367
Audio ICs
1.5V / 15mW dual power amplifier
BA5152F
The BA5152F is a dual-channel power amplifier designed for 1.5V headphone stereos. The circuit consists of a power
supply circuit, mute circuit, bias circuit, and two amplifier circuits. T o simplify assembly, the gain is fixed, so external nega-
tive-feedback components are not required.
Applications
1.5V headphone Hi-Fi stereos
Features
1) High output. POUT = 15mW (RL = 16Ω).
2) Small “pop” noise.
3) Mute circuit terminal provided.
4) Terminals provided for radiation countermeasures.
5) Good ripple rejection ratio.
6) Few external components required.
7) Good low-voltage characteristics.
8) Built-in power switch circuit.
Block diagram
Absolute maximum ratings (Ta = 25C)
368
Audio ICs BA5152F
Recommended operating conditions (Ta = 25C)
Electrical characteristics (unless otherwise noted, Ta = 25C, VCC = 1.5V, f= 1kHz and RL = 16Ω)
Measurement circuit
369
Audio ICs BA5152F
Application example
Application board patterns Application board component layout
370
Audio ICs BA5152F
Complete application example circuit
Circuit description
(1) Power supply block
The BA5152F has an internal power switch, so the VCC
terminal (pin 9) connects directly to the power source. Pin
13 is the power switch, and if it is left open, no bias current
flows in the circuit and the IC will not operate.
(2) Mute circuit block
When pin 13 is connected to VCC, the IC starts up, but the
mute circuit operates to suppress a “pop” sound from be-
ing generated. The time constant of the power-on mute
circuit is determined by the capacitor connected between
pins 14 and 15. It is also possible to force the mute circuit
to operate by connecting pin 16 to VCC. There is no time
constant in this case.
371
Audio ICs BA5152F
(3) Bias block
The components connected to pins 2, 3, and 4 set the
bias point and VODC. When pin 2 is open circuit, and VCC
= 1.25V, the output pin VODC voltage is internally set to
1/2VCC. By connecting a resistor to pin 2 and changing
the voltage divider ratio, it is possible to vary VODC.
Pins 3 and 4 are shorted and connected to earth via an
electrolytic capacitor to generate the bias point. When a
33µF component is used, it is possible to obtain 45dB of
ripple rejection. This can be improved if pins are indepen-
dently grounded through capacitors.
(4) Amplifier block
The amplifier circuits have a fixed gain of GV = 21dB. The
negative-feedback circuits are on the chip, and the
ground point of the negative-feedback circuit uses the
bias point as its reference, so connect the input poten-
tiometer to the bias point pins (3 and 4). Connect bypass
capacitors to the output pin to prevent oscillation. When
the IC is used in sets containing an AM radio, it is possible
to reduce unnecessary radiation from the power amplifi-
ers by connecting CR circuits to pins 6 and 11.
Electrical characteristics curves (Ta = 25C)
External dimensions (Units: mm)
372
Audio ICs BA5152F
Appendix
Appendix1-Rev1.0
The products listed in this document are designed to be used with ordinary electronic equipment or devices
(such as audio visual equipment, office-automation equipment, communications devices, electrical
appliances and electronic toys).
Should you intend to use these products with equipment or devices which require an extremely high level of
reliability and the malfunction of with would directly endanger human life (such as medical instruments,
transportation equipment, aerospace machinery, nuclear-reactor controllers, fuel controllers and other
safety devices), please be sure to consult with our sales representative in advance.
Notes
No technical content pages of this document may be reproduced in any form or transmitted by any
means without prior permission of ROHM CO.,LTD.
The contents described herein are subject to change without notice. The specifications for the
product described in this document are for reference only. Upon actual use, therefore, please request
that specifications to be separately delivered.
Application circuit diagrams and circuit constants contained herein are shown as examples of standard
use and operation. Please pay careful attention to the peripheral conditions when designing circuits
and deciding upon circuit constants in the set.
Any data, including, but not limited to application circuit diagrams information, described herein
are intended only as illustrations of such devices and not as the specifications for such devices. ROHM
CO.,LTD. disclaims any warranty that any use of such devices shall be free from infringement of any
third party's intellectual property rights or other proprietary rights, and further, assumes no liability of
whatsoever nature in the event of any such infringement, or arising from or connected with or related
to the use of such devices.
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otherwise dispose of the same, no express or implied right or license to practice or commercially
exploit any intellectual property rights or other proprietary rights owned or controlled by
ROHM CO., LTD. is granted to any such buyer.
Products listed in this document use silicon as a basic material.
Products listed in this document are no antiradiation design.
About Export Control Order in Japan
Products described herein are the objects of controlled goods in Annex 1 (Item 16) of Export Trade Control
Order in Japan.
In case of export from Japan, please confirm if it applies to "objective" criteria or an "informed" (by MITI clause)
on the basis of "catch all controls for Non-Proliferation of Weapons of Mass Destruction.
