MAX1992/MAX1993 19-2661 Rev 1 9/05 Quick-PWM Step-Down Controllers with Inductor Saturation Protection and Dynamic Output Voltages General Description Features The MAX1992/MAX1993 pulse-width modulation (PWM) Inductor Saturation Protection controllers provide high-efficiency, excellent transient Accurate Current Limit response, and high DC output accuracy. The devices Ultra-High Efficiency step down high-voltage batteries to generate low- Quick-PWM with 100ns Load-Step Response voltage CPU core or chipset/RAM supplies in notebook computers. MAX1992 Maxims proprietary Quick-PWM quick-response, con- 1.8V/2.5V Fixed or 0.7V to 5.5V Adjustable stant on-time PWM control scheme handles wide Output Range input/output voltage ratios with ease and provides 100ns MAX1993 instant-on response to load transients, while maintaining External Reference Input a relatively constant switching frequency. Efficiency is Dynamically Selectable Output Voltage enhanced by the ability to drive very large synchronous- (0.7V to 5.5V) rectifier MOSFETs. Current sensing to ensure reliable Optional Power-Good and Fault Blanking overload and inductor saturation protection is available During Transitions using an external current-sense resistor in series with the 1% V Accuracy Over Line and Load output. Alternatively, the controller can sense the current OUT across the synchronous rectifier alone or use lossless 2V to 28V Battery Input Range (V ) IN inductor sensing for lowest power dissipation. 200/300/450/600kHz Switching Frequency Single-stage buck conversion allows the MAX1992/ Overvoltage/Undervoltage Protection Option MAX1993 to directly step down high-voltage batteries for 1.7ms Digital Soft-Start the highest possible efficiency. Alternatively, two-stage Drives Large Synchronous Rectifier FETs conversion (stepping down from another system supply rail instead of the battery) at the maximum switching fre- 2V 0.7% Reference Output quency allows the minimum possible physical size. Power-Good Window Comparator The MAX1992 powers the CPU core, chipset, DRAM, or Ordering Information other supply rails as low as 0.7V. The MAX1993 powers chipsets and graphics processor cores, which require PART TEMP RANGE PIN-PACKAGE dynamically adjustable output voltages. The MAX1993 MAX1992ETG -40C to +85C 24 Thin QFN 4mm 4mm provides a tracking input that can be used for active ter- mination buses. The MAX1992/MAX1993 are available in MAX1992ETG+ -40C to +85C 24 Thin QFN 4mm 4mm a 24-pin thin QFN package with optional overvoltage and MAX1993ETG -40C to +85C 24 Thin QFN 4mm 4mm undervoltage protection. MAX1993ETG+ -40C to +85C 24 Thin QFN 4mm 4mm For dual step-down PWM controllers with inductor satu- + Denotes lead-free package. ration protection, external reference input voltage, and dynamically selectable output voltages, refer to the Pin Configurations MAX1540/MAX1541 data sheet. TOP VIEW Applications 18 17 16 15 14 13 Notebook Computers VDD 19 CSN 12 20 11 CSP PGND Core/IO Supplies as Low as 0.7V AGND 21 10 OUT 1.8V and 2.5V Supplies MAX1992 VCC 22 9 FB DDR Memory Termination (MAX1993) N.C. SHDN 23 8 OVP/UVP 24 7 N.C Active Termination Buses (MAX1993) 12 3 4 5 6 CPU/Chipset/GPU with Dynamic Voltage Cores (MAX1993) THIN QFN 4mm x 4mm A SIGN WILL REPLACE THE FIRST PIN INDICATOR ON LEAD-FREE PACKAGES. Pin Configurations continued at end of data sheet. Quick-PWM is a trademark of Maxim Integrated Products, Inc. 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. TON DL N.C. BST LX LSAT DH PGOOD V+ ILIM SKIP REFQuick-PWM Step-Down Controllers with Inductor Saturation Protection and Dynamic Output Voltages ABSOLUTE MAXIMUM RATINGS (Note 1) V+ to AGND............................................................-0.3V to +30V LX to AGND...............................................................-2V to +30V V to AGND............................................................-0.3V to +6V BST to LX..................................................................-0.3V to +6V CC V to PGND............................................................-0.3V to +6V AGND to PGND (MAX1992 only) ..........................-0.3V to +0.3V DD PGOOD, ILIM, SKIP, SHDN to AGND ......................-0.3V to +6V REF Short Circuit to AGND.........................................Continuous REFIN, FB, CSP to AGND.........................................-0.3V to +6V Continuous Power Dissipation (T = +70C) A GATE, OD to GND (MAX1993 only) .........................-0.3V to +6V 24-Pin 4mm x 4mm Thin QFN TON, OVP/UVP, LSAT to AGND.................-0.3V to (V + 0.3V) (derated 20.8mW/C above +70C)...........................1667mW CC REF, OUT to AGND ....................................-0.3V to (V + 0.3V) Operating Temperature Range CC FBLANK to GND (MAX1993 only) ..............-0.3V to (V + 0.3V) MAX199 ETG ..................................................-40C to +85C CC DL to PGND................................................-0.3V to (V + 0.3V) Junction Temperature......................................................+150C DD CSN to AGND............................................................-2V to +30V Storage Temperature Range .............................-65C to +150C DH to LX .....................................................-0.3V to (BST + 0.3V) Lead Temperature (soldering, 10s) .................................+300C Note 1: For the MAX1993, AGND and PGND refer to a single pin designated GND. 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, V = V = SHDN = 5V, SKIP = GND, T = 0C to +85C, unless otherwise noted. Typical values are at T = +25C.) CC DD A A PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS PWM CONTROLLER V Battery voltage, V+ 2 28 IN Input Voltage Range V V V , V 4.5 5.5 BIAS CC DD MAX1992 FB = GND 2.475 2.5 2.525 Output Voltage Accuracy V+ = 4.5V to 28V, V V OUT (MAX1992 Fixed) SKIP = V CC FB = V 1.782 1.8 1.818 CC (Note 2) Feedback Voltage Accuracy MAX1992 V+ = 4.5V to 28V, SKIP = V CC V 0.693 0.7 0.707 V FB (MAX1992 Adjustable) (Note 2) MAX1993 REFIN = 0.35 REF 0.693 0.7 0.707 Feedback Voltage Accuracy V+ = 4.5V to 28V, V V FB (MAX1993) SKIP = V CC REFIN = REF 1.980 2 2.020 (Note 2) Load Regulation Error I = 0 to 3A, SKIP = V 0.1 % LOAD CC Line Regulation Error V = 4.5V to 5.5V, V+ = 4.5V to 28V 0.25 % CC FB Input Bias Current I -0.1 +0.1 A FB Output Adjust Range 0.7 5.5 V FB = GND 90 190 350 MAX1992 OUT Input Resistance R FB = V or adjustable 70 145 270 k OUT CC MAX1993 400 800 1400 OUT Discharge Mode R 10 25 DISCHARGE On-Resistance OUT Synchronous Rectifier 0.2 0.3 0.4 V Discharge Mode Turn-On Level Soft-Start Ramp Time t Rising edge on SHDN to full current limit 1.7 ms SS 2 MAX1992/MAX1993