lc7527e Sanyo Semiconductor Corporation, lc7527e Datasheet - Page 9

• Manufacturer Part Number: lc7527e
• Description: Graphic Equalizer Controller
• Manufacturer: Sanyo Semiconductor Corporation

External Component Value Calculations
The external capacitors required for each band in the LC7527E are the structural elements in semiconductor inductors
(simulated inductors). The remainder of this section presents the equivalent circuits and the formulas used to determine
the center frequencies.
1. Semiconductor Inductor Equivalent Circuit
2. Calculation Example
3. Sample Values for C1 and C2
The LC7527E provides circuits with differing constants for the low and high bands.
Specifications: 1) Center frequency: Fo = 63 Hz
• Derive the sharpness Qo of the semiconductor inductor itself.
• Derive C1.
• Derive C2.
Qo =
C1 = 1/2 FoR1Qo ≠ 0.953 (µF)
C2 = Qo/2 FoR2 ≠ 0.034 (µF)
frequency
Fo (Hz)
Center
16000
1000
2500
6300
160
400
63
(R1 + R4)
R1
2) Q at maximum boost: Q
0.953 µ
0.377 µ
0.151 µ
0.060 µ
0.024 µ
9563 p
3765 p
C1
(F)
Q
+12 dB
0.034 µ
0.014 µ
5390 p
2156 p
3422 p
1348 p
862 p
≈ 4.064
C2
(F)
See the internal equivalent circuit figure for R4.
+12 dB
= 1.05
LC7527E
No. 4466-9/11