LM2657MTC ,Dual Synchronous Buck Regulator ControllerPin Descriptionhigher than the steady-state requirement. This forms thePin1,SENSE1:Outputvoltagesen ..
LM2660M ,Switched Capacitor Voltage ConverterFeaturesn Inverts or doubles input supply voltageThe LM2660/LM2661 CMOS charge-pump voltage con-ver ..
LM2660M/NOPB ,Switched Capacitor Voltage Converter 8-SOIC -40 to 85Features 3 DescriptionThe LM2660 CMOS charge-pump voltage converter1• Inverts or Doubles Input Supp ..
LM2660MM ,Switched Capacitor Voltage ConverterElectrical CharacteristicsLimits in standard typeface are for T = 25˚C, and limits in boldface type ..
LM2660MM ,Switched Capacitor Voltage ConverterLM2660/LM2661 Switched Capacitor Voltage ConverterSeptember 1999LM2660/LM2661Switched Capacitor Vol ..
LM2660MM ,Switched Capacitor Voltage ConverterElectrical CharacteristicsLimits in standard typeface are for T = 25˚C, and limits in boldface type ..
LM4961LQX ,Ceramic Speaker DriverElectrical Characteristics V = 4.2VDDThe following specifications apply for V = 4.2V, A = 26dB, R = ..
LM4970SD ,Audio Synchronized Color LED DriverPin Description1 FILT Low Pass Filter Input2V Power Supply PinDD3M Mono Audio InputIN4 GND Ground5L ..
LM4970SDX ,Audio Synchronized Color LED DriverElectrical Characteristics V = 5.0V (Notes 1, 2, 9)DDThe following specifications apply for V = 5.0 ..
LM4981SQ , Ground-Referenced, 80mW Stereo Headphone Amplifier with Digital Volume Control
LM4990 ,2 Watt Audio Power Amplifier with Selectable Shutdown Logic LevelFeaturescations where minimal power consumption is a primary re-quirement. n Available in space-sav ..
LM4990 ,2 Watt Audio Power Amplifier with Selectable Shutdown Logic Levelfeatures a low-power consumption shutdownn Ultra low current shutdown modemode. To facilitate this, ..
LM2657MTC
Dual Synchronous Buck Regulator Controller
LM2657
Dual Synchronous Buck Regulator Controller
General DescriptionThe LM2657isan adjustable 200kHz-500kHz dual channel
voltage-mode controlled high-speed synchronous buck
regulator controller ideally suitedfor high current applica-
tions. The LM2657 requires only N-channel FETsfor both
the upper and lower positionsof each stage.It features line
feedforwardto improve the responseto input transients.At
very light loads, the user can choose between the high-
efficiency Pulse-skip modeor the constant frequency
Forced-PWM mode. Lossless current limiting withoutthe use external sense resistorsis made possibleby sensing the
voltage drop acrossthe bottom FET.A unique adaptive duty
cycle clamping techniqueis incorporatedto significantlyre-
duce peak currents under abnormal load conditions. The two
independently programmable outputs switch 180˚ outof
phase (interleaved switching) reducing the input capacitor
and filter requirements. The input voltage rangeis 4.5Vto
28V whilethe output voltages are adjustable downto 0.6V.
Standard supervisory and control features include Soft-start,
Power Good, output Under-voltage and Over-voltage protec-
tion, Under-voltage Lockout, and chip Enable.
Features Input voltage range from 4.5Vto 28V Synchronous dual-channel interleaved switching Forced-PWMor Pulse-skip modes Lossless bottom-side FET current sensing Adaptive duty cycle clamp High current N-channel FET drivers Low shutdown supply current Reference voltage accurateto within ±1.5% Output voltage adjustable downto 0.6V Power Good flag and Chip Enable Under-voltage lockout Over-voltage/Under-voltage protection Soft-start Switching frequency adjustable 200kHz-500kHz TSSOP-28 package
Applications Low Output Voltage High-Efficiency Buck Regulators
Typical Application (Channel2 in parenthesis)January 2005
LM2657
Dual
Synchronous
Buck
Regulator
Controller
