LT3439 LINER [Linear Technology], LT3439 Datasheet
LT3439
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LT3439 Summary of contents
Page 1
... Protec- tion features include current limiting, undervoltage lock- out, thermal shutdown and cross conduction prevention circuitry. The LT3439 is available in a thermally enhanced 16-pin TSSOP with an exposed backside. , LTC and LT are registered trademarks of Linear Technology Corporation. OPTIONAL ...
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... COLA COLB Collector Collector Collector Collector Note 2: The LT3439E is guaranteed to meet performance specifications from Specifications over the – 125 C operating junction temperature range are assured by design, characterization and correlation with statistical process controls ...
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... TEMPERATURE ( C) 3439 G05 SYNC Pin Voltage Threshold vs Temperature 1.6 1.5 1.4 1.3 1.2 1.1 1.0 –50 – 125 150 TEMPERATURE ( C) 3439 G08 LT3439 100 125 150 3439 G03 100 125 150 3439 G06 100 125 150 3439 G09 sn3439 3439fs 3 ...
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... LT3439 CTIO S PGND (Pins 1, 16): Power ground is connected to the emitter of the power switches via an internal sense resis- tor. It has large currents flowing through it and should be connected to a good quality ground plane. COL A, COL B (Pins 3, 14): These are the open collectors of the output power switches ...
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... R SL eventually cause the transformer to saturate. Also, dur- ing the turn-off of the switches, the leakage inductance causes a large undesirable voltage spike. The LT3439 slew control feature addresses both of these concerns and is discussed in the Applications Information section. Slew Control Control of voltage and current slew rate is maintained via two feedback loops ...
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... The LT3439 provides control of two of the primary vari- ables for controlling EMI while switching inductive loads: switch voltage slew rate and switch current slew rate. The use of this part will reduce noise and EMI over conven- tional switch mode controllers ...
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... Slew Rate Setting Setting the LT3439 maximum slew rate is easy. The external resistor to ground on the R mum slew rate. To determine the maximum slew rate connect a 50k resistor pot with a 3.4k series resistance to the R pin ...
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... T AMB temperature and is the thermal resistance from junc- JA tion to ambient. The LT3439 comes in the 16-pin TSSOP with exposed backside package that has a very low junction-to-ambient thermal resistance ( ) of approximately 40 C/W. JA Transformer Design Table 1 lists recommended center tapped transformers for a variety of input voltage, output voltage and power combinations ...
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... Also, the losses in the transformer and the main switches have positive temperature coefficients elimi- is calculated PRI nating the potential for thermal runaway. The LT3439 can compensate for small circuit imbalances, however care should be taken to balance both sides of the circuit including transformer design and PCB layout. ...
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... LT3439 U U APPLICATIO S I FOR ATIO The primary inductance is then calculated 100 kHz OSC PRI 107 . A PRI I 15 714 . • . PRI Next, build a transformer with the calculated values of turns ratio and primary inductance. Minimize resistance in the windings. The turns ratio can be tweaked to get the specified output voltage ...
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... BSC (.0077 – .0118) 4. RECOMMENDED MINIMUM PCB METAL SIZE FOR EXPOSED PAD ATTACHMENT MILLIMETERS (INCHES) *DIMENSIONS DO NOT INCLUDE MOLD FLASH. MOLD FLASH SHALL NOT EXCEED 0.150mm (.006") PER SIDE LT3439 C7 BYP 0.01 F LT1761-BYP IN OUT + + R1 C9 GND ADJ ...
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... Linear Technology Corporation 12 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 FAX: (408) 434-0507 • • COLA • • LT3439 D2 14 COLB 4 C1: TDK C3216X5R1C475K R SL C3, C4: TDK C4532X5R1E156M PGND R SI C5: TEK C3216X5R1C475K 16.9k D1, D2: MBRA130LT3 1, 16 L1: COILCRAFT DO1608C-333 ...