MAX1937/MAX1938/MAX1939 19-2498 Rev 1 10/02 Two-Phase Desktop CPU Core Supply Controllers with Controlled VID Change General Description Features The MAX1937/MAX1938/MAX1939 comprise a family of 0.75% Output Voltage Accuracy synchronous, two-phase, step-down controllers capable Instant Load-Transient Response of delivering load currents up to 60A. The controllers uti- Up to 90% Efficiency Eliminates Heatsinks lize Quick-PWM control architecture in conjunction with Up to 60A Output Current active load-current voltage positioning. Quick-PWM con- 8V to 24V Input Range trol provides instantaneous load-step response, while User-Programmable Voltage Positioning programmable voltage positioning allows the converter to utilize full transient regulation limits, reducing the out- Controlled VID Voltage Transition put capacitance requirement. The two phases operate 500kHz Effective Switching Frequency 180 out-of-phase with an effective 500kHz switching fre- MAX1937: AMD Hammer Compatible quency, thus reducing input and output current ripple, as MAX1938: Intel VRM 9.0/9.1 Compatible well as reducing input filter capacitor requirements. MAX1939: AMD Athlon Mobile Compatible The MAX1937/MAX1938/MAX1939 are compliant with Soft-Start AMD Hammer, Intel Voltage-Regulator Module (VRM) Power-Good (PWRGD) Output 9.0/9.1, and AMD Athlon Mobile VID code specifica- tions (see Table 1 for VID codes). The internal DAC pro- Cycle-by-Cycle Current Limit vides ultra-high accuracy of 0.75%. A controlled VID Output Overvoltage Protection (OVP) voltage transition is implemented to minimize both R or R Current Sensing DS(ON) SENSE undervoltage and overvoltage overshoot during VID Remote Voltage Sensing input change. 28-Pin QSOP Package Remote sensing is available for high output-voltage accuracy. The MOSFET switches are driven by a 6V Ordering Information gate-drive circuit to minimize switching and crossover conduction losses to achieve efficiency as high as PART TEMP RANGE PIN-PACKAGE 90%. The MAX1937/MAX1938/MAX1939 feature cycle- MAX1937EEI -40C to +85C 28 QSOP by-cycle current limit to ensure that the current limit is MAX1938 EEI -40 C to +85C 28 QSOP not exceeded. Crowbar protection is available to pro- tect against output overvoltage. MAX1939 EEI -40 C to +85C 28 QSOP Applications Notebook and Desktop Computers Pin Configuration Servers and Workstations Blade Servers TOP VIEW VID0 1 28 V CC High-End Switches VID1 2 27 BST1 High-End Routers TIME 3 26 DH1 Macro Base Stations VID2 4 25 LX1 VID3 5 24 CS1 MAX1937 VID4 6 23 DL1 MAX1938 MAX1939 VPOS 7 22 VLG V 8 21 PGND DD ILIM 9 20 DL2 Typical Application Circuits and Functional Diagram appear GND 10 19 CS2 at end of data sheet. GNDS 11 18 LX2 REF 12 17 DH2 EN 13 16 BST2 Quick-PWM is a trademark of Maxim Integrated Products, Inc. FB 14 15 PWRGD Athlon is a trademark of Advanced Micro Devices, Inc. Intel is a registered trademark of Intel Corp. QSOP 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. EVALUATION KIT AVAILABLETwo-Phase Desktop CPU Core Supply Controllers with Controlled VID Change ABSOLUTE MAXIMUM RATINGS V to GND............................................................-0.3V to +28V DH1 to LX1.................................................-0.3V to V + 0.3V CC BST1 V , PWRGD, ILIM, FB to GND ...............................-0.3V to +6V DH2 to LX2.................................................-0.3V to V + 0.3V DD BST2 EN, GNDS, VPOS, REF, VID , DL1, DL2 to PGND ......................................-0.3V to V + 0.3V VLG TIME to GND ............................................0.3V to V + 0.3V Continuous Power Dissipation (T = +70C) VDD A PGND to GND .......................................................-0.3V to +0.3V 28-Pin QSOP (derate 20.8mW/C above +70C)......860.2mW CS1, CS2 to GND......................................................-2V to +28V Operating Temperature Range ...........................-40C to +85C VLG to GND..............................................................-0.3V to +7V Junction Temperature......................................................+150C BST1, BST2 to GND ...............................................-0.3V to +35V Storage Temperature Range .............................-65C to +150C LX1 to BST1..............................................................-7V to +0.3V Lead Temperature (soldering, 10s) .................................+300C LX2 to BST2..............................................................-7V to +0.3V 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 = 12V, V = V = 5V, PGND = GNDS = GND = 0, VID = GND, C = 47pF, C = 0.1F, V = 1V, T = 0C to CC EN VDD VPOS REF ILIM A +85C, unless otherwise noted. Typical values are at T = +25C.) A PARAMETER CONDITIONS MIN TYP MAX UNITS GENERAL MAX1937 6 24 V Operating Range V CC MAX1938/MAX1939 8 24 V Operating Range 4.5 5 5.5 V DD VLG Operating Range V > V 4.5 6.5 V VLG VDD V Operating Supply Current FB above threshold (no switching) 20 40 A CC V Operating Supply Current FB above threshold (no switching) 1.4 2.5 mA DD VLG Operating Supply Current FB above threshold (no switching) 20 60 A V Shutdown Current EN = GND <1 5 A CC V Shutdown Current EN = GND, VID not connected 50 100 A DD VLG Shutdown Current EN = GND <1 5 A TIME Output Voltage 1.96 2.00 2.04 V ILIM Input Bias V = 1.5V -250 +250 nA ILIM CS = GND, VPOS connected to REF through a 75k VPOS Output Voltage 1.96 2.0 2.04 V resistor REFERENCE Reference Voltage -50A I 50A 1.987 2.000 2.013 V REF SOFT-START MAX1937 1.1 5.5 Ramp Period MAX1938 1.5 6.2 ms MAX1939 1.3 6.5 Soft-Start Voltage Step 25 mV ERROR AMPLIFIER FB Input Resistance Resistance from FB to GND 180 k GNDS Input Bias Current -5 +5 A Output Regulation Voltage -0.75 +0.75 % Accuracy 2 MAX1937/MAX1938/MAX1939