P (W) LOAD LT2940 Power and Current Monitor FEATURES DESCRIPTION n Four-Quadrant Power Measurement The LT 2940 measures a high side current and a differ- n 5% Power Measurement Accuracy ential voltage, multiplies them and outputs a current n 4V to 80V High Side Sense, 100V Max proportional to instantaneous power. Bidirectional high n Current Mode Power and Current Outputs side currents and bipolar voltage differences are correctly n Output Bandwidth Exceeds 500kHz handled by the four-quadrant multiplier and push-pull n 3% Current Measurement Accuracy output stage, which allows the LT2940 to indicate forward n 6V to 80V Supply Range, 100V Max and reverse power ow. n Inverting and Noninverting Open-Collector An integrated comparator with inverting and noninvert- Comparator Outputs ing open-collector outputs makes the LT2940 a complete n Available in 12-Pin DFN (3mm 3mm) and 12-Lead power level monitor. In addition, an output current pro- MSOP Packages portional to the sensed high side current allows current monitoring. The current mode outputs make scaling, APPLICATIONS ltering and time integration as simple as selecting ex- n Board Level Power and Current Monitoring ternal resistors and/or capacitors. n Line Card and Server Power Monitoring L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. n Power Sense Circuit Breaker n Power Control Loops n Power/Energy Meters n Battery Charger Metering TYPICAL APPLICATION Load Monitor Alarms Above 60W Monitor Output Level and Load Power I LOAD 2.5 120 0A TO 10A 80V 6V TO 80V 30V 20m + 15V 2.0 96 2W V LOAD LOAD 10V 5V V =6V LOAD + V I I CC 1.5 LED ON 72 1k LATCH 110k + CMPOUT V LED OFF 1.0 48 LT2940 LED ON WHEN CMPOUT 60W ALARM 10.0k P > 60W LOAD 0.5 24 + CMP V PMON GND IMON 0 0 mV mV V = P 20.75 PMON LOAD V = I 100 IMON LOAD 0 2 4 6 8 10 12 14 W A 24.9K 4.99k I (A) LOAD 2940 TA01b 1 k = V 12 k = 20m P = V I 2940 TA01a I LOAD LOAD LOAD 2940f 1 V (V) PMONLT2940 ABSOLUTE MAXIMUM RATINGS (Notes 1, 2) + V , I , I , LATCH ....................................0.3V to 100V Operating Temperature Range CC + + V , V , CMP .............................................0.3V to 36V LT2940C ................................................... 0C to 70C + Voltage Sense (V V ) .........................................36V LT2940I ................................................40C to 85C + Current Sense (I I ) ............................................ 36V Storage Temperature Range ...................65C to 150C PMON, IMON (Note 3) ...... 0.3V to V + 1V, Up to 16V Lead Temperature (Soldering, 10 sec) CC CMPOUT, CMPOUT ....................................0.3V to 36V MSOP Package .................................................300C CMPOUT, CMPOUT DC Output Current ..................22mA PIN CONFIGURATION TOP VIEW TOP VIEW CMPOUT 1 12 V CC + 1 CMPOUT 12 V CC CMPOUT 2 11 I + CMPOUT 2 11 I + CMP 3 10 I + 13 CMP 3 10 I PMON 4 9 LATCH PMON 4 9 LATCH + + IMON 5 8 V IMON 5 8 V GND 6 7 V GND 6 7 V DD PACKAGE MS PACKAGE 12-LEAD (3mm s 3mm) PLASTIC DFN 12-LEAD PLASTIC MSOP T = 125C, = 135C/W T = 125C, = 43C/W JMAX JA JMAX JA EXPOSED PAD (PIN 13) PCB GND CONNECTION OPTIONAL ORDER INFORMATION LEAD FREE FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE LT2940CDD PBF LT2940CDD TRPBF LDPP 12-Lead Plastic DFN 0C to 70C LT2940IDD PBF LT2940IDD TRPBF LDPP 12-Lead Plastic DFN 40C to 85C LT2940CMS PBF LT2940CMS TRPBF 2940 12-Lead Plastic MSOP 0C to 70C LT2940IMS PBF LT2940IMS TRPBF 2940 12-Lead Plastic MSOP 40C to 85C Consult LTC Marketing for parts speci ed with wider operating temperature ranges. *The temperature grade is identi ed by a label on the shipping container. For more information on lead free part marking, go to: