TC74 Tiny Serial Digital Thermal Sensor Features General Description * * * * The TC74 is a serially accessible digital temperature sensor particularly suited for low cost and small formfactor applications. Temperature data is converted from the onboard thermal sensing element and made available as an 8-bit digital word. Digital Temperature Sensing in SOT-23-5 Package Outputs Temperature as an 8-Bit Digital Word Simple Serial Port Interface Solid-State Temperature Sensing: - 2C Accuracy from +25C to +85C - 3C Accuracy from 0C to +125C * 3.0 and 5.5V Operating Range * Low Power: - 200A Operating - 5A Standby Mode Applications * Thermal Protection for Hard Disk Drives and other PC Peripherals * PC Card Devices for Notebook Computers * Low Cost Thermostat Controls * Power Supplies * Thermistor Replacement Communication with the TC74 is accomplished via a 2wire SMBus/I2CTM compatible serial port. This bus also can be used to implement multi-drop/multi-zone monitoring. The SHDN bit in the CONFIG register can be used to activate the low power Standby mode. Temperature resolution is 1C. Conversion rate is a nominal 8 samples/sec. Power consumption is only 200A typ, (5A Standby, typ). Small size, low installed cost, and ease of use make the TC74 an ideal choice for implementing thermal management in a variety of systems. Functional Block Diagram Internal Sensor (Diode) Package Type Serial Port Interface TO-220 SDA SCL Modulator TC74 Control Logic 1 2 3 4 5 NC SDA GND SCLK VDD Temperature Register SOT-23 SDA SCLK 5 4 TC74 1 2 3 NC GND VDD 2002 Microchip Technology Inc. DS21462B-page 1 TC74 Device Selection Table Part Number Package Address Temperature Range TC74A0-3.3VCT SOT-23A-5 1001 000 -40C to +125C TC74A1-3.3VCT SOT-23A-5 1001 001 -40C to +125C TC74A2-3.3VCT SOT-23A-5 1001 010 -40C to +125C TC74A3-3.3VCT SOT-23A-5 1001 011 -40C to +125C TC74A4-3.3VCT SOT-23A-5 1001 100 -40C to +125C TC74A5-3.3VCT* SOT-23A-5 1001 101* -40C to +125c TC74A6-3.3VCT SOT-23A-5 1001 110 -40C to +125C TC74A7-3.3VCT SOT-23A-5 1001 111 -40C to +125C TC74A0-5.0VCT SOT-23A-5 1001 000 -40C to +125C TC74A1-5.0VCT SOT-23A-5 1001 001 -40C to +125C TC74A2-5.0VCT SOT-23A-5 1001 010 -40C to +125C TC74A3-5.0VCT SOT-23A-5 1001 011 -40C to +125C TC74A4-5.0VCT SOT-23A-5 1001 100 -40C to +125C TC74A5-5.0VCT* SOT-23A-5 1001 101 -40C to +125C TC74A6-5.0VCT SOT-23A-5 1001 110 -40C to +125C TC74A7-5.0VCT SOT-23A-5 1001 111 -40C to +125C TC74A0-3.3VAT TO-220-5 1001 000 -40C to +125C TC74A1-3.3VAT TO-220-5 1001 001 -40C to +125C TC74A2-3.3VAT TO-220-5 1001 010 -40C to +125C TC74A3-3.3VAT TO-220-5 1001 011 -40C to +125C TC74A4-3.3VAT TO-220-5 1001 100 -40C to +125C TC74A5-3.3VAT TO-220-5 1001 101 -40C to +125C TC74A6-3.3VAT TO-220-5 1001 110 -40C to +125C TC74A7-3.3VAT TO-220-5 1001 111 -40C to +125C TC74A0-5.0VAT TO-220-5 1001 000 -40C to +125C TC74A1-5.0VAT TO-220-5 1001 001 -40C to +125C TC74A2-5.0VAT TO-220-5 1001 010 -40C to +125C TC74A3-5.0VAT TO-220-5 1001 011 -40C to +125C TC74A4-5.0VAT TO-220-5 1001 100 -40C to +125C TC74A5-5.0VAT TO-220-5 1001 101 -40C to +125C TC74A6-5.0VAT TO-220-5 1001 110 -40C to +125C TC74A7-5.0VAT TO-220-5 1001 111 -40C to +125C NOTE: *Default Address. DS21462B-page 2 2002 Microchip Technology Inc. TC74 1.0 ELECTRICAL CHARACTERISTICS *Stresses above 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 above those indicated in the operation sections of the specifications is not implied. Exposure to Absolute Maximum Rating conditions for extended periods may affect device reliability. Absolute Maximum Ratings* Supply Voltage (V DD) ............................................ +6V Voltage On Any Pin ....... (GND - 0.3V) to (VDD + 0.3V) Current On Any Pin .......................................... 50 mA Operating Temperature (TA)........................ See Below Storage Temperature (TSTG) .............. -65C to +150C TC74 ELECTRICAL SPECIFICATIONS Electrical Characteristics: VDD = 3.3V or 5.0V (Note 5), -40C TA 125C, unless otherwise noted. Symbol Parameter Min Typ. Max Unit Test Conditions Power Supply VPOR Power-on Reset Threshold 1.2 -- 2.2 V VDD Falling Edge or Rising Edge IDD Operating Current -- 200 350 A VDD = 5.5V Serial Port Inactive (Note 1) IDD-STANDBY Standby Supply Current -- 5 10 A VDD = 3.3V Serial Port Inactive (Note 1) Temperature to Bits Converter TERR Temperature Accuracy TC74A -2 -3 -- -- +2 -- +2 C +25C