LM26LVCISDX-075

LM26LV 1.6 V, LLP-6 Factory Preset Temperature Switch and Temperature Sensor May 16, 2008 LM26LV 1.6 V, LLP-6 Factory Preset Temperature Switch and Temperature Sensor General Description The LM26LV is a low-voltage, precision, dual-output, lowpower temperature switch and temperature sensor. The temperature trip point (TTRIP) can be preset at the factory to any temperature in the range of 0°C to 150°C in 1°C increments. Built-in temperature hysteresis (THYST) keeps the output stable in an environment of temperature instability. In normal operation the LM26LV temperature switch outputs assert when the die temperature exceeds TTRIP. The temperature switch outputs will reset when the temperature falls below a temperature equal to (TTRIP − THYST). The OVERTEMP digital output, is active-high with a push-pull structure, while the OVERTEMP digital output, is active-low with an open-drain structure. An analog output, VTEMP, delivers an analog output voltage which is inversely proportional to the measured temperature. Driving the TRIP TEST input high: (1) causes the digital outputs to be asserted for in-situ verification and, (2) causes the threshold voltage to appear at the VTEMP output pin, which could be used to verify the temperature trip point. The LM26LV's low minimum supply voltage makes it ideal for 1.8 Volt system designs. Its wide operating range, low supply current , and excellent accuracy provide a temperature switch solution for a wide range of commercial and industrial applications. ■ ■ ■ ■ Automotive Disk Drives Games Appliances Features ■ ■ ■ ■ ■ ■ ■ ■ ■ Low 1.6V operation Low quiescent current Push-pull and open-drain temperature switch outputs Wide trip point range of 0°C to 150°C Very linear analog VTEMP temperature sensor output VTEMP output short-circuit protected Accurate over −50°C to 150°C temperature range 2.2 mm by 2.5 mm (typ) LLP-6 package Excellent power supply noise rejection Key Specifications ■ Supply Voltage ■ Supply Current ■ Accuracy, Trip Point Temperature 1.6V to 5.5V 8 μA (typ) 0°C to 150°C 0°C to 150°C 0°C to 120°C −50°C to 0°C ±2.2°C ±2.3°C ±2.2°C ±1.7°C ±100 μA −50°C to 150°C 4.5°C to 5.5°C ■ Accuracy, VTEMP ■ VTEMP Output Drive ■ Operating Temperature ■ Hysteresis Temperature Applications ■ ■ ■ ■ ■ Cell phones Wireless Transceivers Digital Cameras Personal Digital Assistants (PDA's) Battery Management Connection Diagram LLP-6 Typical Transfer Characteristic VTEMP Analog Voltage vs Die Temperature 20204701 Top View See NS Package Number SDB06A 20204724 © 2008 National Semiconductor Corporation 202047 www.national.com LM26LV Block Diagram 20204703 Pin Descriptions Pin No. Name Type Equivalent Circuit Description TRIP TEST pin. Active High input. If TRIP TEST = 0 (Default) then: VTEMP = VTS, Temperature Sensor Output Voltage If TRIP TEST = 1 then: OVERTEMP and OVERTEMP outputs are asserted and VTEMP = VTRIP, Temperature Trip Voltage. This pin may be left open if not used. Over Temperature Switch output Active High, Push-Pull Asserted when the measured temperature exceeds the Trip Point Temperature or if TRIP TEST = 1 This pin may be left open if not used. Over Temperature Switch output Active Low, Open-drain (See Section 2.1 regarding required pullup resistor.) Asserted when the measured temperature exceeds the Trip Point Temperature or if TRIP TEST = 1 This pin may be left open if not used. VTEMP Analog Voltage Output If TRIP TEST = 0 then VTEMP = VTS, Temperature Sensor Output Voltage If TRIP TEST = 1 then VTEMP = VTRIP, Temperature Trip Voltage This pin may be left open if not used. Positive Supply Voltage Power Supply Ground 1 TRIP TEST Digital Input 5 OVERTEMP Digital Output 3 OVERTEMP Digital Output 6 VTEMP Analog Output 4 2 VDD GND Power Ground www.national.com 2 LM26LV Typical Application 20204702 3 www.national.com LM26LV Ordering Information Order Number LM26LVCISD-150 LM26LVCISDX-150 LM26LVCISD-145 LM26LVCISDX-145 LM26LVCISD-140 LM26LVCISDX-140 LM26LVCISD-135 LM26LVCISDX-135 LM26LVCISD-130 LM26LVCISDX-130 LM26LVCISD-125 LM26LVCISDX-125 LM26LVCISD-120 LM26LVCISDX-120 LM26LVCISD-115 LM26LVCISDX-115 LM26LVCISD-110 LM26LVCISDX-110 LM26LVCISD-105 LM26LVCISDX-105 