SN75374

QUADRUPLE MOSFET DRIVER

SLRS028A − SEPTEMBER 1988 − REVISED NOVEMBER 2004

8

POST OFFICE BOX 655303

• DALLAS, TEXAS 75265

THERMAL INFORMATION

power-dissipation precautions

Significant power may be dissipated in the SN75374 driver when charging and discharging high-capacitance

loads over a wide voltage range at high frequencies. Figure 12 shows the power dissipated in a typical SN75374

as a function of frequency and load capacitance. Average power dissipated by this driver is derived from the

equation:

PT(AV) = PDC(AV) + PC(AV) + PS(AV)

where PDC(AV) is the steady-state power dissipation with the output high or low, PC(AV) is the power level during

charging or discharging of the load capacitance, and PS(AV) is the power dissipation during switching between

the low and high levels. None of these include energy transferred to the load, and all are averaged over a full

cycle.

The power components per driver channel are:

P

DC(AV) +

(P

HtH

) P

LtL)

T

P

C(AV) [ CV

2f

c

P

S(AV) +

(P

LHtLH

) P

HLtHL)

T

where the times are as defined in Figure 15.

t L

t H

T = 1/f

t LH

t HL

Figure 13. Output-Voltage Waveform