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MAX1684

Low-Noise, 14V Input, 1A, PWM Step-Down Converters

Smallest 1.5A Step-Down DC-DC for Hand-Held PC Offers 96% Efficiency

Data Sheet

Please check latest availability status for a specific part variant.

Overview

Description

The MAX1684/MAX1685 are high-efficiency, internal-switch, pulse-width modulation (PWM) step-down switching regulators intended to power cellular phones, communicating PDAs, and handy-terminals. These devices deliver a guaranteed 1A output current from two lithium-ion (Li+) batteries. Their wide-input voltage range of 2.7V to 14V gives design flexibility and allows batteries to charge from a wall cube, since the ICs operate at the higher voltages that occur when the battery is removed. The output voltage is preset to 3.3V or can be externally adjusted from 1.25V to V_IN.

The low on-resistance power switch and built-in synchronous rectifier provide high efficiencies of up to 96%. There are four modes of operation: fixed-frequency, normal, low-power, and shutdown. The fixed-frequency PWM mode of operation offers excellent noise characteristics. The normal mode maintains high efficiency at all loads. The low-power mode is used to conserve power in standby or when full load is not required. The shutdown mode is used to power down the device for minimal current draw.

The MAX1684 runs at 300kHz for applications that require highest efficiency. The MAX1685 runs at 600kHz to allow the use of smaller external components. These devices can also be synchronized to an external clock. Other features include a 100% duty cycle for low-dropout applications, an auxiliary 3V/5mA output, and a 1% accurate reference.

Both devices are available in a space-saving 16-QSOP package. An evaluation kit is also available to help speed designs. For a similar device in a 10-pin µMAX® package with lower input voltage requirements (5.5V max), refer to the MAX1692 data sheet.

MAX1684, MAX1685: Typical Operating Circuit

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Key Features

Up to 96% Efficiency
1A Guaranteed Output Current
100% Duty Cycle in Dropout
2.7V to 14V Input Range (15V Absolute Max)
±1% Accurate Reference Output
0.24Ω P-Channel On-Resistance
Synchronizable Switching Frequency
Fixed-Frequency PWM Operation
- 300kHz (MAX1684)
- 600kHz (MAX1685)
150µA Normal-Mode Quiescent Current
25µA Low-Power Mode Quiescent Current
2µA Shutdown Current
Dual Mode™ Fixed 3.3V (±1%) Output or Adjustable Output (1.25V to V_IN)
Small 16-QSOP Package
Auxiliary Output (CVL): 3V/5mA

Applications/Uses

Cell Phones
Computer Peripherals
PDAs and Handy-Terminals
Personal Communicators
Two-Way Radios and Walkie-Talkies

Parametric Specs

Part Number

V_IN
(V)

V_OUT1
(V)

Preset V_OUT
(V)

Output Adjust. Method

I_OUT1
(A)

Switch Type

DC-DC Outputs

Oper. Freq.
(kHz)

Package/Pins

Budgetary
Price

min

max

min

max

See Notes

MAX1684

2.7

1.25

3.3

Preset

Resistor

Internal

300

QSOP/16

$3.75 @1k

MAX1685

600

QSOP/16

See All Step-Down Switching Regulators (380)

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 and version-specific prices and delivery, please see the price and availability page or contact an authorized distributor.

Design Resources

MAX1685EVKIT: Evaluation Kit for the MAX1684, MAX1685

Quality And Environmental

Device	Fab Process	Technology	Sample size	Rejects	FIT at 25°C	FIT at 55°C

Note : The failure rates are summarized by technology and mapped to the associated material part numbers. The failure rates are highly dependent on the number of units tested.

Quality Management System >
Environmental Management System >

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