SC410 SEMTECH [Semtech Corporation], SC410 Datasheet
SC410
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SC410 Summary of contents
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... October 26, 2010 3A EcoSpeed with LDO and Ultrasonic Power Save Description The SC410 is an integrated, synchronous 3A EcoSpeed step-down regulator. It incorporates Semtech’s advanced, patented adaptive on-time architecture to achieve best- in-class dynamic performance using point-of-load appli- cations. The input voltage range is 5.5V to 24V with a programmable output voltage from 0 ...
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... Date code xxxx = Lot number Ordering Information Device SC410MLTRT SC410EVB 10 LDO Notes: (1) Available in tape and reel only. A reel contains 3,000 devices. (2) Lead-free packaging only. Device is WEEE and RoHS compliant AGND 9 and halogen-free. 8 TON SC410 Package (1)(2) MLPD- Evaluation Board 2 ...
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... J Conditions Programmable with EN pin after 2 switching cycles Rising UVLO 0A, f =25kHz (1) OUT SW See R Calculation TON during Ultrasonic PSAVE FB= SC410 (2) (°C Units Min Typ Max 1 0 μA 2.5 mA 0.7425 0.75 0.7575 ...
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... FB with Respect to REF FB with Respect to REF OT Latched Min Typ Max = 200kΩ 0.9 1 1.1 100 320 850 -10 0 +10 120 120 110 5 145 1.5 0.8 -10 10 SC410 Units μ μ REF ms μs μA Ω %V REF %V REF %V REF μs ° μA 4 ...
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... Low Side Short circuit protection 12V, V <80 LDO fi nal V value LDO Operating current limit 12V, V > 80 LDO fi nal V value LDO From 100mA IN LDO LDO SC410 Units Min Typ Max 25 Ω 2.4 3 μA 215 mΩ 110 LDO 35 mA 100 1 ...
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... R C BOT 10kΩ TOP 10nF R TOP 34kΩ Note: (1) Ceramic capacitors LDO LDO1 LDO2 R 1μF 0.1μF EN 10nF R TON 90.9kΩ (1) (1) OUT2 OUT3 OUT1 22µF 22µF 22µF R8 0Ω Position as close possible SC410 V OUT 3A max. (1) 6 ...
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... C NP TOP R TOP R BOT 10kΩ 34kΩ Notes: (1) Ceramic capacitor ( 2) Capacitor must provide ESR for user application V LDO LDO1 LDO2 R 0.1μF 1μF 10nF R TON 90.9kΩ OUT2 R8 0Ω Position as close possible SC410 EN V OUT 3A max. 7 ...
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... IN -1 12V IN 0.0 -2.4 1.0 10.0 0 0.20 0.18 0.15 0.13 0.10 0.08 0.05 0.03 0.00 2.0 2.5 3.0 0 OUT 1.8 1.2 0.6 0 -0.6 -1.2 -1.8 -2 3.3V 5V 90.9kΩ. OUT LDO TON Load Regulation V = 18V V = 24V 12V IN 0.1 1 OUT DC Switching Ripple V = 18V 24V 12V IN 0.5 1.0 1.5 2 OUT DC Line Regulation = 1. Input Voltage (V) SC410 10.0 2.5 3 ...
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... Time (400μs/div) = 12V 2.2μH (DCR = 35mΩ), C = 66μ OUT (20mV/div) (10V/div) (5V/div) (5V/div) (1V/div) (10V/div) (5V/div) (2V/div) (200mV/div) (10V/div) SC410 = 3.3V 5V 90.9kΩ. OUT LDO TON Power Save OUT Time (10μs/div) Shutdown I = 1.5A OUT Time (40μs/div) ...
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... Output for the internal LDO and internal connection to the bias node — Decoupling capacitors are required 10 LDO to AGND and PGND regardless of the use of the LDO for external loads. Thermal pad for heatsinking purposes. (Not connected internally) Connect to AGND plane using multiple PAD vias. SC410 10 ...
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... Block Diagram 9 AGND Reference Soft Start Comparator TON 8 PGOOD Control and Status LX Gate Drive On-Time Control Generator Zero Cross Detector V IN Valley Current Limit 5V LDO LDO 10 LDO BST 1 LDO LDO R ILIM ILIM SC410 2 VIN PGND 11 ...
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... The SC410 can operate with a wide input voltage ranging from 5.5V to 24V. The internal LDO generates a fixed 5V output that provides power for the bias of the SC410. The LDO can also provide additional power to an external load. Psuedo-fi xed Frequency Adaptive On-time Control The PWM control method used by the SC410 is pseudo- fi xed frequency, adaptive on-time, as shown in Figure 1 ...
