CXA3010 データシートの表示（PDF） - Sony Semiconductor

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CXA3010

Read/Write Amplifier (with Built-in Filters) for FDDs

Sony Semiconductor 

CXA3010Q

Description of Operation

(1) Read system

Preamplifier

The preamplifier amplifies input signals. The voltage gain can be switched between 39dB and 45dB, using

Pin 20. In addition, an additional 3dB boost in the voltage gain is possible by setting Pin 8 low.

Filters

The filters differentiate the signals amplified by the preamplifier. The high-band noise components are

attenuated by the low-pass filter. The filters can be switched among four modes, depending on the settings of

Pins 8, 9 and 18. In 1M/outer track mode, the peak frequency fO1 is set by external resistor RF.

fO for the other three modes is switched by the internal settings of the IC, with fO1 used as a reference (1.00).

Active filter block

19 Preamplifier output A

17 Preamplifier output B

Preamplifier output

BPF

LPF

Secondary

fOB = 1.2 × fC

Q = 0.577

Tertiary

fc: variable

HPF

Primary

fCH = 5kHz

15

Amp

14

Gain : 8dB

Filter output A

Filter output B

The center frequency fOB of the BPF is fixed to 1.2 times the cutoff frequency fO of the LPF. The LPF

characteristics are set to Chebyshev (1dB ripple) for 1.6M, 2M/inner track mode only, and to Butterworth for all

other modes.

Pin8

OTF

H

L

H

L

H

L

Pin9

XHD

H

H

H

H

L

L

Pin18

X360

H

H

L

L

X

X

LPF characteristics

1M/outer track: Butterworth

1M/inner track: Butterworth

1.6M/outer track: Butterworth

1.6M/inner track: Chebyshev 1dB ripple

2M/outer track: Butterworth

2M/inner track: Chebyshev 1dB ripple

fo ratio

1.00

1.07

1.88

2.03

1.88

2.03

The formula for determining the peak frequency fO1 for 1M/outer track mode is shown below:

fo1 = 534/RF + 6.2 [kHz] RF: filter setting resistance [kΩ]

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