lv4993m Sanyo Semiconductor Corporation, lv4993m Datasheet - Page 6

• Manufacturer Part Number: lv4993m
• Description: For Portable Audio Equipment Monaural Btl Power Amplifier
• Manufacturer: Sanyo Semiconductor Corporation

Cautions for use
1. Input coupling capacitor (C3)
2. BTL voltage gain
3. Pin 3 capacitor (C4)
4. Capacitor for power supply line (C1, C2)
5. Standby pin (pin 2)
C3 is an input coupling capacitor, and it has aimed at the DC cutting. However, please set it in consideration of the
cutoff frequency when you decide the capacitance value so that the high-pass filter may be composed by this capacitor
(C3) and input resistance (R1), and the bass frequency signal may attenuate.
The cutoff frequency is shown by the next formula.
Moreover, this capacitor influences a pop noise at start-up. Please note it enough so that the charging time to the
capacitor may become long when the value is enlarged, and the pop noise level may grow.
The voltage gain of the first amplifier is decided depending on the ratio of resistance R1 and R2.
Therefore, the BTL voltage gain:
It is shown by the above-mentioned calculating formula. Please set the BTL voltage gain within the range from 0 to
26dB.
C4 is a capacitor for the ripple filter. It is a purpose to compose the low-pass filter of internal resistance
(100kΩ+450kΩ) and C4, to reduce the power supply ripple element, and to improve the ripple elimination factor.
Please operate the automatic pop noise reduction circuit by using the standing up transition response characteristic of
3rd pin voltage (standard voltage), and design in IC in consideration of a pop noise at the time of start-up growing
when the C3 capacity value is reduced to hasten the start-up speed.
Bypass capacitor (C2) has aimed at the high frequency aphaeresis that cannot be removed with the power supply
capacitor (C1: Chemical capacitor). This capacity must arrange as much as possible near IC, and use the ceramic
capacitor with good high-frequency property.
It is also possible to bring it together in the ceramic capacitor of one 2.2μF when a steady power supply is used. Please
enlarge the capacity value of power supply capacitor (C1) when the power supply line is comparatively unstable.
By controlling the standby pin, the mode changeover can be made between standby and operation modes. The series
resistance (R3:1kΩ or more) is recommended to be inserted might receive the influence of a digital noise from CPU
though it is possible to control with the output port of CPU directly.
Please suppress the impressed voltage to become a static test mode (heat protection circuit operation check mode)
when 3V or more is impressed to 2nd pin within 3V. Moreover, it is also possible to synchronize with the power
supply and to use the pin as shown in Figure 1 when the standby function is not used. Please set the value of series
resistance (R3) so that 2nd pin voltage may become 3V or less.
Standby mode ⇒ V2 = 0 to 0.3V
Operation mode ⇒ V2 = 1.6 to 3V
Current (I 2 ) that flows in 2nd pin can be calculated by the next formula.
fc =
Vg=20 * log(R2/R1) (dB)
VgBTL=6+20 * log(R1/R2) (dB)
I 2 =
2π*C3*R1
7*10
1
R3+30000
-6
+(V CC −0.7)
LV4993M
V CC
R3
STBY
V CC
Fig. 1
7
2
No.A1962-6/13