SC480 SEMTECH [Semtech Corporation], SC480 Datasheet
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SC480
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SC480 Summary of contents
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... POWER MANAGEMENT Description The SC480 is a combination switching regulator and linear source/sink regulator intended for DDR1/2/3 memory systems. The purpose of the switching regulator is to generate the supply voltage, VDDQ, for the memory system pseudo-fi xed frequency constant on- time controller designed for high effi ciency, superior DC accuracy, and fast transient response ...
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... T = -40 TO +85C. AMB 25°C -40°C to 85°C Min Typ Max Min Max 1500 2500 800 1400 5 4.5 5.5 70 150 www.semtech.com SC480 Units °C/W °C °C °C kV Units μA μA V μA μA 5 μA μA ...
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... SC480 Units kΩ kΩ Ω μ kΩ mV Ω Ω mV μA μ ...
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... Min Typ Max Min Max 8 440 +16 +12 +20 5 0.1 -10 - 3.70 4.35 -12 -16 -8 +12 +8 +16 50 160 150 170 1.2 0.6 1.2 2.4 2.4 3.1 1.5 1 440 5.5 www.semtech.com SC480 Units clks (3) clks (3) % μ μA % μ μs ° MΩ MΩ μA clks (3) mV/μs ...
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... Min VDDQ Set for 2.5V (DDR1) VDDQ Set for 1.8V (DDR2 Rising DL Low High Low, BST - High, BST - 2.5V DH VTTS < REF VTTS > REF 5 SC480 = -40 TO +85C. AMB 25°C -40°C to 85°C Units Typ Max Min Max 0.3 VCCA - 0.7 30 0.8 3 ...
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... POWER MANAGEMENT POWER MANAGEMENT Shoot-Through Delay Timing Diagram LX DL tplhDL © 2006 Semtech Corp tplhDH 6 SC480 www.semtech.com ...
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... POWER MANAGEMENT Pin Confi guration SC480 MLP24 Pin Out PGND2 1 VTTS 2 VSSA 3 T TON 4 5 REF 6 VCCA Pin Description Pin # Pin Name Pin Function 1 PGND2 Power ground for VTT output. Connect to thermal pad and ground plane. 2 VTTS Sense pin for VTT. Connect to VTT at the load. ...
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... Notes: 1) EN/PSV = 1 = EN/PSV high or fl oating. 2) Typical discharge resistances: VTT = 0.25Ω. REF = 8Ω. 3) VDDQ is discharged via external series resistance which must be added to SC480 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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... Semtech Corp. VTTEN OTSD POR/SS DRVH FEDLY DRVL VTTPGD OTSD DSCHG POR/SS 1.5V REF CONTROL PWM -30% SD VSSA Figure 1 9 SC480 VTTIN DRVH NOVLP DRVL +12% -12% HI SHOOT THRU LO SENSE FAULTMON www.semtech.com VTT PGND2 VTTS BST DH LX VDDP DL PGND1 ILIM ...
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... POWER MANAGEMENT Application Information Application Information +5V Bias Supplies The SC480 requires an external +5V bias supply in addition 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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... Current Limit Circuit Current limiting of the SC480 can be accomplished in two 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. If PSAVE mode is enabled at very light loading, this leak can cause VDDQ to slowly rise and reach the OV threshold, causing a hard shutdown. To prevent this, the SC480 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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... Q2 FBK Figure 6 SC480 ESR Requirements The constant on-time control used in the SC480 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 SC480 is calculated to give a pseudo-fi xed frequency. Nevertheless, some frequency variation with line and load can be expected. This variation changes the output ripple voltage ...
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... ON_VBAT(MAX) = 274kHz and f = 251kHz SW_VBAT(MAX) we can calculate suitable values for ON t ON_VBAT V V (MIN) BAT(MIN) OUT 0.5 t ON_VBAT( (MAX) BAT(MAX) OUT 0 1.02μH and L = 1.30μH, VBAT(MIN) VBAT(MAX) SC480 MIN ) 9 OUT MAX ) The OUT OUT (MIN OUT ...
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... C with the top feedback resistor, R ripple at VFB is large enough. C than 100pF. The value of C TOP lows, where R is the bottom feedback resistor. Firstly BOT calculating the value of Z required: TOP 16 SC480 RIPPLE_VBA ( T MIN ) RIPPLE_VBA ( T MAX ...
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... OUT BAT ( MIN ) OUT RMS . Refer to manufacturer’s data sheets and RMS I RIPPLE_VBA ( T MIN I I VALLEY OUT 2 R 1.4 DS (ON) I 1.2 VALLEY 4mΩ, giving R = 5.62kΩ DS(ON) ILIM SC480 I OUT A RMS V BAT _ MIN ) A Ohms www.semtech.com ...
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... T is the junction temperature temperature the total SC480 device dissipation, The SC480 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 theground plane. Locate the current limit resistor at the chip with a kelvin connection to the phase node. 19 SC480 www.semtech.com ...
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... MBR0530 C4 1uF C8 0.1uF 1 PGND2 2 VTTS U1 3 VSSA SC480 4 TON R3 10R 5 REF 6 VCCA C15 1uF C16 0.1uF Figure 7 - Reference Design 20 SC480 Q1 C2 IRF7811 10uF/25V L1 1210 1.5uH Vishay IHLP-5050 Q2 VDDQ IRF7832 R1 5.62K + + C10* C9* 18 PGND1 220uF/12m 220uF/12m 17 PGND1 *Sanyo 4TPL220MC 16 ILIM 15 5V ...
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... SC480 1.8V Effi ciency vs. Output Current Continuous Conduction Mode VBAT = 10 VBAT = (A) OUT 2.5V Effi ciency vs. Output Current Continuous Conduction Mode VBAT = 10 VBAT = (A) OUT 1.5V Effi ciency vs. Output Current ...
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... 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 Load Transient Response 0A, Continuous Conduction Mode Load Transient Response SC480 www.semtech.com ...
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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 23 SC480 www.semtech.com ...
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... MAX MIN NOM MAX A .031 .035 .040 0.80 0.90 1.00 0.02 A1 .000 .001 .002 0.00 0.05 - (.008 (0.20) 0.25 b .007 .010 .012 0.18 0.30 D .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 bbb .004 0. www.semtech.com SC480 ...
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... 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 25 SC480 DIMENSIONS INCHES MILLIMETERS (.155) (3.95) 3.10 .122 .106 2.70 .106 2.70 .021 0.50 .010 0.25 .033 0.85 .189 4.80 www.semtech.com ...