PTB48540CAS [TI]

1-OUTPUT 10W DC-DC REG PWR SUPPLY MODULE;


型号：	PTB48540CAS
厂家：	TEXAS INSTRUMENTS
描述：	1-OUTPUT 10W DC-DC REG PWR SUPPLY MODULE 输出元件
文件：	总12页 (文件大小：435K)
中文：	中文翻译
下载：	下载PDF数据表文档文件

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

• Internal EMI Filter

• Meets FCC Class B Radiated &

Class A Conducted

• Output Inhibit Control

• 10 W Output

• IEEE Std. 802.3af Compliant

(for PoE-PD Interface)

• Short Circuit Protection

• Over Temperature Shutdown

• 1500 VDC Isolation

• 85 % Efficiency

• Low Profile (9 mm)

• Output Voltage Trim/Adjust

• Under-Voltage Lockout

• Input Transient Suppressor

• Safety Approvals (Pending):

UL 60950, cUL 60950, EN60950

Description

Pin Assignments

The PTB48540 series of power mod-

ules is specifically designed to provide

an isolated, low-voltage power source to

a remote Powered Device (PD) in Power-

Over-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.

Pin Function

to support both Data Line and Spare Line

pair standard Ethernet power connec-

tions, an integral transient suppressor

for input over-voltage protection, and

an EMI filter to ensure noise compat-

ibility with Ethernet data signals.

Other features include an input under-

voltage 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

Vout Adj

+Vout

Input Ref

Detect A

Detect B

Spare Line B

Spare Line A

Data Line B

10 Data Line A

11 Class B

12 Class A

13 Output Inhibit *

Shaded functions indicate signals

electrically common with the input.

In addition to a fully integrated DC/DC

converter, each PTB48540 power module

incorporates internal input diode bridges

* Denotes negative logic:

Open = Normal operation

Low (Input Ref) = Output Off

Product Top View

13 12 11

PoE-PD

Interface Switch

(TPS2375)

10 Data Line A

–V_OUT

V_OUTAdj

+V_OUT

EMI

Filter

DC/DC

Converter

Data Line B

Spare Line A

Transient

Suppression

Spare Line B

Data/Spare Line

Bridge Rectifiers

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

SLTS224B – APRIL 2004 – REVISED JULY 2004

Ordering Information

Output Voltage

(PTB48540❒xx)

Package Options

(PTB48540x❒❒)

(1)

Code

Voltage

5 V

3.3 V

12 V

Code

Description

Horiz. T/H

SMD, Standard ⁽²⁾

Pkg Ref.

(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.

‘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.

_OUTAdj: 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.

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.

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.

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.

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.”

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.

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

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

SLTS224B – APRIL 2004 – REVISED JULY 2004

Specifications (Unless otherwise stated, T_a=25°C, V_in=48V ⁽¹⁾, and I_o=I_omax)

PTB48540 SERIES

Characteristic

Symbol

Conditions

Min

Typ

Max

Units

Output Current

I_o

Over V_inrange

PTB48540A (5 V)

PTB48540B (3.3 V)

PTB48540C ( 12 V)

0.1 ⁽²⁾

—

0.85

(1)

Input Voltage Range

Set Point Voltage Tolerance

Temperature Variation

Line Regulation

Load Regulation

Total Output Voltage Variation

V_in

Over I_oRange

—

0.2

—

VDC

%V_o

V_otol

Reg_temp

Reg_line

Reg_load

∆V_otot

–40 ≤T_a≤ +85 °C, I_o=I_omin

Over V_inrange

Over I_orange

Includes set-point, line, load,

–40 ≤T_a≤ +85 °C

1.5

Efficiency

PTB48540C (12 V)

—

PTB48540A

(5 V)

PTB48540B (3.3 V)

V_oRipple (pk-pk)

Transient Response

t_tr

∆V_tr

20 MHz bandwidth

1 A/µs load step, 50 % to 100 % I_omax

V_oover/undershoot

—

100

150

200

—

mV_pp

µs

V_o≤ 5 V

V_o=12 V

Output Voltage Adjust

Current Limit Threshold

Switching Frequency

V_adj

I_lim

ƒ_s

%V_o

%I_omax

kHz

V_in= 42 V, ∆V_o= –1 %

150

300

Over V_inrange

200

400

Under-Voltage Lockout

UVLO

_inrising

—

V_infalling

Output Inhibit (Pin 13)

