3.1.1. Input Parameter
The required parameters depend on whether the junction temperature is manually entered or auto computed.
|Family||Select the device family.|
Select your device.
Larger devices consume more static power and have higher clock dynamic power. All other power components are unaffected by the device used.
Select the package that is used.
Larger packages provide a larger cooling surface and more contact points to the circuit board, leading to lower thermal resistance. Package selection does not affect dynamic power.
Select the appropriate temperature grade. This field affects the allowed maximum junction temperature range. This field can also be used to determine core voltage for some device families.
Different device families support different temperature grades. For more information about the supported temperature grade and the recommended operating range for the device junction temperature, refer to the respective device family datasheet.
Select typical or theoretical worst-case silicon process.
There is a process variation from die-to-die. This primarily impacts the static power consumption. Typical power characteristic provides results that line up with average device measurements.
Maximum power characteristic provides results that line up with worst-case device measurements. To ensure your power supply design is sufficient to handle the worst-case process variation that affects static power consumption, Intel recommends using the Maximum power characteristic for your power estimation. To enable the Enpirion device selection, you must set Power Characteristics to Maximum.
|VCCINT Voltage (V)||
For Cyclone IV E devices, select the following VCCINT voltage:
|VCC_ONE Voltage (V)||For MAX 10 devices only, select 3.0 V or 3.3 V. The voltage is internally regulated to 1.2 V to supply power to the core and periphery.|
|Power Model Status||This shows if the power model for the device is in preliminary or final version and is only available from EPE 14.0 onwards.|
|VCCL Voltage (V)||For Stratix III devices, select the following VCCL voltage:
|Junction Temp, TJ (°C)||
Enter the junction temperature of the device. This field is only available if you turn on the User Entered T option. In this case, the junction temperature is not calculated based on the thermal information provided.
For Enpirion power device selection, Intel recommends setting Junction Temp, T (°C) to the highest value for the chosen temperature grade.
|Ambient Temp, TA (°C)||
Enter the air temperature near the device. This value can range from –40°C to 125°C. This field is only available when you turn on the Auto Computed T option.
If you turn on the Estimated Theta J option, this field is used to compute the junction temperature based on power dissipation and thermal resistance through the top-side cooling solution (heat sink or none) and board (if applicable).
If you turn on the Custom Theta J option, this field is used to compute junction temperature based on power dissipation and custom θJA entered.
Select the heat sink that is used. You can select one of the following:
If you select None, the heat sink selection updates the custom θSA value and you can see the value in the Custom θSA (°C/W) parameter. If you select Custom, the value is what is entered in the Custom θSA (°C/W) parameter.
Representative examples of heat sinks are provided. Larger heat sinks provide lower thermal resistance and lower the junction temperature. If the heat sink is known, consult the heat sink datasheet and enter a custom θSA value according to the airflow in your system.
Select an available ambient airflow in linear-feet per minute (lfm) or meters per second (m/s). The values are 100 lfm (0.5 m/s), 200 lfm (1.0 m/s), 400 lfm (2.0 m/s), or Still Air. This field is only available if you turn on the Auto Computed T and Estimated Theta J options.
Increased airflow results in a lower case-to-air thermal resistance and lowers the junction temperature.
|Custom θJA (°C/W)||
Enter the junction-to-ambient thermal resistance between the device and ambient air (in °C/W). This field is only available if you turn on the following options:
To compute the overall junction-to-ambient resistance through the top of the device, the Custom θSA parameter is combined with a representative case-to-heatsink resistance and an Intel-provided junction-to-case thermal resistance.
|Board Thermal Mode||
Select the type of board that is used in the thermal analysis. The value is None (Conservative), Typical Board, or JEDEC (2s2p). This field is only available if you turn on the Auto Computed T and Estimated Theta J options.
If you select None (Conservative), the thermal model assumes no heat is dissipated through the board, resulting in a pessimistic calculated junction temperature. This option is not available if the Heat Sink option is set to None.
If you select Typical Board, the thermal model assumes the characteristics of a typical customer board stack, which is based on the selected device and package.
If you select JEDEC (2s2p), the thermal model assumes the characteristics of the JEDEC 2s2p test board specified in standard JESDEC51–9.
To determine the final junction temperature, Intel recommends performing a detailed thermal simulation of your system. This two-resistor thermal model is only for early estimation.
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