EVALUATION KIT AVAILABLE MAX5033 500mA, 76V, High-Efficiency, MAXPower Step-Down DC-DC Converter General Description The MAX5033 easy-to-use, high-efficiency, high-voltage, step-down DC-DC converter operates from an input voltage up to 76V and consumes only 270A quiescent current at no load. This pulse-width modulated (PWM) converter operates at a fixed 125kHz switching frequency at heavy loads, and automatically switches to pulseskipping mode to provide low quiescent current and high efficiency at light loads. The MAX5033 includes internal frequency compensation simplifying circuit implementation. The device uses an internal low-onresistance, high-voltage, DMOS transistor to obtain high efficiency and reduce overall system cost. This device includes undervoltage lockout, cycle-by-cycle current limit, hiccup-mode output short-circuit protection, and thermal shutdown. The MAX5033 delivers up to 500mA output current. The output current may be limited by the maximum power dissipation capability of the package. External shutdown is included, featuring 10A (typ) shutdown current. The MAX5033A/B/C versions have fixed output voltages of 3.3V, 5V, and 12V, respectively, while the MAX5033D features an adjustable output voltage, from 1.25V to 13.2V. Features Wide 7.5V to 76V Input Voltage Range Fixed (3.3V, 5V, 12V) and Adjustable (1.25V to 13.2V) Voltage Versions 500mA Output Current Efficiency Up to 94% Internal 0.4 High-Side DMOS FET 270A Quiescent Current at No Load, 10A Shutdown Current Internal Frequency Compensation Fixed 125kHz Switching Frequency Thermal Shutdown and Short-Circuit Current Limit 8-Pin SO and PDIP Packages Ordering Information PINPACKAGE PART TEMP RANGE MAX5033AUSA 0C to +85C 8 SO The MAX5033 is available in space-saving 8-pin SO and 8-pin plastic DIP packages and operates over the automotive (-40C to +125C) temperature range. MAX5033AUPA 0C to +85C 8 PDIP MAX5033BUSA 0C to +85C 8 SO Applications MAX5033BUPA 0C to +85C 8 PDIP MAX5033AASA MAX5033BASA Consumer Electronics Industrial Distributed Power 0C to +85C 8 SO MAX5033CUPA 0C to +85C 8 PDIP MAX5033DASA VIN 47F BST 0.1F MAX5033 220H LX R1 ON/OFF ON OFF R2 D1 50SQ100 GND 0C to +85C 8 SO 0C to +85C 8 PDIP VD 0.1F This product is available in both leaded(Pb) and lead(Pb)-free packages. To order the lead(Pb)-free package, add a + after the part number. Pin Configuration BST 1 8 LX VD 2 7 VIN SGND 3 6 GND FB 4 5 ON/OFF MAX5033 SO/PDIP 19-2979; Rev 5; 4/14 ADJ -40C to +125C 8 SO 33F FB SGND VOUT 5V, 0.5A 12 -40C to +125C 8 SO MAX5033DUPA VIN 7.5V TO 76V 5.0 -40C to +125C 8 SO MAX5033DUSA Typical Application Circuit 3.3 -40C to +125C 8 SO MAX5033CUSA MAX5033CASA OUTPUT VOLTAGE (V) MAX5033 500mA, 76V, High-Efficiency, MAXPower Step-Down DC-DC Converter Absolute Maximum Ratings (Voltages referenced to GND, unless otherwise specified.) VIN .........................................................................-0.3V to +80V SGND ....................................................................-0.3V to +0.3V LX.................................................................-0.8V to (VIN + 0.3V) BST...............................................................-0.3V to (VIN + 10V) BST (transient < 100ns)................................-0.3V to (VIN + 15V) BST to LX................................................................-0.3V to +10V BST to LX (transient < 100ns) ................................-0.3V to +15V ON/OFF ..................................................................-0.3V to +80V VD...........................................................................-0.3V to +12V FB MAX5033A/MAX5033B/MAX5033C...................-0.3V to +15V MAX5033D.........................................................-0.3V to +12V VOUT Short-Circuit Duration (VIN 40V).....................Indefinite VD Short-Circuit Duration..............................................Indefinite Continuous Power Dissipation (TA = +70C) 8-Pin PDIP (derate 9.1mW/C above +70C)..............727mW 8-Pin SO (derate 5.9mW/C above +70C)..................471mW Operating Temperature Range MAX5033_U_ _...................................................0C to +85C MAX5033_A_ _..............................................