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LTC4263-1

42631fa

TYPICAL APPLICATION

FEATURES

APPLICATIONS

DESCRIPTION

High Power

Single PSE Controller

with Internal Switch

The LTC

4263-1 is a high power, single PSE controller for

use in Power over Ethernet systems. The internal current

limit and short-circuit protection are designed to provide

up to 30W of PSE output power for power hungry PoE

applications such as WAPs, security cameras and RFID

readers.

The LTC4263-1 includes IEEE 802.3af compliant PD detec-

tion circuitry along with selectable AC and DC disconnect

sensing, allowing seamless operation in conventional

IEEE 802.3af systems as well as propriety, high power

applications. The LTC4263-1 simpliﬁ es PSE implementa-

tion, needing only a single supply and a small number of

passive support components. Onboard control algorithms

provide complete PSE functionality without the need of a

microcontroller and built-in foldback and thermal shutdown

provide comprehensive fault protection. An LED pin indi-

cates the state of the port and detection backoff timing is

conﬁ gurable for either endpoint or midspan operation.

The LTC4263-1 is available in a miniature 14-pin 4mm ×

3mm DFN package.

30W PSE Output Power

IEEE 802

.3af Compatible

Operation from a Single 56V Supply

Fully Autonomous Operation Without a

Microcontroller

Internal MOSFET with Thermal Protection

Precision Inrush Control with Internal Sense Resistor

Forced Current PD Detection for Noise Immunity

AC and DC Disconnect Sensing

Legacy PD Detection

Robust Short-Circuit Protection

Pin-Selectable Detection Backoff for Midspan PSEs

LED Driver Indicates Port On and Blinks

Status Codes

Available in a Miniature14-Pin 4mm × 3mm DFN

Package

High Power Endpoint/Midspan PSEs

Single-Port or Multi-Port Power Injectors

Low Port Count PSEs

Environment B PSEs

Standalone PSEs

Single-Port Fully Autonomous High Power PSE

42631 TA01

0.1μF

100V

0.1μF

100V

SMAJ58A

LED

LEGACY

MIDSPAN

OSC

LTC4263-1

ISOLATED

56V SUPPLY

–

TO PORT

MAGNETICS

DD5

DD48

OUT

ACOUT

L, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.

All other trademarks are the property of their respective owners.

Summary of content (20 pages)

