LTC4267CDHC#PBF Linear Technology, LTC4267CDHC#PBF Datasheet
LTC4267CDHC#PBF
Specifications of LTC4267CDHC#PBF
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LTC4267CDHC#PBF Summary of contents
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... APPLICATIO S IP Phone Power Management ■ Wireless Access Points ■ Security Cameras ■ Power over Ethernet ■ , LT, LTC and LTM are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. U TYPICAL APPLICATIO + –48V HD01 FROM DATA PAIR – ...
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LTC4267 ABSOLUTE AXI U RATI GS (Note 1) V with Respect to V Voltage ... 0.3V to –100V PORTN PORTP , SIGDISA, ⎯ P ⎯ W ⎯ R ⎯ G ⎯ OUT Voltage ..................... V ...
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ELECTRICAL CHARACTERISTICS temperature range, otherwise specifi cations are at T SYMBOL PARAMETER V V – V Margin MARGIN CLAMP1mA TURNON I V Supply Current when ON VPORTN_ON PORTN I P Supply Current PVCC_ON VCC Normal Operation Start- Supply ...
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LTC4267 ELECTRICAL CHARACTERISTICS temperature range, otherwise specifi cations are at T SYMBOL PARAMETER t NGATE Drive Rise Time RISE t NGATE Drive Fall Time FALL V Peak Current Sense Voltage IMAX I Peak Slope Compensation Output Current SLMAX t Soft-Start ...
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W U TYPICAL PERFOR A Input Current vs Input Voltage 25k Detection Range 0 25°C A 0.4 0.3 0.2 0 –2 –4 –6 –8 V VOLTAGE (V) PORTN 4267 G01 Input Current vs Input Voltage 3 ...
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LTC4267 W U TYPICAL PERFOR A CE CHARACTERISTICS Reference Voltage vs Temperature 812 VCC 808 804 800 796 792 788 –50 –30 – TEMPERATURE (°C) 4267 G10 Oscillator Frequency vs Supply Voltage ...
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W U TYPICAL PERFOR A CE CHARACTERISTICS Start-Up I Supply Current vs PVCC Temperature – 0.1V VCC TURNON –50 –30 – TEMPERATURE (°C) 4267 G19 ...
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LTC4267 CTIO S (GN/DHC) I /RUN (Pin 2/Pin 1): Current Threshold/Run Input. This TH pin performs two functions. It serves as the switching regulator error amplifi er compensation point as well as the run/shutdown control ...
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BLOCK DIAGRAM V PORTP CLASSIFICATION CURRENT LOAD + 1.237V – 25k EN SIGNATURE R CLASS RESISTOR POWER GOOD CONTROL CIRCUITS INPUT CURRENT 375mA LIMIT EN + 140mA – V PORTN BOLD LINE INDICATES HIGH CURRENT PATH U U APPLICATIO S ...
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LTC4267 U U APPLICATIO S I FOR ATIO specifi avoid corrupting the 25kΩ signature resistor while also saving board space and cost. In addition, the in- rush current limit requirement of the IEEE 802.3af standard can cause large ...
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U U APPLICATIO S I FOR ATIO Series Diodes The IEEE 802.3af-defi ned operating modes for a PD refer- ence the input voltage at the RJ45 connector on the PD. The PD must be able to accept power of either ...
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LTC4267 U U APPLICATIO S I FOR ATIO LTC4267 SIGNATURE DISABLE 9k TO 25k SIGNATURE PSE RESISTOR 16k V PORTN Figure 3. 25k Signature Resistor with Disable Classifi cation Once the PSE has detected a PD, the PSE may option- ...
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U U APPLICATIO S I FOR ATIO the classifi cation current is reenabled. C1 will discharge through the PD circuitry and the P OUT impedance state. LTC4267 V PORTP TO PSE UNDERVOLTAGE LOCKOUT CIRCUIT PGND V P PORTN INPUT LTC4267 ...
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LTC4267 U U APPLICATIO S I FOR ATIO LTC4267 THERMAL SHUTDOWN UVLO – TO PSE + + 1.125V – 300k V PORTN Figure 6. LTC4267 Power Good the LTC4267 will attempt to quickly charge capacitor C1 using an internal secondary ...
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U U APPLICATIO S I FOR ATIO temperature exceeds the overtemperature trip point, the current is reduced to zero and very little power is dissi- pated in the part until it cools below the overtemperature set point. Once the LTC4267 ...
