LTC4425 - Linear SuperCap Charger with Current-Limited Ideal Diode and V/I Monitor

Features

  • 50mΩ Ideal Diode from VIN to VOUT
  • Smart Charge Current Profile Limits Inrush Current
  • Internal Cell Balancer (No External Resistors)
  • Programmable Output Voltage (LDO Mode)
  • Programmable VIN to VOUT Current Limit
  • Continuous Monitoring of VIN to VOUT Current via PROG Pin
  • Low Quiescent Current: 20μA
  • VIN Power Fail, PGOOD Indicator
  • 2.45V/2.7V Cell Protection Shunts
    (4.9V/5.4V SuperCap Max Top-Off Voltage)
  • 3A Peak Current Limit, Thermal Limiting
  • Tiny Application Circuit, 3mm × 3mm × 0.75mm DFN and 12-Lead MSOP Packages
Designed for Automotive and Transportation Applications
AEC-Q100 generic family data available for specific packages


Typical Application

LTC4425 Typical Application
LTC4425 Typical Application

Description

The LTC4425 is a constant-current/constant-voltage linear charger designed to charge a 2-cell supercap stack from either a Li-Ion/Polymer battery, a USB port, or a 2.7V to 5.5V current-limited supply. The part operates as an ideal diode with an extremely low 50mΩ on-resistance making it suitable for high peak-power/low average power applications. The LTC4425 charges the output capacitors to an externally programmed output voltage in LDO mode at a constant charge current, or to VIN in normal mode with a smart charge current profile to limit the inrush current until the VIN to VOUT differential is less than 250mV. In addition the LTC4425 can be set to clamp the output voltage to 4.9V or 5.4V.

Charge current (VOUT current limit) is programmed by connecting a resistor between PROG and GND. The voltage on the PROG pin represents the current fl owing from VIN to VOUT for current monitoring. An internal active balancing circuit maintains equal voltages across each supercapacitor and clamps the peak voltage across each cell to a pin-selectable maximum value. The LTC4425 operates at a very low 20μA quiescent current (shutdown current <3μA) and is available in a low profile 12-pin 3mm × 3mm DFN or a 12-lead MSOP package.

Packaging

CAD Symbols and Footprints: The downloadable Zip file below contains the schematic symbol and PCB footprints.

For complete and up to date package information and drawings, please refer to our packaging page

Part Number Package Code Temp Package
Drawing
RoHS
LTC4425EDD#PBF 3x3 DFN-12 DD E 05-08-1725 Yes
LTC4425EDD#TRPBF 3x3 DFN-12 DD E 05-08-1725 Yes
LTC4425EMSE#PBF MS-12E MSE E 05-08-1666 Yes
LTC4425EMSE#TRPBF MS-12E MSE E 05-08-1666 Yes
LTC4425IDD#PBF 3x3 DFN-12 DD I 05-08-1725 Yes
LTC4425IDD#TRPBF 3x3 DFN-12 DD I 05-08-1725 Yes
LTC4425IMSE#PBF MS-12E MSE I 05-08-1666 Yes
LTC4425IMSE#TRPBF MS-12E MSE I 05-08-1666 Yes


LTC4425 Package Drawing
LTC4425 Package Drawing

Order Info

  • Part numbers ending in PBF are lead free. Solder plated terminal finish (SnPb) versions are non-standard and special terms and conditions and pricing applies if available. Please contact LTC marketing for information.
  • Part numbers containing TR or TRM are shipped in tape and reel or 500 unit mini tape and reel, respectively
  • Please refer to our general ordering information or the product datasheet for more details

Package Variations and Pricing

Part Number Package Temp Price
(1-99)
Price
(1k)*
RoHS
LTC4425EDD#PBF 3x3 DFN-12 E $3.22 $2.25 Yes
LTC4425EDD#TRPBF 3x3 DFN-12 E $2.31 Yes
LTC4425EMSE#PBF MS-12E E $3.36 $2.35 Yes
LTC4425EMSE#TRPBF MS-12E E $2.41 Yes
LTC4425IDD#PBF 3x3 DFN-12 I $3.71 $2.60 Yes
LTC4425IDD#TRPBF 3x3 DFN-12 I $2.66 Yes
LTC4425IMSE#PBF MS-12E I $3.86 $2.70 Yes
LTC4425IMSE#TRPBF MS-12E I $2.76 Yes
Buy NowRequest Samples
* The USA list pricing shown is for BUDGETARY USE ONLY, shown in United States dollars (FOB USA per unit for the stated volume), and is subject to change. International prices may differ due to local duties, taxes, fees and exchange rates. For volume-specific price or delivery quotes, please contact your local Linear Technology sales office or authorized distributor.

Demo Boards

Linear Technology offers many demo boards free of charge to qualified customers. Contact your local sales office or distributor to inquire about a demo board. Certain demo boards are also available for sale via credit card on this website. Demo boards are for evaluation purposes only. It remains the customer’s responsibility to verify proper and reliable operation in the actual end application.

Part Number Description Price Documentation
DC1589A LTC4425EDD Demo Board | Linear SuperCap Charger with Current-Limited Ideal Diode and V/I Monitor $100.00
Buy Now
Click here to view our complete list of demo boards

Designed for Automotive and Transportation Applications

Please contact your local sales representative for more information regarding reliability reports and AEC-Q100 data or to inquire about parts that are not included. For more information, view our Automotive and Transportation page

Part Number Package Temp Price
(1-99)
Price
(1k)*
RoHS
LTC4425IDD#PBF 3x3 DFN-12 I $3.71 $2.60 Yes
LTC4425IDD#TRPBF 3x3 DFN-12 I $2.66 Yes
LTC4425IMSE#PBF MS-12E I $3.86 $2.70 Yes
LTC4425IMSE#TRPBF MS-12E I $2.76 Yes
Buy NowRequest Samples
* The USA list pricing shown is for BUDGETARY USE ONLY, shown in United States dollars (FOB USA per unit for the stated volume), and is subject to change. International prices may differ due to local duties, taxes, fees and exchange rates. For volume-specific price or delivery quotes, please contact your local Linear Technology sales office or authorized distributor.

Applications

  • High Peak Power Battery/USB Powered Equipment
  • Industrial PDAs
  • Portable Instruments/Monitoring Equipment
  • Power Meters, SuperCap Backup Circuits
  • PC Card/USB Modems

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