Datasheet
1.3 Modifications
1.3.1 Output Voltage Set Point
( )
6
0.8
10
0.8
-
= W ´
OUT
V V
R k
V
(1)
2 Test Setup and Results
2.1 Input / Output Connections
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Test Setup and Results
These evaluation modules are designed to provide access to the features of the TPS54140. Some
modifications can be made to this module.
To change the output voltage of the EVM, it is necessary to change the value of resistor R
6
. Changing the
value of R
6
can change the output voltage above 0.8 V. The value of R
6
for a specific output voltage can
be calculated using Equation 1 .
Table 3 lists the R
6
values for some common output voltages. Note that V
IN
must be in a range so that the
minimum on-time is greater than 130 ns, and the maximum duty cycle is less than 91%. The values given
in Table 3 are standard values, not the exact value calculated using Equation 1 .
Table 3. Output Voltages Available
Output Voltage (V) R
6
Value (k Ω )
1.8 12.4
2.5 21.5
3.3 31.6
5 52.3
Be aware that changing the output voltage can affect the loop response. It may be necessary to modify
the compensation components. See the datasheet for details.
This section describes how to properly connect, set up, and use the TPS54140EVM-429 evaluation
module. The section also includes test results typical for the evaluation module and covers efficiency,
output voltage regulation, load transients, loop response, output ripple, input ripple, and start-up.
The TPS54140EVM-429 is provided with input/output connectors and test points as shown in Table 4 . A
power supply capable of supplying 1A must be connected to J1 through a pair of 20 AWG wires. The load
must be connected to J4 through a pair of 20 AWG wires. The maximum load current capability must be
1.5 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. TP9 is used to monitor
the output voltage with TP10 as the ground reference.
SLVU285 – March 2009 TPS54140EVM-429 1.5-A, SWIFT™ Regulator Evaluation Module 3
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