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MAX1638
High-Speed Step-Down Controller with Synchronous Rectification for CPU Power
Industry's Smallest, Fastest-Response Pentium® Pro / Pentium II Supply, Delivers >35A
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Status
Active: In Production.
Description
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.
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Data Sheet
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An evaluation kit is available: MAX1638EVKIT
Key Features
- 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
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Applications/Uses
- Computers: Desktop, Workstation, Server
- GTL Bus Termination
- LAN Servers
- Pentium®
- Workstations
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Key Specifications:
| Step-Down Switching Regulators |
| Part Number |
VIN
(V) |
VIN
(V) |
VOUT
(V) |
VOUT
(V) |
Max. IOUT
(A) |
Max. IOUT
(A) |
Output Adjust. Method |
DC-DC Outputs |
Oper. Freq.
(kHz) |
Package/Pins |
Smallest Available Pckg.
(mm2) |
Budgetary Price |
| min |
max |
min |
max |
≥ |
≤ |
max w/pins |
See Notes |
| MAX1638 |
4.5 |
5.5 |
1.3 |
5.5 |
35 |
35 |
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1 |
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65.8 |
$4.15 @1k |
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See All Step-Down Switching Regulators (284)
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Pricing Notes:
This pricing is BUDGETARY, for comparing similar parts. Prices are in U.S. dollars and subject to change. Quantity pricing may vary substantially and international prices may differ due to local duties, taxes, fees, and exchange rates. For volume-specific prices and delivery, please see the price and availability page or contact an authorized distributor.
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Diagram
 Typical Operating Circuit
Application Notes
Reliability Reports
| Show FIT data for: |
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| Request Reliability Report for: |
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Software/Models
Ordering Information
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Part Number
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Free
Sample |
Buy |
Status
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Package:
TYPE PINS FOOTPRINT
DRAWING CODE/VAR *
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Temp |
RoHS/Lead-Free?
Materials Analysis
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| MAX1638EAG
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Active |
SSOP;24 pin;65.8 mm²
Outline Drawing:21-0056 (PDF)
Land Pattern: 90-0110 (PDF)
Use pkgcode/variation: A24-2*
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-40°C to +85°C
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RoHS/Lead-Free: No
Materials Analysis |
| MAX1638EAG+
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Active |
SSOP;24 pin;65.8 mm²
Outline Drawing:21-0056 (PDF)
Land Pattern: 90-0110 (PDF)
Use pkgcode/variation: A24+2*
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-40°C to +85°C
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RoHS/Lead-Free: Lead Free
Materials Analysis |
| MAX1638EAG+T
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Active |
SSOP;24 pin;65.8 mm²
Outline Drawing:21-0056 (PDF)
Land Pattern: 90-0110 (PDF)
Use pkgcode/variation: A24+2*
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-40°C to +85°C
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RoHS/Lead-Free: Lead Free
Materials Analysis |
| MAX1638EAG-T
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Active |
SSOP;24 pin;65.8 mm²
Outline Drawing:21-0056 (PDF)
Land Pattern: 90-0110 (PDF)
Use pkgcode/variation: A24-2*
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-40°C to +85°C
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RoHS/Lead-Free: No
Materials Analysis |
Notes:
- Other options and links for purchasing parts are listed at: http://www.maxim-ic.com/sales.
- Didn't Find What You Need? Ask our applications engineers. Expert assistance in finding parts, usually within one business day.
- Part number suffixes: T or T&R = tape and reel; + = RoHS/lead-free; # = RoHS/lead-exempt; -D = drypack; -U/+U on DS parts = cut tape. More: See Full Data Sheet or Maxim Product Naming Conventions.
- * Some packages have variations, listed on the drawing. "PkgCode/Variation" tells which variation the product uses. Note that "+", "#", "-" in the part number suffix describes RoHS status. Package drawings may show a different suffix character.
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Notes and Comments
High accuracy Pentium Pro
VID programming, power-good output
Similar Products by Function
| MAX1624, MAX1625 |
High-Speed Step-Down Controllers with Synchronous Rectification for CPU Power |
| MAX1639 |
High-Speed Step-Down Controller with Synchronous Rectification for CPU Power |
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Evaluation Kits
Didn't Find What You Need?
Information Index
Document Ref.: 19-1313
Rev 1;
2005-09-26
This page last modified: 2007-10-31
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