LM26LVCISD-100 LM26LVCISDX-100 LM26LVCISD-095 LM26LVCISDX-095 LM26LVCISD-090 LM26LVCISDX-090 LM26LVCISD-085 LM26LVCISDX-085 LM26LVCISD-080 LM26LVCISDX-080 LM26LVCISD-075 LM26LVCISDX-075 LM26LVCISD-070 LM26LVCISDX-070 LM26LVCISD-065 LM26LVCISDX-065 LM26LVCISD-060 LM26LVCISDX-060 LM26LVCISD-050 LM26LVCISDX-050 Temperature Trip Point, °C 150°C 150°C 145°C 145°C 140°C 140°C 135°C 135°C 130°C 130°C 125°C 125°C 120°C 120°C 115°C 115°C 110°C 110°C 105°C 105°C 100°C 100°C 95°C 95°C 90°C 90°C 85°C 85°C 80°C 80°C 75°C 75°C 70°C 70°C 65°C 65°C 60°C 60°C 50°C 50°C NS Package Number SDB06A SDB06A SDB06A SDB06A SDB06A SDB06A SDB06A SDB06A SDB06A SDB06A SDB06A SDB06A SDB06A SDB06A SDB06A SDB06A SDB06A SDB06A SDB06A SDB06A SDB06A SDB06A SDB06A SDB06A SDB06A SDB06A SDB06A SDB06A SDB06A SDB06A SDB06A SDB06A SDB06A SDB06A SDB06A SDB06A SDB06A SDB06A SDB06A SDB06A Top Mark 150 150 145 145 140 140 135 135 130 130 125 125 120 120 115 115 110 110 105 105 100 100 095 095 090 090 085 085 080 080 075 075 070 070 065 065 060 060 050 050 Transport Media 1000 Units on Tape and Reel 4500 Units on Tape and Reel 1000 Units on Tape and Reel 4500 Units on Tape and Reel 1000 Units on Tape and Reel 4500 Units on Tape and Reel 1000 Units on Tape and Reel 4500 Units on Tape and Reel 1000 Units on Tape and Reel 4500 Units on Tape and Reel 1000 Units on Tape and Reel 4500 Units on Tape and Reel 1000 Units on Tape and Reel 4500 Units on Tape and Reel 1000 Units on Tape and Reel 4500 Units on Tape and Reel 1000 Units on Tape and Reel 4500 Units on Tape and Reel 1000 Units on Tape and Reel 4500 Units on Tape and Reel 1000 Units on Tape and Reel 4500 Units on Tape and Reel 1000 Units on Tape and Reel 4500 Units on Tape and Reel 1000 Units on Tape and Reel 4500 Units on Tape and Reel 1000 Units on Tape and Reel 4500 Units on Tape and Reel 1000 Units on Tape and Reel 4500 Units on Tape and Reel 1000 Units on Tape and Reel 4500 Units on Tape and Reel 1000 Units on Tape and Reel 4500 Units on Tape and Reel 1000 Units on Tape and Reel 4500 Units on Tape and Reel 1000 Units on Tape and Reel 4500 Units on Tape and Reel 1000 Units on Tape and Reel 4500 Units on Tape and Reel www.national.com 4 LM26LV Absolute Maximum Ratings (Note 1) Supply Voltage Voltage at OVERTEMP pin Voltage at OVERTEMP and VTEMP pins TRIP TEST Input Voltage Output Current, any output pin Input Current at any pin (Note 2) Storage Temperature Maximum Junction Temperature TJ(MAX) ESD Susceptibility (Note 3) : Human Body Model −0.2V to +6.0V −0.2V to +6.0V −0.2V to (VDD + 0.5V) −0.2V to (VDD + 0.5V) ±7 mA 5 mA −65°C to +150°C +155°C 4500V Machine Model 300V Charged Device Model 1000V Soldering process must comply with National's Reflow Temperature Profile specifications. Refer to www.national.com/packaging. (Note 4) Operating Ratings Specified Temperature Range: LM26LV Supply Voltage Range (VDD) (Note 1) −50°C ≤ TA ≤ +150°C  TMIN ≤ TA ≤ TMAX +1.6 V to +5.5 V 152 °C/W Thermal Resistance (θJA) (Note 5) LLP-6 (Package SDB06A) Accuracy Characteristics Trip Point Accuracy Parameter Trip Point Accuracy (Note 8) Conditions 0 − 150°C VDD = 5.0 V Limits (Note 7) ±2.2 Units (Limit) °C (max) VTEMP Analog Temperature Sensor Output Accuracy There are four gains corresponding to each of the four Temperature Trip Point Ranges. Gain 1 is the sensor gain used for Temperature Trip Point 0 - 69°C. Likewise Gain 2 is for Trip Points 70 - 109 °C; Gain 3 for 110 - 129 °C; and Gain 4 for 130 - 150 °C. These limits do not include DC load regulation. These stated accuracy limits are with reference to the values in the LM26LV Conversion Table. Parameter Conditions TA = 20°C to 40°C TA = 0°C to 70°C Gain 1: for Trip Point Range 0 - 69°C TA = 0°C to 90°C TA = 0°C to 120°C TA = 0°C to 150°C TA = −50°C to 0°C TA = 20°C to 40°C TA = 0°C to 70°C Gain 2: for Trip Point Range 70 - 109°C VTEMP Temperature Accuracy (Note 8) Gain 3: for Trip Point Range 110 - 129°C TA = 0°C to 90°C TA = 0°C to 120°C TA = 0°C to 150°C TA = −50°C to 0°C TA = 20°C to 40°C TA = 0°C to 70°C TA = 0°C to 90°C TA = 0°C to 120°C TA = 0°C to 150°C TA = −50°C to 0°C TA = 20°C to 40°C TA = 0°C to 70°C Gain 4: for Trip Point Range 130 - 150°C TA = 0°C to 90°C TA = 0°C to 