LTC4269IDKD-1#TRPBF Linear Technology, LTC4269IDKD-1#TRPBF Datasheet

IC PD/OPTO FLYBACK CTRLR 32-DFN

LTC4269IDKD-1#TRPBF

Manufacturer Part Number
LTC4269IDKD-1#TRPBF
Description
IC PD/OPTO FLYBACK CTRLR 32-DFN
Manufacturer
Linear Technology
Type
Power Over Ethernet (PoE)r
Datasheet

Specifications of LTC4269IDKD-1#TRPBF

Applications
Power Interface Switch for Power Over Ethernet (PoE) Devices
Voltage - Supply
14 V ~ 16 V
Operating Temperature
-40°C ~ 85°C
Mounting Type
Surface Mount
Package / Case
32-DFN
Current - Supply
1.35mA
Interface
IEEE 802.3af
Controller Type
Powered Device Interface Controller (PD)
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
FEATURES
n
n
n
n
n
n
n
n
n
n
n
n
APPLICATIONS
TYPICAL APPLICATION
n
n
n
n
n
25.5W IEEE 802.3at Compliant (Type 2) PD
Integrated State-of-the-Art Synchronous Flyback
Controller
– Isolated Power Supply Effi ciency >92%
– 88% Effi ciency Including Diode Bridge and
Flexible Integrated Auxiliary Power Support
Superior EMI Performance
Robust 100V 0.7Ω (Typ) Integrated Hot Swap MOSFET
IEEE 802.3at High Power Available Indicator
Integrated Signature Resistor and Programmable
Class Current
Undervoltage, Overvoltage and Thermal Protection
Short-Circuit Protection with Auto-Restart
Programmable Soft-Start and Switching Frequency
Complementary Power Good Indicators
Thermally Enhanced 7mm × 4mm DFN Package
VoIP Phones with Advanced Display Options
Dual-Radio Wireless Access Points
PTZ Security Cameras
RFID Readers
Industrial Controls
Hot Swap™ FET
SPARE PAIR
54V FROM
DATA PAIR
54V FROM
~
~
~
~
+
+
0.1μF
30.9Ω
383k
14k
V
R
SHDN
V
V
PORTP
PORTN
NEG
CLASS
PWRGD
+
SYNC
25W High Effi ciency PD Solution
10μH
10μF
UVLO
GND
CONTROLLER
TO MICRO
OSC
T2P
33pF
2.2μF
PGDLY
LTC4269-1
12k
27.4k
3.01k
t
ON
FB
100k
DESCRIPTION
The LTC
controller and switching regulator intended for high
power IEEE 802.3at and 802.3af applications. The
LTC4269-1 is targeted for high effi ciency, single and
multioutput applications from 10W to 25W. By support-
ing both 1-event and 2-event classifi cations, as defi ned
by the IEEE, the LTC4269-1 can be used in a wide range
of product confi gurations.
The LTC4269-1 synchronous, current mode, fl yback con-
troller generates multiple supply rails in a single conversion
step providing for the highest system effi ciency while main-
taining tight regulation across all outputs. The LTC4269-1
includes Linear Technology’s patented No-Opto feedback
topology to provide full IEEE 802.3 isolation without the
need of an opto-isolator circuit. A true soft-start function
allows graceful ramp-up of all output voltages.
All Linear Technology PD solutions include a shutdown
pin to provide fl exible auxiliary power options. The
LTC4269-1 can accommodate adaptor voltages from 18V
to 60V and supports both PoE or aux dominance options.
The LTC4269-1 is available in a space saving 32-pin DFN
package.
L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear
Technology Corporation. Hot Swap is a trademark of Linear Technology Corporation. All other
trademarks are the property of their respective owners. Protected by U.S. Patents, including
5841643.
ENDLY
V
CC
38.3k
V
39k
IN
R
CMP
PG
1.21k
®
10μF
Synchronous No-Opto
4269-1 is an integrated Powered Device (PD)
SENSE
SENSE
C
CMP
V
CMP
SG
0.1μF
+
IEEE 802.3at PD with
Flyback Controller
10nF
33mΩ
1μF
2.2nF
0.18μH
47μF
LTC4269-1
42691 TA01a
+
100μF
5V
5A
42691fb
1

Related parts for LTC4269IDKD-1#TRPBF

LTC4269IDKD-1#TRPBF Summary of contents

Page 1

... The LTC4269-1 is available in a space saving 32-pin DFN package. L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear Technology Corporation. Hot Swap is a trademark of Linear Technology Corporation. All other trademarks are the property of their respective owners. Protected by U.S. Patents, including 5841643. 25W High Effi ...

