LM20123 - 3A, 1.5MHz PowerWise Synchronous Buck Regulator

	LM20123 - 3A, 1.5MHz PowerWise Synchronous Buck Regulator

Datasheet	Packaging	Samples & Pricing	Eval. Boards	Reliability	Design Tools	Application Notes	Knowledge Base

Features

•	Input voltage range 2.95V to 5.5V
•	Accurate current limit minimizes inductor size
•	96% efficiency with 1.5 MHz switching frequency
•	32 mΩ integrated FET switches
•	Starts up into pre-biased loads
•	Output voltage tracking
•	Peak current mode control
•	Adjustable output voltage down to 0.8V
•	Adjustable Soft-Start with external capacitor
•	Precision enable pin with hysteresis
•	Integrated OVP, UVLO, power good and thermal shutdown
•	eTSSOP-16 exposed pad package

General Description

Applications

•	Simple to design, high efficiency point of load regulation from a 5V or 3.3V bus
•	High Performance DSPs, FPGAs, ASICs and microprocessors
•	Broadband, Networking and Optical Communications Infrastructure

Typical Application

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Parametric Table expand

Parametric Table collapse

Output Current 3000 mA

Input Min Voltage 2.95 Volt

Input Max Voltage 5.5 Volt

Output Min 0.8 Volt

Output Max 5 Volt

Frequency Min Undefined kHz

Frequency Max Undefined kHz

Efficiency (peak) 96 %

Output Current 3000 mA

Input Min Voltage 2.95 Volt

Input Max Voltage 5.5 Volt

Output Min 0.8 Volt

Output Max 5 Volt

Frequency Min Undefined kHz

Frequency Max Undefined kHz

Efficiency (peak) 96 %

On/Off Pin Yes

Error Flag Yes

SoftStart Yes

Sync Pin No

Inverting Undefined

Flyback Undefined

RegType Switching Regulator

Temperature Min -40 deg C

Temperature Max 125 deg C

Adjustable Output Yes

Adj Switch Frequency No

PWM Mode Current Mode Control

Topology Synchronous Buck

Special Features Undefined

Step-Down Yes

Multiple Output Capability No

Output Power Undefined Watt

Output Voltage Undefined Volt

Output Range 0.8V to 5.0V

Switching Frequency 1500 kHz

Feedback Voltage 0.8 Volt

Regulator Family LM20k

PowerWise Yes

Synchronous Rectification Yes

View Using Catalog

Typical Performance

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WEBENCH Live Simulation!

LM20123 WEBENCH® Custom Design/Analyze/Build It/Test It
2.95 <=	V in Lower V	<=	V in Upper V	<= 5.50
V out	0.80 <=		V	<= 4.00
I out			A	<= 3.00
Ambient Temperature			°C	<= 100
What are WEBENCH® tools?

Also Recommended

LM20124	4A, 1 MHz Switching Frequency
LM20125	5A, 500 KHz Switching Frequency
LM20133	3A, Input Synchronization (500 KHz - 1.5 MHz)
LM20134	4A, Input Synchronization (500 KHz - 1.5 MHz)
LM20143	3A, Adjustable Frequency (500 KHz - 1.5 MHz)
LM20144	4A, Adjustable Frequency (500 KHz - 1.5 MHz)
LM20145	5A, Adjustable Frequency (250 KHz - 750 KHz)
LM20154	4A, SYNCOUT
LM20242	36V, 2A Adjustable Frequency (250 KHz - 750 KHz)

Additional Resources

Design Tools (see below)

Application Notes (see below)

Block Diagram

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Block Diagram

Datasheet

RoHS Compliance Information	Size in Kbytes	Date
LM20123 3A, 1.5MHz PowerWise ® Synchronous Buck Regulator	584 Kbytes	16-Jan-08	View Online Download
LM20123 3A, 1.5MHz PowerWise ® Synchronous Buck Regulator (Japanese)	819 Kbytes

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Package Availability, Models, Samples & Pricing

Part Number

Package

Factory Lead Time

Models

Samples &
Electronic
Orders

Budgetary Pricing

Std
Pack
Size

Package
Marking
Format

Type

Pins

Spec.

