Texas Instruments TPS 2375 – 1, TPS 2377 – 1 INSTALLATION INSTRUCTIONS

D−8 PW−8

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V

DD

Input

Current

V

RTN

V

Detect Classify

Power Up

and

Inrush

Class 3

(PG-RTN)

Note: All Voltages With Respect to VSS.

Current

RX

Pair

TPS2375-1

SMAJ58A

0.1 F, 100 V, 10%m

24.9 kW

1%

VDD

VSS

CLASS

DET

RTN

PG

100 kW

(2)

1

3

6

4

5

7

8

TO DC/DC

CONVERTER

ILIM

178 kW

1%

2

RJ-45

DF01S

2 Places

Data to

Ethernet PHY

Data to

Ethernet PHY

R

DET

R

CLASS

357

1%

W

(1)

R

ILIM

47 F,m

100 V

Notes:

1) Class 3 PD depicted

2) PG pullup resistor is optional.

TX

Pair

Spare

Pair

Spare

Pair

TPS2375-1
TPS2377-1

SLVS570 – MARCH 2005

IEEE 802.3af PoE POWERED DEVICE CONTROLLERS WITH AUTO-RETRY

FEATURES APPLICATIONS

• Auto-Retry After Current-Limit Fault

• TPS2375-1: IEEE 802.3af Thresholds

• TPS2377-1: Legacy Thresholds

• Fully Supports IEEE 802.3af Specification

• Integrated 0.58- Ω , 100-V, Low-Side Switch

• 15-kV System Level ESD Capable

• Programmable Inrush Current Control

• Fixed 450-mA Current Limit

• Open-Drain, Power-Good Reporting

• Industrial Temperature Range: -40 ° C to 85 ° C

• 8-Pin SOIC and TSSOP Packages

DESCRIPTION

These easy-to-use 8-pin integrated circuits contain all of the features needed to develop an IEEE

802.3af-compliant powered device (PD). The TPS2375-1 and TPS2377-1 are second generation PDCs (PD
Controllers) featuring a 100-V ratings and true open-drain, power-good function. These devices are auto-retry
versions of selected TPS2375 family members. Information on the TPS2375/6/7 devices can be found on the
TPS2375/6/7 data sheet (SLVS525A ).

In addition to the basic functions of detection, classification, and undervoltage lockout (UVLO), these controllers
include an adjustable inrush limiting feature. The TPS2375-1 has 802.3af-compliant UVLO limits, and the
TPS2377-1 has legacy UVLO limits.

The TPS2375 family specifications incorporate a voltage offset of 1.5 V between its limits and the IEEE 802.3af
specifications to accommodate the required input diode bridges used to make the PD polarity insensitive.

• VoIP Phones

• WLAN Access Points

• Security Cameras

• Internet Appliances

• POS Terminals

PRODUCT SELECTOR

2375-1 2377-1 2375 2376 2377

UVLO 802.3af Legacy 802.3af Adjustable Legacy

Protection Auto-Retry Auto-Retry Latch Latch Latch

Package PW D D, PW D,PW D,PW

Additional resources can be found on the TI Web site www.ti.com.

Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.

PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.

Figure 1. Typical Application Circuit and Start-Up Waveforms

Copyright © 2005, Texas Instruments Incorporated

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TPS2375-1
TPS2377-1

SLVS570 – MARCH 2005

This integrated circuit can be damaged by ESD. Texas Instruments recommends that all integrated
circuits be handled with appropriate precautions. Failure to observe proper handling and installation
procedures can cause damage.

ESD damage can range from subtle performance degradation to complete device failure. Precision
integrated circuits may be more susceptible to damage because very small parametric changes could
cause the device not to meet its published specifications.

AVAILABLE OPTIONS

T

A

-40 ° C to 85 ° C

(1) Add an R suffix to the device type for tape and reel.

UVLO THRESHOLDS (NOMINAL) PACKAGE

TYPE LOW HIGH SO-8 TSSOP-8

802.3af 30.5 V 39.3 V -- TPS2375PW-1 2375-1
Legacy 30.5 V 35.1 V TPS2377D-1 -- 2377-1

ABSOLUTE MAXIMUM RATINGS

over operating free-air temperature range (unless otherwise noted)

VDD, RTN, DET, PG

Voltage ILIM, UVLO -0.3 V to 10 V

CLASS -0.3 V to 12 V

(3)

RTN

Current, sinking PG 0 to 5 mA

DET 0 to 1 mA

Current, sourcing

ESD Charged device model 500 V

T

J

T

stg

(1) Stresses beyond those listed under “absolute maximum ratings” may cause permanent damage to the device. These are stress ratings

only, and functional operation of the device at these or any other conditions beyond those indicated under “recommended operating

conditions” is not implied. Exposure to absolute–maximum–rated conditions for extended periods may affect device reliability.
(2) I
(3) SOA limited to V
(4) Surges applied to RJ-45 of Figure 1 between pins of RJ-45, and between pins and output voltage rails per EN61000-4-2, 1999.