Page 2

... LTC4269CDKD-1#PBF LTC4269CDKD-1#TRPBF LTC4269IDKD-1#PBF LTC4269IDKD-1#TRPBF Consult LTC Marketing for parts specifi ed with wider operating temperature ranges. *The temperature grade is identifi label on the shipping container. For more information on lead free part marking, go to: For more information on tape and reel specifi cations, go to: ...

Page 3

ELECTRICAL CHARACTERISTICS temperature range, otherwise specifi cations are at T PARAMETER Interface Controller (Note 4) Operating Input Voltage Signature Range Classifi cation Range ON Voltage OFF Voltage Overvoltage Lockout ON/OFF Hysteresis Window Signature/Class Hysteresis Window Reset Threshold Supply Current Supply ...

Page 4

LTC4269-1 ELECTRICAL CHARACTERISTICS temperature range, otherwise specifi cations are at T PARAMETER PWM Controller (Note 10) Power Supply V Turn-On Voltage CC(ON) V Turn-Off Voltage CC(OFF) V Hysteresis CC V Shunt Clamp CC V Supply Current ...

Page 5

ELECTRICAL CHARACTERISTICS temperature range, otherwise specifi cations are at T PARAMETER Load Compensation Load Compensation to V Offset Voltage SENSE Feedback Pin Load Compensation Current UVLO Function UVLO Pin Threshold (V ) UVLO UVLO Pin Bias Current Note 1: Stresses ...

Page 6

LTC4269-1 TYPICAL PERFORMANCE CHARACTERISTICS Input Current vs Input Voltage 25k Detection Range 0 25°C A 0.4 0.3 0.2 0 VOLTAGE (V) PORTP 42691 G01 Signature Resistance vs Input Voltage 28 V ...

Page 7

TYPICAL PERFORMANCE CHARACTERISTICS V and V CC(ON) CC(OFF) vs Temperature CC(ON CC(OFF –50 – 100 TEMPERATURE (°C) 42691 G10 SENSE Voltage vs Temperature 110 FB ...

Page 8

LTC4269-1 TYPICAL PERFORMANCE CHARACTERISTICS Feedback Amplifi er Output Current 125°C 25°C 50 –40° –10 –30 –50 –70 0.9 1 1.1 1.2 1.3 1.4 V (V) FB 42691 G19 Feedback Amplifi er Voltage Gain vs ...

Page 9

TYPICAL PERFORMANCE CHARACTERISTICS Minimum PG On-Time vs Temperature 340 R = 158k tON(MIN) 330 320 310 300 290 280 270 260 –50 – 100 TEMPERATURE (°C) 42691 G28 PIN FUNCTIONS SHDN (Pin 1): Shutdown Input. Use ...

Page 10

LTC4269-1 PIN FUNCTIONS the V voltage and thus limits peak current until soft- CMP start is complete. The ramp time is approximately 70ms per μF of capacitance. Leave SFST open if not using the soft-start function. OSC (Pin 15): Oscillator. ...

Page 11

BLOCK DIAGRAM SHDN 1 T2P 2 R CLASS PORTN 5 V PORTN UVLO CC + – 1.237V 15.3V REFERENCE (V UVLO 18 OSC 15 OSCILLATOR SYNC 13 ...

Page 12

LTC4269-1 APPLICATIONS INFORMATION OVERVIEW Power over Ethernet (PoE) continues to gain popularity as more products are taking advantage of having DC power and high speed data available from a single RJ45 connector. As PoE continues to grow in the marketplace, ...

Page 13

APPLICATIONS INFORMATION Table 1. LTC4269-1 Modes of Operation as a Function of Input Voltage V –V (V) LTC4269-1 MODES OF OPERATION PORTP PORTN 0V to 1.4V Inactive (Reset After 1st Classifi cation Event) 1.5V to 9.8V 25k Signature Resistor Detection ...

Page 14

LTC4269-1 APPLICATIONS INFORMATION SIGNATURE CORRUPT OPTION In some designs that include an auxiliary power option necessary to prevent a PD from being detected by a PSE. The LTC4269-1 signature resistance can be corrupted with the SHDN pin (Figure ...

