TC623 TELCOM | Alldatasheet
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Technical content
2-25TELCOM SEMICONDUCTOR, INC. 3V, DUAL TRIP POINT TEMPERATURE SENSOR TC623
FEATURES
n Integrated Temp Sensor and Detector Operate from a Supply Voltage as Low as 2.7V n Replaces Mechanical Thermostats and Switches n On-Chip Temperature Sense n 8-Pin DIP or SOIC for Direct PCB Mounting n 2 User-Programmable Temperature Set Points n 2 Independent Temperature Limit Outputs n Heat/Cool Regulate Output
APPLICATIONS
n System Over-or Under-Temperature Shutdown n Advanced Thermal Warning n Fan Speed Control Circuits n Accurate Appliance Temperature Sensing n Environmental Control GENERAL DESCRIPTION The TC623 is a 3V solid-state, programmable tempera- ture sensor designed for use in thermal management appli- cations. It features dual thermal interrupt outputs (LOW LIMIT and HIGH LIMIT) each of which program with a single external resistor. The HIGH LIMIT and LOW LIMIT outputs are driven active (high) when measured temperature equals the user-programmed limits. The CONTROL output is driven active (high) when temperature equals the HIGH LIMIT setpoint, and turned off when temperature falls below the LOW LIMIT setpoint. The CONTROL output can be used to provide simple ON/OFF control to a cooling fan if so desired. Low voltage operation, easy setpoint programming, small size and low cost make the TC623 an ideal choice for many thermal management applications.
ORDERING INFORMATION
Part No. Package Range TC623CCOA 8-Pin SOIC 0 °C to +70°C TC623CCPA 8-Pin Plastic DIP 0 °C to +70°C TC623CEOA 8-Pin SOIC – 40 °C to +85°C TC623CEPA 8-Pin Plastic DIP – 40 °C to +85°C TC623CVOA 8-Pin SOIC – 40 °C to +125°C FUNCTIONAL BLOCK DIAGRAM HIGH SET 2LOW SET NC GND CONTROL HIGH LIMIT VCC LOW LIMIT LATCH Q SR TC623 R < RLOW HIGH VREF GEN. VREF GEN. VREF TEMP TO VOLTAGE CONVERTER GND HIGH SET LOW SET NC GND HIGH SET LOW SET NC VCC HIGH LIMIT CONTROL LOW LIMIT VCC HIGH LIMIT CONTROL LOW LIMIT 1 8 2 7 3 6 4 5 TC623CCOA TC623CEOA TC623CVOA TC623CCPA TC623CEPA PIN CONFIGURATION (DIP and SOIC) NOTE: Latch Q Output, ("C" Option), is a Standard Device. Contact Factory for Latch Q Output, ("H" Option). TC623-5 9/18/96
2-27TELCOM SEMICONDUCTOR, INC. To prevent output "chattering" when measured tem- perature is at (or near) the programmed trip point values, the LOW SET and HIGH SET inputs each have a built-in hysteresis of – 2°C max. As a result, the HIGH LIMIT and LOW LIMIT outputs remain active until the measured tem- perature falls a maximum of 2°C below the programmed HIGH SET and LOW SET thresholds as shown in Figure 3. The programmed setting threshold of Figure 3 is user- programmed temperature trip points of either the LOW SET or HIGH SET inputs. The LOW LIMIT or HIGH LIMIT output is driven active when temperature equals the programmed setpoint value (to within 3°C). The output remains active until the temperature falls an additional 2°C below the setpoint due to hysteresis. If the TC623 is used to measure the temperature of another device, it is important that the top surface of the TC623 package be in intimate contact with the measured device. Good thermal conductivity and no air space is critical to accurate temperature measurement in applications of this type. Trip Point Programming The resistance values required for the HIGH SET and LOW SET inputs are calculated using the formula below: RTRIP = 0.5997 x T 2.1312 Where Rtrip = Programming resistor value in Ohms T = Desired trip temperature in degrees Kelvin. For example, to program a trip point of 50°C, the programming resistor is: R TRIP = 0.5997 x (50 + 273.15)2.1312) = 133,652 Ω PROGRAMMED SETPOINT –2°C HYSTERESIS HIGH LIMIT OR LOW LIMIT OUTPUT Figure 3. High Set and Low Set Thresholds