Linear Technology DC1249A - LTC4267-3 PD, 37-57V input, 3.3V@ 3A out DC1249A DC1249A 数据表
产品代码
DC1249A
QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 1249
POE TO 3.3V@3.0A ISOLATED
1
LTC4267CDHC-3
DESCRIPTION
Demonstration circuit 1249 is a PoE to 3.3V@3.0A
Isolated Converter featuring the LTC4267CDHC-3.
The board provides a complete IEEE 802.3af
power device (PD) interface and isolated 3.3V
power supply solution for use in Power-over-
Ethernet (PoE) applications in a very small printed
circuit board footprint.
Isolated Converter featuring the LTC4267CDHC-3.
The board provides a complete IEEE 802.3af
power device (PD) interface and isolated 3.3V
power supply solution for use in Power-over-
Ethernet (PoE) applications in a very small printed
circuit board footprint.
The LTC4267-3 integrates the 25kΩ signature re-
sistor, classification current source, thermal over-
load protection, signature disable and power good
signal along with an undervoltage lockout opti-
mized for use with the IEEE required diode bridge.
The precision dual level input current limit allows
sistor, classification current source, thermal over-
load protection, signature disable and power good
signal along with an undervoltage lockout opti-
mized for use with the IEEE required diode bridge.
The precision dual level input current limit allows
the LTC4267-3 to charge load capacitors and in-
terface with legacy PoE systems.
terface with legacy PoE systems.
The LTC4267-3 combines the above features with
a current mode switching controller designed for
driving a N-channel MOSFET. It features pro-
grammable slope compensation, soft-start, and
constant frequency operation, minimizing electrical
noise even with light loads.
a current mode switching controller designed for
driving a N-channel MOSFET. It features pro-
grammable slope compensation, soft-start, and
constant frequency operation, minimizing electrical
noise even with light loads.
Design files for this circuit board are available.
Call the LTC factory.
Call the LTC factory.
Table 1.
Performance Summary (T
A
= 25°C)
PARAMETER
CONDITION
VALUE
Turn-on Voltage
Input from PSE
-37V
Maximum Turn-off Voltage
Input from PSE, PD switch turns off
-31V
Minimum operating voltage
I
OUT
= 3A
-33V
Power Converter Input operating range
V
OUT
= 3.3V, I
OUT
= 0 to 3.0A
-37V to -57V
Maximum Input Current
Input from PSE, PD high level current limit
375mA, typical
Maximum Output Current
V
OUT
= 3.3V
3.0A
Output Voltage
V
IN
= 48VDC from PSE, I
OUT
= 3.0A
3.3V, typical
Line (0% to 100% full load)
2%
Output Regulation
Load (0% to 100% of rated full load)
2%
QUICK START PROCEDURE
Demonstration circuit 1249 is easy to set up to
evaluate the performance of the LTC4267-3. For
proper equipment setup, refer to figure 1 and fol-
low the procedure below:
evaluate the performance of the LTC4267-3. For
proper equipment setup, refer to figure 1 and fol-
low the procedure below:
1. With the power source to the PSE turned off,
connect the input power supply to the board
through the J1 filtered Ethernet connector.
through the J1 filtered Ethernet connector.
2. In addition to a PSE, the DC1249 board can
be powered by an alternate input power supply