-40C to +125C Storage Temperature Range.............................-65C to +150C Junction Temperature.......................................................+150C Lead Temperature (soldering, 10s)...................................+300C Soldering Temperature (reflow) SO, PDIP Lead(Pb)-free...............................................+260C SO, PDIP Containing lead (Pb)....................................+240C Stresses beyond those listed under "Absolute Maximum Ratings" may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. Electrical Characteristics (MAX5033_U_ _) (VIN = +12V, VON/OFF = +12V, IOUT = 0, TA = 0C to +85C, unless otherwise noted. Typical values are at TA = +25C. See the Typical Operating Circuit.) PARAMETER Input Voltage Range Undervoltage Lockout Output Voltage Feedback Voltage Efficiency Quiescent Supply Current Shutdown Current SYMBOL VIN CONDITIONS VFB IQ ISHDN MAX 76.0 MAX5033B 7.5 76.0 MAX5033C 15 76 MAX5033D 7.5 76.0 UVLO VOUT TYP 7.5 5.2 3.185 3.3 3.415 MAX5033B, VIN = 7.5V to 76V, IOUT = 20mA to 500mA 4.85 5.0 5.15 MAX5033C, VIN = 15V to 76V, IOUT = 20mA to 500mA 11.64 12 12.36 VIN = 7.5V to 76V, MAX5033D 1.192 1.221 1.250 VIN = 12V, ILOAD = 500mA, MAX5033A 86 VIN = 12V, ILOAD = 500mA, MAX5033B 90 VIN = 24V, ILOAD = 500mA, MAX5033C 94 VIN = 12V, VOUT = 5V, ILOAD = 500mA, MAX5033D 90 VFB = 3.5V, VIN = 7.5V to 76V, MAX5033A 270 440 VFB = 5.5V, VIN = 7.5V to 76V, MAX5033B 270 440 VFB = 13V, VIN = 15V to 76V, MAX5033C 270 440 VFB = 1.3V, MAX5033D 270 440 VON/OFF = 0V, VIN = 7.5V to 76V 10 45 1.5 2.1 ILIM (Note 1) Switch Leakage Current IOL VIN = 76V, VON/OFF = 0V, VLX = 0V 0.95 1 UNITS V V MAX5033A, VIN = 7.5V to 76V, IOUT = 20mA to 500mA Peak Switch Current Limit www.maximintegrated.com MIN MAX5033A V V % A A A A Maxim Integrated 2 MAX5033 500mA, 76V, High-Efficiency, MAXPower Step-Down DC-DC Converter Electrical Characteristics (MAX5033_U_ _) (continued) (VIN = +12V, VON/OFF = +12V, IOUT = 0, TA = 0C to +85C, unless otherwise noted. Typical values are at TA = +25C. See the Typical Operating Circuit.) PARAMETER Switch On-Resistance PFM Threshold FB Input Bias Current SYMBOL RDS(ON) IPFM IB CONDITIONS MIN ISWITCH = 500mA Minimum switch current in any cycle TYP MAX UNITS 0.4 0.80 35 65 95 mA MAX5033D -150 +0.01 +150 nA Rising trip point 1.53 1.69 1.85 ON/OFF CONTROL INPUT ON/OFF Input-Voltage Threshold VON/OFF ON/OFF Input-Voltage Hysteresis VHYST ON/OFF Input Current ON/OFF Operating Voltage Range ION/OFF 100 10 VON/OFF = 0V to VIN VON/OFF V mV 150 nA 76 V 135 kHz OSCILLATOR Oscillator Frequency fOSC Maximum Duty Cycle DMAX 109 MAX5033D 125 95 % VOLTAGE REGULATOR Regulator Output Voltage VD Dropout Voltage Load Regulation VIN = 8.5V to 76V, IL = 0mA 6.9 7.5V VIN 8.5V, IL = 1mA VD/IVD 0 to 5mA 7.8 8.8 V 2.0 V 150 PACKAGE THERMAL CHARACTERISTICS Thermal Resistance (Junction to Ambient) JA SO package (JEDEC 51) 170 DIP package (JEDEC 51) 110 C/W THERMAL SHUTDOWN Thermal-Shutdown Junction Temperature Thermal-Shutdown Hysteresis TSH +160 C THYST 20 C Electrical Characteristics (MAX5033_A_ _) (VIN = +12V, VON/OFF = +12V, IOUT = 0, TA = TJ = -40C to +125C, unless otherwise noted. Typical values are at TA = +25C. See the Typical Operating Circuit.) (Note 2) PARAMETER Input Voltage Range Undervoltage Lockout Output Voltage www.maximintegrated.com SYMBOL VIN CONDITIONS MIN MAX 7.5 76.0 MAX5033B 7.5 76.0 MAX5033C 15 76 MAX5033D 7.5 76.0 UVLO VOUT TYP MAX5033A 5.2 UNITS V V MAX5033A, VIN = 7.5V to 76V, IOUT = 20mA to 500mA 3.185 3.3 3.415 MAX5033B, VIN = 7.5V to 76V, IOUT = 20mA to 500mA 4.825 5.0 5.175 MAX5033C, VIN = 15V to 76V, IOUT = 20mA to 500mA 11.58 12 12.42 V Maxim Integrated 3 MAX5033 500mA, 76V, High-Efficiency, MAXPower Step-Down DC-DC Converter Electrical Characteristics (MAX5033_A_ _) (continued) (VIN = +12V, VON/OFF = +12V, IOUT = 0, TA = TJ = -40C to +125C, unless otherwise noted. Typical values are at TA = +25C. See the Typical Operating Circuit.) (Note 2) PARAMETER Feedback Voltage Efficiency Quiescent Supply Current Shutdown