BH3541F / BH3544F
Optical disc ICs
Headphone amplifier for CD-ROMs
BH3541F / BH3544F
The BH3541F and BH3544F are digital-source dual headphone amplifiers. The BH3541F has a fixed gain of 0dB and
the BH3544F has a fixed gain of 6dB so that external gain setting is unnecessary. Both the BH3541F and BH3544F have
internal mute functions so that prevention of the popping sound when power is turned on and off is greatly simplified.
Also, these ICs are equipped with thermal shutdown circuits to prevent damage from short circuits.
Product name
BH3541F
!!!!
BH3544F
Applications
Devices that use the headphone output from CD-ROMs, CDs, MDs, personal computers, notebook computers,
camcorders, etc.
Fixed gain
0dB
6dB
Features
!!!!
1) Internal mute function to prevent popping sounds when the power is turned on and off.
2) Built-in thermal shutdown circuit (150°C) to prevent damage to the IC if a short circuit occurs.
3) Compact SOP8 pin package.
Absolute maximum ratings
!!!!
Parameter Symbol Limits Unit
Applied voltage V
Power dissipation Pd 450 mW
Operating temperature Topr
Storage temperature Tstg
∗Reduced by 4.5mW for each increase in Ta of 1°C over 25°C.
Recommended operating conditions
!!!!
Parameter
Power supply voltage
(Ta = 25°C)
Max
7.0 V
∗
−25 ~ +75
−55 ~ +125 °C
(Ta = 25°C)
Symbol Min. Typ. Max. Unit
CC
V
2.8
−
6.5 V
°C
Optical disc ICs
Block diagram
!!!!
V
TSD
BH3541F / BH3544F
CC
OUT2 BIAS IN2
BIAS
0dB
(6dB)
+
+
0dB
(6dB)
MUTE
5678
180k
(90k)
180k
(90k)
OUT1
21
MUTE IN1 GND
3 4
( ) The values in parenthesis are for the BH3544F.
Optical disc ICs
Pin descriptions
!!!!
BH3541F / BH3544F
Pin No. Pin name Internal equivalent circuit
1
OUT1
Pin voltage
I / O
O 2.1V
V
CC
1
7
2
OUT2
MUTE
O 2.1V
(V
CC=
0.1V
I
5V)
7
10k
V
CC
2
(When open)
190k
V
CC
3
IN1
I 2.1V
Function
Output pin
Mute control pin
(set to low for prevention of
popping noise when power
is turned on and off).
Operating : High
Muting : Low (open)
Input pin
3
5
IN2
I 2.1V
CC
=5V)
(V
5
2.1V
6
4
8I
BIAS
GND
CC
V
I / O
I −
(V
CC
=5V)
6
−
180k
BIAS
V
CC
Bias pin
(the external 47µF
capacitor also serves as the
anti-pop time constant,
therefore make the proper
60k
BIAS
60k
considerations be changing
it).
Optical disc ICs
Electrical characteristics
!!!!
BH3544F : V
Parameter
Quiescent current
Mute pin control voltage
Voltage gain
Voltage gain difference between channels
Total harmonic distortion
Rated output 1
Rated output 2
Output noise voltage
Channel separation
Mute attenuation
Ripple rejection
Measurement circuit
!!!!
32
16
(unless otherwise noted, Ta = 25°C, VCC = 5.0V, RL = 32Ω, BH3541F : VIN = 0dBV,
BH3541F
BH3544F
SW7
1
2
330µ
+
V
V
7AC
IN
= −6dBV, and f = 1kHz)
Symbol Min. Typ. Max. Unit
I
Q
TM
V
VC
G
∆G
VC
THD
P
O1
P
O2
V
NO
CS
ATT
RR 50 57
4 7 10 mA
0.3 0.7 1.6 V
−2
2dB
4608dB
0
31
62
90
80
0.5
−
−
−85
−
−
−0.5
−
25
50
−
82
70
0.02 0.1 %
−93
−
47µ
+
BH3541F / BH3544F
Conditions
V
IN
=0Vrms
−
−
−
SW5
1
2
−
V
IN
2
dB
BW=20~20kHz
mW
mW
dBV
dB
dB
dB
L
=32Ω, THD < 0.1%
R
L
=16Ω, THD < 0.1%
R
BW=20~20kHz, Rg=0Ω
Rg=0Ω
Rg=0Ω
RR
=100Hz, VRR=−20dBV
f
1µ
SW8B
V
RR
A
12
32
16
CV
CC
+
V
CC
IQ
SW8A
V
CC
SW1
1
2
V
10µ
330µ
+
V
1AC
OUT2 BIAS IN2
0dB
(6dB)
TSD
OUT1
V
TM
0dB
(6dB)
MUTE
21
MUTE IN1 GND
5678
BIAS
180k
(90k)
+
180k
(90k)
+
3 4
1µ
( ) The values in parenthesis are for the BH3544F.
