Class-AB Speaker Amplifiers
2W + 2W Stereo
Speaker / Headphone Amplifier
No.10077EAT05
BH7881EFV
●Description
The BH7881EFV is a low voltage, low noise, high output speaker/headphone amplifier IC, in which a Bi-CMOS process is
used. An on-chip speaker amplifier circuit that is capable of 2W+2W output can be used as a headphone amplifier by
switching the operating mode. This makes it possible to configure an audio system using few external devices.
With a built-in, low saturation regulator with programmable output voltage and output current, clear tone quality is obtained
even when directly connected to a digital power supply. A peripheral analog circuit can also be regulator driven. Furthermore,
the BH7881EFV provides speaker output and VREG output short-circuit detection functions, a thermal shutdown function with
hysteresis, and a speaker protection function.
●Features
1) Built-in low saturation type regulator (Digital power supply driver, voltage and current variable, short circuit detection)
2) Bass boost mode, gain switching functions
3) Speaker MUTE function (Headphone mode)
4) Built-in line amplifier output (gain adjustment, LPF setting) active/suspend function (TTL input control pin)
5) Hysteretic thermal shutdown function (Set for approximately 150℃ /90℃)
6) IC protection function (SP pin VCC/GND short circuit detection)
7) Speaker protection function (Output voltage amplitude control)
●Applications
Notebook computers, LCD TVs, etc.
●Absolute maximum ratings (Ta=25℃)
Parameter
Ratings
Unit
+6.0
V
1100 *1
mW
Storage temperature
-55~+125
℃
Operating temperature
-10~+70
℃
Supply voltage
Power dissipation
*1 Reduced by 11 mW/℃ at 25℃ or higher, when mounting on a 70mmX70mmX1.6mm PCB board).
●Operating Conditions (Ta=25℃)
Parameter
Supply voltage
Ratings
Unit
+3.3~+5.5
V
* This IC is not designed to be radiation-resistant.
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1/9
2010.06 - Rev.A
Technical Note
BH7881EFV
●Electrical characteristics (Unless otherwise noted, VCC=3.3V,Ta=25℃,f=1kHz,R=4Ω,400Hz~30kHzBPF)
Limits
Parameter
Unit
Conditions
Min.
Typ.
Max.
■1CHIP
Circuit current (ACTIVE)
-
18
30
mA
No signal
Circuit current(SUSPEND)
-
0
10
μA
No signal
Voltage gain1
8.5
11.0
13.5
dB
SE,Vin=-18dBV
Voltage gain 2
14.5
17.0
19.5
dB
BTL,Vin=-18dBV
-
0.04
1.0
%
BTL,Vin=-18dBV
1.5
4.5
-
dBV
BTL,DSTN=1%
Output noise level
-
-90
-80
dBV
SE,DIN-Audio
Cross talk
-
-85
-75
dBV
SE,DIN-Audio
Output level on mute
-
-110
-80
dBV
BTL,Vin=-18dBV
3.0
5.5
8.0
dB
SE,Vin=-18dBV,RL=32Ω
-
0.02
1.0
%
SE,Vin=-18dBV,RL=32Ω
-1.6
1.4
-
dBV
SE,DSTN=1% ,RL=10kΩ
Output noise level
-
-95
-80
dBV
SE,DIN-Audio ,RL=32Ω
Cross talk
-
-90
-80
dBV
SE,DIN-Audio ,RL=32Ω
Output level on mute
-
-105
-80
dBV
SE,Vin=-18dBV,RL=32Ω
1.40
1.65
1.90
V
No signal
2.7
3.0
-
V
No signal
-
-80
-
dBV
VCC/3+0.8
-
VCC
V
SP/HP® SUSPEND
0
-
0.8
V
SP/HP® ACTIVE
VCC/3+0.8
-
VCC
V
SP/HP ON
0
-
0.8
V
SP OFF(SP MUTE),HP ON
■SP AMP
Distortion
Maximum output level
■HP AMP
Voltage gain
Distortion
Maximum output level
■BIAS
Output voltage
■Regulator
Output voltage
PSRR
VIN=0.28Vpp,1kHz
■CONTROL PIN
ACTV/SPND CTRL 2PIN control pin
SUSPEND mode
ACTIVE mode
SP/HP CTRL 12PIN control pin
SP&HP mode
HP(SP MUTE) mode
BASSBOOST CTRL 11PIN control pin
Bass-Boost mode
VCC/3+0.8
-
VCC
V
SP/HP gain UP
Non-Boost mode
0
-
0.8
V
SP/HP gain NORMAL
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2/9
2010.06 - Rev.A
Technical Note
BH7881EFV
●Block diagram
Fig.1
●Control pin descriptions
1. ACTIVE/SUSPEND:2PIN
Control input
Mode
H
SUSPEND
Function
Suspended state (Except REG)
L
ACTIVE
Active state
When suspended, the regulator (REG) is in an active state and the SP/HP/LINE amplifier is in a suspended state. Originally,
signals from input resistance and feedback resistance leaked into the speaker output even when suspended, because of
the series connection of an inverting amplifier. However, since the signals are cut off on their way in this IC, signal leaks do
not occur in speaker output. (Signals due to feedback resistance are output in LINE amplifier output.)
