LTC3805-5 Linear Technology, LTC3805-5 Datasheet
LTC3805-5
Related parts for LTC3805-5
LTC3805-5 Summary of contents
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... V can be powered directly from a low impedance DC voltage from 4.7V to 8.8V. The LTC3805-5 is available in the 10-lead MSOP package and the 3mm × 3mm DFN package. , LT, LTC and LTM are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. ...
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... Operating Temperature Range E-Grade ................................................–40°C to 85°C * I-Grade ............................................... –40°C to 125°C CC Junction Temperature ........................................... 125°C Storage Temperature Range ...................–65°C to 125°C Lead Temperature (Soldering, 10 sec) LTC3805EMSE-5 Only ....................................... 300°C *LTC3805-5 internal clamp circuit regulates V 10 GATE ...
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... OC Note 4: Dynamic supply current is higher due to the gate charge being delivered at the switching frequency. Note 5: The LTC3805-5 is tested in a feedback loop that servos V output of the error amplifi er while maintaining I current limit range. Note 6: Peak current sense voltage is reduced dependent on duty cycle and an optional external resistor in series with the SENSE pin ...
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... LTC3805-5 TYPICAL PERFORMANCE CHARACTERISTICS Reference Voltage vs Temperature www.datasheet4u.com 812 808 804 800 796 792 788 –50 – TEMPERATURE (°C) Oscillator Frequency vs Supply Voltage 203 202 201 R = 124kΩ FS 200 199 198 197 196 (V) CC RUN Hysteresis Current vs Temperature 5 ...
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... TEMPERATURE (°C) 38055 G12 2.1 2.0 1.9 1.8 1.7 1.6 1 100 125 TEMPERATURE (°C) 38055 G15 LTC3805-5 V Shunt Regulator Voltage CC vs Temperature 9.60 9.55 V CLAMP25mA 9.50 9.45 9.40 9.35 9.30 V CLAMP1mA 9.25 9.20 75 100 125 –50 – TEMPERATURE (°C) 38055 G10 Internal Soft-Start Time vs Temperature 1 ...
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... LTC3805-5 PIN FUNCTIONS SSFLT (Pin 1): Soft-Start Pin. A capacitor placed from this pin to GND (Exposed Pad) controls the rate of rise of converter output voltage during start-up. This capacitor is www.datasheet4u.com also used for time out after a fault prior to restart. I (Pin 2): Error Amplifi er Compensation Point. Normal TH operating voltage range is clamped between 0 ...
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... GND SOFT-START RAMP SHUTDOWN SOFT-START FAULT OVERCURRENT COMPARATOR + – CURRENT COMPARATOR – ERROR AMPLIFIER + 20mV OSCILLATOR 1. LTC3805-5 4 RUN UNDERVOLTAGE LOCKOUT GATE SWITCHING R DRIVER LOGIC AND Q BLANKING S CIRCUIT SLOPE COMP CURRENT RAMP ISENSE SYNC 6 GATE 10 7 38055 BD 38055fa 7 ...
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... LTC3805-5 OPERATION The LTC3805 programmable-frequency current mode controller for fl yback, boost and SEPIC DC/DC convert- ers. The LTC3805-5 is designed so that none of its pins www.datasheet4u.com need to come in contact with the input or output voltages of the power supply circuit of which part, allowing the conversion of voltages well beyond the LTC3805-5’ ...
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... Figure 1. Operation in fault timeout is discussed in a subsequent section. During shutdown the LTC3805-5 draws only a small 40μA current. The undervoltage lockout (UVLO) mechanism prevents the LTC3805-5 from trying to drive the external MOSFET gate with insuffi cient voltage on the V at the V pin must initially exceed V CC able LTC3805-5 operation ...
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... V as the shunt regulator is not forced to sink more than 25mA. The shunt regulator is always active, even when the LTC3805 shutdown, since it serves the vital function of protecting the V shunt regulator permits the use of a wide variety of power- ing schemes for the LTC3805-5 even from high voltage sources that exceed the LTC3805-5’ ...
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... Note that this topology is very power- ful because, by appropriate choice of transformer turns ratio, the output voltage can be chosen without regard to the value of the input voltage or the V the LTC3805-5. The number of turns in the bias winding is chosen according to N BIAS ...
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... To introduce further user-programmable hysteresis, the LTC3805-5 sources 5μA out of the RUN pin when operation of LTC3805-5 is enabled result, the falling threshold for the RUN pin also depends on the value of R1 and can be programmed by the user. The falling threshold for V ...
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... Oscillator Synchronization The oscillator may be synchronized to an external clock by connecting the synchronization signal to the SYNC pin. The LTC3805-5 oscillator and turn-on of the switch are synchronized to the rising edge of the external clock. The FB frequency of the external sync signal must be ±33% with ...
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... SENSE Note: LTC3805-5 enforces 6% < Duty Cycle < 80%. A good starting value for R in current comparator threshold at 80% duty cycle. Designs that do not operate at greater than 50% duty cycle do not need slope compensation and may replace R with a direct connection ...
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... In some cases it may be desirable to increase the trip threshold even further. In this strategy, the converter is allowed to operate all the way down to minimum duty cycle at which point the cycle-by-cycle current limit of LTC3805-5 produces an overcurrent trip at an output OC(CRIT) can be used to reduce the trip threshold and ...
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... If there is an overcurrent fault detected on the OC pin, the LTC3805-5 enters a shutdown mode while a 2μA current discharges the voltage on the SSFLT pin from 4.75V to about 0.7V. The fault timeout t t FTO EXT At this point, the LTC3805-5 attempts a restart ...
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... Figure 8. 5.5V-40V to 12V/2A SEPIC Converter Effi ciency and Power Loss vs Load Current 100 90 EFFICIENCY POWER LOSS 0.01 0.1 1 LOAD CURRENT (A) LTC3805-5 4.56μH BH510-1009 • • BAS516 T1 10μF D1 301W 50V PDS760 V OUT 12V C 2A OUT 47μF 16V Q1 HAT2266 ...
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... LTC3805-5 TYPICAL APPLICATIONS + V IN 18V TO 72V 2.2μF 2.2μF 221k 100V 100V www.datasheet4u.com PDZ6.8B 6.8V – 0.022μ LTC3805 SSFLT GATE 221k RUN SENSE GND SYNC 15.8k 75k 11 Figure 9. Isolated Telecom Supply: 18V-72V Input to 3.3V/3A Output ...
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... MOLD FLASH, PROTRUSIONS OR GATE BURRS SHALL NOT EXCEED 0.152mm (.006") PER SIDE 4. DIMENSION DOES NOT INCLUDE INTERLEAD FLASH OR PROTRUSIONS. INTERLEAD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.152mm (.006") PER SIDE 5. LEAD COPLANARITY (BOTTOM OF LEADS AFTER FORMING) SHALL BE 0.102mm (.004") MAX LTC3805 0.115 0.38 0.10 TYP ...
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... LTC3805-5 TYPICAL APPLICATION 5V-40V to 12V/1A Nonisolated Flyback Converter 40V www.datasheet4u.com 2.2μF 2.2μF 10k 100V 100V MMBTA42 6.8V PDZ6. 100pF 0.1μ 470pF 4.7μF 20k U1 LTC3805 SSFLT GATE RUN I V SENSE ...