.
C communication. This terminal
鈩?/div>
resistor. Refer to
I
2
C Bus Operation on page 26
for more
information on this terminal.
ENABLE 1 AND 2 TERMINALS (EN1 AND EN2)
These two terminals permit positive logic control of the
Enable function and selection of the Power Sequencing
mode concurrently.
Table 5
depicts the EN1 and EN2
function and Power Sequencing mode selection.
Both EN1 and EN2 terminals have internal pulldown
resistors and both can withstand a short circuit to the supply
voltage, 6.0 V.
Table 5.
EN1
0
0
1
1
RESET OUTPUT TERMINAL (
RST
)
The Reset Control circuit monitors both the switching
regulator and the LDO feedback voltages. It is an open drain
output and has to be pulled up to some supply voltage (e.g.,
the output of the LDO) by an external resistor.
The Reset Control circuit supervises both output
voltages鈥攖he linear regulator output V
LDO
and the switching
regulator output V
OUT
. When either of these two regulators
is out of regulation (high or low), the
RST
terminal is pulled
low. There is a 20
碌
s delay filter preventing erroneous resets.
During power-up sequencing,
RST
is held low until the Reset
Timer times out.
Operating Mode Selection
EN2
0
1
0
1
Operating Mode
Regulators Disabled
Standard Power Sequencing
Inverted Power Sequencing
No Power Sequencing,
Regulators Enabled
CLOCK SELECTION TERMINAL (CLKSEL)
This terminal sets the CLKSYN terminal as either an
oscillator output or a synchronization input terminal. The
CLKSEL terminal is also used for the I
2
C address selection.
CLOCK SYNCHRONIZATION TERMINAL (CLKSYN)
Oscillator output/synchronization input terminal.
34701
16
Analog Integrated Circuit Device Data
Freescale Semiconductor