2. POWER LEVEL:8PIN
Control input
Mode
Function
H
Limiter H
3Vf peak limiter ON (Output approx. 1.25 W)
OPEN
Limiter L
2Vf peak limiter ON(Output approx .0.70W)
L
Limiter OFF
limiter OFF
*VCC=5V,RL=4ohm,VIN=-8dBV
Since a limiter uses diode characteristics, it has temperature characteristics. On the high temperature side, amplitude tends
to decrease, which is a characteristic that protects the IC. Since setting in speaker mode is assumed, it is ineffective (limiter
OFF) in headphone mode. Moreover, precautions must be taken when input is so great, that output becomes a square
wave, since this could cause local oscillation.
3. BASSBOOST ON/OFF:11PIN
Control input
Mode
H
ON
Function
BASSBOOST:ON
L
OFF
BASSBOOST:OFF
The capacitor that constitutes BASSBOOST is eliminated, and also functions as a gain switch.
4. SP/HP:12PIN
Control input
H
Mode
SP+HP
Function
SP:ON, HP:ON
L
HP
SP:OFF,HP:ON
By using the headphone mode in a speaker MUTE mode, it is possible to completely cut off the pop noise when switching
when VCC ON or OFF, or to ACTV or SPND. For control sequence and other information, see the following pages.
*Not all control pins have pull up or pull internal resistors. Therefore add pull up or pull down resistors, accordingly (PIN8 is an exception.)
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2010.06 - Rev.A
Technical Note
BH7881EFV
●Description of operations
1. LINE Amplifier
1) The voltage gain of the LINE amplifier is calculated by the following equations:
GAIN = 20×LOG(68k/R4 +1k)) [dB]
R4 and R9 are resistances connected to PIN4 and PIN9
GAIN = 20×LOG(68k/R9 +1k)) [dB]
2)
In order to make it operable with mixing input, the LINE amplifier can be realized by connecting multiple resistors to
PIN4 and PIN9. Since the input pin is also the feedback of an inverting differential amplifier, each individual signal is
simply added.
3)
To configure LPF and remove unnecessary frequency components, the LINE amplifier can be realized by connecting
capacitors between PIN3 and PIN4, and between PIN9 and PIN10. The LPF cut-off frequency at that time is calculated
by the following equation:
fc = 1/(2×π×C×68k) [Hz]
2. SP Amplifier (HP Amplifier)
1) The voltage gain of the SP amplifier for Non-Boost is about 12 [dB] (SE: Single end).
2)
The voltage gain of the SP amplifier for Bass-Boost is calculated by the following equations:
GAIN = 20×LOG((40k+R22-23)/10k) [dB] Where R22-23 is the resistance connected between PIN22 and PIN23.
GAIN = 20×LOG((40k+R14-15)/10k) [dB] Where R14-15 is the resistance connected between PIN14 and PIN15.
3)
The cut-off frequency for Bass-Boost is calculated by the following equations:
Where RC22-23 is connected between PIN22 and PIN23.
fc = 1/(2×π×C22-23×R22-23) [Hz]
fc = 1/(2×π×C14-15×R14-15) [Hz]
Where RC14-15 is connected between PIN14 and PIN15.
4)
Apply power to RCHVCC (PIN13), for MONO only.
3. Regulator
1) The REG output voltage is calculated by the following equation, and numeric values are shown below:
V = 1.15 [V]×(1+R(VLEV)/R(VREF)) [V]
REG setting voltage
3.0
3.3
3.6
4.0
4.6
V
Supply voltage(VCC)
3.3
3.6
4.0
5.0
5.0
V
R(VLEV)
30k
30k
30k
30k
30k
Ω
R(VREF)
18k
16k
14k
12k
10k
Ω
Use 1% resistors to eliminate errors in actual output voltages.
