LM2635 ,Synchronous Buck Regulator ControllerPin Descriptionsabled when this pin is pulled low. It is internally pulled up toV via a 90 μA curre ..
LM2635M ,5-Bit Programmable Synchronous Buck Regulator Controller [Not recommended for new designs]Pin Descriptionsabled when this pin is pulled low. It is internally pulled up toV via a 90 μA curre ..
LM2635MX ,5-Bit Programmable Synchronous Buck Regulator Controller [Not recommended for new designs]LM2635 5-Bit Programmable Synchronous Buck Regulator ControllerMay 2000LM2635 5-Bit ProgrammableSyn ..
LM2636 ,5-Bit Programmable Synchronous Buck Regulator ControllerApplicationsany potential shoot-through problem while maintaining highn Motherboard power supply/VR ..
LM2636M ,5-Bit Programmable Synchronous Buck Regulator ControllerGeneral Descriptionother regulators. Dynamic positioning of load voltage, whichThe LM2636 is a high ..
LM2636MTC ,5-Bit Programmable Synchronous Buck Regulator ControllerPin DescriptionsHSGATE (Pin 20): Gate drive for the high-side N-channelLSGATE (Pin 1): Gate drive f ..
LM4900MMX ,265mW at 3.3V Supply Audio Power Amplifier with Shutdown Modefeatures an externally controlled, low powern Thermal shutdown protection circuitryconsumptionshutd ..
LM4900MX ,265mW at 3.3V Supply Audio Power Amplifier with Shutdown ModeLM4900 265mW at 3.3V Supply Audio Power Amplifier with Shutdown ModeSeptember 2001LM4900265mW at 3. ..
LM4901LD ,1.6 Watt Audio Power Amplifier with Selectable Shutdown Logic LevelElectrical Characteristics V =5V (Notes 1, 2)DDThe following specifications apply for the circuit s ..
LM4901MM ,1.6 Watt Audio Power Amplifier with Selectable Shutdown Logic Levelfeatures a low-power consumption shutdownn Improved pop & click circuitry eliminates noise duringmo ..
LM4901MMX ,1.6 Watt Audio Power Amplifier with Selectable Shutdown Logic Levelapplications. It is capable ofj Power Output at 5.0V, 1% THD, 8Ω 1.07W (typ)delivering 1 watt of co ..
LM4902LD ,265mW at 3.3V Supply Audio Power Amplifier with Shutdown ModeApplicationsKey Specificationsn Cellular phonesj n PDA’sTHD+N at 1kHz for 265mW continuousn Any por ..
LM2635
Synchronous Buck Regulator Controller
LM2635 5-Bit Programmable
Synchronous Buck Regulator Controller
General DescriptionThe LM2635isa high speed controller designed specifically
for usein synchronous DC/DC buck converters for the
Pentium™IIor Deschutes microprocessor.A 5-bit DAC ac-
cepts the VID code directly from the CPU and adjusts the
output voltage from 1.8Vto 3.5V.It providesthe power good,
over-voltage protection, and output enable featuresasre-
quired by Intel VRM specifications. Current limitingis
achievedby monitoring the voltage drop acrossthe rDS_ON the high side MOSFET, which eliminatesan expensive
current sense resistor.
The LM2635 employsa fixed-frequency voltage mode PWM
architecture.To providea faster responsetoa large and fast
load transient, two ultra-fast comparatorsare builtinto moni-
torthe output voltage and override the primary control loop
when necessary. The PWM frequencyis adjustable from50
kHzto1 MHz throughan external resistor. The wide rangeof
PWM frequency givesthe power supply designerthe flexibil-
ityto make trade-offs between load transient response per-
formance, MOSFET cost and the overall efficiency. The
adaptive non-overlapping MOSFET gate drivers help avoid
any potential shoot-through problem while maintaining high
efficiency. BiCMOS gate drivers with rail-to-rail swing ensure
thatno spurious turn-on occur. When only5Vis available,a
bootstrap structure canbe employedto accommodatean
NMOS high side switch. The precision reference trimmedto over temperatureis available externallyfor useby other
regulators. Dynamic positioningof load voltage, which helps
cut the numberof output capacitors, can alsobe imple-
mented easily.
Features 1.8Vto 3.5V 5-bit programmable output voltage Synchronous rectification Power Good flag and output enable Over-voltage protection Initial Output Accuracy: 2% over temperature Current limit without external sense resistor Adaptive non-overlapping MOSFET gate drives Adjustable switching frequency:50 kHzto1 MHz Dynamic output voltage positioning 1.256V reference voltage available externally Plastic SO-20 package
Applications Motherboard power supply/VRMfor Cyrix Gxm, Cyrix
Gxi, Cyrix MII, PentiumII, Deschutes, Pentium Pro,
6x86 andK6 processors5Vto 1.8V–3.5V high current power supplies
Typical ApplicationDS100119-1
FIGURE1.5Vto 1.8V–3.5V, 14A Power SupplyMay 2000
LM2635
5-Bit
Programmable
Synchronous
Buck
Regulator
Controller
