SN75374_14 Datasheet, PDF (9/19 Pages) Texas Instruments – QUADRUPLE MOSFET DRIVER

SN75374
QUADRUPLE MOSFET DRIVER
SLRS028A − SEPTEMBER 1988 − REVISED NOVEMBER 2004
THERMAL INFORMATION
power-dissipation precautions (continued)
P_L, P_H, P_LH, and P_HL are the respective instantaneous levels of power dissipation, and C is the load capacitance.
V_C is the voltage across the load capacitance during the charge cycle shown by the equation:
V_C = V_OH − V_OL
P_S(AV) may be ignored for power calculations at low frequencies.
In the following power calculation, all four channels are operating under identical conditions: f = 0.2 MHz,
V_OH = 19.9 V and V_OL = 0.15 V with V_CC1 = 5 V, V_CC2 = 20 V, V_CC3 = 24 V, V_C = 19.75 V, C = 1000 pF, and the
duty cycle = 60%. At 0.2 MHz for C_L < 2000 pF, P_S(AV) is negligible and can be ignored. When the output voltage
is low, I_CC2 is negligible and can be ignored.
On a per-channel basis using data-sheet values,
ƪ ǒ Ǔ ǒ Ǔ ǒ Ǔƫ P_DC(AV) +
5V
4 mA
4
)
20 V
−2.2 mA
4
)
24 V
2.2 mA
4
0.6 )
ƪ ǒ Ǔ ǒ Ǔ ǒ Ǔƫ 5 V
31 mA
4
)
20 V
0 mA
4
)
24 V
16 mA
4
0.4
P_DC(AV) = 58.2 mW per channel
Power during the charging time of the load capacitance is
P_C(AV) = (1000 pF)(19.75 V)²(0.2 MHz) = 78 mW per channel
Total power for each driver is:
P_T(AV) = 58.2 mW + 78 mW = 136.2 mW
The total package power is:
P_T(AV) = (136.2)(4) = 544.8 mW
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