ROHM BD5426EFS Technical data

Middle Power Class-D Speaker Amplifiers

Analog Input / BTL Output
Class-D Speaker Amplifier

BD5426EFS

●Description

BD5426EFS is a 10W + 10W stereo class-D power amplifier IC, developed for space-saving and low heat-generation
applications such as low-profile TV sets. The IC employs state-of-the-art Bipolar, CMOS, and DMOS (BCD) process
technology that eliminates turn-on resistance in the output power stage and internal loss due to line resistances up to an
ultimate level. With this technology, the IC has achieved high efficiency of 87% (9W + 9W output with 8Ω load). The IC, in
addition, employs a compact back-surface heat radiation type power package to achieve low power consumption and low
heat generation and eliminates necessity of installing an external radiator, up to a total output of 20W. This product satisfies
both needs for drastic downsizing, low-profile structures and powerful, high-quality playback of the sound system.

●Features

1) A high efficiency of 87% (9W + 9W output with 8Ω load), which is the highest grade in the industry and low heat-generation.

2) An output of 10W + 10W (13V, with 8Ω load) is allowed without an external heat radiator.

3) Driving a lowest rating load of 6Ω is allowed.

4) Pop noise upon turning power on/off and power interruption has been reduced.

5) High-quality audio muting is implemented by soft-switching technology.

6) An output power limiter function limits excessive output to speakers.

7) High-reliability design provided with built-in protection circuits against high temperatures, against VCC shorting and
GND shorting, against reduced-voltage, and against applying DC voltage to speaker.

8) A master/slave function allowing synchronization of multiple devices reduces beat noises.

9) Adjustment of internal PWM sampling clock frequencies (250kHz to 400kHz) allows easy protective measures
against unwanted radio emission to AM radio band.

10) A compact back-surface heat radiation type power package is employed.

HTSSOP-A44(5mm × 7.5mm × 1.0mm, pitch 0.8mm )

●Absolute maximum ratings

A circuit must be designed and evaluated not to exceed absolute maximum rating in any cases and even momentarily, to prevent
reduction in functional performances and thermal destruction of a semiconductor product and secure useful life and reliability.

No.10075EBT05

The following values assume Ta =25℃. For latest values, refer to delivery specifications.

Parameter

Supply voltage VCC +20 V

Power dissipation Pd

Input voltage for signal pin VIN -0.2 ~ +7.2 V Pin 1, 44 (Note 1)

Input voltage for control pin VCONT -0.2 ~ Vcc+0.2 V Pin 20, 24 (Note 1)

Input voltage for clock pin VOSC -0.2 ~ +7.2 V Pin 23 (Note 1)

Operating temperature range Topr -40 ~ +85 ℃

Storage temperature range Tstg -55 ~ +150 ℃

Maximum junction temperature Tjmax +150 ℃

(Note 1) A voltage that can be applied with reference to GND (pins 11, 12, 33, 34, and 43)
(Note 2) Pd and Tjmax=150℃ must not be exceeded.
(Note 3) 70mm × 70mm × 1.6mmFR4 One-sided glass epoxy board (Back copper foil 0%) installed.
If used under Ta=25℃ or higher, reduce 16mW for increase of every 1℃. The board is provided with thermal via.
(Note 4) 70mm × 70mm × 1.6mmFR4 Both-sided glass epoxy board (Back copper foil 100%) installed.
If used under Ta=25℃ or higher, reduce 36mW for increase of every 1℃. The board is provided with thermal via.

Symbol Ratings Unit Conditions

Pin 7, 8, 15, 16, 29, 30, 37, 38, 40
(Note 1, 2)

2.0 W (Note 3)

4.5 W (Note 4)

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1/16

2010.05 - Rev.B

BD5426EFS

●Operating conditions

The following values assume Ta =25℃. Check for latest values in delivery specifications.

Technical Note

Parameter

Supply voltage VCC +10 ~ +16.5 V Pin 7, 8, 15, 16, 29, 30, 37, 38, 40

Load resistance RL 6 ~ 16 Ω (Note 5)

(Note 5) Pd should not be exceeded.

