LM1771 Controller Datasheet

LM1771 Datasheet, PDF, Equivalent


Part Number

LM1771

Description

Low-Voltage Synchronous Buck Controller

Manufacture

etcTI

Total Page 30 Pages
Datasheet
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LM1771
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LM1771
SNVS446D – JUNE 2006 – REVISED JANUARY 2016
LM1771 Low-Voltage Synchronous Buck Controller With Precision Enable and No
External Compensation
1 Features
1 Input Voltage Range of 2.8 V to 5.5 V
• 0.8-V Reference Voltage
• Precision Enable
• No Compensation Required
• Constant Frequency Across Input Range
• Low Quiescent Current of 400 µA
• Internal Soft-Start
• Short Circuit Protection
• 6-Pin WSON Package and 8-Pin VSSOP Package
2 Applications
• Simple-to-Design, High-Efficiency, Step-Down
Switching Regulators
• FPGAs, DSPs, and ASIC Power Supplies
• Set-Top Boxes
• Cable Modems
• Printers
• Digital Video Recorders
• Servers
• Graphic Cards
3 Description
The LM1771 device is an efficient synchronous buck
switching controller with a precision enable requiring
no external compensation. The constant ON-time
control scheme provides a simple design free of
compensation components, allowing minimal
component count and board space. The precision
enable pin allows flexibility in sequencing multiple
rails and setting UVLO. The LM1771 also
incorporates a unique input feedforward to maintain a
constant frequency independent of the input voltage.
The LM1771 is optimized for a low-voltage input
range of 2.8 V to 5.5 V and can provide an adjustable
output as low as 0.8 V. Driving an external high-side
PFET and low-side NFET, it can provide efficiencies
as high as 95%.
Three versions of the LM1771 are available
depending on the switching frequency desired for the
application. Nominal switching frequencies are in the
range of 100 kHz to 1000 kHz.
Device Information(1)
PART NUMBER
PACKAGE
BODY SIZE (NOM)
LM1771
WSON (6)
VSSOP (8)
3.00 mm × 3.00 mm
3.00 mm × 3.00 mm
(1) For all available packages, see the orderable addendum at
the end of the data sheet.
Typical Application Circuit
VIN
VIN
EN EN
HG
LM1771
LG
VOUT
GND
FB
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.

LM1771
LM1771
SNVS446D – JUNE 2006 – REVISED JANUARY 2016
www.ti.com
Table of Contents
1 Features .................................................................. 1
2 Applications ........................................................... 1
3 Description ............................................................. 1
4 Revision History..................................................... 2
5 Pin Configuration and Functions ......................... 3
6 Specifications......................................................... 4
6.1 Absolute Maximum Ratings ..................................... 4
6.2 ESD Ratings.............................................................. 4
6.3 Recommended Operating Conditions....................... 4
6.4 Thermal Information .................................................. 4
6.5 Electrical Characteristics........................................... 5
6.6 Typical Characteristics .............................................. 6
7 Detailed Description .............................................. 9
7.1 Overview ................................................................... 9
7.2 Functional Block Diagram ......................................... 9
7.3 Feature Description................................................. 10
7.4 Device Functional Modes........................................ 12
8 Application and Implementation ........................ 13
8.1 Application Information............................................ 13
8.2 Typical Applications ................................................ 13
9 Power Supply Recommendations...................... 20
10 Layout................................................................... 21
10.1 Layout Guidelines ................................................. 21
10.2 Layout Examples................................................... 21
10.3 Thermal Considerations ........................................ 22
11 Device and Documentation Support ................. 23
11.1 Device Support .................................................... 23
11.2 Documentation Support ........................................ 23
11.3 Community Resources.......................................... 23
11.4 Trademarks ........................................................... 23
11.5 Electrostatic Discharge Caution ............................ 23
11.6 Glossary ................................................................ 23
12 Mechanical, Packaging, and Orderable
Information ........................................................... 23
4 Revision History
NOTE: Page numbers for previous revisions may differ from page numbers in the current version.
Changes from Revision C (April 2013) to Revision D
Page
• Added ESD Ratings table, Feature Description section, Device Functional Modes, Application and Implementation
section, Power Supply Recommendations section, Layout section, Device and Documentation Support section, and
Mechanical, Packaging, and Orderable Information section. ................................................................................................ 1
Changes from Revision B (April 2013) to Revision C
Page
• Changed layout of National Data Sheet to TI format ........................................................................................................... 22
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Copyright © 2006–2016, Texas Instruments Incorporated


Features Product Folder Sample & Buy Technical Documents Tools & Software Support & Community LM1771 SNVS446D – JUNE 200 6 – REVISED JANUARY 2016 LM1771 Low-V oltage Synchronous Buck Controller With Precision Enable and No External Compe nsation 1 Features •1 Input Voltage Range of 2.8 V to 5.5 V • 0.8-V Refer ence Voltage • Precision Enable • N o Compensation Required • Constant Fr equency Across Input Range • Low Quie scent Current of 400 µA • Internal S oft-Start • Short Circuit Protection • 6-Pin WSON Package and 8-Pin VSSOP Package 2 Applications • Simple-to-De sign, High-Efficiency, Step-Down Switch ing Regulators • FPGAs, DSPs, and ASI C Power Supplies • Set-Top Boxes • Cable Modems • Printers • Digital V ideo Recorders • Servers • Graphic Cards 3 Description The LM1771 device is an efficient synchronous buck switch ing controller with a precision enable requiring no external compensation. The constant ON-time control scheme provides a simple design free of compensation components, allowing mi.
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