Texas Instruments TPS53125EVM-599 - Manual (Page 5)

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4.2.4 Soft-Start Voltage Monitoring – TP1, TP2, and TP3
TPS53125EVM-599 provides two test points for measuring the soft-start ramp voltages. TP1 monitors the
soft-start ramp of Channel 1. TP2 monitors the soft-start ramp of Channel 2. To use TP1 or TP2, connect
an oscilloscope probe between TP1 or TP2 and TP3.
4.2.5 Switching Node Monitoring – TP3, TP5, and TP11
TPS53125EVM-599 provides two test points for measuring the switching node waveform voltages. TP5
monitors the switching node of Channel 1. TP2 monitors the switching node of Channel 2. To use TP5 or
TP11, connect an oscilloscope probe between TP5 or TP11 and TP3
4.2.6 5-V Regulator Output Monitoring – TP3 and TP10
TPS53125EVM-599 provides a test point for measuring the output of the internal 5-V regulator. TP10
monitors the output voltage of the internal 5-V regulator. To use TP10, connect a voltmeter positive
terminal to TP10 and negative terminal to TP3.
5 Test Setup
5.1 Equipment
The following equipment is recommended for testing the TPS53125EVM-599 evaluation board.
5.1.1 Voltage Source
The input voltage source, V
VIN
, must be a 0-V to 15-V, variable dc source capable of supplying 3 Adc
minimum.
5.1.2 Meters
A1: 0-Adc to 4-Adc ammeter
V1: VIN, 0-V to 22-V voltmeter
V2: VOUT1, 0-V to 2-V voltmeter
V3: VOUT2, 0-V to 2-V voltmeter
5.1.3 Loads
LOAD1: One output load is an electronic load set for constant current mode capable of 0 Adc to 4 Adc at
1.05 Vdc.
LOAD2: The other output load is an electronic load set for constant current mode capable of 0 Adc to 4
Adc at 1.8 Vdc.
5.1.4 Oscilloscope and Probe
The oscilloscope, analog or digital, must be set for ac-coupled measurement with a 20-MHz bandwidth
limiting. Use 20 mV/division vertical resolution, 1.0 µs/division horizontal resolution for the Output Ripple
Voltage Test. Set cursors at +20 mV and –20 mV.
The oscilloscope probe must be a Tektronix P6138 or equivalent oscilloscope probe with exposed
conductive ground barrels.
5.1.5 Recommended Wire Gauge
V
VIN
to J3 – The connection between the source voltage, V
VIN
and J1 of TPS53125EVM-599 can carry as
much as 2 Adc. The minimum recommended wire size is AWG #16 with the total length of wire less than 2
feet (1-foot input, 1-foot return).
5 SLVU392 – July 2010 TPS53125EVM-599
Copyright © 2010, Texas Instruments Incorporated