TPS2371

SLUS566A − JULY 2003 − REVISED NOVEMBER 2003

5

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DETAILED PIN DESCRIPTIONS (continued)

EN_DC (Pin 6)

Enable pin for the load. This pin is intended to be used with a dc-to-dc coverter with a soft start capacitor. When

power is not available to the dc-to-dc converter, this pin sinks 80-

µA and hold off the softstart cap on the dc-to-dc

converter. Once the voltage across the load is within 1.5 V of its final value, the EN_DC pin stops drawing current

and become high impedance, allowing the dc-to-dc to soft start normally.

DELAY (Pin 7)

This pin controls the amount of time that the device ignores an undervoltage condition on VDD. That time is set

by the following equation:

T

100 ms

mF

C

DELAY

VDD (Pin 8)

Positive supply to the device.

Table 1. PoE Classification Resistance Values

CLASS

RESISTANCE

(RCLASS) VALUE (Ω)

POWERED DEVICES

(PDs) Power (W)

CLASSIFICATION

CURRENT (mA)

0

4420

0.44 − 12.95

2.5

1

953

0.44 − 3.84

10.8

2

549

3.84 − 6.49

18.6

3

357

6.49 − 12.95

28.4

4

255

reserved for future use

39.6

(2)