Current Peak Switch Current Limit Switch Leakage Current Switch On-Resistance PFM Threshold FB Input Bias Current SYMBOL VFB IQ ISHDN CONDITIONS VIN = 7.5V to 76V, MAX5033D UNITS V 86 90 VIN = 24V, ILOAD = 500mA, MAX5033C 94 VIN = 12V, VOUT = 5V, ILOAD = 500mA, MAX5033D 90 VFB = 3.5V, VIN = 7.5V to 76V, MAX5033A 270 440 VFB = 5.5V, VIN = 7.5V to 76V, MAX5033B 270 440 VFB = 13V, VIN = 15V to 76V, MAX5033C 270 440 VFB = 1.3V, MAX5033D 270 440 VON/OFF = 0V, VIN = 7.5V to 76V 10 45 A 1.5 2.1 A IOL VIN = 76V, VON/OFF = 0V, VLX = 0V IB MAX 1.250 VIN = 12V, ILOAD = 500mA, MAX5033B (Note 1) IPFM TYP 1.221 VIN = 12V, ILOAD = 500mA, MAX5033A ILIM RDS(ON) MIN 1.192 0.95 1 ISWITCH = 500mA Minimum switch current in any cycle % 0.4 A A 0.80 35 65 110 mA MAX5033D -150 +0.01 +150 nA Rising trip point 1.50 1.69 1.85 ON/OFF CONTROL INPUT ON/OFF Input-Voltage Threshold VON/OFF ON/OFF Input-Voltage Hysteresis VHYST ON/OFF Input Current ON/OFF Operating Voltage Range ION/OFF 100 10 VON/OFF = 0V to VIN VON/OFF V mV 150 nA 76 V 137 kHz OSCILLATOR Oscillator Frequency fOSC Maximum Duty Cycle DMAX 105 MAX5033D 125 95 % VOLTAGE REGULATOR Regulator Output Voltage VD Dropout Voltage Load Regulation VIN = 8.5V to 76V, IL = 0mA 7.5V VIN 8.5V, IL = 1mA VD/IVD 0 to 5mA 6.5 7.8 9.0 V 2.0 V 150 PACKAGE THERMAL CHARACTERISTICS Thermal Resistance (Junction to Ambient) JA SO package (JEDEC 51) 170 DIP package (JEDEC 51) 110 C/W THERMAL SHUTDOWN Thermal-Shutdown Junction Temperature Thermal-Shutdown Hysteresis TSH +160 C THYST 20 C Note 1: Switch current at which the current limit is activated. Note 2: All limits at -40C are guaranteed by design, not production tested. www.maximintegrated.com Maxim Integrated 4 MAX5033 500mA, 76V, High-Efficiency, MAXPower Step-Down DC-DC Converter Typical Operating Characteristics (VIN = 12V, VON/OFF = 12V, TA = -40C to +125C, unless otherwise noted. Typical values are at TA = +25C. See the Typical Operating Circuit, if applicable.) 12.3 IOUT = 0.1A 5.05 12.3 5.00 VOUT (V) 12.1 12.0 12.4 12.2 IOUT = 0.1A VOUT (V) IOUT = 0.5A IOUT = 0.5A 4.95 11.9 25 0 4.90 100 125 150 75 50 -50 -25 LINE REGULATION (MAX5033BASA, VOUT = 5V) 50 75 100 125 150 TEMPERATURE (C) 12.3 VOUT (V) IOUT = 0.5A 30 VIN = 24V 12.1 12.0 VIN = 76V 4.95 40 50 60 70 80 LOAD REGULATION (MAX5033BASA, VOUT = 5V) VIN = 7.5V, 24V 5.05 12.2 5.00 20 5.10 MAX5033 toc05 IOUT = 0A 5.05 10 INPUT VOLTAGE (V) LOAD REGULATION (MAX5033CASA, VOUT = 12V) 12.4 MAX5033 toc04 5.10 11.8 25 0 VOUT (V) -50 -25 TEMPERATURE (C) VOUT (V) 12.1 12.0 IOUT = 0.5A 11.9 11.8 IOUT = 0A MAX5033 toc06 VOUT (V) 12.2 LINE REGULATION (MAX5033CASA, VOUT = 12V) MAX5033 toc03 5.10 MAX5033 toc01 12.4 VOUT vs. TEMPERATURE (MAX5033BASA, VOUT = 5V) MAX5033 toc02 VOUT vs. TEMPERATURE (MAX5033CASA, VOUT = 12V) 5.00 VIN = 76V 4.95 11.9 26 36 46 56 66 300 400 4.90 500 0 100 200 300 400 EFFICIENCY vs. LOAD CURRENT (MAX5033BASA, VOUT = 5V) EFFICIENCY vs. LOAD CURRENT (MAX5033CASA, VOUT = 12V) OUTPUT CURRENT LIMIT vs. TEMPERATURE 60 VIN = 24V 50 VIN = 76V 90 80 VIN = 48V 30 70 60 30 20 10 300 LOAD CURRENT (mA) www.maximintegrated.com 400 500 VIN = 24V VIN = 48V 40 10 200 VIN = 76V 50 20 100 VIN = 15V 0 0 100 200 300 LOAD CURRENT (mA) 400 500 2.0 500 MAX5033 toc09 100 OUTPUT CURRENT LIMIT (A) VIN = 7.5V VIN = 12V 0 200 ILOAD (mA) 70 0 100 ILOAD (mA) 80 40 0 INPUT VOLTAGE (V) 90 EFFICIENCY (%) 11.8 76 MAX5033 toc07 100 16 MAX5033 toc08 6 EFFICIENCY (%) 4.90 1.7 1.4 1.1 0.8 0.5 MAX5033BASA 5% DROP IN VOUT -50 -25 0 25 50 75 100 125 150 TEMPERATURE (C) Maxim Integrated 5 MAX5033 500mA, 76V, High-Efficiency, MAXPower Step-Down DC-DC Converter Typical Operating Characteristics (continued) (VIN = 12V, VON/OFF = 12V, TA = -40C to +125C, unless otherwise noted. Typical values are at TA = +25C. See the Typical Operating Circuit, if applicable.) 