LTC3355

RECOMMENDED FOR NEW DESIGNS

20V 1A Buck DC/DC with Integrated SCAP Charger and Backup Regulator

Part Models: 4
1ku List Price: Starting From $3.89

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Overview

V_IN Voltage Range: 3V to 20V
V_OUT Voltage Range: 2.7V to 5V
1A Current Mode Buck Main Regulator
5A Boost Backup Regulator Powered from Single Supercapacitor
Boost Regulator Operates Down to 0.5V for Maximum Utilization of Supercapacitor Energy
Programmable Supercapacitor Charge Current to 1A with Overvoltage Protection
Charger Supports Single Cell CC/CV Battery Charging
Programmable V_IN Current Limit
Programmable Boost Current Limit
V_IN Power Fail Indicator
V_CAP Power Good Indicator
V_OUT Power On Reset Output
Compact 20-Lead 4mm × 4mm QFN Package

The LTC3355 is a complete input power interrupt ride-through DC/DC system. The part charges a supercapacitor while delivering load current to V_OUT, and uses energy from the supercapacitor to provide continuous V_OUT backup power when V_IN power is lost. The LTC3355 contains a nonsynchronous constant frequency current mode monolithic 1A buck switching regulator to provide a 2.7V to 5V regulated output voltage from an input supply of up to 20V.

A 1A programmable CC/CV linear charger charges the supercapacitor from V_OUT. When the V_IN supply drops below the PFI threshold, the devices’s constant frequency nonsynchronous current mode 5A boost switching regulator delivers power from the supercapacitor to V_OUT. A thermal regulation loop maximizes charge current while limiting the die temperature to 110°C. The IC has boost, charger and V_IN programmable current limits. The LTC3355 is available in a 20-lead 4mm × 4mm QFN surface mount package.

Applications

Ride-Through “Dying Gasp” Supplies
Power Meters/Industrial Alarms/Solid State Drives

Part Models: 4
1ku List Price: Starting From $3.89

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
LTC3355EUF#PBF	20-Lead QFN (4mm x 4mm x 0.75mm w/ EP)	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
LTC3355EUF#TRPBF	20-Lead QFN (4mm x 4mm x 0.75mm w/ EP)	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
LTC3355IUF#PBF	20-Lead QFN (4mm x 4mm x 0.75mm w/ EP)	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
LTC3355IUF#TRPBF	20-Lead QFN (4mm x 4mm x 0.75mm w/ EP)	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys

Part Models	Product Lifecycle	PCN

Feb 20, 2022 - 21_0269 Addition of Alternate Assembly Site ASE Taiwan for Select LFCSP Products
		PCN21_0269_Form Material_Report Detailed Change Description Qualification Results Summary
LTC3355EUF#PBF	PRODUCTION
LTC3355EUF#TRPBF	PRODUCTION
LTC3355IUF#PBF	PRODUCTION
LTC3355IUF#TRPBF	PRODUCTION
Dec 3, 2020 - 20_0245 Notification of Wafer Fab Location Change for 0.6µm BICMOS Process Devices from ADI Milpitas (Hillview) to Vanguard Int. (Taiwan)
		PCN20_0245_Form Material_Report Delta Qualification Matrix Other Qualification Results Summary
LTC3355EUF#PBF	PRODUCTION
LTC3355EUF#TRPBF	PRODUCTION
LTC3355IUF#PBF	PRODUCTION
LTC3355IUF#TRPBF	PRODUCTION

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

Software Resources

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Hardware Ecosystem

Parts	Product Life Cycle	Description
Protection Switches & Controllers 1
LTC4353	RECOMMENDED FOR NEW DESIGNS	Dual Low Voltage Ideal Diode Controller

Parts	Product Life Cycle	Description
LTC3350	RECOMMENDED FOR NEW DESIGNS	High Current Supercapacitor Backup Controller and System Monitor

Tools & Simulations

LTspice

Models for the following parts are available in LTspice:

LTC3355

Software and Simulation 1

LTC3355 Backup Time Calculator

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.

Evaluation Kits

LTC3355EUF Demo Board | 12V to 4V/1A Buck Regulator + SCAP Charger & Backup Boost Regulator

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Product Details

Demonstration circuit 2040A is a 12V to 4V/1A regulator with an integrated supercap charger and backup boost regulator featuring the LTC3355EUF. The LTC3355 charges up a 3F supercapacitor from the output when the 12V input is available. When the 12V input fails, the backup boost regulator supplies the output until the energy in the supercapacitor is depleted. Figure 2 illustrates how long a 3F supercapacitor can provide a 4W output when the input power fails (~600ms).