ADI LTC4418IUF#PBF

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.

• 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

• Industrial Handheld Instruments
• High Availability Systems
• Battery Backup Systems
• Servers and Computer Peripherals