Analog Input / BTL Output
Class-D Speaker Amplifier
BD5423AEFS
●Description
BD5423AEFS is a 17W + 17W stereo class-D power amplifier IC, developed for space-saving and low heat-generation
applications such as low-profile TV sets. The IC employs state-of-the-art Bipolar, CMOS, and DMOS (BCD) process
technology that eliminates turn-on resistance in the output power stage and internal loss due to line resistances up to an
ultimate level. With this technology, the IC has achieved high efficiency of 90% (10W + 10W output with 8 load), which is
the top class in the industry. The IC, in addition, employs a compact back-surface heat radiation type power package to
achieve low power consumption and low heat generation and eliminates necessity of installing an external radiator, up to a
total output of 34W. This product satisfies both needs for drastic downsizing, low-profile structures and powerful, highquality playback of the sound system.
●Features
1) A high efficiency of 90% (10W + 10W output with 8 load),
which is the highest grade in the industry and low heat-generation.
2) An output of 17W + 17W (12V, with 4 load) is allowed without an external heat radiator.
3) Driving a lowest rating load of 4 is allowed.
4) Pop noise upon turning power on/off and power interruption has been reduced.
5) High-quality audio muting is implemented by soft-switching technology.
6) An output power limiter function limits excessive output to speakers.
7) High-reliability design provided with built-in protection circuits against high temperatures,
against VCC shorting and GND shorting, against reduced-voltage, and against applying DC voltage to speaker.
8) A master/slave function allowing synchronization of multiple devices reduces beat noises.
9) Adjustment of internal PWM sampling clock frequencies (250kHz to 400kHz)
allows easy protective measures against unwanted radio emission to AM radio band.
10) A compact back-surface heat radiation type power package is employed.
HTSSOP-A44 (5mm × 7.5mm × 1.0mm, pitch 0.8mm )
●Absolute Maximum Ratings
A circuit must be designed and evaluated not to exceed absolute maximum rating in any cases and even momentarily, to
prevent reduction in functional performances and thermal destruction of a semiconductor product and secure useful life and
reliability.
The following values assume Ta =25℃. For latest values, refer to delivery specifications.
Parameter SymbolRatings
Supply voltageVCC+20V
Power dissipationPd
Input voltage for signal pinVIN-0.2 ~ +7.2VPin 1, 44 (Note 1)
UnitConditions
Pin 7, 8, 15, 16, 29, 30, 37, 38, 40
(Note 1, 2)
2.0W(Note 3)
4.5W(Note 4)
No.10075EBT02
Input voltage for control pinVCONT-0.2 ~ Vcc+0.2VPin 20, 24 (Note 1)
Input voltage for clock pinVOSC-0.2 ~ +7.2VPin 23 (Note 1)
Operating temperature rangeTopr-40 ~ +85℃
Storage temperature rangeTstg-55 ~ +150℃
Maximum junction temperatureTjmax+150℃
(Note 1) A voltage that can be applied with reference to GND (pins 11, 12, 33, 34, and 43)
(Note 2) Pd and Tjmax=150℃ must not be exceeded.
(Note 3) 70mm × 70mm × 1.6mm FR4 One-sided glass epoxy board (Back copper foil 0%) installed.
If used under Ta=25℃ or higher, reduce 16mW for increase of every 1℃. The board is provided with thermal via.
(Note 4) 70mm × 70mm × 1.6mm FR4 Both-sided glass epoxy board (Back copper foil 100%) installed.
If used under Ta=25℃ or higher, reduce 36mW for increase of every 1℃. The board is provided with thermal via.
The following values assume Ta =25℃. Check for latest values in delivery specifications.
Parameter SymbolRatings Unit Conditions
Technical Note
Supply voltageVCC
Load resistanceRL 4 ~ 16 (Note 5)
(Note 5) Pd should not be exceeded.
●Electrical Characteristics
Except otherwise specified T
For latest values, refer to delivery specifications.
