Not Recommended for New Designs
PTB48540 Series
10-W Power-Over-Ethernet Isolated
Power Module Assembly
SLTS224B – APRIL 2004 – REVISED JULY 2004
Features
• Input Voltage Range:
36 V to 57 V
• 10 W Output
• IEEE Std. 802.3af Compliant
(for PoE-PD Interface)
• 85 % Efficiency
• Low Profile (9 mm)
• Output Voltage Trim/Adjust
• Under-Voltage Lockout
• Input Transient Suppressor
• Internal EMI Filter
• Meets FCC Class B Radiated &
Class A Conducted
• Output Inhibit Control
• Short Circuit Protection
• Over Temperature Shutdown
• 1500 VDC Isolation
• Safety Approvals (Pending):
UL 60950, cUL 60950, EN60950
Description
Pin Assignments
The PTB48540 series of power modules is specifically designed to provide
an isolated, low-voltage power source to
a remote Powered Device (PD) in PowerOver-Ethernet (PoE) applications. These
modules are rated 10 W and incorporate
all the necessary interface requirements
to comply with IEEE Std. 802.3af, for
managing the input power to the PD from
the PoE Power Sourcing Equipment
(PSE). This includes PD detection and
PD classification current signatures
required for the PSE. The modules are
compatible with PD classifications, class 0
through class 3.
In addition to a fully integrated DC/DC
converter, each PTB48540 power module
incorporates internal input diode bridges
to support both Data Line and Spare Line
pair standard Ethernet power connections, an integral transient suppressor
for input over-voltage protection, and
an EMI filter to ensure noise compatibility with Ethernet data signals.
Other features include an input undervoltage lockout (UVLO), over-current
and short-circuit protection, an output
voltage adjust/trim, and over-temperature
protection. An “Output Inhibit” control
allows the output voltage to be turned
off to support an idle condition or power
saving mode. The output voltage options
are for 3.3-V, 5-V, or 12-V output. The
target applications are small low-power
remote IP appliances, such as security card
readers and cameras, test dongles, and IP
phone consoles.
–VOUT
Output Inhibit
Class A
Class B
Product Top View
13
12
11
PoE-PD
Interface Switch
(TPS2375)
1
10
Data Line A
9
Data Line B
Transient
Suppression
8
Spare Line A
Data/Spare Line
Bridge Rectifiers
7
Spare Line B
EMI
Filter
For technical support and further information visit http://power.ti.com
DC/DC
Converter
4
5
6
Detect B
3
Detect A
+VOUT
2
Input Ref
VOUT Adj
Pin
1
2
3
4
5
6
7
8
9
10
11
12
13
Function
–Vout
Vout Adj
+Vout
Input Ref
Detect A
Detect B
Spare Line B
Spare Line A
Data Line B
Data Line A
Class B
Class A
Output Inhibit *
Shaded functions indicate signals
electrically common with the input.
* Denotes negative logic:
Open = Normal operation
Low (Input Ref) = Output Off
Not Recommended for New Designs
PTB48540 Series
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
A
B
C
Code
AH
AS
Voltage
5V
3.3 V
12 V
Description
Horiz. T/H
SMD, Standard (2)
Pkg Ref.
(EUP)
(EUQ)
(1)
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
–VOUT: 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 appliance common, a positive supply voltage is produced at
+Vout.
VOUT 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 adjustment is desired, this pin should be left open circuit.
+VOUT: 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 application, ‘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 transmission.
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, producing an output voltage whenever it is connected to a
valid PoE input source.
