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MAX1623

3A, Low-Voltage, Step-Down Regulator with Synchronous Rectification and Internal Switches

Industry's Smallest 3A DC-DC with Synchronous Rectifier

Overview

Technical Documents

Ordering Info

Status

Active: In Production.

Description

The MAX1623 switch-mode buck regulator with synchronous rectification provides local CPU and bus-termination power in notebook and desktop computers. An internal 55mΩ (typ), 3A PMOS power switch and 60mΩ (typ), 3A NMOS synchronous-rectifier switch deliver continuous load currents up to 3A from a 5V supply with 95% typical efficiency. Output accuracy is ±1%, including line and load regulation.

The MAX1623 features constant-off-time, current-mode pulse-width-modulation (PWM) control with switching frequencies as high as 350kHz. An external resistor at the TOFF pin sets the off-time, allowing optimum design flexibility in terms of switching frequency, output switching noise, and inductor size. This device is available in a space-saving 20-pin SSOP package.

Data Sheet

Download	Rev 2	(PDF, 256kB)
E-Mail

An evaluation kit is available: MAX1623EVKIT

Key Features

±1% Output Accuracy, Including Line and Load Regulation
94% Efficiency
Internal Switches
- 55mΩ PMOS Power Switch
- 60mΩ NMOS Synchronous-Rectifier Switch
Guaranteed 3A Load Capability
Minimal External Components
Pin-Selectable Fixed 3.3V, 2.5V, or Adjustable (1.1V to 3.8V) Output Voltage
4.5V to 5.5V Input Voltage Range
400µA (typ) Supply Current
<1µA Shutdown Supply Current
Constant-Off-Time PWM Operation
Switching Frequencies Up to 350kHz
Idle Mode™ Operation at Light Loads
Thermal Shutdown Protection
Available in 20-Pin SSOP

Applications/Uses

5V to 3.3V Conversion
CPU Daughter Card Supply
Desktop Computer Bus-Termination Supply
DSP Supply
Notebook Computer CPU I/O Supply

Key Specifications:

Step-Down Switching Regulators

Part Number

V_IN
(V)

V_OUT
(V)

Preset V_OUT
(V)

Max. I_OUT
(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

MAX1623

4.5

5.5

1.1

3.8

2.5

3.3

Preset

Resistor

350

SSOP/20

57.9

$5.15 @1k

See All Step-Down Switching Regulators (288)

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.

Diagram

Typical Operating Circuit

Notes and Comments

No external Schottky required. Constant off time, current-mode PWM operation. Lossless current sensing eliminates external current-sense resistor

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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.: 19-1436 Rev 2; 2002-08-02
This page last modified: 2007-07-23