NCT72 1 C Temperature Monitor with Series Resistance Cancellation The NCT72 is a dual-channel digital thermometer and undertemperature/overtemperature alarm, intended for use in PCs and www.onsemi.com thermal management systems. It is pin and register compatible with the NCT1008 but the NCT72 allows the user to pull the ALERT pin to 1.8 V without increasing the device Idd. A feature of the NCT72 is series resistance cancellation, where up to 1.5 k (typical) of resistance in series with the temperature monitoring diode can be automatically WDFN8 DFN8 cancelled from the temperature result, allowing noise filtering. The CASE 511AT CASE 506BJ NCT72 has a configurable ALERT output and an extended, switchable temperature measurement range. PIN ASSIGNMENT The NCT72 can measure the temperature of a remote thermal diode accurate to 1C and the ambient temperature accurate to 3C. The 1 8 V SCLK DD temperature measurement range defaults to 0C to +127C, compatible with the NCT1008, but it can be switched to a wider measurement range 2 7 D+ SDATA of 64C to +191C. ALERT/ 3 6 D The NCT72 communicates over a 2-wire serial interface, compatible THERM2 2 THERM 4 5 GND with system management bus (SMBus/I C) standards. The default 2 SMBus/I C address of the NCT72 is 0x4C. An NCT72D is available (Top View) 2 with an SMBus/I C address of 0x4D. This is useful if more than one 2 NCT72 is used on the same SMBus/I C. MARKING DIAGRAMS An ALERT output signals when the on-chip or remote temperature is out of range. The THERM output is a comparator output that allows 1 on/off control of a cooling fan. The ALERT output can be reconfigured 7xM as a second THERM output, if required. Features WDFN8 On-chip and Remote Temperature Sensor 7x = Device Code (Where x = C or D) 0.25C Resolution/1C Accuracy on Remote Channel M = Date Code = Pb-Free Package 1C Resolution/1C Accuracy on Local Channel Series Resistance Cancellation Up to 1.5 k (Note: Microdot may be in either location) Extended, Switchable Temperature Measurement Range 0C to +127C (Default) or 64C to +191C 1 8 Pin and Register Compatible with NCT1008 NCT 72x Remote THERM Limit of 108C ALYW 2 2-wire SMBus/I C Serial Interface with SMBus Alert Support Programmable Over/Undertemperature Limits DFN8 Offset Registers for System Calibration x = C or D Up to Two Overtemperature Fail-safe THERM Outputs A = Assembly Location Small 8-lead DFN L = Wafer Lot Y = Year 240 A Operating Current, 5 A Standby Current W = Work Week Compatible with 1.8 V Logic = Pb-Free Package These Devices are Pb-Free, Halogen Free/BFR Free and are RoHS (Note: Microdot may be in either location) Compliant Applications ORDERING INFORMATION Smart Phones See detailed ordering and shipping information in the package dimensions section on page 18 of this data sheet. Desktop and Notebook Computers Smart Batteries Semiconductor Components Industries, LLC, 2012 1 Publication Order Number: June, 2017 Rev. 5 NCT72/DNCT72 Automotive Embedded Systems CONVERSION RATE ON-CHIP ADDRESS POINTER REGISTER TEMPERATURE REGISTER SENSOR LOCAL TEMPERATURE LOCAL TEMPERATURE LOW-LIMIT REGISTER VALUE REGISTER LOCAL TEMPERATURE D+ 2 HIGH-LIMIT REGISTER ANALOG A-TO-D MUX CONVERTER D REMOTE TEMPERATURE 3 LOW-LIMIT REGISTER RUN/STANDBY BUSY REMOTE TEMPERATURE REMOTE TEMPERATURE HIGH-LIMIT REGISTER VALUE REGISTER LOCAL THERM LIMIT REGISTERS REMOTE OFFSET EXTERNAL THERM REGISTER LIMIT REGISTERS CONFIGURATION REGISTERS EXTERNAL DIODE OPEN-CIRCUIT INTERRUPT STATUS REGISTER MASKING NCT72 2 SMBus/I C INTERFACE 1 5 7 8 4 6 V GND SDATA SCLK THERM ALERT/THERM2 DD Figure 1. Functional Block Diagram Table 1. PIN ASSIGNMENT Pin No. Mnemonic Description 1 V Positive Supply, 2.8 V to 3.6 V. DD 2 D+ Positive Connection to Remote Temperature Sensor. 3 D Negative Connection to Remote Temperature Sensor. 4 THERM Open-drain Output. Can be used to turn a fan on/off or throttle a CPU clock in the event of an overtemperature condition. Requires pullup resistor. 5 GND Supply Ground Connection. 6 ALERT/THERM2 Open-drain Logic Output Used as Interrupt or SMBus ALERT. This can also be configured as a second THERM output. Requires pullup resistor. 7 SDATA Logic Input/Output, SMBus Serial Data. Open-drain Output. Requires pullup resistor. 8 SCLK Logic Input, SMBus Serial Clock. Requires pullup resistor. NOTE: The ground slug on 3x3 package can be left unconnected. www.onsemi.com 2 DIGITAL MUX LIMIT COMPARATOR DIGITAL MUX