SW3
1
2
V
IN
1
Fig.1
Optical disc ICs
Measurement conditions
!!!!
Signal
SW1
I
Q
1 1 1 1 2 OFF IQ
V
TM
−−−−−− − −
VC
G
∆G
THD
P
P
V
CS
ATT
RR
∗( ) The values in parenthesis are for the BH3544F.
1 2 2 1 2 ON V1AC, V2AC
−−−−−− −
VC
12212ON
O1
12212ON
O2
22222ON
NO
11112ON
1112211122ON
12212ON
11111ON
SW3
SW table
SW5
SW7
SW8A
SW8B
ON
BH3541F / BH3544F
Monitor Conditions
IN
1/2=0dBV (VIN1/2=−6dBV),
IN
1/2=0dBV (VIN1/2=−6dBV),
IN
1/2=0dBV (VIN1/2=−6dBV),
IN
1/2=0dBV (VIN1/2=−6dBV),
IN
2=0dBV (VIN2=−6dBV),
IN
1=0dBV (VIN1=−6dBV),
=
0.3VB
=−20dBV, fRR=100Hz
V1AC, V2AC
V1AC, V2AC
V1AC, V2AC
V1AC, V2AC
V1AC, V2AC
V1AC, V2AC
V1AC, V2AC
V1AC, V2AC
f=1kHz, V
VTM=1.6V
GVC1−GVC2
fin=1kHz, V
VTM=1.6V
fin=1kHz, V
VTM=1.6V
fin=1kHz, V
VTM=1.6V
fin=1kHz, V
VTM=1.6V
fin=1kHz, V
VTM=1.6V
fin=1kHz, VIN1/2=0dBV (VIN1/2=−6dBV),
VTM
RR
V
−
−
Circuit operation
!!!!
Rising edge timing
CC
V
OUT
VMUTE
ARise period Play period Rise periodA
CB
A : MUTE period (use with MUTE = Low to prevent the popping noise when the power is turned on and off).
B : MUTE release time (used to prevent the popping noise at the release of MUTE with the external C2 and R2,
and therefore possesses a time constant, so be careful of the timing).
C : MUTE start time (also possesses a time constant like the MUTE release time).
Optical disc ICs
Application example
!!!!
CC
V
BH3541F / BH3544F
330µ
+
47µ
0dB
(6dB)
0dB
(6dB)
+
BIAS
5678
180k
(90k)
+
+
V
+
CC
OUT2 BIAS IN2
TSD
MUTE
180k
(90k)
1µ
V
IN
2
3 4
1µ
( ) The values in parenthesis are for the BH3544F.
IN
1
V
VMUTE
H : Active
L : Mute
330µ
21
OUT1
+
100k
MUTE IN1 GND
1µ
Fig.2
Explanation of external components
!!!!
(1) Input coupling capacitor (C3 and C5)
Determined by the low-band cut-off frequency. Since the input impedance for this IC is 180kΩ, it can be determined by
the formula below, but take into consideration the fluctuations, ambient temperature, etc. (a multi-layered ceramic
capacitor is recommended).
C3 (C5) = 1 / ( 2π × 180kΩ × f )
(2) BIAS capacitor (C6)
47µF when V
CC
= 5V, and 33µF when VCC = 3V. If the capacitance is lowered too much, the electrical characteristics
will be adversely affected and popping noise may occur. Therefore, take the sufficient considerations before changing
these values.
(3) MUTE pin for anti-pop measures (R2 and C2)
Possesses an impedance of 190kΩ with respect to GND, so if R2 is increased too much, the MUTE mode may
become unable to be released.
(4) Output coupling capacitor (C1 and C7)
Determined by the low-band cutoff frequency. As the output load resistance value R
L
(assuming that for output
protection or current limiting, a resistor RX will be inserted), it can be determined by the formula below.
C1 (C7) = 1 / ( 2π × ( R
L
+ RX ) × f )
(5) Input gain adjustment resistor (R3 and R4) (for BH3544F only)
Input gain adjustment can by performed by external resistors R3 and R4. The desired gain can be set by the formula
given below.
VC
G
= 6 + 20log ( 90kΩ / ( 90kΩ + R3 ) ) [dB]
BH3541F / BH3544F
Optical disc ICs
Operation notes
!!!!
The application example is recommended by ROHM, but before use in your application, be sure to carefully confirm
electrical characteristics.
Also, for use with different circuit constants for the external circuits, be sure to leave a sufficient margin for fluctuations in
characteristics in the external components and ROHM ICs in not only the static characteristics, but also the transient
characteristics as well.
Electrical characteristic curves
!!!!
