MAX1556, MAX1557 16µA IQ, 1.2A PWM Step-Down DC-DC Converters

Description

The MAX1556/MAX1556A/MAX1557 are low-operating-current (16µA), fixed-frequency step-down regulators. High efficiency, low-quiescent operating current, low dropout, and minimal (27µA) quiescent current in dropout make these converters ideal for powering portable devices from 1-cell Li-ion or 3-cell alkaline/NiMH batteries. The MAX1556 delivers up to 1.2A; has pinselectable 1.8V, 2.5V, and 3.3V outputs; and is also adjustable. The MAX1557 delivers up to 600mA; has pin-selectable 1V, 1.3V, and 1.5V outputs; and is also adjustable.

The MAX1556/MAX1556A/MAX1557 contain a low-on-resistance internal MOSFET switch and synchronous rectifier to maximize efficiency and dropout performance while minimizing external component count. A proprietary topology offers the benefits of a high fixed-frequency operation while still providing excellent efficiency at both light and full loads. A 1MHz PWM switching frequency keeps components small. Both devices also feature an adjustable soft-start to minimize battery transient loading.

The MAX1556/MAX1556A/MAX1557 are available in a tiny 10-pin TDFN (3mm x 3mm) package.

Key Features

Applications/Uses

Up to 97% Efficiency
95% Efficiency at 1mA Load Current
Low 16µA Quiescent Current
1MHz PWM Switching
Tiny 3.3µH Inductor
Selectable 3.3V, 2.5V, 1.8V, 1.5V, 1.3V, 1.2V, 1.0V, and Adjustable Output
1.2A Guaranteed Output Current (MAX1556/MAX1556A)
Voltage Positioning Optimizes Load-Transient Response
Low 27µA Quiescent Current in Dropout
Low 0.1µA Shutdown Current
No External Schottky Diode Required
Analog Soft-Start with Zero Overshoot Current
Small, 10-Pin, 3mm x 3mm TDFN Package

	Cell Phones/Smartphones
	Digital Cameras and Camcorders
	Handheld Instruments
	PDAs and Palmtop Computers
	Portable MP3 and DVD Players

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)

Fixed Freq/PWM Operation

Operating Freq. (kHz)

Internal Power Switch(es)

Synchronous Rectifier

Package

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

Price^**

MAX1556

Step-Down

2.6

5.5

1.8
2.5
3.3

0.75

5.5

1.2

0.016

Yes

1000

Yes

THIN QFN (Dual)/10

$1.55 @ 1k

MAX1557

1.3
1.5

0.6

$1.45 @ 1k

See All Switch-Mode DC-DC Power Supplies (418)

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: 1-10 of 10

MAX1556

Free
Sample

Buy

Package:	TYPE PINS FOOTPRINT
	DRAWING CODE/VAR *

Temp

RoHS/Lead-Free?
Materials Analysis

MAX1556AETB+T

THIN QFN (Dual);10 pin;10 mm²
Dwg: 21-0137I (PDF)
Use pkgcode/variation: T1033+1*

-40°C to +85°C

RoHS/Lead-Free: Lead Free
Materials Analysis

MAX1556AETB+

THIN QFN (Dual);10 pin;10 mm²
Dwg: 21-0137I (PDF)
Use pkgcode/variation: T1033+1*

-40°C to +85°C

RoHS/Lead-Free: Lead Free
Materials Analysis

MAX1556ETB

THIN QFN (Dual);10 pin;10 mm²
Dwg: 21-0137I (PDF)
Use pkgcode/variation: T1033-1*

-40°C to +85°C

RoHS/Lead-Free: No
Materials Analysis

MAX1556ETB+

THIN QFN (Dual);10 pin;10 mm²
Dwg: 21-0137I (PDF)
Use pkgcode/variation: T1033+1*

-40°C to +85°C

RoHS/Lead-Free: Lead Free
Materials Analysis

MAX1556ETB+T

THIN QFN (Dual);10 pin;10 mm²
Dwg: 21-0137I (PDF)
Use pkgcode/variation: T1033+1*

-40°C to +85°C

RoHS/Lead-Free: Lead Free
Materials Analysis

MAX1556ETB-T

THIN QFN (Dual);10 pin;10 mm²
Dwg: 21-0137I (PDF)
Use pkgcode/variation: T1033-1*

-40°C to +85°C

RoHS/Lead-Free: No
Materials Analysis

MAX1557

Free
Sample

Buy

Package:	TYPE PINS FOOTPRINT
	DRAWING CODE/VAR *

Temp

RoHS/Lead-Free?
Materials Analysis

MAX1557ETB+

THIN QFN (Dual);10 pin;10 mm²
Dwg: 21-0137I (PDF)
Use pkgcode/variation: T1033+1*

-40°C to +85°C

RoHS/Lead-Free: Lead Free
Materials Analysis

MAX1557ETB

THIN QFN (Dual);10 pin;10 mm²
Dwg: 21-0137I (PDF)
Use pkgcode/variation: T1033-1*

-40°C to +85°C

RoHS/Lead-Free: No
Materials Analysis

MAX1557ETB+T

THIN QFN (Dual);10 pin;10 mm²
Dwg: 21-0137I (PDF)
Use pkgcode/variation: T1033+1*

-40°C to +85°C

RoHS/Lead-Free: Lead Free
Materials Analysis

MAX1557ETB-T

THIN QFN (Dual);10 pin;10 mm²
Dwg: 21-0137I (PDF)
Use pkgcode/variation: T1033-1*

-40°C to +85°C

RoHS/Lead-Free: No
Materials Analysis

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MAX8560, MAX8561, MAX8562 4MHz, 500mA Synchronous Step-Down DC-DC Converters in Thin SOT and TDFN