MAX1920, MAX1921 Low-Voltage, 400mA Step-Down DC-DC Converters in SOT23

Description

The MAX1920/MAX1921 step-down converters deliver over 400mA to outputs as low as 1.25V. These converters use a unique proprietary current-limited control scheme that achieves over 90% efficiency. These devices maintain extremely low quiescent supply current (50µA), and their high 1.2MHz (max) operating frequency permits small, low-cost external components. This combination makes the MAX1920/MAX1921 excellent high-efficiency alternatives to linear regulators in space-constrained applications.

Internal synchronous rectification greatly improves efficiency and eliminates the external Schottky diode required in conventional step-down converters. Both devices also include internal digital soft-start to limit input current upon startup and reduce input capacitor requirements.

The MAX1920 provides an adjustable output voltage (1.25V to 4V). The MAX1921 provides factory-preset output voltages (see the Selector Guide). Both are available in space-saving 6-pin SOT23 packages. The MAX1920 is also available in a 6-pin TDFN package.

Key Features

Applications/Uses

	400mA Guaranteed Output Current
	Internal Synchronous Rectifier for >90% Efficiency
	Tiny 6-Pin SOT23 Package
	Up to 1.2MHz Switching Frequency for Small External Components
	50µA Quiescent Supply Current
	0.1µA Logic-Controlled Shutdown
	2V to 5.5V Input Range
	Fixed 1.5V, 1.8V, 2.5V, 3V, and 3.3V Output Voltages (MAX1921)
	Adjustable Output Voltage (MAX1920)
	±1.5% Initial Accuracy
	Soft-Start Limits Startup Current

	Battery-Powered Applications
	CDMA Power Amplifier Supply
	Next-Generation Wireless handsets
	PDAs, Palmtops, and Handy Terminals

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^**

MAX1920

5.5

1.25

0.4

Resistor

0.07

1200

•	Adjustable Frequency

•	Current Limit

•	Internal Power Switches

•

Shutdown

•	Soft Start

•	Synchronous Rectifier

Yes

SOT-23/6
THIN QFN (Dual)/6

Yes

-40 to +85

$1.35 @ 1k

MAX1921

1.5

3.3

1.5
1.8
2.5
3.3

Preset
Resistor

SOT-23/6

$1.35 @ 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^**

MAX1920

Step-Down

5.5

1.25

0.4

0.07

1200

Yes

SOT-23/6
THIN QFN (Dual)/6

$1.35 @ 1k

MAX1921

1.5
1.8
2.5
3.3

SOT-23/6

$1.35 @ 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.

