Features and Benefits
- Better than ±1% Output Accuracy Over Line and Load
- Greater than 90% Efficiency Using N-Channel MOSFETs
- Pin-Selected High Switching Frequency (300kHz, 600kHz, or 1MHz)
- Over 35A Output Current
- Digitally Programmable Output from 1.3V to 3.5V
- Current-Mode Control for Fast Transient Response and Cycle-by-Cycle Current-Limit Protection
- Short-Circuit Protection with Foldback Current Limiting
- Glitch-Catcher Circuit for Fast Load-Transient Response
- Crowbar Overvoltage Protection
- Power-Good (PWROK) Output
- Digital Soft-Start
- High-Current (2A) Drive Outputs
- Complies with Intel VRM 8.2 Specification
The MAX1638 is an ultra-high-performance, step-down DC-DC controller for CPU power in high-end computer systems. Designed for demanding applications in which output voltage precision and good transient response are critical for proper operation, it delivers over 35A from 1.3V to 3.5V with ±1% total accuracy from a +5V ±10% supply. Excellent dynamic response corrects output transients caused by the latest dynamically clocked CPUs. This controller achieves over 90% efficiency by using synchronous rectification. Flying-capacitor bootstrap circuitry drives inexpensive, external N-channel MOSFETs.
The switching frequency is pin-selectable for 300kHz, 600kHz, or 1MHz. High switching frequencies allow the use of a small surface-mount inductor and decrease output filter capacitor requirements, reducing board area and system cost.
The MAX1638 is available in 24-pin SSOP and QSOP (future package) packages, and offers additional features such as a digitally programmable output; adjustable transient response; and selectable 0.5%, 1%, or 2% AC load regulation. Fast recovery from load transients is ensured by a GlitchCatcher current-boost circuit that eliminates delays caused by the buck inductor. Output overvoltage protection is enforced by a crowbar circuit that turns on the low-side MOSFET with 100% duty factor when the output is 200mV above the normal regulation point. Other features include internal digital soft-start, a power-good output, and a 3.5V ±1% reference output.
- Computers: Desktop, Workstation, Server
- GTL Bus Termination
- LAN Servers
Product Lifecycle Production
At least one model within this product family is in production and available for purchase. The product is appropriate for new designs but newer alternatives may exist.
Evaluation Kits (1)
The MAX1638VRM evaluation kit (EV kit) provides a digitally programmable output voltage between 1.3V and 3.5V from a 5V input supply. It delivers up to 14A output current with greater than 90% efficiency. The MAX1638 features 1% output accuracy as well as 1% AC-load regulation. The EV kit operates at a 600kHz switching frequency and has excellent dynamic response to correct for fast output transients.
A separate test-fixture PC board emulates a system motherboard and contains a 22µF ceramic capacitor that models the local CPU bypass capacitors. The test fixture also puts the GlitchCatcher™ mosfets on the correct side of the VRM connector, in order to reduce stray inductance.
Features & Benefits
- 4.5V to 5.5V Input Voltage Range
- 1.3V to 3.5V Output Voltage Range
- 14A Output Current Capability
- 1% AC-Load Regulation
- Power-Good Output
- 600kHz Switching Frequency
- GlitchCatcher Provides Excellent Load-Transient Response (MAX1638VRM test fixture)
- 24-Pin SSOP Package
- Fully Assembled and Tested
Documentation & Resources
Power Supplies for Telecom Systems7/17/2002
MAX1638 Companion Parts
ADI has always placed the highest emphasis on delivering products that meet the maximum levels of quality and reliability. We achieve this by incorporating quality and reliability checks in every scope of product and process design, and in the manufacturing process as well. "Zero defects" for shipped products is always our goal.View our quality and reliability program and certifications for more information.
|Part Number||Material Declaration||Reliability Data||Pin/Package Drawing||CAD Symbols, Footprints & 3D Models|
|MAX1638EAG+||Material Declaration||Reliability Data||24-SSOP-5.3_MM|
|MAX1638EAG+T||Material Declaration||Reliability Data||24-SSOP-5.3_MM|
|Wafer Fabrication Data|
Sample & Buy
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