SI3402-A-GM Silicon Laboratories Inc, SI3402-A-GM Datasheet - Page 16

• Manufacturer Part Number: SI3402-A-GM
• Description: IC POE PD LOW EMI SW REG 20VQFN
• Manufacturer: Silicon Laboratories Inc
• Type: Power over Ethernet Switch (PoE)r

Specifications of SI3402-A-GM

• Package / Case: 20-VQFN
• Applications: IP Phones, Power over LAN, Network Routers and Switches
• Internal Switch(s): Yes
• Current Limit: 470mA
• Voltage - Supply: 2.8 V ~ 57 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Product: PoE / LAN Solutions
• Supply Voltage (max): 57 V
• Supply Voltage (min): 2.8 V
• Power Dissipation: 1.2 W
• Operating Temperature Range: - 40 C to + 85 C
• Mounting Style: SMD/SMT
• Operating Temperature (min): -40C
• Operating Temperature Classification: Industrial
• Operating Temperature (max): 85C
• Rad Hardened: No
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Lead free / RoHS Compliant

Si3402
4. Pin Descriptions
16
9, Pad
Pin#
10
11
12
13
14
15
16
17
18
19
20
1
2
3
4
5
6
7
8
ISOSSFT
EROUT
VPOSS
PLOSS
VPOSF
Name
VNEG
RDET
VSSA
SSFT
VSS1
VSS2
SWO
VDD
HSO
RCL
SP2
SP1
CT2
CT1
FB
Error-amplifier output and PWM input; directly connected to opto-coupler in isolated application.
Soft-start output pin ramps voltage across external soft-start capacitor to allow switcher to ramp
output slowly.
5 V supply rail for switcher; provides drive for opto-coupler.
0.1 µF capacitor between this pin and VSSA for isolated applications.
Early power loss indicator; open drain output is pulled to VPOS when VPORT is applied.
Input pin for external precision detection resistor; also used for establishing absolute current
reference.
Hotswap switch output; connects to VNEG through hotswap switch.
Input pin for external precision classification resistor; float if optional RCLASS is unused.
Rectified high-voltage supply, negative rail. Must be connected to thermal PAD node (VNEG)
on package bottom. This thermal pad must be connected to VNEG (pin #9) as well as a 2 in
heat spreader plane using a minimum of nine thermal vias.
High-voltage supply input from spare pair; polarity-insensitive.
High-voltage supply input from spare pair; polarity-insensitive.
Rectified high-voltage supply, positive rail (force node)
High-voltage supply input from center tap of Ethernet transformer; polarity-insensitive.
High-voltage supply input from center tap of Ethernet transformer; polarity-insensitive.
Analog ground.
Rectified high-voltage supply, positive rail sense node.
Negative supply rail for switcher; externally tied to HSO.
Switching transistor output; drain of switching N-FET.
Negative supply rail for switcher; externally tied to HSO.
Regulated feedback input in non-isolated application.
Isolated mode soft start enable input. Tie to VDD for non-isolated applications. Connect a
Table 12. Si3402 Pin Descriptions (Top View)
ISOSSFT
EROUT
SSFT
VDD
1
2
3
4
20
5
19
6
Rev. 1.1
18
VNEG
(PAD)
7
17
8
16
9
Description
10
15
14
13
12
11
CT2
CT1
VPOSF
SP1
2