●Electrical characteristics

Except otherwise specified Ta = 25℃, VCC = 12V, fIN = 1kHz, Rg = 0Ω, RL = 8Ω,MUTEX="H", MS="L"
For latest values, refer to delivery specifications.

Parameter Symbol Limits Unit Conditions

Whole circuit

Circuit current 1 (Sampling mode) I

Circuit current 2 (Muting mode) I

Control circuit

“H” level input voltage V

“L” level input voltage V

Audio circuit

Voltage gain GV 28 dB PO = 1W

Symbol Ratings Unit Conditions

25 mA With no signal

CC1

10 mA MUTEX = “L”

CC2

2.3 ~ 12 V SDX, MUTEX, MS

IH

0 ~ 0.8 V SDX, MUTEX, MS

IL

Maximum output power 1 (Note 6) PO1 9 W THD+N = 10%

Maximum output power 2 (Note 6) PO2 10 W Vcc = 13V, THD+N = 10%

Total harmonic distortion (Note 6) THD 0.1 % PO = 1W, BW=20Hz ~ 20kHz

Crosstalk CT 85 dB PO = 1W, Rg = 0Ω, BW = IHF-A

Output noise voltage
(Sampling mode)

Residual noise voltage
(Muting mode)

Internal sampling clock frequency FOSC 250 kHz MS = “L” (In master operation)

(Note 6) The rated values of items above indicate average performances of the device, which largely depend on circuit layouts, components,

and power supplies. The reference values are those applicable to the device and components directly installed on a board specified by us.

VNO 80 µVrms Rg = 0Ω, BW = IHF-A

VNOM 1 µVrms Rg = 0Ω, BW = IHF-A, MUTEX = “L”

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2/16

2010.05 - Rev.B

BD5426EFS

●Electrical characteristic curves (Reference data)

(1)Under Stereo Operation (R

100

Vcc=12V

=8Ω

R

L

10

BW=20～20kHz

L=8Ω)

Technical Note

100

Vcc=12V
R

L

=8Ω

10

Po=1W
BW=20～20kHz

1

THD+N (%)

0.1

0.01

0.001 0.01 0.1 1 10 100

OUTPUT POWER (W)

6kHz

1kHz

100Hz

1

THD+N (%)

0.1

0.01
10 100 1000 10000 100000

FREQUENCY (Hz)

Fig. 1 THD+N － Output power Fig. 2 THD+N － Frequency

35

30

25

20

15

10

VOLTAGE GAIN (dB)

5

0

10 100 1000 10000 100000

Vcc=12V
R

=8Ω

L

Po=1W
L=33µH
C=0.47µF
Cｇ=0.1µF

FREQUENCY (Hz)

0

Vcc=12V

L

=8Ω

-20

-40

-60

CROSST ALK (dB)

-80

-100
10 100 1000 10000 100000

FREQUENCY (Hz)

R
Po=1W
BW=20～20kHz

Fig. 3 Voltage gain - Frequency Fig. 4 Crosstalk - Frequency

0

Vcc=12V

L

R

-20

-40

=8Ω
fin=1kHz
BW=20～20kHz

20

RL=8Ω
fin=1kHz

15

THD=10%

10

-60

CROSSTALK (dB)

-80

-100

0.001 0.01 0.1 1 10 100
OUTPUT POWER (W)

Fig. 5 Crosstalk - Output power Fig. 6 Output power - Power supply voltage

5

OUTPUT POWER (W)

0

8 1012141618

V

(V)

CC

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3/16

2010.05 - Rev.B

BD5426EFS

●Electrical characteristic curves (Reference data) – Continued

100

90
80
70
60
50
40
30

EFFICIENCY (%)

20
10

Vcc=10V

L

R

=8Ω

fin=1kHz

0

0 5 10 15 20

OUTPUT POWER (W/ch)

Fig. 7 Efficiency - Output power Fig. 8 Efficiency - Output power

100

90
80
70
60
50
40
30

EFFICIENCY (%)

20
10

Vcc=16.5V

L

R

=8Ω

fin=1kHz

0

0 5 10 15 20

OUTPUT POWER (W/ch)

Technical Note

100

90
80
70
60
50
40
30

EFFICIENCY (%)

20
10

0

0 5 10 15 20

OUTPUT POWER (W/ch)

