SC1404 Semtech Corporation, SC1404 Datasheet
SC1404
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SC1404 Summary of contents
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... The SC1404 is a multiple-output power supply controller designed to power battery operated systems. The SC1404 provides syn- chronous rectified buck converter control for two power supplies. An efficiency of 95% can be achieved. The SC1404 uses Semtech’s proprietary Virtual Current Sense with external error amplifier compensation to achieve enhanced stability and DC accuracy over a wide range of output filter compo- nents while maintaining fixed frequency operation ...
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... < < SC1404 PRELIMINARY ...
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... A < I < µ < I < SC1404 =-40 to 85° ...
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... SC1404 PRELIMINARY =-40 to 85° ...
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... < SC1404 =-40 to 85° ...
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... SC1404 PRELIMINARY ...
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... PS 2.5m V POL POL PWM PWM MODULATOR MODULATOR OV FAULT +10% -25% UV FAULT DELAY V+ CURRENT CSL3 RAMP 2.5V CSL5 REF 3 POW ER-ON SEQUENCE LOGIC VL 2 RUN/ON3 7 SC1404 200m A VDD 12OUT + 4.7µ REG VL VIN BST5 HS DH5 T1 LX5 VL 1:3 LS DL5 PGND 50mV 7.5m V 2.5m V CSH5 CSL5 COMP5 TIMER ...
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... Only available in tape and reel packaging. A reel contains 2500 devices SC1404 PRELIMINARY ° ...
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... MOSFET has dropped low before the high-side MOSFET is turned on. 2003 Semtech Corp. Under light load conditions when the PSAVE pin is low, the SC1404 operates as a hysteretic controller in discontinuous conduction mode to reduce switching frequency and switching bias current. The switching frequency then is determined by the hysteretic trip voltage set around the reference ...
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... Power up Controls and Soft Start The user has control of the SC1404 RESET# by setting the SEQ, ON3 and ON5 pins as described in the following table. At startup, the RESET# pin is held low for 32K switching cycles. Another timer is used to enable the undervoltage protection. The undervoltage protection circuitry is enabled after 6144 switching cycles, at which time the SMPS should be in regulation ...
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... W Applications Information Reference Circuit Design Introduction The SC1404 is a versatile dual switching regulator with fixed 5V and 3.3V outputs . In addition, there is an on-chip 5V linear regulator capable of supplying 50mA output current and a 12V linear regulator able to provide 200mA. The SC1404 is designed for notebook applications but has is suited to applications where high efficiency, small package, and low cost are required ...
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... SWITCHING I G where Crss is the reverse transfer capacitance of the MOSFET equal to 200pF for STS12NF30L the gate driver current equal to 1A for SC1404. And Vin_nom = 15V 300KHz. The switching loss is calculated to 81mW. And the gate loss is given by ...
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... To compensate for the SC1404 is easy since the output of error amplifier COMP pin is available for external compensation. A traditional pole-zero- pole compensation is not necessary in the design using SC1404. ...
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... Simulated overall gain & phase responses (up to 100KHz) is plot- ted below -20 -40 -60 1.00E+05 -80 1.00E+02 1.00E+03 180 160 140 120 100 -20 1.00E+02 1.00E+03 1.00E+05 14 SC1404 PRELIMINARY 1.00E+04 1.00E+05 Frequency (Hz) 1.00E+04 1.00E+05 f (Hz) 1.00E+04 1.00E+05 f (Hz) www.semtech.com ...
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... POWER MANAGEMENT Applications Information Measured overall gain & phase response of the single-pole com- pensation using SC1404 is plotted below -10 -45 -80 1.00E+02 1.00E+03 f (Hz) 180 160 140 120 100 -20 1.00E+02 1.00E+03 f (Hz) Table I. Recommended compensation cap for different output capacitance ...
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... The SC1404 implements this by changing the phase relationship between the converter depending on the input 0 voltage ...
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... Schottky diode with a forward current of 0.5A is sufficient for this design. Operation below 6V input The SC1404 will operate below 6V input voltage with careful design, but there are limitations. The first limitation is the maximum available duty cycle from the SC1404, which limits the obtainable output voltage ...
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... SHDN# or ON5 pin should be enough to delay turn-on until the input reaches 6V. 3. For slow dV/dt on the input (10’s of msec), the SC1404 should be held off until the input reaches 6V. This can be done using a comparator or external logic to hold the SHDN# or ON5 pin low until the input reaches 6V ...
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... DVMs monitoring ON5 and the output under test. Oscilloscope probe connected to Phase Node of the output under test (not strictly required). Set Lab Supply 2 to provide 10V at the SC1404 input. The phase node of the output being tested should show some switching ac- tivity. The ON5 pin should be above 4V. ...
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... Before starting to layout the PCB, a careful layout strategy is strongly recom- mended. See the PCB layout in the SC1404 Evaluation Kit manual for example. In most applications, we recommend to use FR4 with 4 or more layers and at least 2 oz copper (for output current up to 6A) ...
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... POWER MANAGEMENT Typical Characteristics 3.3V Efficiency 6V 100 0.01 0.1 Load Current (A) 5V Efficiency 6V 100 0.01 0.1 Load Current (A) 2003 Semtech Corp. 10V 19V 1 10 10V 19V SC1404 www.semtech.com ...
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... DL3 VDD 24 5 BST3 12OUT 1 2 BST3R 25 4 PHASE3 COMP3 26 3 DH3 CSL3 27 2 RUN/ON3 CSH3 IRF7413 30BQ015 NEG 2 22 SC1404 PRELIMINARY www.semtech.com ...
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... SC1404 ...
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... SC1404 PRELIMINARY ...
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... POWER MANAGEMENT Evaluation Board Gerber Plots Inner1 Inner1 Inner1 Inner1 Inner1 2003 Semtech Corp. Inner2 Inner2 Inner2 Inner2 Inner2 Bottom Bottom Bottom Bottom Bottom 25 SC1404 www.semtech.com ...
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... POWER MANAGEMENT Outline Drawing - SSOP-28 2003 Semtech Corp. 26 SC1404 PRELIMINARY www.semtech.com ...
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... POWER MANAGEMENT Outline Drawing - TSSOP-28 Land Pattern - TSSOP-28 Contact Information Phone: (805)498-2111 FAX (805)498-3804 2003 Semtech Corp. Semtech Corporation Power Management Products Division 200 Flynn Road, Camarillo, CA 93012 27 SC1404 www.semtech.com ...