Input High Voltage

Referenced to Input Ref (pin 4)

V_IH

V_IL

I_IL

4.5

—

–2

—

Open ⁽³⁾

+0.8

—

1000

330

–0.2

Input Low Voltage

Input Low Current

—

µF

Standby Input Current

External Output Capacitance

I_instandby

C_out

pins 13 & 4 connected

—

(4)

V_o≤ 5 V

(4)

V_o= 12 V

Internal Input Capacitance

C_in

V_in< UVLO threshold

V_in> UVLO threshold

0.05

0.1

0.12

—

µF

(5)

(6)

Detection Resistance

Classification Current

Operating Temperature Range

Over Temperature Protection

R_detect

I_class

2.7 V ≤ V_in≤ 10.1 V

14.5 V ≤ V_in≤ 20.5 V

Over V_inrange

23.75

–40

135

—

24.9

2.5

—

26.25

+85 ⁽⁷⁾

—

kΩ

°C

OTP

Measured at pin 7

Threshold

Hysterisis

Isolation Voltage

Capacitance

Resistance

Input–output

1500

—

1,100

—

MΩ

Solder Reflow Temperature

Storage Temperature

Reliability

T_reflow

Surface temperature of module body or pins

—

Per Bellcore TR-332

50 % stress, T_a=40 °C, ground benign

—

–40

—

235 ⁽⁸⁾

+125

—

°C

10⁶Hrs

MTBF

Mechanical Shock

—

Per Mil-Std-883D, method 2002.3,

1 mS, half-sine, mounted to a fixture

—

500

—

G’s

Mechanical Vibration

—

Mil-Std-883D, Method 2007.2

20-2000 Hz, soldered to PC

Pkg EUP

Pkg EUQ

—

G’s

7.5

Weight

Flammability

—

grams

Materials meet UL 94V-0

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

PTB48540 Series

Typical Characteristics

10-W Power-Over-Ethernet Isolated

Power Module Assembly

SLTS224B – APRIL 2004 – REVISED JULY 2004

PTB48540B; V_o=3.3 V (See Note A)

PTB48540A; V_o=5 V (See Note A)

PTB48540C; V_o=12 V (See Note A)

Efficiency vs Load Current

100

V_IN

42 V

V_IN

42 V

48 V

57 V

42 V

48 V

57 V

48 V

57 V

0.5

1.5

2.5

0.4

0.8

1.2

1.6

0.2

0.4

0.6

0.8

Iout - Amps

Output Ripple vs Load Current

100

V_IN

42 V

V_IN

42 V

48 V

57 V

42 V

48 V

57 V

48 V

57 V

0.5

1.5

2.5

0.4

0.8

1.2

1.6

0.2

0.4

0.6

0.8

Iout - Amps

Power Dissipation vs Load Current

2.5

V_IN

42 V

48 V

57 V

1.5

42 V

48 V

57 V

42 V

48 V

57 V

1.5

0.5

0.2

0.4

0.6

0.8

0.5

1.5

2.5

0.4

0.8

1.2

1.6

Iout - Amps

Safe Operating Area (See Note B)

Airflow

400LFM

200LFM

100LFM

Nat conv

400LFM

200LFM

100LFM

Nat conv

400LFM

200LFM

100LFM

Nat conv

0.0

0.4

0.8

1.2

1.6

2.0

0.0

0.2

0.4

0.6

0.8

0.0

0.5

1.0

1.5

2.0

2.5

3.0

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

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 neces-

sary 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 dissipa-

tion in the power interface IC.

