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Data Sheet

FULL DATA SHEET (PDF, 616kB) Download   E-Mail

Description

The MAX1845 is a dual PWM controller configured for step-down (buck) topologies that provides high efficiency, excellent transient response, and high DC output accuracy necessary for stepping down high-voltage batteries to generate low-voltage chipset and RAM power supplies in notebook computers. The CS_ inputs can be used with low-side sense resistors to provide accurate current limits or can be connected to LX_, using low-side MOSFETs as current-sense elements. The on-demand PWM controllers are free running, constant on-time with input feed-forward. This configuration provides ultra-fast transient response, wide input-output differential range, low supply current, and tight load-regulation characteristics. The MAX1845 is simple and easy to compensate. Single-stage buck conversion allows the MAX1845 to directly step down high-voltage batteries for the highest possible efficiency. Alternatively, two-stage conversion (stepping down the 5V system supply instead of the battery at a higher switching frequency) allows the minimum possible physical size. The MAX1845 is intended for generating chipset, DRAM, CPU I/O, or other low-voltage supplies down to 1V. For a single-output version, refer to the MAX1844 data sheet. The MAX1845 is available in 28-pin QSOP and 36-pin thin QFN packages.

Key Features		Applications/Uses
Ultra-High Efficiency Accurate Current-Limit Option Quick-PWM™ with 100ns Load-Step Response 1% VOUT Accuracy over Line and Load Dual Mode™ Fixed 1.8V/1.5V/Adj or 2.5V/Adj Outputs Adjustable 1V to 5.5V Output Range 2V to 28V Battery Input Range 200/300/420/540kHz Nominal Switching Frequency Adjustable Overvoltage Protection 1.7ms Digital Soft-Start Drives Large Synchronous-Rectifier FETs Power-Good Window Comparator 2V ±1% Reference Output		1.8V and 2.5V I/O Supplies Chipset/RAM Supplies as Low as 1V CPU Core Supplies Notebook Computers

Diagram

Minimal Operating Circuit

Application Notes

Application Note 1845: Choosing the Right DC-DC Converter for Automotive Applications - MAX1845

Evaluation Kits

MAX1845EVKIT

Design Guides

Low-Power Notebook ICs (PDF)

Reliability Reports

Show FIT data for: MAX1845 Reliability Report: MAX1845Exx.pdf AEC-Q100 Reliability Report MAX1845EEI.pdf

Software/Models

none

Ordering Information
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. More: SeeFull Data Sheet or Part 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.
Devices: 1-8 of 8
MAX1845	Free Sample	Buy	Package: TYPE PINS FOOTPRINT   DRAWING CODE/VAR *	Temp	RoHS/Lead-Free? Materials Analysis
MAX1845EEI			QSOP;28 pin; Dwg: 21-0055 (PDF) Use pkgcode/variation: E28-1*	-40°C to +85°C	RoHS/Lead-Free: No Materials Analysis
MAX1845EEI-T			QSOP;28 pin; Dwg: 21-0055 (PDF) Use pkgcode/variation: E28-1*	-40°C to +85°C	RoHS/Lead-Free: No Materials Analysis
MAX1845EEI+			QSOP;28 pin; Dwg: 21-0055 (PDF) Use pkgcode/variation: E28+1*	-40°C to +85°C	RoHS/Lead-Free: Lead Free Materials Analysis
MAX1845EEI+T			QSOP;28 pin; Dwg: 21-0055 (PDF) Use pkgcode/variation: E28+1*	-40°C to +85°C	RoHS/Lead-Free: Lead Free Materials Analysis
MAX1845ETX			THIN QFN;36 pin; Dwg: 21-0141 (PDF) Use pkgcode/variation: T3666-3*	-40°C to +85°C	RoHS/Lead-Free: No Materials Analysis
MAX1845ETX-T			THIN QFN;36 pin; Dwg: 21-0141 (PDF) Use pkgcode/variation: T3666-3*	-40°C to +85°C	RoHS/Lead-Free: No Materials Analysis
MAX1845ETX+			THIN QFN;36 pin; Dwg: 21-0141 (PDF) Use pkgcode/variation: T3666+3*	-40°C to +85°C	RoHS/Lead-Free: Lead Free Materials Analysis
MAX1845ETX+T			THIN QFN;36 pin; Dwg: 21-0141 (PDF) Use pkgcode/variation: T3666+3*	-40°C to +85°C	RoHS/Lead-Free: Lead Free Materials Analysis

More Information

New Product Press Release 2001-02-13

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