LTC1873EG#TR Linear Technology, LTC1873EG#TR Datasheet

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... Each channel can be enabled independently; with both chan- nels disabled, the LTC1873 shuts down and supply current drops below 100 A. , LTC and LT are registered trademarks of Linear Technology Corporation. Burst Mode is a trademark of Linear Technology Corporation. Low Cost Desktop CPU Supply with RDRAM Keepalive ...

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LTC1873 ABSOLUTE AXI U RATI GS (Note 1) Supply Voltage V CC ........................................................................................... BOOST n ............................................................... 15V BOOST n – .................................................... 7V Input Voltage SW n .......................................................... – VID n ....................................................... – ...

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ELECTRICAL CHARACTERISTICS The denotes specifications which apply over the full operating temperature range, otherwise specifications are unless otherwise specified. (Note 4) CC SYMBOL PARAMETER Switching Characteristics V Oscillator Amplitude OSC f Oscillator ...

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LTC1873 W U TYPICAL PERFOR A CE CHARACTERISTICS Efficiency vs Load Current 100 3.3V OUT V = 2.5V OUT 1.6V OUT LOAD CURRENT (A) 1873 ...

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CTIO S PV (Pin 1): Driver Power Supply Input power to the two BG n output drivers. PV connected to a voltage high enough to fully turn on the external MOSFETs QB1 and ...

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LTC1873 CTIO S VID n pin includes an on-chip 40k series with a diode (see Block Diagram). V (Pin 18): Power Supply Input. All internal circuits CC except the output drivers are powered from this ...

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W BLOCK DIAGRA V CC 90% DUTY CYCLE OSC 550kHz 3.5 A SOFT RUN/SS1,2 START COMP1,2 I LIM – I MAX1,2 800mV SHUTDOWN TO THIS CONTROLLER 500mV OTHER CONTROLLER U U APPLICATIO S I FOR ATIO ...

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LTC1873 U U APPLICATIO S I FOR ATIO Table 1. VID Inputs and Corresponding Output Voltage for Channel 1 CODE VID4 VID3 VID2 VID1 00000 GND GND GND GND 00001 GND GND GND GND 00010 GND GND GND Float 00011 ...

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U U APPLICATIO S I FOR ATIO factor of 3.75. The reduced input ripple voltage also means less power is lost in the input power path, which could include batteries, switches, trace/connector resistances and protection circuitry. Improvements in both conducted ...

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LTC1873 U U APPLICATIO S I FOR ATIO Switching Architecture Each half of the LTC1873 is designed to operate as a synchronous buck converter (Figure 1). Each channel includes two high power MOSFET gate drivers to control external N-channel MOSFETs ...

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U U APPLICATIO S I FOR ATIO pin. The output is connected to COMP, which is in turn connected to the soft-start circuitry and from there to the PWM generator. Unlike many regulators that use a resistor divider con- nected ...

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LTC1873 U U APPLICATIO S I FOR ATIO Each RUN/SS pin shuts down its half of the LTC1873 when it falls below about 0.5V (Figure 4). Between 0.5V and about 1V, that half is active, but the maximum duty cycle ...

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U U APPLICATIO S I FOR ATIO enhance loop stability. Larger overloads cause the soft- start capacitor to pull down quickly, protecting the output components from damage. The current limit g includes a clamp to prevent it from pulling RUN/SS ...

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LTC1873 U U APPLICATIO S I FOR ATIO is most severe, and by including a few millivolts offset in the comparator that monitors the SW node. Despite these precautions, some combinations of inductor and layout parasitics can cause the LTC1873 ...

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U U APPLICATIO S I FOR ATIO FCB Pin In some circumstances desirable to control or disable discontinuous and Burst Mode operations. The FCB (Force Continuous Bar) pin allows the user to do this. When the FCB pin ...