120°C TA = 0°C to 150°C TA = −50°C to 0°C VDD = 1.6 to 5.5 V VDD = 1.6 to 5.5 V VDD = 1.6 to 5.5 V VDD = 1.6 to 5.5 V VDD = 1.6 to 5.5 V VDD = 1.7 to 5.5 V VDD = 1.8 to 5.5 V VDD = 1.9 to 5.5 V VDD = 1.9 to 5.5 V VDD = 1.9 to 5.5 V VDD = 1.9 to 5.5 V VDD = 2.3 to 5.5 V VDD = 2.3 to 5.5 V VDD = 2.5 to 5.5 V VDD = 2.5 to 5.5 V VDD = 2.5 to 5.5 V VDD = 2.5 to 5.5 V VDD = 3.0 to 5.5 V VDD = 2.7 to 5.5 V VDD = 3.0 to 5.5 V VDD = 3.0 to 5.5 V VDD = 3.0 to 5.5 V VDD = 3.0 to 5.5 V VDD = 3.6 to 5.5 V Limits (Note 7) ±1.8 ±2.0 ±2.1 ±2.2 ±2.3 ±1.7 ±1.8 ±2.0 ±2.1 ±2.2 ±2.3 ±1.7 ±1.8 ±2.0 ±2.1 ±2.2 ±2.3 ±1.7 ±1.8 ±2.0 ±2.1 ±2.2 ±2.3 ±1.7 °C (max) °C (max) °C (max) °C (max) Units (Limit) 5 www.national.com LM26LV Electrical Characteristics Unless otherwise noted, these specifications apply for +VDD = +1.6V to +5.5V. Boldface limits apply for TA = TJ = TMIN to TMAX ; all other limits TA = TJ = 25°C. Symbol Parameter Conditions Typical (Note 6) Limits (Note 7) Units (Limit) GENERAL SPECIFICATIONS IS Quiescent Power Supply Current Hysteresis OVERTEMP DIGITAL OUTPUT ACTIVE HIGH, PUSH-PULL VDD ≥ 1.6V VDD ≥ 2.0V VOH Logic "1" Output Voltage VDD ≥ 3.3V VDD ≥ 1.6V VDD ≥ 2.0V VDD ≥ 3.3V BOTH OVERTEMP and OVERTEMP DIGITAL OUTPUTS VDD ≥ 1.6V VDD ≥ 2.0V VOL Logic "0" Output Voltage VDD ≥ 3.3V VDD ≥ 1.6V VDD ≥ 2.0V VDD ≥ 3.3V OVERTEMP DIGITAL OUTPUT IOH Logic "1" Output Leakage Current (Note 12) TA = 30 °C TA = 150 °C Gain 1: If Trip Point = 0 - 69°C VTEMP Sensor Gain Gain 2: If Trip Point = 70 - 109°C Gain 3: If Trip Point = 110 - 129°C Gain 4: If Trip Point = 130 - 150°C Source ≤ 90 μA 1.6V ≤ VDD < 1.8V VTEMP Load Regulation (Note 10) VDD ≥ 1.8V Sink ≤ 100 μA (VDD − VTEMP) ≥ 200 mV VTEMP ≥ 260 mV Source ≤ 120 μA Sink ≤ 200 μA (VDD − VTEMP) ≥ 200 mV Sink ≤ 385 μA Sink ≤ 500 μA Sink ≤ 730 μA Sink ≤ 690 μA Sink ≤ 1.05 mA Sink ≤ 1.62 mA 0.001 0.025 −5.1 −7.7 −10.3 −12.8 −0.1 0.1 −0.1 0.1 1 0.29 VDD = +1.6V to +5.5V 74 −82 Without series resistor. See Section 4.2 1100 −1 1 −1 1 0.45 0.2 V (max) Source ≤ 340 μA Source ≤ 498 μA Source ≤ 780 μA Source ≤ 600 μA Source ≤ 980 μA Source ≤ 1.6 mA VDD − 0.45V V (min) VDD − 0.2V V (min) 8 5 16 5.5 4.5 μA (max) °C (max) °C (Min) ACTIVE LOW, OPEN DRAIN 1 μA (max) VTEMP ANALOG TEMPERATURE SENSOR OUTPUT mV/°C mV/°C mV/°C mV/°C mV (max) mV (max) mV (max) mV (max) Ohm mV μV/V dB pF (max) VTEMP ≥ 260 mV Source or Sink = 100 μA VDD Supply- to-VTEMP DC Line Regulation (Note 13) CL VTEMP Output Load Capacitance www.national.com 6 LM26LV Electrical Characteristics Unless otherwise noted, these specifications apply for +VDD = +1.6V to +5.5V. Boldface limits apply for TA = TJ = TMIN to TMAX ; all other limits TA = TJ = 25°C. Symbol Parameter Conditions Typical (Note 6) Limits (Note 7) VDD− 0.5 0.5 1.5 0.001 2.5 1 Units (Limit) V (min) V (max) μA (max) μA (max) TRIP TEST DIGITAL INPUT VIH VIL IIH IIL TIMING Time from Power On to Digital Output Enabled. See definition below. (Note 11). Time from Power On to Analog Temperature Valid. See definition below. (Note 11) Logic "1" Threshold Voltage Logic "0" Threshold Voltage Logic "1" Input Current Logic "0" Input Current (Note 12) tEN 1.1 2.3 ms (max) tVTEMP 0.9 10 ms (max) Definitions of tEN and tVTEMP 20204751 20204750 7 www.national.com LM26LV Notes Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the device is functional, but do not guarantee specific performance limits. For guaranteed specifications and test conditions, see the Electrical Characteristics. The guaranteed specifications apply only for the test conditions listed. Some performance characteristics may degrade when the device is not operated under the listed test conditions. Note 2: When the input voltage (VI) at any pin exceeds power supplies (VI < GND or VI > VDD), the current at that pin should be limited to 5 mA. Note 3: The Human Body Model (HBM) is a 100 pF capacitor charged to the specified voltage then discharged through a 1.5 kΩ resistor into each pin. The Machine Model (MM) is a 200 pF capacitor charged to the specified voltage then discharged directly into each pin. The Charged Device Model (CDM) is a specified circuit characterizing an ESD event that occurs when a device acquires charge through