LTC3778EF#PBF Linear Technology, LTC3778EF#PBF Datasheet
LTC3778EF#PBF
Specifications of LTC3778EF#PBF
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LTC3778EF#PBF Summary of contents
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... Soft-start capability for supply sequencing is accom- plished using an external timing capacitor. The regulator current limit level is user programmable. Wide supply range allows operation from 4V to 36V at the input and from 0. (0.9)V , LTC and LT are registered trademarks of Linear Technology Corporation trademark of Linear Technology Corporation. SENSE V ...
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LTC3778 ABSOLUTE AXI U RATI GS (Note 1) Input Supply Voltage ( )..................36V to – 0. Boosted Topside Driver Supply Voltage (BOOST) ................................................... 42V to – 0.3V + SENSE , SW Voltage.................................... 36V ...
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ELECTRICAL CHARACTERISTICS temperature range, otherwise specifications are T SYMBOL PARAMETER V RUN Pin Start Threshold RUN/SS(ON) V RUN Pin Latchoff Enable Threshold RUN/SS(LE) V RUN Pin Latchoff Threshold RUN/SS(LT) I Soft-Start Charge Current RUN/SS(C) I Soft-Start Discharge Current RUN/SS(D) V ...
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LTC3778 W U TYPICAL PERFOR A CE CHARACTERISTICS Transient Response V OUT 50mV/DIV I L 5A/DIV 20 s/DIV 3778 G01 LOAD STEP 0A TO 10A V = 15V 2.5V OUT FCB = 0V FIGURE 1 CIRCUIT Efficiency ...
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W U TYPICAL PERFOR A CE CHARACTERISTICS On-Time vs I Current ON 10k VON 1k 100 100 I CURRENT ( A) ON 3778 G20 Current Limit Foldback 150 RNG 125 100 ...
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LTC3778 W U TYPICAL PERFOR A CE CHARACTERISTICS Input and Shutdown Currents vs Input Voltage 1200 EXTV OPEN CC 1000 800 SHUTDOWN 600 400 200 EXTV = INPUT VOLTAGE ...
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CTIO S RUN/SS (Pin 1): Run Control and Soft-Start Input. A capacitor to ground at this pin sets the ramp time to full output current (approximately 3s/ F) and the time delay for overcurrent latchoff ...
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LTC3778 CTIO AL DIAGRA OUT 0.7V 2.4V V VON t = (10pF ION S 20k + + I CMP – – 1.4V V RNG 4 ...
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U OPERATIO Main Control Loop The LTC3778 is a current mode controller for DC/DC step-down converters. In normal operation, the top MOSFET is turned on for a fixed interval determined by a one-shot timer OST. When the top MOSFET is ...
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LTC3778 U U APPLICATIO S I FOR ATIO The basic LTC3778 application circuit is shown in Figure 1. External component selection is primarily de- termined by the maximum load current and begins with the selection of the sense resistance and ...
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U U APPLICATIO S I FOR ATIO The term is a normalization factor (unity accounting for the significant variation in on-resistance with temperature, typically about 0.4 shown in Figure 2. For a maximum junction ...
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LTC3778 U U APPLICATIO S I FOR ATIO load current increases. By lengthening the on-time slightly as current increases, constant frequency operation can be maintained. This is accomplished with a resistive divider from the I pin to the V pin ...
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U U APPLICATIO S I FOR ATIO commonly used for design because even significant deviations do not offer much relief. Note that ripple current ratings from capacitor manufacturers are often based on only 2000 hours of life which makes it ...
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LTC3778 U U APPLICATIO S I FOR ATIO + OPTIONAL LTC3778 EXTV CC EXTV SW CC CONNECTION R4 5V < V < 7V OUT2 FCB R3 BG SGND PGND Figure 4. Secondary Output Loop and EXTV Fault ...
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U U APPLICATIO S I FOR ATIO EXTV Connection CC The EXTV pin can be used to provide MOSFET gate drive CC and control power from the output or another external source during normal operation. Whenever the EXTV pin is ...
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LTC3778 U U APPLICATIO S I FOR ATIO Overcurrent latchoff operation is not always needed or desired. Load current is already limited during a short- circuit by the current foldback circuitry and latchoff operation can prove annoying during troubleshooting. The ...
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... The I pin external components shown in Figure 7 TH will provide adequate compensation for most applica- tions. For a detailed explanation of switching control loop theory see Linear Technology Application Note 76. Design Example As a design example, take a supply with the following specifications 28V (15V nominal), V ...
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LTC3778 U U APPLICATIO S I FOR ATIO 100k R3 R4 11k 39k 500pF C 20k C C2 100pF 12. 400k 10 R2 ...
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... I TH NOM ( Solving for the required values of the resistors The active voltage positioned circuit is shown in Figure 8. Refer to Linear Technology Design Solutions 10 for addi- to ground and R VP2 tional information about output voltage positioning RUN/SS BOOST D B LTC3778 2 19 CMDSH-3 V ...
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LTC3778 U U APPLICATIO S I FOR ATIO PC Board Layout Checklist When laying out a PC board follow one of the two sug- gested approaches. The simple PC board layout requires a dedicated ground plane layer. Also, for higher ...
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U U APPLICATIO S I FOR ATIO • Segregate the signal and power grounds. All small signal components should return to the SGND pin at one point which is then tied to the PGND pin close to the source of ...
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LTC3778 U TYPICAL APPLICATIO S Intel Compatible Tualatin Mobile CPU Power Supply with AVP 3 V RON 3.3V 2N7002 100k 100k C2, 0. 100 1k V OUT ...
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... FLASH SHALL NOT EXCEED .254mm (.010") 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 represen- tation that the interconnection of its circuits as described herein will not infringe on existing patent rights. ...
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... Intel Compatible, Wide Operating Range Controller with Internal Op Amp LTC3716 High Efficiency, 2-Phase Synchronous Step-Down Controller with 5-Bit Mobile VID Burst Mode and ThinSOT are trademarks of Linear Technology Corporation. Linear Technology Corporation 24 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 FAX: (408) 434-0507 ...