BA3948FP各脚功能电路原理芯片引脚定义引脚图及功能IC贸易商-中国IC网-芯三七

Regulator ICs

System power supply for CD player-

equipped audio systems

BA3950A

With 13.3V (external transistor required), 12V, 10V, and 5.6V outputs, the BA3950A power supply IC is best suited for

CD player-equipped audio systems.

FApplications

CD player-equipped audio systems

FFeatures

1) 13.3V (external transistor required), 12V, 10V, and

5.6V outputs are built in (one output for each volt-

age).

3) Thermal protection circuit prevents heat damage to

the IC.

4) CompactSIP-M12packageallowsalargepowerdis-

sipation.

2) Output current limit circuit protects the IC against

short-circuiting damage.

FAbsolute maximum ratings (Ta = 25_C)

FRecommended operating conditions (Ta = 25_C)

199

Regulator ICs

BA3950A

FBlock diagram

FPin descriptions

200

Regulator ICs

BA3950A

FInput / output circuits

201

Regulator ICs

BA3950A

FElectrical characteristics (unless otherwise noted, Ta = 25_C and VCC = 8V)

202

Regulator ICs

BA3950A

FCircuit operation

The MAIN, MOTOR, and µ-COM outputs rise when ST is 1.4V (Typ.).

The CDP output rises when MODE is 1.4V (Typ.) and ST is 1.4V (Typ.).

203

Regulator ICs

BA3950A

FApplication example

FOperation notes

(1) Operating power supply voltage

(3) Preventing oscillation at each output

When operating within proper ranges of power supply

voltage and ambient temperature, most circuit functions

are guaranteed. Although the rated values of electrical

characteristics cannot be absolutely guaranteed, char-

acteristic values do not change drastically within the

proper ranges.

To stop oscillation of output, make sure to connect a ca-

pacitor having a valve 1µF or greater between GND and

each output pin. Also, be sure to connect a bypass ca-

pacitor between V^CCand GND for further stabilization of

output. (To avoid the noise effect, layout the grounding

close to the IC.) Oscillation can occur if capacitance is

susceptible to temperature. We recommend using a tan-

talum electrolytic capacitor with minimal changes in ca-

pacitance.

(2) Power dissipation (Pd)

Refer to the heat reduction characteristics (Fig. 4) and

the rough estimation of IC power dissipation given on a

separate page. If power dissipation exceeds the allow-

able limit, the functionality of IC will be degraded (such

as reduction of current capacity by increased chip tem-

perature). Make sure to use the IC within the allowable

range of power dissipation with a sufficient margin.

204

Regulator ICs

BA3950A

(4) Overcurrent protection circuit

(5) Thermal protection circuit

An overcurrent protection circuit is installed in each out-

put system, based on the respective output current. This

prevents IC destruction by overcurrent, by limiting the

current with a curve shape of “7” in the voltage-current

graph. The IC is designed with margins so that current

flow will be restricted and latching will be prevented even

if a large current suddenly flows through a large capaci-

tor. Note that these protection circuits are only good for

preventing damage from sudden accidents. Make sure

your design does not cause the protection circuit to oper-

ate continuously under transitional conditions (for

instance, when output is clamped at 1V^For higher). Note

thatthecircuitabilityisnegativelycorrelatedwithtemper-

ature.

A built-in thermal protection circuit prevents thermal

damage to the IC. All outputs are switched OFF when the

circuit operates, and revert to the original state when

temperature drops to a certain level.

(6) Improving ripple rejection by capacitors

Ripple rejection of the CDP and MAIN outputs can be im-

provedby installing a capacitor that reduces the AC gain.

(7) Malfunction in intense electric fields

Note that bringing the IC into an intense electric field

(such as a radio relay station) may result in malfunction.

FThermal derating curve

Estimate of allowable power dissipation (P^MAX.)

S Power consumed by CDP

P¹= (VCC * CDP) maximum load current of CDP

P²= {VCC * (µ-COM)} maximum load current of µ-COM

P³= (VCC * MAIN) maximum load current of MAIN

P⁴= VCC supply current

S Power consumed by µ-COM

S Power consumed by MAIN

S Power consumed internally by each circuit

P^MAX.= P1 ) P2 ) P3 ) P4

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Regulator ICs

BA3950A

FExternal dimensions (Units: mm)

206

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