UC1730 UC2730 UC3730 Thermal Monitor FEATURES DESCRIPTION • On-Chip Temperature Transducer • Temperature Comparator Gives Threshold Temperature Alarm • Power Reference Permits Airflow Diagnostics • Precision 2.5V Power Reference Permits Airflow Diagnostics The UC1730 family of integrated circuit devices are designed to be used in a number of thermal monitoring applications. Each IC combines a temperature transducer, precision reference, and temperature comparator allowing the device to respond with a logic output if temperatures exceed a user programmed level. The reference on these devices is capable of supplying in excess of 250mA of output current − by setting a level of power dissipation the rise in die temperature will vary with airflow past the package, allowing the IC to respond to airflow conditions • Transducer Output is Easily Scaled for Increased Sensitivity • Low 2.5mA Quiescent Current BLOCK DIAGRAM These devices come in an 8-Pin DIP, plastic or ceramic, a 5-Pin TO-220 or a PLCC-20 version. In the 8-Pin version, a PTAT (proportional to absolute temperature) output reports die temperature directly. This output is configured such that its output level can be easily scaled up with two external gain resistors. A second PTAT source is internally referenced to the temperature comparator. The other input to this comparator can then be externally programmed to set a temperature threshold. When this temperature threshold is exceeded an alarm delay output is activated. Following the activation of the delay output, a separate open collector output is turned on. The delay pin can be programmed with an external RC to provide a time separation between activation of the delay pin and the alarm pin, permitting shutdown diagnostics in applications where the open collector outputs of multiple parts are wire OR’ed together. The 5-Pin version in the TO-220 package is well suited for monitoring heatsink temperatures. Enhanced airflow sensitivities can be obtained with this package by mounting the device to a small heatsink in the airstream. This version of the device does not include the PTAT output or the open collector alarm output. Pin numbers shown for 8-Pin DIP, ( ) number for 5-Pin TO-220. 10/94 UC1730 UC2730 UC3730 ABSOLUTE MAXIMUM RATINGS T, 5-Pin Plastic DIP TO-220 . . . . . . . . . . . . . . . . . . . . 65°C/W Thermal Resistance Junction to Case N, 8-Pin Plastic DIP. . . . . . . . . . . . . . . . . . . . . . . . . . . 60°C/W J, 8-Pin Ceramic DIP. . . . . . . . . . . . . . . . . . . . . . . . . . 40°C/W T, 5-Pin Plastic TO-220 . . . . . . . . . . . . . . . . . . . . . . . . . 5°C/W Operating Junction Temperature . . . . . . . . . -55°C to +150°C Storage Temperature . . . . . . . . . . . . . . . . . . -65°C to +150°C Lead Temperature (Soldering, 10 Seconds). . . . . . . . . 300°C Note 1: Voltages are referenced to ground. Currents are positive into, negative out of, the specified terminals. Note 2: Consult Packaging section of Databook for thermal limitations and considerations of package. Input Supply Voltage, (+VIN). . . . . . . . . . . . . . . . . . . . . . . 40V Alarm Output Voltage (8-Pin Version Only) . . . . . . . . . . . 40V Alarm Delay Voltage. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10V Alarm Threshold Set Voltage . . . . . . . . . . . . . . . . . . . . . . 10V 2.5V Reference Output Current . . . . . . . . . . . . . . . . . -400 mA Alarm Output Current (8-Pin Version Only) . . . . . . . . . . 0 mA Power Dissipation at TA = 25°C (Note 2) . . . . . . . . . 