PAGE 1
LTC4263-1 High Power Single PSE Controller with Internal Switch FEATURES DESCRIPTION n The LTC®4263-1 is a high power, single PSE controller for use in Power over Ethernet systems. The internal current limit and short-circuit protection are designed to provide up to 30W of PSE output power for power hungry PoE applications such as WAPs, security cameras and RFID readers. n n n n n n n n n n n n 30W PSE Output Power IEEE 802®.
PAGE 2
LTC4263-1 ABSOLUTE MAXIMUM RATINGS PIN CONFIGURATION (Note 1, Note 2) Supply Voltages VSS – VDD48 ........................................... 0.3V to –80V VDD5........................................VSS – 0.3V to VSS + 6V Pin Voltages and Currents LEGACY, MIDSPAN, SD, OSC ..VSS – 0.3V to VSS +6V LED .......................................VSS – 0.3V to VSS + 80V OUT, ACOUT ............................................ (See Note 3) Operating Ambient Temperature Range LTC4263CDE-1 ...........................
PAGE 3
LTC4263-1 ELECTRICAL CHARACTERISTICS The l denotes the speciﬁcations which apply over the full operating temperature range, otherwise speciﬁcations are at TA = 25°C. VDD48 – VSS = 48V and VDD5 not driven externally. All voltages are relative to VSS unless otherwise noted.
PAGE 4
LTC4263-1 ELECTRICAL CHARACTERISTICS The l denotes the speciﬁcations which apply over the full operating temperature range, otherwise speciﬁcations are at TA = 25°C. VDD48 – VSS = 48V and VDD5 not driven externally. All voltages are relative to VSS unless otherwise noted.
PAGE 5
LTC4263-1 TYPICAL PERFORMANCE CHARACTERISTICS Powering a Legacy PD with 470μF Bypass Capacitor Powering an IEEE 802.
PAGE 6
LTC4263-1 TYPICAL PERFORMANCE CHARACTERISTICS 675 4 450 375 300 225 150 TA = 25°C 25k LOAD WITH AC ENABLED 2.0 3 IDD48 (mA) VLED PIN PULL-DOWN (V) 525 2.5 TA = 25°C INTERNAL VDD5 600 IOUT (mA) IDD48 DC Supply Current vs Supply Voltage with Internal VDD5 LED Pin Pull-Down vs Load Current Current Limit and Foldback 2 1 1.5 NO LOAD 1.0 0.5 75 0 0 0 5 10 15 20 25 30 35 40 45 50 VDD48 – VOUT (V) 0 10 20 30 40 ILED LOAD CURRENT (mA) 0 50 42631 G03 25k LOAD WITH AC ENABLED 1.
PAGE 7
LTC4263-1 TEST TIMING Detect and Turn-On Timing Current Limit Timing PD INSERTED ILIM IOUT VDD48 ICUT tOVLD VDD48 VOUT tDET VSS VOUT 42631 TT02 PORT TURN-ON tDETDLY tPON 42631 TT01 DC Disconnect Timing IOUT AC Disconnect Timing IMIN VOSC VDD48 VDD48 VOUT VSS VOUT tMPS tMPDO VSS 42631 TT03 IACOUT IACDMIN PD REMOVED tMPDO 42631 TT04 42631fa 7
PAGE 8
LTC4263-1 PIN FUNCTIONS LED (Pin 1): Port State LED Drive. This pin is an opendrain output that pulls down when the port is powered. Under port fault conditions, the LED will ﬂash in patterns to indicate the nature of the port fault. See the Applications Information section for a description of these patterns. When the LTC4263-1 is operated from a single 48V supply, this pin is pulsed low with a 6% duty cycle during the periods when the LED should be on.
PAGE 9
LTC4263-1 BLOCK DIAGRAM 1A 11 14 VDD5 VDD5 RLED INT5 EXT5 VDD48 12 SD 5V REG 0.1μF 2 LEGACY 3 MIDSPAN + 1 56V 3 LED – TO PORT MAGNETICS 500k CONTROL + SMAJ58A 5V – Hot SwapTM 13 4 5 6 IDET 500k 9 VSS 10 OUT 0.47μF 0.
PAGE 10
LTC4263-1 APPLICATIONS INFORMATION POE OVERVIEW A PSE is required to provide 44V to 57V DC between either the signal pairs or the spare pairs as shown in Figure 1. The power is applied as a voltage between two of the pairs, typically by powering the center taps of the isolation transformers used to couple the differential data signals to the wire.
PAGE 11
LTC4263-1 accidentally powered. Disconnect with either AC or DC methods using the LTC4263-1 is fully compliant and insures safe power removal after PD disconnect. Command and control for the LTC4263-1 is handled internally without the need of a microcontroller, thereby simplifying system design. LTC4263-1 OPERATION The IEEE 802.3af speciﬁcation deﬁnes a speciﬁc pair-topair signature resistance used to identify a device that can accept power via its Ethernet connection.