For technical support and further information visit http://power.ti.com
Not Recommended for New Designs
PTB48540 Series
10-W Power-Over-Ethernet Isolated
Power Module Assembly
Specifications
SLTS224B – APRIL 2004 – REVISED JULY 2004
(Unless otherwise stated, T a =25°C, Vin =48V (1), and Io =Iomax)
PTB48540 SERIES
Characteristic
Symbol
Conditions
Output Current
Io
Over Vin range
Input Voltage Range
Set Point Voltage Tolerance
Temperature Variation
Line Regulation
Load Regulation
Total Output Voltage Variation
Vin
Vo tol
Regtemp
Regline
Regload
∆Votot
Over Io Range
Efficiency
η
Vo Ripple (pk-pk)
Transient Response
Vr
ttr
∆Vtr
Output Voltage Adjust
Current Limit Threshold
Switching Frequency
Under-Voltage Lockout
Vadj
Ilim
ƒs
UVLO
Output Inhibit (Pin 13)
Input High Voltage
Input Low Voltage
Input Low Current
VIH
VIL
IIL
Standby Input Current
External Output Capacitance
Iin standby
Cout
pins 13 & 4 connected
Internal Input Capacitance
Cin
Detection Resistance
Classification Current
Operating Temperature Range
Over Temperature Protection
Rdetect
Iclass
Ta
OTP
Vin < UVLO threshold
Vin > UVLO threshold
2.7 V ≤ Vin ≤ 10.1 V
14.5 V ≤ Vin ≤ 20.5 V
Over Vin range
Measured at pin 7
Isolation Voltage
Capacitance
Resistance
Solder Reflow Temperature
Storage Temperature
Reliability
Treflow
Ts
MTBF
Mechanical Shock
—
Mechanical Vibration
—
Weight
Flammability
—
—
PTB48540A (5 V)
PTB48540B (3.3 V)
PTB48540C ( 12 V)
–40 ≤Ta ≤ +85 °C, Io =Iomin
Over Vin range
Over Io range
Includes set-point, line, load,
–40 ≤Ta ≤ +85 °C
PTB48540C (12 V)
PTB48540A
(5 V)
PTB48540B (3.3 V)
20 MHz bandwidth
1 A/µs load step, 50 % to 100 % Iomax
Vo over/undershoot
Vo ≤ 5 V
Vo =12 V
Vin = 42 V, ∆Vo = –1 %
Over Vin range
Vin rising
Vin falling
Referenced to Input Ref (pin 4)
Vo ≤ 5 V
Vo = 12 V
Threshold
Hysterisis
Input–output
Surface temperature of module body or pins
—
Per Bellcore TR-332
50 % stress, Ta =40 °C, ground benign
Per Mil-Std-883D, method 2002.3,
1 mS, half-sine, mounted to a fixture
Mil-Std-883D, Method 2007.2
Pkg EUP
20-2000 Hz, soldered to PC
Pkg EUQ
—
Materials meet UL 94V-0
Min
Typ
Max
0.1 (2)
0.1 (2)
0.1 (2)
36
—
—
—
—
—
—
—
—
—
±1
±0.2
±1
±5
±1.5
2
3
0.85
57 (1)
±2
—
—
—
±3
Units
—
—
—
—
—
—
—
—
—
200
—
30
85
82
79
50
100
±150
±200
±10
150
300
40
32
—
—
—
—
—
—
—
—
—
400
42
—
4.5
–0.2
—
—
0 (4)
0 (4)
0.05
5
23.75
2
–40
135
—
1500
—
10
—
–40
4
—
—
–2
1
—
—
0.1
7
24.9 (5)
2.5 (6)
—
—
20
—
1,100
—
—
—
—
Open (3)
+0.8
—
—
1000
330
0.12
—
26.25
3
+85 (7)
—
—
—
—
—
235 (8)
+125
—
—
500
—
G’s
—
—
—
20
7.5
12
—
—
—
G’s
A
VDC
%Vo
%Vo
mV
mV
%Vo
%
mVpp
µs
mV
%Vo
%Iomax
kHz
V
V
mA
mA
µF
µF
kΩ
mA
°C
°C
V
pF
MΩ
°C
°C
106 Hrs
grams
Notes: (1) The input voltage Vin is applied and measured between ‘Data Line A’ (pin 10) and ‘Data Line B’ (pin 9), or between ‘Spare Line A’ (pin 8) and ‘Spare
Line B (pin 7). These inputs accept either polarity.
(2) The DC/DC converter will operate at no load with reduced specifications.
(3) The Output Inhibit (pin 13) is referenced to ‘Input Ref ’ (pin 4) and has an internal pull-up. If it is left open circuit the converter will operate when
input power is applied. The open-circuit voltage is typically 5 V. Refer to the application notes for interface considerations.
(4) An output capacitor is not required for proper operation.
(5) This is the default for a “Valid Device” PD detection signature.
(6) This is the default for a “Class 0” PD classification signature.
(7) See Safe Operating Area curves or contact the factory for the appropriate derating.
(8) During the reflow of the SMD package version do not elevate the peak temperature of the module, pins, or internal components above the stated maximum.
