Features • Input voltage range 2.95V to 5.5V • Accurate current limit minimizes inductor size • 97% efficiency with 500 kHz 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 Description The LM20125 is a full featured 500 kHz synchronous buck regulator capable of delivering up to 5A 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 LM20125 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 LM20125 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 LM20125 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. 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

LM20125   2.95 <= V in Lower  V   <= V in Upper  V   <= 5.50 V out 0.80 <=  V <= 4.00 I out    A <= 5.00 Ambient Temperature  °C <= 100 What are WEBENCH® tools? Also Recommended LM20123▲ 3A, 1.5 MHz Switching Frequency LM20124▲ 4A, 1 MHz 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) MY BRIEFCASE                                       Click any "Briefcase" icon to add an item

Typical Application click for larger image	Block Diagram click for larger image Block Diagram
Typical Performance click for larger image

Datasheet

Title		Size	Date	Other Language
	LM20125 5A, 500kHz PowerWise ® Synchronous Buck Regulator	583 Kbytes	16-Jan-08	日本語

Featured Application Notes

Title		Size	Date	Other Language
	AN-1687: Application Note 1687 LM20125 Evaluation Board	816 Kbytes	30-Oct-07	日本語
	AN-1752: Application Note 1752 5A LM20k Reference Designs	174 Kbytes	13-Nov-07

More Application Notes

Title		Size	Date	Other Language
	AN-1747: Application Note 1747 3A LM20k Reference Designs	227 Kbytes	9-Nov-07
	AN-1751: Application Note 1751 4A LM20k Reference Designs	206 Kbytes	9-Nov-07
	AN-1654: Application Note 1654 LM20124 Evaluation Board	804 Kbytes	30-Oct-07	日本語
	AN-1686: Application Note 1686 LM20123 Evaluation Board	405 Kbytes	30-Oct-07	日本語

Design Tools

Title	Size	Date
Current Mode Modeling - Reference Guide	1372 Kbytes	1-Aug-2007
Understanding and Applying Current-Mode Control Theory	427 Kbytes	8-Jan-2008
Download LM20125 Design Spreadsheet
Article - Reducing Buck Converter Input Capacitance through Multi-Phasing and Clock Synchronization

Reliability Metrics

Part Number	Process	EFR Reject	EFR Sample Size	PPM	LTA Rejects	LTA Device Hours	FITS	MTTF (Hours)
LM20125MH	CMOS7	0	18406	0	0	1089000	4	309006723
LM20125MHE	CMOS7	0	18406	0	0	1089000	4	309006723
LM20125MHX	CMOS7	0	18406	0	0	1089000	4	309006723

Note: The Early Failure Rates (EFR) were calculated as point estimate PPM based on rejects and sample size for EFR. 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.

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