LTC4263 LINER [Linear Technology], LTC4263 Datasheet
LTC4263
Available stocks
Related parts for LTC4263
LTC4263 Summary of contents
Page 1
... LTC4263. When run from a single 48V supply, the LED pin can operate as a simple switching current source to reduce power dissipation in the LED drive circuitry. The LTC4263 is available in 14-pin 4mm × 3mm DFN and 14-pin SO packages. Single-Port Fully Autonomous PSE 0.1μF ...
Page 2
... UVLO_OFF V UVLO Hysteresis UVLO_HYS 2 (Notes 1, 2) Operating Ambient Temperature Range LTC4263C ................................................ 0°C to 70°C – 0. LTC4263I ............................................. –40°C to 85° Junction Temperature (Note 4) ............................. 125°C Storage Temperature Range ................... –65°C to 150°C – 0. Lead Temperature (Soldering, 10 sec – ...
Page 3
... Class 0 – 1 Class 1 – 2 Class 2 – 3 (Note 9) Class 0, Class 3, Class 4 Class 1 Class 2 2V ≤ (V – ≤ 3V OSC SS V – OSC SS V – OSC SS LTC4263 not driven externally. All voltages are DD5 MIN TYP 0 4.3 4 ...
Page 4
... Note 7: In order to reduce power dissipated in the switch while charging the PD, the LTC4263 reduces the current limit when V Refer to the Typical Performance Characteristics for more information. unless otherwise Note 8: The LTC4263 includes a high speed current limit circuit intended to SS protect against faults. The fault protection is activated for port current in excess of I ...
Page 5
... CURRENT IN V PORT SS 1Ω RESISTOR APPLIED TO OUTPUT OF CIRCUIT ON FRONT PAGE 1Ω SHORT I PORT 20A APPLIED 20A/ 0A DIV 4263 G14 1μs/DIV LTC4263 Classifi cation Transient Response to 40mA Load Step V – 48V DD48 25° OUT 2V/DIV V – 18V DD48 V – ...
Page 6
... LTC4263 TYPICAL PERFORMANCE CHARACTERISTICS Current Limit and Foldback 450 400 350 300 250 200 150 100 – V DD48 OUT 4263 G03 I DC Supply Current vs Supply DD48 Voltage with Internal V DD5 2 25°C A 25k LOAD WITH AC ENABLED 2 ...
Page 7
... V CLASS t t DETDLY DC Disconnect Timing I I OUT MIN V DD48 V OUT MPS PORT TURN-ON t PDC PON 4263 TT01 t MPDO 4263 TT03 LTC4263 Current Limit Timing I LIM I CUT I OUT t OVLD V DD48 V OUT V SS 4263 TT02 AC Disconnect Timing V OSC V DD48 V OUT ACDMIN ...
Page 8
... See the Applications Informa- tion section for a description of these patterns. When the LTC4263 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. This allows use of a simple inductor, ...
Page 9
... BLOCK DIAGRAM 14 V DD5 R LED + 1 LED 48V – TO OTHER LTC4263s 4 PWRMGT + 5V – 0.1μF 7 OSC BOLD LINES INDICATE HIGH CURRENT V DD48 11 5V REG INT5 EXT5 V DD5 4 500k CONTROL I DET HOT SWAP LTC4263 ENFCLS 13 0.1μF 2 LEGACY 3 MIDSPAN TO PORT ...
Page 10
... The LTC4263 controls a single PSE port that will detect, classify, and provide isolated 48V power device connected to the port. The LTC4263 senses removal with IEEE 802.3af compliant methods and turns off 48V power when the PD is disconnected. An internal control circuit takes care of system confi ...
Page 11
... This result is stored and the second current is applied to the port, allowed to settle and the voltage measured. The LTC4263 will not power the port if the PD has more than 5μF in parallel with its signature resistor unless legacy 30k mode is enabled ...
Page 12
... PD LOAD LINE CLASS – V DD48 OUT Figure 4. Classifi cation Load Lines Table 1. IEEE 802.3af Classifi cation, PD Power Consumption, and LTC4263 Enforced Power Output IEEE 802.3af CLASSIFICATION IEEE ALLOWABLE CLASS CURRENT 0 0mA to 5mA 1 8mA to 13mA 2 16mA to 21mA 3 ...