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 ei-

ther 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 inter-

face 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 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 pro-

gramming resistance. Table 1-1 gives the resistance values

Figure 1 1; Block Diagram of the PTB48540 Series Modules

Output Inhibit 13

Input Ref

Detect A

PD Detect

24.9 k

(Valid Device)

External

R_DETECT

Detect B

1500 VDC

Isolation

Data Line A 10

DC/DC

Converter

Data Line B

Spare Line A

Spare Line B

TPS2375

PoE Interface

Adjust

V_OUTAdj

+ V_OUT

Inhibit

Input EMI Filter

V_DD

ILIM

+V_IN

+V_OUT

CLASS

DETECT EN_DC

VEE RTN

–V_IN

–V_OUT

Class B 11

External

Class Select

4.42 k

(Class 0)

R_CLASS

Class A 12

For technical support and further information visit http://power.ti.com

Not Recommended for New Designs

Application Notes continued

PTB48540 Series

Table 1-1; PD Class Programming Resistance

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 (<10 V) to detect the module’s “valid device”

resistance signature. This is followed by the classification

detection state where the PSE applies a voltage of 15 V

to 20 V to detect the module’s PD class. The PSE con-

tinues to raise the input voltage, but the input voltage to

the internal DC/DC converter is held at zero until the

voltage from the PSE approaches 42 V. At an input voltage

of 42 V or higher, the module’s power interface IC allows

the internal bus voltage to rise using a limited amount of

inrush current. Approximately 50 ms after the DC/DC

converter input filter capacitors are fully charged, the

module is able to produce a regulated output voltage.

PD Demand (watts)

Class

Class Program

External

Resistor

Usage

Default

Min

0.44

3.84

6.49

Max

12.95

3.84

Resistance

4.42 kΩ

950 Ω

None

1.21 kΩ

619 Ω

392 Ω

267 Ω

Optional

Not Allowed

6.49

543 Ω

12.95

360 Ω

— Future Use —

252 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 resis-

tance, 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.

Converter Over-Current Protection

The internal DC/DC converter has inherent protection

against an output load fault. Whenever its load current

exceeds the over-current protection threshold (see speci-

fication table) the converter momentarily turns its output

off. After a short period (<100 ms), the regulator will

attempt to power up again by executing a soft-start power

up. The converter will continue in a successive cycle of

shutdown, followed by soft-start power up until the load

fault is removed.

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.

When the DC/DC converter is powered from just the

Ethernet source, a load current above its rated output

(but below its over-current threshold) will likely activate

the over-current protection offered by the power interface

IC. This is especially at input voltages lower than 48 V.

Ethernet Over-Current Protection

Input Capacitance

Protection is also provided for the Ethernet power source

equipment (PSE). In event of a fault across the module’s

internal bus, the onboard power interface IC limits the

maximum current that may be drawn from the PSE to

no less than 405 mA. This prevents the DC/DC con-

verter from drawing excessive input current and also

safeguards against external faults that may occur across

the ‘Detect B’ (pin 6) and ‘Input Ref’ (pin 4) terminals.

Note: These terminals can be used to add capacitance to the

module’s internal bus.

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 pow-

ered (V_in≥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).

Load faults applied to the DC/DC converter’s output

will most often trigger the power interface IC’s protec-

tion mechanism prior to activating the converter’s own

current limit threshold. In these instances the power

interface IC will completely shut down the module’s inter-

nal bus. This is a latched condition. It is reset by the PoE

source when it attempts another power-up cycle after it

senses loss of the PD’s Maintain Power Signature (10 mA).

For technical support and further information visit http://power.ti.com

Not Recommended for New Designs

Application Notes

PTB48540 Series

Figure 2-1; Adjust Resistor Placement

Adjusting the Output Voltage of the PTB48540

Series of Power Over Ethernet Modules

PTB48540

The set-point output voltage of the PTB48540 series of

PoE modules may be adjusted (trimmed) by up to 10 %.

This is accomplished with the addition of a single exter-

nal resistor. For the input voltage range specified in the

data sheet, Table 2-1 gives the allowable adjustment range

for each model as V_o(min) and V_o(max).

+V_OUT

(R₁)

Adjust Dn

V_OUTAdj

Adjust Up: An increase in the output voltage is obtained

by adding a resistor, R₂between pin 2 (V_outAdj), and

pin 1 (–V_out).

R₂

Adjust Up

Adjust Down: Add a resistor (R₁), between pin 2 (V_outAdj)

and pin 3 (+V_out).

