ROHM BH7884EFV Technical note

Class-AB Speaker Amplifiers

1W+1W Stereo
Speaker / Headphone Amplifier

BH7884EFV

●Description

The BH7884EFV is a low voltage, low noise, high output speaker and headphone amplifier drive, in which a Bi-CMOS
process is used. This IC supports: headphone amplifier gain adjustment, active/suspend switching, speaker amplifier
stereo/monaural switching, and amplifier mute switching. All functions are controllable from a microcontroller. Built-in digital
noise reduction circuits eliminate digital noise and BEEP sounds.

●Features

1) Built-in 1W+1W stereo speaker amplifier (Vcc=5V, RL=8, THD=10%)

2) Built-in stereo headphone amplifier

3) Built-in bass boost function for speaker amplifier

4) Built-in low noise VCA (electronic volume) for headphone

5) Built-in mute circuit

6) Built-in standby circuit

7) Low current consumption specifications (9 mA TYP. in ACTIVE mode, 0.2 A TYP. in SUSPEND mode)

●Applications

Notebook computers, LCD TVs, etc.

●Absolute maximum ratings(Ta=25℃)
Parameter Ratings Unit

No.10077EAT06

Supply voltage +6.0 V

Power dissipation 1100 *1 mW

Storage temperature -55 ~ +125 ℃

Operating temperature -10 ~ +70 ℃

*1 Reduced by 11 mW/℃ at 25℃ or higher, when mounting on a 70mmX70mmX1.6mm PCB board).

●Operating Conditions (Ta=25℃)
Parameter Ratings Unit

Supply voltage +3.0~+5.5 V

* This IC is not designed to be radiation-resistant.

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2010.06 - Rev.A

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BH7884EFV

●Electrical characteristics (Unless otherwise noted, VCC=3.3V, Ta=25℃, f=1kHz)

Parameter Symbol

Min. Typ. Max.

Limits

Unit Condition

■1 CHIP
Circuit current ACTV IA - 9.0 18.0 mA No signal ACTIVE

Circuit current SPND Is - 0.2 10.0 µA No signal SUSPEND

■SP AMP
Voltage gain1 GSP1 9.0 12.0 15.0 dB SE, Vin=-18dBV,RL=8Ω

Voltage gain2 GSP2 15.2 18.2 21.2 dB BTL, Vin=-18dBV
Distortion DSP - 0.1 1.0 % BTL, Vin=-18dBV

Technical Note

Maximum output level V
Output noise level V

2.2 5.2 - dBV BTL, DSP=1%

OSP

- -97 -80 dBV SE, DIN-Audio

NSP

Cross talk CTSP - -90 -80 dBV SE, Vin=-18dBV, DIN-Audio
Output level on mute MTSP - -102 -80 dBV BTL, Vin=-18dBV

■HP AMP
Voltage gain 3 GHP 2.6 5.6 8.6 dB VOL:MAX, RL=10kΩ,Vin=-12dBV

Voltage gain 4 GHP -10 -7 -4 dB VOL:MAX, RL=32Ω,Vin=-12dBV
Distortion DHP - 0.025 0.1 % VOL:MAX, RL=32Ω,Vin=-8dBV
Variable width of volume ΔGHP 70 100 - dB VOL:MIN ~ MAX, RL=32Ω
Maximum output level V
Output noise level V
Cross talk CTHP - -98 -80 dBV
Output level on mute MTHP - -110 -80 dBV

-2.0 1.0 - dBV VOL:MAX, DHP=1%, RL=10kΩ

OHP

- -98 -80 dBV VOL:MAX, RL=32Ω, DIN-Audio

NHP

VOL:MAX, R

=32Ω,Vin=-12dBV

L

DIN-Audio
VOL:MAX, R

=32Ω,Vin=-12dBV

L

DIN-Audio

■BEEP AMP
Output voltage level VBP 0.8 1.25 - Vpp Vin=1.3dBV, f=1kHz, 20MHzLPF

■BIAS
Output voltage level V

1.4 1.7 2.0 V No Signal

BIAS

■CTRL
ACTIVE mode V

SUSPEND mode V

VCC-0.3 - VCC V

11H

GND - 0.3 V

11L

SP/ON mode V2H VCC-0.3 - VCC V
SP/OFF mode V2L GND - 0.3 V
BASS-BOOST/ON mode V4H VCC-0.7 - VCC V
BASS-BOOST/OFF mode V4L GND - 0.7 V
STEREO mode V3H VCC-0.7 - VCC V
MONO mode V3L GND - 0.7 V
ACTIVE mode V
MUTE mode V

VCC-0.7 - VCC V

10H

GND - 0.7 V

10L

■PSRR
Ripple rejection ratio GPR - -64 - dBV

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Active mode.
Hold Voltage of 11pin.
Suspend mode.
Hold Voltage of 11pin.

ON mode.

SP
Hold Voltage of 2pin.
SP/OFF mode.
Hold Voltage of 2pin.
SP/Bass Boost mode.
Hold Voltage of 4pin.

Non Boost mode.

SP
Hold Voltage of 4pin.
SP/STEREO mode.
Hold Voltage of 3pin.

MONO mode.

SP
Hold Voltage of 3pin.

Active mode.

HP
Hold Voltage of 10pin.

MUTE mode.

HP
Hold Voltage of 10pin.

f=100Hz, 0.3Vpp, SIN Input
SPOUT monitor, DIN-Audio

2010.06 - Rev.A

BH7884EFV

●Block diagram

Technical Note

Fig.1

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2010.06 - Rev.A

BH7884EFV

●Control pin settings

H SP ACTIVE SPAMP is in active state

L SP MUTE SPAMP is in suspend state

H STEREO For SPAMP, LCH and RCH both are in active state

L MONO For SPAMP, LCH is in active state and RCH is in suspend state

H BASS BOOST For SPAMP, bass is boosted

L NON -BOOST For SPAMP, bass is not boosted

H ACTIVE HPAMP is in active state

L MUTE HPAMP is in mute state

Technical Note

SP MUTE PIN:2PIN

STEREO/MONO PIN:3PIN

BASSBOOST PIN:4PIN

MUTE PIN:10PIN

(The SPAMP mute function is realized by connecting HP_OUT to SP_IN)

SUSPEND PIN:11PIN

H ACTIVE The IC is in active state

L SUSPEND The IC is in suspend state

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2010.06 - Rev.A