MAX8505 6 m P m O x S 19-2992 Rev 1 9/10 3A, 1MHz, 1% Accurate, Internal Switch Step-Down Regulator with Power-OK General Description Features The MAX8505 step-down regulator operates from a 2.6V Saves Space4.9mm x 6mm Footprint, 1H to 5.5V input and generates an adjustable output voltage Inductor, 47F Ceramic Output Capacitor from 0.8V to 0.85 VIN at up to 3A. With a 2.6V to 5.5V Input Voltage Range bias supply, the input voltage can be as low as 2.25V. 2.6V to 5.5V The MAX8505 integrates power MOSFETs and Down to 2.25V with Bias Supply operates at 1MHz/500kHz switching frequency to provide a compact design. Current-mode pulse-width- 0.8V to 0.85 V , 3A Output IN modulated (PWM) control simplifies compensation with Ceramic or Polymer Capacitors ceramic or polymer output capacitors and provides excellent transient response. 1% Output Accuracy Over Load, Line, and Temperature The MAX8505 features 1% accurate output over load, line, and temperature variations. Adjustable soft-start is Fast Transient Response achieved with an external capacitor. During the Adjustable Soft-Start soft-start period, the voltage-regulation loop is active. This limits the voltage dip when the active devices, In-Regulation Soft-Start Limits Output-Voltage such as microprocessors or ASICs connected to the Dips at Power-On MAX8505s output, apply a sudden load current step POK Monitors Output Voltage upon passing their undervoltage thresholds. The MAX8505 features current-limit, short-circuit, and thermal-overload protection and enables a rugged design. Open-drain power-OK (POK) monitors the output voltage. Ordering Information PART TEMP RANGE PIN-PACKAGE Applications MAX8505EEE+ -40C to +85C 16 QSOP +Denotes a lead(Pb)-free/RoHS-compliant package. P/ASIC/DSP/FPGA Core and I/O Supplies Chipset Supplies Server, RAID, and Storage Systems Functional Diagram appears at end of data sheet. Network and Telecom Equipment Pin Configuration Typical Operating Circuit TOP VIEW LX 1 16 LX BST OUTPUT INPUT IN 0.8V TO LX 2.6V TO 5.5V IN 2 15 PGND 0.85 x V IN 3A LX 3 14 LX MAX8505 PGND V MAX8505 CC IN 4 13 PGND FB BST 5 12 GND COMP V 6 11 REF CC ENABLE CTL REF POK 7 10 FB POWER-OK POK GND CTL 8 9 COMP QSOP 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. Q 4 EVALUATION KIT AVAILABLE - . 9 6 m 1 m3A, 1MHz, 1% Accurate, Internal Switch Step-Down Regulator with Power-OK ABSOLUTE MAXIMUM RATINGS CTL, FB, IN, V to GND .........................................-0.3V to +6V Operating Temperature Range CC COMP, REF, POK to GND..........................-0.3V to (V + 0.3V) MAX8505EEE...................................................-40C to +85C CC BST to LX..................................................................-0.3V to +6V Storage Temperature Range .............................-65C to +150C PGND to GND .......................................................-0.3V to +0.3V Junction Temperature......................................................+150C Continuous Power Dissipation (T = +70C) Lead Temperature (soldering, 10s) .................................+300C A 16-Pin QSOP (derate 12.5mW/C above +70C).......1000mW Soldering Temperature (reflow) .......................................+260C 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 = V = V = +3.3V, V = 0.8V, V = 1.25V, C = 0.01F, T = 0C to +85C, unless otherwise noted.) IN CC CTL FB COMP REF A PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS IN AND V CC IN Voltage Range V 2.25 V V IN CC V Voltage Range V 2.6 5.5 V CC CC 10 V = 3.3V 6 IN IN Supply Current I Switching with no load mA IN V = 5.5V 10 IN 10 V = 3.3V 3 CC V Supply Current I Switching with no load mA CC CC V = 5.5V 6 CC Total Shutdown Current into IN V = V = V - V = 5.5V, V = 0V, IN CC BST LX CTL I 20 50 A SHDN and V V = 0V CC LX V rising 2.40 2.55 V Undervoltage Lockout When LX starts/stops CC CC UVLO V th Threshold switching V falling 2.2 2.35 CC REF REF Voltage V I = 0A, V = V = 2.6V to 5.5V 0.792 0.800 0.808 V REF REF IN CC REF Shutdown Resistance From REF to GND, V = 0V 13 100 CTL REF Soft-Start Current V = 0.4V 20 25 30 A REF Output from 0% to 100%, C = 0.01F to REF Soft-Start Ramp Time 32 ms/F 1F FB FB Regulation Voltage V = 2.6V to 5.5V 0.792 0.800 0.808 V IN FB Input Bias Current V = 0.7V 0.01 0.1 A FB V = V = 3.3V, V = 1.2V, IN CC OUT Maximum Output Current I 3A OUT MAX L = 1H/5.9m (Note 1) 10.5 12 13.5 FB high FB Threshold for POK Transition FB rising or falling % FB low -13.5 -12 -10.5 FB to POK Delay FB rising or falling 50 s COMP COMP Transconductance From FB to COMP 60 100 160 S Gain from FB to COMP V = 1.25V to 1.75V 80 dB COMP 2 MAX8505