2)
The REG maximum output current is determined by the external Tr capability (hFE) of the IC. If more current is
necessary, select one ICMAX with large hFE. Drive output current to the base is about 5 mA.
3)
When using the regulator, connect REG output to PIN6. The LINE amplifier, BIAS, and other sections essential to tone
quality, are driven by the REG voltage. Clear sound output is obtained even if a digital power supply is the VCC.
4)
When using the regulator for an application, other than this IC, and driving the IC by VCC only, apply VCC at PIN6.
5)
When not using the regulator, it is set to OFF mode by connecting PIN 19 to OPEN and PIN18 to OPEN. Apply VCC at
PIN6.
6)
Do not set a VCC applied voltage that is smaller than the set voltage of the regulator. Since the REG output transistor
operates in a saturation region, an abnormal circuit current occurs.
7)
For the REG output transistor, Rohm transistors 2SA1900 and 2SA933 are recommended.
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2010.06 - Rev.A
Technical Note
BH7881EFV
4. Short circuit detection
1) Overview of SP amplifier VCC/GND short circuit detection.
If the output pin of the SP amplifier is short circuited to VCC or GND, the detection function operates to suspend the
output stage of the SP amplifier.
If the SP output pin is short circuited to REG output, the detection function does not operate. It is configured so that it
resets automatically if the short circuit is canceled. Moreover, although a short circuit is detected from the DC voltage
of the output pin, and there is a short delay distinguishing it from maximum output amplitude, malfunction may occur
due to factors such as power supply voltage and load. In this case, connect “PIN7” to GND. The short circuit function
is set to the OFF mode.
2)
SP amplifier VCC/GND short circuit detection cautions
When the output pin of the SP amplifier is short circuited with VCC or GND, excessive current flows in the IC and stress
is applied to the chip. Accordingly, if it is shorted a number of times, the IC gradually deteriorates and is finally
destroyed. The short circuit detection function does not guarantee operation after numerous shorts.
3)
Regulator short circuit detection
If the output pin of the regulator is short circuited to GND, the detection function operates to suspend the output stage
of the regulator. If the output pin of the regulator is short circuited to VCC, an abnormal current does not occur in any
circuit. After the short circuit, the regulator resets automatically, due to the pull-up resistance (for example, 2.2 kΩ)
connected to PIN1, as shown in the full option example of the sample application circuit.
(Example: 3.9 kΩ is the resistance load for lowering the output impedance of the regulator when it is no load.)
5. Pop noise
1) The following table shows the sequence for eliminating the pop noise that occurs from turning the power supply
ON or OFF, or turning control pins ON or OFF.
2)
Order
VCC
ACT/SPND
SP/HP
Conditions
1
OFF
SUSPEND
HP
Power Supply ON
2
ON
SUSPEND
HP
Turning on in the suspend
3
ON
ACTIVE
HP
SP MUTE~countermeasure
4
ON
ACTIVE
SP+HP
MUTE cancellation~operation
5
ON
ACTIVE
SP+HP
Operation
6
ON
ACTIVE
HP
SP MUTE~counter measure
7
ON
SUSPEND
HP
Turning off in the suspend
8
OFF
SUSPEND
HP
Power Supply OFF
In speaker MUTE state, pop noise does not occur even when starting or changing modes. It is recommended to use
speaker MUTE (headphone) mode during conditions where pop noise can occur.
3 ) Any changes of the components values in the sample application circuit can the effect the pop noise cut-off function.
6. Bypass and bias capacitor
1) Although this IC is designed so that bypass capacitors are not needed, when bypass capacitors are in fact necessary,
place them close to the VCC~GND pins.
2)
Similarly, place a bias capacitor close to the GND pin.
7. Capacitive load drive
1) Do not connect a capacitive load to the SP amplifier, HP amplifier, or IC pin. There is a possibility of oscillation.
2)
Adding RC to the HP amplifier output, as in the sample application circuit, makes the output noise, voltage, and
distortion sensitive to oscillation.
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5/9
2010.06 - Rev.A
Technical Note
BH7881EFV
8. Pop noise at start/end when switching ACTV/SPND
Pop noise can be suppressed by mode transition due to software as in “Pop noise” above, or by hardware as shown below.
