9-4023; Rev 0; 4/06 High-Efficiency, 5x Output, Main Power-Supply Controllers for Notebook Computers Features The MAX1533A/MAX1537A are dual step-down, switchmode power-supply (SMPS) controllers with synchronous rectification, intended for main 5V/3.3V power generation in battery-powered systems. Fixed-frequency operation with optimal interleaving minimizes input ripple current from the lowest input voltages up to the 26V maximum input. Optimal 40/60 interleaving allows the input voltage to go down to 8.
MAX1533A/MAX1537A High-Efficiency, 5x Output, Main Power-Supply Controllers for Notebook Computers ABSOLUTE MAXIMUM RATINGS IN, SHDN, INA, LDOA to GND ...............................-0.3V to +30V GND to PGND .......................................................-0.3V to +0.3V LDO5, LDO3, VCC to GND .......................................-0.3V to +6V ILIM3, ILIM5, PGDLY to GND...................................-0.3V to +6V CSL3, CSH3, CSL5, CSH5 to GND ..........................-0.
High-Efficiency, 5x Output, Main Power-Supply Controllers for Notebook Computers (Circuit of Figure 1, VIN = 12V, both SMPS enabled, VCC = 5V, FSEL = REF, SKIP = GND, VILIM_ = VLDO5, VINA = 15V, VLDOA = 12V, ILDO5 = ILDO3 = ILDOA = no load, TA = 0°C to +85°C, unless otherwise noted. Typical values are at TA = +25°C.
MAX1533A/MAX1537A High-Efficiency, 5x Output, Main Power-Supply Controllers for Notebook Computers ELECTRICAL CHARACTERISTICS (continued) (Circuit of Figure 1, VIN = 12V, both SMPS enabled, VCC = 5V, FSEL = REF, SKIP = GND, VILIM_ = VLDO5, VINA = 15V, VLDOA = 12V, ILDO5 = ILDO3 = ILDOA = no load, TA = 0°C to +85°C, unless otherwise noted. Typical values are at TA = +25°C.) PARAMETER MIN TYP MAX UNITS Standby mode, 6V < VIN < 26V, 0 < ILOAD < 100mA 3.20 3.35 3.
High-Efficiency, 5x Output, Main Power-Supply Controllers for Notebook Computers (Circuit of Figure 1, VIN = 12V, both SMPS enabled, VCC = 5V, FSEL = REF, SKIP = GND, VILIM_ = VLDO5, VINA = 15V, VLDOA = 12V, ILDO5 = ILDO3 = ILDOA = no load, TA = 0°C to +85°C, unless otherwise noted. Typical values are at TA = +25°C.
MAX1533A/MAX1537A High-Efficiency, 5x Output, Main Power-Supply Controllers for Notebook Computers ELECTRICAL CHARACTERISTICS (continued) (Circuit of Figure 1, VIN = 12V, both SMPS enabled, VCC = 5V, FSEL = REF, SKIP = GND, VILIM_ = VLDO5, VINA = 15V, VLDOA = 12V, ILDO5 = ILDO3 = ILDOA = no load, TA = 0°C to +85°C, unless otherwise noted. Typical values are at TA = +25°C.) PARAMETER SYMBOL CONDITIONS High FSEL Three-Level Input Logic MIN TYP REF 1.
High-Efficiency, 5x Output, Main Power-Supply Controllers for Notebook Computers (Circuit of Figure 1, VIN = 12V, both SMPS enabled, VCC = 5V, FSEL = REF, SKIP = GND, VILIM_ = VLDO5, VINA = 15V, VLDOA = 12V, ILDO5 = ILDO3 = ILDOA = no load, TA = -40°C to +85°C, unless otherwise noted.
MAX1533A/MAX1537A High-Efficiency, 5x Output, Main Power-Supply Controllers for Notebook Computers ELECTRICAL CHARACTERISTICS (continued) (Circuit of Figure 1, VIN = 12V, both SMPS enabled, VCC = 5V, FSEL = REF, SKIP = GND, VILIM_ = VLDO5, VINA = 15V, VLDOA = 12V, ILDO5 = ILDO3 = ILDOA = no load, TA = -40°C to +85°C, unless otherwise noted.
High-Efficiency, 5x Output, Main Power-Supply Controllers for Notebook Computers VIN = 7V 70 VIN = 12V VIN = 20V 60 0.01 0.1 MAX1533/37 toc02 4.96 10 5.04 5.00 4.96 4.92 SKIP = GND SKIP = VCC 4.88 0 1 2 3 4 5 6 5 10 15 20 25 LOAD CURRENT (A) INPUT VOLTAGE (V) PWM3 EFFICIENCY vs. LOAD CURRENT (VOUT3 = 3.3V) 3.3V OUTPUT VOLTAGE (OUT3) vs. LOAD CURRENT 3.3V OUTPUT VOLTAGE (OUT3) vs. INPUT VOLTAGE 70 VIN = 12V 3.33 3.30 3.27 NO LOAD 3.