3

2

Vcc=10V

(A)

CC

I

1

0

0 5 10 15 20 25 30 35 40

TOTAL OUTPUT POWER (W)

Vcc=12V

Vcc=12V

L

=8Ω

R
fin=1kHz

Vcc=16.5V

RL=8Ω
fin=1kHz

Fig. 9 Efficiency - Output power Fig. 10 Current consumption - Output power

100

RL=8Ω

90

Without signal

無信号時

80
70
60
50

(mA)

CC

40

I

30
20
10

Sampling

Mute

0

8 1012141618

(V)

V

CC

Fig. 11 Current consumption - Power supply voltage Fig. 12 FFT of Output Noise Voltage

0

-20

-40

-60

Vcc=12V

L

R

=8Ω

Without signal

無信号時
BW=20～20kHz

-80

-100

NOISE FFT (dBV)

-120

-140
10 100 1000 10000 100000

FREQUENCY (Hz)

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4/16

2010.05 - Rev.B

BD5426EFS

%

●Electrical characteristic curves (Reference data) – Continued

Technical Note

MUTEX

Pin 20

TM

Pin 26

Speaker

Output

10V/div

5V/div

2V/div

10msec/div

Vcc=12V

=8

R

L

Po=500mW
fin=500Hz

M

UTEX

Pin 20

Ω

TM

P

in 26

Speaker

Output

10msec/div

10V/div

5V/div

2V/div

Fig. 13 Wave form when Releasing Soft-mute Fig. 14 Wave form when Activating Soft-mute

VCCA

VHOLD

Pin 27

TM

Pin 26

Speaker

Output

20msec/div

5V/div

5V/div

2V/div

Vcc=12V
R

=8

L

Po=500mW
fin=3kHz

Fig. 15 Wave form on Instantaneous Power Interruption

(20msec / div)

VCCA

VHOLD

Pin 27

Ω

TM

Pin 26

Speaker

Output

5V/div

5V/div

2V/div

2msec/div

Fig. 16 Wave form on Instantaneous Power Interruption

(2msec / div)

Vcc=12V
R

=8

L

Ω

Po=500mW
fin=500Hz

Vcc=12V
R

=8

L

Ω

Po=500mW

fin=3kHz

Speaker

Output

Soft Clip

5V/div

Soft Clip

200μsec/div

Vcc=12V
R
Po=5W
THD+n=10
fin=1kHz
R2=91k

R3=22k

Fig. 17 Wave form on Output Power Limiter function

(Po = 5W)

=8

L

Ω

Ω
Ω

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5/16

2010.05 - Rev.B

BD5426EFS

●Electrical characteristic curves (Reference data) – Continued

(2)Under Stereo Operation(R

L=6Ω)

25

RL=6Ω

20

15

fin=1kHz

THD=10%

Technical Note

10

5

OUTPUT POWER (W)

0

8 1012141618

V

(V)

CC

Fig. 18 Output power - Power supply voltage

100

90
80
70
60
50
40
30

EFFICIENCY (%)

20
10

Vcc=10V

L

=6Ω

R
fin=1kHz

0

0 5 10 15 20 25

100

90
80
70
60
50
40
30

EFFICIENCY (%)

20
10

0

0 5 10 15 20 25

OUTPUT POWER (W/ch)

OUTPUT POWER (W/ch)

Vcc=12V

L

R

=6Ω

fin=1kHz

Fig. 19 Efficiency - Output power Fig. 20 Efficiency - Output power

100

90
80
70
60
50
40
30

EFFICIENCY (%)

20
10

Vcc=16.5V

L

R

=6Ω

fin=1kHz

0

0 5 10 15 20 25

OUTPUT POWER (W/ch)

Fig. 21 Efficiency - Output power Fig. 22 Current consumption - Output power

Dotted lines of the graphs indicate continuous output power to be obtained on musical signal source or by installing
additional heat sinks.

4

Vcc=16.5V

3

Vcc=12V

2

ICC (A)

1

0

Vcc=10V

RL=6Ω
fin=1kHz

0 5 10 15 20 25 30 35 40 45 50

TOTAL OUTPUT POWER (W)

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6/16

2010.05 - Rev.B