ltc4267cgn-1 Linear Technology Corporation, ltc4267cgn-1 Datasheet - Page 18

• Manufacturer Part Number: ltc4267cgn-1
• Description: Power Over Ethernet Ieee 802.3af Pd Interface With Integrated Switching Regulator
• Manufacturer: Linear Technology Corporation

LTC4267-1
designer should determine which power category the PD
falls into and then select the appropriate value of R
from Table 2. If a unique load current is required, the value
of R
where I
classifi cation and is given in the electrical specifi cations.
The R
grading the overall accuracy of the classifi cation circuit.
18
APPLICATIO S I FOR ATIO
R
CLASS
CLASS
CLASS
IN_CLASS
can be calculated as:
= 1.237V/(I
resistor must be 1% or better to avoid de-
is the LTC4267-1 IC supply current during
U
DESIRED
Figure 10. PD Front End with Isolation Transformer, 2nd Schottky Diode Bridge
U
– I
IN_CLASS
W
)
U
CLASS
Resistor power dissipation will be 50mW maximum and
is transient so heating is typically not a concern. In order
to maintain loop stability, the layout should minimize
capacitance at the R
can be disabled by fl oating the R
should not be shorted to V
LTC4267-1 classifi cation circuit to attempt to source very
large currents and quickly go into thermal shutdown.
CLASS
node. The classifi cation circuit
PORTN
CLASS
as this would force the
pin. The R
CLASS
42671f
pin