Technical Note
20/21
BD5471MUV
www.rohm.com
2010.06 - Rev.A
© 2010 ROHM Co., Ltd. All rights reserved.
●Notes for use
(1) Absolute maximum ratings
This IC may be damaged if the absolute maximum ratings for the applied voltage, temperature range, or other
parameters are exceeded. Therefore, avoid using a voltage or temperature that exceeds the absolute maximum ratings.
If it is possible that absolute maximum ratings will be exceeded, use fuses or other physical safety measures and
determine ways to avoid exceeding the IC's absolute maximum ratings.
(2) GND terminal’s potential
Try to set the minimum voltage for GND terminal’s potential, regardless of the operation mode.
(3) Shorting between pins and mounting errors
When mounting the IC chip on a board, be very careful to set the chip's orientation and position precisely. When the
power is turned on, the IC may be damaged if it is not mounted correctly. The IC may also be damaged if a short occurs
(due to a foreign object, etc.) between two pins, between a pin and the power supply, or between a pin and the GND.
(4) Operation in strong magnetic fields
Note with caution that operation faults may occur when this IC operates in a strong magnetic field.
(5) Thermal design
Ensure sufficient margins to the thermal design by taking in to account the allowable power dissipation during actual use
modes, because this IC is power amp. When excessive signal inputs which the heat dissipation is insufficient condition, it
is possible that thermal shutdown circuit is active.
(6) Thermal shutdown circuit
This product is provided with a built-in thermal shutdown circuit. When the thermal shutdown circuit operates, the output
transistors are placed under open status. The thermal shutdown circuit is primarily intended to shut down the IC avoiding
thermal runaway under abnormal conditions with a chip temperature exceeding Tjmax = +150℃, and is not intended to
protect and secure an electrical appliance.
(7) Load of the output terminal
This IC corresponds to dynamic speaker load, and doesn't correspond to the load except for dynamic speakers.
(8) The short protection of the output terminal
This IC is built in the short protection for a protection of output transistors. When the short protection is operated, output
terminal become Hi-Z condition and is stopped with latch. Once output is stopped with latch, output does not recover
automatically by canceling the short-circuiting condition. The condition of stopping with latch is cancelled, when power
supply or mute signal is turned off and turned on again.
(9) Operating ranges
The rated operating power supply voltage range (VDD=+4.5V ~ +5.5V) and the rated operating temperature range
(Ta=-40℃ ~ +85℃) are the range by which basic circuit functions is operated. Characteristics and rated output power are
not guaranteed in all power supply voltage ranges or temperature ranges.
(10) Electrical characteristics
Electrical characteristics show the typical performance of device and depend on board layout, parts, power supply.
The standard value is in mounting device and parts on surface of ROHM’s board directly.
(11) Maximum output power
When stereo inputs at RL=4Ω, maximum output power may not achieve up to typical value because the device heats.
Ensure sufficient margins to the thermal design to get larger output power.
(12) Power decoupling capacitor
Because the big peak current flows through the power line, the class-D amplifier has an influence on the Audio
characteristic by the capacitance value or the arrangement part of the power decoupling capacitor.
(13) Power supply
Use single power supply, because power supplies (4,10,15,21pin) of audio amplifier and regulator are shorted inside.
Audio