Typical Operating Characteristics (continued) (MAX1537A circuit of Figure 1, VIN = 12V, LDO5 = VCC = 5V, SKIP = GND, FSEL = REF, TA = +25°C, unless otherwise noted.) 2.0 1.5 1.0 LDO DEVIATION VOLTAGE (mV) 2.5 50 MAX1533 toc11 DUTY CYCLE LIMITED 2.01 REF VOLTAGE (V) PEAK CURRENT (A) 2.02 MAX1533/37 toc10 3.5 3.0 LINEAR-REGULATOR LOAD REGULATION 2.0V REFERENCE LOAD REGULATION 2.00 1.99 0.5 MAX1533/37 toc12 IDLE-MODE CURRENT vs.
High-Efficiency, 5x Output, Main Power-Supply Controllers for Notebook Computers DELAYED STARTUP WAVEFORM (LIGHT LOAD) STARTUP WAVEFORM (HEAVY LOAD) 3.3V A 0 5V SHUTDOWN WAVEFORM (NO LOAD) MAX1533/37 toc17 MAX1533/37 toc16 3.3V 0 MAX1533/37 toc18 A 4V B 2V 0 3.3V C 0 B 0 5V C 0 3.3V 0 D 5V E 0 E F 0 2ms/div A. SHDN, 5V/div D. 3.3V OUTPUT, 5V/div B. 5V OUTPUT, 5V/div E. DL3, 5V/div C. DL5, 5V/div F.
MAX1533A/MAX1537A High-Efficiency, 5x Output, Main Power-Supply Controllers for Notebook Computers Typical Operating Characteristics (continued) (MAX1537A circuit of Figure 1, VIN = 12V, LDO5 = VCC = 5V, SKIP = GND, FSEL = REF, TA = +25°C, unless otherwise noted.) OUTPUT OVERLOAD (UVP ENABLED) 3.3V OUTPUT LOAD TRANSIENT (PULSE SKIPPING) 4A 5V A 0 MAX1533/37 toc24 A 0 3.3V 3.
High-Efficiency, 5x Output, Main Power-Supply Controllers for Notebook Computers PIN MAX1533A MAX1537A — 1 1 2 NAME FUNCTION ADJA Auxiliary Feedback Input. Connect a resistive voltage-divider from LDOA to analog ground to adjust the auxiliary linear-regulator output voltage. ADJA regulates at 2V. Connect ADJA to GND for nominal 12V output using internal feedback. ON5 5V SMPS Enable Input.
MAX1533A/MAX1537A High-Efficiency, 5x Output, Main Power-Supply Controllers for Notebook Computers Pin Description (continued) PIN MAX1533A 14 MAX1537A NAME FUNCTION Open-Drain Power-Good Output. PGOOD is low if either output is more than 10% (typ) below the normal regulation point, during soft-start, and in shutdown. PGOOD is delayed on the rising edge by the PGDLY one-shot timer. PGOOD becomes high impedance when both SMPS outputs are in regulation.
High-Efficiency, 5x Output, Main Power-Supply Controllers for Notebook Computers PIN NAME FUNCTION MAX1533A MAX1537A 25 27 CSL5 Negative Current-Sense Input for 5V SMPS. Connect to the negative terminal of the current-sense element. Figure 9 describes two different current-sensing options. CSL5 also serves as the bootstrap input for LDO5. 26 28 CSH5 Positive Current-Sense Input for 5V SMPS. Connect to the positive terminal of the current-sense element.
MAX1533A/MAX1537A High-Efficiency, 5x Output, Main Power-Supply Controllers for Notebook Computers Table 1. Component Selection for Standard Applications COMPONENT 5A/300kHz 5A/500kHz Input Voltage VIN = 7V to 24V VIN = 7V to 24V (2) 10µF, 25V Taiyo Yuden TMK432BJ106KM (2) 10µF, 25V Taiyo Yuden TMK432BJ106KM COUT5, Output Capacitor 150µF, 6.3V, 40mΩ, low-ESR capacitor Sanyo 6TPB150ML 150µF, 6.
High-Efficiency, 5x Output, Main Power-Supply Controllers for Notebook Computers MAX1533A/MAX1537A INPUT (VIN) 5V LDO OUTPUT C1 10μF IN LDO5 DBST NH1 DL1 L1 5.8μH DBST DH3 CBST 0.1μF CIN (2) 10μF BST3 MAX1533A MAX1537A C5 22μF NH2 DH5 BST5 SECONDARY OUTPUT CBST 0.1μF LX3 LX5 DL3 DL5 NL1 D1 DL2 T1 1:2 TURNS LP = 6.8μH NL2 PGND GND RCS1 10mΩ 3.3V PWM OUTPUT COUT1 220μF 40mΩ CREF 0.22μF R3 60.
