| θJA | Thermal resistance, junction to ambient | 61 | °C/W | 20-pin SSOP package () |
| 52 | °C/W | 28-pin VQFN package () |
| 48 | °C/W | 28-pin PDIP package (SP) |
| 52 | °C/W | 28-pin SSOP package (SS) |
| 33 | °C/W | 32-pin VQFN package (RXB) |
| 52 | °C/W | 32-pin TQFP package (PT) |
| TJMAX | Maximum junction temperature | | | Refer to the Absolute Maximum Ratings section |
Note:
- Thermal
resistance (θJA) highly depends on environmental
conditions such as airflow, pressure, and PCB conductivity.
The given values are based on a four-layer standard PCB with
two power planes (2S2P) and without any airflow (refer to
EIA/JESD 51-7).
- Power
dissipation is calculated as follows: PDIS =
VDD × {IDD - Σ IOH} + Σ
{(VDD - VOH) × IOH} + Σ
(VOL × IOL).
- Internal
Power Dissipation is calculated as PINTERNAL =
IDD × VDD, where IDD is
the current to run the chip alone without driving any load
on the output pins.
- Derated Power
is calculated as PDER = PDMAX
(TJ-TA)/θJA, where
TA = Ambient Temperature and TJ =
Junction Temperature.
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