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: 1-26 of 26

MAX1920

Free
Sample

Buy

Package:	TYPE PINS FOOTPRINT
	DRAWING CODE/VAR *

Temp

RoHS/Lead-Free?
Materials Analysis

MAX1920EUT

SOT-23;6 pin;
Dwg: 21-0058I (PDF)
Use pkgcode/variation: U6SN-1*

-40°C to +85°C

RoHS/Lead-Free: No
Materials Analysis

MAX1920EUT+

SOT-23;6 pin;
Dwg: 21-0058I (PDF)
Use pkgcode/variation: U6SN+1*

-40°C to +85°C

RoHS/Lead-Free: Lead Free
Materials Analysis

MAX1920EUT+T

SOT-23;6 pin;
Dwg: 21-0058I (PDF)
Use pkgcode/variation: U6SN+1*

-40°C to +85°C

RoHS/Lead-Free: Lead Free
Materials Analysis

MAX1920EUT-T

SOT-23;6 pin;
Dwg: 21-0058I (PDF)
Use pkgcode/variation: U6SN-1*

-40°C to +85°C

RoHS/Lead-Free: No
Materials Analysis

MAX1920ETT+T

TDFN;6 pin;
Dwg: 21-0137I (PDF)
Use pkgcode/variation: T633+2*

-40°C to +85°C

RoHS/Lead-Free: Lead Free
Materials Analysis

MAX1920ETT+

TDFN;6 pin;
Dwg: 21-0137I (PDF)
Use pkgcode/variation: T633+2*

-40°C to +85°C

RoHS/Lead-Free: Lead Free
Materials Analysis

MAX1921

Free
Sample

Buy

Package:	TYPE PINS FOOTPRINT
	DRAWING CODE/VAR *

Temp

RoHS/Lead-Free?
Materials Analysis

MAX1921EUT30+

SOT-23;6 pin;
Dwg: 21-0058I (PDF)
Use pkgcode/variation: U6SN+1*

-40°C to +85°C

RoHS/Lead-Free: Lead Free
Materials Analysis

MAX1921EUT30+T

SOT-23;6 pin;
Dwg: 21-0058I (PDF)
Use pkgcode/variation: U6SN+1*

-40°C to +85°C

RoHS/Lead-Free: Lead Free
Materials Analysis

MAX1921EUT33+T

SOT-23;6 pin;
Dwg: 21-0058I (PDF)
Use pkgcode/variation: U6SN+1*

-40°C to +85°C

RoHS/Lead-Free: Lead Free
Materials Analysis

MAX1921EUT15+T

SOT-23;6 pin;
Dwg: 21-0058I (PDF)
Use pkgcode/variation: U6SN+1*

-40°C to +85°C

RoHS/Lead-Free: Lead Free
Materials Analysis

MAX1921EUT15+

SOT-23;6 pin;
Dwg: 21-0058I (PDF)
Use pkgcode/variation: U6SN+1*

-40°C to +85°C

RoHS/Lead-Free: Lead Free
Materials Analysis

MAX1921EUT33+

SOT-23;6 pin;
Dwg: 21-0058I (PDF)
Use pkgcode/variation: U6SN+1*

-40°C to +85°C

RoHS/Lead-Free: Lead Free
Materials Analysis

MAX1921EUT15

SOT-23;6 pin;
Dwg: 21-0058I (PDF)
Use pkgcode/variation: U6SN-1*

-40°C to +85°C

RoHS/Lead-Free: No
Materials Analysis

MAX1921EUT18

SOT-23;6 pin;
Dwg: 21-0058I (PDF)
Use pkgcode/variation: U6SN-1*

-40°C to +85°C

RoHS/Lead-Free: No
Materials Analysis

MAX1921EUT18+

SOT-23;6 pin;
Dwg: 21-0058I (PDF)
Use pkgcode/variation: U6SN+1*

-40°C to +85°C

RoHS/Lead-Free: Lead Free
Materials Analysis

MAX1921EUT33

SOT-23;6 pin;
Dwg: 21-0058I (PDF)
Use pkgcode/variation: U6SN-1*

-40°C to +85°C

RoHS/Lead-Free: No
Materials Analysis

MAX1921EUT30

SOT-23;6 pin;
Dwg: 21-0058I (PDF)
Use pkgcode/variation: U6SN-1*

-40°C to +85°C

RoHS/Lead-Free: No
Materials Analysis

MAX1921EUT25

SOT-23;6 pin;
Dwg: 21-0058I (PDF)
Use pkgcode/variation: U6SN-1*

-40°C to +85°C

RoHS/Lead-Free: No
Materials Analysis

MAX1921EUT25+

SOT-23;6 pin;
Dwg: 21-0058I (PDF)
Use pkgcode/variation: U6SN+1*

-40°C to +85°C

RoHS/Lead-Free: Lead Free
Materials Analysis

MAX1921EUT18+T

SOT-23;6 pin;
Dwg: 21-0058I (PDF)
Use pkgcode/variation: U6SN+1*

-40°C to +85°C

RoHS/Lead-Free: Lead Free
Materials Analysis

MAX1921EUT33-T

SOT-23;6 pin;
Dwg: 21-0058I (PDF)
Use pkgcode/variation: U6SN-1*

-40°C to +85°C

RoHS/Lead-Free: No
Materials Analysis

MAX1921EUT30-T

SOT-23;6 pin;
Dwg: 21-0058I (PDF)
Use pkgcode/variation: U6SN-1*

-40°C to +85°C

RoHS/Lead-Free: No
Materials Analysis

MAX1921EUT25-T

SOT-23;6 pin;
Dwg: 21-0058I (PDF)
Use pkgcode/variation: U6SN-1*

-40°C to +85°C

RoHS/Lead-Free: No
Materials Analysis

MAX1921EUT18-T

SOT-23;6 pin;
Dwg: 21-0058I (PDF)
Use pkgcode/variation: U6SN-1*

-40°C to +85°C

RoHS/Lead-Free: No
Materials Analysis

MAX1921EUT15-T

SOT-23;6 pin;
Dwg: 21-0058I (PDF)
Use pkgcode/variation: U6SN-1*

-40°C to +85°C

RoHS/Lead-Free: No
Materials Analysis

MAX1921EUT25+T

SOT-23;6 pin;
Dwg: 21-0058I (PDF)
Use pkgcode/variation: U6SN+1*

-40°C to +85°C

RoHS/Lead-Free: Lead Free
Materials Analysis