–V_OUT

Refer to Figure 2-1 and Table 2-2 for both the placement and

value of the required resistor, (R₁) or R₂.

Table 2-2

The values of (R₁) [adjust down], and R₂[adjust up], can

also be calculated using the following formulas.

DC/DC CONVERTER ADJUSTMENT RESISTOR VALUES

Series Pt #

PTB48540B

PTB48540A

PTB48540C

(R₁)

56.2 (V_a– 1.225)

V_o– V_a

– R_s

kΩ

V_o(nom)

V_a(req’d)

3.3 V

5 V

12 V

2.95

3.0

3.05

3.1

3.15

3.2

3.25

3.3

3.35

3.4

3.45

3.5

3.55

3.6

3.65

•

(90.0)kΩ

(146.0)kΩ

(223.0)kΩ

(340.0)kΩ

(534.0)kΩ

(923.0)kΩ

(2090.0)kΩ

68.845

V_a– V_o

R₂

– R_s

kΩ

Where,

V_o= Original output voltage

V_a= Adjusted output voltage

R_s= Internal resistance (Table 2-1)

Notes:

1190.0kΩ

501.0kΩ

272.0kΩ

157.0kΩ

88.4kΩ

42.5kΩ

9.7kΩ

1. Use only a single 1 % resistor in either the (R₁) or R₂

location. Place the resistor as close to the module as

possible.

2. Never connect capacitors to V_oadjust. Any capacitance

added to the V_oadjust control pin will affect the stability

of the module.

4.5

4.6

4.7

4.8

4.9

5.0

5.1

5.2

5.3

5.4

5.5

•

10.8

11.0

11.5

12.0

12.5

13.0

13.2

(258.0)kΩ

(364.0)kΩ

(541.0)kΩ

(895.0)kΩ

(1960.0)kΩ

3. The output power is limited to 10 W. If the output

voltage is increased, the maximum load current must

be derated according to the following equation.

V_a

I_o(max)

578.0kΩ

234.0kΩ

119.0kΩ

62.1kΩ

27.7kΩ

In any instance, the load current must not exceed the

converter’s rated current (See Table 2-1).

Table 2-1

DC/DC CONVERTER ADJUSTMENT PARAMETERS

(399.0)kΩ

(499.0)kΩ

(1110.0)kΩ

Series Pt #

Rated Current ³

PTB48540B

3 A

PTB48540A

PTB48540C

0.85 A

2 A

V_o(nom)

Vo(min)

Vo(max)

R_s(kΩ)

3.3 V

2.95 V

3.65 V

187

5 V

4.5 V

5.5 V

110

12 V

10.8 V

13.2 V

49.9

87.8kΩ

18.9kΩ

7.5kΩ

R₁= (Blue)

R₂= Black

For technical support and further information visit http://power.ti.com

Not Recommended for New Designs

Application Notes

PTB48540 Series

Figure 3-1

Using the Output Inhibit Control with the

PTB48540 Power-over-Ethernet Modules

The PTB48540 Power-over-Ethernet (PoE) modules

incorporate all the necessary interface requirements to

provide 10 W of regulated DC voltage from a recognized

Power-over-Ethernet source.

A- Detect -B

A- Class -B

+48 V

0 V

Data Line A

+5 V

+V_OUT

Data Line B

Input Ref

Adjust

–V_OUT

One of the operating features of these modules allows

the output voltage to be turned off, thereby placing the

module in an idle state. This may be useful for applica-

tions that have an alternative voltage source available,

such as a wall adapter.

PTB48540A

Spare Line A

0 V

Spare Line B

Output Inhibit

The “Output Inihibit” control is provided by pin 13. The

module functions normally with this pin open-circuit,

providing a regulated output voltage whenever a valid

source voltage is supplied from the Ethernet connection.

When a low voltage is applied to pin 13, with respect to

the “Input Ref” terminal (pin 4), the output is turned off.

Even though the Ethernet source is still present.

