LA4725_09 SANYO [Sanyo Semicon Device], LA4725_09 Datasheet - Page 4

• Manufacturer Part Number: LA4725_09
• Description: 2-channel 30W BTL Audio Power Amplifier
• Manufacturer: SANYO [Sanyo Semicon Device]

Pin Voltages
V CC = 13.2V, with 5V applied to STBY through a 10kΩ resistor, R L = 4Ω, Rg = 0
External Components
IC Internal Characteristics and Notes
C1 and C4: Input capacitors. A value of 2.2µF is recommended. Determine the polarity based on the DC potential of
C2
C3
C5
C6, C7, C8, and C9 :
C10
R1
1. Standby function
2. Muting function
3. Impulse noise improvements
Pin voltage
Pin voltage
Pin name
Pin name
Pin No.
Pin No.
• Pin 4 is the standby switch. A voltage of 2.5V or
• If a voltage of over 12V will be applied as the
• Pin 5 connects the capacitor that determines the starting time to prevent impulse noise. It can also be used to mute
• While the LA4725 achieves a low level of impulse noise, if even further reductions in impulse noise at power
higher must be applied through an external resistor to
turn the amplifier on.
standby mode switching voltage, use the following
formula to determine the value of R1 so that the
current entering at pin 4 remains under 500µA.
the amplifier output by shorting pin 5 to ground. When this function is used, the recovery time depends on C3.
on/off (and when switching into or out of standby mode) a 0.47µF capacitor may be inserted between pin 7 and the
PRE GND pin (pin 3). (Pin 7 is the output amplifier bias pin. Since the ability to withstand shorting the output pins
to V CC or ground is reduced for supply voltages over 16V if the pin 7 capacitance is large, we recommend a value
of 0.47µF or lower for this capacitor.)
R1 =
: Decoupling capacitor (ripple filter)
: Sets the amplifier starting time, which will be approximately 0.6 seconds for a value of 33µF. The starting
: Power-supply capacitor
: Impulse noise reduction capacitor. A value of 0.47µF is recommended. Caution is required when selecting
: Standby switch current limiting resistor. A value of 10kΩ is recommended when a voltage in the range 2.5 to
Oscillation prevention capacitors. Use polyester film capacitors (Mylar capacitors) with excellent
characteristics. (Note that the series resistors R2, R3, R4, and R5 are used in conjunction with these
capacitors to achieve stable amplifier operation.) A value of 0.1µF is recommended.
the circuit connected directly to the LA4725 front end. Note that the low band response can be adjusted by
varying f L with the capacitors C1 and C4.
time is proportional to the value of this capacitor, and can be set to any desired value.
the value for this capacitor, since increasing its value influences the operation of the circuits that protect
against shorting the amplifier output pins to V CC or to ground when higher V CC voltages (approximately
16V or higher) are used.
12V will be applied as the standby switching voltage. Note that this resistor is not optional: it must be included.
<applied voltage> − 1.4
+OUT2
1.53V
5.70V
IN1
1
8
500µA
−OUT2
5.65V
5.70V
DC
2
9
− 10kΩ
PRE-GND
PWR-GN
0V
10
0V
3
LA4725
+OUT1
STBY
3.25V
5.70V
11
4
Applied standby
voltage
ON TIME
PWR-GN
2.32V
12
0V
5
Pin 4 Internal Equivalent Circuit
R1
500µA or lower
−OUT1
1.53V
5.70V
IN2
13
6
4
About 1.4V
(2V BE )
10kΩ
2.14V
13.2V
POP
V CC
14
7
No.6631-4/8