Texas Instruments TPS54673EVM-225, Руководство пользователя, Страница: 12 / 42

Background
1-2
1.1 Background
The TPS54x73EVM-225 evaluation module uses the TPS54673 or TPS54873
synchronous buck regulators with disabled sink during start-up (DSDS) to
provide an output voltage of from 0.9 V to 2.5 V from a nominal 3.3 V input or
0.9 V to 3.3 V for a nominal 5-V input. Rated input voltage and output current
range is given in Table 1–1. These EVMs are designed to demonstrate the
small PCB areas that may be achieved when designing with the TPS54x73
family of regulators. The swicthing frequency is set at a nominal 700 kHz,
allowing the use of a small footprint 0.65
µ
H output inductor. The MOSFETs
of the TPS54x73 are incorporated inside the TPS54x73 package. This
eliminates the need for external MOSFETs and their associated drivers. The
low drain-to-source on resistance of the MOSFETs gives the TPS54x73 high
efficiency and helps to keep the junction temperature low at high output
currents. The compensation components are provided external to the IC, and
they allow for an adjustable output voltage and a customizable loop reponse.
The disabled sink during start-up (DSDS) feature allows the TPS54x73 family
of regulators to be used in applications where it is necessary to prebias the
output to maintain a specified difference between I/O and core voltages during
start-up.
Table 1–1. Input Voltage and Output Current Summary
EVM Input Voltage Range Output Current Range
TPS54673EVM-225 3.0 V to 6.0 V –6 A to 6 A
TPS54873EVM-225 4.0 V to 6.0 V –8 A to 8 A
1.2 Performance Specification Summary
A summary of the TPS54x73EVM–225 performance specifications is provided
in Table 1–2 and Table 1–3. All specifications are given for an an output
voltage of 3.3 V and an output voltage of 2.5 V for the TPS54673 and an uput
voltage of 5 V and an output voltage of 3.3 V for the TPS54873. The ambient
temperature is 25
°
C, for all measurements, unless otherwise noted. The data
presented in Table 1–2 and Table 1–3 are compiled with no precharge on the
output (J3 open, no voltage source present on J4). Using the precharge
circuitry on this EVM requires careful consideration of line and load conditions
for proper operation and may limit the useful operating range of the TPS54x73
device.