247

Regulator ICs

BA3918

FEstimate of allowable power dissipation

Except under transitional conditions, the power dissipation of this IC is 3W per unit at 25

_C.

See Fig. 4 for thermal derating characteristics, including some cases where heat sinks are used.

A = maximum voltage for VCC

I1 = maximum output current for VDD

I2 = maximum output current for COM

I3 = maximum output current for AMP

I4 = maximum output current for ANT

I5 = maximum output current for AM

I6 = maximum output current for FM

S Power consumed by VDD 5.6V

P1 = (A

* 5.6V)

I1

) (I1 / 20 ) I1 / 10)

A

S Power consumed by COM 8.7V

P2 = (A

* 8.7V)

I2

) (I2 / 30 ) I2 / 10)

A

S Power consumed by AMP

P3 = 1V

I3

) (22mA)

A

S Power consumed by ANT

P4 = 1V

I4

) (22mA)

A

S Power consumed by AM 8.7V

P5 = (A

* 8.7V)

I5

) (I5 / 30 ) I5 / 10)

A

S Power consumed by FM 8.7V

P6 = (A

* 8.7V)

I6

) (I2 / 50 ) I6 / 10)

A

S Power consumed internally by each circuit

P7 = VCC

circuit current (about 5mA)

PMax. = P1

) P2 ) P3 ) P4 ) (P5 or P6, whichever is greater) ) P7