BD88420GUL-E2 Datasheet BD88420GUL-E2, BD88410GUL-E2, BD88415GUL-E2 | P16-P18

Technical Note

16/21

BD88400GUL,BD88410GUL,BD88415GUL,BD88420GUL

www.rohm.com

2011.03 – Rev. A

[UVLO / SHUTDOWN CONTROL]

BD884xxGUL has low voltage protection function (UVLO: Under Voltage Lock Out). And protect from the illegal operation of

IC by a low power supply voltage.

The detection voltage is 2.13V

@Typ.

, so it does not influence 2.4V of recommended operation voltage. UVLO controls the

whole of IC, and does both the negative power supply charge pump and the headphone amplifier in power down.

[TSD]

BD884xxGUL has overheating protection function (TSD: Thermal Shutdown). And the headphone amplifier becomes

shutdown when illegally overheating by the headphone amplifier illegally operation.

●Timming Chart

(Usually Operation)

PVDD,SV DD

SHDNLB

SHDNRB

PVSS,SVSS

INL,INR

OUTL

OUTR

Shutdow n Setup Signal output Shutdow n

Amp enable

Fig.66 Usually Operation

(UVLO Operation)

PVDD,SVDD

SHDNLB,

SHDNRB

PVSS,SVSS

OUTL

OUTR

SetupSignal output Signal outputUVLO

Fig.67 UVLO Operation

(TSD Operation)

PV DD, SV DD

SHDNLB,

SHDNRB

PVSS,SVSS

OUTL

OUTR

Signal output Signal outputTSD

Ta

Hy steresis = 5℃

Fig.68 TSD Operation

Technical Note

17/21

BD88400GUL,BD88410GUL,BD88415GUL,BD88420GUL

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2011.03 – Rev. A

●Application Circuit

Fig.69 BD88410GU/BD88415GUL/BD88420GUL application circuit

Fig.70 BD88400GUL application circuit

In BD88400GUL, the Pass Gain becomes the following formula (4). The Pass Gain and the resister Rf is limited by table.3.

i

f

R

Gain  (4)

Table.3 Pass Gain and Resister Limit

Item Min. Typ. Max. Unit

Pass Gain 0.5 1.0 2.0 V/V

Rf 1.0 10 - kΩ

Ri - 10 - kΩ

Ri is not limited. But, if this resister Ri is very small, the signal decrease happens in the low frequency (Refer to formula 2).

Part Function value Remarks

CF

Flying

Capacitor

2.2µF

Temp. Characteristic：

Class-B

CH

Hold

Capacitor

2.2µF

Temp. Characteristic：

Class-B

Cpvdd

Bypass

Capacitor

1.0µF

Temp. Characteristic：

Class-B

Csvdd

Bypass

Capacitor

1.0µF

Temp. Characteristic：

Class-B

Cil

Coupling

Capacitor

1.0µF

Temp. Characteristic：

Class-B

Cir

Coupling

Capacitor

1.0µF

Temp. Characteristic：

Class-B

Part Function value Remarks

CF

Flying

Capacitor

2.2µF

Temp. Characteristic：

Class-B

CH

Hold

Capacitor

2.2µF

Temp. Characteristic：

Class-B

Cpvdd

Bypass

Capacitor

1.0µF

Temp. Characteristic：

Class-B

Csvdd

Bypass

Capacitor

1.0µF

Temp. Characteristic：

Class-B

Cil

Coupling

Capacitor

1.0µF

Temp. Characteristic：

Class-B

Cir

Coupling

Capacitor

1.0µF

Temp. Characteristic：

Class-B

Ri

Input

Resistor

10kΩ

MCR006YZPJ103

(ROHM)

Rf

Feedback

Resistor

10kΩ

MCR006YZPJ103

(ROHM)

D2

+

-

SVDD

SVSS

+

-

SVDD

SVSS

SHORT

PROTECTION

TSD

SGND

UVLO/

SHUTDOWN

CONTROL

C2

Rin

Rfb

Rin

C1

A1

B2B1

D1

CHARGE

PUMP

CLOCK

GENERATOR

SVDD

D3

SVDD

SVSS

A3

A4

B4

C4

D4

SGND

A2

PVDD

C1P

PGND

C1N

PVSS

SVDD

OUTL

OUTR

SVSS

CHARGE

PUMP

CONTROL

PVDD

3.3V

1.0μF

2.2μF

1.0μF

Rch Input

3.3V

1.0μF

SHUTDOWN

Control

1.0μF

Lch Input

CF

CH

Cpvdd

Csvdd

Cil

Cir

INR INL

SHDNLB

SHDNRB

SGND

Technical Note

18/21

BD88400GUL,BD88410GUL,BD88415GUL,BD88420GUL

www.rohm.com

2011.03 – Rev. A

●Thermal Derating Curve

The reference value of the thermal derating curve is indicated in Fig.71.

(Conditions)

This value is for mounted on the ROHM application board

Board size：40mm x 60mm x 1.6mm

Top Copper Area：79.9%

Bottom Copper Area：80.2%

Board Layout：Fig.74

Fig.71 Thermal Derating Curve

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

0 25 50 75 100 125 150

Ta [

℃

]

Pd [W]

BD88420GUL-E2

BD88420GUL-E2

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