Features and Benefits
- Selects Highest Priority Supply from Two Inputs
- Blocks Reverse and Cross Conduction Currents
- Wide Operating Voltage Range: 2.5V to 40V
- –42V Protection Against Reverse Connection
- 60V Tolerant V1, V2 Inputs
- Adjustable Input Validation Time
- Fast Switchover Minimizes Output Voltage Droop
- Low 26µA Operating Current
- ±1.5% Input Overvoltage/Undervoltage Protection
- Adjustable Overvoltage/Undervoltage Hysteresis
- Cascadable for Additional Input Supplies
- 20-Lead 4mm × 4mm QFN Package
The LTC4418 connects one of two valid power supplies to a common output based on priority and validity. Priority is defined by pin assignment, with V1 assigned the higher priority and V2 the lower priority. A power supply is defined as valid when its voltage has been within its overvoltage (OV) and undervoltage (UV) window continuously for at least the configured validation time. If the highest priority valid input falls out of the OV/UV window, the channel is immediately disconnected and the other valid input is connected to the common output. Multiple LTC4418s, as well as triple channel LTC4417s, can be cascaded to provide switchover between more than two inputs.
The LTC4418 incorporates fast non-overlap switching circuitry to prevent both reverse and cross conduction while minimizing output droop. The gate driver includes a 6V clamp to protect external MOSFETs. A controlled soft-start feature minimizes start-up inrush current. Open drain VALID outputs indicate the input supplies have been within their OV/UV window for the duration of the validation time. The validation time can be disabled or adjusted using an external capacitor
- Industrial Handheld Instruments
- High Availability Systems
- Battery Backup Systems
- Servers and Computer Peripherals
Product Lifecycle Production
At least one model within this product family is in production and available for purchase. The product is appropriate for new designs but newer alternatives may exist.
Evaluation Kits (1)
Demonstration circuit 2707B uses the LTC®4418 to arbitrate between two input supply rails, selecting the highest priority, valid supply to power the load. The V1 rail is defined to have higher priority and the V2 rail has lower priority. Both rails have individual overvoltage and undervoltage comparators for setting valid window thresholds with external resistive dividers. If the highest priority rail voltage V1 falls out of the defined window (overvoltage or undervoltage), the V2 rail, if it is valid, is enabled and powers the load. Two or more LTC4418s can be cascaded to provide switchover between more than two rails.
Tools & Simulations
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.
Models for the following parts are available in LTspice:
Solutions Bulletins & Brochures (1)
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.
Sample & Buy
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 Analog Devices, Inc. sales office or authorized distributor. Pricing displayed for Evaluation Boards and Kits is based on 1-piece pricing.