MAX8688 19-3201 Rev 2 2/11 Digital Power-Supply Controller/Monitor with PMBus Interface General Description Features The MAX8688 fully integrated digital power-supply con- PMBus Interface for Programming, Monitoring, troller and monitor IC works with any existing POL Sequencing Up and Down, and Accurate Output- (point-of-load) power supply to provide complete digital Voltage Control programmability. By interfacing to the reference input, Controls Output Voltage with 0.2% Accuracy for feedback node, and output enable, the MAX8688 takes Line, Load, and Temperature Variations control of the POL to provide functions such as perfect Output Voltage, Output Current, and Temperature tracking, sequencing, margining, and dynamic adjust- Monitoring with Adjustable Monitor Rate ment of the output voltage. Current Measurement with 2.6% Accuracy The MAX8688 offers an accurate 12-bit analog-to-digi- tal converter (ADC) accompanied with two differential Programmable Soft-Start and Soft-Stop Ramp amplifiers for accurately monitoring both voltage and Rates current. An integrated 12-bit digital-to-analog converter Controls Up to 26 Power Supplies with Hardwired (DAC) is also available to margin power supplies as Address Pins and Up to 127 POLs with Software well as dynamically adjust the output voltage with 0.2% Addressing accuracy over temperature using this closed-loop sys- tem. An internal temperature sensor provides an addi- Compatible with REFIN and FB Terminals of POL tional level of system monitoring. Power Supplies The user-programmable registers provide flexible and Protection for POL Against Overvoltage, accurate control of time events such as a delay time Undervoltage, Overcurrent, Negative Current and and transition period, monitoring for overvoltage and Overtemperature Faults with No Action, Latch and undervoltage, overcurrent, reverse-current, overtemper- Retry (Hiccup) Options ature fault and warning handling. The closed-loop oper- Open-Drain FLT Signal for Fault Detection ation is also programmable to make sure the MAX8688 Master-Slave Clocking Option Eliminates External works with any existing POL to provide superior regula- Clock Requirement and Provides Accurate Timing tion accuracy and accurate margining. Reference The MAX8688 operates using a PMBus-compliant External EEPROM Interface for Auto-Programming communication protocol. The device is programmed on Power-Up using this protocol or simply with the use of a free graphic-user interface (GUI) available from the Maxim website that significantly reduces development time. Ordering Information Once the configuration is complete, the results can be saved into an EEPROM or loaded onto the part through PART TEMP RANGE PIN-PACKAGE the PMBus at power-up. This allows remote configura- MAX8688ALETG+ -40C to +85C 24 TQFN-EP* tion of any POL using the MAX8688, replacing expen- sive recalls or field service. Module current sharing is MAX8688AHETG+ -40C to +85C 24 TQFN-EP* also supported, since accurate current measurement MAX8688BLETG+ -40C to +85C 24 TQFN-EP* and fine resolution voltage control are available. The MAX8688BHETG+ -40C to +85C 24 TQFN-EP* MAX8688 can be programmed with up to 127 distinct +Denotes a lead(Pb)-free/RoHS-compliant package. addresses to support large systems. The MAX8688 is *EP = Exposed pad. offered in a space-saving, 24-pin, lead-free 4mm x 4mm TQFN package. Selector Guide Applications ACCURACY ENOUT POWER-UP Telecom Networking PART (%) DEFAULT STATE DC-DC Modules and POLs MAX8688ALETG+ 0.2 Low Servers MAX8688AHETG+ 0.2 High High-Reliability Infrastructure Equipment MAX8688BLETG+ 0.4 Low MAX8688BHETG+ 0.4 High PMBus is a trademark of SMIF, Inc. Pin Configuration appears at end of data sheet. 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. EVALUATION KIT AVAILABLEDigital Power-Supply Controller/Monitor with PMBus Interface ABSOLUTE MAXIMUM RATINGS AVDD, DVDD to AGND .........................................-0.3V to +4.5V SCL, SDA, CLKIO, RST to DGND .........................-0.3V to +4.5V DGND to AGND..................................................................0.3V ENOUT, FLT to DGND..............................................-0.3V to +6V RS+, RS-, ISN+, ISN- to AGND ................................-0.3V to +6V Thermal Resistance from Junction to Exposed Pad ......2.7C/W RS C, ISN C, A1/SCLE, A2/SDAE, Operating Temperature .......................................-40C to +85C A3/ONOFF to AGND............................-0.3V to (V + 0.3V) AVDD Junction Temperature......................................................+150C DACOUT to AGND .................................-0.3V to (V + 0.3V) AVDD Storage Temperature.........................................-65C to +150C REFO to AGND......................................................-0.3V to +4.5V Lead Temperature (soldering, 10s) .................................+300C Continuous Power Dissipation (T = +70C) A Soldering Temperature (reflow) (Note 1) .........................+260C 24-Pin TQFN (derate 27.8mW/C above +70C)...........2222mW* Note 1: Hand soldering not recommended. 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. PACKAGE THERMAL CHARACTERISTICS (Note 2) 24 TQFN-EP Junction-to-Ambient Thermal Resistance ( ) ............36C/W JA Junction-to-Case Thermal Resistance ( ) ................2.7C/W JC Note 2: Package thermal resistances were obtained using the method described in JEDEC specification JESD51-7, using a four- layer board. For detailed information on package thermal considerations, refer to www.maxim-ic.com/thermal-tutorial. ELECTRICAL CHARACTERISTICS (V = V = 3.3V, T = T = -40C to +85C, V - V = 2V, V = V , unless otherwise stated.) (Note 3) AVDD DVDD A J RS+ RS- RS- AGND PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS GENERAL AVDD/DVDD Operating Range 3.0 3.6 V AVDD and DVDD Operating V = V = V = V = V 6.7 8.5 mA RS+ RS- ISN+ ISN- AGND Supply Current Rising 2.70 2.8 2.95 V AVDD UVLO Hysteresis 100 mV OUTPUT-VOLTAGE SENSING MAX8688A, T = 0C to +85C, A -0.2 +0.2 V = 1V, V = 0V RS+ RS- MAX8688A, T = -40C to +85C, A -0.3 +0.3 V = 1V, V = 0V RS+ RS- Voltage Regulation Accuracy (2V % Range, Table 8) (Note 4) MAX8688B, T = 0C to +85C, A -0.4 +0.4 V = 1V, V = 0V RS+ RS- MAX8688B, T = -40C to +85C, A -0.5 +0.5 V = 1V, V = 0V RS+ RS- MAX8688A, T = 0C to +85C, A -0.3 +0.3 V = 2.5V, V = 0V RS+ RS- MAX8688A, T = -40C to +85C, A -0.4 +0.4 V = 2.5V, V = 0V RS+ RS- Voltage Regulation Accuracy (5.5V % range, Table 8) (Note 4) MAX8688B, T = 0C to +85C, A -0.4 +0.4 V = 2.5V, V = 0V RS+ RS- MAX8688B, T = -40C to +85C, A -0.5 +0.5 V = 2.5V, V = 0V RS+ RS- RS+, RS- Differential Mode Range 0 5.5 V 2 MAX8688