Parameter SymbolLimits
Whole circuit
Circuit current 1
(Sampling mode)
Circuit current 2
(Muting mode)
Control circuit
“H” level input voltageVIH2.3~12VSDX, MUTEX, MS
“L” level input voltageVIL0~0.8VSDX, MUTEX, MS
Audio circuit
Voltage gainGV28dBPO = 1W
a = 25℃, VCC = 12V, fIN = 1kHz, Rg = 0, RL = 8、MUTEX="H", MS="L"
ICC125mAWith no signal
ICC210mAMUTEX = “L”
+10~+16.5
UnitConditions
V Pin 7, 8, 15, 16, 29, 30, 37, 38, 40
Maximum output power 1 (Note 6)PO110WTHD+N = 10%, RL = 8
Maximum output power 2 (Note 6)PO217WTHD+N = 10%, RL = 4
Total harmonic distortion (Note 6)THD 0.1%PO = 1W, BW=20Hz~20kHz
CrosstalkCT 85dBPO = 1W, Rg = 0, BW = IHF-A
Output noise voltage
(Sampling mode)
Residual noise voltage
(Muting mode)
Internal sampling clock frequencyFOSC250kHzMS = “L” (In master operation)
(Note 6) The rated values of items above indicate average performances of the device, which largely depend on circuit layouts, components,
and power supplies. The reference values are those applicable to the device and components directly installed on a board specified by us.
1. About absolute maximum ratings
If an applied voltage or an operating temperature exceeds an absolute maximum rating, it may cause destruction of a
device. A result of destruction, whether it is short mode or open mode, is not predictable. Therefore, provide a physical
safety measure such as fuse, against a special mode that may violate conditions of absolute maximum ratings.
2. About power supply line
As return of current regenerated by back EMF of output coil happens, take steps such as putting capacitor between
power supply and GND as a electric pathway for the regenerated current. Be sure that there is no problem with each
property such as emptied capacity at lower temperature regarding electrolytic capacitor to decide capacity value. If the
connected power supply does not have sufficient current absorption capacity, regenerative current will cause the voltage
on the power supply line to rise, which combined with the product and its peripheral circuitry may exceed the absolute
maximum ratings. It is recommended to implement a physical safety measure such as the insertion of a voltage clamp
diode between the power supply and GND pins.
3. Potential of GND (11, 12, 33, 34, and 43 pins)
Potential of the GND terminal must be the lowest under any operating conditions.
4. About thermal design
Perform thermal design with sufficient margins, in consideration of maximum power dissipation Pd under actual operating
conditions. This product has an exposed frame on the back of the package, and it is assumed that the frame is used with
measures to improve efficiency of heat dissipation. In addition to front surface of board, provide a heat dissipation pattern
as widely as possible on the back also.
A class-D power amplifier has heat dissipation efficiency far higher than that of conventional analog power amplifier and
generates less heat. However, extra attention must be paid in thermal design so that a power dissipation Pdiss should not
exceed the maximum power dissipation Pd.
Maximum power dissipation
Power dissipation
jmax
Pd
aj
1
PPOdiss
W
W 1-
Tjmax: Maximum temperature junction = 150[℃]
Ta: Operating ambient temperature [℃] θja: Package thermal resistance [℃/W]
Po: Output power [W]
η: Efficiency
Ta-T
5. About operations in strong electric field
Note that the device may malfunction in a strong electric field.
6. Thermal shutdown (TSD) 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. Accordingly, do not use this circuit function to protect a customer's electrical
appliance.
7. About shorting between pins and installation failure
Be careful about direction and displacement of an LSI when installing it onto the board. Faulty installation may destroy
the LSI when the device is energized. In addition, a foreign matter getting in between LSI pins, pins and power supply,
and pins and GND may cause shorting and destruction of the LSI.
8. About power supply startup and shutdown
When starting up a power supply, be sure to place the MUTEX pin (pin 20) at “L” level. When shutting down a power
supply also, be sure to place the pin at “L” level. Those processes reduce pop noises generated upon turning on and off
the power supply. In addition, all power supply pins must be started up and shut down at the same time.
9. About WARNING output pin (pin 18) and ERROR output pin (pin 19)
A WARNING flag is output from the WARNING output pin upon operation of the high-temperature protection function and
under-voltage protection function. And an ERROR flag is output from the ERROR output pin upon operation of VCC/GND
shorting protection function and speaker DC voltage applying protection function. These flags are the function which the
condition of this product is shown in. The use which aimed at the protection except for this product is prohibition.
10. About N.C. pins (pins 21 and 22)
The N.C. (Non connection) pins are not connected with an internal circuit. Leave the pins open or connect them to GND.
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