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LTC1873 U U APPLICATIO S I FOR ATIO normal operation. The MAX comparator will act as usual, turning on QB until output is within range and then allowing the loop to resume normal operation. FAULT can also be pulled down ...

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U U APPLICATIO S I FOR ATIO that it all has to come out turn the MOSFET gate CC on, and when the MOSFET is turned back off, that charge all ends up at ground. In the ...

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LTC1873 U U APPLICATIO S I FOR ATIO maintain the input voltage until the input supply can make up the difference. Generally, a capacitor that meets the first two parameters will have far more capacitance than is required to keep ...

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U U APPLICATIO S I FOR ATIO from C (time point A). 50% of the way through, TG2 IN turns on and the total current is 13A (time point B). Shortly thereafter, TG1 turns off and the current drops to ...

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LTC1873 U U APPLICATIO S I FOR ATIO OUTPUT BYPASS CAPACITOR The output bypass capacitor has quite different require- ments from the input capacitor. The ripple current at the output of a buck regulator like the LTC1873 is much lower ...

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U U APPLICATIO S I FOR ATIO So far, the AC response of the loop is pretty well out of the user’s control. The modulator is a fundamental piece of the LTC1873 design, and the external L and C are ...

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LTC1873 U U APPLICATIO S I FOR ATIO – REF Figure 11a. Type 3 Amplifier Schematic Diagram GAIN (dB) –6dB/OCT +6dB/OCT GAIN 0 PHASE Figure 11b. Type 3 Amplifier ...

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... APPLICATIO S I FOR ATIO V(OUT) in degrees. Refer to your SPICE manual for details of how to generate this plot. *1873 modulator gain/phase © * 1999 Linear Technology *this file written to run with PSpice 8.0 *may require modifications for other SPICE simulators *MOSFETs rfet mod sw 0.02 ...

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LTC1873 U U APPLICATIO S I FOR ATIO CURRENT LIMIT PROGRAMMING Programming the current limit on the LTC1873 is straight- forward. The I pin sets the current limit by setting the MAX maximum allowable voltage drop across QB (the bottom ...

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U U APPLICATIO S I FOR ATIO with 20mV of hysteresis, allowing fairly precise control of the auxiliary voltage. If the LTC1873 is in discontinuous or Burst Mode operation and the auxiliary output voltage drops, the FCB pin will trip ...

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LTC1873 U U APPLICATIO S I FOR ATIO Maximizing Low Load Current Efficiency Low load current efficiency depends strongly on proper operation in discontinuous and Burst Mode operations ideally optimized system, discontinuous mode reduces conduction losses but not ...

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U U APPLICATIO S I FOR ATIO TRANSIENT RESPONSE Transient response is the other half of the regulation equation. The LTC1873 can keep the DC output voltage constant to within 1% when averaged over hundreds of cycles. Over just a ...

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LTC1873 U U APPLICATIO S I FOR ATIO Figure 15a. Capacitor Parasitics Affecting Transient Recovery OUT V ESR V CAP V OUT Selection section describes in detail how to design an optimized feedback loop, appropriate for most ...

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U U APPLICATIO S I FOR ATIO Implementing voltage positioning is as simple as creating an intentional resistance in the output path to generate the required voltage drop. This resistance can be a low value resistor, a length of PCB ...

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LTC1873 U U APPLICATIO S I FOR ATIO the actual load for the test, and switch it on and off while watching the output. If this isn’t convenient, a current step generator is needed. This generator needs to be able ...

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... FLASH SHALL NOT EXCEED 0.254mm (0.010") 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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... Synchronous Step-Down Controller with 5-Bit VID Control LTC1753 5-Bit Programmable Synchronous Switching Rregulator LTC1929 2-Phase, Synchronous High Efficiency Converter trademark of Linear Technology Corporation. SENSE Linear Technology Corporation 32 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 FAX: (408) 434-0507 www.linear-tech.com Single Output, 2-Phase, 25A VID Converter ...