Electronic Components Datasheet Search |
|
TMP01ESZ1 Datasheet(PDF) 8 Page - Analog Devices |
|
TMP01ESZ1 Datasheet(HTML) 8 Page - Analog Devices |
8 / 20 page TMP01 Rev. E | Page 8 of 20 THEORY OF OPERATION The TMP01 is a linear voltage-output temperature sensor, with a window comparator that can be programmed by the user to activate one of two open-collector outputs when a predeter- mined temperature setpoint voltage has been exceeded. A low drift voltage reference is available for setpoint programming. The temperature sensor is basically a very accurate, temperature compensated, band gap-type voltage reference with a buffered output voltage proportional to absolute temperature (VPTAT), accurately trimmed to a scale factor of 5 mV/K. The low drift 2.5 V reference output VREF is easily divided externally with fixed resistors or potentiometers to accurately establish the programmed heat/cool setpoints, independent of temperature. Alternatively, the setpoint voltages can be supplied by other ground referenced voltage sources such as user- programmed DACs or controllers. The high and low setpoint voltages are compared to the temperature sensor voltage, thus creating a two-temperature thermostat function. In addition, the total output current of the reference (IVREF) determines the magnitude of the temperature hysteresis band. The open collector outputs of the comparators can be used to control a wide variety of devices. VPTAT V+ WINDOW COMPARATOR TEMPERATURE OUTPUT HYSTERESIS CURRENT CURRENT MIRROR HYSTERESIS VOLTAGE ENABLE TMP01 VREF SET HIGH SET LOW GND UNDER OVER 8 5 6 7 1 4 3 2 VOLTAGE REFERENCE AND SENSOR 1k Ω IHYS Figure 13. Detailed Block Diagram TEMPERATURE HYSTERESIS The temperature hysteresis is the number of degrees beyond the original setpoint temperature that must be sensed by the TMP01 before the setpoint comparator is reset and the output disabled. Figure 14 shows the hysteresis profile. The hysteresis is programmed by the user by setting a specific load on the reference voltage output VREF. This output current IVREF is also called the hysteresis current, which is mirrored internally and fed to a buffer with an analog switch. HYSTERESIS HIGH HYSTERESIS LOW LO HI OUTPUT VOLTAGE OVER, UNDER TEMPERATURE HYSTERESIS HIGH = HYSTERESIS LOW TSETLOW TSETHIGH Figure 14. TMP01 Hysteresis Profile After a temperature setpoint is exceeded and a comparator tripped, the buffer output is enabled. The output is a current of the appropriate polarity that generates a hysteresis offset volt- age across an internal 1000 Ω resistor at the comparator input. The comparator output remains on until the voltage at the comparator input, now equal to the temperature sensor voltage VPTAT summed with the hysteresis offset, returns to the programmed setpoint voltage. The comparator then returns low, deactivating the open-collector output and disabling the hysteresis current buffer output. The scale factor for the programmed hysteresis current is: IHYS = IVREF = 5 μA/°C + 7 μA Thus, since VREF = 2.5 V, with a reference load resistance of 357 kΩ or greater (output current 7 μA or less), the temper- ature setpoint hysteresis is zero degrees. Larger values of load resistance only decrease the output current below 7 μA and have no effect on the operation of the device. The amount of hysteresis is determined by selecting a value of load resistance for VREF. PROGRAMMING THE TMP01 In the basic fixed setpoint application utilizing a simple resistor ladder voltage divider, the desired temperature setpoints are programmed in the following sequence: 1. Select the desired hysteresis temperature. 2. Calculate the hysteresis current IVREF. 3. Select the desired setpoint temperatures. 4. Calculate the individual resistor divider ladder values needed to develop the desired comparator setpoint voltages at SET HIGH and SET LOW. |
Similar Part No. - TMP01ESZ1 |
|
Similar Description - TMP01ESZ1 |
|
|
Link URL |
Privacy Policy |
ALLDATASHEET.NET |
Does ALLDATASHEET help your business so far? [ DONATE ] |
About Alldatasheet | Advertisement | Contact us | Privacy Policy | Link Exchange | Manufacturer List All Rights Reserved©Alldatasheet.com |
Russian : Alldatasheetru.com | Korean : Alldatasheet.co.kr | Spanish : Alldatasheet.es | French : Alldatasheet.fr | Italian : Alldatasheetit.com Portuguese : Alldatasheetpt.com | Polish : Alldatasheet.pl | Vietnamese : Alldatasheet.vn Indian : Alldatasheet.in | Mexican : Alldatasheet.com.mx | British : Alldatasheet.co.uk | New Zealand : Alldatasheet.co.nz |
Family Site : ic2ic.com |
icmetro.com |