PAGE 12
LTC4263-1 APPLICATIONS INFORMATION Power Control The primary function of the LTC4263-1 is to control the delivery of power to the PSE port. In order to provide a robust solution, a variety of current limit and current monitoring functions are needed, as shown in Figure 4. All control circuitry is integrated and the LTC4263-1 requires no external MOSFET, sense resistor, or microcontroller. The LTC4263-1 includes an internal MOSFET for driving the PSE port.
PAGE 13
LTC4263-1 APPLICATIONS INFORMATION If the undercurrent condition goes away before tMPDO (350ms (typ)), the timer is reset to zero. The DC disconnect circuit includes a glitch ﬁlter to prevent noise from falsely resetting the timer. The current must be present for a period of at least 20ms to guarantee reset of the timer. To enable DC disconnect, tie the OSC pin to VSS . 750 ILIM (mA) 600 450 300 AC Disconnect 150 0 5 0 10 15 20 25 30 35 40 45 50 VDD48 – VOUT (V) 42631 F07 Figure 5.
PAGE 14
LTC4263-1 APPLICATIONS INFORMATION 1A + 0.1μF 100V ISOLATED 56V SUPPLY CPSE 0.1μF X7R, 100V LTC4263-1 NC 0.1μF LED LEGACY MIDSPAN – 0.1μF X7R VDD5 SMAJ58A VSS 500k SD VSS VDD48 VSS OUT VSS OUT CMLSH05-4 42631 F06 DAC RDET 1k OSC CDET 0.47μF X7R, 100V ACOUT Figure 6. LTC4263-1 Using AC Disconnect compact and functionally robust system. Moreover, the complete Power over Ethernet AC disconnect system (PSE, transformers, cabling, PD, etc.
PAGE 15
LTC4263-1 APPLICATIONS INFORMATION Table 1.
PAGE 16
LTC4263-1 APPLICATIONS INFORMATION POUT(MIN) = 28.8W (MIN, DC DISCONNECT) = 28.5W (MIN, AC DISCONNECT) POWER (MIN) = 55V (MIN) • 540mA (MIN) = 29.7W (MIN) LTC4263-1 POWER SUPPLY VSUPPLY 55V TO 57V ICUT(MIN) = 540mA RON(MAX) = 3Ω CABLE LOSS (MAX) = (540mA)2 • 12.5Ω = 3.6W AC DISCONNECT DIODE (OPTIONAL) PD 100M CAT5 CABLE 12.5Ω (MAX) PLOSS_AC DIODE(MAX) = 0.5V • 540mA = 0.3W (MAX) PLOSS_4263-1(MAX) = (540mA)2 • 3Ω = 0.9W (MAX) 42631 F08 POUT(MIN) = 25.2W (MIN, DC DISCONNECT) = 24.
PAGE 17
LTC4263-1 APPLICATIONS INFORMATION PSE PD + 0.1μF 0.1μF VDD48 56V 1 1 2 2 Rx Tx DATA PAIR 0.1μF SMAJ58A GND RCLASS PWRGD LTC4263-1 3 VDD5 3 6 DATA PAIR VIN 6 VOUT SMAJ58A 58V – VSS OUT 0.1μF VDD48 4 4 Tx Rx 5 56V DATA PAIR 5 – – DC/DC CONVERTER VOUT 7 Rx Tx 8 0.1μF + 5μF MIN GND RCLASS PWRGD VIN 7 + + LTC4264 LTC4263-1 VDD5 – SMAJ58A 0.1μF 0.1μF – VOUT 8s B2100 + DC/DC CONVERTER LTC4264 Tx Rx 0.
PAGE 18
LTC4263-1 APPLICATIONS INFORMATION If the port voltage reverses polarity and goes positive, the OUT pin can be overstressed because this voltage is stacked on top of the 56V supply. In this case, the transient suppresser is used to clamp the voltage to a small positive value to protect the LTC4263-1 and the PSE capacitor. For this reason, it is critical that only a unidirectional TVS be used.
PAGE 19
LTC4263-1 PACKAGE DESCRIPTION DE Package 14-Lead Plastic DFN (4mm × 3mm) (Reference LTC DWG # 05-08-1708 Rev B) 0.70 ±0.05 3.30 ±0.05 3.60 ±0.05 2.20 ±0.05 1.70 ± 0.05 PACKAGE OUTLINE 0.25 ± 0.05 0.50 BSC 3.00 REF RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS APPLY SOLDER MASK TO AREAS THAT ARE NOT SOLDERED R = 0.115 TYP 4.00 ±0.10 (2 SIDES) R = 0.05 TYP 3.00 ±0.10 (2 SIDES) 0.40 ± 0.10 8 14 3.30 ±0.10 1.70 ± 0.10 PIN 1 NOTCH R = 0.20 OR 0.
PAGE 20
LTC4263-1 TYPICAL APPLICATION Complete High Power Single Port Endpoint PSE L2 6 + ISOLATED 56V – L1: COILCRAFT DS1608C-106 L2: COILCRAFT ETH1-230LD • • 9 • • 1 2 10 11 PHY L1 10mH R2 1k • 5 D1 BAS19 LTC4263-1 11 14 VDD48 VDD5 1 12 LED SD 7 2 OSC LEGACY 3 MIDSPAN 13 VSS 4 8 VSS ACOUT 5 10 VSS OUT 6 9 VSS OUT C1 0.1μF LED1 LN1351C-TR GRN C3 0.1μF 100V • C5 0.1μF X7R C7 0.47μF R6 100V, X7R 1k D5 CMLSHO5-4 4 3 OUT TO CABLE 12 2 1 • • • • 13 • • 3 6 14 F1 1A D2 SMAJ58A C4 0.