= 0

(RTN)

Maximum junction temperature range Internally limited
Storage temperature range -65 ° C to 150 ° C
Lead temperature 1,6 mm (1/16 inch) from case for 10 seconds - Green Packages 260 ° C
Lead temperature 1,6 mm (1/16 inch) from case for 10 seconds - Nongreen 235 ° C

Packages

(RTN)

= 80 V and I

= 515 mA.

(RTN)

CLASS 0 to 50 mA
ILIM 0 to 1 mA
Human body model 2 kV

System level (contact/air) at RJ-45

(1)

, voltages are referenced to V

(2)

(4)

(1)

(VSS)

TPS237x

-0.3 V to 100 V

0 to 515 mA

8/15 kV

MARKING

DISSIPATION RATING TABLE

PACKAGE

D (SO-8) 238 150 266

PW (TSSOP-8) 258.5 159 251

(1) Tested per JEDEC JESD51. High-K is a (2 signal – 2 plane) test board and low-K is a double-sided

board with minimum pad area and natural convection.

(2) For the most current package and ordering information, see the Package Option Addendum at the

end of this document, or see the TI Web site at www.ti.com .

2

(2)

θJA(LOW-K) θJA(HIGH-K)

° C/W ° C/W

(1)

POWER RATING

TA= 85 ° C (HIGH-K)

(mW)

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TPS2375-1
TPS2377-1

SLVS570 – MARCH 2005

RECOMMENDED OPERATING CONDITIONS

MIN MAX UNIT

Input voltage range

Operating current range (sinking) RTN 0 350 mA

(1)

(1)

R

(ILIM)

Classification resistor
Inrush limit program resistor
Sinking current PG 0 2 mA

T

Operating junction temperature -40 125 ° C

J

T

Operating free–air temperature -40 85 ° C

A

(1) Voltage should not be externally applied to CLASS and ILIM.

ELECTRICAL CHARACTERISTICS

V

= 48 V, R

(VDD)

currents are into pins. Typical values are at 25 ° C. All voltages are with respect to VSS unless otherwise noted.

DETECTION

CLASSIFICATION

I

(CLASS)

V

(CL_ON)

V

(CU_OFF)

V

(CU_H)

PASS DEVICE

r

DS(on)

I

(LIM)

(1) Classification is tested with exact resistor values. A 1% tolerance classification resistor ensures compliance with IEEE 802.3af limits.
(2) This parameter specifies the RTN current value, as a percentage of the steady state inrush current, below which it must fall to make PG

assert (open-drain).

= 24.9 k Ω , R

(DET)

(CLASS)

PARAMETER TEST CONDITIONS MIN TYP MAX UNIT

Offset current 0.3 3 µA

Sleep current 4 12 µA
DET leakage current V

Detection current

Classification current

(1)

Classification lower threshold Regulator turns on, V

Classification upper threshold

Leakage current V

On resistance I
Leakage current V
Current limit V
Inrush limit V

Inrush current termination

(2)

Current rise time into inrush I

Current limit response time µs
Leakage current, ILIM V

VDD, PG, RTN 0 57 V
UVLO 0 5 V

CLASS 255 4420 Ω

62.5 500 k Ω

= 255 Ω , R

DET open, V
I

(VDD)

DET open, V
I

(VDD)

(DET)

V

(RTN)

R

(DET)

measure I
I

(DET)

R

(CLASS)

R

(CLASS)

R

(CLASS)

R

(CLASS)

R

(CLASS)

Regulator turns off, V
Hysteresis 0.5 0.78 1 V

(CLASS)

(RTN)

(VDD)
(RTN)
(RTN)

V

(RTN)

state → normal operation
R

(ILIM)

(RTN)

past upper UVLO
Apply load ∞ Ω → 20 Ω , time measured to 2 2.5

I

(RTN)

(VDD)