Q₁

BSS138

Alternate

On/Off

Contact/Switch

1 =Output Off

Figure 3-1 is an application schematic, which shows how

the “Output Inhibit” control may be used. Either a discrete

transistor (Q₁), or a contact switch may be used. The

“Output Inhibit” control pin has its own internal pull-up

(See notes 2 & 3). Table 3-1 gives the threshold require-

ments.

Turn-On Time: In the circuit of Figure 3-1, turning Q₁on

applies a low-voltage to pin 13 and disables the module

output. Correspondingly, turning Q₁off allows pin 13 to

be pulled high by an internal pull-up resistor. The module

produces a regulated output voltage within 60 ms. Figure

3-2 shows shows the output response of a PTB48540A

(5 V) following the turn-off of Q₁. The turn off of Q₁

corresponds to the drop in Q₁Vgs. Although the rise-time

of the output voltage is short (<5 ms), the indicated delay

time will vary depending upon the input voltage and the

module’s internal timing. The waveform was measured

with a 48 Vdc input voltage, and a 1.4 A resistive load.

When placed in the “Off” state, the standby current

drawn from the input source is typically reduced to 1 mA ³.

Table 3-1; Pin 13 Output Inhibit Control Parameters ¹

Parameter

Min

Typ

Max

Enable (V

)

4.5 V

—

Disable (V

)

0.8 V

[Open-Circuit]

5 V

o/c

[pins 13 & 4 connnected]

Figure 3-2

—

–1 mA

—

Vo (2V/Div)

Notes:

1. The Output Inhibit control uses Input Ref (pin 4) as its

0-V reference. All voltages specified are with respect to

the Input Ref pin.

Iin (0.2A/Div)

2. Use an open-collector device (preferably a discrete

transistor or switch) for the Output Inhibit input. A

pull-up resistor is not necessary. To turn the output

off, the control pin should be pulled low to less than

0.8 VDC.

Delay Time

Q1Vgs (10V/Div)

3. The module’s idle current is typically less than 1 mA.

This is below the minimum power signature (MPS)

current, required for the PoE source to continue providing

the PD with a source voltage. This will inevitably result

in the removal of the module’s input source. However,

the PSE will endevour to periodically re-apply input

power after detecting that the PD is still a valid device.

This cycle may be prevented by also modifying the

module’s ‘Detect’ signature resistance so that it reflects

an invalid device to the PSE.

HORIZ SCALE: 10ms/Div

For technical support and further information visit http://power.ti.com

Not Recommended for New Designs

Application Notes

PTB48540 Series

Using the PTB48540 Series Module in a

Power-Over-Ethernet (PoE) Application

The schematic of Figure 4-1 shows an example of how a

PTB48540 module may be connected to a PoE compliant

system. The connector J1 is the input from the PoE source.

appear as differential signals to each transformer. These

signals are isolated by the transformers, allowing the

Ethernet communication content to flow freely between

the connector and the powered device (PD) circuitry.

In a Power-over-Ethernet (PoE) application, the power

and high-frequency data signals share the same conductors

in the Ethernet cable. The data and power signals must

be separated using an IEEE 802.3af compliant PoE mag-

netic module.

The common-mode inductor, L1, is a popular addition

to off-the-shelf PoE magnetic modules. The inductor

provides additional rejection to common mode noise

currents, which may otherwise be present on either the

data or power signals.

The magnetic module incorporates the customary isola-

tion transformers, T1 and T2. The transformers each

include a center tap, across which the dc current from the

Ethernet power source equipment (PSE) is conveniently

extracted. The transmit and receive hf Ethernet data

The PTB48540 module complies with the PoE protocols,

provides the required isolation, and converts the raw

power from the PSE to a precision regulated 3.3-VDC

power source for the remote PD circuitry.