1000 mW Power Dissipation at TC = 25°C (Note 2) . . . . . . . . . 2000 mW Thermal Resistance Junction to Ambient N, 8-Pin Plastic DIP . . . . . . . . . . . . . . . . . . . . . . . . . 110°C/W J, 8-Pin Ceramic DIP . . . . . . . . . . . . . . . . . . . . . . . . 110°C/W CONNECTION DIAGRAMS DIL-8 (TOP VIEW) N or J Package PLCC-20 (TOP VIEW) Q Package PACKAGE PIN FUNCTION 5-PIN TO-220 (TOP VIEW) T Package FUNCTION PIN N/C ALARM DELAY ALARM OUTPUT +VIN GND N/C PTAT+ PTAT2.5V REFERENCE 2.5V REFERENCE ALARM THRESHOLD SET N/C 1-3 4 5 6 7 8-13 14 15 16 17 18 19-20 ELECTRICAL CHARACTERISTICS: Unless otherwise stated, these specifications apply for TJ = 0°C to +100°C for the UC3730, -25°C to + 100°C for the UC2730 and -55°C to +125°C for the UC1730, +VIN = + 5V, and PTAT– = 0V. TA = TJ. PARAMETERS INPUT SUPPLY Supply Current TEST CONDITIONS MIN TYP MAX UNITS +VIN = 35V 2.8 4.0 mA +VIN = 5V 2.3 3.5 mA 2.5 2.525 V REFERENCE Output Voltage TJ = 25°C 2.475 2.46 Load Regulation Over Temperature IOUT = 0 to 250mA Line Regulation +VIN = 5 to 25V 2.54 V 8.0 25 mV 1.0 5.0 mV 1.50 1.525 V 10 °C 0.005 0.02 %/V 3.0 2.0 8.0 5.0 15 °C mV TEMPERATURE COMPARATOR Temperature Comparator Threshold at 300°K (26.85°C), Nominally 5mV/°K, VINPUT High to Low Temperature Error 1.475 -10 Threshold Line Regulation +VIN = 5 to 25V Temperature Linearity Threshold Hysteresis Note 2 Input Bias Current VINPUT at 1.5V -0.5 -0.1 µA Max Output Current VOUT = 1V 1.2 3.0 mA Output Sat Voltage IOUT = 100µA 0.05 2 0.25 V UC1730 UC2730 UC3730 Unless otherwise stated, these specifications apply for TJ = 0°C to +100°C for the UC3730, ELECTRICAL CHARACTERISTICS (cont): -25°C to + 100°C for the UC2730 and -55°C to +125°C for the UC1730, +VIN = + 5V, and PTAT– = 0V. TA = TJ. PARAMETERS TEMPERATURE COMPARATOR (cont.) Output Leakage Current TEST CONDITIONS MIN TYP MAX UNIT 0.01 1.0 µA 1.460 1.50 1.54 V 14.6 -12 15 15.4 12 V °C VOUT = 1V PTAT BUFFER (8-Pin N, or J Version Only) Output Voltage at 300°K (26.85°C), Nominally 5mV/°K In 10X Config. + VIN = 25V Temperature Error Temperature Linearity (Note 2) Line Regulation Load Regulation Dropout Voltage 2.0 5.0 °C +VIN = 5 to 25V 0.02 0.04 %/V IOUT = 0 to 2mA PTAT + TO +VIN 1.0 3.0 mV 1.9 2.5 Input Bias Current at PTAT– Input V µA -3.0 -1.0 1.1 Threshold Hysteresis Voltage Input Bias Current Alarm Delay Input Low to High Alarm Delay Voltage > VTH Alarm Delay Voltage < VTH 1.2 100 0.1 1.3 250 0.5 V mV µA Max Output Current VOUT = 1V 7.0 Output Sat Voltage IOUT = 3mA 15 0.25 0.45 mA V 0.1 2.0 µA ALARM BUFFER COMPARATOR (8-Pin N, or J Version Only) Threshold Voltage (VTH) Output Leakage VOUT = 35V Note 2: This parameter is guaranteed by design and is not tested in production. APPLICATIONS AND OPERATION INFORMATION Scaling the PTAT Output (8 Pin Version Only) R2 VOUT = 5 x 1+ mV ⁄ ° K R1 (Recommended Range for R1 is 2k to 4k) VREF Maximum Output Current vs Input Supply Junction Temperature Rise vs Airflow UC3730N (8Pin Plastic Dip) 3 UC1730 UC2730 UC3730 APPLICATIONS AND OPERATION INFORMATION (Cont.) Setting a Temperature Threshold Temperature Threshold (°C) 2.5V R2 =( − 273.15 )x 0.005 R1+R2 Note:For airflow monitoring a power dissipation level can be set with a resistive load, RL, on the reference output. PD = (+ VIN - 2.5V)2/RL. Dual Speed Fan Control 2.5V R2 x − 273.15 0.005 R1+R2 2.5V RX TL(°C) = x − 273.15 0.005 R1+RX R3 Where: RX = R2 × R2 + R3 TH(°C) = UNITRODE INTEGRATED CIRCUITS 7 CONTINENTAL BLVD. • MERRIMACK, NH 03054 TEL. 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