LM1770 #3: 2.5V @ 3A, 5V in, (Page 7)

Summary

The controller utilizes a constant on-time control scheme which eliminates the need for external compensation components, allowing the power supply designer to minimize necessary board space and reduce costs.

The use of a small valued inductor (1.5 µH) is made possible by the high frequency operation. A 68 µF, low profile, POSCAP output capacitor is used, along with a 10 nF ceramic feed-forward capacitor, to ensure stability. The 500 ns LM1770 timing option allows for the 1.5 MHz switching frequency.

Specifications

Manufacturer Texas Instruments
Category AC/DC and DC/DC Conversion
Sub-Category DC/DC SMPS - Single Output
Eval Board Board not Stocked
Topology Step Down
Outputs and Type 1 Non-Isolated
Voltage Out: Factory Set 2.5 V
Current Out 3 A
Voltage In 5 V
Efficiency @ Conditions >84%, 5V in, 2.5V @ 0.8 ~ 3 A
Voltage Out Range
Features Short Circuit Protection
Soft Start
Switching Frequency 1.5 MHz
Standby Current [Typical]
Quiescent Current [Typical] 400 µA
Component Count + Extras 9 + 0
Internal Switch No
Design Author Texas Instruments
Application / Target Market Computers
DVD/Blu-ray Players
Point of Load (PoL)
Portable Devices
Set-Top Boxes
Telecom
USB Powered Devices
White Goods
Standby Current [Maximum]
Quiescent Current [Maximum] 600 µA
Main I.C. Base Part LM1770S
Date Created By Author
Date Added To Library 2020-05

Support Documents & Media

LM1770 - AN-1414 - Design Reference LM1770 - Datasheet AN-1149 - Layout Guidelines for SMPS AN-1197 - Selecting Inductors for Buck DC/DC

Media

LM1770_3__Schematic_Page_5_.JPG
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