IR3720 DATA SHEET Power Monitor IC with 2 Digital I C Interface FEATURES DESCRIPTION Accurate TruePower monitor The IR3720 measures the output voltage and inductor Minimizes dynamic errors current of low-voltage DC-to-DC converters and reports the average power over a user specified time interval as Reports voltage, current, or power 2 a digital word on the I C. The output current is Digital interface 2 measured across a current sensing resistor or indirectly SMBus and I C compatible across the inductors DCR winding resistance. Programmable averaging interval Additionally, the current measurement method is also Flexible current sensing applicable to multiphase converters. Resistive or Inductor DCR Applications The real time voltage and current signals are multiplied, Synchronous rectified buck converters digitized, and averaged over a user selectable Multiphase converters averaging interval providing Patent Pending 10pin 3x3 DFN lead free package TruePower measurement of highly dynamic loads. RoHS compliant TYPICAL APPLICATION CIRCUIT 3.3V DCR Phase L Output Capacitors VO VDD LOAD R To system Single cs1 C CS1 IR3720 Controller R Phase cs2 C CS2 2 I C Bus Converter 2 V REF VCS R T GND Power Return GND ORDERING INFORMATION Device Package Order Quantity IR3720MTRPBF 10 lead DFN (3x3 mm body) 3000 piece reel * IR3720MPBF 10 lead DFN (3x3 mm body) 121 Piece tube * Samples only Page 1 of 20 www.irf.com 09/09/08 IR3720 DATA SHEET ABSOLUTE MAXIMUM RATINGS o All voltages referenced to GND Operating Junction Temperature.... -10C to 150 C o o VDD: ................................................................3.9V Storage Temperature Range.......... -65 C to 150 C ALERT :...........................................................3.9V Thermal Impedance ( )............................53C/W JC ALERT ..............................................<VDD + 0.3V ESD Rating ............HBM Class 2 JEDEC Standard EXTCLK ...........................................................3.9V MSL Rating ..................................................Level 2 All other Analog and Digital pins......................3.9V Reflow Temperature ..................................... 260C 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 are not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. ELECTRICAL SPECIFICATIONS o o Unless otherwise specified, these specifications apply: VDD = 3.3V 5%, 0 C T 125 C, 0.5 VO 1.8 V, and J operation in the system accuracy test circuit. See notes following table. PARAMETER TEST CONDITION MIN TYP MAX UNIT IC SYSTEM ACCURACY Power accuracy, R = 600 , R = 25.5 k, V = 20 mV, 3.3 % CS2 T DCR IC only VO=1 volt, C = 1 F CS2 Sampling frequency 512 kHz. O O Sampling interval 8 ms, 0 C T 85 C J Notes 1, 2 BIAS SUPPLY VDD Turn-on Threshold, VDD 3.1 V UP VDD Turn-off Threshold, VDD 2.4 V DN VDD Operating Current R = 25.5 k 480 660 T A VDD Shutdown Current Config Reg enable bit d4=1 17 100 A VOLTAGE REFERENCE V Voltage R = 25.5 k 1.4 1.5 1.6 V REF T Reference load, R Note 1 20 25.5 40 k T VOLTAGE SENSOR O O Voltage error VO=1V V =0 mV, 0 C T 85 C -0.75 0.75 % DCR J R =600 , R =25.5 k, Note 1 CS2 T Voltage, full scale V 1.854 V FS CURRENT SENSOR Voltage, Current Gain, V R = 25.5 k 1.5 V IG T Current range, Io x DCR RCS2=600 , R =25.5 k -35 35 mV T O O Current error VO=1V V =20 mV, 0 C T 85 C -2.4 2.4 % DCR J RCS2=600 , R =25.5 K, Note 1 T Page 2 of 20 www.irf.com 09/09/08