SMS45
Preliminary Information
PIN DESCRIPTIONS (CONTINUED)
A1,A2 (6, 7)
A1 and A2 are the address inputs. When addressing the
SMS45 memory or configuration registers the address
inputs distinguish which one of four possible devices
sharing the common bus is being addressed.
SDA (9)
SDA is the serial data input/output pin. It should be tied to
VDD_CAP through a pull-up resistor.
SCL (10)
SCL is the serial clock input. It should be tied to VDD_CAP
through a pull-up resistor.
PUP#1, PUP#2, PUP#3 (4, 5, 13)
These are the power-up permitted (PUP) active low open
drain outputs. The PUP pins are used when the SMS45 is
programmed to provide the cascade sequencing of LDOs
or DC/DC converters (see
Figures 1 and 5 for illustra-
tions of cascading).
Each delay is independently enabled
and programmable for its duration (configuration
register
7).
If all PUP# outputs are enabled the order of events
would be as follows: V
0
above threshold then delay to
PUP#1 turning on; V
1
above threshold then delay to PUP#2
turning on; V
2
above threshold then delay to PUP#3 turning
on. The delays are programmable.
SUMMIT MICROELECTRONICS, Inc.
2079 1.2 05/24/04
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