Analog Devices MAX Line Protects Embedded Compute from Power Surges

November 05, 2024

Blog

In the world of Embedded Computing, power management is one of the key pillars to any system’s design. Keeping power use optimized and efficient is important, of course, but also, managing the risks of power surges.

A power surge can damage, disable, or destroy the most robust embedded computers if they aren’t well protected, so making that part of the design is a wise choice.

The MAX17616/MAX17616A from Analog Devices is designed to offer versatile and programmable protection boundaries for systems against input voltage faults and output overcurrent faults. Input-voltage faults (with positive polarity) are protected up to +80V (without Reverse Current Protection)/+75V (with Reverse Current Protection), by an internal nFET featuring low ON-resistance (20mΩ typ), according to the company.

The devices offer programmable undervoltage-lockout (UVLO) thresholds by using external voltage-dividers. The MAX17616 features a programmable overvoltage-lockout (OVLO) while MAX17616A offers a programmable output voltage clamp function through the OVFB pin that features an output voltage limiting regulation during input transient surge events. Input undervoltage and overvoltage protection (MAX17616)/output voltage clamp function (MAX17616A) can be programmed across the entire 3V to 80V operating range.

To achieve input reverse-polarity protection, the devices use an external nFET, and the magnitude is dependent on the operating load-bus voltage (VOUT ) and the voltage-blocking capability of the external nFET. The external nFET is also needed for the optional reverse-current protection. When used with a Reverse Protection external nFET (Q1), the devices prevent reverse current flow from load to source by turning off Q1.

The current limit of the devices is programmed by connecting a resistor from the SETI pin to GND and it can be programmed from 0.7A to 7.0A. When the current through the devices reaches or exceeds the set current limit, the resistance of the internal nFET is modulated to limit the current.

The device can be turned ON or OFF by enabling input EN by a controller supervisory system. This allows the controller supervisory system to Turn ON or OFF the power delivery to connected loads. The devices offer loss-of-ground protection where it safely turns OFF the device operation during a loss-of-ground fault event, i.e., when the safety ground fuse opens in a redundant safety application.

The devices offer a status announcement signal (SMBALERT) to indicate operational and fault signals. The devices also offer a Power Good Signal (PGOOD/TJ) that may be used by a supervisory system to enable/disable the downstream loads. PGOOD/TJ is an open drain pin and requires an external pullup resistor to the appropriate system interface.

They have a programmable output undervoltage sense threshold that governs the restart response after the output voltage drops below the OUTUV Rising threshold, and they have internal thermal shutdown protection against excessive power dissipation.

APPLICATIONS

These programmable surge protection solutions are applicable almost anywhere they embedded computing is connected to power. Analog Devices says that they’re particularly well suited to Input Voltage and Output Overcurrent Protections, anytime there is loss of Ground Protection, or the need for surge protection.

Features:

• Robust Protection Reduces System Downtime
  • Wide Input Supply Range: +3V to +80V (without Reverse Current Protection)
  • Wide Input Supply Range: +3V to +75V (with Reverse Current Protection)
  • ±3% Accurate Programmable Current Limit between 3A to 7A across Full Temperature Range
  • ±4% Accurate Programmable Current Limit between 2A to 3A across Full Temperature Range
  • ±7% Accurate Programmable Current Limit between 0.7A to 2A across Full Temperature Range
  • Input-Voltage Reverse-Polarity Protection (with External nFET)
  • Dual Stage Reverse Current Protection (with External nFET) with Fast 100ns Response Time
  • Low RON Internal nFET (20mΩ typ)
  • Output-Voltage Reverse-Polarity Tolerant
  • Loss of Ground Protection
  • 200% Short Term Overload capability
  • Programmable Overvoltage Surge Protection (MAX17616A)
• PMBus Interface
  • Real Time Operating Conditions Monitoring, Voltage and Current Readout
  • Fault Registry Access and Management
  • Device ON/OFF Control
  • Current Limit Mode Selection
  • Startup Inrush Current Limit Selection
  • Short Term Over Current Limit and Time Selection

• Flexible Design to Maximize Reuse and Minimize Requalification
  • Adjustable UVLO and OVLO/OVFB Thresholds
  • ±2% Accurate Bandwidth Current Monitoring Read-Out, IMON (3A to 7A, up to +85ºC)
  • Programmable Startup Inrush Current Limit
  • Programmable Current Limit Fault Response: Continuous, Autoretry, and Latch-off Modes
  • Logic Level Enable Input (EN)
  • Protected External n-type field effect transistor (nFET) Gate Drive
  • Power Good Output (PGOOD)
  • Programmable Output Under Voltage Sense (OUTUV)
  • Junction Temperature Monitoring (TJ)
  • Thermal Foldback Current Limit
• Reduced Solution Footprint
  • 4.5mm x 5.75mm, 23-Pin FCQFN package
  • Integrated nFET for Common-Use Protection Requirements

 

Protecting an embedded device from the elements is always a challenge, but when the danger can come from the very power source that’s driving the compute, the protections need to be even more robust. That’s why next generation surge and power protection is in demand.