LTC1538-AUX

PRODUCTION

Dual High Efficiency, Low Noise, Synchronous Step-Down Switching Regulators

Part Models: 4
1ku List Price: Starting From $8.74

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Overview

Maintains Constant Frequency at Low Output Currents
Dual N-Channel MOSFET Synchronous Drive
Programmable Fixed Frequency (PLL Lockable)
Wide V_IN Range: 3.5V to 36V Operation
Ultrahigh Efficiency
Very Low Dropout Operation: 99% Duty Cycle
Low Dropout, 0.5A Linear Regulator for VPP
Generation or Low Noise Audio Supply
Built-In Power-On Reset Timer
Programmable Soft Start
Low-Battery Detector
Remote Output Voltage Sense
Foldback Current Limiting (Optional)
Pin Selectable Output Voltage
5V Standby Regulator Active in Shutdown: I_Q < 200 µA
Output Voltages from 1.19V to 9V
Available in 28- and 36-Lead SSOP Packages

The LTC1538-AUX/LTC1539 are dual, synchronous step-down switching regulator controllers which drive external N-channel power MOSFETs in a phase-lockable fixed frequency architecture. The Adaptive Power^TM output stage selectively drives two N-channel MOSFETs at frequencies up to 400kHz while reducing switching losses to maintain high efficiencies at low output currents.

An auxiliary 0.5A linear regulator using an external PNP pass device provides a low noise, low dropout voltage source. A secondary winding feedback control pin (SFB1) guarantees regulation regardless of load on the main output by forcing continuous operation.

A 5V/20mA regulator, internal 1.19V reference and an uncommitted comparator remain active when both controllers are shut down. A power-on reset timer (POR) is included which generates a signal delayed by 65536/f_CLK (typ 300ms) after the controller’s output is within 5% of the regulated first voltage. Internal resistive dividers provide pin selectable output voltages with remote sense capability on one of the two outputs.

The operating current levels are user-programmable via external current sense resistors. Wide input supply range allows operation from 3.5V to 30V (36V maximum).

Applications

Notebook and Palmtop Computers, PDAs
Portable Instruments
Battery-Operated Devices
DC Power Distribution Systems

Part Models: 4
1ku List Price: Starting From $8.74

Documentation

ADI has always placed the highest emphasis on delivering products that meet the maximum levels of quality and reliability. We achieve this by incorporating quality and reliability checks in every scope of product and process design, and in the manufacturing process as well. "Zero defects" for shipped products is always our goal. View our quality and reliability program and certifications for more information.

Part Model	Pin/Package Drawing	Documentation	CAD Symbols, Footprints, and 3D Models
LTC1538CG-AUX#PBF	28-Lead SSOP	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
LTC1538CG-AUX#TRPBF	28-Lead SSOP	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
LTC1538IG-AUX#PBF	28-Lead SSOP	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
LTC1538IG-AUX#TRPBF	28-Lead SSOP	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys

Part Models	Product Lifecycle	PCN

Aug 6, 2022 - 22_0171 Laser Top Mark Conversion for SSOP Packages Assembled in PNG
		PCN22_0171_Form Material_Report Delta Qualification Matrix
LTC1538CG-AUX#PBF	PRODUCTION
LTC1538CG-AUX#TRPBF	PRODUCTION
LTC1538IG-AUX#PBF	PRODUCTION
LTC1538IG-AUX#TRPBF	PRODUCTION

This is the most up-to-date revision of the Data Sheet.

Software Resources

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Tools & Simulations

LTspice 1

LTC1538-AUX - Step-Down (Buck) Regulators

Models for the following parts are available in LTspice:

LTC1538-AUX

LTspice® is a powerful, fast and free simulation software, schematic capture and waveform viewer with enhancements and models for improving the simulation of analog circuits.