STK400-070 Sanyo Semiconductor Corporation, STK400-070 Datasheet - Page 4

• Manufacturer Part Number: STK400-070
• Description: af Power Amplifier (40W+40W+40W)
• Manufacturer: Sanyo Semiconductor Corporation

External Component Description
C8, C9, C28, C29
R8, R9, R28, R29
C1, C11, C21
C2, C12, C22
C3, C13, C23
C5, C15, C25
R1, R11, R21
R2, R12, R22
R3, R13, R23
R4, R14, R24
R5, R15, R25
R6, R16, R26
L1, L2, L3
C6, C7
Input coupling capacitors.
For DC blocking. Since capacitor reactance becomes larger at lower frequencies, the output noise can be adversely affected by signal source
resistance-dependent 1/f noise. In this case, a lower reactance value should be chosen. In order to remove pop noise at power-on, larger
values of capacitance should be chosen for C1 and C11, which determine the input time constant, and smaller values for C3, C13 and C23 in
the NF circuit.
Input filter capacitors.
These, together with R1, R11 and R21, form filters to reduce high-frequency noise.
NF capacitors.
These determine the low-side cut-off frequency.
Large values should be chosen for C3, C13 and C23 to maintain voltage gain at low frequencies. However, because this would tend to
increase the shock noise at power-on, values larger than absolutely necessary should be avoided.
Oscillation prevention capacitors.
Mylar capacitors are recommended for their excellent thermal and frequency characteristics.
Oscillation prevention capacitors.
These should be inserted as close as possible to the IC supply pins to reduce supply impedance and hence provide stable IC operation.
Electrolytic capacitors are recommended.
Decoupling capacitors.
These, together with R8, R9, R28 and R29, form time constant circuits that remove shock noise and ripple voltage from the supply, preventing
any noise being coupled to the inputs.
Input filter resistors.
Input bias resistors.
These are used to bias the input pins at zero potential. The input impedance is largely determined by this resistance.
Voltage-gain VG setting resistors.
VG = 40dB is recommended using R3, R13, R23 = 560 , and R4, R14, R24 = 56k . Gain adjustments are best made using R3, R13 and
R23. If gain adjustments are made using R4, R14 and R24, then set R2, R12, R22 = R4, R14, R24 to maintain V
Oscillation prevention resistors.
Oscillation prevention resistors.
The power dissipated in these resistors is dependent on the frequency, as given below.
where f is the output signal frequency upper limit.
Ripple filter resistors.
P
consideration both the function they perform as predriver transistor limiting resistors during load short circuits and the peak current that flows
through them when charging C8, C9, C28 and C29.
Oscillation prevention coils.
These correct the phase difference caused by capacitive loads and increase stability against oscillation.
P R6 (R16, R26)
f
O
L
max, ripple rejection and supply power-on shock noise are all affected by this resistance. These resistors should be chosen taking into
=
--------------------------------------------------------------------------------------------
2
C 3 C 13 C 23
=
------------------------------------------------------------------------------------------------- -
1 2 f
1
R 3 R 13 R 23
C5 C15 C25
(
V
CC
,
max
STK400-070
)
+
2
R6 R 16 R 26
(
,
)
2
R 6 R 16 R 26
(
,
)
N
balance stability.
No. 4598—4/9