MAX1844 高速、降压型控制器，带有精确限流，用于笔记本电脑

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The MAX1844 pulse-width modulation (PWM) controller provides high efficiency, excellent transient response, and high DC output accuracy needed for stepping down high-voltage batteries to generate low-voltage CPU core or chipset/RAM supplies in notebook computers.

Maxim's proprietary Quick-PWM™ quick-response, constant-on-time PWM control scheme handles wide input/output voltage ratios with ease and provides 100ns “instant-on” response to load transients while maintaining a relatively constant switching frequency. Efficiency is enhanced by an ability to drive very large synchronous-rectifier MOSFETs. Accurate current sensing to ensure reliable overload protection is available using an external current-sense resistor in series with the synchronous rectifier. Alternatively, the synchronous rectifier itself can be used for less accurate current sensing at the lowest possible power dissipation.

Single-stage buck conversion allows the MAX1844 to directly step down high-voltage batteries for the highest possible efficiency. Alternatively, two-stage conversion (stepping down the 5V system supply instead of the battery) at a higher switching frequency allows the minimum possible physical size.

The MAX1844 is intended for CPU core, chipset, DRAM, or other low-voltage supplies as low as 1V. It is available in 20-pin QSOP, and QFN packages and includes both adjustable overvoltage and undervoltage protection.

For a dual step-down PWM controller with accurate current limit, refer to the MAX1845. The MAX1714/ MAX1715 single/dual PWM controllers are similar to the MAX1844/MAX1845 but do not use current-sense resistors.

关键特性

应用/使用

Ultra-High Efficiency
Accurate Current-Limit Option
Quick-PWM with 100ns Load-Step Response
1% V_OUT Accuracy Over Line and Load
1.8V/2.5V Fixed or 1V to 5.5V Adjustable Output Range
2V to 28V Battery Input Range
200/300/450/600kHz Switching Frequency
Adjustable Overvoltage Protection
Adjustable Undervoltage Protection
1.7ms Digital Soft-Start
Drives Large Synchronous-Rectifier FETs
2V ±1% Reference Output
Power-Good Window Comparator

	1.8V与2.5V电源
	芯片组/RAM供电，电压可低至1V
	CPU核电源
	笔记本电脑

Key Specifications: Step-Down Switching Regulators

Part Number

V_IN (min) (V)

V_IN (max) (V)

Min. V_OUT (V)

Max. V_OUT (V)

Preset V_OUT (V)

I_OUT (A)

Output Adj. Method

Operating Current, I_CC (max) (mA)

Number of DC-DC Outputs

Operating Freq. (kHz)

Features

EV-Kit

Package

RoHS Available

Operating Temp. Range (°C)

Price^**

MAX1844

5.5

1.8
2.5

Preset
Resistor

0.8

300

•	Adjustable Frequency

•	Current Limit

•	Fixed Frequency/ PWM Operation

•	Output Overvoltage Protection

•	Output Undervoltage Protection

•

Shutdown

•	Soft Start

•	Synchronous Rectifier

Yes

QFN/20
QSOP/20
THIN QFN/20

Yes

-40 to +85

$2.60 @ 1k

See All Step-Down Switching Regulators (223)

Key Specifications: Switch-Mode DC-DC Power Supplies

Part Number

Topology

V_IN (min) (V)

V_IN (max) (V)

Number of DC-DC Outputs

Preset V_OUT (V)

Digital/VID Programmed Output

Min. Adjustable V_OUT (V)

Max. Adjustable V_OUT (V)

I_OUT (A)

Operating Current, I_CC (max) (mA)

Operating Freq. (kHz)

Internal Power Switch(es)

Package

Price^**

MAX1844

Step-Down

1.8
2.5

5.5

0.8

300

QFN/20
QSOP/20
THIN QFN/20

$2.60 @ 1k

See All Switch-Mode DC-DC Power Supplies (429)

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.