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... The EN input is used to enable or disable the switching regulator. When EN is low (grounded), the switching regu- lator and LDO are disabled and the SC410 is in its lowest power state. When disabled, the output power switches are tri-stated. When EN is higher than 0.8V, the internal IN LDO will be activated ...
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... FB threshold. FB Figure 4 — Continuous Mode Operation Ultrasonic Power Save Operation The SC410 provides ultrasonic power save operation at light loads, with the minimum operating frequency fi xed at 22kHz. This is accomplished using an internal timer that monitors the time between consecutive high-side gate pulses. If the time exceeds 40μ ...
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... This method regulates the inductor valley current at the level shown by ILIM in Figure 7. Time Figure 7 — Valley Current Limit V discharges via inductor In the SC410, the valley current limit is set to 3A. This results OUT and low-side MOSFET in a peak inductor current of 3A plus the peak-to-peak Normal V ripple OUT ripple current ...
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... FETs until V 4.0V. An internal POR (Power-On Reset) occurs when V exceeds 4.0V, which resets the fault latch and soft start counter to begin the soft start cycle. The SC410 then begins a soft start cycle. The PWM will shut off if V below 3.7V. ...
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... RIPPLE is assumed TOL = 2.705 RIPPLE_MAX TOL = 4.353 RIPPLE_PEAK OUT TON OUT ON _ VINMIN V INMIN ( OUT RIPPLE _ VINMIN SC410 values that corre- H conditions is also 10 ns 611 ns 612 ...
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... LPK MAX TOL OUT LPK OUT 353 353 432 much smaller in this example, 33μF com- OUT SC410 . OUT LOAD LOAD ...
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... Figure 10. In this network R generate an in-phase ripple voltage comparable to the ripple seen on higher ESR capacitors. C capacitor used to AC couple the generated ripple onto the FB pin. 3 MIN OUT sw and C filter the LX switching waveform coupling C SC410 19 ...
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... L L tions it trips when the feedback pin is 750mV, The on-time pulse from the SC410 in the design example is calculated to give a pseudo-fi xed frequency of 500kHz. Some frequency variation with line and load is expected. This variation changes the output ripple voltage. Because adaptive on-time converters regulate to the valley of the output ripple, ½ ...
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... V as losses increase). The on-time is essen- IN tially constant for a given V and V OUT off set the losses the off -time will tend to reduce slightly as load increases. The net eff ect is that switching frequency increases slightly with increasing load. IN combination SC410 21 ...
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... Applications Information (continued) PCB Layout Guidelines The optimum layout for the SC410 is shown in Figure 11. This layout shows an integrated FET buck regulator with a maximum current of 3A. The total PCB area is approxi- mately 19.1mm x 11.3mm. Critical Layout Guidelines The following critical layout guidelines must be followed to ensure proper performance of the device. • ...
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... The current loops between the input capacitors, the IC, the inductor, and the output capacitors must be as close as possible to each other to reduce IR drop across copper planes and traces. • All bypass and output capacitors must be con- nected as close as possible to their respective pin on the IC. SC410 23 ...
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... D/2 DIMENSIONS INCHES MILLIMETERS MIN NOM MAX MIN NOM MAX - - .031 .039 0.80 1. .000 .002 0.00 0. (.008) (0.20) .007 .009 .011 0.18 0.23 0.30 .114 .118 .122 2.90 3.00 3.10 .074 .079 .083 1.87 2.02 2.12 .114 .118 .122 2.90 3.00 3.10 .042 .048 .052 1.06 1.21 1.31 .020 BSC 0.50 BSC .012 .016 .020 0.30 0.40 0. .003 0.08 .004 0.10 SC410 24 ...
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... THERMAL VIAS IN THE LAND PATTERN OF THE EXPOSED PAD SHALL BE CONNECTED TO A SYSTEM GROUND PLANE. FAILURE MAY COMPROMISE THE THERMAL AND/OR FUNCTIONAL PERFORMANCE OF THE DEVICE. DIM INCHES (.114 .083 H .055 .087 P .020 Y X .012 Y .031 Z .146 P DIMENSIONS MILLIMETERS (2.90) 2.10 1.40 2.20 0.50 0.30 0.80 3.70 SC410 25 ...
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... Notice: All referenced brands, product names, service names and trademarks are the property of their respective owners. Contact Information Semtech Corporation Power Management Products Division 200 Flynn Road, Camarillo, CA 93012 Phone: (805) 498-2111 Fax: (805) 498-3804 www.semtech.com SC410 26 ...