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.
Key Features
Applications/Uses
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
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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