Page 13
... LTC4263 verifi es that the power supply is not over-allocated by verifying the node voltage remains below 1V. If the voltage is below 1V, the LTC4263 proceeds to power the port. If over 1V, the current is removed from the node, port powering is aborted, and the LTC4263 goes back into detection mode ...
Page 14
... MOSFET, sense resistor, or microcontroller to achieve IEEE compliance. The LTC4263 includes an internal MOSFET for driving the PSE port. The LTC4263 drives the gate of the internal MOSFET while monitoring the current and the output volt- age at the OUT pin. This circuitry couples the 48V input supply to the port in a controlled manner that satisfi ...
Page 15
... LTC4263. At port turn-on, while I is active, the instantaneous power dissipated by the LIM LTC4263 can be as high as 12W. This can cause 40ºC or more of die heating in a single turn-on sequence. Similarly, excessive heating can occur if an attached PD repeatedly pushes the LTC4263 into I ...
Page 16
... Figure 8. LTC4263 Using AC Disconnect detection, or wait 3.2 seconds before attempting detection again if in midspan mode. The LTC4263 may be reset by pulling the SD pin low. The port is turned off immediately and the LTC4263 sits idle. After SD is released there will be a 4-second delay before the next detection cycle begins ...
Page 17
... Power Sourcing Equipment. Because proper operation of the LTC4263 also depends on external components and power sources like the 48V supply, using the LTC4263 in a PSE does not in itself guarantee IEEE 802.3af compliance. To ensure a compliant PSE design recommended to adhere closely to the example ap- 4263 F09 plication circuits provided ...
Page 18
... The LTC4263 has a high speed fault current limit circuit that shuts down the port in 20μs (typ). In this case, there is lower inductance but higher current so the event is still severe ...
Page 19
... LTC4263. The V also requires a 0.1μF bypass capacitor. Fuse While the LTC4263 does not require a fuse for proper operation or for compliance with IEEE 802.3af, some safety requirements state that the output current must be limited to less than 2A in less than 60 seconds if any one component fails or is shorted ...
Page 20
... AC power distribution boundary. In this case, electrical isolation must be maintained between each port in the PSE. The LTC4263 can be used to build a multi-port Environment B PSE by powering each LTC4263 from a separate, isolated 48V supply. In all PSE applications, there should be no user accessible connections to the LTC4263 other than the RJ-45 port ...
Page 21
... V V DD5 DD48 LED 2 4 LEGACY PWRMGT 3 7 MIDSPAN OSC 13 8 ACOUT ENFCLS 5 10 OUT OUT SS LTC4263 MIDSPAN MIDSPAN IN OUT RJ45 RJ45 0.1μF SMAJ58A 100V MIDSPAN MIDSPAN IN OUT ...
Page 22
... LTC4263 PACKAGE DESCRIPTION 3.60 ±0.05 2.20 ±0.05 1.70 ± 0.05 RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS APPLY SOLDER MASK TO AREAS THAT ARE NOT SOLDERED PIN 1 TOP MARK (SEE NOTE 6) 0.200 REF NOTE: 1. DRAWING PROPOSED TO BE MADE VARIATION OF VERSION (WGED-3) IN JEDEC PACKAGE OUTLINE MO-229 2. DRAWING NOT TO SCALE 3 ...
Page 23
... N .053 – .069 (1.346 – 1.752) 0° – 8° TYP .014 – .019 (0.355 – 0.483) TYP LTC4263 .337 – .344 (8.560 – 8.738) NOTE .150 – .157 (3.810 – 3.988) NOTE 3 N/2 ...
Page 24
... LTC4263 TYPICAL APPLICATION Complete Single-Port Endpoint PSE with Integrated RJ45 ISOLATED 48V C3 0.1μF 100V U1 LTC4263 DD48 LED V DD5 4 12 PWRMGT 0.1μF OSC LEGACY C7, 0.47μ 100V, X7R MIDSPAN ACOUT ENFCLS OUT SS D5 CMLSHO5 ...