2
Quick start proceDure
Demonstration circuit 2541A is easy to set up for evaluat-
ing the performance of the LTC4279. Refer to Figure 1 for
proper measurement equipment setup, Table 1 for jumper
and supply settings, and follow the procedure below.
1) Select the evaluation PSE Type as shown in Table 1 and
set the jumpers accordingly.
2) Connect a power supply with the positive to AGND (J3)
and negative to VEE (J4).
3) Ramp up the supply to the recommended values speci-
fied in Table 1 for the configured mode. VEE LED1 will
turn on when the board is powered.
4) Connect test measurement probes across VPORT+
and VPORT– for 2-pair measurements, and optionally
additional test measurement probes across DATA2+
and DATA2– for 4-pair measurements.
5) Connect a PD with a Cat5e Ethernet cable to RJ45
connector J1. PORT PWR LED2 will turn on if the port
power is on.
6) Connect a 10BASE-T, 100BASE-T or 1000BASE-T PHY
data source with an Ethernet cable to J2 for data testing
(optional).
Table 1. Example Jumper Settings and VEE Supply Range for the Various PSE Types (Note 1)
PSE TYPE
POWER MODE
(JP6)
PORT+ (JP1)/
PORT– (JP2)
MID
(JP3)
DUALPD
(JP4)
LEGACY
(JP5)
MAIN PS
IEEE 802.3at Type 1
(13W)
TYPE 1 (13W)
2-PAIR
LO/HI
LO
LO
45V to 57V
Legacy
TYPE 1 (13W)
2-PAIR
LO/HI
LO
HI
48V (Typical)
IEEE 802.3at Type 2
(25.5W)
TYPE 2 (25.5W)
2-PAIR
LO/HI
LO
LO
51V to 57V
LTPoE++ (38.7W)
LTPoE++ (38.7W)
4-PAIR
LO/HI
LO
LO
51V to 57V
LTPoE++ (52.7W)
LTPoE++ (52.7W)
4-PAIR
LO/HI
LO
LO
51V to 57V
Dual PD
LTPoE++ (52.7W)
4-PAIR
LO/HI
HI
LO
51V to 57V
LTPoE++ (70W)
LTPoE++ (70W)
4-PAIR
LO/HI
LO
LO
54.75V to 57V
LTPoE++ (90W)
LTPoE++ (90W)
4-PAIR
LO/HI
LO
LO
54.75V to 57V
Note 1:
The application is not limited to these settings. See the LTC4279 data sheet pin descriptions.
