Features • 4.5V to 36V input voltage range • 3A output current, 5.2A peak current • 130 mΩ/110 mΩ integrated power MOSFETs • 94% peak efficiency with synchronous rectification • 1.5% feedback voltage accuracy • Current mode control, selectable compensation • Oscillator synchronization from 250kHz to 1.5MHz • Adjustable output voltage down to 0.8V • Compatible with pre-biased loads • Programmable soft-start with external capacitor • Precision enable pin with hysteresis • OVP, UVLO inputs and PGOOD output • Internally protected with peak current limit, thermal shutdown and restart • Accurate current limit minimizes inductor size • Non-linear current mode slope compensation • eTSSOP-20 exposed pad package Description The LM20333 is a full featured synchronous buck regulator capable of delivering up to 3A of load current. The current mode control loop is externally compensated with only two components, offering both high performance and ease of use. The device is optimized to work over the input voltage range of 4.5V to 36V making it well suited for high 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. Startup inrush currents are limited by both an internally fixed and externally adjustable soft-start circuit. Fault detection and supply sequencing are possible with the integrated power good (PGOOD) circuit. The LM20333 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 LM20333 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 switching frequency of the LM20333 can be synchronized to an external clock by use of the SYNC pin. The SYNC pin is capable of synchronizing to input signals ranging from 250 kHz to 1.5 MHz. The LM20333 is offered in an exposed pad 20-pin eTSSOP package 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 4.5V to 36V bus • High Performance DSPs, FPGAs, ASICs and Microprocessors • Communications Infrastructure, Automotive

LM20333   4.50 <= V in Lower  V   <= V in Upper  V   <= 36.00 V out 0.80 <=  V <= 32.00 I out    A <= 3.00 Ambient Temperature  °C <= 100 What are WEBENCH® tools? MY BRIEFCASE                                       Click any "Briefcase" icon to add an item

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

Datasheet

Title		Size	Date	Other Language
	LM20333 36V, 3A Synchronous Buck Regulator with Frequency Synchronization	525 Kbytes	20-Jan-09

Featured Application Notes

Title		Size	Date	Other Language
	AN-1791: Application Note 1791 LM20333 Evaluation Board	865 Kbytes	1-Oct-08

More Application Notes

Title		Size	Date	Other Language
	AN-1745: Application Note 1745 Powering FPGAs Using LM201xx PowerWise® Synchronous Buck Regulators	117 Kbytes	29-Oct-07	日本語 中文

Design Tools

Title	Size	Date
Download LM20333 Calculator spreadsheet	1040 Kbytes	2-Jun-2008

Reliability Metrics

Part Number	Process	EFR Reject	EFR Sample Size	PPM	LTA Rejects	LTA Device Hours	FITS	MTTF (Hours)
LM20333MH	ABCD150	0	34175	0	0	4234000	1	1201409060
LM20333MHE	ABCD150	0	34175	0	0	4234000	1	1201409060
LM20333MHX	ABCD150	0	34175	0	0	4234000	1	1201409060

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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