For technical support and further information visit http://power.ti.com
Not Recommended for New Designs
Typical Characteristics
PTB48540 Series
10-W Power-Over-Ethernet Isolated
Power Module Assembly
PTB48540B; Vo =3.3 V
SLTS224B – APRIL 2004 – REVISED JULY 2004
PTB48540A; Vo =5 V
(See Note A)
Efficiency vs Load Current
Efficiency vs Load Current
100
42 V
48 V
57 V
70
80
42 V
48 V
57 V
70
60
60
50
0.5
1
1.5
2
2.5
3
Output Ripple vs Load Current
0.4
0.8
1.2
1.6
2
0
Output Ripple vs Load Current
80
80
60
42 V
48 V
57 V
40
20
VIN
Ripple - mV
40
20
0
2.5
3
Power Dissipation vs Load Current
0.4
0.8
1.2
1.6
2
0
1.5
42 V
48 V
57 V
1
Pd - Watts
1
VIN
VIN
Pd - Watts
1.5
0
3
0
0.4
Iout - Amps
0.8
1.2
1.6
0
2
60
50
40
30
80
Airflow
70
400LFM
200LFM
100LFM
Nat conv
60
50
40
30
20
20
1.0
1.5
Iout (A)
2.0
2.5
3.0
0.8
90
Ambient Temperature (°C)
400LFM
200LFM
100LFM
Nat conv
Ambient Temperature (°C)
Airflow
70
0.6
Safe Operating Area (See Note B)
90
80
0.4
Iout - Amps
Safe Operating Area (See Note B)
Safe Operating Area (See Note B)
0.5
0.2
Iout - Amps
90
0.0
42 V
48 V
57 V
1
0
0
2.5
1.5
0.5
0.5
0.5
2
0.8
2
2
42 V
48 V
57 V
0.6
2.5
VIN
2
0.4
Power Dissipation vs Load Current
Power Dissipation vs Load Current
2.5
1.5
0.2
Iout - Amps
2.5
1
40
Iout - Amps
3
0.5
42 V
48 V
57 V
0
0
Iout - Amps
0
60
20
0
2
0.8
VIN
Ripple - mV
Ripple - mV
42 V
48 V
57 V
0.6
Output Ripple vs Load Current
80
60
0.4
100
VIN
1.5
0.2
Iout - Amps
100
1
70
Iout - Amps
100
0.5
42 V
48 V
57 V
50
0
Iout - Amps
0
VIN
80
60
50
0
Pd - Watts
Efficiency - %
80
90
VIN
Efficiency - %
Efficiency - %
100
90
VIN
(See Note A)
Efficiency vs Load Current
100
90
Ambient Temperature (°C)
PTB48540C; Vo =12 V
(See Note A)
80
Airflow
70
400LFM
200LFM
100LFM
Nat conv
60
50
40
30
20
0.0
0.4
0.8
1.2
Iout (A)
1.6
2.0
0.0
0.2
0.4
0.6
0.8
Iout (A)
Note A: Characteristic data has been developed from actual products tested at 25°C. This data is considered typical data for the converter.
Note B: SOA curves represent the conditions at which internal components are at or below the manufacturer’s maximum operating temperatures. Derating limits apply to
modules soldered directly to a 4 in. × 4 in. double-sided PCB with 1 oz. copper.
For technical support and further information visit http://power.ti.com
Not Recommended for New Designs
Application Notes
PTB48540 Series
Operating Features of the PTB48540
Series Power-Over-Ethernet Modules
Overview
Figure 1-1 shows the block diagram of the PTB48540
series of Power-over-Ethernet (PoE) modules. Input
power to the module can be supplied through either the
Data Line A/B or Spare Line A/B associated Ethernet
connections. A diode bridge associated with each of these
input pairs allows the input source to be supplied in either polarity. A transient suppressor, located across the
common output of the diode bridges, protects the module
against power surges.
The input power to the internal DC/DC converter is
controlled by the TPS2375 IC. This IC is a power interface switch, specifically designed for use with PoE powered
devices. The IC provides the device detection, classification,
and current limiting control that is necessary for a powered
device (PD) to comply with the IEEE 802.af Standard.
The DC/DC converter input circuit includes an EMI
filter, which maintains the module in compliance with
CISPR 22 (EN5022); class ‘B’ for radiated, and class ‘A’
for conducted emissions.
PD Detection
Prior to power up, the PoE power sourcing equipment
(PSE) must detect a 24.9-kΩ “discovery” load resistance
from the PD. This default value of resistance is necessary for the PD to be recognized as a “valid device” by
the PSE. A 24.9-kΩ resistor is provided internally to the
PTB48540 modules. It is located across the ‘Detect A’
(pin 5) and ‘Detect B’ (pin 6) terminals. By placing an
external resistor across these pins (in parallel with the
internal 24.9-kΩ resistor), the module can be made to
communicate a “non-valid device” signature to the PSE.
