LTC1778EGN-1 Linear Technology, LTC1778EGN-1 Datasheet
LTC1778EGN-1
Specifications of LTC1778EGN-1
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LTC1778EGN-1 Summary of contents
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... The regulator current limit level is user program- mable. 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 All other trademarks are the property of their respective owners ...
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... FCB I = 30µ (LTC1778- 15µ (LTC1778- 180µ EXTV Peak Currents .................... EXTV RMS Currents .............. 50mA CC CC ORDER PART TOP VIEW NUMBER 16 BOOST 15 TG LTC1778EGN PGND INTV CC GN PART MARKING EXTV CC 17781 GN PACKAGE = 130° MIN TYP MAX 900 2000 15 30 ● ...
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ELECTRICAL CHARACTERISTICS temperature range, otherwise specifications are T SYMBOL PARAMETER t Minimum Off-Time OFF(MIN) V Maximum Current Sense Threshold SENSE(MAX) V – V PGND SW V Minimum Current Sense Threshold SENSE(MIN) V – V PGND SW ∆V Output Overvoltage Fault ...
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LTC1778/LTC1778 TYPICAL PERFOR A CE CHARACTERISTICS Transient Response V OUT 50mV/DIV I L 5A/DIV 20µs/DIV 1778 G01 LOAD STEP 0A TO 10A V = 15V 2.5V OUT FCB = 0V FIGURE 9 CIRCUIT Efficiency vs ...
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W U TYPICAL PERFOR A CE CHARACTERISTICS Current Sense Threshold vs I Voltage TH 300 RNG 200 1.4V 1V 0.7V 100 0.5V 0 –100 –200 0 1.0 1.5 2.0 2.5 3.0 0.5 I VOLTAGE (V) TH 1778 ...
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LTC1778/LTC1778 TYPICAL PERFOR A CE CHARACTERISTICS Error Amplifier g vs Temperature m 2.0 1.8 1.6 1.4 1.2 1.0 –50 – 100 125 TEMPERATURE (°C) 1778 G13 EXTV Switch Resistance CC vs Temperature 10 8 ...
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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/µF) and the time delay for overcurrent latchoff (see ...
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LTC1778/LTC1778 CTIO AL DIAGRA 0.7V 2. VON t = (10pF ION S Q 20k + + I I CMP – – 1.4V V ...
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U OPERATIO Main Control Loop The LTC1778 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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LTC1778/LTC1778 APPLICATIO S I FOR ATIO The basic LTC1778 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 with temperature, typically about 0.4%/°C as shown in Figure 2. For a maximum junction temperature of 100°C, using a value ρ = 1.3 is reasonable. T The power dissipated by the top and ...
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LTC1778/LTC1778 APPLICATIO S I FOR ATIO Because the voltage at the I pin is about 0.7V, the ON current into this pin is not exactly inversely proportional especially in applications with lower input voltages. IN ...
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U U APPLICATIO S I FOR ATIO ripple. Highest efficiency operation is obtained at low frequency with small ripple current. However, achieving this requires a large inductor. There is a tradeoff between component size, efficiency and operating frequency. A reasonable ...
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LTC1778/LTC1778 APPLICATIO S I FOR ATIO but an additional ceramic capacitor in parallel is recom- mended to reduce the effect of their lead inductance. Top MOSFET Driver Supply ( external bootstrap capacitor C connected ...
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U U APPLICATIO S I FOR ATIO INTV Regulator CC An internal P-channel low dropout regulator produces the 5V supply that powers the drivers and internal circuitry within the LTC1778. The INTV CC 50mA RMS and must be bypassed to ...
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LTC1778/LTC1778 APPLICATIO S I FOR ATIO reduces the start delay while allowing C slowly for the soft-start function. After the controller has been started and given adequate time to charge up the output capacitor, C short-circuit timer. After ...
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U U APPLICATIO S I FOR ATIO Other losses, including C ESR loss, Schottky diode D1 OUT conduction loss during dead time and inductor core loss generally account for less than 2% additional loss. When making adjustments to improve efficiency, ...
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LTC1778/LTC1778 APPLICATIO S I FOR ATIO C is chosen for an RMS current rating of about 85°C. The output capacitors are chosen for a low ESR of 0.013Ω to minimize output voltage changes due to ...
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U U APPLICATIO S I FOR ATIO When laying out a printed circuit board, without a ground plane, use the following checklist to ensure proper opera- tion of the controller. These items are also illustrated in Figure 10. • Segregate ...
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LTC1778/LTC1778-1 U TYPICAL APPLICATIO 0.1µF 1 RUN/ 100k 11k 39k 2 PGOOD 3 V RNG 4 FCB 680pF C 20k 100pF 6 SGND ...
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U TYPICAL APPLICATIO 0.1µF LTC1778-1 1 RUN/ RNG 4 FCB C 1nF 47k 220pF 6 SGND 100pF 8 V ...
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LTC1778/LTC1778-1 U TYPICAL APPLICATIO 0.1µF LTC1778-1 1 RUN/ RNG 4 FCB 4700pF C 10k 100pF 6 SGND 10k 8 V ...
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... FLASH SHALL NOT EXCEED 0.010" (0.254mm) 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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... LTC3778 Low Synchronous Step-Down Controller OUT SENSE ® LT 3800 60V Synchronous Step-Down Controller Burst Mode is a registered trademark of Linear Technology Corporation. Linear Technology Corporation 24 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 FAX: (408) 434-0507 ● Typical Application 2.5V/3A at 1.4MHz D B CMDSH-3 ...