la6503 Sanyo Semiconductor Corporation, la6503 Datasheet - Page 7

• Manufacturer Part Number: la6503
• Description: Cd-rom Drive Spindle Motor Driver Sled Motor Driver Sled Motion/position Detector Ic
• Manufacturer: Sanyo Semiconductor Corporation

Notes on Gain Adjustment (Sled Motor Block)
• Gain setting
• Output offset voltage
The sled motor block gain is set using an external resistor as shown below.
For example, when the external resistor R is 22 k , the gain will be 0 dB when seen as an independent output amplifier
and 6 dB when seen as a BTL circuit (between outputs). Referenced to this 22-k
amplifier gain will be 22k/R (as a multiple) or 20 log(22k/R) dB. Similarly, the BTL gain will be 2 22k/R
(as a multiple) or 20 log(22k/R) dB + 3 dB. The level shifting circuits used in current models perform both current and
voltage conversion, and thus have a different input type from normal operational amplifiers. The current that flows in
the external resistor, that is, the potential difference, becomes the input to AMP1 and AMP2.
The output offset voltage is 1/2 V
this voltage.
(Input)
Resistor R
M
(typical). The V
O
LA6503
–
and V
O
+
outputs are converted to outputs that are centered on
resistor, the independent output
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