The LTC2937 is designed to supervise and control FPGA/ASIC/microprocessor PoL supplies, which require tight accuracy and complex sequencing to avoid damage to the processor. The sequencer turns supplies on and off in a programmable order, separated either with adjustable time delays or by qualifying events (i.e. crossing voltage thresholds). Once sequenced, a supply is monitored with ±0.75% accurate under-voltage and over-voltage thresholds. The supply sequencing and monitoring meets the sequencing and tolerance requirements of supplies in high-availability computers and servers, network routers and switches, enterprise data storage systems and telecommunications equipment.

The flexible sequencing technique turns a supply on or off in any one of 1,023 possible sequence positions. A sequence position may be occupied by zero, one or multiple supplies. Empty (or reserved) sequence positions allow for addition of power supplies late in a board design. A simple single wire connection synchronizes up to 50 LTC2937s for sequencing expansion to 300 supplies, simplifying board routing. Sequencing is interleaved between multiple sequencers.

An I²C/SMBus digital interface affords register configuration and read back of the sequence positions and delays, supervisor thresholds, fault response and system status. Thresholds are 8bit programmable from 0.2 to 6V in three range settings, including an adjustable range for greater than 6V and negative voltage supplies. Faults trigger logging to internal EEPROM, speeding debug and failure analysis. Register configuration may be accomplished through the LTpowerPlay development environment; there is no need to write software code for autonomous operation. The device directly powers off a 12V intermediate bus, saving the space and cost of an external step-down DC/DC converter. The reset output’s release delay is programmable and the reset can be disabled during board margin testing.  A regulated 3.3V output enables level shifting for monitoring negative supplies.

The device is specified over the 0 to 70°C commercial and -40 to 85°C industrial temperature ranges and is offered in a 28-lead 5.0 x 6.0mm QFN package.