Page 15

APPLICATIONS INFORMATION 50 40 1st CLASS 30 2nd CLASS DETECTION V1 1st MARK 2nd MARK DETECTION V2 INRUSH 1st CLASS 2nd CLASS 40mA DETECTION V1 1st MARK 2nd MARK DETECTION INRUSH = dt C1 ...

Page 16

LTC4269-1 APPLICATIONS INFORMATION To control the power-on surge currents in the system, the LTC4269-1 provides a fi xed inrush current, allowing C1 to ramp up to the line voltage in a controlled manner. The LTC4269-1 keeps the PD inrush current ...

Page 17

APPLICATIONS INFORMATION from commencing operation before the PD interface completely charges the reservoir capacitor, C1. The active low PWRGD pin connects to an internal, open- drain MOSFET referenced to V PORTN indicator bit when power good is declared and active. ...

Page 18

LTC4269-1 APPLICATIONS INFORMATION Input Diode Bridge Figure 2 shows how two diode bridges are typically con- nected application. One bridge is dedicated to the data pair while the other bridge is dedicated to the spare pair. The ...

Page 19

APPLICATIONS INFORMATION Transient Voltage Suppressor The LTC4269-1 specifi absolute maximum voltage of 100V and is designed to tolerate brief overvoltage events. However, the pins that interface to the outside world can routinely see excessive peak voltages. To protect ...

Page 20

... PoE to auxiliary power when auxiliary power is applied, however, the removal of auxiliary power to PoE power is not seamless unused, connect Contact Linear Technology applications support for detail information on implementing a custom auxiliary power supply. IEEE 802.3at SYSTEM POWER-UP REQUIREMENT Under the IEEE 802.3at standard must operate ...

Page 21

APPLICATIONS INFORMATION SWITCHING REGULATOR OVERVIEW The LTC4269-1 includes a current mode converter designed specifi cally for use in an isolated fl yback topology employing synchronous rectifi cation. The LTC4269-1 operation is similar to traditional current mode switchers. The major difference ...

Page 22

LTC4269-1 APPLICATIONS INFORMATION LTC4269-1 FEEDBACK AMP 1.237V – + COLLAPSE DETECT ENABLE Figure 10a. LTC4269-1 Switching Regulator Feedback Amplifi er PRIMARY-SIDE MOSFET DRAIN VOLTAGE VOLTAGE SG VOLTAGE Figure 10b. LTC4269-1 Switching Regulator ...

Page 23

APPLICATIONS INFORMATION Enable Delay Time (ENDLY) The fl yback pulse appears when the primary-side switch shuts off. However, it takes a fi nite time until the transformer primary-side voltage waveform represents the output voltage. This is partly due to rise ...

Page 24

LTC4269-1 APPLICATIONS INFORMATION in sensed output voltage, compensating for the IR drops. Assuming relatively fi xed power supply effi ciency, Eff, power balance gives Eff • P OUT IN V • Eff • V • I ...

Page 25

APPLICATIONS INFORMATION Note the use of the external feedback resistive divider ratio to set output voltage provides the user additional freedom in selecting a suitable transformer turns ratio. Turns ratios that are the simple ratios of small integers; e.g., 1:1, ...

Page 26

LTC4269-1 APPLICATIONS INFORMATION A fi nal note—the susceptibility of the system to bistable behavior is somewhat a function of the load current/ voltage characteristics. A load with resistive—i.e V/R behavior—is the most apt to be bistable. Capacitive loads ...

Page 27

APPLICATIONS INFORMATION in an abrupt increase in inductor ripple current and, consequently, output voltage ripple. Do not allow the core to saturate! The maximum peak primary current occurs at minimum ⎛ MIN = I ...

Page 28

LTC4269-1 APPLICATIONS INFORMATION Selecting the Load Compensation Resistor The expression for R was derived in the Operation CMP section as • 1− DC SENSE = K1• R • R1• N CMP ESR + R DS(ON) Continuing the ...

Page 29

APPLICATIONS INFORMATION trace length and area to minimize stray capacitance and potential noise pick-up. You can synchronize the oscillator frequency to an external frequency. This is done with a signal on the SYNC pin. Set the LTC4269-1 frequency 10% slower ...

Page 30

LTC4269-1 APPLICATIONS INFORMATION Primary Gate Delay Time (PGDLY) Primary gate delay is the programmable time from the turn-off of the synchronous MOSFET to the turn-on of the primary-side MOSFET. Correct setting eliminates overlap between the primary-side switch and secondary-side syn- ...

