Moteur de recherche de fiches techniques de composants électroniques |
|
TMP422AIDCNR Fiches technique(PDF) 8 Page - Burr-Brown (TI) |
|
|
TMP422AIDCNR Fiches technique(HTML) 8 Page - Burr-Brown (TI) |
8 / 26 page www.ti.com SERIES RESISTANCE CANCELLATION DIFFERENTIAL INPUT CAPACITANCE TEMPERATURE MEASUREMENT DATA Standard Binary Temperature Data Calculation TMP421 TMP422 SBOS398A – JULY 2007 – REVISED SEPTEMBER 2007 Table 1. Temperature Data Format (Local and Remote Temperature High Bytes) Series resistance in an application circuit that typically LOCAL/REMOTE TEMPERATURE REGISTER results from printed circuit board (PCB) trace HIGH BYTE VALUE (1 °C RESOLUTION) resistance and remote line length (see Figure 11) is STANDARD BINARY EXTENDED BINARY TEMP automatically cancelled by the TMP421/22, ( °C) BINARY HEX BINARY HEX preventing what would otherwise result in a –64 1100 0000 C0 0000 0000 00 temperature offset. A total of up to 3k Ω of series line –50 1100 1110 CE 0000 1110 0E resistance is cancelled by the TMP421/22, eliminating –25 1110 0111 E7 0010 0111 27 the need for additional characterization and 0 0000 0000 00 0100 0000 40 temperature offset correction. See the two Remote Temperature Error vs Series Resistance typical 1 0000 0001 01 0100 0001 41 characteristic curves (Figure 4 and Figure 5) for 5 0000 0101 05 0100 0101 45 details on the effect of series resistance and 10 0000 1010 0A 0100 1010 4A power-supply voltage on sensed remote temperature 25 0001 1001 19 0101 1001 59 error. 50 0011 0010 32 0111 0010 72 75 0100 1011 4B 1000 1011 8B 100 0110 0100 64 1010 0100 A4 The TMP421/22 tolerate differential input capacitance 125 0111 1101 7D 1011 1101 BD of up to 1000pF with minimal change in temperature 127 0111 1111 7F 1011 1111 BF error. The effect of capacitance on sensed remote 150 0111 1111 7F 1101 0110 D6 temperature error is illustrated in Figure 6, Remote 175 0111 1111 7F 1110 1111 EF Temperature Error vs Differential Capacitance. 191 0111 1111 7F 1111 1111 FF (1) Resolution is 1 °C/count. Negative numbers are represented in Two's Complement format. Temperature measurement data are taken over a (2) Resolution is 1 °C/count. All values are unsigned with a –64°C default range of –55 °C to +127°C for both local and offset. remote locations. Measurements from –55 °C to Both local and remote temperature data use two +150 °C can be made both locally and remotely by bytes for data storage. The high byte stores the reconfiguring the TMP421/22 for the extended temperature with 1 °C resolution. The second or low temperature range. To change the TMP421 and byte stores the decimal fraction value of the TMP422 configuration from the standard to the temperature and allows a higher measurement extended temperature range, switch bit 2 (RANGE) of resolution; see Table 2. The measurement resolution the Configuration Register from low to high. for the both the local and remote channels is Temperature data resulting from conversions within 0.0625 °C, and is not adjustable. the default measurement range are represented in binary form, as shown in Table 1, Standard Binary column. Note that any temperature below –64 °C Example results in a data value of –64 (C0h). Likewise, For positive temperatures (for example, 20 °C): temperatures above +127 °C result in a value of 127 (20 °C)/(1°C/count) = 20 → 14h → 0001 0100 (7Fh). The device can be set to measure over an extended temperature range by changing bit 2 of Two's Complement is not performed on positive Configuration Register 1 from low to high. The numbers. Simply convert the number to binary change in measurement range and data format from code with 8-bit, right-justified format, and standard binary to extended binary occurs at the next MSB = '0' to denote a positive sign. temperature conversion. For data captured in the 20 °C is stored as 0001 0100 → 14h. extended temperature range configuration, an offset For negative temperatures (for example, –20C): of 64 (40h) is added to the standard binary value, as shown in the Extended Binary column of Table 1. (|–20|)/(1 °C/count) = 20 → 14h → 0001 0100 This configuration allows measurement of Generate the Two's Complement of a negative temperatures as low as –64 °C, and as high as number by complementing the absolute value +191 °C; however, most temperature-sensing diodes binary number and adding 1. only measure with the range of –55 °C to +150°C. –20 °C is stored as 1110 1100 → ECh. Additionally, the TMP421/22 are rated only for ambient temperatures ranging from –40 °C to +125°C. Parameters in the Absolute Maximum Ratings table must be observed. 8 Submit Documentation Feedback Copyright © 2007, Texas Instruments Incorporated Product Folder Link(s): TMP421 TMP422 |
Numéro de pièce similaire - TMP422AIDCNR |
|
Description similaire - TMP422AIDCNR |
|
|
Lien URL |
Politique de confidentialité |
ALLDATASHEET.FR |
ALLDATASHEET vous a-t-il été utile ? [ DONATE ] |
À propos de Alldatasheet | Publicité | Contactez-nous | Politique de confidentialité | Echange de liens | Fabricants 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 |