LTC4235 - Dual 12V Ideal Diode-OR and Single Hot Swap Controller with Current Monitor

Features

  • Ideal Diode-OR and Inrush Current Control for Redundant Supplies
  • Low Loss Replacement for Power Schottky Diodes
  • Enables Safe Board Insertion into a Live Backplane
  • 9V to 14V Operation
  • Current Monitor Output
  • Controls N-Channel MOSFETs
  • Limits Peak Fault Current in ≤ 1μs
  • Adjustable Current Limit with Foldback
  • Adjustable Current Limit Fault Delay
  • 0.5μs Ideal Diode Turn-On and Turn-Off Time
  • Smooth Switchover without Oscillation
  • Fault and Power Good Outputs
  • LTC4235-1: Latch Off After Fault
  • LTC4235-2: Automatic Retry After Fault
  • 20-Pin 4mm x 5mm QFN Package

Typical Application

LTC4235 Typical Application
LTC4235 Typical Application

Description

The LTC®4235 offers ideal diode-OR and Hot SwapTM functions for two 12V power rails by controlling external N-channel MOSFETs. MOSFETs acting as ideal diodes replace two high power Schottky diodes and the associated heat sinks, saving power and board area. A Hot Swap control MOSFET allows a board to be safely inserted and removed from a live backplane by limiting inrush current. The supply output is also protected against short-circuit faults with a foldback current limit and circuit breaker.

The LTC4235 regulates the forward voltage drop across the MOSFETs to ensure smooth current transfer from one supply to the other without oscillation. The ideal diodes turn on quickly to reduce the load voltage droop during supply switchover. If the input supply fails or is shorted, a fast turn-off minimizes reverse-current transients.

A current sense amplifier translates the voltage across the sense resistor to a ground referenced signal. The LTC4235 allows turn-on/off control, and reports fault and power good status for the supply.

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
LTC4235CUFD-1#PBF 4x5 QFN-20 UFD C 05-08-1711 Yes
LTC4235CUFD-1#TRPBF 4x5 QFN-20 UFD C 05-08-1711 Yes
LTC4235CUFD-2#PBF 4x5 QFN-20 UFD C 05-08-1711 Yes
LTC4235CUFD-2#TRPBF 4x5 QFN-20 UFD C 05-08-1711 Yes
LTC4235IUFD-1#PBF 4x5 QFN-20 UFD I 05-08-1711 Yes
LTC4235IUFD-1#TRPBF 4x5 QFN-20 UFD I 05-08-1711 Yes
LTC4235IUFD-2#PBF 4x5 QFN-20 UFD I 05-08-1711 Yes
LTC4235IUFD-2#TRPBF 4x5 QFN-20 UFD I 05-08-1711 Yes


LTC4235 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
LTC4235CUFD-1#PBF 4x5 QFN-20 C $5.64 $3.95 Yes
LTC4235CUFD-1#TRPBF 4x5 QFN-20 C $4.01 Yes
LTC4235CUFD-2#PBF 4x5 QFN-20 C $5.64 $3.95 Yes
LTC4235CUFD-2#TRPBF 4x5 QFN-20 C $4.01 Yes
LTC4235IUFD-1#PBF 4x5 QFN-20 I $6.21 $4.35 Yes
LTC4235IUFD-1#TRPBF 4x5 QFN-20 I $4.41 Yes
LTC4235IUFD-2#PBF 4x5 QFN-20 I $6.21 $4.35 Yes
LTC4235IUFD-2#TRPBF 4x5 QFN-20 I $4.41 Yes
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* 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
DC2315A-A LTC4235-1 Demo Board | Dual 12V Ideal Diode-OR & Single Hot Swap Controller with Current Monitor, Latch-Off $75.00
DC2315A-B LTC4235-2 Demo Board | Dual 12V Ideal Diode-OR & Single Hot Swap Controller with Current Monitor, Auto-Retry $75.00
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Click here to view our complete list of demo boards

Applications

  • Redundant Power Supplies
  • High Availability Systems and Servers
  • Telecom and Network Infrastructure

Product Notifications

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Design Tools

LTspice

LTspice® software is a powerful, fast and free simulation tool, schematic capture and waveform viewer with enhancements and models for improving the simulation of switching regulators. Click here to download LTspice

Models for the following parts are available in LTspice:
LTC4235-1
LTC4235-2

Technical Support