MSL
Rating

Peak
Reflow

RoHS
Report

CAD
Symbols

Weeks

Qty

$US each

LM20123EVAL

3A, 1.5MHz PowerWise ® Synchronous Buck Regulator

Full production

N/A

$40.00

8 weeks

N/A

LM20123MH

TSSOP EXP PAD

NOPB

260

RoHS

Download

Full production

N/A

1K+

$2.30

rail
of
92

NSUZXYTT
20123
MH

6 weeks

N/A

LM20123MHE

TSSOP EXP PAD

NOPB

260

RoHS

Download

Full production

N/A

500+

$2.58

reel
of
250

NSUZXYTT
20123
MH

6 weeks

N/A

LM20123MHX

TSSOP EXP PAD

NOPB

260

RoHS

Download

Full production

N/A

1K+

$2.30

reel
of
2500

NSUZXYTT
20123
MH

6 weeks

N/A

General Description

The LM20123 is a full featured 1.5 MHz synchronous buck regulator capable of delivering up to 3A of continuous output current. The current mode control loop can be compensated to be stable with virtually any type of output capacitor. For most cases, compensating the device only requires two external components, providing maximum flexibility and ease of use. The device is optimized to work over the input voltage range of 2.95V to 5.5V making it suited for a wide variety of low voltage systems.

The device features internal over voltage protection (OVP) and over current protection (OCP) circuits for increased system reliability. A precision enable pin and integrated UVLO allows the turn on of the device to be tightly controlled and sequenced. Start-up inrush currents are limited by both an internally fixed and externally adjustable Soft-Start circuit. Fault detection and supply sequencing is possible with the integrated power good circuit.

The LM20123 is designed to work well in multi-rail power supply architectures. The output voltage of the device can be configured to track a higher voltage rail using the SS/TRK pin. If the output of the LM20123 is pre-biased at startup it will not sink current to pull the output low until the internal soft-start ramp exceeds the voltage at the feedback pin.

The LM20123 is offered in a 16-pin eTSSOP package with an exposed pad that can be soldered to the PCB, eliminating the need for bulky heatsinks.

Reliability Metrics

Part Number	Process	EFR Reject	EFR Sample Size	PPM *	LTA Rejects	LTA Device Hours	FITS	MTTF (Hours)
LM20123MH	CMOS7	0	13906	0	0	862500	5	244736730
LM20123MHE	CMOS7	0	13906	0	0	862500	5	244736730
LM20123MHX	CMOS7	0	13906	0	0	862500	5	244736730

Note: The Early Failure Rates were calculated as point estimates. The Long Term Failure Rates were calculated at 60% confidence using the Arrhenius equation at 0.7eV activation energy and derating the assumed stress temperature of 150°C to an application temperature of 55°C.

For more information on Reliability Metrics, please click here.

Design Tools

Title	Size in Kbytes	Date
Current Mode Modeling - Reference Guide	1372 Kbytes	1-Aug-2007	View Online	Download
Understanding and Applying Current-Mode Control Theory	427 Kbytes	8-Jan-2008	View Online	Download
Download LM20123 Design Spreadsheet			View
Reducing Buck Converter Input Capacitance through Multi-Phasing and Clock Synchronization			View
Benefits of Non-Linear Slope Compensation in Current Mode Control Switch Mode Powers - Part One			View
Benefits of Non-Linear Slope Compensation in Current Mode Control Switch Mode Powers - Part Two			View

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Application Notes

Title	Size in Kbytes	Date
AN-1686: Application Note 1686 LM20123 Evaluation Board	405 Kbytes	30-Oct-07	Download
AN-1686 (Japanese): Application Note 1686 LM20123 Evaluation Board	827 Kbytes
AN-1747: Application Note 1747 3A LM20k Reference Designs	227 Kbytes	9-Nov-07	Download

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More Application Notes

Title	Size in Kbytes	Date
AN-1751: Application Note 1751 4A LM20k Reference Designs	206 Kbytes	9-Nov-07	Download
AN-1752: Application Note 1752 5A LM20k Reference Designs	174 Kbytes	13-Nov-07	Download
AN-1654: Application Note 1654 LM20124 Evaluation Board	804 Kbytes	30-Oct-07	Download
AN-1654 (Japanese): Application Note 1654 LM20124 Evaluation Board	509 Kbytes
AN-1687: Application Note 1687 LM20125 Evaluation Board	816 Kbytes	30-Oct-07	Download
AN-1687 (Japanese): Application Note 1687 LM20125 Evaluation Board	991 Kbytes

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[Information as of 7-Jan-2009]