Connector and Test Point Descriptions
6
SNVU588 – November 2017
Copyright © 2017, Texas Instruments Incorporated
TPS40345EVM-353 Evaluation Module
4.3.1
Input Voltage Monitoring (TP1 and TP2)
The TPS40345EVM-353 provides two test points for measuring the input voltage applied to the module.
This allows the user to measure the actual input module voltage without losses from input cables and
connectors. All input voltage measurements should be made between TP1 and TP2. To use TP1 and
TP2, connect a voltmeter positive input to TP1 and input terminal to TP2.
4.3.2
Output Voltage Monitoring (TP3 and TP4)
The TPS40345EVM-353 provides two test points for measuring the output voltage generated by the
module. This allows the user to measure the actual module output voltage without losses from input
cables and connectors. All input voltage measurements should be made between TP3 and TP4. To use
TP3 and TP4, connect a voltmeter positive input to TP3 and negative input to TP4.
4.3.3
Loop Response Testing (TP5, TP6, TP7, TP8, and R3)
The TPS40345EVM-353 provides four test points (2 signal and 2 ground) for measuring the control loop
frequency response. This allows the user to measure the actual module loop response without modifying
the evaluation board. A transformer isolated signal up to 30 mV can be injected between TP5 and TP7.
The injected signal amplitude can be measured by the ac coupled amplitude at CHA (TP7) and the
resulting output voltage deviation can be measured at CHB (TP5). See
for additional detail.
4.3.4
Error Amplifier Voltage Monitoring (TP9, TP10, and TP11)
The TPS40345EVM-353 provides three test points for measuring the error amplifier input and output
voltages. This allows the user to directly measure the feedback and control voltages of the TPS40304
controller. The control voltage (TP10) can also be used to measure the control to output or power-stage
frequency response or output to control or error amplifier frequency response. See
for
additional details.
4.3.5
Switching Waveform Monitoring (TP12, TP13, TP14, and TP15)
The TPS40345EVM-353 provides three test points and a local power ground for measuring the switching
waveforms of the module power stage. This allows the user to monitor actual switching waveforms during
operation. TP13 is a 0.040-inch square pad of exposed PCB copper to minimize EMI radiation from the
high transient voltages on the switch node. Switching waveform measurements should be made using
power ground (TP15) as the ground reference for more accurate measurements.
4.3.6
Power-Good Voltage Monitoring (TP16 and TP18)
The TPS40345EVM-353 provides a test point and local ground for measuring the power good output
voltage. A 100-k
Ω
resistor pullup to BP (R9) is included to allow the power-good signal to be monitored
without requiring an external pull-up. For true open-drain operation with no pullup, remove R9. With R9
removed, TP16 can be connected to TP17 of another TPS40345EVM-353 to provide sequential start-up of
the two TPS40345EVM-353 converters.
4.3.7
Enable and Soft-Start Voltage Monitoring (TP17 and TP18)
The TPS40345EVM-353 provides a test point and local ground for measuring the enable and soft-start
voltage. TP17 and TP18 or JP2 can be used to provide an external enable signal. Due to the nature of the
soft-start function, the external signal must be open-collector or open-drain without pullup.