SMM764
Preliminary Information
Terms and Definitions
Fault-Triggered
This term refers to either a power-off or force-shutdown operation. When a UV, OV, or
sequence termination condition trigger a power-off or force-shutdown a fault triggered power-
off or force-shutdown is said to occur. This sets the restart delay at 2.4s, and can limit the
number of allowable retries. This term has no correlation to the FAULT pin.
This term refers to either a power-off or force-shutdown operation. When either the FS# or
PWR_ON pin is asserted or an I2C command is issued a Command-Triggered power-off or
force-shutdown is said to occur. This sets the restart delay at 12.5ms, and will not limit the
number of allowable retries.
Command-Triggered
ADOC™
Power-off
ADOC (Active DC Output Control) is a proprietary secondary closed loop compensation
control, used to maintain output voltages to ±0.2%.
Power-off sequencing refers to cascaded power-off sequencing unless explicitly noted.
Cascaded power-off sequencing refers to a feedback based supply termination in which each
channel in the previous sequence position is monitored, and the monitored voltage must fall
below a programmable OFF threshold before the next sequence position is allowed to turn
off. Channels in the same sequence position are not capable of Cascaded power-off
sequencing.
Power-on
Power-off sequencing refers to cascaded power-off sequencing unless explicitly noted.
Cascaded power-off sequencing refers to a feedback based supply termination in which each
channel in the previous sequence position is monitored, and the monitored voltage must fall
below a programmable OFF threshold before the next sequence position is allowed to turn
off. Channels in the same sequence position are not capable of Cascaded power-off
sequencing.
Force-shutdown
Sequence-Link™
When all supplies are immediately disabled without regard to sequence position, or any other
quantity.
When more than one SMM764 or SMM766 derivatives are connected creating a seamless
multi-channel network.
UV
Programmed Under Voltage threshold for monitored channels and supplies
Programmed Over Voltage threshold for monitored channels and supplies
Undervoltage Lockout. Prevents voltage at VDD or 12VIN pin from powering the SMM764
until proper operating voltages have been reached.
OV
UVLO
Margin
ADC
The ability to change the nominal output voltage by use of trim pin.
Analog to Digital Converter. Converts analog voltage to digital voltage. SMM764 represents
all measured voltages by 10-bit digital reading.
Retries
The number of times the SMM764 will restart after a Fault-Triggered power-off or force-
shutdown.
Restart
When the SMM764 begins power on sequencing, includes initial power-on sequence.
Delay from restart timer expiration to PUPY pin active
Power-on delay
Power-off delay
Sequence
Programmable delay from VMX off to PUPY inactive
When a supply fails to reach its programmed UV, or OFF, threshold before expiration of
internal timer.
Termination
Monitoring
When any quantity including temperature, and voltage is converted to a digital value by the
ADC and compared against a user programmable setting.
GUI
Graphical user interface. Program that reads from and writes to non-volatile registers on the
SMM764 and displays results in accordance to register function.
Summit Microelectronics, Inc
2098 1.1 6/29/2005
31
SUMMIT [ SUMMIT MICROELECTRONICS, INC. ]