some triboelectric (frictional) or electrostatic induction processes and then abruptly touches a grounded object or surface. Note 4: Reflow temperature profiles are different for lead-free and non-lead-free packages. Note 5: The junction to ambient temperature resistance (θJA) is specified without a heat sink in still air. Note 6: Typicals are at TJ = TA = 25°C and represent most likely parametric norm. Note 7: Limits are guaranteed to National's AOQL (Average Outgoing Quality Level). Note 8: Accuracy is defined as the error between the measured and reference output voltages, tabulated in the Conversion Table at the specified conditions of supply gain setting, voltage, and temperature (expressed in °C). Accuracy limits include line regulation within the specified conditions. Accuracy limits do not include load regulation; they assume no DC load. Note 9: Changes in output due to self heating can be computed by multiplying the internal dissipation by the temperature resistance. Note 10: Source currents are flowing out of the LM26LV. Sink currents are flowing into the LM26LV. Note 11: Guaranteed by design. Note 12: The 1 µA limit is based on a testing limitation and does not reflect the actual performance of the part. Expect to see a doubling of the current for every 15°C increase in temperature. For example, the 1 nA typical current at 25°C would increase to 16 nA at 85°C. Note 13: Line regulation (DC) is calculated by subtracting the output voltage at the highest supply voltage from the output voltage at the lowest supply voltage. The typical DC line regulation specification does not include the output voltage shift discussed in Section 4.3. Note 14: The curves shown represent typical performance under worst-case conditions. Performance improves with larger overhead (VDD − VTEMP), larger VDD, and lower temperatures. Note 15: The curves shown represent typical performance under worst-case conditions. Performance improves with larger VTEMP, larger VDD and lower temperatures. www.national.com 8 LM26LV Typical Performance Characteristics VTEMP Output Temperature Error vs. Temperature Minimum Operating Temperature vs. Supply Voltage 20204707 20204706 Supply Current vs. Temperature Supply Current vs. Supply Voltage 20204704 20204705 Load Regulation, 100 mV Overhead T = 80°C Sourcing Current (Note 14) Load Regulation, 200 mV Overhead T = 80°C Sourcing Current (Note 14) 20204740 20204746 9 www.national.com LM26LV Load Regulation, 400 mV Overhead T = 80°C Sourcing Current (Note 14) Load Regulation, 1.72V Overhead T = 150°C, VDD = 2.4V Sourcing Current (Note 14) 20204747 20204748 Load Regulation, VDD = 1.6V Sinking Current (Note 15) Load Regulation, VDD = 1.8V Sinking Current (Note 15) 20204741 20204744 Load Regulation, VDD = 2.4V Sinking Current (Note 15) Change in VTEMP vs. Overhead Voltage 20204742 20204745 www.national.com 10 LM26LV VTEMP Supply-Noise Gain vs. Frequency VTEMP vs. Supply Voltage Gain 1: For Trip Points 0 - 69°C 20204743 20204734 VTEMP vs. Supply Voltage Gain 2: For Trip Points 70 - 109°C VTEMP vs. Supply Voltage Gain 3: For Trip Points 110 - 129°C 20204735 20204736 VTEMP vs. Supply Voltage Gain 4: For Trip Points 130 - 150°C 20204737 11 www.national.com LM26LV 1.0 LM26LV VTEMP vs Die Temperature Conversion Table The LM26LV has one out of four possible factory-set gains, Gain 1 through Gain 4, depending on the range of the Temperature Trip Point. The VTEMP temperature sensor voltage, in millivolts, at each discrete die temperature over the complete operating temperature range, and for each of the four Temperature Trip Point ranges, is shown in the Conversion Table below. This table is the reference from which the LM26LV accuracy specifications (listed in the Electrical Characteristics section) are determined. This table can be used, for example, in a host processor look-up table. See Section 1.1.1 for the parabolic equation used in the Conversion Table. VTEMP Temperature Sensor Output Voltage vs Die Temperature Conversion Table The VTEMP temperature sensor output voltage, in mV, vs Die Temperature, in °C, for each of the four gains corresponding to each of the four Temperature Trip Point Ranges. Gain 1 is the