1.4 1.1 MAX5033BASA VOUT = 5V 5% DROP IN VOUT 0.8 16 36 46 56 66 240 -50 -25 25 0 75 50 260 230 200 100 125 150 MAX5033 toc12 290 6 16 26 36 46 56 INPUT VOLTAGE (V) SHUTDOWN CURRENT vs. TEMPERATURE SHUTDOWN CURRENT vs. INPUT VOLTAGE OUTPUT VOLTAGE vs. INPUT VOLTAGE 5 0 20 15 10 5 0 25 50 75 100 125 150 TEMPERATURE (C) MAX5033BASA LOAD-TRANSIENT RESPONSE MAX5033 toc16 76 MAX5033CASA VOUT = 12V VON/OFF = VIN 12 9 IOUT = 0.3A IOUT = 0.5A 6 3 6 16 26 36 46 56 66 0 76 0 3 6 9 12 INPUT VOLTAGE (V) VIN (V) MAX5033BASA LOAD-TRANSIENT RESPONSE MAX5033BASA LOAD-TRANSIENT RESPONSE MAX5033 toc17 VOUT = 5V 15 VOUT (V) 10 25 66 MAX5033 toc15 TEMPERATURE (C) 15 -50 -25 280 320 INPUT VOLTAGE (V) 20 0 320 200 76 MAX5033 toc13 SHUTDOWN CURRENT (A) 25 26 360 QUIESCENT SUPPLY CURRENT vs. INPUT VOLTAGE 350 MAX5033 toc14 6 SHUTDOWN CURRENT (A) 0.5 MAX5033 toc11 1.7 400 QUIESCENT SUPPLY CURRENT (A) MAX5033 toc10 OUTPUT CURRENT LIMIT (A) 2.0 QUIESCENT SUPPLY CURRENT vs. TEMPERATURE QUIESCENT SUPPLY CURRENT (A) OUTPUT CURRENT LIMIT vs. INPUT VOLTAGE 15 MAX5033 toc18 VOUT = 5V VOUT = 5V A A A B B B 400s/div A: VOUT, 200mV/div, AC-COUPLED B: IOUT, 500mA/div, 100mA TO 500mA www.maximintegrated.com 400s/div A: VOUT, 100mV/div, AC-COUPLED B: IOUT, 200mA/div, 100mA TO 250mA 400s/div A: VOUT, 100mV/div, AC-COUPLED B: IOUT, 500mA/div, 250mA TO 500mA Maxim Integrated 6 MAX5033 500mA, 76V, High-Efficiency, MAXPower Step-Down DC-DC Converter Typical Operating Characteristics (continued) (VIN = 12V, VON/OFF = 12V, TA = -40C to +125C, unless otherwise noted. Typical values are at TA = +25C. See the Typical Operating Circuit, if applicable.) MAX5033BASA LX WAVEFORMS MAX5033BASA LX WAVEFORMS MAX5033BASA LX WAVEFORMS MAX5033 toc20 MAX5033 toc19 MAX5033 toc21 A A A 0 0 0 B B B 0 0 4s/div 4s/div A: SWITCH VOLTAGE, 20V/div, VIN = 48V B: INDUCTOR CURRENT, 100mA/div (IOUT = 30mA) MAX5033BASA STARTUP WAVEFORM (IO = 0) MAX5033BASA STARTUP WAVEFORM (IO = 0.5A) MAX5033 toc23 A A B B 1ms/div 1ms/div www.maximintegrated.com A: VON/OFF, 2V/div B: VOUT, 2V/div PEAK SWITCH CURRENT LIMIT vs. INPUT VOLTAGE 2.0 PEAK SWITCH CURRENT LIMIT (A) MAX5033 toc22 A: VON/OFF, 2V/div B: VOUT, 2V/div A: SWITCH VOLTAGE (LX PIN), 20V/div, VIN = 48V B: INDUCTOR CURRENT, 100mA/div (IOUT = 0) MAX5033 toc24 4ms/div A: SWITCH VOLTAGE (LX PIN) 20V/div, VIN = 48V B: INDUCTOR CURRENT, 200mA/div, (IOUT = 500mA) 1.7 1.4 1.1 0.8 0.5 MAX5033BASA VOUT = 5V 5% DROP IN VOUT 6 16 26 36 46 56 66 76 INPUT VOLTAGE (V) Maxim Integrated 7 MAX5033 500mA, 76V, High-Efficiency, MAXPower Step-Down DC-DC Converter Pin Description PIN NAME 1 BST Boost Capacitor Connection. Connect a 0.1F ceramic capacitor from BST to LX. FUNCTION 2 VD Internal Regulator Output. Bypass VD to GND with a 0.1F ceramic capacitor. 3 SGND 4 FB 5 ON/OFF 6 GND 7 VIN Input Voltage. Bypass VIN to GND with a low-ESR capacitor as close to the device as possible. 8 LX Source Connection of Internal High-Side Switch. Internal Connection. SGND must be connected to GND. Output Sense Feedback Connection. For fixed output voltage (MAX5033A, MAX5033B, MAX5033C), connect FB to VOUT. For adjustable output voltage (MAX5033D), use an external resistive voltagedivider to set VOUT. VFB regulating set point is 1.22V. Shutdown Control Input. Pull ON/OFF low to put the device in shutdown mode. Drive ON/OFF high for normal operation. Ground. Simplified Block Diagram VIN ON/OFF ENABLE REGULATOR (FOR ANALOG) 1.69V REGULATOR (FOR DRIVER) VD CPFM OSC VREF IREF-PFM HIGH-SIDE CURRENT SENSE CILIM RAMP IREF-LIM BST MAX5033 CLK FB RAMP CONTROL LOGIC Rh x1 Rl TYPE 3 COMPENSATION VREF EAMP THERMAL SHUTDOWN CPWM GND LX SGND www.maximintegrated.com Maxim Integrated 8 MAX5033 Detailed Description The MAX5033 step-down DC-DC converter operates from a 7.5V to 76V input voltage range. A unique voltage- mode control scheme with voltage feed-forward and an internal switching DMOS FET provides high efficiency over a wide input voltage range. This pulsewidth modulated converter operates at a fixed 125kHz switching frequency. The device also features automatic pulse-skipping mode to provide low quiescent current and high efficiency at light loads. Under no load, the MAX5033 consumes only 270A, and in shutdown mode, consumes only 10A. The MAX5033 also features undervoltage lockout, hiccup-mode output shortcircuit protection, and thermal shutdown. Shutdown Mode Drive ON/OFF to ground to shut down the MAX5033. Shutdown forces