Datasheet LM2734 (Texas Instruments)

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LM2734
SNVS288J – SEPTEMBER 2004 – REVISED DECEMBER 2014
LM2734 Thin SOT 1-A Load Step-Down DC-DC Regulator 1 Features 3 Description
The LM2734 regulator is a monolithic, high- • Thin SOT-6 Package 1 frequency, PWM step-down DC-DC converter in a 6- • 3.0-V to 20-V Input Voltage Range pin Thin SOT package. The device provides all the • 0.8-V to 18-V Output Voltage Range active functions to provide local DC-DC conversion • 1-A Output Current with fast transient response and accurate regulation in the smallest possible PCB area. • 550-kHz (LM2734Y) and 1.6-MHz (LM2734X) Switching Frequencies With a minimum of external components and online design support through WEBENCH, the LM2734 • 300-mΩ NMOS Switch regulator is easy to use. The ability to drive 1-A loads • 30-nA Shutdown Current with an internal 300-mΩ NMOS switch using state-of- • 0.8-V, 2% Internal Voltage Reference the-art 0.5-µm BiCMOS technology results in the best • Internal Soft-Start power density available. The world-class control circuitry allows for on-times as low as 13 ns, thus • Current-Mode, PWM Operation supporting exceptionally high-frequency conversion • WEBENCH® Online Design Tool over the entire 3-V to 20-V input operating range • Thermal Shutdown down to the minimum output voltage of 0.8 V. Switching frequency is internally set to 550 kHz • LM2734XQ and LM2734YQ are AEC-Q100 Grade (LM2734Y) or 1.6 MHz (LM2734X), allowing the use 1 Qualified and are Manufactured on an of extremely small surface-mount inductors and chip Automotive Grade Flow. capacitors. Even though the operating frequencies are very high, efficiencies up to 90% are easy to
2 Applications
achieve. External shutdown is included, featuring an • Local Point-of-Load Regulation ultra-low standby current of 30 nA. • Core Power in HDDs The LM2734 regulator uses current-mode control and internal compensation to provide high-performance • Set-Top Boxes regulation over a wide range of operating conditions. • Battery-Powered Devices Additional features include internal soft-start circuitry • USB Powered Devices to reduce inrush current, pulse-by-pulse current limit, • DSL Modems thermal shutdown, and output overvoltage protection. • Notebook Computers
Device Information(1)
• Automotive
PART NUMBER PACKAGE BODY SIZE (NOM)
LM2734 SOT (6) 2.90 mm x 1.60 mm (1) For all available packages, see the orderable addendum at the end of the datasheet.
Typical Application Circuit Efficiency vs Load Current VIN = 5 V, VOUT = 3.3 V
D2 VIN VIN BOOST C3 C1 L1 SW VOUT
LM2734
ON D1 C2 EN OFF R1 FB GND R2 1 An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications, intellectual property matters and other important disclaimers. PRODUCTION DATA. Document Outline 1 Features 2 Applications 3 Description Table of Contents 4 Revision History 5 Pin Configuration and Functions 6 Specifications 6.1 Absolute Maximum Ratings 6.2 ESD Ratings 6.3 Recommended Operating Conditions 6.4 Thermal Information 6.5 Electrical Characteristics 6.6 Typical Performance Characteristics 7 Detailed Description 7.1 Overview 7.2 Functional Block Diagram 7.3 Feature Description 7.3.1 Output Overvoltage Protection 7.3.2 Undervoltage Lockout 7.3.3 Current Limit 7.3.4 Thermal Shutdown 7.4 Device Functional Modes 7.4.1 Enable Pin / Shutdown Mode 7.4.2 Soft-Start 8 Application and Implementation 8.1 Application Information 8.1.1 Boost Function 8.2 Typical Applications 8.2.1 LM2734X (1.6 MHz) VBOOST Derived from VIN 5V to 1.5 V/1 A 8.2.1.1 Design Requirements 8.2.1.2 Detailed Design Procedure 8.2.1.3 Application Curves 8.2.2 LM2734X (1.6 MHz) VBOOST Derived from VOUT 12 V to 3.3 V /1 A 8.2.2.1 Design Requirements 8.2.2.2 Detailed Design Procedure 8.2.2.3 Application Curves 8.2.3 LM2734X (1.6 MHz) VBOOST Derived from VSHUNT 18 V to 1.5 V /1 A 8.2.3.1 Design Requirements 8.2.3.2 Detailed Design Procedure 8.2.3.3 Application Curves 8.2.4 LM2734X (1.6 MHz) VBOOST Derived from Series Zener Diode (VIN) 15 V to 1.5 V / 1 A 8.2.4.1 Design Requirements 8.2.4.2 Detailed Design Procedure 8.2.4.3 Application Curves 8.2.5 LM2734X (1.6 MHz) VBOOST Derived from Series Zener Diode (VOUT) 15 V to 9 V /1 A 8.2.5.1 Design Requirements 8.2.5.2 Detailed Design Procedure 8.2.5.3 Application Curves 8.2.6 LM2734Y (550 kHz) VBOOST Derived from VIN 5 V to 1.5 V / 1 A 8.2.6.1 Design Requirements 8.2.6.2 Detailed Design Procedure 8.2.6.3 Application Curves 8.2.7 LM2734Y (550 kHz) VBOOST Derived from VOUT 12 V to 3.3 V / 1 A 8.2.7.1 Design Requirements 8.2.7.2 Detailed Design Procedure 8.2.7.3 Application Curves 8.2.8 LM2734Y (550 kHz) VBOOST Derived from VSHUNT 18 V to 1.5 V / 1 A 8.2.8.1 Design Requirements 8.2.8.2 Detailed Design Procedure 8.2.8.3 Application Curves 8.2.9 LM2734Y (550 kHz) VBOOST Derived from Series Zener Diode (VIN) 15 V to 1.5 V / 1 A 8.2.9.1 Design Requirements 8.2.9.2 Detailed Design Procedure 8.2.9.3 Application Curves 8.2.10 LM2734Y (550 kHz) VBOOST Derived from Series Zener Diode (VOUT) 15 V to 9 V / 1 A 8.2.10.1 Design Requirements 8.2.10.2 Detailed Design Procedure 8.2.10.3 Application Curves 9 Power Supply Recommendations 10 Layout 10.1 Layout Guidelines 10.2 Layout Example 11 Device and Documentation Support 11.1 Third-Party Products Disclaimer 11.2 Trademarks 11.3 Electrostatic Discharge Caution 11.4 Glossary 12 Mechanical, Packaging, and Orderable Information