sensor gain used for Temperature Trip Point 0 - 69°C. Likewise Gain 2 is for Trip Points 70 - 109 °C; Gain 3 for 110 - 129 °C; and Gain 4 for 130 - 150 °C. VDD = 5.0V. The values in bold font are for the Trip Point range. VTEMP, Analog Output Voltage, mV Die Temp., °C −50 −49 −48 −47 −46 −45 −44 −43 −42 −41 −40 −39 −38 −37 −36 −35 −34 −33 −32 −31 −30 −29 −28 −27 −26 −25 −24 −23 www.national.com −22 −21 −20 −19 −18 −17 −16 −15 −14 −13 −12 −11 −10 −9 −8 −7 −6 −5 −4 −3 −2 −1 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 1172 1167 1162 1157 1152 1147 1142 1137 1132 1127 1122 1116 1111 1106 1101 1096 1091 1086 1081 1076 1071 1066 1061 1056 1051 1046 1041 1035 1030 1025 1020 1015 1010 1005 1000 995 990 985 980 974 969 964 959 954 949 944 939 934 928 923 918 1757 1750 1742 1735 1727 1720 1712 1705 1697 1690 1682 1674 1667 1659 1652 1644 1637 1629 1621 1614 1606 1599 1591 1583 1576 1568 1561 1553 1545 1538 1530 1522 1515 1507 1499 1492 1484 1477 1469 1461 1454 1446 1438 1431 1423 1415 1407 1400 1392 1384 1377 2343 2333 2323 2313 2303 2293 2283 2272 2262 2252 2242 2232 2222 2212 2202 2192 2182 2171 2161 2151 2141 2131 2121 2111 2101 2090 2080 2070 2060 2050 2040 2029 2019 2009 1999 1989 1978 1968 1958 1948 1938 1927 1917 1907 1897 1886 1876 1866 1856 1845 1835 2929 2916 2903 2891 2878 2866 2853 2841 2828 2815 2803 2790 2777 2765 2752 2740 2727 2714 2702 2689 2676 2664 2651 2638 2626 2613 2600 2587 2575 2562 2549 2537 2524 2511 2498 2486 2473 2460 2447 2435 2422 2409 2396 2383 2371 2358 2345 2332 2319 2307 2294 Gain 1: for TTRIP = 0-69°C 1312 1307 1302 1297 1292 1287 1282 1277 1272 1267 1262 1257 1252 1247 1242 1237 1232 1227 1222 1217 1212 1207 1202 1197 1192 1187 1182 1177 Gain 2: Gain 3: Gain 4: for for for TTRIP = TTRIP = TTRIP = 70-109°C 110-129°C 130-150°C 1967 1960 1952 1945 1937 1930 1922 1915 1908 1900 1893 1885 1878 1870 1863 1855 1848 1840 1833 1825 1818 1810 1803 1795 1788 1780 1773 1765 2623 2613 2603 2593 2583 2573 2563 2553 2543 2533 2523 2513 2503 2493 2483 2473 2463 2453 2443 2433 2423 2413 2403 2393 2383 2373 2363 2353 3278 3266 3253 3241 3229 3216 3204 3191 3179 3166 3154 3141 3129 3116 3104 3091 3079 3066 3054 3041 3029 3016 3004 2991 2979 2966 2954 2941 12 LM26LV 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 913 908 903 898 892 887 882 877 872 867 862 856 851 846 841 836 831 825 820 815 810 805 800 794 789 784 779 774 769 763 758 753 748 743 737 732 727 722 717 711 706 701 696 690 685 680 675 670 664 659 654 1369 1361 1354 1346 1338 1331 1323 1315 1307 1300 1292 1284 1276 1269 1261 1253 1245 1238 1230 1222 1214 1207 1199 1191 1183 1176 1168 1160 1152 1144 1137 1129 1121 1113 1105 1098 1090 1082 1074 1066 1059 1051 1043 1035 1027 1019 1012 1004 996 988 980 1825 1815 1804 1794 1784 1774 1763 1753 1743 1732 1722 1712 1701 1691 1681 1670 1660 1650 1639 1629 1619 1608 1598 1588 1577 1567 1557 1546 1536 1525 1515 1505 1494 1484 1473 1463 1453 1442 1432 1421 1411 1400 1390 1380 1369 1359 1348 1338 1327 1317 1306 2281 2268 2255 2242 2230 2217 2204 2191 2178 2165 2152 2139 2127 2114 2101 2088 2075 2062 2049 2036 2023 2010 1997 1984 1971 1958 1946 1933 1920 1907 1894 1881 1868 1855 1842 1829 1816 1803 1790 1776 1763 1750 1737 1724 1711 1698 1685 1672 1659 1646 1633 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 649 643 638 633 628 622 617 612 607 601 596 591 586 580 575 570 564 559 554 549 543 538 533 527 522 517 512 506 501 496 490 485 480 474 469 464 459 453 448 443 437 432 427 421 416 411 405 400 395 389 384 972 964 957 949 941 933 925 917 909 901 894 886 878 870 862 854 846 838 830 822 814 807 799 791 783 775 767 759 751 743 735 727 719 711 703 695 687 679 671 663 655 647 639 631 623 615 607 599 591 583 575 1296 1285 1275 1264 1254 1243 1233 1222 1212 1201 1191 1180 1170 1159 1149 1138 1128 1117 1106 1096 1085 1075 1064 1054 1043 1032 1022 1011 1001 990 979 969 958 948 937 926 916 905 894 884 873 862 852 841 831 820 809 798 788 777 766 1620 1607 1593 1580 1567 1554 1541 1528 1515 1501 1488 1475 1462 1449 1436 1422 1409 1396 1383 1370 1357 1343 1330 1317 1304 1290 1277 1264 1251 1237 1224 1211 1198 1184 1171 1158 1145 1131 1118 1105 1091 1078 1065 1051 1038 1025 1011 998 985 971 958 13 