the internal power MOSFET off, turns off all internal circuitry, and reduces the VIN supply current to 10A (typ). The ON/OFF rising threshold is 1.69V (typ). Before any operation begins, the voltage at ON/OFF must exceed 1.69V (typ). The ON/OFF input has 100mV hysteresis. Undervoltage Lockout (UVLO) Use the ON/OFF function to program the UVLO threshold at the input. Connect a resistive voltage-divider from VIN to GND with the center node to ON/OFF as shown in Figure 1. Calculate the threshold value by using the following formula: R1 VUVLO(TH) = 1 + R2 x 1.85V The minimum recommended VUVLO(TH) is 6.5V, 7.5V, and 13V for the output voltages of 3.3V, 5V, and 12V, respectively. The recommended value for R2 is less than 1M. If the external UVLO threshold-setting divider is not used, an internal undervoltage-lockout feature monitors the supply voltage at VIN and allows operation to start when VIN rises above 5.2V (typ). This feature can be used only when VIN rise time is faster than 2ms. For slower VIN rise time, use the resistive divider at ON/OFF. 500mA, 76V, High-Efficiency, MAXPower Step-Down DC-DC Converter On startup, an internal low-side switch connects LX to ground and charges the BST capacitor to VD. Once the BST capacitor is charged, the internal low-side switch is turned off and the BST capacitor voltage provides the necessary enhancement voltage to turn on the high-side switch. Thermal-Overload Protection The MAX5033 features integrated thermal-overload protection. Thermal-overload protection limits total power dissipation in the device, and protects the device in the event of a fault condition. When the die temperature exceeds +160C, an internal thermal sensor signals the shutdown logic, turning off the internal power MOSFET and allowing the IC to cool. The thermal sensor turns the internal power MOSFET back on after the IC's die temperature cools down to +140C, resulting in a pulsed output under continuous thermaloverload conditions. Applications Information Setting the Output Voltage The MAX5033A/B/C have preset output voltages of 3.3V, 5.0V, and 12V, respectively. Connect FB to the preset output voltage (see the Typical Operating Circuit). The MAX5033D offers an adjustable output voltage. Set the output voltage with a resistive voltage-divider connected from the circuit's output to ground (Figure 1). Connect the center node of the divider to FB. Choose R4 less than 15k, then calculate R3 as follows: = R3 (VOUT - 1.22) x R4 1.22 VIN 7.5V TO 76V 47F R1 R2 220H VIN LX ON/OFF BST MAX5033D Boost High-Side Gate Drive (BST) Connect a flying bootstrap capacitor between LX and BST to provide the gate-drive voltage to the high-side n-channel DMOS switch. The capacitor is alternately charged from the internally regulated output-voltage VD and placed across the high-side DMOS driver. Use a 0.1F, 16V ceramic capacitor located as close to the device as possible. www.maximintegrated.com 0.1F D1 50SQ100 VOUT 5V, 0.5A COUT 33F R3 41.2k FB SGND GND VD 0.1F R4 13.3k Figure 1. Adjustable Output Voltage Maxim Integrated 9 MAX5033 500mA, 76V, High-Efficiency, MAXPower Step-Down DC-DC Converter The MAX5033 features internal compensation for optimum closed-loop bandwidth and phase margin. With the preset compensation, it is strongly advised to sense the output immediately after the primary LC. temperature rise and thermal shutdown. Use Table 1 to choose the proper rectifier at different input voltages and output current. Inductor Selection The discontinuous input-current waveform of the buck converter causes large ripple currents in the input capacitor. The switching frequency, peak inductor current, and the allowable peak-to-peak voltage ripple that reflects back to the source dictate the capacitance requirement. The MAX5033 high switching frequency allows the use of smaller-value input capacitors. The choice of an inductor is guided by the voltage difference between VIN and VOUT, the required output current, and the operating frequency of the circuit. Use an inductor with a minimum value given by: L= (VIN - VOUT ) x D 0.3 x I OUTMAX x f SW where: D = VOUT/VIN, IOUTMAX