MAX17031 19-4305 Rev 0 10/08 Dual Quick-PWM Step-Down Controller with Low- Power LDO and RTC Regulator for MAIN Supplies General Description Features The MAX17031 is a dual Quick-PWM step-down Dual Quick-PWM power-supply (SMPS) controller with synchronous recti- Preset 5V and 3.3V Outputs fication, intended for main 5V/3.3V power generation in Internal 100mA, 5V Linear Regulator battery-powered systems. Low-side MOSFET sensing provides a simple low-cost, highly efficient current Internal OUT1 LDO5 Bypass Switch sense for valley current-limit protection. Combined with Secondary Feedback (SKIP Input) Maintains the output overvoltage and undervoltage protection fea- Charge Pump tures, this current limit ensures robust output supplies. 3.3V, 5mA Real-Time Clock (RTC) Power (Always The 5V/3.3V SMPS outputs can save power by operat- On) ing in pulse-skipping mode or in ultrasonic mode to 2V 1% 50A Reference avoid audible noise. Ultrasonic mode forces the con- troller to maintain switching frequencies greater than 6V to 24V Input Range 20kHz at light loads. The SKIP input also has an accu- Pulse-Skipping/Forced-PWM/Ultrasonic Mode rate logic threshold, allowing it to be used as a sec- Control ondary feedback input to refresh an external charge Independent SMPS and LDO5 Enable Controls pump or secondary winding without overcharging the output voltages. Combined SMPS PGOOD Outputs An internal 100mA linear regulator generates the 5V Minimal Component Count bias needed for power-up or other low-power always- on suspend supplies. An internal bypass circuitry Ordering Information allows automatic bypassing of the linear regulator when PART TEMP RANGE PIN-PACKAGE the 5V SMPS is active. MAX17031ETG+ -40C to +85C 24 TQFN-EP* The device includes independent shutdown controls with well-defined logic thresholds to simplify power-up +Denotes a lead-free/RoHS-compliant package. and power-down sequencing. To prevent current *EP = Exposed pad. surges at startup, the internal voltage target is slowly ramped up from zero to the final target over a 1ms peri- Pin Configuration od. To prevent the output from ringing below ground in shutdown, the internal voltage target is ramped down TOP VIEW from its previous value to zero over a 1ms period. A combined power-good (PGOOD) output simplifies the 18 17 16 15 14 13 interface with external controllers. The MAX17031 is available in a 24-pin thin QFN (4mm x 4mm) package. 12 LX2 19 LX1 DH2 20 11 DH1 Applications ON1 ON2 21 10 Notebook Computers MAX17031 Ultra-Mobile PC 9 SKIP 22 PGOOD Main System Supply (5V and 3.3V Supplies) OUT2 23 8 ILIM1 *EP + 2 to 4 Li+ Cells Battery-Powered Devices ILIM2 24 7 OUT1 Telecommunication 12 3 45 6 THIN QFN 4mm 4mm *EXPOSED PAD. Quick-PWM 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 Maxims website at www.maxim-ic.com. EVALUATION KIT AVAILABLE BST2 REF ONLDO DL2 V GND CC RTC V DD IN DL1 LDO5 BST1Dual Quick-PWM Step-Down Controller with Low- Power LDO and RTC Regulator for MAIN Supplies ABSOLUTE MAXIMUM RATINGS IN to GND...............................................................-0.3V to +28V DH2 to LX2 ..............................................-0.3V to (V + 0.3V) BST2 V , V to GND .....................................................-0.3V to +6V BST2 to LX2..............................................................-0.3V to +6V DD CC RTC, LDO5, ONLDO to GND ...................................-0.3V to +6V LDO5, RTC, REF Short Circuit to GND.......................Momentary OUT2 to GND ...........................................................-0.3V to +6V RTC Current Continuous.....................................................+5mA ON1, ON2, PGOOD to GND.....................................-0.3V to +6V LDO5 Current (Internal Regulator) Continuous ..............+100mA OUT1 to GND..........................................-0.3V to (V + 0.3V) LDO5 Current (Switched Over) Continuous ...................+200mA LDO5 SKIP to GND...............................................-0.3V to (V + 0.3V) Continuous Power Dissipation (T = +70C) CC A REF, ILIM1, ILIM2 to GND..........................-0.3V to (V + 0.3V) 24-Pin, 4mm x 4mm Thin QFN (T2444-3) CC DL to GND ................................................-0.3V to (V + 0.3V) (derate 27.8mW/C above +70C).................................2.22W DD BST to GND ..........................................................-0.3V to +36V Operating Temperature Range ...........................-40C to +85C BST to V ............................................................-0.3V to +30V Junction Temperature......................................................+150C DD DH1 to LX1 ..............................................-0.3V to (V + 0.3V) Storage Temperature Range .............................-65C to +150C BST1 BST1 to LX1..............................................................-0.3V to +6V Lead Temperature (soldering, 10s) .................................+300C Note: Measurements are valid using a 20MHz bandwidth limit. 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 (Circuit of Figure 2, no load on LDO5, RTC, OUT1, OUT2, and REF, V = 12V, V = V = V = 5V, ONLDO = RTC, ON1 = ON2 IN DD CC SKIP = V , T = 0C to +85C, unless otherwise noted. Typical values are at T = +25C.) CC A A PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS INPUT SUPPLIES IN Input Voltage Range LDO5 in regulation 6 24 V V = 6V to 24V, ON1 = ON2 = GND, IN IN Standby Supply Current 85 175 A ONLDO = RTC V = 4.5V to 24V, IN IN Shutdown Supply Current 40 70 A ON1 = ON2 = ONLDO = GND ON1 = ON2 = V , V = V CC SKIP CC IN Supply Current I 0.1 0.2 mA IN V = 5.3V, V = 3.5V OUT1 OUT2 ON1 = ON2 = V , V = V CC SKIP CC V Bias Supply Current I 0.7 1.5 mA CC VCC V = 5.3V, V = 3.5V OUT1 OUT2 PWM CONTROLLERS OUT1 Output-Voltage Accuracy V V = 1.8V 4.95 5.00 5.05 V OUT1 SKIP OUT2 Output-Voltage Accuracy V V = 1.8V 3.267 3.30 3.333 V OUT2 SKIP Either SMPS, V = 1.8V, I = 0 to 5A -0.1 SKIP LOAD Load Regulation Error % Either SMPS, V = GND, I = 0 to 5A -1.7 SKIP LOAD Either SMPS, V = V , I = 0 to 5A -1.5 SKIP CC LOAD Line Regulation Error Either SMPS, IN = 6V to 28V 0.005 %/V DH1 On-Time t V = 5.0V (Note 1) 895 1052 1209 ns ON1 OUT1 DH2 On-Time t V = 3.3V (Note 1) 833 925 1017 ns ON2 OUT2 Minimum Off-Time t (Note 1) 300 400 ns OFF(MIN) Soft-Start Slew Rate t Rising/falling edge on ON1 or ON2 1 ms SS Ultrasonic Operating Frequency f V = GND 20 34 kHz SW(USONIC) SKIP 2 MAX17031