MAX1533A/MAX1537A High-Efficiency, 5x Output, Main Power-Supply Controllers for Notebook Computers SMPS to LDO Bootstrap Switchover When the 5V main output voltage is above the LDO5 bootstrap-switchover threshold, an internal 0.75Ω (typ) p-channel MOSFET shorts CSL5 to LDO5 while simultaneously shutting down the LDO5 linear regulator. Similarly, when the 3.
High-Efficiency, 5x Output, Main Power-Supply Controllers for Notebook Computers MAX1533A/MAX1537A LDO3 IN 5V LINEAR REGULATOR 3.
MAX1533A/MAX1537A High-Efficiency, 5x Output, Main Power-Supply Controllers for Notebook Computers Table 3. Operating Modes MODE INPUTS* OUTPUTS SHDN ON5 ON3 LDO5 LDO3 5V SMPS 3V SMPS Shutdown Mode LOW X X OFF OFF OFF OFF Standby Mode HIGH LOW LOW ON ON OFF OFF Normal Operation HIGH HIGH HIGH ON ON ON ON 3.3V SMPS Active HIGH LOW HIGH ON ON OFF ON 5V SMPS Active HIGH HIGH LOW ON ON ON OFF ON ON Power-up after 3.
High-Efficiency, 5x Output, Main Power-Supply Controllers for Notebook Computers (SEE FIGURE 5) CSL REF/2 SLOPE COMP GND 0.2 x VLIMIT R Q IDLEMODE CURRENT S DH DRIVER SKIP SOFT-START COUNTER ON DAC CURRENT LIMIT OSC -1.2 x VLIMIT S R Q DL DRIVER LX PGND MAX1537A ONLY 0.
MAX1533A/MAX1537A High-Efficiency, 5x Output, Main Power-Supply Controllers for Notebook Computers Frequency Selection (FSEL) The FSEL input selects the PWM-mode switching frequency. Table 4 shows the switching frequency based on FSEL connection. High-frequency (500kHz) operation optimizes the application for the smallest component size, trading off efficiency due to higher switching losses. This may be acceptable in ultra-portable devices where the load currents are lower.
High-Efficiency, 5x Output, Main Power-Supply Controllers for Notebook Computers MAX1533A/MAX1537A TO ERROR AMPLIFIER ADJUSTABLE OUTPUT FB REF (2.0V) INDUCTOR CURRENT I L tON(SKIP) ≥ IDLE VIN - VOUT 12R R ILOAD(SKIP) FIXED OUTPUT FB = GND CSL 0 ON-TIME TIME Figure 4. Pulse-Skipping/Discontinuous Crossover Point Figure 5. Dual-Mode Feedback Decoder Output Voltage DC output accuracy specifications in the Electrical Characteristics table refer to the error-comparator’s threshold.
MAX1533A/MAX1537A High-Efficiency, 5x Output, Main Power-Supply Controllers for Notebook Computers When adjusting both output voltages, set the 3.3V SMPS lower than the 5V SMPS. LDO5 connects to the 5V output (CSL5) through an internal switch only when CSL5 is above the LDO5 bootstrap threshold (4.56V). Similarly, LDO3 connects to the 3.3V output (CSL3) through an internal switch only when CSL3 is above the LDO3 bootstrap threshold (2.91V).
High-Efficiency, 5x Output, Main Power-Supply Controllers for Notebook Computers CBYP MAX1533A MAX1537A LDO5 BST (RBST)* DBST INPUT (VIN) CBST DH NH L LX LDO5 DL NL (CNL)* GND Fault Protection Output Overvoltage Protection (OVP) If the output voltage of either SMPS rises above 111% of its nominal regulation voltage and the OVP protection is enabled (OVP = GND), the controller sets the fault latch, pulls PGOOD low, shuts down both SMPS controllers, and immediately pulls DH_ low and forces DL_ (R
MAX1533A/MAX1537A High-Efficiency, 5x Output, Main Power-Supply Controllers for Notebook Computers high. This turns on the synchronous-rectifier MOSFETs with 100% duty, rapidly discharging the output capacitors and clamping both outputs to ground. However, immediately latching DL_ high typically causes slightly negative output voltages due to the energy stored in the output LC at the instant the OVP occurs.
High-Efficiency, 5x Output, Main Power-Supply Controllers for Notebook Computers Auxiliary LDO Detailed Description (MAX1537A Only) The MAX1537A includes an auxiliary linear regulator that delivers up to 150mA of load current. The output (LDOA) can be preset to 12V, ideal for PCMCIA power requirements, and for biasing the gates of load switches in a portable device. In adjustable mode, LDOA can be set to anywhere from 5V to 23V.
