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ZHCSMT3A november 2020 – march 2023 ALM2403-Q1

PRODUCTION DATA

封装选项

机械数据 (封装 | 引脚)

PWP|14
- MPDS370A

散热焊盘机械数据 (封装 | 引脚)

PWP|14
- PPTD393

订购信息

8.2.2.2 Power Dissipation and Thermal Reliability

Power dissipation is critical to many industrial and automotive applications. Resolvers are typically chosen over other position feedback techniques because of reliability and accuracy in harsh conditions and high temperatures.

The ALM2403-Q1 is capable of high output current with power-supply voltages up to 24 V. Internal power dissipation increases when operating at high supply voltages. The power dissipated in the op amp (P_OPA) is calculated using Equation 4:

Equation 4.

P_{O P A} = (V_{S} - V_{O U T}) \times I_{O U T} = (V_{S} - V_{O U T}) \times \frac{V_{O U T}}{R_{L}}

To calculate the worst-case power dissipation in the op amp, the ac and dc cases must be considered separately.

In the case of constant output current (dc) to a resistive load, the maximum power dissipation in the op amp occurs when the output voltage is half the positive supply voltage. This calculation assumes that the op amp is sourcing current from the positive supply to a grounded load. If the op amp sinks current from a grounded load, modify Equation 5 to include the negative supply voltage instead of the positive.

Equation 5.

P_{O P A (M A X ⎽ D C)} = P_{O P A} (\frac{V_{S}}{2}) = \frac{{(V_{S})}^{2}}{4 \times R_{L}}

The ac maximum of average power dissipation in the op amp for a sinusoidal output current (ac) to a resistive load occurs when the peak output voltage is 2/π times the supply voltage, given symmetrical supply voltages, as shown in Equation 6:

Equation 6.

P_{O P A (P E A K ⎽ A C)} = P_{O P A} (\frac{{2 \times V}_{S}}{π}) = \frac{{2 \times (V_{S})}^{2}}{π^{2} \times R_{L}}

After the total power dissipation is determined, the junction temperature at the worst expected ambient temperature case must be determined by using Equation 7:

Equation 7.

T_{J (M A X)} = P_{O P A} \times R_{θ J A} + T_{A (M A X)}