LTC4267CDHC-3#TRPBF Linear Technology, LTC4267CDHC-3#TRPBF Datasheet
LTC4267CDHC-3#TRPBF
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LTC4267CDHC-3#TRPBF Summary of contents
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... Low Profi le 16-Pin SSOP or DFN Packages U APPLICATIO Phone Power Management n Wireless Access Points n Security Cameras n 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 – 0.1µF + – ...
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... T = 43.5°C/W JMAX JA EXPOSED PAD (PIN 17) MUST BE SOLDERED TO ELECTRICALLY ISOLATED PCB HEAT SINK ORDER INFORMATION LEAD FREE FINISH TAPE AND REEL LTC4267CDHC-3#PBF LTC4267CDHC-3#TRPBF LTC4267IDHC-3#PBF LTC4267IDHC-3#TRPBF LTC4267CGN-3#PBF LTC4267CGN-3#TRPBF LTC4267IGN-3#PBF LTC4267IGN-3#TRPBF LEAD BASED FINISH TAPE AND REEL LTC4267CDHC-3 LTC4267CDHC-3#TR LTC4267IDHC-3 ...
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ELECTRICAL CHARACTERISTICS temperature range, otherwise specifi cations are at T SYMBOL PARAMETER V Supply Voltage PORTN Maximum Operating Voltage Signature Range Classifi cation Range UVLO Turn-On Voltage UVLO Turn-Off Voltage V P Turn-On Voltage TURNON VCC V P Turn-Off Voltage ...
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LTC4267-3 ELECTRICAL CHARACTERISTICS temperature range, otherwise specifi cations are at T SYMBOL PARAMETER I Input Current Limit, High Level LIM_HI I Input Current Limit, Low Level LIM_LO f Oscillator Frequency OSC DC Minimum Switch On Duty Cycle ON(MIN) DC Maximum ...
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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 42673 G01 Input Current vs Input Voltage 3 ...
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LTC4267 TYPICAL PERFOR A CE CHARACTERISTICS Reference Voltage vs Temperature 812 VCC 808 804 800 796 792 788 –50 –30 – TEMPERATURE (°C) 42673 G10 Oscillator Frequency vs Supply Voltage ...
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W U TYPICAL PERFOR A CE CHARACTERISTICS Start-Up I Supply Current PVCC vs Temperature – 0.1V VCC TURNON –50 –30 – TEMPERATURE (°C) 42673 G17 ...
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LTC4267 CTIO S (DFN/SSOP) PGND (Pins 2, 15/Pins 16): Switching Regulator Negative Supply. This pin is the negative supply rail for the switching regulator controller and must be tied ...
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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 APPLICATIO S I FOR ATIO avoid corrupting the 25k signature resistor while also sav- ing board space and cost. In addition, the inrush current limit requirement of the IEEE 802.3af standard can cause large transient power dissipation ...
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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 APPLICATIO S I FOR ATIO LTC4267-3 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 high impedance state. LTC4267-3 V PORTP TO PSE UNDERVOLTAGE LOCKOUT CIRCUIT PGND V P PORTN INPUT LTC4267-3 ...
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LTC4267 APPLICATIO S I FOR ATIO LTC4267-3 THERMAL SHUTDOWN UVLO – TO PSE + + 1.125V – 300k V PORTN Figure 6. LTC4267-3 Power Good the LTC4267-3 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 LTC4267-3 ...
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LTC4267 APPLICATIO S I FOR ATIO LTC4267-3 PWM SHUTDOWN V /RUN ITH < < V ITHSHDN VCC TURNOFF (NOMINALLY 0.28V) LTC4267-3 PWM ENABLED ALL VOLTAGES WITH RESPECT TO PGND 42673 F08 Figure 8. LTC4267-3 Switching Regulator ...
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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 APPLICATIO S I FOR ATIO R2 75Ω C3 0.01µF 200V – FROM – PSE SPARE 5 ...
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U U APPLICATIO S I FOR ATIO Power Good Interface The PWRGD signal is controlled by a high voltage, open- drain transistor. The designer has the option of using this signal to enable the onboard switching regulator through the I ...
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LTC4267 APPLICATIO S I FOR ATIO on the cable from causing damage. However, if the V pin is shorted to V inside the PD while the capacitor PORTP is charged, current will fl ow through the parasitic body ...
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U U APPLICATIO S I FOR ATIO collector resistor of the optoisolator can be selected for an increase in bandwidth at the cost of a reduction in gain of this stage. Output Transformer Design Considerations Since the external feedback resistor ...
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LTC4267 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 ...
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U U APPLICATIO S I FOR ATIO Applications Employing a Third Transformer Winding A standard operating topology may employ a third wind- ing on the transformer’s primary side that provides power to the LTC4267-3 switching regulator via its P (Figure ...
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LTC4267 APPLICATIO S I FOR ATIO + V PORTP – 48 FROM P VCC PSE LTC4267-3 PGND – OUT PORTN Figure 12. Powering the LTC4267-3 Switching Regulator via the Shunt Regulator + PORTP ...
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U U APPLICATIO S I FOR ATIO In a nonisolated design, the LTC4267-3 incorporates an internal error amplifi er where the I a compensation point similar manner, a series RC network can be connected from I shown in ...
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LTC4267 APPLICATIO S I FOR ATIO OPTION 1: AUXILIARY POWER INSERTED BEFORE LTC4267-3 PD RJ45 + – – SPARE – SPARE 8 ISOLATED WALL ...
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U U APPLICATIO S I FOR ATIO If auxiliary power is applied directly to the LTC4267-3 switching regulator (bypassing the LTC4267-3 PD inter- face), a different set of tradeoffs arise. In the confi guration shown in option 2, the wall ...
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LTC4267 APPLICATIO S I FOR ATIO Layout Considerations for the LTC4267-3 The most critical layout considerations for the LTC4267-3 are the placement of the supporting external components associated with the switching regulator. Effi ciency, stabil- ity, and load ...
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U TYPICAL APPLICATIO S + –48V HD01 FROM DATA PAIR – + –48V HD01 FROM SPARE PAIR – * THREE 100µF CERAMICS Class 3 PD with 5V Nonisolated Power Supply 4.7µH 12µF 2.2µF 100V 100V 100k MMBTA42 BAS516 V P ...
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LTC4267-3 U TYPICAL APPLICATIO S 30 42673f ...
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... DIMENSIONS ARE IN (MILLIMETERS) 3. DRAWING NOT TO SCALE 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 representa- tion that the interconnection of its circuits as described herein will not infringe on existing patent rights. U × ...
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... High Power Single PSE Controller with Internal Switch 30W PSE Output Power, Internal MOSFET with Thermal Protection LTC4264 High Power PD Interface Controller LTC4267-1 IEEE 802.3af PD Interface with an Integrated Switching Regulator ThinSOT is a trademark of Linear Technology Corporation. Linear Technology Corporation 32 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 FAX: (408) 434-0507 ● ...