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LTC4267 U U APPLICATIO S I FOR ATIO The undervoltage lockout mechanism on P the LTC4267 switching regulator from trying to drive the external N-Channel MOSFET with insuffi cient gate-to- LTC4267 PWM SHUTDOWN V /RUN ITH < < ...
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U U APPLICATIO S I FOR ATIO Diode Bridge IEEE 802.3af allows power wiring in either of two confi gu- rations: on the TX/RX wires or via the spare wire pairs in the RJ45 connector. The PD is required to ...
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LTC4267 U U APPLICATIO S I FOR ATIO RJ45 + – – PULSE H2019 + SPARE – SPARE 8 Figure 9. PD Front ...
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U U APPLICATIO S I FOR ATIO Signature Disable Interface To disable the 25kΩ signature resistor, connect SIGDISA pin to the V pin. Alternately, SIGDISA pin can be driven PORTP high with respect example of a ...
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LTC4267 U U APPLICATIO S I FOR ATIO Choose resistance values for R1 and large as possible to minimize any effi ciency loss due to the static current drawn from V , but just small enough ...
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U U APPLICATIO S I FOR ATIO + –48V FROM DATA PAIR – + –48V FROM SPARE PAIR – + –48V FROM DATA PAIR – + –48V FROM SPARE PAIR – ISOLATED DESIGN EXAMPLE V PORTP C1 R ...
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LTC4267 U U APPLICATIO S I FOR ATIO Programmable Slope Compensation The LTC4267 switching regulator injects a ramping current through its SENSE pin into an external slope compensation resistor (R in Figure 11). This current ramp starts at SL zero ...
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U U APPLICATIO S I FOR ATIO The shunt regulator can sink up to 5mA through the P pin to PGND. The values of R START selected for the application to withstand the worst-case load conditions and drop on P ...
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LTC4267 U U APPLICATIO S I FOR ATIO LTC4267 I /RUN PGND Figure 15. Main Loop Compensation for a Nonisolated Design Selecting the Switching Transistor With the N-channel power MOSFET driving the primary of the ...
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U U APPLICATIO S I FOR ATIO OPTION 1: AUXILIARY POWER INSERTED BEFORE LTC4267 PD RJ45 + – – SPARE – SPARE 8 ISOLATED WALL TRANSFORMER ...
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LTC4267 U U APPLICATIO S I FOR ATIO transformer voltage is higher than the PSE voltage, the LTC4267 switching regulator will draw power from the transformer. In this situation necessary to address the issue of power cycling that ...
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U U APPLICATIO S I FOR ATIO with minimum trace lengths and minimum capacitance nonisolated application, R1, and R2 should be placed as close as possible to the V pin of the LTC4267 and FB C should be ...
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LTC4267 U TYPICAL APPLICATIO S + –48V HD01 FROM DATA PAIR – + –48V HD01 FROM SPARE PAIR – *1µF CERAMIC + 4.7µF TANTALUM ** THREE 100µF CERAMICS 28 Class 3 PD with 5V Nonisolated Power Supply 5µF* MIN 100k ...
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U TYPICAL APPLICATIO S LTC4267 4267fc 29 ...
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LTC4267 PACKAGE DESCRIPTIO RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS NOTE: 1. DRAWING PROPOSED TO BE MADE VARIATION OF VERSION (WJED-1) IN JEDEC PACKAGE OUTLINE MO-229 2. DRAWING NOT TO SCALE 3. ALL DIMENSIONS ARE IN MILLIMETERS 4. DIMENSIONS OF EXPOSED ...
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... FLASH SHALL NOT EXCEED 0.010" (0.254mm) PER SIDE Information furnished by Linear Technology Corporation is believed to be accurate and reliable. However, no responsibility is assumed for its use. Linear Technology Corporation makes no representation that the interconnection of its circuits as described herein will not infringe on existing patent rights. ...
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... Dual Current Limit LTC4258 Quad IEEE 802.3af Power over Ethernet Controller LTC4259A Quad IEEE 802.3af Power over Ethernet Controller Burst Mode is a registered trademark of Linear Technology Corporation. ThinSOT is a trademark of Linear Technology Corporation. Linear Technology Corporation 32 1630 McCarthy Blvd., Milpitas, CA 95035-7417 ...