MAX1649, MAX1651 5V/3.3V or Adjustable, High-Efficiency, Low-Dropout, Step-Down DC-DC Controller

Description

The MAX1649/MAX1651 BiCMOS, step-down, DC-DC switching controllers provide high efficiency over loads ranging from 1mA to more than 2.5A. A unique, current-limited pulse-frequency-modulated (PFM) control scheme gives these devices the benefits of pulse-width-modulation (PWM) converters (high efficiency at heavy loads), while using only 100µA of supply current (vs. 2mA to 10mA for PWM converters). Dropout performance down to 300mV is provided by a high switch duty cycle (96.5%) and a low current-sense threshold (110mV).

A high switching frequency (up to 300kHz) allows these devices to use miniature external components.

The MAX1649/MAX1651 have dropout voltages less than 0.3V at 500mA and accept input voltages up to 16V. Output voltages are preset at 5V (MAX1649), or 3.3V (MAX1651). They can also be adjusted to any voltage from 1.5V to the input voltage by using two resistors.

These step-down controllers drive external P-channel MOSFETs at loads greater than 12.5W. If less power is required, use the MAX639/MAX640/MAX653 step-down converters with on-chip FETs, which allow up to a 225mA load current.

Key Features

Applications/Uses

More than 90% Efficiency (10mA to 1.5A Loads)
More than 12.5W Output Power
Less than 0.3V Dropout Voltage at 500mA
100µA Max Quiescent Supply Current
5µA Max Shutdown Supply Current
16V Max Input Voltage
5V (MAX1649), 3.3V (MAX1651), or Adjustable Output Voltage
Current-Limited Control Scheme
Up to 300kHz Switching Frequency
Up to 96.5% Duty Cycle

	5V to 3.3V Green PC Applications
	Battery-Powered Applications
	High-Efficiency Step-Down Regulation
	PDAs

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)

Package

Smallest Available Package (max w/pins) (mm²)

Price^**

MAX1649

1.5

5.0

2.5

Preset
Resistor

0.1

300

PDIP(N)/8
SOIC(N)/8

$2.07 @ 1k

MAX1651

3.3

$2.07 @ 1k

See All Step-Down Switching Regulators (252)

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.

Ordering Information

Notes:

Other options and links for purchasing parts are listed at: http://www.maxim-ic.com/sales.
Didn't Find What You Need? Ask our applications engineers. Expert assistance in finding parts, usually within one business day.
Part number suffixes: T or T&R = tape and reel; + = RoHS/lead-free; # = RoHS/lead-exempt. More: SeeFull Data Sheet or Part Naming Conventions.
* Some packages have variations, listed on the drawing. "PkgCode/Variation" tells which variation the product uses. Note that "+", "#", "-" in the part number suffix describes RoHS status. Package drawings may show a different suffix character.

Devices: 1-23 of 23

MAX1649

Free
Sample

Buy

Package:	TYPE PINS FOOTPRINT
	DRAWING CODE/VAR *

Temp

RoHS/Lead-Free?
Materials Analysis

MAX1649MJA

Land Pattern: Not Available

See data sheet

MAX1649CPA+

PDIP(N);8 pin;80 mm²
Outline Drawing: 21-0043 (PDF)
Land Pattern: Not Applicable
Use pkgcode/variation: P8+2*

0°C to +70°C

RoHS/Lead-Free: Lead Free
Materials Analysis

MAX1649CPA

PDIP(N);8 pin;80 mm²
Outline Drawing: 21-0043 (PDF)
Land Pattern: Not Applicable
Use pkgcode/variation: P8-2*

0°C to +70°C

RoHS/Lead-Free: No
Materials Analysis

MAX1649EPA

PDIP(N);8 pin;80 mm²
Outline Drawing: 21-0043 (PDF)
Land Pattern: Not Applicable
Use pkgcode/variation: P8-2*

-40°C to +85°C

RoHS/Lead-Free: No
Materials Analysis

MAX1649CSA

SOIC(N);8 pin;31 mm²
Outline Drawing: 21-0041 (PDF)
Land Pattern: 90-0096 (PDF)
Use pkgcode/variation: S8-4*

0°C to +70°C

RoHS/Lead-Free: No
Materials Analysis

MAX1649CSA-T

SOIC(N);8 pin;31 mm²
Outline Drawing: 21-0041 (PDF)
Land Pattern: 90-0096 (PDF)
Use pkgcode/variation: S8-4*

0°C to +70°C

RoHS/Lead-Free: No
Materials Analysis

MAX1649CSA+

SOIC(N);8 pin;31 mm²
Outline Drawing: 21-0041 (PDF)
Land Pattern: 90-0096 (PDF)
Use pkgcode/variation: S8+4*

0°C to +70°C

RoHS/Lead-Free: Lead Free
Materials Analysis

MAX1649CSA+T

SOIC(N);8 pin;31 mm²
Outline Drawing: 21-0041 (PDF)
Land Pattern: 90-0096 (PDF)
Use pkgcode/variation: S8+4*

