Datasheet
Table Of Contents
- FEATURES
- APPLICATIONS
- CONTENTS
- DESCRIPTION
- DEVICE RATINGS
- ABSOLUTE MAXIMUM RATINGS
- RECOMMENDED OPERATING CONDITIONS
- ELECTROSTATIC DISCHARGE (ESD) PROTECTION
- PACKAGE DISSIPATION RATINGS
- ELECTRICAL CHARACTERISTICS
- TYPICAL CHARACTERISTICS
- DEVICE INFORMATION
- BLOCK DIAGRAM
- APPLICATION INFORMATION
- FUNCTIONAL DESCRIPTION
- Voltage Reference
- Oscillator
- Input Undervoltage Lockout (UVLO) and Startup
- Enable and Timed Turn On of the Outputs
- Output Voltage Sequencing
- Soft Start
- Output Voltage Regulation
- Feedback Loop and Inductor-Capacitor (L-C) Filter Selection
- Inductor-Capacitor (L-C) Selection
- Maximum Output Capacitance
- Minimum Output Capacitance
- Modifying The Feedback Loop
- Example: TPS54386 Buck Converter Operating at 12-V Input, 3.3-V Output and 400-mA(P-P) Ripple Current
- Bootstrap for the N-Channel MOSFET
- Light Load Operation
- SW Node Ringing
- Output Overload Protection
- Operating Near Maximum Duty Cycle
- Dual Supply Operation
- Cascading Supply Operation
- Multiphase Operation
- Bypass and FIltering
- Over-Temperature Protection and Junction Temperature Rise
- Power Derating
- PowerPAD Package
- PCB Layout Guidelines
- FUNCTIONAL DESCRIPTION
- DESIGN EXAMPLES
- ADDITIONAL REFERENCES
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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 are disabled immediately, and the output voltages 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 are disabled immediately,
SEQ 10 I
and the output voltages 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 3 O
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 12 O
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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