= 178 k Ω , and –40 ° C ≤ TJ≤ 125 ° C, unless otherwise noted. Positive

(ILIM)

= V

(VDD)

+ I

(RTN)

(VDD)

+ I

(RTN)

= V

(VDD)

= V

, V

(VDD)

= 24.9 k Ω ,

(VDD)

= 4420 Ω , 13 ≤ V
= 953 Ω , 13 ≤ V
= 549 Ω , 13 ≤ V
= 357 Ω , 13 ≤ V
= 255 Ω , 13 ≤ V

= 0 V, V

= 57 V, measure I

+ I

(VDD)

= 1.9 V, measure

(RTN)

= V

= 10.1 V, measure

(RTN)

(DET)

= 1.4 V 53.7 56 58.3 µA

(VDD)

+

(RTN)

V

= 10.1 V 395 410 417 µA

(VDD)

≤ 21 V 2.2 2.4 2.8

(VDD)

≤ 21 V 10.3 10.6 11.3

(VDD)

≤ 21 V 17.7 18.3 19.5 mA

(VDD)

≤ 21 V 27.1 28 29.5

(VDD)

≤ 21 V 38 39.4 41.2

(VDD)

rising 10.2 11.3 13.0 V

(VDD)

rising 21 21.9 23 V

(VDD)

0.1 5 µA

= 57 V 1 µA

= 300 mA 0.58 1.0 Ω

= V

= 30 V 15 µA

(RTN)

= 1 V 405 461 515 mA
= 2 V, R
falling, R

= 69.8 k Ω , V

= 30 mA → 300 mA, V

= 178 k Ω 100 130 180 mA

(ILIM)

= 178 k Ω , inrush 85% 91% 100%

(ILIM)

= 5 V, 15 25

(RTN-VSS)

increasing µs

(VDD)

= 45 mA

= 15 V, V

= 0 V 1 µA

(UVLO)

3

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TPS2375-1
TPS2377-1

SLVS570 – MARCH 2005

ELECTRICAL CHARACTERISTICS (continued)

V

= 48 V, R

(VDD)

currents are into pins. Typical values are at 25 ° C. All voltages are with respect to VSS unless otherwise noted.

PG

UVLO

V

(UVLO_R)

V

(UVLO_F)

THERMAL SHUTDOWN

BIAS CURRENT

(DET)

= 24.9 k Ω , R

= 255 Ω , R

(CLASS)

= 178 k Ω , and –40 ° C ≤ TJ≤ 125 ° C, unless otherwise noted. Positive

(ILIM)

PARAMETER TEST CONDITIONS MIN TYP MAX UNIT

Voltage threshold rising

(3)

V

rising 9.5 10 10.5 V

(RTN)

PG deglitch Delay rising and falling PG 75 150 225 µs

I

Output low voltage

Leakage current V

TPS2375 Voltage at VDD V

= 2 mA, V

(PG)

V

= 38 V, V

(VDD)

I

= 2 mA, V

(PG)

= 57 V, V

(PG)

V

rising 38.4 39.3 40.4

(VDD)

falling 29.6 30.5 31.5 V

(VDD)

= 34 V, 0.12 0.4

(RTN)

falling

(RTN)

= 0 V, V

(RTN)

= 0 V 0.1 1 µA

(RTN)

= 25 V 0.12 0.4 V

(VDD)

Hysteresis 8.3 8.8 9.1
V

rising 34.1 35.1 36.0

(VDD)

TPS2377 Voltage at VDD V

falling 29.7 30.5 31.4 V

(VDD)

Hysteresis 4.3 4.5 4.8

Shutdown temperature Temperature rising 135 ° C
Hysteresis 20 ° C

Operating current I

(VDD)

V

240 450 µA

(3) Start with V

= 0 V, then increase V

(RTN)

until PG switches. Measure before thermal shutdown occurs.

(RTN)

4

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DEVICE INFORMATION

-

+

10-V

Regulator

Thermal Shutdown

QS

R

-

+

-

+

3

2

12 V

22 V

1.5 V

& 10 V

2.5 V

-

+

VDD

RTN

45 mV

CLASS

DET

Current

Limit Amp.

UVLO

Comp.