MAX1533A/MAX1537A High-Efficiency, 5x Output, Main Power-Supply Controllers for Notebook Computers • Maximum Load Current. There are two values to consider. The peak load current (ILOAD(MAX)) determines the instantaneous component stresses and filtering requirements and thus drives output-capacitor selection, inductor saturation rating, and the design of the current-limit circuit.
High-Efficiency, 5x Output, Main Power-Supply Controllers for Notebook Computers N= VSEC + VFWD VOUT5 + VRECT + VSENSE where V SEC is the minimum required rectified secondary voltage, VFWD is the forward drop across the secondary rectifier, VOUT5(MIN) is the minimum value of the main output voltage, and VRECT is the on-state voltage drop across the synchronous-rectifier MOSFET.
MAX1533A/MAX1537A High-Efficiency, 5x Output, Main Power-Supply Controllers for Notebook Computers 9a. This configuration constantly monitors the inductor current, allowing accurate current-limit protection. Alternatively, high-power applications that do not require highly accurate current-limit protection may reduce the overall power dissipation by connecting a series RC circuit across the inductor (Figure 9b) with an equivalent time constant: where RL is the inductor’s series DC resistance.
High-Efficiency, 5x Output, Main Power-Supply Controllers for Notebook Computers VRIPPLE(P − P) = RESR ILOAD(MAX) LIR In idle mode, the inductor current becomes discontinuous, with peak currents set by the idle-mode currentsense threshold (VIDLE = 0.2VLIMIT).
The 40/60 optimal interleaved architecture of the MAX1533A/MAX1537A allows the input voltage to go as low as 8.3V before the duty cycles begin to overlap. This offers improved efficiency over a regular 180° outof-phase architecture where the duty cycles begin to overlap below 10V. Figure 10 shows the input-capacitor RMS current vs. input voltage for an application that requires 5V/5A and 3.3V/5A. This shows the improvement of the 40/60 optimal interleaving over 50/50 interleaving and in-phase operation.
High-Efficiency, 5x Output, Main Power-Supply Controllers for Notebook Computers Switching losses in the high-side MOSFET can become a heat problem when maximum AC-adapter voltages are applied, due to the squared term in the switchingloss equation (C x VIN2 x fSW). If the high-side MOSFET chosen for adequate RDS(ON) at low battery voltages becomes extraordinarily hot when subjected to V IN(MAX) , consider choosing another MOSFET with lower parasitic capacitance.
MAX1533A/MAX1537A High-Efficiency, 5x Output, Main Power-Supply Controllers for Notebook Computers above the feedback-threshold voltage, the controller does not trigger an on-time pulse, effectively skipping a cycle. This allows the controller to maintain regulation above the maximum input voltage, but forces the controller to effectively operate with a lower switching frequency.
High-Efficiency, 5x Output, Main Power-Supply Controllers for Notebook Computers MAX1533A/MAX1537A CONNECT GND AND PGND TO THE CONTROLLER AT ONE POINT ONLY AS SHOWN CONNECT THE EXPOSED PAD TO ANALOG GND VIA TO POWER GROUND VIA TO REF BYPASS CAPACITOR VIA TO REF PIN VIA TO VCC BYPASS CAPACITOR MAX1533A TOP LAYER MAX1533A BOTTOM LAYER KELVIN-SENSE VIAS UNDER THE SENSE RESISTOR (SEE THE EVALUATION KIT) VIA TO VCC PIN DUAL n-CHANNEL MOSFET INDUCTOR SINGLE n-CHANNEL MOSFETS INDUCTOR DH LX DL COUT C
High-Efficiency, 5x Output, Main Power-Supply Controllers for Notebook Computers TRANSISTOR COUNT: 6890 PROCESS: BiCMOS CSL5 FB5 ADJA ON5 1 27 2 26 ON3 ONA 3 25 4 24 FSEL ILIM3 5 ILIM5 REF GND 7 21 8 20 PGND DL3 LDO3 FB3 9 19 CSL3 23 16 17 18 OVP CSH3 15 14 11 12 10 22 VCC 13 MAX1537A 6 Chip Information 28 29 30 31 SKIP DH5 BST5 LX5 IN CSH5 33 32 INA SHDN 35 34 LDOA 36 TOP VIEW PGDLY PGOOD UVP DH3 BST3 LX3 MAX1533A/MAX1537A Pin Configurations (continued)
High-Efficiency, 5x Output, Main Power-Supply Controllers for Notebook Computers QFN THIN.EPS ______________________________________________________________________________________ 37 MAX1533A/MAX1537A Package Information (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.
Package Information (continued) (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.) QFN THIN.EPS MAX1533A/MAX1537A High-Efficiency, 5x Output, Main Power-Supply Controllers for Notebook Computers Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied.
