SC488 Semtech Corporation, SC488 Datasheet
SC488
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SC488 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 pseudo-fi xed frequency constant on-time controller designed for high effi ...
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... PKG V 2 ESD = 1MΩ -40 TO +85C. TON AMB 25°C -40°C to 85°C Min Typ Max Min 1500 800 5 4 www.semtech.com SC488 Units °C/W °C °C °C kV Units Max 2500 μA 1400 μA 5.5 V 150 μ ...
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... SC488 Units Max 552 ns 318 550 ns kΩ Ω 1.0 μ kΩ 918 mV Ω +40 mV 1.0 μA 11 μ 120 mV ...
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... VDDQ Set for 1.8V (DDR2) 4 25°C -40°C to 85°C Min Typ Max Min 8 440 +16 +12 5 -10 - 3.70 -12 -16 + 160 150 1.2 2.4 3.1 1.5 1.0 -1 440 5.5 0.3 VCCA - 0.7 www.semtech.com SC488 Units Max clks (3) clks (3) +20 % μs 0 μ μs 4. +16 % μs 170 °C 1.2 V 0.6 2 MΩ +1 μA clks (3) mV/μ ...
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... Rising DL Low High Low, BST - High, BST - 2.5V DH VTTS < REF VTTS > REF DH DL tplhDL 5 25°C -40°C to 85°C Min Typ Max Min 30 0.8 3 1.3 0.25 0.32 2.8 tplhDH www.semtech.com SC488 Units Max ns Ω A Ω A Ω Ω A Ω Ω A ...
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... NMOS output and requires an external pull-up resistor. © 2006 Semtech Corp. Ordering Information 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 17 ILIM 16 T VDDP 15 14 VDDP 13 PGD 6 (2) Device Package SC488MLTRT MLPQ-24 www.semtech.com SC488 (1) ...
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... Notes: 1) EN/PSV = 1 = EN/PSV high or fl oating. 2) Typical discharge resistances: VTT = 0.32Ω. REF = 8Ω. 3) VDDQ is discharged via external series resistance which must be added to SC488 internal discharge resistance to calculate discharge times. This is separate from any external load on VDDQ. FB Confi guration Table The FB pin can be confi gured for fi xed or adjustable output voltage as shown. ...
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... POR/SS FEDLY VTTRUN VTTPGD OTSD TON/ TOFF DSCHG POR/SS 1.5V REF CONTROL 1.5V PWM -10% -30% SD +16% VSSA Figure 1 8 VTTIN DRVH NOVLP DRVL DRVH +12% DRVL -12% HI SHOOT THRU DL LO SENSE FAULTMON SC488 VTT PGND2 VTTS BST DH LX VDDP DL PGND1 ILIM PGD www.semtech.com ...
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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 minimize crosstalk, the controller has seven supply pins: VDDP (2 pins), PGND1 (2 pins), PGND2, VCCA and AGND ...
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... V out ⎝ Current Limit Circuit Current limiting of the SC488 can be accomplished in two www.DataSheet4U.com ways. The on-state resistance of the low-side MOSFETs can be used as the current sensing element sense resistor in the low-side source can be used if greater ac- curacy is desired. RDSON sensing is more effi cient and less expensive ...
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... VDDQ to slowly rise and reach the OV threshold, causing a hard shutdown. To prevent this, the SC488 uses Smart OVP to prevent this. When VDDQ exceeds 8% above nominal, DL drives high to turn on the low-side MOSFET, which starts to draw current from VDDQ via the inductor ...
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... ESR should be increased. SC488 ESR Requirements The constant on-time control used in the SC488 regulates the ripple voltage at the output capacitor. This signal consists of a term generated by the output ESR of the capacitor and a term based on the increase in voltage across the capacitor due to charging and discharging during the switching cycle ...
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... The on-time pulse in the SC488 is calculated to give a pseudo-fi xed frequency. Nevertheless, some frequency variation with line and load can be expected. This varia- tion changes the output ripple voltage ...
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... SW_VBAT(MIN) SW_VBAT(MAX) we can calculate suitable values for ON t ON_VBAT VBAT (MIN) BAT(MIN) OUT VBAT (MAX) BAT(MAX) OUT L = 1.02μH and L = 1.30μH, VBAT(MIN) VBAT(MAX) SC488 V OUT BAT ( MIN ) V OUT BAT ( MAX ) The OUT ...
