Hello,
One of our customers is using the LM2903AQ1 (part number LM2903AVQPWRQ1 / LM2903AVQPWRG4Q1).
Stated that:
Device is AEC-Q100 Qualified with the Following Results: Device Temperature Grade 1: 40°C to 125°C Operating Ambient Temperature range -40°C to +125°C, which usually means:
1. Ambient Operating Temperature -40°C to +125°C
2. Junction Temperature -40°C to +150°C
In the datasheet (pages 3 and 4) it is reported:
1. θJA Package thermal impedance (PW package) max 149°C/W
2. θJA Package thermal impedance (DGK package) max 199.4°C/W
3. RθJCtop Junction-to-case (top) thermal resistance (DGK package) max 120.8°C/W
4. ψJT Junction-to-top characterization parameter (DGK package) max 21.5°C/W
In Spra953b.pdf app note it is reported:
1. The actual junction temperature can be very closely estimated using:
2. Equation 8: Tjunction = Tcase + (ψJT * Power)
Can you tell me what is the maximum temperature on the package (Tcase) you can reach without exceeding maximum junction temperature (Tj)?
Customer is expecting a formal declaration from TI about the following topics:
- Maximum allowed junction temperature Tj and accurate specification of ψJT for the selected package (PW) or at least a formula to calculate exactly the junction temperature from the case temperature.
- Confirmation that the device may work for an indefinite time and within operating specifications at case temperature above 125°C if maximum Tj and maximum power dissipation are not exceeded.
Regards,
Meir