www.national.com LM26LV 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 379 373 368 362 357 352 346 341 336 330 325 320 314 309 303 298 293 287 282 277 567 559 551 543 535 527 519 511 503 495 487 479 471 463 455 447 438 430 422 414 756 745 734 724 713 702 691 681 670 659 649 638 627 616 606 595 584 573 562 552 945 931 918 904 891 878 864 851 837 824 811 797 784 770 757 743 730 716 703 690 linear formula below can be used. Using this formula, with the constant and slope in the following set of equations, the bestfit VTEMP vs Die Temperature performance can be calculated with an approximation error less than 18 mV. VTEMP is in mV. 1.1.3 First-Order Approximation (Linear) over Small Temperature Range For a linear approximation, a line can easily be calculated over the desired temperature range from the Conversion Table using the two-point equation: 1.1 VTEMP vs DIE TEMPERATURE APPROXIMATIONS The LM26LV's VTEMP analog temperature output is very linear. The Conversion Table above and the equation in Section 1.1.1 represent the most accurate typical performance of the VTEMP voltage output vs Temperature. 1.1.1 The Second-Order Equation (Parabolic) The data from the Conversion Table, or the equation below, when plotted, has an umbrella-shaped parabolic curve. VTEMP is in mV. Where V is in mV, T is in °C, T1 and V1 are the coordinates of the lowest temperature, T2 and V2 are the coordinates of the highest temperature. For example, if we want to determine the equation of a line with Gain 4, over a temperature range of 20°C to 50°C, we would proceed as follows: Using this method of linear approximation, the transfer function can be approximated for one or more temperature ranges of interest. 1.1.2 The First-Order Approximation (Linear) For a quicker approximation, although less accurate than the second-order, over the full operating temperature range the www.national.com 14 LM26LV 2.0 OVERTEMP and OVERTEMP Digital Outputs The OVERTEMP Active High, Push-Pull Output and the OVERTEMP Active Low, Open-Drain Output both assert at the same time whenever the Die Temperature reaches the factory preset Temperature Trip Point. They also assert simultaneously whenever the TRIP TEST pin is set high. Both outputs de-assert when the die temperature goes below the Temperature Trip Point - Hysteresis. These two types of digital outputs enable the user the flexibility to choose the type of output that is most suitable for his design. Either the OVERTEMP or the OVERTEMP Digital Output pins can be left open if not used. 2.1 OVERTEMP OPEN-DRAIN DIGITAL OUTPUT The OVERTEMP Active Low, Open-Drain Digital Output, if used, requires a pull-up resistor between this pin and VDD. The following section shows how to determine the pull-up resistor value. Determining the Pull-up Resistor Value (1) We see that for VOL of 0.2 V the electrical specification for OVERTEMP shows a maximim isink of 385 µA. (2) Let iL= 1 µA, then iT is about 386 µA max. If we select 35 µA as the current limit then iT for the calculation becomes 35 µA (3) We notice that VDD(Max) is 3.3V + 0.3V = 3.6V and then calculate the pull-up resistor as RPull-up = (3.6 − 0.2)/35 µA = 97k (4) Based on this calculated value, we select the closest resistor value in the tolerance family we are using. In our example, if we are using 5% resistor values, then the next closest value is 100 kΩ. 2.2 NOISE IMMUNITY The LM26LV is virtually immune from false triggers on the OVERTEMP and OVERTEMP digital outputs due to noise on the power supply. Test have been conducted showing that, with the die temperature within 0.5°C of the temperature trip point, and the severe test of a 3 Vpp square wave "noise" signal injected on the VDD line, over the VDD range of 2V to 5V, there were no false triggers. 3.0 TRIP TEST Digital Input The TRIP TEST pin simply provides a means to test the OVERTEMP and OVERTEMP digital outputs electronically by causing them to assert, at any operating temperature, as a result of forcing the TRIP TEST pin high. When the TRIP TEST pin is pulled high the VTEMP pin will be at the VTRIP voltage. If not used, the TRIP TEST pin may either be left open or grounded. 