AAT4290/91
I/O Expander Load Switches with Serial Control
Timing Diagram
OUTn
TR
TD(ON)
TO
TD(OFF)
THI
TLO
TLAT
EN/SET
to sequence the outputs in order from OUT5 to
OUT1, five clocks bursts are input on the EN/SET
pin. From Table 1, the first burst of 16 clocks turns
on OUT5. A following burst of 8 clocks (as the
counter resets) will add OUT4, followed by 4 clocks
to add OUT3, 2 clocks to add OUT2, and 1 clock to
add OUT1. Likewise, the outputs can be turned off
in any order by adding more clock bursts.
Output Sequencing
If output sequencing is not necessary, then all of the
outputs will be switched on simultaneously on the
first rising edge of the EN/SET pin. However, if out-
put sequencing is desired, then a series of pulses
on the EN/SET pin will accomplish this. Each time
a new group of pulses is asserted on EN/SET, the
AAT4290/91 internal control is reset. For example,
10
4290.2006.03.1.2
AAT [ ADVANCED ANALOG TECHNOLOGY, INC. ]
