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Board Setup
3
SLVUAU3 – January 2017
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TPD2S701-Q1 Evaluation Module
If the switch is placed in position 1, the overvoltage set point is determined instead by external resistors
and an internal voltage reference. In this mode, the device can operate with no external voltage applied to
the 'Vref' pin. The EVM is designed with external resistors to always have a 3.6 V overvoltage set point in
mode 1.
Each device also contains a yellow test point that allows the user to measure the corresponding devices
FLT output. Measure the voltage on this pin to record when the device goes into an undervoltage,
overvoltage, or thermal shutdown state to ensure that the device operates as expected.
2.2
Passthrough Evaluation
Devices U1 and U2 are in a configured to allow for USB 2.0 pass-through testing. The two devices are in
a DSK and DGS package respectively, but otherwise are functionality identical. Each has a male and
female USB port that can be plugged into any system with a USB 2.0 port to ensure that the device can
protect existing systems. Plug J9 or J13 into a USB port and then plug a peripheral into J10 or J14 to
ensure that during typical operation the TPD2S701-Q1 has no effect on standard USB operations. While
plugged in, use a probe to apply a voltage above the overvoltage setpoint to one of the data lines and
observe that the TPD2S701-Q1 isolates the system, preventing any data pass-through. After the voltage is
removed, the TPD2S701-Q1 must remove the isolation and quickly re-allow data communications. See
Figure 2
.
By taking advantage of this pass-through evaluation, the user can quickly determine whether the
TPD2S701-Q1 is optimal for their existing system without requiring any board changes or non-optimal test
setups. There is an additional USB 2.0 pass-through setup at the bottom of the board that is designed for
calibration. The board and trace add some parasitics and bandwidth loss that do not reflect how the
TPD2S701-Q1 operates when designed into a system. This additional pass-through allows for calibration
to account for those and get a more accurate picture of the TPD2S701-Q1.
Figure 2. Passthrough Evaluation Configuration