Super Sequencer® with Open-Loop Margining DACs

The ADM1067 Super Sequencer® is a configurable supervisory/ sequencing device that offers a single-chip solution for supply monitoring and sequencing in multiple supply systems. In addition to these functions, the ADM1067 integrates six 8-bit voltage output DACs. These circuits can be used to implement an open-loop margining system that enables supply adjustment by altering either the feedback node or reference of a dc-to-dc converter using the DAC outputs.

Supply margining can be performed with a minimum of external components. The margining capability can be used for in-circuit testing of a board during production (for example, to verify board functionality at −5% of nominal supplies), or it can be used dynamically to accurately control the output voltage of a dc-to-dc converter.

The device also provides up to 10 programmable inputs for monitoring undervoltage faults, overvoltage faults, or out-of-window faults on up to 10 supplies. In addition, 10 programmable outputs can be used as logic enables.

Six of these programmable outputs can also provide up to a 12 V output for driving the gate of an N-FET that can be placed in the path of a supply.

The logical core of the device is a sequencing engine. This state-machine-based construction provides up to 63 different states. This design enables very flexible sequencing of the outputs, based on the condition of the inputs.

The device is controlled via configuration data that can be programmed into an EEPROM. The entire configuration can be programmed using an intuitive GUI-based software package provided by Analog Devices, Inc.

Applications

* Office systems

* Servers/routers

* Multivoltage system line cards

* DSP/FPGA supply sequencing

* In-circuit testing of margined supplies

* Complete supervisory and sequencing solution for up to 10 supplies * 10 supply fault detectors enable supervision of supplies to <0.5% accuracy at all voltages at 25°C <1.0 % accuracy across all voltages and temperatures * 5 selectable input attenuators allow supervision Supplies up to 14.4 V on VH Supplies up to 6 V on VPn (VP1 to VP4) * 5 dual-function inputs, VXn (VX1 to VX5) High impedance input to supply fault detector with thresholds between 0.573 V and 1.375 V General-purpose logic input * Open collector with external pull-up * Push/pull output, driven to VDDCAP or VPn * Open collector with weak pull-up to VDDCAP or VPn * Internally charge-pumped high drive for use with external N-FET (PDO1 to PDO6 only) * Open-loop margining solution for 6 voltage rails * 6 voltage output 8-bit DACs (0.300 V to 1.551 V) allow voltage adjustment via dc-to-dc converter trim/feedback node