This is realized (in SP mode) by forcibly setting HP mode temporarily, using the CR differential circuit.
Fig.2
9. Power package
1) In order to expand the power dissipation of the package, make the GND pattern, directly below the IC, as wide as
possible and solder the GND pattern to the back of the IC.
2) Power dissipation of the package varies greatly depending on factors such as the number of layers, area, film thickness,
and material quality of the board used.
10. Other
Beween voltages of VCC=1.4~1.6 V, momentary oscillation sometimes is observed at the SPOUT pin. Nevertheless, this
occurrence is not reproduced on a momentary rise or fall of VCC. When slowly raising VCC pay attention to transient
voltage. In order to avoid such occurrences, a sample circuit is illustrated below:
Fig.3
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2010.06 - Rev.A
Technical Note
BH7881EFV
●Application circuit
Fig.4 Minimum external components example
Fig.5 Maximum external components example
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7/9
2010.06 - Rev.A
Technical Note
BH7881EFV
●Operation Notes
1. Numbers and data in entries are representative design values and are not guaranteed values of the items.
2. Although ROHM is confident that the example application circuit reflects the best possible recommendations, be sure to
verify circuit characteristics for your particular application. Modification of constants for other externally connected circuits
may cause variations in both static and transient characteristics for external components as well as this Rohm IC. Allow for
sufficient margins when determining circuit constants.
3. Absolute maximum ratings
Use of the IC in excess of absolute maximum ratings, such as the applied voltage or operating temperature range (Topr),
may result in IC damage. Assumptions should not be made regarding the state of the IC (short mode or open mode) when
such damage is suffered. A physical safety measure, such as a fuse, should be implemented when using the IC at times
where the absolute maximum ratings may be exceeded.
4. GND potential
Ensure a minimum GND pin potential in all operating conditions. Make sure that no pins are at a voltage below the GND at
any time, regardless of whether it is a transient signal or not.
5. Thermal design
Perform thermal design, in which there are adequate margins, by taking into account the permissible dissipation (Pd) in
actual states of use.
6. Short circuit between terminals and erroneous mounting
Pay attention to the assembly direction of the ICs. Wrong mounting direction or shorts between terminals, GND, or other
components on the circuits, can damage the IC.
7. Operation in strong electromagnetic field
Using the ICs in a strong electromagnetic field can cause operation malfunction.
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2010.06 - Rev.A
Technical Note
BH7881EFV
●Ordering part number
B
H
7
Part No.
8
8
1
Part No.
E
F
V
-
Package
EFV: HTSSOP-B24
E
2
Packaging and forming specification
E2: Embossed tape and reel
HTSSOP-B24
7.8±0.1
(MAX 8.15 include BURR)
(5.0)
1.0±0.2
0.53±0.15
(3.4)
1
0.325
Tape
Embossed carrier tape (with dry pack)
Quantity
2000pcs
Direction
of feed
E2
The direction is the 1pin of product is at the upper left when you hold
( reel on the left hand and you pull out the tape on the right hand
)
12
1PIN MARK
+0.05
0.17 -0.03
S
0.08±0.05
0.85±0.05
1.0MAX
+6°
4° −4°
13
5.6±0.1
7.6±0.2
24
0.65
0.08 S
+0.05
0.24 -0.04
0.08
1pin
M
Reel
(Unit : mm)
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Direction of feed
∗ Order quantity needs to be multiple of the minimum quantity.
2010.06 - Rev.A
Datasheet
Notice
Precaution on using ROHM Products
1.
Our Products are designed and manufactured for application in ordinary electronic equipments (such as AV equipment,
OA equipment, telecommunication equipment, home electronic appliances, amusement equipment, etc.). If you
(Note 1)
, transport
intend to use our Products in devices requiring extremely high reliability (such as medical equipment
equipment, traffic equipment, aircraft/spacecraft, nuclear power controllers, fuel controllers, car equipment including car
accessories, safety devices, etc.) and whose malfunction or failure may cause loss of human life, bodily injury or
serious damage to property (“Specific Applications”), please consult with the ROHM sales representative in advance.
Unless otherwise agreed in writing by ROHM in advance, ROHM shall not be in any way responsible or liable for any
damages, expenses or losses incurred by you or third parties arising from the use of any ROHM’s Products for Specific
Applications.
