
V1.0 Dec 2006
Data Sheet
Ag8100
Power-Over-Ethernet Module
7. Typical Recommendations
Figure 8 gives an example of the tracking needed for the Ag8100. R1, R2 and R3 are
optional components, but C1 needs to be positioned close to the output pins of the Ag8100
as possible to minimise the current loop. The thermal performance of the Ag8100 can be
improved by increasing the surface area of the track +VDC, -VDC and Thermal Ground.
RC
ADJ
CP
Input from
Bridge Rectifiers
VIN-
VIN+
RA
Ag8100
1
* Heat dissipation of the Ag8100 can be improved by increasing the surface area of the +VDC, -VDC and Thermal Ground tracks.
*
*
Output
Voltage
C1
-VDC
+VDC
Figure 8: Typical Layout
8. Operating Temperature Range
Because the Ag8100 is a power component, it will generate heat, so it is important that this
be taken into consideration at the design stage.
The heart of the Ag8100 is a DC/DC converter, which like any other power supply will
generate heat. The amount of heat generated by the module will depend on the load it is
required to drive and the input voltage supplied by the PSE. The information shown within
this section of datasheet is referenced to a nominal 48Vdc input voltage supplied by the
PSE.
The Ag8100 has a maximum ambient operating temperature of 70
O
C see Figure 10,
Figure 11 & Figure 12. These results are in still air without any heatsinking, the
performance of the Ag8100 can be improved by forcing the airflow over the part or by
using a heatsink (see the Ag8100 application note on heatsinking for more information).
The Ag8100 has built-in thermal protection, to prevent the module from being damaged if
operated beyond its power / temperature specification. If the thermal protection circuit is
activated then the DC/DC converter will shut down and will remain off until the input
voltage is removed and reapplied. In shut down mode the Ag8100 input current will be less
than 5mA, which is below the PSE output hold current. The PSE will assume that the
Ag8100 has been disconnected and will switch its output off and will return to testing for a
Silver Telecom 2006
11