ROHM BD5424EFS Technical data

Middle Power Class-D Speaker Amplifiers

Analog Input / BTL Output
Class-D Speaker Amplifier

BD5424EFS

●Description

BD5424EFS is a 20W + 20W 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 91% (10W + 10W output with 8Ω load), which is the top class in
the industry. 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 40W.
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 91% (10W + 10W output with 8Ω load), which is the highest grade in the industry and low heat-generation.

2) An output of 20W + 20W (17V, with 8Ω load) is allowed without an external heat radiator.

3) Driving a lowest rating load of 3.6Ω 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 (350kHz to 500kHz) 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.

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

No.10075EBT04

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 × 1.6mm FR4 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 × 1.6mm FR4 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.

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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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2010.05 - Rev.B

BD5424EFS

●Operating Conditions

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

Technical Note

Parameter

Supply voltage VCC +10 ~ +18 V Pin 7, 8, 15, 16, 29, 30, 37, 38, 40

Minimum load resistance RL 3.6 Ω (Note 5)

(Note 5) Pd should not be exceeded.

●Electrical Characteristics

Except otherwise specified T
For latest values, refer to delivery specifications.

Parameter

Whole circuit

Circuit current 1 (Sampling mode) ICC1 30 mA With no signal

Circuit current 2 (Muting mode) ICC2 12 mA MUTEX = “L”

Control circuit

“H” level input voltage VIH 2.3 ~ 12 V SDX, MUTEX, MS

“L” level input voltage VIL 0 ~ 0.8 V SDX, MUTEX, MS

Audio circuit

Symbol Ratings Unit Conditions

a = 25℃, VCC = 12V, fIN = 1kHz, Rg = 0Ω, RL = 8Ω, MUTEX="H", MS="L", SDX="H".

Symbol Limits Unit Conditions

Voltage gain GV 28 dB PO = 1W

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

Maximum output power 2 (Note 6) PO2 20 W Vcc=17V, 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) VNO 80 µVrms Rg = 0Ω, BW = IHF-A

Residual noise voltage (Muting mode) VNOM 35 µVrms Rg = 0Ω, BW = IHF-A, MUTEX = “L”

Mute Attenuation Gvm 98 dB Po =1W, BW =IHF-A, MUTEX = “L”

Internal sampling clock frequency FOSC 350 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.

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2/17

2010.05 - Rev.B

BD5424EFS

r

r

●Electrical characteristic curves (Reference data)

(1) Under Stereo Operation (R

L=8Ω)

100

Vcc=12V
RL=8Ω

10

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

Fig. 1 THD+N － Output powe

40

35

30

25

20

15

10

VOLTAGE GAIN (dB)

Vcc=12V

L

=8Ω

R
Po=1W
L=33µH
C=0.47µF
Cｇ=0.1µF

5

0

10 100 1000 10000 100000

FREQUENCY (Hz)

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

-20

-40

0

Vcc=12V

L

=8Ω

R
fin=1kHz
BW=20～20kHz

-60

CROSSTALK (dB)

-80

-100

0.001 0.01 0.1 1 10 100
OUTPUT POWER (W)

Fig. 5 Crosstalk - Output powe

Technical Note

100

Vcc=12V

L

=8Ω

10

1

THD+ N (%)

0.1

0.01
10 100 1000 10000 100000

FREQUENCY (Hz)

Fig. 2 THD+N － Frequency

0

-20

-40

-60

CROSSTALK (dB)

-80

-100
10 100 1000 10000 100000

FREQUENCY (Hz)

25

20

RL=8Ω
fin=1kHz

THD=10%

15

10

5

OUTPUT POWER (W)

0

8 101214161820

VCC (V)

Fig. 6 Output power - Power supply voltage

R
Po=1W
BW=20～20kHz

Vcc=12V

L

=8Ω

R
Po=1W
BW=20～20kHz

THD=1%

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3/17

2010.05 - Rev.B

BD5424EFS

r

r

r

r

●Electrical characteristic curves (Reference data) – Continued

100

90
80
70
60
50
40
30

EFFICIENCY (%)

20
10

Vcc=10V

L

=8Ω

R
fin=1kHz

0

0 5 10 15 20

OUTPUT POWER (W/ch)

