LM1770 #9: 1.8V @ 2A, 3.3V in, (Page 17)

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.

This is another design utilizing small sized components chosen to fit on the LM1770 evaluation board PCB. A 6.2 µH inductor along with a 68 µF POSCAP capacitor are used to implement the output filter, and a 10 nF feed-forward capacitor is added to help improve stability.

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	1.8 V
Current Out	2 A
Voltage In	3.3 V
Efficiency @ Conditions	>90%, 3.3V in, 1.8V @ 300 mA ~ 1.1 A >86%, 3.3V in, 1.8V @ 0.3 ~ 2 A
Voltage Out Range
Features	Short Circuit Protection Soft Start
Switching Frequency	545 kHz
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	LM1770T
Date Created By Author
Date Added To Library	2011-03