(5 V/div)

(2 V/div)

(2 A/div)

t − Time − 4 ms/div

PTR08060W

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SLTS289G – AUGUST 2007 – REVISED MARCH 2013

Power-Up Characteristics

When configured per the standard application, the PTR08060W power module produces a regulated output

voltage following the application of a valid input source voltage. During power up, internal soft-start circuitry slows

the rate that the output voltage rises, thereby limiting the amount of in-rush current that can be drawn from the

input source. The soft-start circuitry introduces a short time delay (typically 10 ms) into the power-up

characteristic. This is from the point that a valid input source is recognized. Figure 12 shows the power-up

waveforms for a PTR08060W, operating from a 12-V input and with the output voltage adjusted to 3.3 V. The

waveforms were measured with a 4-A constant current load.

Figure 12. Power-Up Waveforms

Overcurrent Protection

For protection against load faults, the PTR08060W incorporates output overcurrent protection. Applying a load

that exceeds the regulator's overcurrent threshold causes the regulated output to shut down. Following

shutdown, the module periodically attempts to recover by initiating a soft-start power-up. This is described as a

hiccup mode of operation, whereby the module continues in a cycle of successive shutdown and power up until

the load fault is removed. During this period, the average current flowing into the fault is significantly reduced.

Once the fault is removed, the module automatically recovers and returns to normal operation.

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Product Folder Links: PTR08060W