SN75372

DUAL MOSFET DRIVER

SLLS025A − JULY 1986

3−7

POST OFFICE BOX 655303

POST OFFICE BOX 1443

THERMAL INFORMATION

power dissipation precautions

Significant power may be dissipated in the SN75372 driver when charging and discharging high-capacitance

loads over a wide voltage range at high frequencies. Figure 5 shows the power dissipated in a typical SN75372

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

equation

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

C(AV) [

CV2

C

f

tHL

tLH

tH

tL

T = 1/f

Figure 12. Output Voltage Waveform

where the times are as defined in Figure 14.

PDC(AV) =

PH t H + PL t L

T

PS(AV) =

PLH t LH + PHL t HL

T

In the following power calculation, both channels are operating under identical conditions:

is negligible and can be ignored.

On a per-channel basis using data sheet values,

P

DC(AV) +

(5 V) 2mA

2

) (20 V) 0mA

2

(0.6)

) (5 V) 16 mA

2

) (20 V) 7mA

2

(0.4)

Power during the charging time of the load capacitance is

Total power for each driver is

and total package power is