Datasheet

OUT

(V - 0.827 V)

R6 = 10 kΩ ×

0.827 V

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Test Setup and Results

1.3 Modifications

These evaluation modules are designed to provide access to the features of the TPS54319. Some

modifications can be made to this module.

1.3.1 Output Voltage Set Point

The voltage divider of R6 and R7 is used to set the output voltage of the EVM. The 51.1 Ω resistor R8 is

provided as an aid to check the loop response of the circuit. To change the output voltage of the EVM, it is

necessary to change the value of resistor R6. Changing the value of R6 can change the output voltage

above 0.8 V. The value of R6 for a specific output voltage can be calculated using Equation 1.

(1)

Table 3 lists the R6 values for some common output voltages. Note that V

must be in a range so that the

minimum on-time is greater than 130 ns, and the maximum duty cycle is less than 94%. Higher duty

cycles are possible, but may result in uneven switching behavior. The values given in Table 3 are

standard values, not the exact value calculated using Equation 1.

Table 3. Common Output Voltages

Output Voltage R6 Value

(V) (kΩ)

1.2 4.53

1.5 8.06

1.8 11.8

2.5 20.0

3.3 30.1

Be aware that changing the output voltage can affect the loop response. It may be necessary to modify

the compensation components. See the data sheet (SLVSA83) for details.

1.3.2 Operating Frequency, Slow-Start and UVLO

The operating frequency, slow-start time and UVLO voltage may also be adjusted. R5 sets the operating

frequency, C7 sets the slow-start time and the resistor divider of R1 and R2 sets the UVLO start and stop

voltages. See the TPS54319 (SLVSA83) data sheet for details on adjusting these parameters.

2 Test Setup and Results

This section describes how to properly connect, set up, and use the TPS54319EVM-626 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.

2.1 Input/Output Connections

The TPS54319EVM-626 is provided with input/output connectors and test points as shown in Table 4. A

power supply capable of supplying 1.5 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 must

be 2.5 A. Wire lengths must be minimized to reduce losses in the wires. Test-point TP1 provides a place

to monitor the V

input voltages with TP2 providing a convenient ground reference. TP9 is used to monitor

the output voltage with TP10 as the ground reference.

SLVU377–May 2010 TPS54319EVM-626 3-A, SWIFT™ Regulator Evaluation Module