lc75397e Sanyo Semiconductor Corporation, lc75397e Datasheet - Page 20

• Manufacturer Part Number: lc75397e
• Description: Single Chip Electronic Volume And Tone Control System
• Manufacturer: Sanyo Semiconductor Corporation

2. F1/F2 band circuits
This section presents the equivalent circuit and the formulas used to calculate the external resistor and capacitor values to
provide a center frequency of 148 Hz.
• F1/F2 band equivalent circuit
• Sample calculation
Specifications: Center frequency: f0 = 148 Hz
(1) Determine R2 from the specification that G
(2) Determine C from the specification that the center frequency f0 = 148 Hz.
(3) Determine Q.
G
R2 = ———————— = ——————— = 11979.7 12 k
f0 = ————————
C = —————— = ——————————— = 0.0431 10
Q = ————— · ————— = ———————— = 1.039
+10dB
Gain at maximum boost: G
Assume R1 = 51.8 k and C1 = C2 = C.
2 f0 R1R2
C · C · R1
2 (10
2 f R1R2C1C2
= 20 LOG
2C
1
G+10dB/20
R1
1
10
– 1)
R1R2CC
(
1 + ——
2
1
2R2
R1
148 51800 12000
+10dB
2 (3.162 – 1)
)
+10dB
51800
1
2 51800 12000
= 10 dB
= 10 dB.
LC75397E
51800
–6
0.044 µF
No. 6108-20/26