BA1701 Ver la hoja de datos (PDF) - ROHM Semiconductor

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BA1701

VSC∗ system processor IC

ROHM Semiconductor 

Audio ICs

FAdjustment procedure

(1) With Rate = 2.5X (VR6 = GND), apply DC270mV to

pin 12, and adjust VR1 so that the frequency of the wave-

form on pin 11 is 300kHz.

(2) With Rate = 2.5X, apply DC2.462mV to pin 12, and

adjust VR2 so that the frequency of the waveform on pin

11 is 12kHz.

(3) Repeat adjustments (1) and (2).

(4) With Rate = 2.5X, adjust VR3 so that the period of

the waveform on pin 12 is 19ms.

(5) With Rate = 1X (VR6 = Vref), adjust VR4 so that the

frequency at pin 1 is 300Hz.

(6) With Rate = 2.5X, adjust VR5 so that the frequency

at pin 1 is 750Hz.

(7) With Rate = 1X, input VIN = 500mV and fIN = 2.5kHz,

and adjust VR7 and VR8 so that the output distortion is

minimized.

* If you are not using the motor drive control circuit, ad-

justments (5) and (6) are not necessary.

BA1701

FOperation notes

(1) Use accurate film capacitors for the VCO time

constant capacitor C14 (0.22µF), the RAMP time constant

capacitor C17 (1µF), and the BBD clock time constant ca-

pacitor (0.0047µF).

(2) If the AF output pin (pin 8) has a capacitive load, you

must take precautions to ensure that the BA1701 AF am-

plifier does not oscillate. We recommend that you insert

R19 (about 10kΩ) in the signal output line.

(3) To prevent oscillation, position the earth point of the

BBD clock time constant pin (pin 9) close to the GND pin

(pin 13) (see Fig. 6).

FElectrical characteristic curves

867

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