PEM1212 INFOMART IT SOLUTIONS, PEM1212 Datasheet - Page 2

• Manufacturer Part Number: PEM1212
• Description: 55T6940
• Manufacturer: INFOMART IT SOLUTIONS

Specifications of PEM1212

• Rohs Compliant: YES

FUNCTIONAL DESCRIPTION
www.poweredethernet.com
F.1. Inputs
The PEM1200 is compatible with all IEEE 802.3af compliant Power Sourcing Equipment (PSE) and supports the different power injection options of
Data/Signal pair (Mode A) or Spare Pair (Mode B). See Figure 2 – Typical System Configuration. As per IEEE 802.3af, it is specified that the PSE does not
apply power to the both outputs at the same time i.e. 4 pair injection. (Refer to IEEE802.3af standards for more information).
The PEM1200 provides for external input bridge rectifiers for improved system design flexibility, and distribution of heat generation. As an example, a system
designer wanting to provide two RJ45 inputs, both of which are PoE enabled, but use only one PEM1200 module to save costs. Another advantage is that this
allows the system designer to control the type and costs of the input rectification diodes.
Figure 2 – Typical System Configuration
In Mode A – Signal Pair injection, the signal lines carry both data and power. In Mode B – Spare Pair injection, the Signal pair carries only data, and the spare
pair carries power.
F.2. Powered Device (PD) Signature and Power Classification
When the PEM1200 is connected to a Cat 5e or greater Ethernet cable from an IEEE 802.3af compliant Power Sourcing Equipment (PSE), Endspan or
Midspan, it will automatically present a Powered Device (PD) signature to the PSE, as and when requested. The PSE will then recognise that a PD is
connected to that line and supply power. With the growing emphasis on “Green Power”, in the latest standard, IEEE has stressed for PDs to implement the
IEEE 802.3af Power Classification system to ensure correct provisioning of power from the PSE. To help in proper power level provisioning and improved
power management, the IEEE 802.3af standard provides for PDs to inform the PSE their required power levels via a Class system. The classes are defined
as per Table 1 below. The PEM1200 allows for programming the Class by placing a 1/16W or greater and 1% tolerance resistor detailed in Table 1.
Important :
F.3. Isolation
IEEE802.3af section 33.4.1 calls for a Powered Device (PD) to meet safety isolation requirement by meeting the electrical strength test of IEC 60950 sub
clause 6.2. Infomart’s® PoweredEthernet™ PEM1200 modules meet or exceed 1500V impulse test. This is also referred to as ‘Hi Pot Test’, ‘Flash Tested’,
‘Withstand Voltage’, ‘Proof Voltage’, ‘Dielectric Withstand Voltage’ & ‘Isolation Test Voltage’.
by
IEEE 802.3af COMPLIANT POWER
SOURCING EQUIPMENT (PSE)
(48V)
PSE
Do not connect Pin 4 to Pin 5 at any time. Do not connect Pins 4 and 5 and 6 at the same time. Connect Pin 5 only to
Pin 6 and only as per Table 1. Pin 5 and 6 may be left unconnected for default Class 0 but is not recommended.
Table 1 – Power Classification programming
PoE Power Class
0
1
2
3
4
RX
TX
+/-
+/-
+
-
Reserved for 802.3at
Required PD Power
0.44W ~ 12.95W
6.49W ~ 12.95W
0.44W ~ 3.84W
3.84W ~ 6.49W
2
4
5
1
3
6
7
8
SPARE PAIR
SPARE PAIR
SIGNAL PAIR
SIGNAL PAIR
DATA /
DATA /
PEM1200_11G_R0-8 (DRAFT)
4
5
1
2
3
6
7
8
Pin 4 (Vin –) and Pin 6 (CP2)
POWERED DEVICE (PD)
1/16W or greater and 1% tolerance resistor between
Do not connect
Reserved
90k9kΩ
280kΩ
143kΩ
RX
TX
-
~
~
-
+
~
~
Pin 5 (CP1) and Pin 6 (CP2)
Any value 10KΩ to 100 KΩ
Power Over Ethernet PD Module
+
Do not connect
Do not connect
Do not connect
Reserved
PEM1200 SERIES
VIN+
VIN-
PEM1200
+VDC
-VDC
DC
OUTPUT
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