EN

Delay

5

8

6

PG

-

+

1 = Inrush

1 = Limiting

PG Comparator

Detection

Comparator

Classification

Comparator

0

1

-

+

2.5 V

1

ILIM

1:1

4

VSS

Current

Mirror

1 kW

0.08 W

150 Sm

FUNCTIONAL BLOCK DIAGRAM

TPS2375-1
TPS2377-1

SLVS570 – MARCH 2005

5

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1

2

3

4

5

6

7

8

VSS

CLASS

N/C

DET

RTN

PG

VDD

ILIM

I

(LIM)



25000

R

(ILIM)

TPS2375-1
TPS2377-1

SLVS570 – MARCH 2005

DEVICE INFORMATION (continued)

TPS2375-1/77-1

(TOP VIEW)

TERMINAL FUNCTIONS

PIN NAME PIN NUMBER I/O DESCRIPTION

ILIM 1 O equation for calculating the resistor is shown in the detailed pin description section for

CLASS 2 O (PD). The IEEE classification levels and corresponding resistor values are shown in

DET 3 O Connect a 24.9-k Ω detection resistor from DET to VDD for a valid PD detection.
VSS 4 I Return line on the source side of the TPS2375-1 from the PSE.

RTN 5 O
PG 6 O Open-drain, power-good output; active high.

NC 7 No connection
VDD 8 I Positive line from the rectified PSE provided input.

Connect a resistor from ILIM to VSS to set the start-up inrush current limit. The
ILIM.

Connect a resistor from CLASS to VSS to set the classification of the powered device
Table 1 .

Switched output side return line used as the low-side reference for the TPS2375-1
load.

Detailed Pin Description

The following descriptions refer to the schematic of Figure 1 and the functional block diagram.
ILIM: A resistor from this pin to VSS sets the inrush current limit per Equation 1 :

where ILIM is the desired inrush current value, in amperes, and R
from ILIM to VSS, in ohms. The practical limits on R

are 62.5 k Ω to 500 k Ω . A value of 178 k Ω is

(ILIM)

recommended for compatibility with legacy power sourcing equipment (PSE).
Inrush current limiting prevents current drawn by the bulk capacitor from causing the line voltage to sag below

the lower UVLO threshold. Adjustable inrush current limiting allows the use of arbitrarily large capacitors and also
accommodates legacy systems that require low inrush currents.

The ILIM pin must not be left open or shorted to VSS.
CLASS: Classification is implemented by means of an external resistor, R

and VSS. The controller draws current from the input line through R
13 V and 21 V. The classification currents specified in the electrical characteristics table include the bias current
flowing into VDD and any RTN leakage current.

Table 1. CLASSIFICATION

CLASS PD POWER (W) R

0 0.44 – 12.95 4420 ± 1% 0 - 4 Default class
1 0.44 – 3.84 953 ± 1% 9 - 12
2 3.84 – 6.49 549 ± 1% 17 - 20
3 6.49 – 12.95 357 ± 1% 26 - 30
4 - 255 ± 1% 36 - 44 Reserved for future use

( Ω ) 802.3af LIMITS (mA) NOTE

(CLASS)

is the value of the programming resistor

(ILIM)

, connected between CLASS

(CLASS)

(CLASS)

when the input voltage lies between

(1)

6

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TPS2375-1
TPS2377-1

SLVS570 – MARCH 2005

The CLASS pin must not be shorted to ground.
DET: Connect a resistor, R

applications. R

is connected across the input line when V

(DET)

disconnected when the line voltage exceeds this range to conserve power. This voltage range has been chosen
to allow detection with two silicon rectifiers between the controller and the RJ-45 connector.

VSS: This is the input supply negative rail that serves as a local ground.
RTN: This pin provides the switched negative power rail used by the downstream circuits. The operational and

inrush current limit control current into the pin. The PG circuit monitors the RTN voltage and also uses it as the
return for the PG pin pulldown transistor. The internal MOSFET body diode clamps VSS to RTN when voltage is
present between VDD and RTN and the Power-over-Ethernet (PoE) input is not present.

PG: This pin goes to a high resistance state when the internal MOSFET that feeds the RTN pin is enabled, and
the device is not in inrush current limiting. In all other states except detection, the PG output is pulled to RTN by
the internal open-drain transistor. Performance is ensured with at least 4 V between VDD and RTN.

PG is an open-drain output; therefore, it may require a pullup resistor or other interface.
VDD: This is the positive input supply that is also common to downstream load circuits. This pin provides

operating power and allows the controller to monitor the line voltage to determine the mode of operation.

, between DET and VDD. This resistor should equal 24.9 k Ω , ± 1% for most

(DET)

lies between 1.4 V and 11.3 V, and is

(VDD)

7