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MAX747

High-Efficiency, PWM, Step-Down Controller (External P-Channel Driver)

Overview

Technical Documents

Ordering Info

Status

All versions are No Longer Available. See Ordering Information for recommended replacements.

Description

The MAX747 high-efficiency, high-current, step-down controller drives external P-channel FETs. It provides 90% to 95% efficiency from a 6V supply with load currents ranging from 50mA up to 2.5A. It uses a pulse-width-modulating (PWM) current-mode control scheme to provide precise output regulation and low output noise. The MAX747's 4V to 15V input voltage range, a fixed 5V/adjustable (Dual-Mode™) output, and a current limit set with an external resistor make this device ideal for a wide range of applications.

High efficiency is maintained with light loads due to a proprietary dual-control (Idle-Mode™) scheme that minimizes switching losses by reducing the switching frequency at light loads. The low 800µA quiescent current and ultra-low 0.6µA shutdown current further extend battery life.

External components are protected by the MAX747's cycle-by-cycle current limit. The MAX747 also features a 2V ±1.5% reference, a comparator for low-battery detection or level translating, as well as soft-start and shutdown capability.

The MAX746, discussed in a separate data sheet, functions similarly to the MAX747, but it drives N-channel logic level FETs on the high side.

Data Sheet

Download	Rev 1	(PDF, 152kB)
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Key Features

90% to 95% Efficiency for 50mA to 2.5A Output Currents
4V to 15V Input Voltage Range
Low 800µA Supply Current
0.6µA Shutdown Current
Drives External P-Channel FETs
Cycle-by-Cycle Current Limiting
2V ±1.5% Accurate Reference Output
Adjustable Soft-Start
Precision Comparator for Power-Fail or Low-Battery Warning

Applications/Uses

5V to 3.3V Green PC Applications
Battery-Powered Applications
Cell Phones
Notebook Power Supplies
PDAs and Other Handheld Devices

Diagram

Typical Operating Circuit

Product Guides

Thermal Management (PDF)

Wireless (PDF)

Reliability Reports

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Software/Models

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Ordering Information

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Tape and Reel

Sample

Part Number	Free Sample	Buy	Status	Recommended Replacement	Package: TYPE PINS FOOTPRINT DRAWING CODE/VAR *	Temp	RoHS/Lead-Free? Materials Analysis
MAX747CPD		N/A	No Longer Available	MAX1745	PDIP(N);14 pin;158.4 mm² Outline Drawing:21-0043 (PDF) Land Pattern: Not Applicable Use pkgcode/variation: P14-4*	0°C to +70°C	RoHS/Lead-Free: No Materials Analysis
MAX747CPD+		N/A	No Longer Available	MAX1745	PDIP(N);14 pin;158.4 mm² Outline Drawing:21-0043 (PDF) Land Pattern: Not Applicable Use pkgcode/variation: P14+4*	0°C to +70°C	RoHS/Lead-Free: Lead Free Materials Analysis
MAX747CSD		N/A	No Longer Available	MAX1745	SOIC(N);14 pin;54.2 mm² Outline Drawing:21-0041 (PDF) Land Pattern: 90-0112 (PDF) Use pkgcode/variation: S14-1*	0°C to +70°C	RoHS/Lead-Free: No Materials Analysis
MAX747CSD+		N/A	No Longer Available	MAX1745	SOIC(N);14 pin;54.2 mm² Outline Drawing:21-0041 (PDF) Land Pattern: 90-0112 (PDF) Use pkgcode/variation: S14+1*	0°C to +70°C	RoHS/Lead-Free: Lead Free Materials Analysis
MAX747CSD+T		N/A	No Longer Available	MAX1745	N.SO; Land Pattern: Not Available	0°C to +70°C	See data sheet
MAX747CSD-T		N/A	No Longer Available	MAX1745	N.SO;14 pin Land Pattern: Not Available	0°C to +70°C	See data sheet
MAX747EPD		N/A	No Longer Available	MAX1745	PDIP(N);14 pin;158.4 mm² Outline Drawing:21-0043 (PDF) Land Pattern: Not Applicable Use pkgcode/variation: P14-4*	-40°C to +85°C	RoHS/Lead-Free: No Materials Analysis
MAX747ESD		N/A	No Longer Available	MAX1745	SOIC(N);14 pin;54.2 mm² Outline Drawing:21-0041 (PDF) Land Pattern: 90-0112 (PDF) Use pkgcode/variation: S14-1*	-40°C to +85°C	RoHS/Lead-Free: No Materials Analysis
MAX747ESD+		N/A	No Longer Available	MAX1745	SOIC(N);14 pin;54.2 mm² Outline Drawing:21-0041 (PDF) Land Pattern: 90-0112 (PDF) Use pkgcode/variation: S14+1*	-40°C to +85°C	RoHS/Lead-Free: Lead Free Materials Analysis
MAX747ESD+T		N/A	No Longer Available	MAX1745	N.SO; Land Pattern: Not Available	-40°C to +85°C	See data sheet
Part Number	Free Sample	Buy	Status	Recommended Replacement	Package: TYPE PINS FOOTPRINT DRAWING CODE/VAR *	Temp	RoHS/Lead-Free? Materials Analysis
MAX747ESD-T		N/A	No Longer Available	MAX1745	N.SO;14 pin Land Pattern: Not Available	-40°C to +85°C	See data sheet
MAX747MJD		N/A	No Longer Available	MAX1745	CDIP(N);14 pin;162.1 mm² Outline Drawing:21-0045 (PDF) Land Pattern: Not Applicable Use pkgcode/variation: J14-3*	-55°C to +125°C	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.

Notes and Comments

Drives external P-channel FET

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High-Efficiency, PWM, Step-Down, N-Channel DC-DC Controller

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Information Index

Overview		Technical Documents		Ordering Info		Related Products
Description Key Features Applications/Uses Key Specifications Diagram Notes and Comments		Data Sheet Application Notes Evaluation Kits Product Guides Reliability Reports Software/Models		Price and Availability Samples Buy Online Package Information Lead-Free Information		Similar Products by Function Similar Products by Application Evaluation Kits Products with Similar Part Numbers Products Used With This

Document Ref.: 19-0171 Rev 1; 1993-09-01
This page last modified: 2007-05-30