Page 31

APPLICATIONS INFORMATION If we wanted a V -referred trip point of 36V, with 1.8V IN (5%) of hysteresis (on at 36V, off at 34.2V): 1. 529k, use 523k R A 3.4µA 523k = = 18.5k, use 18.7k R ...

Page 32

LTC4269-1 APPLICATIONS INFORMATION The LTC4269-1 has an internal clamp on V mately 19.5V. This provides some protection for the part in the event that the switcher is off (UVLO low) and the V node is pulled high ...

Page 33

APPLICATIONS INFORMATION Short-Circuit Conditions Loss of current limit is possible under certain conditions such as an output short-circuit. If the duty cycle exhibited by the minimum on-time is greater than the ratio of secondary winding voltage (referred-to-primary) divided by input ...

Page 34

LTC4269-1 APPLICATIONS INFORMATION For each secondary-side power MOSFET, the BV be greater than: BV ≥ • N DSS OUT IN(MAX) SP Choose the primary-side MOSFET R gate drive voltage (7.5V). The secondary-side MOSFET gate drive voltage depends ...

Page 35

APPLICATIONS INFORMATION The LTC4269-1 gate drives will clamp the max gate voltage to roughly 7.5V, so you can safely use MOSFETs with maximum V of 10V and larger. GS Synchronous Gate Drive There are several different ways to drive the ...

Page 36

... This heat sink should be electrically connected to GND. For optimum thermal performance, make the heat sink as large as possible. Voltages can be as large as 57V for PoE applications, so high voltage layout techniques should be employed. The SHDN SwitcherCAD is a trademark of Linear Technology Corporation. and V ) PORTN PORTP ...

Page 37

APPLICATIONS INFORMATION pin should be separated from other high voltage pins, like avoid the possibility of leakage currents PORTP NEG shutting down the LTC4269-1. If not used, tie SHDN The load capacitor ...

Page 38

LTC4269-1 TYPICAL APPLICATIONS 38 42691fb ...

Page 39

TYPICAL APPLICATIONS V PORTP + 48V AUXILLIARY POWER – B1100 8 PLCS 107k 36V 54V FROM PDZ36B DATA PAIR 10k BSS63LT1 S1B BAS21 SMAJ58A 30.9Ω 54V FROM 0.1μF 24k SPARE PAIR 100V T1: PCA ELECTRONICS, EPC3409G-LF OR PULSE, PA2369NL T2: ...

Page 40

LTC4269-1 TYPICAL APPLICATIONS V PORTP + 48V AUXILLIARY POWER – B1100 8 PLCS 107k 36V 54V FROM PDZ36B DATA PAIR 10k BSS63LT1 S1B BAS21 SMAJ58A 30.9Ω 54V FROM 0.1μF 24k SPARE PAIR 100V T1: PCA ELECTRONICS, EPC3410G-LF OR PULSE, PA2467NL ...

Page 41

TYPICAL APPLICATIONS V PORTP + 48V AUXILLIARY POWER – B1100 8 PLCS 107k 36V 54V FROM PDZ36B DATA PAIR 10k BSS63LT1 S1B BAS21 SMAJ58A 30.9Ω 54V FROM 0.1μF 24k SPARE PAIR 100V T1: PCA ELECTRONICS, EPC3408G-LF OR PULSE, PA2466NL T2: ...

Page 42

LTC4269-1 PACKAGE DESCRIPTION 4.50 ± 0.05 6.43 ±0.05 2.65 ±0.05 3.10 ± 0.05 0.40 BSC 6.00 REF RECOMMENDED SOLDER PAD LAYOUT APPLY SOLDER MASK TO AREAS THAT ARE NOT SOLDERED 7.00 ±0.10 PIN 1 TOP MARK (SEE NOTE 6) 0.200 ...

Page 43

... Added Text Clarifying Connecting PWRGD Pin to UVLO Pin in Complementary Power Good Section of the Applications Information Section 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. LTC4269-1 ...

Page 44

... IEEE 802.3af PD Interface with an Integrated Switching Regulator LTC4268-1 High Power PD with Synchronous No-Opto Flyback Controller LTC4269-2 IEEE 802.3af/IEEE 802.3at PD with Synchronous Forward Controller ThinSOT is a trademark of Linear Technology Corporation. 44 Linear Technology Corporation 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 FAX: (408) 434-0507 ● COMMENTS ...

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