 |
Electronic Components Datasheet Search |
|
|
Electronic Components Datasheet Search |
|
LT3008IDC-TRPBF Datasheet(PDF) 11 Page - Linear Technology |
|
||||||||||||||||||||||||||||||
LT3008IDC-TRPBF Datasheet(HTML) 11 Page - Linear Technology |
|
|
11 / 16 page  LT3008 11 3008f APPLICATIONS INFORMATION Calculating Junction Temperature Example: Given an output voltage of 3.3V, an input volt- age range of 12V ±5%, an output current range of 0mA to 20mA and a maximum ambient temperature of 85°C, what will the maximum junction temperature be for an application using the DC package? The power dissipated by the device is equal to: IOUT(MAX) (VIN(MAX) – VOUT) + IGND (VIN(MAX)) where, IOUT(MAX) = 20mA VIN(MAX) = 12.6V IGND at (IOUT = 20mA, VIN = 12.6V) = 0.3mA So, P = 20mA(12.6V – 3.3V) + 0.3mA(12.6V) = 189.8mW The thermal resistance ranges from 65°C/W to 85°C/W depending on the copper area. So the junction temperature rise above ambient approximately equals: 0.1898W(75°C/W) = 14.2°C The maximum junction temperature equals the maximum junction temperature rise above ambient plus the maximum ambient temperature or: TJ(MAX) = 85°C + 14.2°C = 99.2°C The following tables list thermal resistance for several different board sizes and copper areas. All measurements were taken in still air on 3/32" FR-4 two-layer boards with one ounce copper. PCB layers, copper weight, board layout and thermal vias affect the resultant thermal resistance. Although Tables 2 and 3 provide thermal resistance numbers for 2-layer boards with 1 ounce copper, modern multi-layer PCBs provide better performance than found in these tables. For example, a 4-layer, 1 ounce copper PCB board with 3 thermal vias from the DFN exposed backside or the 3 fused TSOT-23 GND pins to inner layer GND planes achieves 45°C/W thermal resistance. Demo circuit DC 1388A’s board layout achieves this 45°C/W performance. This is approximately a 30% improvement over the lowest numbers shown in Tables 2 and 3. Table 2: Measured Thermal Resistance for DC Package COPPER AREA BOARD AREA THERMAL RESISTANCE (JUNCTION-TO-AMBIENT) TOPSIDE* BACKSIDE 2500mm2 2500mm2 2500mm2 65°C/W 1000mm2 2500mm2 2500mm2 70°C/W 225mm2 2500mm2 2500mm2 75°C/W 100mm2 2500mm2 2500mm2 80°C/W 50mm2 2500mm2 2500mm2 85°C/W *Device is mounted on the topside. Table 3: Measured Thermal Resistance for TSOT-23 Package COPPER AREA BOARD AREA THERMAL RESISTANCE (JUNCTION-TO-AMBIENT) TOPSIDE* BACKSIDE 2500mm2 2500mm2 2500mm2 65°C/W 1000mm2 2500mm2 2500mm2 67°C/W 225mm2 2500mm2 2500mm2 70°C/W 100mm2 2500mm2 2500mm2 75°C/W 50mm2 2500mm2 2500mm2 85°C/W *Device is mounted on the topside. |
Similar Part No. - LT3008IDC-TRPBF |
|
Similar Description - LT3008IDC-TRPBF |
|
|
|
Link URL |
| Privacy Policy |
| ALLDATASHEET.COM |
| Does ALLDATASHEET help your business so far? [ DONATE ] |
About Alldatasheet | Advertisement | Datasheet Upload | 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 |
English ▼
English
Chinese
German
Japanese
Russian
Korean
Spanish
French
Italian
Portuguese
Polish
Vietnamese
Indian
Mexican
British
New Zealand
