BU26156RFS Datasheet, PDF (89/95 Pages) Rohm – Monoraul MIC Input with ALC

BU26156RFS
Datasheet
Cautions on use
1) Absolute Maximum Ratings
An excess in the absolute maximum ratings, such as supply voltage, temperature range of operating conditions, etc.,
can break down devices, thus don’t exceed the absolute maximum ratings of supply voltage, temperature. If any special
mode exceeding the absolute maximum ratings is assumed, consideration should be given to take physical safety
measures including the use of fuses, etc.
2) GND voltage
Make setting of the potential of the GND terminal so that it will be maintained at the minimum in any operating state.
3) Short circuit between terminals and erroneous mounting
In order to mount ICs on a set PCB, pay thorough attention to the direction and offset of the ICs. Erroneous mounting
can break down the ICs. Furthermore, if a short circuit occurs due to foreign matters entering between terminals or
between the terminal and the power supply or the GND terminal, the ICs can break down.
4) Operation in strong electromagnetic field
Be noted that using ICs in the strong electromagnetic field can malfunction them.
5) Thermal design
If use speaker amplifier function, please consider power dissipation by an actual using status, and perform the thermal
design which have a margin enough. If an input signal is made excessive in the state with insufficient heat dissipation,
desired output power may not only be securable, but the thermal shutdown may operate.
6) Thermal shutdown
This IC has the thermal shutdown circuit. If the thermal shutdown operates, speaker output terminal and Headphone
Output terminal will stop in the open state(high impedance state).The thermal shutdown is only a function for
suspending the output operation of IC to the last at the time of the thermal run-away under the abnormal condition in
which chip temperature(Tjmax) exceeded 170 degrees. It is a circuit to protect IC, and the purpose is not offering
protection and a guarantee of the set.
7) Short protection of output terminals
This IC has the short protect function for output terminals. If the short protect function operates, output terminal will be
latched and stop in the open state(high impedance state).After a stop, even if a short state is removed, it does not return
to normal operation automatically. Please once write speaker amplifier enable register to make it return.
8) Operating condition
Operating voltage and operating temperature are ranges which perform basic function. Electrical characteristics and
absolute maximum rating are not guaranteed in full voltage range or full temperature range.
9) Electrical characteristics specification
Each audio characteristic specification, such as limit output power, total harmonic distortion, the maximum gain, an ALC
limit level, and an ALC release level, shows the standard performance of the device, and depends for it on board layout /
use parts / power supply part greatly.
Typical specification value is a value when a device and each parts are directly mounted in the board of Rohm's
standard.
10) Power supply
Since the speaker L power supply (SPLVDD) and the speaker R power supply (SPRVDD) are shorted inside IC, please
use them as a same power supply.
Moreover, large peak current rushes into a power supply line at the time of ClassD speaker amplifier use.
The audio characteristic is affected by the value of a power supply decoupling capacitor, and layout.
The power supply decoupling capacitor should be layouted (1uF or more) with sufficiently low ESR (equivalent series
resistance) to most close of IC terminal.
Moreover, in the design of a board pattern, the wiring of a power supply / GND line should become low impedance. In
that case, even if digital power supply and analog power supply are same potential, please devide the digital power
pattern and the analog power pattern and reduce a surroundings lump of the digital noise to the analog power supply by
the common impedance of a wiring pattern.
Please take the same pattern design into consideration also about a GND line. Moreover, while inserting a capacitor
between power supply-GND terminals about all the power supply terminals of LSI, and please determine the value of
capacitor after sufficient confirmation that there is no problem in the characteristics of capacitors to be used (a capacity
omission happens at low temperature) in the case of electrolytic capacitors use.
11) External capacitor
In order to use a ceramic capacitor as the external capacitor, determine the constant with consideration given to a
degradation in the nominal capacitance due to DC bias and changes in the capacitance due to temperature, etc.
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TSZ22111・15・001
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TSZ02201-0V1V0E502570-1-2
Jul.1.2014 Rev.001