MAX8550-MAX8551 MAXIM [Maxim Integrated Products], MAX8550-MAX8551 Datasheet
MAX8550-MAX8551
Related parts for MAX8550-MAX8551
MAX8550-MAX8551 Summary of contents
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... The MAX8550/MAX8551 allow flexible sequencing and standby power manage- ment using the SHDNA, SHDNB, and STBY inputs. Both the MAX8550 and MAX8551 are available in a small 5mm × 5mm, 28-pin thin QFN package. DDR I and DDR II Memory Power Supplies ...
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Integrated DDR Power-Supply Solutions for Desktops, Notebooks, and Graphic Cards ABSOLUTE MAXIMUM RATINGS V to GND .............................................................-0.3V to +30V VTTI to GND .........................................-0.3V to +6V DD, DD SHDNA, SHDNB, REFIN to GND..............................-0.3V to +6V SS, POK1, ...
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Integrated DDR Power-Supply Solutions for Desktops, Notebooks, and Graphic Cards ELECTRICAL CHARACTERISTICS (continued +15V SHDNA GND, PGND1 = PGND2 = LX = GND, TON = OPEN, V ...
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Integrated DDR Power-Supply Solutions for Desktops, Notebooks, and Graphic Cards ELECTRICAL CHARACTERISTICS (continued +15V SHDNA GND, PGND1 = PGND2 = LX = GND, TON = OPEN, V ...
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Integrated DDR Power-Supply Solutions for Desktops, Notebooks, and Graphic Cards ELECTRICAL CHARACTERISTICS (continued +15V SHDNA GND, PGND1 = PGND2 = LX = GND, TON = OPEN, V ...
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Integrated DDR Power-Supply Solutions for Desktops, Notebooks, and Graphic Cards = 2.5V, TON = GND, SKIP = 12V, V VIN OUT EFFICIENCY vs. LOAD CURRENT (TON = GND) 100 f = 600kHz ...
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... MAX8550/51 toc16 R = 10Ω, LOAD R = 20Ω VTT V OUT 1V/div VTT 1V/div SHDNA + SHDNB 5V/div POK1 5V/div = +25°C, unless otherwise noted.) LOAD TRANSIENT VTT (-3A TO +3A) MAX8550/51 toc12 I = 12A 15mA LOAD VTTR V OUT 50mV/div VTT 50mV/div VTTR 50mV/div I VTT 2A/div 0A 40µs/div ...
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... V IN 10V/div 2A/div SHORT CIRCUIT AND RECOVERY OF V DDQ MAX8550/51 toc19 UVP DISABLED, FOLDBACK CURRENT LIMIT V OUT 2V/div I LOAD 10A/div V IN 10V/div I IN 2A/div 400µs/div SHORT CIRCUIT OF VTT MAX8550/51 toc21 VTT 1V/div I VTT 5A/div 400µs/div ...
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... OVP/ OVP is also enabled. Connect the OVP/UVP pin to the following pins for the desired function: UVP OVP/UVP = AV (MAX8550) 2 OVP/UVP = OPEN (Enable OVP and discharge mode, disable UVP.) OVP/UVP = REF (Disable OVP and discharge mode, enable UVP.) OVP/UVP = GND (Disable OVP and discharge mode, disable UVP.) N.C. Do not connect ...
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... Power Ground for Buck Controller. Connect PGND1 externally to the underside of the exposed pad. 24 GND Analog Ground for Both Buck and LDO. Connect GND externally to the underside of the exposed pad. SKIP Pulse-Skipping Control Input. Connect to AV (MAX8550) enable pulse-skipping operation. 25 TP1 In the MAX8551, this pin is a test pin and must be connected to GND (pin 24). (MAX8551) Analog Supply Input for Both Buck and LDO ...
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... LX 20ms TIMER V = 1.8V OUT INTREF - 10 2.5V OUT FB DECODE +0.4V REFIN / 2 + 10% POWER-DOWN* VTT ILIM CURRENT LIMITS VTTR ILIM REFIN / 2 + 10% SS OFF TRIG MAX8550/ MAX8551 BST PGND ILIM SKIP (TP1 IN MAX8551 MUST BE CONNECTED TO GND) ZERO CROSSING LX OUT DISCHARGE N LOGIC AV DD ...
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... Bias Supply (V The MAX8550/MAX8551 require an external +5V bias supply in addition to the input voltage (V bias supply external to the IC improves the efficiency and eliminates the cost associated with the +5V linear regulator that would otherwise be needed to supply the PWM circuit and the gate drivers ...
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Integrated DDR Power-Supply Solutions for Desktops, Notebooks, and Graphic Cards 2) The inductor ripple-current operating point remains relatively constant, resulting in an easy design methodology and predictable output voltage ripple. The on-time one-shot has good accuracy at the operat- ing ...
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... Current-Limit Buck Regulator (ILIM) Valley Current Limit The current-limit circuit for the buck regulator portion of the MAX8550/MAX8551 employs a unique “valley” cur- rent-sensing algorithm that senses the voltage drop across LX and PGND1 and uses the on-resistance of the rectifying MOSFET (Q2 in the Typical Applications Circuit, Figure 8) as the current-sensing element ...