(Note1) Medical Equipment Classification of the Specific Applications
JAPAN
USA
EU
CHINA
CLASSⅢ
CLASSⅡb
CLASSⅢ
CLASSⅢ
CLASSⅣ
CLASSⅢ
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[a] Installation of protection circuits or other protective devices to improve system safety
[b] Installation of redundant circuits to reduce the impact of single or multiple circuit failure
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[h] Use of the Products in places subject to dew condensation
4.
The Products are not subject to radiation-proof design.
5.
Please verify and confirm characteristics of the final or mounted products in using the Products.
6.
In particular, if a transient load (a large amount of load applied in a short period of time, such as pulse. is applied,
confirmation of performance characteristics after on-board mounting is strongly recommended. Avoid applying power
exceeding normal rated power; exceeding the power rating under steady-state loading condition may negatively affect
product performance and reliability.
7.
De-rate Power Dissipation (Pd) depending on Ambient temperature (Ta). When used in sealed area, confirm the actual
ambient temperature.
8.
Confirm that operation temperature is within the specified range described in the product specification.
9.
ROHM shall not be in any way responsible or liable for failure induced under deviant condition from what is defined in
this document.
Precaution for Mounting / Circuit board design
1.
When a highly active halogenous (chlorine, bromine, etc.) flux is used, the residue of flux may negatively affect product
performance and reliability.
2.
In principle, the reflow soldering method must be used; if flow soldering method is preferred, please consult with the
ROHM representative in advance.
For details, please refer to ROHM Mounting specification
Notice - GE
© 2014 ROHM Co., Ltd. All rights reserved.
Rev.002
Datasheet
Precautions Regarding Application Examples and External Circuits
1.
If change is made to the constant of an external circuit, please allow a sufficient margin considering variations of the
characteristics of the Products and external components, including transient characteristics, as well as static
characteristics.
2.
You agree that application notes, reference designs, and associated data and information contained in this document
are presented only as guidance for Products use. Therefore, in case you use such information, you are solely
responsible for it and you must exercise your own independent verification and judgment in the use of such information
contained in this document. ROHM shall not be in any way responsible or liable for any damages, expenses or losses
incurred by you or third parties arising from the use of such information.
Precaution for Electrostatic
This Product is electrostatic sensitive product, which may be damaged due to electrostatic discharge. Please take proper
caution in your manufacturing process and storage so that voltage exceeding the Products maximum rating will not be
applied to Products. Please take special care under dry condition (e.g. Grounding of human body / equipment / solder iron,
isolation from charged objects, setting of Ionizer, friction prevention and temperature / humidity control).
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1.
Product performance and soldered connections may deteriorate if the Products are stored in the places where:
[a] the Products are exposed to sea winds or corrosive gases, including Cl2, H2S, NH3, SO2, and NO2
[b] the temperature or humidity exceeds those recommended by ROHM
[c] the Products are exposed to direct sunshine or condensation
[d] the Products are exposed to high Electrostatic
2.
Even under ROHM recommended storage condition, solderability of products out of recommended storage time period
may be degraded. It is strongly recommended to confirm solderability before using Products of which storage time is
exceeding the recommended storage time period.
3.
Store / transport cartons in the correct direction, which is indicated on a carton with a symbol. Otherwise bent leads
may occur due to excessive stress applied when dropping of a carton.
4.
Use Products within the specified time after opening a humidity barrier bag. Baking is required before using Products of
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The proper names of companies or products described in this document are trademarks or registered trademarks of
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© 2014 ROHM Co., Ltd. All rights reserved.
Rev.002
Datasheet
General Precaution
1. Before you use our Pro ducts, you are requested to care fully read this document and fully understand its contents.
ROHM shall n ot be in an y way responsible or liabl e for fa ilure, malfunction or acci dent arising from the use of a ny
ROHM’s Products against warning, caution or note contained in this document.
2. All information contained in this docume nt is current as of the issuing date and subj ect to change without any prior
notice. Before purchasing or using ROHM’s Products, please confirm the la test information with a ROHM sale s
representative.
3.
The information contained in this doc ument is provi ded on an “as is” basis and ROHM does not warrant that all
information contained in this document is accurate an d/or error-free. ROHM shall not be in an y way responsible or
liable for an y damages, expenses or losses incurred b y you or third parties resulting from inaccur acy or errors of or
concerning such information.
Notice – WE
© 2014 ROHM Co., Ltd. All rights reserved.
Rev.001