EVALUATION KIT AVAILABLE MAX15046 40V, High-Performance, Synchronous Buck Controller General Description Features The MAX15046 synchronous step-down controller oper- Input Voltage Ranges from 4.5V to 40V or 5V 10% ates from a 4.5V to 40V input voltage range and gener- Adjustable Outputs from 0.85 x V Down to 0.6V IN ates an adjustable output voltage from 85% of the input Adjustable Switching Frequency (100kHz to 1MHz) voltage down to 0.6V, supporting loads up to 25A. The with 10% (1MHz) Accuracy device allows monotonic startup into a prebiased bus Adaptive Internal Digital Soft-Start without discharging the output and features adaptive internal digital soft-start. Up to 25A Output Capability The MAX15046 offers the ability to adjust the switching fre- Cycle-by-Cycle Valley-Mode Current Limit with quency from 100kHz to 1MHz with an external resistor. The Adjustable, Temperature-Compensated Threshold MAX15046s adaptive synchronous rectification eliminates (30mV to 300mV) the need for an external freewheeling Schottky diode. Monotonic Startup into Prebiased Output The device also utilizes the external low-side MOSFETs 1% Accurate Voltage Reference on-resistance as a current-sense element, eliminating the need for a current-sense resistor. This protects the DC-DC 90% Maximum Duty Cycle (MAX15046C) components from damage during output overloaded con- 3A Peak Gate Drivers ditions or output short-circuit faults without requiring a Hiccup-Mode Short-Circuit Protection current-sense resistor. Hiccup-mode current limit reduc- es power dissipation during short-circuit conditions. The Overtemperature Shutdown MAX15046 includes a power-good output and an enable Power-Good (PGOOD) Output and Enable Input input with precise turn-on/turn-off threshold, which can be (EN) with 5% Accurate Threshold used for input supply monitoring and power sequencing. Thermally Enhanced 16-Pin QSOP Package Additional protection features include sink-mode current limit and thermal shutdown. Sink-mode current limit pre- Applications vents reverse inductor current from reaching dangerous Industrial Power Supplies (PLC, Industrial Computers, levels when the device is sinking current from the output. Fieldbus Components, Fieldbus Couplers) The MAX15046A/MAX15046B feature soft-stop opera- Telecom Power Supplies tion. Soft-stop operation is disabled in the MAX15046C. Base Stations The MAX15046 is available in a 16-pin QSOP or 16-pin Ordering Information and Pin Configurations appear at end QSOP-EP package and operates over the -40C to of data sheet. +125C temperature range. Typical Operating Circuit 4.5V TO 40V V IN C1 IN CSP Q1 MAX15046 V DH CC L1 0.6V TO 0.85V x V IN PGOOD LX V OUT ON C2 C3 OFF EN BST Q2 DL LIM D1 R4 COMP DRV C4 C5 R3 R5 FB PGND C6 C7 RT GND R1 R3 R2 19-4719 Rev 3 6/14MAX15046 40V, High-Performance, Synchronous Buck Controller Absolute Maximum Ratings IN to GND ..............................................................-0.3V to +45V All Other Pins to GND .............................. -0.3V to (V + 0.3V) CC V to GND .................... -0.3V to lower of (V + 0.6V) and 6V V Short Circuit to GND .........................................Continuous CC IN CC EN, DRV to GND .....................................................-0.3V to +6V PGOOD Maximum Sink Current ........................................20mA PGOOD to GND ....................................................-0.3V to +45V Continuous Power Dissipation (T = +70C): A PGND to GND ......................................................-0.3V to +0.3V 16-Pin QSOP (derate 9.6mW/C above +70C) .......771.5mW DL to PGND ...........................................-0.3V to (V + 0.3V) 16-Pin QSOP-EP DRV BST to PGND .......................................................-0.3V to +50V (derate 22.7mW/C above +70C) .........................1818.2mW LX and CSP to PGND ..............................................-1V to +45V Operating Temperature Range ......................... -40C to +125C LX and CSP to PGND ...........................-2V (50ns max) to +45V Junction Temperature ......................................................+150C BST to LX ................................................................-0.3V to +6V Storage Temperature Range ............................ -65C to +150C CSP to LX .............................................................-0.3V to +0.3V Lead Temperature (soldering, 10s) .................................+300C DH to LX ..................................................-0.3V to (V + 0.3V) Soldering Temperature (reflow) .......................................+260C BST 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. Package Thermal Characteristics (Note 1) QSOP QSOP-EP Junction-to-Ambient Thermal Resistance ( ) .....+103.7C/W Junction-to-Ambient Thermal Resistance ( ) ..........+44C/W JA JA Junction-to-Case Thermal Resistance ( ) ...............+37C/W Junction-to-Case Thermal Resistance ( ) .................+6C/W JC JC Note 1: Package thermal resistances were obtained using the method described in JEDEC specification JESD51-7, using a four-layer board. For detailed information on package thermal considerations, refer to www.maximintegrated.com/thermal-tutorial. Electrical Characteristics (V = 24V, V = 5V, V = V = 0V, C = 1F, C = 4.7F, R = 49.9k, T = T = -40C to +125C, unless otherwise IN EN GND PGND IN VCC RT A J noted. Typical values are at T = +25C.) (Note 2) A PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS SYSTEM SPECIFICATIONS 4.5 40 Input-Voltage Range V V IN V = V = V 4.5 5.5 IN CC DRV Quiescent Supply Current I V = 24V, V = 0.9V, no switching 2 3 mA IN Q IN FB V = 24V, V = 0V, I = 0, PGOOD IN EN VCC Shutdown Supply Current I 0.35 0.55 mA IN SBY = unconnected V REGULATOR CC Output Voltage V 6V V 40V, I = 6mA 5 5.25 5.5 V CC IN LOAD V Regulator Dropout V = 4.5V, I = 25mA 0.18 0.45 V CC IN LOAD V Short-Circuit Output Current V = 5V 30 55 90 mA CC IN V Undervoltage Lockout V V rising 3.8 4 4.2 V CC CCUVLO CC V Undervoltage Lockout CC 400 mV Hysteresis ERROR AMPLIFIER (FB, COMP) FB Input-Voltage Set Point V 584 590 596 mV FB FB Input Bias Current I V = 0.6V -250 +250 nA FB FB FB to COMP Transconductance g I = 20A 600 1200 1800 S M COMP Open-Loop Gain 80 dB Unity-Gain Bandwidth Capacitor from COMP to GND = 47pF 5 MHz Maxim Integrated 2 www.maximintegrated.com