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... The buck regulator’s internal soft-start allows a gradual I LOAD increase of the current-limit level during startup to reduce the input surge currents. The MAX8550/ MAX8551 divide the soft-start period into five phases. During the first phase, the controller limits the current I LIMIT limit to only 20% of the full current limit. If the output does not reach regulation within 425µ ...
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... SHDNA and SHDNB are pulled low UVP is enabled (OVP/UVP = AV DD 70% of its regulation set point, the MAX8550 dis- charges the buck regulator output (through the OUT input) through an internal 10Ω switch to ground. While the output is discharging forced low and the PWM controller is disabled but the reference remains Table 2 ...
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... Overvoltage Protection (OVP) When the output voltage rises above 116% of the nomi- nal regulation voltage (MAX8550 only) and OVP is enabled (OVP/UVP = AV or open), the OVP circuit DD sets the fault latch, shuts down the PWM controller, and immediately pulls DH low and forces DL high ...
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... AV connect FB directly to OUT for a fixed 0.7V output. ) and maxi- IN Setting the Buck Regulator Output (V The buck-regulator output voltage can be adjusted from 0.7V to 5.5V using a resistive voltage-divider (Figure 6). The MAX8550/MAX8551 regulate fixed refer- ence voltage (0.7V). The adjusted output voltage is: ) IN(MAX) V OUT where ...
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... R D cal of systems with a mechanical switch or connector in series with the input. If the MAX8550/MAX8551 are operated as the second stage of a two-stage power conversion system, tantalum input capacitors are acceptable. In either configuration, choose a capacitor that has less than 10°C temperature rise at the RMS input current for optimal reliability and lifetime. × ...
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Integrated DDR Power-Supply Solutions for Desktops, Notebooks, and Graphic Cards The actual capacitance value required relates to the physical size needed to achieve low ESR, as well as to the chemistry of the capacitor technology. Thus, the capacitor is usually ...
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... VTTI input. If the latter is unavoidable, increase the amount of bypass capacitance at the VTTI input and add additional bypass at the REFIN pin. MOSFET Selection (Buck) The MAX8550/MAX8551 drive external, logic-level, N- channel MOSFETs as the circuit-switch elements. The key selection parameters: On-resistance (R ): the lower, the better. ...
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... Choose an R the specific application’s derating rule for the power dissipation calculated. The current-sense method used in the MAX8550/ MAX8551 makes use of the on-resistance (R the low-side MOSFET (Q2 in the Typical Applications Circuit). When calculating the current limit, use the worst- ...
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... Pick a percentage of foldback, PFB, from 15% to 40%. 3) Calculate the voltage, V ILIM(0V) shorted (0V): REF C REF MAX8550/ MAX8551 ILIM GND Figure 7. Foldback Current Limit ______________________________________________________________________________________ 4) The value for R4 can be calculated as: 5) The parallel combination of R5 and R6, denoted R56, is calculated as: to ILIM (R6 OUT ...
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... DD C BOOST where the total gate charge of the DD G high-side MOSFET, and C is the boost-capacitor BOOST 24 ______________________________________________________________________________________ C1 0.01µF REFIN C3 1µ MAX8550 10Ω 4.7µF CMOSH BST 10µF 0.22µ IRF7821 DH N-CHANNEL 30V, 9mW TOKO FDA1254-1R0M 1.0µ ...
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... AC and DC tolerance window in tight-tolerance applications. Figure 9 shows the connection of OUT and volt- greatly increases, age-positioned circuit. In nonvoltage-positioned cir- cuits, the MAX8550/MAX8551 regulate at the output capacitor. In voltage-positioned circuits, the MAX8550/ MAX8551 regulate on the inductor side of the voltage- , output SAG positioning resistor ...
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... For best performance, the VTTI bypass capacitor must be placed as close to VTTI (pin 13) as possible. REFIN (pin 14) should be separately routed with a clean trace and adequately bypassed to GND. Refer to the MAX8550 evaluation kit data sheet for PC board guidelines. +5V BIAS SUPPLY ...
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... GND C9 SS C10 REF R4 R5 ILIM FB R6 OUT ______________________________________________________________________________________ Typical Operating Circuit C1 0.01µF REFIN C3 1µ 10Ω MAX8550/ MAX8551 V IN BST PGND1 SHDNA ON SHDNB OFF STBY TRANSISTOR COUNT: 5100 PROCESS: BiCMOS 5V BIAS SUPPLY V (4.5V TO 28V ...
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Integrated DDR Power-Supply Solutions for Desktops, Notebooks, and Graphic Cards (The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information go to www.maxim-ic.com/packages.) D D/2 MARKING XXXXX PIN # 1 ...
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Integrated DDR Power-Supply Solutions for Desktops, Notebooks, and Graphic Cards (The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information go to www.maxim-ic.com/packages.) COMMON DIMENSIONS PKG. 16L 5x5 20L 5x5 ...