Sequencers, Trackers, and Margining Controllers

Linear Technology’s sequencers, trackers and margining controllers provide additional functionality to one or multiple power supplies. Our sequencing controllers allow power supplies to be turned on or off in any order by adding time delays to each supply. In a tracking-based system, a master voltage rail is chosen, typically the highest voltage rail, and all of the lower voltage rails are slaved to the on-ramp or off-ramp of the master voltage rail. When testing power supplies in an automated PCB test environment, a margining controller allows power supply output voltages to be precisely adjusted up and down by sourcing or sinking current into the feedback node or voltage adjust pin of the power supply; this allows a system to test the correct operation of electrical components at the upper and/or lower power supply voltage limits specified for a given design. These products enable intelligent system monitor and control for industrial, telecom, automotive and other high reliability systems.

Although there are power supplies which incorporate sequencing, tracking or margining functionality, our dedicated controllers provide benefits not readily available on most DC/DC controllers. The LTC2928 cascadable sequencer and supervisor provides high integration and the ability to configure up to four power supplies without software, while the automatic remote sense switching used in the LTC2921 3-supply and LTC2922 5-supply trackers allows DC/DC converters to compensate for series voltage drops in the wiring. The LTC2920 single and LTC2921 dual margining controllers work with any power supplies that have a feedback pin (or are modeled as such) and provide a 400:1 current programming range with greater than 0.4% accuracy. The programmable LTC2937, with EEPROM, sequences (time and event based) 6 supplies and supervises them with ±0.75% accurate undervoltage and overvoltage thresholds.

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