is the maximum output current required, and fSW is the operating frequency of 125kHz. Use an inductor with a maximum saturation current rating equal to at least the peak switch current limit (ILIM). Use inductors with low DC resistance for higher efficiency. Selecting a Rectifier The MAX5033 requires an external Schottky rectifier as a freewheeling diode. Connect this rectifier close to the device using short leads and short PC board traces. Choose a rectifier with a continuous current rating greater than the highest expected output current. Use a rectifier with a voltage rating greater than the maximum expected input voltage, VIN. Use a low forward-voltage Schottky rectifier for proper operation and high efficiency. Avoid higher than necessary reverse-voltage Schottky rectifiers that have higher forward-voltage drops. Use a Schottky rectifier with forward-voltage drop (VFB) less than 0.45V at +25C and maximum load current to avoid forward biasing of the internal body diode (LX to ground). Internal body-diode conduction may cause excessive junction Table 1. Diode Selection VIN (V) 7.5 to 36 7.5 to 56 7.5 to 76 DIODE PART NUMBER MANUFACTURER 15MQ040N IR B240A Diodes Incorporated B240 Central Semiconductor MBRS240, MBRS1540 ON Semiconductor 30BQ060 IR B360A Diodes Incorporated CMSH3-60 Central Semiconductor MBRD360, MBR3060 ON Semiconductor 50SQ100, 50SQ80 IR MBRM5100 Diodes Incorporated www.maximintegrated.com Input Bypass Capacitor The input ripple is comprised of VQ (caused by the capacitor discharge) and VESR (caused by the ESR of the capacitor). Use low-ESR aluminum electrolytic capacitors with high ripple-current capability at the input. Assuming that the contribution from the ESR and capacitor discharge is equal to 90% and 10%, respectively, calculate the input capacitance and the ESR required for a specified ripple using the following equations: ESR IN = C IN = VESR IL I OUT + 2 I OUT x D(1 - D) VQ x f SW where : (VIN - VOUT ) x VOUT I L = VIN x f SW x L D= VOUT VIN IOUT is the maximum output current of the converter and fSW is the oscillator switching frequency (125kHz). For example, at VIN = 48V and VOUT = 3.3V, the ESR and input capacitance are calculated for the input peak-topeak ripple of 100mV or less, yielding an ESR and capacitance value of 130m and 27F, respectively. Low-ESR, ceramic, multilayer chip capacitors are recommended for size-optimized application. For ceramic capacitors, assume the contribution from ESR and capacitor discharge is equal to 10% and 90%, respectively. The input capacitor must handle the RMS ripple current without significant rise in temperature. The maximum capacitor RMS current occurs at about 50% duty cycle. Maxim Integrated 10 MAX5033 500mA, 76V, High-Efficiency, MAXPower Step-Down DC-DC Converter Ensure that the ripple specification of the input capacitor exceeds the worst-case capacitor RMS ripple current. Use the following equations to calculate the input capacitor RMS current: = I CRMS IPRMS 2 - I AVGIN 2 where : (IPK 2 + IDC 2 + (IPK x IDC)) x D3 IPRMS= I AVGIN = VOUT x I OUT VIN x I I IPK = I OUT + L , IDC = I OUT - L 2 2 VOUT and D = VIN IPRMS is the input switch RMS current, IAVGIN is the input average current, and is the converter efficiency. The ESR of aluminum electrolytic capacitors increases significantly at cold temperatures. Use a 1F or greater value ceramic capacitor in parallel with the aluminum electrolytic input capacitor, especially for input voltages below 8V. Output Filter Capacitor The worst-case peak-to-peak and RMS capacitor ripple current, allowable peak-to-peak output ripple voltage, and the maximum deviation of the output voltage during load steps determine the capacitance and the ESR requirements for the output capacitors. The output capacitance and its ESR form a zero, which improves the closed-loop stability of the buck regulator. Choose the output capacitor so the ESR zero frequency (fZ) occurs between 20kHz to 40kHz. Use the following equation to verify the value of fZ. Capacitors with 100m to 250m ESR are recommended to ensure the closedloop stability while keeping the