4.0 VTEMP Analog Temperature Sensor Output 20204752 The Pull-up resistor value is calculated at the condition of maximum total current, iT, through the resistor. The total current is: The VTEMP push-pull output provides the ability to sink and source significant current. This is beneficial when, for example, driving dynamic loads like an input stage on an analogto-digital converter (ADC). In these applications the source current is required to quickly charge the input capacitor of the ADC. See the Applications Circuits section for more discussion of this topic. The LM26LV is ideal for this and other applications which require strong source or sink current. 4.1 NOISE CONSIDERATIONS The LM26LV's supply-noise gain (the ratio of the AC signal on VTEMP to the AC signal on VDD) was measured during bench tests. It's typical attenuation is shown in the Typical Performance Characteristics section. A load capacitor on the output can help to filter noise. For operation in very noisy environments, some bypass capacitance should be present on the supply within approximately 2 inches of the LM26LV. 4.2 CAPACITIVE LOADS The VTEMP Output handles capacitive loading well. In an extremely noisy environment, or when driving a switched sampling input on an ADC, it may be necessary to add some filtering to minimize noise coupling. Without any precautions, the VTEMP can drive a capacitive load less than or equal to 1100 pF as shown in Figure 1. For capacitive loads greater than 1100 pF, a series resistor is required on the output, as shown in Figure 2, to maintain stable conditions. where, iT iL VOUT VDD(Max) iT is the maximum total current through the Pull-up Resistor at VOL. iL is the load current, which is very low for typical digital inputs. VOUT is the Voltage at the OVERTEMP pin. Use VOL for calculating the Pull-up resistor. VDD(Max) is the maximum power supply voltage to be used in the customer's system. The pull-up resistor maximum value can be found by using the following formula: EXAMPLE CALCULATION Suppose we have, for our example, a V DD of 3.3 V ± 0.3V, a CMOS digital input as a load, a VOL of 0.2 V. 15 www.national.com LM26LV 20204715 FIGURE 1. LM26LV No Decoupling Required for Capacitive Loads Less than 1100 pF. To ensure good temperature conductivity, the backside of the LM26LV die is directly attached to the GND pin (Pin 2). The temperatures of the lands and traces to the other leads of the LM26LV will also affect the temperature reading. Alternatively, the LM26LV can be mounted inside a sealedend metal tube, and can then be dipped into a bath or screwed into a threaded hole in a tank. As with any IC, the LM26LV and accompanying wiring and circuits must be kept insulated and dry, to avoid leakage and corrosion. This is especially true if the circuit may operate at cold temperatures where condensation can occur. If moisture creates a short circuit from the VTEMP output to ground or VDD, the VTEMP output from the LM26LV will not be correct. Printed-circuit coatings are often used to ensure that moisture cannot corrode the leads or circuit traces. The thermal resistance junction-to-ambient (θJA) is the parameter used to calculate the rise of a device junction temperature due to its power dissipation. The equation used to calculate the rise in the LM26LV's die temperature is 20204733 CLOAD 1.1 nF to 99 nF 100 nF to 999 nF 1 μF RS 3 kΩ 1.5 kΩ 800 Ω where TA is the ambient temperature, IQ is the quiescent current, IL is the load current on the output, and VO is the output voltage. For example, in an application where TA = 30 °C, VDD = 5 V, IDD = 9 μA, Gain 4, VTEMP = 2231 mV, and IL = 2 μA, the junction temperature would be 30.021 °C, showing a self-heating error of only 0.021°C. Since the LM26LV's junction temperature is the actual temperature being measured, care should be taken to minimize the load current that the VTEMP output is required to drive. If The OVERTEMP output is used with a 100 k pull-up resistor, and this output is asserted (low), then for this example the additional contribution is [(152° C/W)x(5V)2/100k] = 0.038°C for a total selfheating error of 0.059°C. Figure 3 shows the thermal resistance of the LM26LV. Device Number LM26LVCISD NS Package Number