Maxim > Products > Power and Battery Management > MAX1640, MAX1641

MAX1640, MAX1641

Adjustable-Output, Switch-Mode Current Sources with Synchronous Rectifier

High-Accuracy Current Sources Remain Cool While Fast Charging

Overview

Technical Documents

Ordering Info

Status

Active: In Production.

Description

The MAX1640/MAX1641 CMOS, adjustable-output, switch-mode current sources operate from a +5.5V to +26V input, and are ideal for microprocessor-controlled battery chargers. Charging current, maximum output voltage, and pulse-trickle charge are programmed with external resistors. Programming the off-time modifies the switching frequency, suppressing undesirable harmonics in noise-sensitive circuits. The MAX1640's high-side current sensing allows the load to connect directly to ground, eliminating ground-potential errors. The MAX1641 incorporates a low-side current sense.

The MAX1640/MAX1641 step-down pulse-width-modulation (PWM) controllers use an external P-channel MOSFET switch and an optional, external N-channel MOSFET synchronous rectifier for increased efficiency. An internal low-dropout linear regulator provides power for the internal reference and circuitry as well as the gate drive for the N-channel synchronous rectifier.

The MAX1640/MAX1641 are available in space-saving, 16-pin narrow QSOP packages.

Data Sheet

Download	Rev 2	(PDF, 288kB)
E-Mail

An evaluation kit is available: MAX1640EVKIT

Key Features

95% Efficiency
+5.5V to +26V Input Supply Range
2V to 24V Adjustable-Output Voltage Range
100% Maximum Duty Cycle (Low Dropout)
Up to 500kHz PWM Operation
Optional Synchronous Rectifier
16-Pin QSOP Package
Current-Sense Accuracy:
- 2% (MAX1641)
- 5.3% (MAX1640)

Applications/Uses

Backup Battery Charger
Battery-Powered Applications
Cell Phones
Cordless Phones
Handy Terminals
Laptop, Notebook, and Palmtop Computers
PCS Phones
Portable Consumer Products

Key Specifications:

Battery Chargers

Part Number

Cell Chemistry

NiMH/ NiCd Cells

Lithium Ion Cells

Protected V_IN
(V)

Charging V_IN
(V)

Charge Rate Set by

Charge Termination

Charge Regulation

EV Kit

Oper. Temp.
(°C)

Package/Pins

Smallest Available Pckg.
(mm²)

Budgetary Price

max

max w/pins

See Notes

MAX1640

Li-Ion

Li-Polymer

NiCd

NiMH

2
3
4
5
6
7
8
9
10
11
12
13
14
15
16

Resistor

External Control

Switchmode

Yes

-40 to +85

30.9

MAX1641

See All Battery Chargers (70)

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

Synchronous rectifier high-side current sensing (MAX1640)
Low-side current sensing (MAX1641)

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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.: 19-1245 Rev 2; 2010-03-08
This page last modified: 2010-03-08