Texas Instruments TPS54225, User Manual

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R1
VO = (0.763 + 0.0017 VO) 1+
R2
æ ö
´ ´ ç
÷
è ø
(2)
Table 1-3 lists the R1 values for some common output voltages. For higher output voltages, a feedforward
capacitor may be required. Pads for this component (C2) are provided on the printed circuit board. C2 is used
for faster load transient response and is normally not used. Note that the values given in
Table 1-3 are standard
values, and not the exact value calculated using Table 1-3 .
Table 1-3. Output Voltages
OUTPUT VOLTAGE (V) R1 (kΩ) R2 (kΩ) C2 (pF) L1 (µH)
1.0 6.81 22.1 2.2
1.05 8.25 22.1 2.2
1.2 12.7 22.1 2.2
1.8 30.1 22.1 3.3
2.5 49.9 22.1 3.3
3.3 73.2 22.1 680 3.3
5.0 121 22.1 220 4.7
2 Test Setup and Results
This section describes how to properly connect, set up, and use the TPS54225EVM-538. The section also
includes test results typical for the evaluation modules and the following:
• Efficiency
• Output load regulation
• Output line regulation
• Load transient response
• Output voltage ripple
• Input voltage ripple
• Start up
• Switching frequency
2.1 Input / Output Connections
The TPS54225EVM-538 is provided with input/output connectors and test points as shown in Table 2-1 . A power
supply capable of supplying 2 A must be connected to J1 through a pair of 20 AWG wires. The load must be
connected to J2 through a pair of 20 AWG wires. The maximum load current capability is 2 A. Wire lengths must
be minimized to reduce losses in the wires. Test point TP1 provides a place to monitor the V
IN
input voltages
with TP2 providing a convenient ground reference. TP8 is used to monitor the output voltage with TP9 as the
ground reference.
www.ti.com Test Setup and Results
SLVU337A – NOVEMBER 2009 – REVISED OCTOBER 2021
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TPS54225 Step-Down Converter Evaluation Module User's Guide 3
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