PM8800ATR STMicroelectronics, PM8800ATR Datasheet - Page 16
PM8800ATR
Manufacturer Part Number
PM8800ATR
Description
IC POE-PD PWM CTLR 16-HTSSOP
Manufacturer
STMicroelectronics
Datasheet
1.PM8800ATR.pdf
(35 pages)
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
PM8800ATR
Available stocks
Company
Part Number
Manufacturer
Quantity
Price
Company:
Part Number:
PM8800ATR
Manufacturer:
ON
Quantity:
300 000
Part Number:
PM8800ATR
Manufacturer:
ST
Quantity:
20 000
PD interface
5
5.1
16/35
PD interface
Detection
In power over Ethernet systems, the PSE senses the connection to detect whether an IEEE
802.3af compatible device is plugged to the cable termination by applying a small voltage
(2.7 to 10 V) on the Ethernet cable and measuring in two successive steps the equivalent
resistance. During this phase, the Powered Device must present a resistance between
23.75 kΩ and 26.25 kΩ
PM8800A integrates a 24.5 kΩ signature resistor to simplify the design of PoE powered
Device appliances and to reduce the overall component count.
Signature resistor is in series to a pass transistor (see
resistor itself upon completion of the detection phase.
The value of the integrated detection resistance has been selected taking into account also
the diode bridges typical voltage drop.
During detection, most of the circuits inside the PM8800A are disabled to minimize the
offset current.
Figure 7.
PM8800A: reference schematic of the integrated 24.5 kΩ and resistor
disable logic
VSS
VIN
11.5V
PM8800 A
+
-
Figure
24.5k
7) used to disconnect the
PM8800A