output ripple low. fZ = 1 2 x x C OUT x ESR OUT The output ripple is comprised of VOQ (caused by the capacitor discharge) and VOESR (caused by the ESR of the capacitor). Use low-ESR tantalum or aluminum electrolytic capacitors at the output. Assuming that the contributions from the ESR and capacitor discharge equal 80% and 20%, respectively, calculate the output capacitance and the ESR required for a specified ripple using the following equations: www.maximintegrated.com ESR OUT = C OUT VOESR IL IL 2.2 x VOQ x f SW The MAX5033 has an internal soft-start time (tSS) of 400s. It is important to keep the output rise time at startup below tSS to avoid output overshoot. The output rise time is directly proportional to the output capacitor. Use 68F or lower capacitance at the output to control the overshoot below 5%. In a dynamic load application, the allowable deviation of the output voltage during the fast-transient load dictates the output capacitance value and the ESR. The output capacitors supply the step load current until the controller responds with a greater duty cycle. The response time (tRESPONSE) depends on the closedloop bandwidth of the converter. The resistive drop across the capacitor ESR and capacitor discharge cause a voltage droop during a step load. Use a combination of low-ESR tantalum and ceramic capacitors for better transient load and ripple/noise performance. Keep the maximum outputvoltage deviation above the tolerable limits of the electronics being powered. Assuming a 50% contribution from the output capacitance discharge and the ESR drop, use the following equations to calculate the required ESR and capacitance value: VOESR ESR OUT = I STEP C OUT = I STEP x t RESPONSE VOQ where ISTEP is the load step and tRESPONSE is the response time of the controller. Controller response time is approximately one-third of the reciprocal of the closedloop unity-gain bandwidth, 20kHz (typ). PCB Layout Considerations Proper PCB layout is essential. Minimize ground noise by connecting the anode of the Schottky rectifier, the input bypass-capacitor ground lead, and the output filter-capacitor ground lead to a single point (star-ground configuration). A ground plane is required. Minimize lead lengths to reduce stray capacitance, trace resistance, and radiated noise. In particular, place the Schottky rectifier diode right next to the device. Also, place BST and VD bypass capacitors very close to the device. Use the PCB copper plane connecting to VIN and LX for heatsinking. Maxim Integrated 11 MAX5033 500mA, 76V, High-Efficiency, MAXPower Step-Down DC-DC Converter Application Circuit VIN CIN VIN BST MAX5033 R1 SGND L1 D1 VOUT COUT FB ON/OFF R2 0.1F LX GND VD 0.1F Figure 2. Fixed Output Voltages Table 2. Typical External Components Selection (Circuit of Figure 2) VIN (V) 7.5 to 76 7.5 to 76 15 to 76 VOUT (V) 3.3 5 12 www.maximintegrated.com IOUT (A) EXTERNAL COMPONENTS 0.5 CIN = 47F, Panasonic, EEVFK2A470Q COUT = 47F, Vishay Sprague, 594D476X_016C2T CBST = 0.1F, 0805 R1 = 1M 1%, 0805 R2 = 384k 1%, 0805 D1 = 50SQ100, IR L1 = 150H, Coilcraft Inc., DO5022P-154 0.5 CIN = 47F, Panasonic, EEVFK2A470Q COUT = 33F, Vishay Sprague, 594D336X_016C2T CBST = 0.1F, 0805 R1 = 1M 1%, 0805 R2 = 384k 1%, 0805 D1 = 50SQ100, IR L1 = 220H, Coilcraft Inc., DO5022P-224 0.5 CIN = 47F, Panasonic, EEVFK2A470Q COUT = 15F, Vishay Sprague, 594D156X_025C2T CBST = 0.1F, 0805 R1 = 1M 1%, 0805 R2 = 384k 1%, 0805 D1 = 50SQ100, IR L1 = 330H, Coilcraft Inc., DO5022P-334 Maxim Integrated 12 MAX5033 500mA, 76V, High-Efficiency, MAXPower Step-Down DC-DC Converter Table 2. Typical External Components Selection (Circuit of Figure 2) (continued) VIN (V) VOUT (V) 3.3 IOUT (A) 0.5 CIN = 100F, Panasonic, EEVFK1E101P COUT = 47F, Vishay Sprague, 594D476X_016C2T CBST = 0.1F, 0805 R1 = 1M 1%, 0805 R2 = 274k 1%, 0805 D1 = B220/A, Diodes Incorporated L1 = 150H, Coilcraft Inc., DO5022P-154 0.5 CIN = 100F, Panasonic, EEVFK1E101P COUT = 33F, Vishay Sprague, 594D336X_016C2T CBST = 0.1F, 0805 R1 = 1M 1%, 0805 R2 = 274k 1%, 0805 D1 = B220/A, Diodes Incorporated L1 = 220H, Coilcraft Inc., DO5022P-224 0.5 CIN = 