A non-valid device is recognized by a resistance of less than
12 kΩ. Connecting a 16.9-kΩ external resistor between
the ‘Detect A’ and ‘Detect B’ pins creates an equivalent
resistance of 10 kΩ. This is sufficient to communicate a
non-valid device signature. The external resistor should
not be less than 16.9 kΩ as this increases power dissipation in the power interface IC.
PD Classification Signature
The PSE uses a classification current to determine the
maximum supply current that the PD is allowed to draw.
The classification current is sensed by the PSE when the
supply voltage to the PD is between 15 V and 20 V. The
classification current is set on the PTB48540 by a programming resistance. Table 1-1 gives the resistance values
Figure 1 1; Block Diagram of the PTB48540 Series Modules
Output Inhibit 13
Input Ref 4
Detect A 5
External
RDETECT
PD Detect
24.9 k
(Valid Device)
Detect B 6
1500 VDC
Isolation
Data Line A 10
Data Line B 9
Spare Line A 8
1
2
Spare Line B 7
3
4
Class B 11
External
RCLASS
DC/DC
Converter
TPS2375
PoE Interface
Class Select
4.42 k
(Class 0)
Class A 12
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ILIM
VDD
CLASS
NC
DETECT EN_DC
VEE
RTN
8
7
Inhibit
Adjust
2
VOUT Adj
+VIN
+VOUT
3
+ VOUT
–VIN
–VOUT
1
–VOUT
Input EMI Filter
6
5
Not Recommended for New Designs
Application Notes continued
PTB48540 Series
Table 1-1; PD Class Programming Resistance
PD
Class
PD Demand (watts)
Usage
Min
Max
Class Program
Resistance
External
Resistor
0
Default
0.44
12.95
4.42 kΩ
None
1
Optional
0.44
3.84
950 Ω
1.21 kΩ
2
Optional
3.84
6.49
543 Ω
619 Ω
3
Optional
6.49
12.95
360 Ω
392 Ω
4
Not Allowed
— Future Use —
252 Ω
267 Ω
for the different types of PD class defined in the IEEE
802.3af Standard. The power modules support the PD
classification protocol with a default ‘Class 0’ signature.
‘Class 0’ corresponds to a 4.42-kΩ programming resistance, which is set by an internal resistor located between
the ‘Class A’ (pin 12) and ‘Class B’ (pin 11) terminals. By
placing an external resistor across the Class A/B pins (in
parallel with the internal 4.42-kΩ resistor) the power
module can be made to communicate one of the alternate
classifications to the PSE. Consult Table 1-1 for the
external resistance values.
Under-Voltage Lockout
The UVLO prevents the internal DC/DC converter from
seeing an input voltage until the voltage applied to either
the ‘Data Line A/B’ or ‘Spare Line A/B’ pair of Ethernet
connections approaches 42 V. The UVLO threshold
correlates to a voltage between the ‘Detect B’ (pin 6) and
‘Class B’ (pin 11) terminals of approximately 39.3 V. Only
after the voltage applied from the Ethernet is above the
UVLO threshold is the module’s internal bus voltage
allowed to rise. The internal bus powers the DC/DC
converter and can be measured between the ‘Detect B’
(pin 6) and ‘Input Ref’ (pin 4) terminals.
Input Capacitance
In accordance with the IEEE 802.3af Standard, the
PTB48540 power modules provide an input capacitance
of 0.1 µF to the PSE when communicating the required
detection and classification signatures. Once fully powered (Vin ≥42 V), the PSE will see the combined input
capacitance of the EMI filter and DC/DC converter;
approximately 7 µF. This capacitance is sufficient to
operate the module’s internal DC/DC converter, and
satisfies the 5 µF minimum capacitance required by the
IEEE 802.3af Standard. For improved hold-up capability,
this input capacitance can be increased with an external
capacitor. Connect the anode of the external capacitor
to ‘Detect B’ (pin 6), and the cathode to the ‘Input Ref’
(pin 4). During power up the power interface IC limits
the inrush current for charging the input capacitance.
Additional capacitance increases the power dissipation in
the IC. For this reason the maximum recommended value
of external capacitance is 220 µF (100-V electrolytic).
Startup
Startup of the module in a PoE application consists of a
complex process of handshaking states between the module
and PSE. During the PD detection state the PSE uses a
low voltage (