Figure 4-1; Power-Over-Ethernet Application Schematic

PoE Interface Transformer

H2019 (Pulse Engineering)

RJ-45

Ethernet

Connection

from PSE

TX1+

TXCT

TD+

TCT

TX1–

N/C

TD-

N/C

1:1

N/C

RD+

RX1+

RXCT

RX1–

RCT

RD-

1:1

Circuitry

A - Detect - B

- Class -

Data Line A

Data Line B

+3.3 V

+V_OUT

V_OUTAdj

–V_OUT

Input Ref

PTB48540B

Spare Line A

0 V

Spare Line B

Output Inhibit

For technical support and further information visit http://power.ti.com

PACKAGE OPTION ADDENDUM

www.ti.com

20-Jul-2012

PACKAGING INFORMATION

Status ⁽¹⁾

Eco Plan ⁽²⁾

Pb-Free (RoHS)

TBD

MSL Peak Temp ⁽³⁾

Samples

Orderable Device

Package Type Package

Drawing

Pins

Package Qty

Lead/

Ball Finish

(Requires Login)

PTB48540AAH

PTB48540AAS

PTB48540AAZ

PTB48540BAH

PTB48540BAZ

PTB48540CAD

PTB48540CAH

PTB48540CAS

PTB48540CAZ

NRND

Through-

EUP

EUQ

EUP

EUQ

EUP

EUQ

N / A for Pkg Type

Hole Module

Surface

SNPB

Level-1-235C-UNLIM/

Level-3-260C-168HRS

Mount Module

Surface

Pb-Free (RoHS)

TBD

SNAGCU Level-3-260C-168 HR

SN N / A for Pkg Type

SNAGCU Level-3-260C-168 HR

Mount Module

Through-

Hole Module

Surface

Mount Module

Through-

N / A for Pkg Type

Hole Module

Through-

Hole Module

Surface

SNPB

Level-1-235C-UNLIM/

Level-3-260C-168HRS

Mount Module

Surface

Pb-Free (RoHS)

SNAGCU Level-3-260C-168 HR

Mount Module

⁽¹⁾The marketing status values are defined as follows:

ACTIVE: Product device recommended for new designs.

LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect.

NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design.

PREVIEW: Device has been announced but is not in production. Samples may or may not be available.

OBSOLETE: TI has discontinued the production of the device.

⁽²⁾Eco Plan - The planned eco-friendly classification: Pb-Free (RoHS), Pb-Free (RoHS Exempt), or Green (RoHS & no Sb/Br) - please check http://www.ti.com/productcontent for the latest availability

information and additional product content details.

TBD: The Pb-Free/Green conversion plan has not been defined.

Pb-Free (RoHS): TI's terms "Lead-Free" or "Pb-Free" mean semiconductor products that are compatible with the current RoHS requirements for all 6 substances, including the requirement that

lead not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, TI Pb-Free products are suitable for use in specified lead-free processes.

Pb-Free (RoHS Exempt): This component has a RoHS exemption for either 1) lead-based flip-chip solder bumps used between the die and package, or 2) lead-based die adhesive used between

the die and leadframe. The component is otherwise considered Pb-Free (RoHS compatible) as defined above.

Green (RoHS & no Sb/Br): TI defines "Green" to mean Pb-Free (RoHS compatible), and free of Bromine (Br) and Antimony (Sb) based flame retardants (Br or Sb do not exceed 0.1% by weight

in homogeneous material)

Addendum-Page 1

PACKAGE OPTION ADDENDUM

www.ti.com

20-Jul-2012

⁽³⁾MSL, Peak Temp. -- The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder temperature.

Important Information and Disclaimer:The information provided on this page represents TI's knowledge and belief as of the date that it is provided. TI bases its knowledge and belief on information

provided by third parties, and makes no representation or warranty as to the accuracy of such information. Efforts are underway to better integrate information from third parties. TI has taken and

continues to take reasonable steps to provide representative and accurate information but may not have conducted destructive testing or chemical analysis on incoming materials and chemicals.

TI and TI suppliers consider certain information to be proprietary, and thus CAS numbers and other limited information may not be available for release.

In no event shall TI's liability arising out of such information exceed the total purchase price of the TI part(s) at issue in this document sold by TI to Customer on an annual basis.

Addendum-Page 2

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PTB48540CAS [TI]

相关型号：

PTB48540CAZ

PTB48560A

PTB48560AAH

PTB48560AAS

PTB48560AAZ

PTB48560B

PTB48560BAH

PTB48560BAS

PTB48560BAZ

PTB48560C

PTB48560CAH

PTB48560CAS