SC1404ITSTR Semtech, SC1404ITSTR Datasheet
SC1404ITSTR
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SC1404ITSTR Summary of contents
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... The SC1404 is a multiple-output power supply controller designed for battery operated systems. The SC1404 provides synchronous rectified buck converter control for two power supplies. An effi- ciency of 95% can be achieved. The SC1404 uses Semtech’s proprietary Virtual Current Sense technology along with external ...
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... Exceeding the specifications below may result in permanent damage to the device, or device malfunction. Operation outside of the parameters specified in the Electrical Characteristics section is not implied Electrical Characteristics Unless otherwise noted 15V, both PWMs on, SYNC = 0V, VL load = 0mA, REF load = 0mA, PSAVE# = 0V, T Typical values are +25°C. Circuit = Typical Application Circuit 2004 Semtech Corp < < SC1404 PRELIMINARY ± ...
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... POWER MANAGEMENT Electrical Characteristics Cont. Unless otherwise noted 15V, both PWMs on, SYNC = 0V, VL load = 0mA, REF load = 0mA, PSAVE# = 0V, T Typical values are +25°C. Circuit = Typical Application Circuit 2004 Semtech Corp < < < < µ A < I < µ < I < SC1404 =-40 to 85°C. ...
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... POWER MANAGEMENT Electrical Characteristics Cont. Unless otherwise noted 15V, both PWMs on, SYNC = 0V, VL load = 0mA, REF load = 0mA, PSAVE# = 0V, T Typical values are +25°C. Circuit = Typical Application Circuit 2004 Semtech Corp ° SC1404 PRELIMINARY =-40 to 85° www.semtech.com µ µ µ ° ...
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... Unless otherwise noted 15V, both PWMs on, SYNC = 0V, VL load = 0mA, REF load = 0mA, PSAVE# = 0V, T Typical values are +25°C. Circuit = Typical Application Circuit Notes: (1) This device is ESD sensitive. Use of standard ESD handling procedures required. (2) Applicable from 0 to +85°C. 2004 Semtech Corp ...
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... POWER MANAGEMENT Pin Descriptions Note: All logic level inputs and outputs are open collector TTL compatible. 2004 Semtech Corp SC1404 PRELIMINARY µ www.semtech.com ...
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... POWER MANAGEMENT Block Diagram 2004 Semtech Corp. 7 SC1404 www.semtech.com ...
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... POWER MANAGEMENT Pin Configuration Top View TSSOP-28/SSOP-28 Block Diagram 2004 Semtech Corp. Ordering Information Note (1) Only available in tape and reel packaging. A reel contains 2500 devices for TSSOP and 1000 devices V + for SSOP SC1404 PRELIMINARY ° www.semtech.com ...
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... The SC1404 operates in forced continuous conduction mode as a fixed frequency peak current mode controller with falling edge modulation. Current sense is done differently than in conventional peak current mode control. Semtech’s proprietary Virtual Current Sense emulates the necessary inductor current information for TM proper functioning of the IC ...
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... Holding the SHDN pin low disables the SC1404, reducing the V+ input current to less than 10uA. When SHDN is high, the part enters standby mode where the VL regulator and VREF are enabled. Turning on either SMPS will put the SC1404 in run mode. 2004 Semtech Corp ...
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... For the reference design, the Coiltronics DR127-6R8 is used. This is acceptable for the 3V output, which uses a simple inductor. The 5V inductor must have a 12V winding with a turns ratio of 2.2:1. For the 5V inductor, the TTI-8215 from Transpower Technologies is used, which has 5V inductance of 6.4uH. 2004 Semtech Corp ...
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... P θ the total device dissipation, and T resistance, which is 50°C/W for the IRf7413. The junction tem- perature rise is then: 2004 Semtech Corp. This is an acceptable temperature rise special heat sinking ∆I is required LOAD 2 Designing the Loop Vo Vin A good loop design is a combination of the power train and com- pensation design ...
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... Semtech Corp. 200 150 100 50 0 -50 -100 -150 -200 1.00E+02 1.00E+03 1.00E+05 Single-pole compensation is achieved using a 100pF capacitor from the COMP pin to ground. The simulated feedback gain & phase response (up to 100kHz) is plotted below. ...
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... Simulated overall gain & phase responses (up to 100kHz) is plot- ted below -20 -40 -60 -80 1.00E+02 1.00E+03 1.00E+04 f (Hz) 2004 Semtech Corp. 180 160 140 120 100 -20 1.00E+02 1.00E+05 Measured overall gain & phase response of the single-pole com- pensation using SC1404 is plotted below. ...
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... I3in D3 I5in D5 Iin Icap 2004 Semtech Corp. As the input voltage is reduced, the duty cycle of both converters increases. At input voltages less than 8.3V impossible to prevent overlap regardless of the phase between the converters. Overlap is seen in the following figure. I5in Iin ...
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... Schottky diode. The current rating of the Schottky diode can be determined by the following equation: 2004 Semtech Corp. IF_AVG cycle where 100nsec is the estimated time between the mosfet turn- off and the Schottky diode turn-on and ...
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... But the stray (leakage) inductance of the inductor resists rapid changes in winding current, and ultimately limits how much current can be drawn from 15V before the voltage falls. 2004 Semtech Corp. The following guidelines for 12V loading apply to the typical circuit, page 22. V ...
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... Semtech recommends the following circuit for measuring the ov- ervoltage trip point. D1 prevents the output voltage from damag- ing lab supply 1. R1 limits the amount of energy that can be cycled from the output to the input ...
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... This is important when the converter needs to handle high di/dt requirements. 2004 Semtech Corp. b. Current Sense. Minimize the length of current sense signal traces. Keep them less than 15mm. Kelvin connections should be used; try to keep the traces parallel to each other and route them close to each other as much as possible ...
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... POWER MANAGEMENT Evaluation Board Schematic NEG 2 2004 Semtech Corp. NEG SEQ CSH5 15 14 DH5 CSL5 16 13 PHASE5 COMP5 17 12 BST5 RESET 1 2 BST5R 18 11 DL5 PSAVE 19 10 PGND REF GND TIME/ON5 22 7 SHDN SYNC 23 6 DL3 VDD 24 5 BST3 12OUT 2 25 ...
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... POWER MANAGEMENT Evaluation Board Bill of Materials 2004 Semtech Corp SC1404 www.semtech.com ...
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... POWER MANAGEMENT Evaluation Board Bill of Materials Cont 2004 Semtech Corp SC1404 PRELIMINARY www.semtech.com ...
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... POWER MANAGEMENT Evaluation Board Gerber Plots Inner1 Inner1 Inner1 Inner1 Inner1 2004 Semtech Corp. Inner2 Inner2 Inner2 Inner2 Inner2 Bottom Bottom Bottom Bottom Bottom 23 SC1404 www.semtech.com ...
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... POWER MANAGEMENT Outline Drawing - TSSOP-28 Land Pattern - TSSOP-28 2004 Semtech Corp. 24 SC1404 PRELIMINARY www.semtech.com ...
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... Outline Drawing - SSOP-28 Land Pattern - SSOP-28 X (C) P NOTES: 1. THIS LAND PATTERN IS FOR REFERENCE PURPOSES ONLY. CONSULT YOUR MANUFACTURING GROUP TO ENSURE YOUR COMPANY'S MANUFACTURING GUIDELINES ARE MET. Contact Information Phone: (805)498-2111 FAX (805)498-3804 2004 Semtech Corp. DIMENSIONS DIM INCHES C .281 G .216 .026 X ...