Fig. 7 Efficiency - Output powe

100

90
80
70
60
50
40
30

EFFICIENCY (%)

Vcc=18V

L

R

=8Ω

fin=1kHz

20
10

0

0 5 10 15 20 25

OUTPUT POWER (W/ch)

Fig. 9 Efficiency - Output powe

100

90

RL=8Ω

Without signal

80

無信号時

70
60
50
40

ICC (mA)

30
20

Sampling

Mute

10

0

81012141618

VCC (V)

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

Technical Note

100

90
80
70
60
50
40
30

EFFICIENCY (%)

20
10

0

0 5 10 15 20

OUTPUT POWER (W/ch)

Fig. 8 Efficiency - Output powe

3

Vcc=18V

2

Vcc=10V

ICC (A)

1

0

0 5 10 15 20 25 30 35 40 45 50

Fig. 10 Current consumption - Output powe

0

-20

-40

-60

-80

-100

NOISE FFT (dBV)

-120

-140
10 100 1000 10000 100000

Vcc=12V

TOTAL OUTPUT POWER (W)

Vcc=12V

L

R

=8Ω

Without signal

無信号時
BW=20～20kHz

FREQUENCY (Hz)

Vcc=12V

L

R

=8Ω

fin=1kHz

RL=8Ω
fin=1kHz

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4/17

2010.05 - Rev.B

BD5424EFS

●Electrical characteristic curves (Reference data) – Continued

MUTEX

Pin 20

TM

Pin 26

10V/div

5V/div

Vcc=12V
R

=8

L

Po=500mW
fin=500Hz

MUTEX

Pin 20

Ω

TM

Pin 26

Technical Note

10V/div

5V/div

Vcc=12V
R

L

Po=500mW
fin=500Hz

=8

Ω

Speaker

2V/div

output

10msec/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

5V/div

5V/div

2V/div

output

20msec/div

Fig. 15 Wave form on Instantaneous Power Interruption

(20msec / div)

Soft Clip

Speaker

output

Soft Clip

5V/div

Vcc=12V

=8

R

L

Ω

Po=500mW
fin=3kHz

Vcc=12V
R

=8

L

Po=5W
THD+n=10%
fin=1kHz
R2=91k

R3=22k

Speaker

2V/div

output

10msec/div

VCCA

VHOLD

Pin 27

TM

Pin 26

Speaker

5V/div

5V/div

Vcc=12V
R
Po=500mW

fin=3k Hz

2V/div

output

2msec/div

Fig. 16 Wave form on Instantaneous Power Interruption

(2msec / div)

Ω

Ω
Ω

=8

L

Ω

Fig. 17 Wave form on Output Power Limiter function

(Po = 5W)

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200μsec/div

5/17

2010.05 - Rev.B

BD5424EFS

r

r

r

●Electrical characteristic curves (Reference data) – Continued

(2)Under Stereo Operation (R

30

RL=6Ω

25

fin=1kHz

20

15

10

5

OUTPUT POWER (W)

0

8 101214161820

Fig. 18 Output power - Power supply voltage

100

90
80
70
60
50
40
30

EFFICIENCY (%)

20
10

0

0 5 10 15 20 25

OUTPUT POWER (W/ch)

Fig. 19 Efficiency - Output powe

100

90
80
70
60
50
40
30

EFFICIENCY (%)

20
10

0

0 5 10 15 20 25 30

OUTPUT POWER (W/ch)

Fig. 21 Efficiency - Output powe

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

L=6Ω)

THD=10%

VCC (V)

Vcc=10V

L

=6Ω

R
fin=1kHz

Vcc=18V

L

=6Ω

R
fin=1kHz

100

90
80
70
60
50
40
30

EFFICIENCY (%)

20
10

0

0 5 10 15 20 25

OUTPUT POWER (W/ch)

Fig. 20 Efficiency - Output power

4

3

Vcc=12V

Vcc=10V

2

ICC (A)

1

0

0 5 10 15 20 25 30 35 40 45 50 55 60

TOTAL OUTPUT POWER (W)

Fig. 22 Current consumption - Output powe

Technical Note

Vcc=12V
R
fin=1kHz

Vcc=18V

RL=6Ω
fin=1kHz

L

=6Ω

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6/17

2010.05 - Rev.B