Features • 1.3V to 3.5V 5-bit programmable output voltage • Synchronous rectification • Power Good flag and output enable • Over-voltage protection • Initial Output Accuracy: 1.5% over temperature • Current limit without external sense resistor • Adaptive non-overlapping MOSFET gate drives • Adjustable switching frequency: 50 kHz to 1 MHz • Dynamic output voltage positioning • 1.256V reference voltage available externally • Plastic SO-20 package and TSSOP-20 package Description The LM2636 is a high speed controller designed specifically for use in synchronous DC/DC buck converters for advance d microprocessors. A 5-bit DAC accepts the VID code directly from the CPU and adjusts the output voltage from 1.3V to 3.5V. It provides the power good, over-voltage protection, and output enable features as required by Intel VRM specifications. Current limiting is achieved by monitoring the voltage drop across the rDS_ON of the high side MOSFET, which eliminates an expensive current sense resistor. The LM2636 employs a fixed-frequency voltage mode PWM architecture. To provide a faster response to a large and fast load transient, two ultra-fast comparators are built in to monitor the output voltage and override the primary control loop when necessary. The PWM frequency is adjustable from 50 kHz to 1 MHz through an external resistor. The wide range of PWM frequency gives the power supply designer the flexibility to make trade-offs between load transient response performance, 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 that no spurious turn-on occur. When only 5V is available, a bootstrap structure can be employed to accommodate an NMOS high side switch. The precision reference trimmed to 2.5% over temperature is available externally for use by other regulators. Dynamic positioning of load voltage, which helps cut the number of output capacitors, can also be implemented easily. Applications • Motherboard power supply/VRM for Cyrix Gxm, Cyrix Gxi, Cyrix MII, Pentium™ II, Pentium Pro, 6x86 and K6 processors • 5V to 1.3V-3.5V high current power supplies

Also Recommended LM2727▲ Single Channel, Vout Down To 0.6V LM2633▲ Dual Controller, One Sub-Bangap Output Channel MY BRIEFCASE                                       Click any "Briefcase" icon to add an item

Typical Application click for larger image	Block Diagram click for larger image

Datasheet

Title		Size	Date	Other Language
	LM2636 5-Bit Programmable Synchronous Buck Regulator Controller	766 Kbytes	25-Mar-05

Featured Application Notes

Title		Size	Date	Other Language
	AN-1146: Application Note 1146 Designing a Multi-phase Asynchronous Buck Regulator Using the LM2639	127 Kbytes	10-May-04

More Application Notes

Title		Size	Date	Other Language
	AN-1208: Application Note 1208 LM2633 Evaluation Board	700 Kbytes	10-May-04

Part Number(s) (NSID)	Top View	Availability	Current Reported Stock	Budgetary Pricing	Standard Pack Size
LM2636M/NOPB LM2636M RoHS	SOIC WIDE	Lifetime buy Lead Time: 16 weeks	Distributor Region Qty DIGIKEY Worldwide 208 FUTURE Worldwide 252	$1.60 each at 1K+ pcs	rail of 36
LM2636MX/NOPB LM2636MX RoHS	SOIC WIDE	Lifetime buy Lead Time: 16 weeks	Distributor Region Qty DIGIKEY Worldwide 0	$1.60 each at 1K+ pcs	reel of 1000
LM2636MTC/NOPB RoHS	TSSOP	Lifetime buy Lead Time: 6 weeks	Distributor Region Qty BRITESTONE South Korea 2 DIGIKEY Worldwide 174 TAYLOR Americas 204	$1.60 each at 1K+ pcs	rail of 73
LM2636MTCX/NOPB LM2636MTCX RoHS	TSSOP	Lifetime buy Lead Time: 6 weeks	Distributor Region Qty DIGIKEY Worldwide 0	$1.60 each at 1K+ pcs	reel of 2500

Obsolete Versions

Obsolete Part	Alternate Part or Supplier	Source	Last Time Buy Date
LM2636M	NONE	NONE	30 Nov 2009
LM2636MTC	NONE	NONE	30 Nov 2009
LM2636MTCX	NONE	NONE	30 Nov 2009
LM2636MX	NONE	NONE	30 Nov 2009

Reliability Metrics

Part Number	Process	EFR Reject	EFR Sample Size	PPM	LTA Rejects	LTA Device Hours	FITS	MTTF (Hours)
LM2636M	ABCD150	0	34175	0	0	4234000	1	1201409060
LM2636MTC	ABCD150	0	34175	0	0	4234000	1	1201409060
LM2636MTCX	ABCD150	0	34175	0	0	4234000	1	1201409060
LM2636MX	ABCD150	0	34175	0	0	4234000	1	1201409060

Note: The Early Failure Rates (EFR) were calculated as point estimate PPM based on rejects and sample size for EFR. The Long Term Failure Rates were calculated at 60% confidence using the Arrhenius equation at 0.7eV activation energy and derating the assumed stress temperature of 150°C to an application temperature of 55°C.

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Obsolete Versions

Obsolete Part	Alternate Part or Supplier	Source	Last Time Buy Date
LM2636M	NONE	NONE	30 Nov 2009
LM2636MTC	NONE	NONE	30 Nov 2009
LM2636MTCX	NONE	NONE	30 Nov 2009
LM2636MX	NONE	NONE	30 Nov 2009