TPS54386PWPR datasheet(10/52 Pages) TI

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TPS54383,, TPS54386

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

SEQ

immediately, and the output voltages will decay according to the load that is present. For this sequence

configuration, tie EN2 to ground.

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-k

Ω 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

SW1

node. See SW Node Ringing for further information.

Source (switching) output for Output 2 PWM. A snubber is recommended to reduce ringing on this

SW2

node. See SW Node Ringing for further information.

Thermal Pad

This pad must be tied externally to a ground plane and the GND pin.

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