sc2542 Semtech Corporation, sc2542 Datasheet
sc2542
Related parts for sc2542
sc2542 Summary of contents
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... POWER MANAGEMENT Description SC2542 is a high performance dual PWM controller designed to convert a widely ranged battery rail down to two independent output rails. The PWM operation of the two channels are 180 degrees out of phase which can greatly reduce the size and the cost of the input capaci- tors ...
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... SC2542 ± ...
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... º º SC2542 ...
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... & & SC2542 ...
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... Lead free product. This product is fully WEEE and RoHS FB2 FB2 compliant. ERROUT2 ERROUT2 MINSET2 MINSET2 SS2 SS2 ILIM2 ILIM2 BST2 BST2 DRVH2 DRVH2 PHASE2 PHASE2 DRVL2 DRVL2 PVCC PVCC 5 SC2542 ...
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... SC2542 ...
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... SC2542 ...
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... Semtech Corp. PWM S Q Minumin R Pulse Generator 0.65V + OUT R - Protect UVLO 0.75V Band 10V Band Gap 1 LDO Gap 2 0.75V 8 SC2542 PVCC Protect 1 PHASE1 PVCC Protect 1 Skip Mode dector VCC 10u A - OCP OUT + FB1 + OVP OUT - 0.89V 0.675V + FB1 - OUT ...
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... Power Good Figure 1. The functional block diagram. Skip Mode Operation When the RMIN pin is left open, the SC2542 operates as a synchronous PWM (SPWM) controller with the bot- tom MOSFET ON whenever the top MOSFET is OFF. Fig- ure 2 shows the typical SPWM waveforms. ...
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... When the load current falls from CCM to DCM, the duty cycle of DRVH (output of PWM comparator) will shrink. The programmed minimum pulse width of SC2542 with the DRVH signal to get the TG (top side MOSFET gate driver) pulse output. The TG output will maintain at least the programmed minimum pulse width. ...
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... Figure 6. Typical waveforms of SKIP mode. Frequency Setting The frequency of the SC2542 is user- programmable. The oscillator of SC2542 can be programmed with an external resistor from the Rosc pin to ground. The step- down controller is capable of operating up to 300KHz. The relationship between oscillation frequency versus oscillation resistor is shown in Figure 7. ...
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... DRVH/DRVL signals stop pulsing. The output volt- age ramps down at a rate determined by the load condi- tion. The SC2542 can also be shutdown by pulling down di- rectly on the SS pin. The designer needs to consider the slope of the SS pin voltage and choose a suitable pull down resistor to prevent the output from undershooting ...
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... In skip mode operation, the top FET driver always sends out a pulse which is wider than the DCM pulse to keep the load in regulation. This forces the SC2542 to oper- ate in skip mode and improves the light load efficiency. To set minimum pulse, one can use a simple formula: ...
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... Output capacitor (Co) type and value 3) Input capacitor (Cin) type and value 4) Power MOSFETs 5) Current sensing and limiting circuit Voltage sensing circuit Vo 7) Loop compensation network Rtop The following step-down converter specifications are needed: 14 SC2542 to 30k Then the bottom resistor BOT TOP ...
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... Maximum output current limit: Io,max Output (load) current transient slew rate: dIo/dt (A/s) Circuit efficiency: Inductor (L) and Ripple Current Both step-down controllers in the SC2542 operate in synchronous continuous-conduction mode (CCM) regardless except in light-load mode. The output inductor selection/design is based on the output DC and transient requirements. Both output current and ...
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... where R1a and C1a are the ESR and capacitance of elec- trolytic capacitors, and R1b and C1b are the ESR and capacitance of the ceramic capacitors, respectively (Fig- ure 13) C1a C1b R1a R1b Figure 14. Equivalent RC branch. 16 SC2542 ...
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... It is common practice that mul- tiple capacitors are placed in parallel to increase the ripple current handling capability. Sometimes meeting tight input voltage ripple specifica- tions may require the use of larger input capacitance. At full load, the peak-to-peak input voltage ripple due to 17 SC2542 ...
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... The two step-down channels of the SC2542 op- erate at 180 degrees from each other. If both step-down channels in the SC2542 are connected to the same in- put rail, the input RMS currents will be reduced. Ripple cancellation effect of interleaving allows the use of smaller input capacitors ...
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... The total power loss of MOSFET should be calculated and compared for high-line and low-line cases. The worst case is then used for thermal design. Bottom Switch The RMS current in bottom switch is given by: The conduction losses are then: 19 SC2542 + ( ...
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... Separate the power ground from the signal ground. In SC2542 design, use an isolated local ground plane for the controller and tie it to power grand. 2) Minimize the size of the high pulse current loop. Keep the top MOSFET, the bottom MOSFET and the input ca- pacitors within a small area with short and wide traces ...
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... R13 11 18 DRVH1 DRVH2 12 17 PHASE1 PHASE2 13 16 DRVL1 DRVL2 VCC 14 15 PGND PVCC C22 TH-PAD 1uF/16V R22 C28 2.2n/n.p. 21 SC2542 5VSBY 4.7uF 73.2K 10K PWGRD FB2 R7 41.2k C5 12nF 133k C9 1uF/16V 15K 1uF/16V 0 2.2 R15 VIN+ C10 C11 C12 Q2 4 ...
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... SC2542 ...
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... CH2: TG2 CH2: BG2 Shutdown by pulling down SS pin voltage CH1: TG CH2: BG CH3: Vss CH4: Vo Transient response ( CH1: TG CH2: BG CH3: Vss CH4 SC2542 CH1: TG1 CH2: BG1 CH2: TG2 CH2: BG2 CH1: Vi CH2: Vcc CH3: Vss CH4: Vo CH1: Vo CH4: Io www.semtech.com ...
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... Operating frequency vs. Rosc V in= 16V RILIM vs. OCP (Vin = 12V skip m ode Synchroniz 10000 4.5 24 SC2542 OHM www.semtech.com 9 ...
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... Dead time vs. Ta (Vin = 16V, DH falling to DL rising) 100 100 120 -40 25 SC2542 n(V) - 100 Temp. (Degree C) - 100 Ta (Degree C) www.semtech.com 120 ...
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... REFERENCE JEDEC STD MO-153, VARIATION AET. 2005 Semtech Corp e bxN bbb C A GAGE PLANE BOTTOM VIEW -A- AND - DETERMINED AT DATUM PLANE 26 SC2542 DIMENSIONS INCHES MILLIMETERS DIM MIN NOM MAX MIN NOM MAX - - - - A .047 1.20 A1 .000 - .006 0. ...
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... COMPANY'S MANUFACTURING GUIDELINES ARE MET. Contact Information Phone: (805)498-2111 FAX (805)498-3804 2005 Semtech Corp. F DIM INCHES (.222 .224 .161 H .126 P .026 Y X .016 Y .061 Z .283 Semtech Corporation Power Management Products Division 200 Flynn Road, Camarillo, CA 93012 27 SC2542 DIMENSIONS MILLIMETERS (5.65) 5.70 4.10 3.20 0.65 0.40 1.55 7.20 www.semtech.com ...