sc488mltrt Semtech Corporation, sc488mltrt Datasheet
sc488mltrt
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sc488mltrt Summary of contents
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POWER MANAGEMENT Description The SC488 is a combination switching regulator and lin- ear source/sink regulator intended for DDR1/2 memory systems. The purpose of the switching regulator is to gen- erate the supply voltage, VDDQ, for the memory system ...
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POWER MANAGEMENT Absolute Maximum Ratings Exceeding the specifi cations below may result in permanent damage to the device or device malfunction. Operation outside of the parameters specifi the Electrical Characteristics section is not implied. Exposure to absolute maximum ...
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POWER MANAGEMENT Electrical Characteristics (Cont.) Parameter VDDQ Controller FB Error Comparator With Adjustable Resistor Divider Threshold (1) VDDQS Regulation Threshold On-Time Minimum Off-Time VDDQS Input Resistance VDDQS Shutdown Discharge Resistance FB Leakage Current VDDQ Smart Psave Threshold VTT Controller REF ...
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POWER MANAGEMENT Electrical Characteristics (Cont.) Parameter VDDQ Fault Protection (continued) Under-Voltage Fault Delay Under-Voltage Blank Time Output Over-Voltage Fault With Respect to FB Regulation Point Over-Voltage Fault Delay FB Above Over-Voltage Threshold PGD Low Output Voltage PGD Leakage Current PGD ...
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POWER MANAGEMENT Electrical Characteristics (Cont.) Parameter Gate Drives Shoot-Thru Protection Delay (4)(7) DL Pull-Down Resistance DL Sink Current DL Pull-Up Resistance DL Source Current DH Pull-Down Resistance DH Pull-Up Resistance (8) DH Sink/Source Current VTT Pull-Up Resistance VTT Pull-Down Resistance ...
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... PGD pin is an open drain NMOS output and requires an external pull-up resistor. © 2006 Semtech Corp. Ordering Information Device SC488MLTRT Notes: 1) Only available in tape and reel packaging. A reel contains 3000 devices. PGND1 18 2) This product is fully WEEE and RoHS compliant. PGND1 ...
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POWER MANAGEMENT Pin Description (Cont.) 14,15 VDDP +5V supply voltage input for the VDDQ gate drivers. Current limit input pin. Connect to drain of low-side MOSFET for RDS(on) sensing or the source 16 ILIM for resistor sensing through a threshold ...
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POWER MANAGEMENT Block Diagram VCCA VDDQS +12% -12% REF DSCHG VCCA VTTRUN EN/ PSV TON TON/ TOFF VDDQS VDDQS DSCHG -10% +16% VMON -30% 1.5V FB -10 +16% © 2006 Semtech Corp. VTTEN OTSD POR/SS DRVH FEDLY DRVL ...
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POWER MANAGEMENT Application Information Application Information +5V Bias Supplies The SC488 requires an external +5V bias supply in addi- tion to the battery. If stand-alone capability is required, the +5V supply can be generated with an external linear regulator. To ...
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POWER MANAGEMENT Application Information Referencing Figure 2, the equation for setting the output voltage is: ⎛ ⎜ out ⎝ R3 Current Limit Circuit Current limiting of the SC488 can be accomplished in two ways. The on-state ...
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POWER MANAGEMENT Application Information (Cont.) Power Good Output The VDDQ controller has a power good (PGD) output. Power good is an open-drain output and requires a pull-up resistor. When the output voltage is +16%/-10% from its nominal voltage, PGD gets ...
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POWER MANAGEMENT Application Information (Cont.) Switching Frequency Switching frequency determines the trade-off between size and effi ciency. Higher frequency increases switch- ing losses in the MOSFETs, since losses are a function of F*VIN2. Knowing the maximum input voltage and budget ...
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POWER MANAGEMENT Application Information (Cont.) Dropout Performance The output voltage adjust range for continuous-conduction operation is limited by the fi xed 400nS (typical) Minimum Off-time One-shot. For best dropout performance, use the slowest on-time setting of 200KHz. When working with ...
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POWER MANAGEMENT Application Information (Cont.) For stability, place a 10Ω/1μF series combination from REF to VSSA. If REF load capacitance exceeds 1μF, place at least 10Ω’s in series with the load capacitance to prevent instability possible to use ...
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POWER MANAGEMENT Application Information (Cont.) We will select an inductor value of 1.5μH to reduce the ripple current, which can be calculated as follows RIPPLE_V BAT ( MIN ) BAT ( MIN ) OUT and ...
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POWER MANAGEMENT Application Information (Cont.) When using external feedback, and with VDDQ greater than 1.5V, a small capacitor can be used in parallel TOP with the top feedback resistor, R TOP ripple at VFB is large enough. C ...
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POWER MANAGEMENT Application Information (Cont.) Finally, we calculate the current limit resistor value. As de- scribed in the current limit section, the current limit looks at the “valley current”, which is the average output cur- rent minus half the ripple ...
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POWER MANAGEMENT Application Information (Cont.) feedback signal VTTS is critical. The trace from VTTS (pin 2) should be connected directly to the output capacitor that is farthest from VTT (pin24); route this signal away from noise sources such as the ...
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POWER MANAGEMENT Application Information (Cont.) VDDQ VTT 10uF 10uF 10uF 0805 0805 0805 R2 1MEG VBAT REF R5 10R 5V C13 C14 1uF 1nF VDDQ © 2006 Semtech Corp 0.1uF 5V MBR0530 C4 1uF C8 ...
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POWER MANAGEMENT Typical Characteristics 1.8V Effi ciency vs. Output Current Powersave Mode 100% VBAT = 10 90% 80% VBAT = 20 70% 60% 50 IOUT (A) 2.5V Effi ciency vs. Output Current Powersave Mode 100% VBAT ...
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POWER MANAGEMENT Typical Characteristics (Cont.) Load Transient Response 5A, Psave Mode Load Transient Response 0A, Psave Mode Load Transient Response 10A © 2006 Semtech Corp. Load Transient Response 5A, Continuous Conduction Mode ...
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POWER MANAGEMENT Typical Characteristics (Cont.) VTT Load Transient Response, 1A Sink/Source, Psave Mode Startup (PSV), EN/PSV Going High © 2006 Semtech Corp. VTT Load Transient Response, 1A Sink/Source, Continuous Conduction Mode Startup (PSV), EN/PSV Going Low, VDDQ = 5A 22 ...
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POWER MANAGEMENT Outline Drawing - MLPQ 24 (4x4mm) PIN 1 INDICATOR (LASER MARK) A aaa C NOTES: 1. CONTROLLING DIMENSIONS ARE IN MILLIMETERS (ANGLES IN DEGREES). COPLANARITY APPLIES TO THE EXPOSED PAD AS WELL AS THE TERMINALS. 2. © 2006 ...
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... COMPANY'S MANUFACTURING GUIDELINES ARE MET. Contact Information Phone: (805) 498-2111 Fax: (805) 498-3804 © 2006 Semtech Corp. K DIM Semtech Corporation Power Management Products Division 200 Flynn Road, Camarillo, CA 93012 www.semtech.com 24 SC488 DIMENSIONS INCHES MILLIMETERS (.155) (3.95) .122 3.10 .106 2.70 .106 2.70 ...