EVALUATION KIT AVAILABLE MAX16936/MAX16938 36V, 220kHz to 2.2MHz Step-Down Converters with 28A Quiescent Current General Description Benefits and Features The MAX16936/MAX16938 are 2.5A current-mode step- Integration and High-Switching Frequency Saves down converters with integrated high-side and low-side Space MOSFETs designed to operate with an external Schottky Integrated 2.5A High-Side Switch diode for better efficiency. The low-side MOSFET enables Low-BOM-Count Current-Mode Control fixed-frequency forced-PWM (FPWM) operation under Architecture Fixed Output Voltage with 2% Accuracy (5V/3.3V) light-load applications. The devices operate with input voltages from 3.5V to 36V, while using only 28A or Externally Resistor Adjustable (1V to 10V) 220kHz to 2.2MHz Switching Frequency with quiescent current at no load. The switching frequency is resistor programmable from 220kHz to 2.2MHz and can Three Operation Modes (Skip Mode, Forced Fixed-Frequency Operation, and External be synchronized to an external clock. The devices output Frequency Synchronization) voltage is available as 5V/3.3V fixed or adjustable from Automatic LX Slew-Rate Adjustment for Optimum 1V to 10V. The wide input voltage range along with its Efficiency Across Operating Frequency Range ability to operate at 98% duty cycle during undervoltage transients make the devices ideal for automotive and 180 Out-of-Phase Clock Output at SYNCOUT industrial applications. Enables Cascaded Power Supplies for Increased Power Output Under light-load applications, the FSYNC logic input allows the devices to either operate in skip mode for Spread-Spectrum Frequency Modulation Reduces reduced current consumption or fixed-frequency FPWM EMI Emissions mode to eliminate frequency variation to minimize EMI. Wide Input Voltage Range Supports Automotive Fixed-frequency FPWM mode is extremely useful for Applications power supplies designed for RF transceivers where 3.5V to 36V Input Voltage Range tight emission control is necessary. Protection features Enable Input Compatible from 3.3V Logic Level include cycle-by-cycle current limit and thermal shutdown to 42V with automatic recovery. Additional features include a Robust Performance Supports Wide Range of power-good monitor to ease power-supply sequencing Automotive Applications and a 180 out-of-phase clock output relative to the inter- 42V Load-Dump Protection nal oscillator at SYNCOUT to create cascaded power -40C to +125C Automotive Temperature Range supplies with multiple devices. Thermal-Shutdown Protection The MAX16936/MAX16938 operate over the -40C to AEC-Q100 Qualified +125C automotive temperature range and are available Power-Good Output Allows Power-Supply in 16-pin TSSOP-EP and 5mm x 5mm, 16-pin TQFN-EP Sequencing packages. Tight Overvoltage Protection Provides Smaller Applications Overshoot Voltages (MAX16938) Point-of-Load Applications Distributed DC Power Systems Navigation and Radio Head Units Ordering Information/Selector Guide and Typical Application Circuit appear at end of data sheet. 19-6626 Rev 18 3/18MAX16936/MAX16938 36V, 220kHz to 2.2MHz Step-Down Converters with 28A Quiescent Current Absolute Maximum Ratings SUP, SUPSW, EN to PGND ...................................-0.3V to +42V Output Short-Circuit Duration ....................................Continuous LX (Note 1) ............................................................-0.3V to +42V Continuous Power Dissipation (T = +70NC)* A SUP to SUPSW .....................................................-0.3V to +0.3V TSSOP (derate 26.1mw/NC above +70NC) .............2088.8mW BIAS to AGND .........................................................-0.3V to +6V TQFN (derate 28.6mw/NC above +70NC) ...............2285.7mW SYNCOUT, FOSC, COMP, FSYNC, Operating Temperature Range ........................ -40NC to +125NC PGOOD, FB to AGND ........................-0.3V to (V + 0.3V) Junction Temperature .....................................................+150NC BIAS OUT to PGND ........................................................-0.3V to +12V Storage Temperature Range ............................ -65NC to +150NC BST to LX (Note 1) ..................................................-0.3V to +6V Lead Temperature (soldering, 10s) ................................+300NC AGND to PGND ...................................................-0.3V to + 0.3V Soldering Temperature (reflow) ......................................+260NC LX Continuous RMS Current ...................................................3A *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 opera- tion 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 2) TSSOP TQFN N Junction-to-Ambient Thermal Resistance (B ) .......38.3NC/W Junction-to-Ambient Thermal Resistance (B ) ..........35 C/W JA JA Junction-to-Case Thermal Resistance (B ) .................3NC/W Junction-to-Case Thermal Resistance (B ) ..............2.7NC/W JC JC Note 1: Self-protected against transient voltages exceeding these limits for 50ns under normal operation and loads up to the maximum rated output current. Note 2: 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, V = 14V, L1 = 2.2FH, C = 4.7FF, C = 22FF, C = 1FF, C = 0.1FF, R = 12kI, SUP SUPSW EN IN OUT BIAS BST FOSC T = T = -40NC to +125NC, unless otherwise noted. Typical values are at T = +25NC.) A J A PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS Supply Voltage V , V 3.5 36 V SUP SUPSW Load Dump Event Supply V t < 1s 42 V SUP LD LD Voltage Standby mode, no load, V = 5V, OUT 28 40 V = 0V FSYNC Supply Current I FA SUP STANDBY Standby mode, no load, V = 3.3V, OUT 22 35 V = 0V FSYNC Shutdown Supply Current I V = 0V 5 8 FA SHDN EN V = V = 6V to 42V, SUP SUPSW BIAS Regulator Voltage V 4.7 5 5.4 V BIAS I = 0 to 10mA BIAS BIAS Undervoltage Lockout V V rising 2.95 3.15 3.40 V UVBIAS BIAS BIAS Undervoltage-Lockout 450 650 mV Hysteresis Thermal Shutdown Threshold +175 NC Thermal Shutdown Threshold 15 NC Hysteresis Maxim Integrated 2 www.maximintegrated.com