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MAX1678

1 Cell to 2 Cell, Low-Noise, High-Efficiency, Step-Up DC-DC Converter

Efficient 1-Cell Step-Up Converter for Pagers

Overview

Technical Documents

Ordering Info

Status

Active: In Production.

Description

The MAX1678 is a high-efficiency, low-voltage, synchronous-rectified, step-up DC-DC converter intended for use in devices powered by 1 to 3-cell alkaline, NiMH, or NiCd batteries or a 1-cell lithium battery. It guarantees a 0.87V start-up voltage and features a low 37µA quiescent supply current.

The device includes a 1Ω, N-channel MOSFET power switch, a synchronous rectifier that acts as the catch diode, a reference, pulse-frequency-modulation (PFM) control circuitry, and circuitry to reduce inductor ringing-all in an ultra-small, 1.1mm-high µMAX® package.

The output voltage is preset to 3.3V or can be adjusted from +2V to +5.5V using only two resistors. Efficiencies up to 90% are achieved for loads up to 50mA. The device also features an independent undervoltage comparator (PFI/PFO) and a logic-controlled 2µA shutdown mode.

Data Sheet

Download	Rev 0	(PDF, 176kB)
E-Mail

An evaluation kit is available: MAX1678EVKIT

Key Features

0.87V Guaranteed Start-Up
Up to 90% Efficiency
Built-In Synchronous Rectifier (no external diode)
Ultra-Small µMAX Package, 1.1mm High
37µA Quiescent Current (85µA from 1.5V battery)
2µA Logic-Controlled Shutdown
Power-Fail Detector
Dual Mode™ Output: Fixed 3.3V
Dual Mode Adjustable 2V to 5.5V
45mA Output Current at 3.3V for 1-Cell Input
90mA Output Current at 3.3V for 2-Cell Input
Inductor-Damping Switch Suppresses EMI

Applications/Uses

Pagers
Personal Medical Monitors
Pointing Devices
Remote Controls
Single-Cell Battery-Powered Devices

Key Specifications:

Step-Up Switching Regulators

Part Number

V_IN
(V)

V_OUT
(V)

Preset V_OUT
(V)

Max. I_OUT
(A)

Output Adjust. Method

DC-DC Outputs

Package/Pins

Smallest Available Pckg.
(mm²)

Budgetary Price

min

max

min

max

≥

≤

max w/pins

See Notes

MAX1678

0.7

5.5

0.09

Preset

Resistor

µMAX/8

15.6

$1.82 @1k

See All Step-Up Switching Regulators (95)

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. Power fail detector. Ideally suitable for pagers, remote controls, detectors and other 1-cell operated portables

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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.: 19-1381 Rev 0; 1998-07-01
This page last modified: 2007-06-01