Si3402-B

6

Rev. 1.0

Table 4. Electrical Characteristics

Parameter

Description

Min

Typ

Max

Unit

VPORT

Detection

2.7

—

11

V

Classification

14

—

22

Undervoltage Lockout

(UVLO) Engaged

(Switching regulator OFF)

——

42

Undervoltage Lockout

(UVLO) Disengaged

(Switching regulator ON)

30

—

36

Transient Surge1

—100

—

Input Offset Current

VPORT < 10 V

—

—

10

µA

Diode Bridge Leakage

VPORT = 57 V

—

—

25

µA

IPORT Classification2

Class 0

0

—

4

mA

Class 1

9

—

12

Class 2

17

—

20

Class 3

26

—

30

Class 4

36

—

44

IPORT Operating Current3

36 V < VPORT < 57 V

—

2

3.1

mA

Current Limit4

Inrush

—

140

—

mA

Operating

470

—

680

mA

Hotswap FET On-Resistance

36 V < VPORT < 57 V

1

—

3



Power Loss (PLOSS) VPORT

Threshold

VPOS - (Greater of CT1 or

CT2), or VPOS - (Greater

of SP1 or SP2)

11.5

2

V

Switcher Frequency

—

350

—

kHz

Maximum Switcher Duty Cycle

—

50

75

%

Switcher Output Transient Voltage

——

100

V

Switching FET On-Resistance

0.3

0.5

1



Regulated Feedback @ Pin FB6

DC Avg.

—

1.35

—

V

Notes:

1. Transient surge defined in IEC60060 as a 1000 V impulse of either polarity applied to CT1–CT2 or SP1–SP2. The

shape of the impulse shall have a 300 ns full rise time and a 50 µs half fall time with 201

 source impedance.

2. The classification currents are guaranteed only when recommended RCLASS resistors are used, as specified in

Table 10.

3. IPORT includes full operating current of switching regulator controller.

4. The PD interface includes dual-level input current limit. At turn-on, before the HSO load capacitor is charged, the

current limit is set at the inrush level. After the capacitor has been charged within ~1.25 V of VNEG, the operating

current limit is engaged. This higher current limit remains active until the UVLO lower limit has been tripped or until the

hotswap switch is sufficiently current-limited to cause a foldback of the HSO voltage.

5. See application note, “AN956: Using the Si3402-B PoE PD Controller in Isolated and Non-Isolated Designs” for more

information.

6. Applies to non-isolated applications only (VOUT on schematic in Figure 1).