EVALUATION KIT AVAILABLE MAX16955 36V, 1MHz Step-Down Controller with Low Operating Current General Description Features Wide 3.5V to 36V Input Voltage Range The MAX16955 is a current-mode, synchronous PWM step-down controller designed to operate with input volt- 42V Input Transient Tolerance ages from 3.5V to 36V while using only 50A of quies- High Duty Cycle During Undervoltage Transients cent current at no load. The switching frequency is 220kHz to 1MHz Adjustable Switching Frequency adjustable from 220kHz to 1MHz by an external resistor Current-Mode Control Architecture and can be synchronized to an external clock up to Adjustable (1V to 10V) Output Voltage with 2% 1.1MHz. The MAX16955 output voltage is pin program- Accuracy mable to be either 5V fixed, or adjustable from 1V to 10V. The wide input voltage range, along with its ability Three Operating Modes to operate in dropout during undervoltage transients, 50A Ultra-Low Quiescent Current Skip Mode makes it ideal for automotive and industrial applications. Forced Fixed-Frequency Mode External Frequency Synchronization The MAX16955 operates in fixed-frequency PWM mode Lowest BOM Count, Current-Mode Control and low quiescent current skip mode. It features an Architecture enable logic input, which is compatible up to 42V to Power-Good Output disable the device and reduce its shutdown current to 10A. Protection features include overcurrent limit, Enable Input Compatible from 3.3V Logic Level to overvoltage, undervoltage, and thermal shutdown with 42V automatic recovery. The device also features a power- Current-Limit, Thermal Shutdown, and good monitor to ease power-supply sequencing. Overvoltage Protection The MAX16955 is available in a thermally enhanced 16- -40C to +125C Automotive Temperature Range pin TSSOP package with exposed pad and is specified Automotive Qualified for operation over the -40C to +125C automotive tem- perature range. Typical Operating Circuit Applications VBAT Automotive C IN NH Industrial C SUP DH BST COMP BST Military L LX R COMP C Point of Load COMP2 MAX16955 C COMP1 Ordering Information R SENSE DL NL PGOOD PART TEMP RANGE PIN-PACKAGE PGND EN MAX16955AUE+ -40C to +125C 16 TSSOP-EP* FSYNC CS MAX16955AUE/V+ -40C to +125C 16 TSSOP-EP* V OUT OUT FOSC 5V /V denotes an automotive qualified part. FB C OUT BIAS RFOSC +Denotes a lead(Pb)-free/RoHS-compliant package. SGND C L *EP = Exposed pad. For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxims website at www.maximintegrated.com. 19-5791 Rev 4 7/14MAX16955 36V, 1MHz Step-Down Controller with Low Operating Current ABSOLUTE MAXIMUM RATINGS SUP and EN to SGND ............................................-0.3V to +42V PGND to SGND .....................................................-0.3V to +0.3V LX to PGND ..............................................................-1V to +42V Continuous Power Dissipation (T = +70C) A BST to LX .................................................................-0.3V to +6V TSSOP (derate 26.1mW/C above +70C) .............2088.8mW* BIAS, FB, PGOOD, FSYNC to SGND .......................-0.3V to +6V Operating Temperature Range .........................-40C to +125C DH to LX ...................................................................-0.3V to +6V Junction Temperature......................................................+150C DL to PGND .............................................-0.3V to (V + 0.3V) Storage Temperature Range .............................-65C to +150C BIAS FOSC to SGND ........................................-0.3V to (V + 0.3V) Lead Temperature (soldering, 10s) .................................+300C BIAS CS and OUT to SGND............................................-0.3V to +11V Soldering Temperature (reflow) .......................................+260C *As per JEDEC51 standard (multilayer board). 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) TSSOP Junction-to-Ambient Thermal Resistance ( ) .........38.3C/W JA Junction-to-Case Thermal Resistance ( ) ...................3C/W 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 = V = 14V, C = 10F, C = 94F, C = 2.2F, C = 0.1F, R = 76.8k, T = T = -40C to +125C, unless SUP EN IN OUT BIAS BST FOSC A J otherwise noted. Typical values are at T = +25C.) (Note 2) A PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS SUP Input Voltage Range V (Note 3) 3.5 36 V SUP Fixed 5V output, fixed-frequency, PWM SUP Operating Supply Current I mode, V = V , no external FETs 1 mA SUP FB BIAS connected Skip Mode Supply Current I No load, fixed 5V output 50 90 A SKIP SUP Shutdown Supply Current I V = 0V 10 20 A SHDN,SUP EN V = 3.5V, I = 45mA 3.0 SUP BIAS BIAS Voltage V V BIAS 6V < V < 36V 4.7 5.0 5.3 SUP BIAS Undervoltage Lockout V V rising 3.1 3.4 V UVBIAS BIAS BIAS Undervoltage Lockout V falling 200 mV BIAS Hysteresis BIAS Minimum Load I V - V > 200mV 45 mA BIAS(MIN) SUP BIAS OUTPUT VOLTAGE (OUT) Output Voltage Adjustable 1.0 10 V Range OUT Pulldown Resistance R V = 0V or fault condition active 30 PULL D EN V = 6V to 36V, V = V , fixed- SUP FB BIAS Output Voltage (5V Fixed Mode) V 4.925 5.0 5.075 V OUT frequency mode (Note 4) FB Feedback Voltage V = 6V to 36V, 0V < (V - V ) SUP CS OUT V 0.99 1.0 1.01 V FB (Adjustable Mode) < 80mV, fixed-frequency mode FB Current I V = 1.0V 0.02 A FB FB Maxim Integrated 2