Datasheet
RoHS Compliance Information
| Size in Kbytes | Date |
 |
| LM2638 Motherboard Power Supply Solution with a 5-Bit Programmable Switching Controller and Two Linear Regulator Controllers |
165
Kbytes |
26-Jun-99 |
Download |
LM2638 Motherboard Power Supply Solution with a 5-Bit Programmable Switching Controller and Two Linear Regulator Controllers (Japanese)
 |
116 Kbytes |
|
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Package Availability, Models, Samples & Pricing
| Obsolete Part | Alternate Part or
Supplier | Source | Last Time Buy Date |
LM2638M
| NONE
| NATIONAL SEMICONDUCTOR
| 01 Dec 2009
|
General Description
The LM2638 provides a comprehensive embedded power supply solution for motherboards hosting high performance MPUs such as Pentium™ II, M II™, K6™-2 and other similar high performance MPUs. The LM2638 incorporates a 5-bit programmable, synchronous buck switching controller and two high-speed linear regulator controllers in a 24-pin SO package. In a typical application, the switching controller supplies the MPU core, and the linear regulator controllers supply the GTL+ bus and the clock or graphics chip core. A charge pump pin helps provide the necessary voltage to power the linear sections when 12V is shut off during system standby such as STR mode.
Switching Section - The switching regulator controller features an Intel-compatible, 5-bit programmable output voltage, over-current and over-voltage protection, a power good signal, and a logic-controlled output enable. There are two user-selectable over-current protection methods. One provides accurate over-current protection with the use of an external sense resistor. The other saves cost by taking advantage of the rDS[lowbar]ON of the high-side FET. When there is an over voltage, the controller turns off the high side FET and turns on the low side.
Linear Section - The two linear regulator controllers feature wide control bandwidth, N-FET and NPN transistor driving capability and an adjustable output. The wide control bandwidth makes meeting the GTL+ bus transient response requirement an easy job. In minimum configuration, the two controllers default to 1.5V and 1.25V respectively.
Both linear controllers have under voltage latch-off.
Reliability Metrics
| Part Number |
Process |
EFR Reject |
EFR Sample Size |
PPM |
LTA Rejects |
LTA Device Hours |
FITS |
MTTF (Hours) |
|
LM2638M | 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.
For more information on Reliability Metrics, please click here.
More Application Notes
| Title | Size in Kbytes |
Date |
|
| AN-1146: Application Note 1146 Designing a Multi-phase Asynchronous Buck Regulator Using the LM2639 |
127
Kbytes |
10-May-04 |
Download |
| AN-1208: Application Note 1208 LM2633 Evaluation Board |
700
Kbytes |
10-May-04 |
Download |
[Information as of 8-Nov-2009]
|
