Features GENERALSWITCHING SECTIONLINEAR SECTION • Three regulated output voltages • 4.5V to 30V input range • Power good function • Input under-voltage lockout • Thermal shutdown • Tiny TSSOP package • Two channels operating 180° out of phase • Separate on/off control for each channel • Current mode control without sense resistor • Skip-mode operation available • Adjustable cycle-by-cycle current limit • Negative current limit • Analog soft start independent of input voltage slew rate • Power ground pins separate • Output UVP and OVP • Programmable output UVP delay • 250kHz switching frequency (for Vin < 17V) • Channel 1 output from 0.925V to 2.00V • ±1.5% DAC accuracy from 0°C to 125°C • ±1.7% initial tolerance for Channel 2 • Dynamic VID change ready • Power good flags VID changes • Channel 2 output from 1.3V to 6.0V • Output voltage adjustable • 50mA maximum driving current • Output UVP • ±2% initial tolerance Description The LM2633 is a feature-rich IC that combines three regulator controllers - two current mode synchronous buck regulator controllers and a linear regulator controller. The two switching regulator controllers operate 180° out of phase. This feature reduces the input ripple RMS current, resulting in a smaller input filter. The first switching controller (Channel 1) features an Intel mobile CPU compatible precision 5-bit digital-to-analog converter which programs the output voltage from 0.925V to 2.00V. It is also compatible with the dynamic VID requirements. The second switching controller (Channel 2) is adjustable between 1.25V to 6.0V. Use of synchronous rectification and pulse-skip operation at light load achieves high efficiency over a wide load range. Fixed-frequency operation can be obtained by disabling the pulse-skip mode. Current-mode feedback control assures excellent line and load regulation and a wide loop bandwidth for good response to fast load transient events. Current mode control is achieved through sensing the Vds of the top FET and thus an external sense resistor is not necessary. A power good signal is available to indicate the general health of the output voltages. A unique feature is the analog soft-start for the switching controllers is independent of the slew rate of the input voltage. This will make the soft start behavior more predictable and controllable. An internal 5V rail is available externally for boot-strap circuitry (only) when no 5V is available from other sources. Current limit for either of the two switching channels is achieved through sensing the top FET VDS and the value is adjustable. The two switching controllers have under-voltage and over-voltage latch protections, and the linear regulator has under-voltage latch protection. Under-voltage latch can be disabled or delayed by a programmable amount of time. The input voltage for the switching channels ranges from 5V to 30V, which makes possible the choice of different battery chemistries and options. Applications • Power supply for CPUs of notebook PCs that require the SpeedStep™ technique • Power supply for information appliances • General low voltage DC/DC buck regulators

Also Recommended LM2647 Smaller Package And Pincount. Programmable Operating Frequency, Less Noise Sensitivity LM5642▲ Smaller Package And Pincount. Higher Operating Voltage And Synchronisable Clock MY BRIEFCASE                                       Click any "Briefcase" icon to add an item

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

Datasheet

Title		Size	Date	Other Language
	LM2633 Advanced Two-Phase Synchronous Triple Regulator Controller for Notebook CPUs	1898 Kbytes	18-Apr-05

Featured Application Notes

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

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	AN-1198: Application Note 1198 LM2622 Step-Up DC/DC Converter Evaluation Board	110 Kbytes	3-Apr-07

Obsolete Versions

Obsolete Part	Alternate Part or Supplier	Source	Last Time Buy Date
LM2633MTD	NONE	NATIONAL SEMICONDUCTOR	16 Nov 2008
LM2633MTDX	NONE	NATIONAL SEMICONDUCTOR	16 Nov 2008

Design Tools

Title	Size	Date
Article - Reducing Buck Converter Input Capacitance through Multi-Phasing and Clock Synchronization

Reliability Metrics

Part Number	Process	EFR Reject	EFR Sample Size	PPM	LTA Rejects	LTA Device Hours	FITS	MTTF (Hours)
LM2633MTD	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
LM2633MTD	NONE	NATIONAL SEMICONDUCTOR	16 Nov 2008
LM2633MTDX	NONE	NATIONAL SEMICONDUCTOR	16 Nov 2008