LT8440

RECOMMENDED FOR NEW DESIGNS

LT8440

Power Conditioner for APL Field Devices

RECOMMENDED FOR NEW DESIGNS

Part Details

LT8440 Typical Application CIrcuit slide

Not the part you were looking for?

Go to Product Selection Table

View All Documentation

Ask a Question

Submit your question below and we will return the best answer from ADI’s knowledge database:

Other places you can find help

Support

Analog Devices Support Portal is a one-stop shop to answer all your ADI questions.

Visit the ADI Support Page

Ask the ADI community for help.

Ask the EngineerZone Community

FAQs

Sales & Ordering FAQs

Part Models 2

1ku List Price Starting From $2.85

Features

650mW Power Limit for Intrinsic Safety Thermal
Rating when Line Voltage ≤ 18.5V
35mA Current Limit if Line Voltage > 18.5V
55mA Current Limit for APL Class A Devices
Shunt Regulator for Mitigating Load Changes
Guaranteed 20mA Rectifier Current for Signal Integrity

Guaranteed to deliver full 500mW APL power to the load
6V to 36V Input Voltage
Integrated Current Sense Resistor
Polarity Insensitive Line Voltage Detectio
8-Lead SOIC Package with Exposed Pad

Additional Details

The LT8440 is a power conditioner for intrinsically safe, industrial ethernet ports in hazardous or explosive environments. The internal pass transistor is normally fully enhanced to deliver power to the load efficiently. In case of load circuit failures, the FET is modulated to limit the power to less than 650mW if line voltage ≤ 18.5V or less than 35mA if line voltage > 18.5V. The internal shunt transistor draws current parallel with the load up to the 500mW minimum guaranteed for Class A load power ports in compliance with Advanced Physical Layer (APL) standard or to 20mA minimum guaranteed if line voltage > 18.5V. The line voltage is sensed with two input pins that are insensitive to polarity, which can be connected in front of the port rectifier and incorporate the rectifier power consumption in the limitation of total power. The line current is measured as a voltage across the internal sense resistor, and the shunt current and the current limit are automatically adjusted for line voltage.

The LT8440 is packaged in an 8-lead SOIC with pin spacing that satisfies the device under coating specification so that shorts from pin to pin are countable faults when the circuit is examined for intrinsic safety at the highest levels of protection.

APPLICATIONS

Industrial Ethernet
 Advanced Physical Layer
 Current Limiting

View All Documentation

Ask a Question

Submit your question below and we will return the best answer from ADI’s knowledge database:

Other places you can find help

Support

Analog Devices Support Portal is a one-stop shop to answer all your ADI questions.

Visit the ADI Support Page

Ask the ADI community for help.

Ask the EngineerZone Community

FAQs

Sales & Ordering FAQs

Part Models 2

1ku List Price Starting From $2.85

Documentation

Technical Documents 2

LT8440: Power Conditioner for APL Field Devices Data Sheet (Rev.0) 07/26/2024

EVAL-LT8440-AZ User Guide: Power Conditioner for APL Field Devices (Rev.0) 07/26/2024

Design Resources 2

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
LT8440RS8E#PBF	8-Lead SOIC (Narrow 0.15 Inch w/ EP)	HTML Material Declaration HTML Reliablity Data	Ultra Librarian SamacSys
LT8440RS8E#TRPBF	8-Lead SOIC (Narrow 0.15 Inch w/ EP)	HTML Material Declaration HTML Reliablity Data	Ultra Librarian SamacSys

LT8440RS8E#PBF
Pin/Package Drawing
8-Lead SOIC (Narrow 0.15 Inch w/ EP)
Documentation

HTML Material Declaration

HTML Reliablity Data

CAD Symbols, Footprints, and 3D Models
Ultra Librarian
SamacSys

LT8440RS8E#TRPBF
Pin/Package Drawing
8-Lead SOIC (Narrow 0.15 Inch w/ EP)
Documentation

HTML Material Declaration

HTML Reliablity Data

CAD Symbols, Footprints, and 3D Models
Ultra Librarian
SamacSys

Software & Part Ecosystem

Evaluation Kit

EVAL-LT8440-AZ

Power Conditioner for APL Field Devices

Power Conditioner for APL Field Devices

Download

EVAL-LT8440-AZ

Power Conditioner for APL Field Devices

Buy Now View Details

Product Detail

The EVAL-LT8440-AZ evaluation circuit features the LT8440 used in a load power port of an intrinsically safe field device. It can regulate and limit the power drawn by the port according to the Ethernet Advanced Physical Layer (Ethernet-APL) standard. The EVAL-LT8440-AZ is designed with three LT8440s in series to meet the triple redundancy requirement of intrinsic safety Ex ia for class A field devices, but it can be configured to work with a lower LT8440 count. See the Redundancy of LT8440 section for more details.

The evaluation circuit is also equipped with filters and protection components to meet the Ethernet-APL and intrinsic safety standards, including IEC60079-11 and IEC60079-47 standards. Communication signal integrity is well preserved on this evaluation circuit, allowing seamless link up between 10BASE-T1L devices.

The EVAL-LT8440-AZ board is designed to operate from 9V to 17.5V input voltage. Across the input voltage range, the LT8440 draws current in parallel with the load up to the 500mW minimum guaranteed for Class A load power ports in compliance with Advanced Physical Layer (APL) standards. In case of load circuit failures, the evaluation board also limits input power below 650mW. The LT8440 shunts current even at no load to ensure at least 20mA input current during normal operation, which is required by APL specification for signal integrity.

Design files for this circuit board are available at Product Evaluation Boards and Kits | Design Center | Analog Devices.

Resources

PDF

EVAL-LT8440-AZ User Guide: Power Conditioner for APL Field Devices (Rev.0)