(mA)
Q
QUIESCENT CURRENT : I
10
Ta=25°C
9
RL=32Ω
8
7
6
5
4
3
2
1
0
204
SUPPLY VOLTAGE : V
MUTE : OFF
MUTE : ON
6810
5
Ta=25°C
RL=32Ω
4
(V)
BIAS
3
2
1
BIAS DC VOLTAGE : V
00
CC
(V)
204
SUPPLY VOLTAGE : V
6810
CC
5
4
3
2
1
(V)
(V)
O
OUTPUT DC VOLTAGE : V
10
Ta=25
°C
RL=32Ω
0
V
CC
=5V
−10
IN
=0dBV
V
f=1kHz
−20
−30
−40
−50
−60
−70
OUTPUT VOLTAGE : VOUT (dBV)
−80
−90
0.40 0.8
MUTE CONTROL VOLTAGE : VTM (V)
1.2 1.6 2
Fig.3 Quiescent current vs.
power supply voltage
8
6
4
2
0
−2
−4
−6
VOLTAGE GAIN : GVC (dB)
−8
−10
−12
10
100
1k 10k
FREQUENCY : F (HZ)
Fig.6 Voltage gain vs. frequency
BH3544F
BH3541F
Ta=25°C
RL=32Ω
V
IN=0dBV
V
CC=5V
100k
Fig.5
Fig.4 Pin DC current vs.
power supply voltage
10
Ta=25°C
RL=32Ω
V
CC
=5V
1
f=10kH
0.001
TOTAL HARMONIC DISTORTION : THD (%)
0.1
0.01
−40
−30
OUTPUT VOLTAGE :
f=1kH
−20 −10 10
Fig.7 Total harmonic distortion vs.
output voltage ( )
Z
Z
f=100H
0
VO (dBV)
10
Z
Ta=25
RL=32Ω
V
CC
1
0.1
0.01
0.001
TOTAL HARMONIC DISTORTION : THD (%)
−40
Fig.8 Total harmonic distortion vs.
output voltage ( )
Output voltage vs.
MUTE control voltage
°C
=3V
f=10kH
Z
f=1kH
Z
f=100H
Z
−30
−20 −10 10
OUTPUT VOLTAGE : V
O
(dBV)
0
Optical disc ICs
BH3541F / BH3544F
10
Ta=25
°C
RL=16Ω
V
CC=5V
1
0.1
0.01
0.001
TOTAL HARMONIC DISTORTION : THD (%)
−40
f=10kHZ
f=1kHZ
−30
−20 −10 10
OUTPUT VOLTAGE
f=100HZ
0
: VO (dBV)
Fig.9 Total harmonic distortion vs.
output voltage ( )
MUTE ATTENUTION : ATT (dB)
100
90
80
70
60
50
40
30
20
10
0
10
100
FREQUENCY : f (H
C-BIAS:47µF
C-BIAS:33µF
C-BIAS:100µF
V
TM
=
R
L
=
32Ω
V
IN
=
0dBV
V
CC
1k 10k 100k
=
Z
)
OPEN
5V
10
Ta=25
°C
RL=16Ω
V
CC
=3V
1
0.1
0.01
0.001
TOTAL HARMONIC DISTORTION : THD (%)
−40
f=10kH
f=1kH
f=100H
Z
−30
−20 −10 10
OUTPUT VOLTAGE : V
Fig.10 Total harmonic distortion vs.
output voltage ( )
80
70
60
50
40
30
20
RIPPLE REJECTION : RR (dB)
10
0
10
100
FREQUENCY :
Z
Z
0
O
(dBV)
Ta=25
°C
VRR=−20dBV
R
L
=32Ω
Rg=0Ω
CC
=5V
V
1k 10k 100k
f (HZ)
120
100
80
60
40
20
CHANNEL SEPARATION : CS (dB)
0
10
100
1k 10k 100k
FREQUENC
Fig.11 Channel separation vs. frequency
100
90
80
70
60
50
40
30
20
RIPPLE REJECTION : RR (dB)
10
0
204
SUPPLY VOLTAGE : V
Ta=25
°C
RL=32Ω
Rg=0Ω
V
CC
=5V
Y : f (HZ)
Ta=25°C
VRR=−20dBV
R
L
=32Ω
Rg=0Ω
RR
=100H
Z
f
6810
CC
(V)
Fig.12 MUTE attenuation vs. frequency
External dimensions
!!!!
(Units : mm)
5.0±0.2
85
±0.3
±0.2
4.4
6.2
41
0.1
±
1.5
0.11
1.27
0.4±0.1
SOP8
0.3Min.
Fig.13 Ripple rejection vs. frequency
0.15±0.1
0.15
Fig.14 Ripple rejection vs.
power supply voltage
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