| FeaturesThe MAX1937/MAX1938/MAX1939 comprise a family of ±0.75% Output Voltage Accuracysynchronous, two-phase, step-down controllers capable Instant Load-Transient Responseof delivering load currents up to 60A. The controllers uti- Up to 90% Efficiency Eliminates Heatsinkslize Quick-PWM™ control architecture in conjunction with Up to 60A Output Currentactive load-current voltage positioning. Quick-PWM con- 8V to 24V Input Rangetrol provides instantaneous load-step response, while User-Programmable Voltage Positioningprogrammable voltage positioning allows the converterto utilize full transient regulation limits, reducing the out- Controlled VID Voltage Transitionput capacitance requirement. The two phases operate 500kHz Effective Switching Frequency180° out-of-phase with an effective 500kHz switching fre- MAX1937: AMD Hammer Compatiblequency, thus reducing input and output current ripple, as MAX1938: Intel VRM 9.0/9.1 Compatiblewell as reducing input filter capacitor requirements. MAX1939: AMD Athlon Mobile CompatibleThe MAX1937/MAX1938/MAX1939 are compliant with Soft-StartAMD Hammer, Intel ‚ Voltage-Regulator Module (VRM) Power-Good (PWRGD) Output9.0/9.1, and AMD Athlon™ Mobile VID code specifica-tions (see Table 1 for VID codes). The internal DAC pro- Cycle-by-Cycle Current Limitvides ultra-high accuracy of ±0.75%. A controlled VID Output Overvoltage Protection (OVP)voltage transition is implemented to minimize both R or R Current SensingDS(ON) SENSEundervoltage and overvoltage overshoot during VID Remote Voltage Sensinginput change. 28-Pin QSOP PackageRemote sensing is available for high output-voltageaccuracy. The MOSFET switches are driven by a 6VOrdering Informationgate-drive circuit to minimize switching and crossoverconduction losses to achieve efficiency as high asPART TEMP RANGE PIN-PACKAGE90%. The MAX1937/MAX1938/MAX1939 feature cycle- MAX1937EEI -40 °C to +85°C 28 QSOP by-cycle current limit to ensure that the current limit isnot exceeded. Crowbar protection is available to pro- MAX1938 EEI -40 °C to +85°C 28 QSOPtect against output overvoltage.MAX1939 EEI -40 °C to +85°C 28 QSOPELECTRICAL CHARACTERISTICS(V = 12V, V = V = 5V, PGND = GNDS = GND = 0, VID_ = GND, C = 47pF, C = 0.1µF, V = 1V, T = 0°C toCC EN VDD VPOS REF ILIM A+85°C, unless otherwise noted. Typical values are at T = +25°C.)APARAMETER CONDITIONS MIN TYP MAX UNITS GENERAL MAX1937 6 24 V Operating Range VCC MAX1938/MAX1939 8 24V Operating Range 4.5 5 5.5 VDD VLG Operating Range V > V 4.5 6.5 VVLG VDDV Operating Supply Current FB above threshold (no switching) 20 40 µACC V Operating Supply Current FB above threshold (no switching) 1.4 2.5 mADD VLG Operating Supply Current FB above threshold (no switching) 20 60 µAV Shutdown Current EN = GND <1 5 µA CCV Shutdown Current EN = GND, VID_ not connected 50 100 µADD VLG Shutdown Current EN = GND <1 5 µA 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 75kΩVPOS Output Voltage 1.96 2.0 2.04 Vresistor REFERENCE Reference Voltage -50µA ≤ I ≤ 50µA 1.987 2.000 2.013 VREF 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 kΩGNDS Input Bias Current -5 +5 µA Output Regulation Voltage -0.75 +0.75 %Accuracy2 _______MAX1937/MAX1938/MAX1939MAX1937/MAX1938/MAX1939Two-Phase Desktop CPU Core Supply Controllerswith Controlled VID Change |