0°C to +70°C

RoHS/Lead-Free: Lead Free
Materials Analysis

MAX1649ESA+

SOIC(N);8 pin;31 mm²
Outline Drawing: 21-0041 (PDF)
Land Pattern: 90-0096 (PDF)
Use pkgcode/variation: S8+4*

-40°C to +85°C

RoHS/Lead-Free: Lead Free
Materials Analysis

MAX1649ESA+T

SOIC(N);8 pin;31 mm²
Outline Drawing: 21-0041 (PDF)
Land Pattern: 90-0096 (PDF)
Use pkgcode/variation: S8+4*

-40°C to +85°C

RoHS/Lead-Free: Lead Free
Materials Analysis

MAX1649ESA-T

SOIC(N);8 pin;31 mm²
Outline Drawing: 21-0041 (PDF)
Land Pattern: 90-0096 (PDF)
Use pkgcode/variation: S8-4*

-40°C to +85°C

RoHS/Lead-Free: No
Materials Analysis

MAX1649ESA

SOIC(N);8 pin;31 mm²
Outline Drawing: 21-0041 (PDF)
Land Pattern: 90-0096 (PDF)
Use pkgcode/variation: S8-4*

-40°C to +85°C

RoHS/Lead-Free: No
Materials Analysis

MAX1651

Free
Sample

Buy

Package:	TYPE PINS FOOTPRINT
	DRAWING CODE/VAR *

Temp

RoHS/Lead-Free?
Materials Analysis

MAX1651MJA

Land Pattern: Not Available

See data sheet

MAX1651CPA

PDIP(N);8 pin;80 mm²
Outline Drawing: 21-0043 (PDF)
Land Pattern: Not Applicable
Use pkgcode/variation: P8-2*

0°C to +70°C

RoHS/Lead-Free: No
Materials Analysis

MAX1651EPA

PDIP(N);8 pin;80 mm²
Outline Drawing: 21-0043 (PDF)
Land Pattern: Not Applicable
Use pkgcode/variation: P8-2*

-40°C to +85°C

RoHS/Lead-Free: No
Materials Analysis

MAX1651ESA+

SOIC(N);8 pin;31 mm²
Outline Drawing: 21-0041 (PDF)
Land Pattern: 90-0096 (PDF)
Use pkgcode/variation: S8+4*

-40°C to +85°C

RoHS/Lead-Free: Lead Free
Materials Analysis

MAX1651ESA+T

SOIC(N);8 pin;31 mm²
Outline Drawing: 21-0041 (PDF)
Land Pattern: 90-0096 (PDF)
Use pkgcode/variation: S8+4*

-40°C to +85°C

RoHS/Lead-Free: Lead Free
Materials Analysis

MAX1651CSA+

SOIC(N);8 pin;31 mm²
Outline Drawing: 21-0041 (PDF)
Land Pattern: 90-0096 (PDF)
Use pkgcode/variation: S8+4*

0°C to +70°C

RoHS/Lead-Free: Lead Free
Materials Analysis

MAX1651CSA+T

SOIC(N);8 pin;31 mm²
Outline Drawing: 21-0041 (PDF)
Land Pattern: 90-0096 (PDF)
Use pkgcode/variation: S8+4*

0°C to +70°C

RoHS/Lead-Free: Lead Free
Materials Analysis

MAX1651CSA-T

SOIC(N);8 pin;31 mm²
Outline Drawing: 21-0041 (PDF)
Land Pattern: 90-0096 (PDF)
Use pkgcode/variation: S8-4*

0°C to +70°C

RoHS/Lead-Free: No
Materials Analysis

MAX1651CSA

SOIC(N);8 pin;31 mm²
Outline Drawing: 21-0041 (PDF)
Land Pattern: 90-0096 (PDF)
Use pkgcode/variation: S8-4*

0°C to +70°C

RoHS/Lead-Free: No
Materials Analysis

MAX1651ESA-T

SOIC(N);8 pin;31 mm²
Outline Drawing: 21-0041 (PDF)
Land Pattern: 90-0096 (PDF)
Use pkgcode/variation: S8-4*

-40°C to +85°C

RoHS/Lead-Free: No
Materials Analysis

MAX1651ESA

SOIC(N);8 pin;31 mm²
Outline Drawing: 21-0041 (PDF)
Land Pattern: 90-0096 (PDF)
Use pkgcode/variation: S8-4*

-40°C to +85°C

RoHS/Lead-Free: No
Materials Analysis

Related Products

MAX1626, MAX1627 5V/3.3V or Adjustable, 100% Duty Cycle, High-Efficiency, Step-Down DC-DC Controllers
MAX639, MAX640, MAX653 5V/3.3V/3V Adjustable, High-Efficiency, Low-I_Q, Step-Down DC-DC Converters