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... R I RIPPLE_VBA ( T MIN ) ESR RIPPLE_VBA R I RIPPLE_VBA ( T MAX ) ESR RIPPLE_VBA = 20mV and V P-P RIPPLE_VBAT(MIN) at minimum V P-P . Note that the voltage ripple at P-P RIPPLE_VBAT(MIN) - whether internal or ex- P-P SC488 Ohms ( T MAX ) MIN ) MAX ) P = 26mV P-P , should FB , and worst case BAT as seen at www.semtech.com ...
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... C L OUT(MIN) 2 POSLIM V TR OUT_ST_POS term. In this case I fi nal . = 392μ RMS ) OUT BAT ( MIN ) OUT = 4.17A RMS . Refer to manufacturer’s data sheets and RMS SC488 ( T MAX ) set for 5A. fi nal I OUT A RMS V BAT _ MIN www.semtech.com ...
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... T is the junction temperature temperature the total SC488 device dissipation. The SC488 device dissipation can be determined using VCCA • ICCA + VDDP • IDDP + VTT • |ITT| The fi rst two terms are losses for the analog and gate drive circuits and generally do not present a thermal problem ...
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... BST is also a noisy node and should be kept as short as possible. 4. Connect PGND1 pins on the chip directly to the VDDP decoupling capacitor and then drop vias directly to the ground plane. Locate the current limit resistor (if used) at the chip with a kelvin connection to the phase node. 18 SC488 www.semtech.com ...
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... C10* C9* 18 PGND1 220uF/12m 220uF/12m 17 PGND1 *Sany o 4TPL220MC 16 ILIM 15 VDDP C12 14 1uF VDDP R4 13 10K PGD PAD PAD EN/PSV VTT_EN 1.8V fixed: connect to 5V 2.5V fixed: connect to VSSA Adjustable 1.5V-3.0V: connect to divider netw ork SC488 VBAT C3 10uF/25V 1210 VDDQ + C11 0.1uF 5V PGOOD www.semtech.com ...
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... SC488 1.8V Effi ciency vs. Output Current Continuous Conduction Mode VBAT = 10 VBAT = IOUT (A) 2.5V Effi ciency vs. Output Current Continuous Conduction Mode VBAT = 10 VBAT = IOUT (A) 1.5V Effi ciency vs. Output Current ...
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... Load Transient Response 5A, Psave Mode www.DataSheet4U.com Load Transient Response 0A, Psave Mode Load Transient Response 10A © 2006 Semtech Corp. Load Transient Response 5A, Continuous Conduction Mode Load Transient Response 0A, Continuous Conduction Mode Load Transient Response SC488 www.semtech.com ...
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... POWER MANAGEMENT Typical Characteristics (Cont.) VTT Load Transient Response, 1A Sink/Source, Psave Mode www.DataSheet4U.com 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 SC488 www.semtech.com ...
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... A1 .000 .001 .002 0.00 0. (.008) (0.20) A2 0.25 b .007 .010 .012 0.18 0. .151 .157 .163 3.85 4.00 4.15 D1 .100 .106 .110 2.55 2.70 2.80 E .151 .157 .163 3.85 4.00 4.15 E1 .100 .106 .110 2.55 2.70 2.80 e .020 BSC 0.50 BSC L .011 .016 .020 0.30 0.40 0. aaa .004 0.10 A2 bbb .004 0.10 SEATING PLANE E/2 bbb SC488 www.semtech.com ...
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... COMPANY'S MANUFACTURING GUIDELINES ARE MET. Contact Information © 2006 Semtech Corp. K DIM Semtech Corporation Power Management Products Division 200 Flynn Road, Camarillo, CA 93012 Phone: (805) 498-2111 Fax: (805) 498-3804 www.semtech.com 24 DIMENSIONS INCHES MILLIMETERS (.155) (3.95 .122 3.10 H .106 2.70 K .106 2.70 P .021 0.50 X .010 0.25 Y .033 0.85 Z .189 4.80 www.semtech.com SC488 ...