TPS54383, TPS54386
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SLUS774B–AUGUST 2007–REVISED OCTOBER 2007
TERMINAL FUNCTIONS (continued)
TERMINAL
I/O
DESCRIPTION
NAME
NO.
This pin configures the output startup mode. If the SEQ pin is connected to BP, then when Output 2 is
enabled, Output 1 is allowed to start after Output 2 has reached regulation; that is, sequential startup
where Output 1 is slave to Output 2. If EN2 is allowed to go high after the outputs have been operating,
then both outputs will be disabled immediately, and the output voltages will decay according to the load
that is present. For this sequence configuration, tie EN1 to ground.
If the SEQ pin is connected to GND, then when Output 1 is enabled, Output 2 is allowed to start after
Output 1 has reached regulation; that is, sequential startup where Output 2 is slave to Output 1. If EN1
is allowed to go high after the outputs have been operating, then both outputs will be disabled
immediately, and the output voltages will decay according to the load that is present. For this sequence
configuration, tie EN2 to ground.
SEQ
10
I
If left floating, Output 1 and Output 2 start ratio-metrically when both outputs are enabled at the same
time. They will soft start at a rate determined by their final output voltage and enter regulation at the
same time. If the EN1 and EN2 pins are allowed to operate independently, then the two outputs also
operate independently
NOTE: An internal two resistor (150-kΩ each) divider connects BP to SEQ and to GND. See the
Sequence States table.
Source (switching) output for Output 1 PWM. A snubber is recommended to reduce ringing on this
node. See SW Node Ringing for further information.
SW1
3
O
Source (switching) output for Output 2 PWM. A snubber is recommended to reduce ringing on this
node. See SW Node Ringing for further information.
SW2
12
-
O
-
Thermal Pad
This pad must be tied externally to a ground plane and the GND pin.
10
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