MAX8625A 19-1006 Rev 4 4/09 High-Efficiency, Seamless Transition, Step-Up/Down DC-DC Converter General Description Features The MAX8625A PWM step-up/down regulator is intend- Four Internal MOSFET True H-Bridge Buck/Boost ed to power digital logic, hard disk drives, motors, and Glitch-Free, Buck-Boost Transitions other loads in portable, battery-powered devices such Minimal Output Ripple Variation on Transitions as PDAs, cell phones, digital still cameras (DSCs), and MP3 players. The MAX8625A provides either a fixed Up to 92% Efficiency 3.3V or adjustable output voltage (1.25V to 4V) at up to 37A (typ) Quiescent Current in Skip Mode 0.8A from a 2.5V to 5.5V input. The MAX8625A utilizes a 2A peak current limit. 2.5V to 5.5V Input Range Maxims proprietary H-bridge topology provides a Fixed 3.3V or Adjustable Output seamless transition through all operating modes without 1A (max) Logic-Controlled Shutdown the glitches commonly seen with other devices. Four True Shutdown internal MOSFETs (two switches and two synchronous rectifiers) with internal compensation minimize external Output Overload Protection components. A SKIP input selects a low-noise, fixed- Internal Compensation frequency PWM mode, or a high-efficiency skip mode Internal Soft-Start where the converter automatically switches to PFM mode under light loads for best light-load efficiency. 1MHz Switching Frequency The internal oscillator operates at 1MHz to allow for a Thermal-Overload Protection small external inductor and capacitors. Small 3mm x 3mm, 14-Pin TDFN Package The MAX8625A features current-limit circuitry that shuts down the IC in the event of an output overload. In addi- tion, soft-start circuitry reduces inrush current during TM startup. The IC also features True Shutdown , which Ordering Information disconnects the output from the input when the IC is PIN- disabled. The MAX8625A is available in a 3mm x 3mm, PART TOP MARK PACKAGE 14-pin TDFN package. MAX8625AETD+ 14 TDFN-EP** ABQ Applications Note: The device is specified over the -40C to +85C extended PDAs and Smartphones temperature range. DSCs and Camcorders +Denotes a lead(Pb)-free/RoHS-compliant package. **EP = Exposed pad. MP3 Players and Cellular Phones Battery-Powered Hard Disk Drive (HDD) Pin Configuration Typical Operating Circuit TOP VIEW 14 13 12 11 10 9 8 OUTPUT INPUT LX1 LX2 3.3V 2.7V TO 5.5V IN OUT GND MAX8625A PWM FB MAX8625A EP + SKIP SKIP 1243 5 6 7 REF ON ON TDFN-EP OFF EP = EXPOSED PAD. True Shutdown is a trademark of Maxim Integrated Products, Inc. Maxim Integrated Products 1 For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxim s website at www.maxim-ic.com. EVALUATION KIT AVAILABLE LX1 IN LX1 IN LX2 GND LX2 GND ON OUT SKIP OUT FB REFHigh-Efficiency, Seamless Transition, Step-Up/Down DC-DC Converter ABSOLUTE MAXIMUM RATINGS IN, OUT, SKIP, ON to GND ......................................-0.3V to +6V Operating Temperature Range ...........................-40C to +85C Junction Temperature......................................................+150C REF, FB to GND.............................................-0.3V to (IN + 0.3V) LX2, LX1 (Note 1).........................................................1.5A Storage Temperature Range .............................-65C to +150C RMS Lead Temperature (soldering, 10s) .................................+300C Continuous Power Dissipation (T = +70C) A Single-Layer Board (derate 18.5mW/C above T = +70C) ...................................................1482mW A Note 1: LX1 and LX2 have internal clamp diodes to IN, GND and OUT, GND, respectively. Applications that forward bias these diodes should take care not to exceed the device s power-dissipation limits. 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 (V = 3.6V, ON = SKIP = IN, FB = GND, V = 3.3V, LX unconnected, C = C5 = 0.1F to GND, Figure 4. T = -40C to +85C. IN OUT REF A Typical values are at T = +25C, unless otherwise noted.) (Note 2) A PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS Supply Range V 2.5 5.5 V IN UVLO Threshold UVLO V rising, 60mV hysteresis 2.20 2.49 V IN Quiescent Supply Current, FPWM I No load, V = 3.2V 15 22 mA IN OUT Mode, Switching Quiescent Supply Current, Skip I SKIP = GND, no load 37 A IN Mode, Switching Quiescent Supply Current, No I SKIP = GND, FB = 1.3V 35 45 A IN Switching, Skip Mode ON = GND, T = +25C 0.1 1 A Shutdown Supply Current I A IN T = +85C 0.2 A PWM mode, V = 2.5V to 5.5V 3.30 V IN I = 0 to 0.5A, V = 2.5V to 5.5V, OUT IN -1 +1 % T = -40C to +85C (Note 3) A Output Voltage Accuracy (Fixed Output) SKIP mode, valley regulation value 3.28 V Average skip voltage 3.285 Load step +0.5A -3 % Output Voltage Range 1.25 4.00 V (Adjustable Output) Maximum Output Current V = 3.6V 0.80 A IN Soft-Start L = 3.3H C = C3 + C4 = 44F 250 mA/ms OUT Load Regulation I = 0 to 500mA 0.1 %/A OUT Line Regulation V = 2.5V to 5.5V 0.03 %/V IN OUT Bias Current I V = 3.3V 3 A OUT OUT REF Output Voltage V V = 2.5V to 5.5V 1.244 1.25 1.256 V REF IN REF Load Regulation I = 10A 1 mV REF I = 0 to full load, PWM mode V = 2.5V OUT IN FB Feedback Threshold V 1.244 1.25 1.258 V FB to 5.5V 2 MAX8625A