PM8800ATR STMicroelectronics, PM8800ATR Datasheet - Page 20

• Manufacturer Part Number: PM8800ATR
• Description: IC POE-PD PWM CTLR 16-HTSSOP
• Manufacturer: STMicroelectronics

Specifications of PM8800ATR

• Applications: Power Over Ethernet (PoE)
• Interface: IEEE 802.3af
• Voltage - Supply: 10 V
• Package / Case: 16-TSSOP Exposed Pad, 16-eTSSOP, 16-HTSSOP
• Mounting Type: Surface Mount
• For Use With: 497-6366 - BOARD EVAL FOR PM8800A
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 497-6897-2; PM8800ATR

PD interface
5.5
20/35
In the following picture a typical start sequence that can be observed in real circuits.
Figure 11. Typical start up sequence
Ch1 = 5 Vout, Ch2 = VSS - GND, Ch3 = Vcc, Ch4 = I input
Depending on the application, care must be put on the choice of the inrush current limit to
avoid that the voltage drop on the external Ethernet cable will cause UVLO conditions during
the charging phase of the bulk capacitor.
It is recommended to select this voltage drop (20 Ω max for 100 m of cable x I inrush) to be
lower than the UVLO hysteresis ( 7 V) in order to avoid hiccup turn on.
Continuos current limitation
PM8800A provide a default continuos current limitation of 440 mA. This is achieved by
leaving the pin DCCDL floating. A different DC current limit can be set by connecting a
resistor between DCCL and VSS whose value can be obtained by the following equation:
R
DC
[
kΩ
]
=
---------------------- -
I
DC
11200
[
mA
]
PM8800A