PTB48540AAH Datasheet, PDF (2/12 Pages) Texas Instruments – 10-W Power-Over-Ethernet Isolated Power Module Assembly

PTB48540 Series
Not Recommended for New Designs
10-W Power-Over-Ethernet Isolated
Power Module Assembly
SLTS224B – APRIL 2004 – REVISED JULY 2004
Ordering Information
Output Voltage (PTB48540❒xx) Package Options (PTB48540x❒❒)
Code
Voltage
A
5V
B
3.3 V
C
12 V
Code
AH
AS
Description
Horiz. T/H
SMD, Standard ⁽²⁾
Pkg Ref. ⁽¹⁾
(EUP)
(EUQ)
Notes: (1) Reference the applicable package reference drawing for the dimensions and PC board layout
(2) “Standard” option specifies 63/37, Sn/Pb pin solder material.
Pin Descriptions
–V_OUT: This is the negative output from the module, with
respect to +Vout. Both the +Vout and –Vout terminals are
isolated from the Ethernet input, and used to power the
PD appliance. When this pin is connected to the PD appli-
ance common, a positive supply voltage is produced at
+Vout.
V_OUT Adj: By connecting a single resistor to this pin, the
regulated output voltage may be adjusted/trimmed by up
to ±10 % from the original set-point value. If no adjust-
ment is desired, this pin should be left open circuit.
+V_OUT: This is the positive output from the module with
respect to –Vout, and is used to power the PD appliance.
By connecting this pin to the PD appliance common, a
negative supply voltage will be produced at –Vout.
Input Ref: This pin provides access to the –Vin of the
internal DC/DC converter, and is the 0-VDC reference
for the ‘Output Inhibit’ control.
Detect A: This is a control input that is normally left open
circuit. The module incorporates an internal 24.9-kΩ
resistor, between the ‘Detect A’ and ‘Detect B’ pins. This
provides the PD with a correct “valid device” detection
resistance for the PSE. By placing an external resistor
between the ‘Detect A’ and ‘Detect B’ pins (in parallel with
the internal 24.9-kΩ resistor) the module can be made to
identify itself as a “non-valid device.”
Detect B: This pin is used in conjunction with the ‘Detect A’
input only when it is desired for the PD to communicate
a “non-valid” device signature to the PSE (see ‘Detect A’
description). ‘Detect B’ is also the rectified DC output from
the module’s internal diode bridges, and represents the
positive DC input to the module’s DC/DC converter.
Connecting an external capacitor between this pin and the
‘Input Ref’ pin (0 V), adds more filter capacitance across
the input of the DC/DC converter.
Data Line A/B: These are the main inputs from which
the module obtains DC input power from the Ethernet
connector. The connection of these inputs to the Ethernet
connections must be via an IEEE 802.3af compliant signal
tranformer, that is designed for use in a PoE application.
This is necessary to preserve the integrity of the Ethernet
data traffic. Consult the example application for further
information.
Spare Line A/B: These are alternative inputs from which
the module may obtain DC input power. In a PoE appli-
cation, ‘Spare Line A’ may be directly connected to pins 4
& 5, and ‘Spare Line B’ to pins 7 & 8 of an Ethernet RJ-45
connector. These connections are not used for data trans-
mission.
Class A/B: The control inputs ‘Class A’ and ‘Class B’ allow
the PD Class to be programmed from the module. The
module incorporates an internal 4.42-kΩ resistor between
the ‘Class A’ and ‘Class B’ inputs. This corresponds
to a default “Class 0” PD classification signature being
sent to the PSE. By adding an external resistor across
these pins, the module can be programmed to other PD
classifications. For further information, consult the PD
class reference table in the application notes.
Output Inhibit: This is an open-collector (or open-drain)
negative logic input. Applying a low-level voltage to this
input, with respect to the ‘Input Ref’ pin, turns off the
DC output voltage from the module. If the pin is left
open-circuit, the module will operate as normal, pro-
ducing an output voltage whenever it is connected to a
valid PoE input source.
For technical support and further information visit http://power.ti.com