100F, Panasonic, EEVFK1H101P COUT = 47F, Vishay Sprague, 594D476X_016C2T CBST = 0.1F, 0805 R1 = 1M 1%, 0805 R2 = 130k 1%, 0805 D1 = B240/A, Diodes Incorporated L1 = 150H, Coilcraft Inc., DO5022P-154 0.5 CIN = 100F, Panasonic, EEVFK1H101P COUT = 33F, Vishay Sprague, 594D336X_016C2T CBST = 0.1F, 0805 R1 = 1M 1%, 0805 R2 = 130k 1%, 0805 D1 = B240/A, Diodes Incorporated L1 = 220H, Coilcraft Inc., DO5022P-224 0.5 CIN = 100F, Panasonic, EEVFK1H101P COUT = 15F, Vishay Sprague, 594D156X_025C2T CBST = 0.1F, 0805 R1 = 1M 1%, 0805 R2 = 130k 1%, 0805 D1 = B240/A, Diodes Incorporated L1 = 330H, Coilcraft Inc., DO5022P-334 9 to 14 5 3.3 18 to 36 5 12 www.maximintegrated.com EXTERNAL COMPONENTS Maxim Integrated 13 MAX5033 500mA, 76V, High-Efficiency, MAXPower Step-Down DC-DC Converter Table 3. Component Suppliers PHONE FAX AVX SUPPLIER 843-946-0238 843-626-3123 www.avxcorp.com Coilcraft 847-639-6400 847-639-1469 www.coilcraft.com Diodes Incorporated 805-446-4800 805-446-4850 www.diodes.com Nichicon 858-824-1515 858-824-1525 www.nichicon.com Panasonic 714-373-7366 714-737-7323 www.panasonic.com SANYO 619-661-6835 619-661-1055 www.sanyo.com TDK 847-803-6100 847-390-4405 www.component.tdk.com Vishay 402-563-6866 402-563-6296 www.vishay.com MAX5033 PTC* ON/OFF VIN 12V VIN CIN 47F Ct Rt WEBSITE FB BST 0.1F L1 220H LX SGND GND VD 0.1F D1 B240 VOUT 5V AT 0.5A COUT 33F *LOCATE PTC AS CLOSE TO HEAT-DISSIPATING COMPONENTS AS POSSIBLE. Figure 3. Load Temperature Monitoring with ON/OFF (Requires Accurate VIN) www.maximintegrated.com Maxim Integrated 14 MAX5033 500mA, 76V, High-Efficiency, MAXPower Step-Down DC-DC Converter MAX5033B R1 ON/OFF VIN 7.5V TO 36V BST 0.1F VIN CIN 47F Ct Rt FB L1 220H LX VD SGND GND VOUT 5V AT 0.5A COUT 68F D1 B240 0.1F MAX5033A FB R1' ON/OFF VIN C'IN 68F Ct' Rt' BST 0.1F L1' 150H LX SGND GND VD V'OUT 3.3V AT 0.5A D1' B240 C'OUT 68F 0.1F Figure 4. Dual-Sequenced DC-DC Converters (Startup Delay Determined by R1/R1', Ct/Ct' and Rt/Rt') Chip Information PROCESS: BiCMOS www.maximintegrated.com Maxim Integrated 15 MAX5033 500mA, 76V, High-Efficiency, MAXPower Step-Down DC-DC Converter Package Information For the latest package outline information and land patterns (footprints), go to www.maximintegrated.com/packages. Note that a "+", "#", or "-" in the package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing pertains to the package regardless of RoHS status. PACKAGE TYPE PACKAGE CODE OUTLINE NO. LAND PATTERN NO. 8 PDIP P8+3 21-0043 -- 8 SO S8+5 21-0041 90-0096 www.maximintegrated.com Maxim Integrated 16 MAX5033 500mA, 76V, High-Efficiency, MAXPower Step-Down DC-DC Converter Revision History REVISION NUMBER REVISION DATE PAGES CHANGED 0 9/03 Initial release 1 5/04 New product update 1-7, 10 2 6/04 Removed future product asterisk and made specification changes 1, 2, 3 3 1/07 Modified Absolute Maximum Ratings specifications 4 4/10 Corrected inconsistencies in Absolute Maximum Ratings and Electrical Characteristics table 5 4/14 No /V OPNs; removed Automotive reference in Applications section DESCRIPTION -- 2 1, 2, 3, 4, 17 1 For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxim Integrated's website at www.maximintegrated.com. Maxim Integrated cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim Integrated product. No circuit patent licenses are implied. Maxim Integrated reserves the right to change the circuitry and specifications without notice at any time. The parametric values (min and max limits) shown in the Electrical Characteristics table are guaranteed. Other parametric values quoted in this data sheet are provided for guidance. Maxim Integrated and the Maxim Integrated logo are trademarks of Maxim Integrated Products, Inc. (c) 2014 Maxim Integrated Products, Inc. 17 Mouser Electronics Authorized Distributor Click to View Pricing, Inventory, Delivery & Lifecycle Information: Maxim Integrated: MAX5033DASA+ MAX5033AASA+ MAX5033AASA+T MAX5033AUPA+ MAX5033AUSA+ MAX5033AUSA+T MAX5033BASA+ MAX5033BASA+T MAX5033BUPA+ MAX5033BUSA+ MAX5033BUSA+T MAX5033DASA+T MAX5033DUPA+ MAX5033DUSA+ MAX5033DUSA+T MAX5033BASA MAX5033BASA-T MAX5033BUSA MAX5033BUSA-T