SDB06A Thermal Resistance (θJA) 152° C/W FIGURE 2. LM26LV with series resistor for capacitive loading greater than 1100 pF. 4.3 VOLTAGE SHIFT The LM26LV is very linear over temperature and supply voltage range. Due to the intrinsic behavior of an NMOS/PMOS rail-to-rail buffer, a slight shift in the output can occur when the supply voltage is ramped over the operating range of the device. The location of the shift is determined by the relative levels of VDD and VTEMP. The shift typically occurs when VDD − VTEMP = 1.0V. This slight shift (a few millivolts) takes place over a wide change (approximately 200 mV) in VDD or VTEMP. Since the shift takes place over a wide temperature change of 5°C to 20°C, VTEMP is always monotonic. The accuracy specifications in the Electrical Characteristics table already includes this possible shift. FIGURE 3. LM26LV Thermal Resistance 5.0 Mounting and Temperature Conductivity The LM26LV can be applied easily in the same way as other integrated-circuit temperature sensors. It can be glued or cemented to a surface. www.national.com 16 LM26LV 6.0 Applications Circuits 20204761 FIGURE 4. Temperature Switch Using Push-Pull Output 20204762 FIGURE 5. Temperature Switch Using Open-Drain Output 20204728 Most CMOS ADCs found in microcontrollers and ASICs have a sampled data comparator input structure. When the ADC charges the sampling cap, it requires instantaneous charge from the output of the analog source such as the LM26LV temperature sensor and many op amps. This requirement is easily accommodated by the addition of a capacitor (CFILTER). The size of CFILTER depends on the size of the sampling capacitor and the sampling frequency. Since not all ADCs have identical input stages, the charge requirements will vary. This general ADC application is shown as an example only. FIGURE 6. Suggested Connection to a Sampling Analog-to-Digital Converter Input Stage 17 www.national.com LM26LV 20204718 FIGURE 7. Celsius Temperature Switch 20204760 FIGURE 8. TRIP TEST Digital Output Test Circuit 20204765 The TRIP TEST pin, normally used to check the operation of the OVERTEMP and OVERTEMP pins, may be used to latch the outputs whenever the temperature exceeds the programmed limit and causes the digital outputs to assert. As shown in the figure, when OVERTEMP goes high the TRIP TEST input is also pulled high and causes OVERTEMP output to latch high and the OVERTEMP output to latch low. Momentarily switching the TRIP TEST input low will reset the LM26LV to normal operation. The resistor limits the current out of the OVERTEMP output pin. FIGURE 9. Latch Circuit using OVERTEMP Output www.national.com 18 LM26LV Physical Dimensions inches (millimeters) unless otherwise noted 6-Lead LLP-6 Package Order Number LM26LVCISD, LM26LVCISDX NS Package Number SDB06A 19 www.national.com LM26LV 1.6 V, LLP-6 Factory Preset Temperature Switch and Temperature Sensor Notes For more National Semiconductor product information and proven design tools, visit the following Web sites at: Products Amplifiers Audio Clock Conditioners Data Converters Displays Ethernet Interface LVDS Power Management Switching Regulators LDOs LED Lighting PowerWise Serial Digital Interface (SDI) Temperature Sensors Wireless (PLL/VCO) www.national.com/amplifiers www.national.com/audio www.national.com/timing www.national.com/adc www.national.com/displays www.national.com/ethernet www.national.com/interface www.national.com/lvds www.national.com/power www.national.com/switchers www.national.com/ldo www.national.com/led www.national.com/powerwise www.national.com/sdi www.national.com/tempsensors www.national.com/wireless WEBENCH Analog University App Notes Distributors Green Compliance Packaging Design Support www.national.com/webench www.national.com/AU www.national.com/appnotes www.national.com/contacts www.national.com/quality/green www.national.com/packaging www.national.com/quality www.national.com/refdesigns www.national.com/feedback Quality and Reliability Reference Designs Feedback THE CONTENTS OF THIS DOCUMENT ARE PROVIDED IN CONNECTION WITH NATIONAL SEMICONDUCTOR CORPORATION (“NATIONAL”) PRODUCTS. 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