Texas Instruments TPS54325, User Manual

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1 Introduction
This user’s guide contains background information for the TPS54325 as well as support documentation for the
TPS54325EVM evaluation module. Also included are the performance specifications, schematic and the bill of
materials for the TPS54325EVM.
1.1 Background
The TPS54325 is a single, adaptive on-time D-CAP2 ™ mode synchronous buck converter. System designers
may use the TPS54325 to complete various end equipment dc/dc converters with a low cost, low component
count, low standly current solution. The main control loop for the TPS54325 uses the D-CAP2
™ mode that
optimized for low ESR output capacitors such as POSCAP, SP-CAP, High Polymer Chemistry or ceramic types.
This control loop implementation provides fast transient response with no external compensation components.
The TPS54325 dc/dc synchronous converter is designed to provide up to a 3-A output from an input control
voltage source (VCC) of 4.5 V to 18 V, input power voltage source (VIN) of 2.0 V to 18 V and output voltage from
0.76 V to 5.5 V. Rated input voltage and output current range for the evaluation module are given in
Table 1-1 .
Table 1-1. EVM Input Voltage and Output Current Summary
EVM INPUT VOLTAGE RANGE OUTPUT CURRENT RANGE
TPS54325EVM V
IN
= 5 V to 17 V 0 A to 3 A
1.2 Performance Specification Summary
A summary of the EVM performance specifications is provided in Table 1-2 . Specifications are given for an input
voltage of V
IN
= 12 V and an output voltage of 1.05 V, unless otherwise noted. The VIN and VCC input voltage
pins are cnnected on the EVM using a 0-Ω resistor (R9). The ambient temperature is 25°C for all measurement,
unless otherwise noted.
Table 1-2. TPS54325EVM Performance Specifications Summary
SPECIFICATION TEST CONDITIONS MIN TYP MAX UNIT
Input voltage range (V
IN
) 5 12 17 V
Output voltage 1.05 V
Operating frequency V
IN
= 12 V, I
out1
= 1 A 700 kHz
Output current range 0 3 A
Over current limit V
IN
= 12 V 4.1 A
Output ripple voltage V
IN
= 12 V, I
out1
= 3 A 9 mVp-p
Efficiency V
IN
= 12 V, V
OUT
= 3.3 V, I
OUT
= 1.2 A 91 %
1.3 Modifications
These evaluation modules are designed to provide access to the feature set of the TPS54325. Some
modification can be made to these modules.
1.3.1 Output Voltage Set Point
The output voltage of the EVM is set using the voltage divider of R1 + R4 and R2. To change the output voltage
of the EVMs, it is necessary to change the value of resistors R1 and R4 while leaving R2 fixed. Changing the
value of R1 and R4 can change the output voltage above 0.765 V.The value of R1 and R4 for a specific output
voltage basically can be calculated using
Equation 1 .
1
0.765 (1 )
2
R R
V
O
R
= · +
+
4
(1)
Table 1-3 lists the each R1 and R4 value for some common output voltages. C9 is used for faster load transient
response and is not normally used. Note that the values given in Table 1-3 are standard values, and not the
exact value calculated using Table 1-3 .
www.ti.com Introduction
SLVU300A – JUNE 2009 – REVISED OCTOBER 2021
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