Datasheet

UCD90124A

SLVSAN8 –JANUARY 2012

www.ti.com

fault-shutdown slaves sequence-off, the UCD90124A waits for a programmable delay time between 0 and 1275

ms in increments of 5 ms and then sequences-on the faulted rail and fault-shutdown slaves according to the

start-up sequence configuration. This is repeated until the faulted rail and fault-shutdown slaves successfully

achieve regulation or for a user-selected 1, 2, 3, or 4 times. If the resequence operation is successful, the

resequence counter is reset if all of the rails that were resequenced maintain normal operation for one second.

Once shut-down-all-rails and sequence-on begin, any faults on the fault-shutdown slave rails are ignored. If there

are two or more simultaneous faults with different fault-shutdown slaves, the more conservative action is taken.

For example, if a set of rails is already on its second resequence and the device is configured to resequence

three times, and another set of rails enters the resequence state, that second set of rails is only resequenced

once. Another example – if one set of rails is waiting for all of its rails to shut down so that it can resequence,

and another set of rails enters the resequence state, the device now waits for all rails from both sets to shut

down before resequencing.

GPIOs

The UCD90124A has 22 GPIO pins that can function as either inputs or outputs. Each GPIO has configurable

output mode options including open-drain or push-pull outputs that can be actively driven to 3.3 V or ground.

There are an additional four pins that can be used as either inputs or PWM outputs but not as GPOs. Table 4

lists possible uses for the GPIO pins and the maximum number of each type for each use. GPIO pins can be

dependents in sequencing and alarm processing. They can also be used for system-level functions such as

external interrupts, power-goods, resets, or for the cascading of multiple devices. GPOs can be sequenced up or

down by configuring a rail without a MON pin but with a GPIO set as an enable.

Product Folder Link(s) :UCD90124A