage conversion are available. Automatic selection of Power Save Mode (PSAVE) is supported which enhances efficiency. A 100% duty cycle mode allows operation for input voltages close to the required output voltage. The need for external components is minimized by providing internal feedback compensation, and allowing selection of the required output voltage by hard wiring VID code inputs. The maximum current rating of the internal MOSFET switches allows a DC output current of 1A. The switching frequency is nominally set to 1MHz, allowing the use of small inductors and capacitors. A flexible clocking scheme is used that allows synchronization to an external oscillator or control by the internal oscillator. The device can operate in either forced PWM mode or in PSAVE mode. If PSAVE mode is enabled the part will automatically enter PSAVE at light loads to maintain maximum efficiency across the full load range. For noise sensitive applications, PSAVE mode can be disabled by synchronizing to an external oscillator, or pulling the SYNC/ PWM pin high. Shutdown turns off all the control circuitry to achieve a typical shutdown current of 0.1μA. SC194B Features ‹ ‹ ‹ ‹ ‹ ‹ ‹ ‹ ‹ ‹ ‹ ‹ ‹ Up to 95% efficiency PSAVE operation to maximize efficiency Output current — 1A Input range — 2.7V to 5.5V Four selectable output voltages Quiescent current — 17μA in PSAVE Dynamic voltage positioning capability Fixed 1MHz frequency or 750kHz to 1.25MHz synchronized operation Current mode operation for excellent line and load transient response 100% duty cycle in dropout Soft-start Over-temperature and short-circuit protection Lead-free package — 3mm x 3mm MLPD Applications ‹ ‹ ‹ ‹ ‹ ‹ ‹ PDA Pocket PC and Smart Phones USB Powered Modems CPUs and DSPs PC Cards and Notebooks xDSL Applications Standard 5-V to 3.3-V Conversion Typical Application Circuit SC194B VIN 3.6V to 5.5V CIN 10μF VIN EN SYNC/PWM VID0 VID1 MODE LX VOUT PGND GND L1 4.7μH COUT 22μF VOUT 3.3V 1A August 24, 2006 1 www.semtech.com SC194B POWER MANAGEMENT Absolute Maximum Ratings Parameter Input Supply Voltage Logic Inputs (SYNC/PWM, EN, MODE, VID0, VID1) Output Voltage LX Voltage Thermal Impedance Junction to Ambient(1) VOUT Short-Circuit to GND Operating Ambient Temperature Range Storage Temperature Junction Temperature Peak IR Reflow Temperature ESD Protection Level (2) Symbol VIN VN VOUT VLX θJA tSC TA TS TJC TP VESD Maximum -0.3 to 7 -0.3 to VIN +0.3, 7V Max -0.3 to VIN +0.3, 7V Max -1 to VIN +1, 7V Max 40 Continuous -40 to +85 -60 to +160 -40 to +150 260 2 www.DataSheet4U.com Exceeding the specifications below may result in permanent damage to the device or device malfunction. Operation outside of the parameters specified in the Electrical Characteristics section is not recommended. Units V V V V °C/W s °C °C °C °C kV Note: (1) Calculated from package in still air, mounted to 3” x 4.5”, 4 layer FR4 PCB with thermal vias under the exposed pad per JESD51 standards. (2) Tested according to JEDEC standard JESD22-A114-B. Electrical Characteristics Unless otherwise noted: VIN = 5V ,VOUT = 3.3V, EN = VIN, SYNC/PWM = VIN, MODE = VIN , TA = -40 to 85°C. Typical values are at TA =25°C. Parameter Input Voltage Range VOUT Accuracy VOUT Temperature Accuracy Line Regulation Load Regulation (PWM) PSAVE Regulation P-Channel On Resistance N-Channel On Resistance Start-Up Time P-Channel Current Limit © 2006 Semtech Corp. Symbol VIN VOUT VOUT(T) VOUT LINE VOUT LOAD VOUT PSAVE RDSP RDSN TSTART ILIM(P) Conditions VIN > VOUT + dropout IOUT = 0.5A, TA = 25°C VOUT = 2.5/3.0/3.3/3.6V IOUT = 0.5A, TA=-40°C to 85°C VIN = 2.7V to 5.5V, VOUT = 2.5V, IOUT = 0.5A, TA=-40°C to 85°C IOUT = 0A to 1A SYNC/PWM = GND, COUT=22μF ILX = 100mA, VIN=3.6V ILX = 100mA, VIN=3.6V Min 2.7 Typ Max 5.5 ±1 Units V % % % % % Ω Ω ±0.3 ±0.4 ±0.3 +1.3 -0.3 0.275 0.165 ±0.7 ±0.65 ±0.65 +1.6 -0.6 5 VIN = 2.7V to 5.5V 2 ms A 1.33 1.9 2.47 www.semtech.com SC194B POWER MANAGEMENT Electrical Characteristics (Cont.) Parameter Quiescent Current Shutdown Current LX Leakage Current PMOS LX Leakage Current NMOS Oscillator Frequency SYNC Frequency (upper) SYNC Frequency (lower) UVLO Threshold (upper) UVLO Hysteresis Thermal Shutdown Thermal Shutdown Hysteresis Logic Input High Logic Input Low Logic Input Current High Logic Input Current Low Symbol IQ ISD ILXP ILXN fOSC fSYNCU fSYNCL VUVL VUVLHYS TSD TSD-HYS VIH VIL IIH IIL EN, SYNC/PWM, VID0, VID1, MODE EN, SYNC/PWM, VID0, VID1, MODE EN, SYNC/PWM, VID0, VID1, MODE EN, SYNC/PWM, VID0, VID1, MODE -2 -2 0.1 0.1 1.6 0.6 2 2 Conditions SYNC/PWM = GND, IOUT = 0A, VOUT = 1.04 x VOUT(Programmed), VIN= 3.6V EN = GND, LX = OPEN, VIN= 3.6V VIN = 3.6V, LX = GND, EN = GND V.


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