BH3541F_09 ROHM [Rohm], BH3541F_09 Datasheet - Page 6

• Manufacturer Part Number: BH3541F_09
• Description: Stereo Headphone Amplifiers
• Manufacturer: ROHM [Rohm]

●Application circuit
●Description of external components.
●Notes for use
© 2009 ROHM Co., Ltd. All rights reserved.
BH3541F, BH3544F, BH3547F, BH3548F
www.rohm.com
1) Input coupling capacitors (C3, C5)
2) Bias capacitor (C6)
3) Mute pin pop noise countermeasures (R2, C2)
4) Output coupling capacitors (C1, C7)
5) Input gain adjustment resistances (R3, R5) (BH3544F,BH3547F)
1) Numbers and data in entries are representative design values and are not guaranteed values of the items.
2) Although we are confident in recommending the sample application circuits, carefully check their characteristics further
3) Absolute maximum ratings
When input gain is not accommodated, these resistors have no use.
These are determined according to the lower cutoff frequency fc. Moreover, since lowering the capacitance can cause
the occurrence of pop noise, when changing this, determine it after adequate checking.
Since the input impedance of the BH3541F is 180kΩ and that of the BH3544F,BH3547F,BH3548F is 90kΩ, these are
found by the expressions below, although drift, temperature characteristics, and other considerations are necessary.
(Layered ceramic capacitors are recommended.)
When VCC=5V, 47μF is recommended. Since lowering the capacitance too much can cause worsening of electrical
characteristics or the occurrence of pop noise, when changing this, determine it after checking this adequately.
Since the BH3541F,BH3544F,BH3548F has an impedance of 190kΩ against GND and the BH3547F has 200kΩ, it may
be impossible to cancel mute mode if R2 is made too large.
These are determined by the lower cutoff frequency. If R
put in for output protection or current restriction), these are found by the expression below.
Externally attached resistances (R3, R5) make input gain adjustment possible. The gain found by the expression
below can be set.
when using them. When modifying externally attached component constants before use, determine them so that they
have sufficient margins by taking into account variations in externally attached components and the Rohm LSI, not only
for static characteristics but also including transient characteristics.
If applied voltage, operating temperature range, or other absolute maximum ratings are exceeded, the LSI may be
damaged. Do not apply voltages or temperatures that exceed the absolute maximum ratings. If you think of a case in
which absolute maximum ratings are exceeded, enforce fuses or other physical safety measures and investigate how
not to apply the conditions under which absolute maximum ratings are exceeded to the LSI.
C3(C5)=1/(2π×180kΩ×fc) [BH3541F]
C3(C5)=1/(2π× 90kΩ×fc)
C1(C7)=1/(2π×(R
G
VC
=6+20log(90kΩ/(90kΩ+R3[R5])) [dB]
H : Active
L : Mute
V
VMUTE
CC
C8
10
µ
L
+Rｘ)× fc)
+
C1
330 µ
330 µ
C7
+
+
[BH3544Ｆ,BH3547F,BH3548F]
R2
100k
V
1
CC
OUT1
TSD
8
OUT2
MUTE
2
Fig. 15
MUTE
7
C2
1 µ
6/8
(6dB)
(6dB)
0dB
0dB
L
BIAS
is the output load resistance (assuming a resistance R
3
( ) are BH3544F, BH3547F, BH3548F values.
+
BIAS
IN1
R3
6
C6
47 µ
IN2
4
5
GND
(90k)
180k
R5
180k
(90k)
C3
1 µ
C5
1 µ
V
V
IN
IN
Technical Note
1
2009.07 - Rev.A
2
X
is