MAX1901/MAX1902/MAX1904 19-2224 Rev 3 12/03 500kHz Multi-Output, Low-Noise Power-Supply Controllers for Notebook Computers General Description Features The MAX1901/MAX1902/MAX1904 are buck-topology, 97% Efficiency step-down, switch-mode, power-supply controllers that 4.2V to 30V Input Range generate logic-supply voltages in battery-powered sys- 2.5V to 5.5V Dual Adjustable Outputs tems. These high-performance, dual/triple-output devices Selectable 3.3V and 5V Fixed or Adjustable include on-board power-up sequencing, power-good sig- Outputs (Dual Mode) naling with delay, digital soft-start, secondary winding 12V Linear Regulator control, low dropout circuitry, internal frequency-compen- Adjustable Secondary Feedback sation networks, and automatic bootstrapping. (MAX1901/MAX1904) Up to 97% efficiency is achieved through synchronous 5V/50mA Linear Regulator Output rectification and Maxims proprietary Idle Mode control Precision 2.5V Reference Output scheme. Efficiency is greater than 80% over a 1000:1 Programmable Power-Up Sequencing load-current range, which extends battery life in system Power-Good (RESET) Output suspend or standby mode. Excellent dynamic response Output Overvoltage Protection corrects output load transients within five clock cycles. (MAX1901/MAX1902) Strong 1A on-board gate drivers ensure fast external N- Output Undervoltage Shutdown channel MOSFET switching. (MAX1901/MAX1902) These devices feature a logic-controlled and synchroniz- 333kHz/500kHz Low-Noise, Fixed-Frequency able, fixed-frequency, pulse-width modulation (PWM) Operation operating mode. This reduces noise and RF interference Low-Dropout, 98% Duty-Factor Operation in sensitive mobile communications and pen-entry appli- 2.5mW Typical Quiescent Power (12V input, both cations. Asserting the SKIP pin enables fixed-frequency SMPSs on) mode, for lowest noise under all load conditions. 4A Typical Shutdown Current The MAX1901/MAX1902/MAX1904 include two PWM reg- ulators, adjustable from 2.5V to 5.5V with fixed 5.0V and Ordering Information 3.3V modes. All these devices include secondary feed- back regulation, and the MAX1902 contains a 12V/120mA PART TEMP RANGE PIN-PACKAGE linear regulator. The MAX1901/MAX1904 include a sec- MAX1901EAI -40C to +85C 28 SSOP ondary feedback input (SECFB), plus a control pin MAX1901ETJ -40C to +85C32 Thin QFN 5m m x 5mm (STEER) that selects which PWM (3.3V or 5V) receives the secondary feedback signal. SECFB provides a method MAX1902EAI -40C to +85C 28 SSOP for adjusting the secondary winding voltage regulation MAX1902ETJ -40C to +85C32 Thin QFN 5m m x 5mm point with an external resistor divider, and is intended to MAX1904EAI -40C to +85C 28 SSOP aid in creating auxiliary voltages other than fixed 12V. MAX1904ETJ -40C to +85C32 Thin QFN 5m m x 5mm The MAX1901/MAX1902 contain internal output overvolt- age and undervoltage protection features. Functional Diagram Applications INPUT Notebook and Subnotebook Computers 5V (RTC) 12V PDAs and Mobile Communicators 5V 12V LINEAR LINEAR Desktop CPU Local DC-DC Converters 3.3V 5V 3.3V 5V SMPS SMPS Idle Mode is a trademark of Maxim Integrated Products, Inc. Dual Mode is a trademark of Maxim Integrated Products, Inc. POWER-UP POWER- ON/OFF RESET SEQUENCE GOOD Pin Configurations appear at end of data sheet. Maxim Integrated Products 1 For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct at 1-888-629-4642, or visit Maxims website at www.maxim-ic.com.500kHz Multi-Output, Low-Noise Power-Supply Controllers for Notebook Computers ABSOLUTE MAXIMUM RATINGS V+ to GND..............................................................-0.3V to +36V DH3 to LX3 ..............................................-0.3V to (BST3 + 0.3V) PGND to GND.....................................................................0.3V DH5 to LX5 ..............................................-0.3V to (BST5 + 0.3V) V to GND ................................................................-0.3V to +6V V , REF Short to GND ................................................Momentary L L BST3, BST5 to GND ..............................................-0.3V to +36V 12OUT Short to GND..................................................Continuous CSH3, CSH5 to GND................................................-0.3V to +6V REF Current...........................................................+5mA to -1mA FB3 to GND..............................................-0.3V to (CSL3 + 0.3V) V Current.........................................................................+50mA L FB5 to GND...............................................-0.3V to (CSL5 +0.3V) 12OUT Current ............................................................+200mA LX3 to BST3..............................................................-6V to +0.3V V Shunt Current............................................................+15mA DD LX5 to BST5..............................................................-6V to +0.3V Continuous Power Dissipation (T = +70C) A REF, SYNC, SEQ, STEER, SKIP, 28-Pin SSOP (derate 9.52mW/C above +70C) ......762mW TIME/ON5, SECFB, RESET to GND ........-0.3V to (V + 0.3V) 32-Pin Thin QFN (derate 21.3mW/C above +70C) ..1702mW L V to GND............................................................-0.3V to +20V Operating Temperature Range ...........................-40C to +85C DD RUN/ON3, SHDN to GND.............................-0.3V to (V+ + 0.3V) Storage Temperature Range ............................-65C to +160C 12OUT to GND ..........................................-0.3V to (V + 0.3V) Lead Temperature (soldering, 10s) ................................+300C DD DL3, DL5 to PGND........................................-0.3V to (V + 0.3V) L 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+ = 15V, both PWMs on, SYNC = V , V load = 0, REF load = 0, SKIP = 0, T = 0C to +85C, unless otherwise noted. Typical L L A values are at T = +25C.) A PARAMETER CONDITIONS MIN TYP MAX UNITS MAIN SMPS CONTROLLERS Input Voltage Range 4.2 30.0 V V+ = 4.2V to 30V, CSH3 - CSL3 = 0, 3V Output Voltage in Adjustable Mode 2.42 2.5 2.58 V CSL3 tied to FB3 V+ = 4.2V to 30V, 0 < CSH3 - CSL3 3V Output Voltage in Fixed Mode 3.20 3.39 3.47 V < 80mV, FB3 = 0 V+ = 4.2V to 30V, CSH5 - CSL5 = 0, 5V Output Voltage in Adjustable Mode 2.42 2.5 2.58 V CSL5 tied to FB5 V+ = 5.3V to 30V, 0 < CSH5 - CSL5 5V Output Voltage in Fixed Mode 4.85 5.13 5.25 V < 80mV, FB5 = 0 Output Voltage Adjust Range Either SMPS REF 5.5 V Adjustable-Mode Threshold Voltage Dual-mode comparator 0.5 1.1 V Load Regulation Either SMPS, 0 < CSH - CSL < 80mV -2 % Line Regulation Either SMPS, 5.2V < V+ < 30V 0.03 %/V CSH3 - CSL3 or CSH5 - CSL5 80 100 120 Current-Limit Threshold mV SKIP = V or V < 13V or SECFB < 2.44V -50 -100 -150 L DD Idle Mode Threshold SKIP = 0, not tested 10 25 40 mV From enable to 95% full current limit with Soft-Start Ramp Time 512 clks respect to f (Note 1) OSC SYNC = V 450 500 550 L Oscillator Frequency kHz SYNC = 0 283 333 383 2 MAX1901/MAX1902/MAX1904