EVALUATION KIT AVAILABLE MAX17244 3.5V36V, 2.5A, Synchronous Buck Converter With 28A Quiescent Current and Reduced EMI General Description Benefits and Features The MAX17244 high-efficiency, synchronous step-down Eliminates External Components and Reduces DC-DC converter with integrated MOSFETs operates Total Cost over a 3.5V to 36V input voltage range with 42V input Integrated High-Side and Low-Side Switch Enables transient protection. The device can operate in dropout Synchronous Operation for High Efficiency and condition by running at 98% duty cycle. This converter Reduced Cost delivers up to 2.5A and generates fixed output voltages of All-Ceramic Capacitor Solution Allows Ultra- 3.3V/5V, along with the ability to program the output Compact Solution Size voltage between 1V to 10V. 220kHz to 2.2MHz Adjustable Frequency with External Synchronization The MAX17244 uses a current-mode control architecture. Power Good Output and High-Voltage EN Input The device can operate in the pulse-width modulation Simplify Power Sequencing (PWM) or pulse-frequency modulation (PFM) control schemes. PWM operation provides constant frequency Increases Design Flexibility operation at all loads, and is useful in applications sensitive 180 Out-of-Phase Clock Output at SYNCOUT to switching frequency. PFM operation disables negative Enables Cascaded Power Supplies for Increased inductor current and additionally skips pulses at light Power Output loads for high efficiency. Under light-load applications, Fixed Output Voltage with 2% Accuracy (5V/3.3V) the external sync pin FSYNC logic input allows the or Externally Resistor Adjustable (1V to 10V) device to operate either in PFM mode for reduced current Reduces Power Dissipation consumption or fixed-frequency FPWM (forced-PWM) >90% Peak Efficiency mode to eliminate frequency variation to minimize EMI. PWM and PFM Operation Optimizes Conversion Fixed-frequency FPWM mode is extremely useful for Efficiency From Heavy to Light Loads power supplies designed for RF transceivers where tight Automatic LX Slew-Rate Adjustment for Optimum emission control is necessary. Efficiency Across Operating Frequency Range This device is available in a compact 16-pin (5mm x 5mm) Low 5A (typ.) Shutdown Current TQFN package with exposed pad and 16-pin TSSOP. Low 28A (typ.) Quiescent Current -40C to +85C operation. Operates Reliably 42V Input Voltage Transient Protection Applications Fixed 8ms Internal Software Start Reduces Input Distributed Supply Regulation Inrush Current Wall Transformer Regulation Cycle-by-Cycle Current Limit, Thermal Shutdown General-Purpose Point-of-Load with Automatic Recovery Reduced EMI Emission with Spread-Spectrum Control Ordering Information and Typical Application Circuit appears at end of data sheet. 19-8526 Rev 1 3/17MAX17244 3.5V36V, 2.5A, Synchronous Buck Converter With 28A Quiescent Current and Reduced EMI Typical Application Circuit V BAT C IN2 C IN1 4.7F C IN3 R IN3 4.7F 0 C BST SUP SUPSW 0.1F BST L1 V OUT EN 2.2H 5V AT 2.5A LX OSC SYNC PULSE FSYNC C OUT V D1 OUT V 22F BIAS MAX17244 R SNUB* OUT COMP C COMP1 C SNUB* FB 1000pF R C FOSC COMP2 12k V V R 12pF OUT BIAS COMP 20k FOSC R R SYNCOUT PGOOD 100 10k BIAS PGOOD POWER-GOOD OUTPUT C BIAS 1F SYNCOUT 180 OUT-OF-PHASE OUTPUT PGND AGND *R = 1 and C = 220pF REQUIRED FOR THE FOLLOWING OPERATING CONDITIONS: SNUB SNUB V 25V, V 5V, f 1.8MHz, PWM MODE ENABLED BAT OUT SW Maxim Integrated 2 www.maximintegrated.com