CXA2534Q
Description of Operation
1. H-Bridge Driver
a) Gain Setting
The input resistances of the Sled, Focus and Track channels are 11 kΩ (typical); the input resistance of
the Spindle channel is 7.5 kΩ (typical). The gain can be adjusted by connecting a external resistor, R at
the input pin of the channel.
Channel
Sled channel
Unit
dB
55 kΩ
Focus channel
Track channel
GV = 20 log
GV = 20 log
R - External Resistor
11 kΩ + R
110 kΩ
Spindle channel
dB
7.5 kΩ + R
b) Mute
The Spindle channel operates normally when the SP MUTE (pin 13) is open or at LOW (below 0.8 V).
The output will be muted when the SP MUTE pin is at HIGH (above 2 V). This is a high impedance
mute as the spindle output voltage will be not pulled to LOW.
The Focus and Track channels share the same mute pin (pin 8). The channels are muted when the FT
MUTE pin (pin 8) is open or at LOW level (below 0.8 V). When the Focus and Track channels are
muted, the quiescent current at the VCC2 pin is also reduced by almost half. This is because the bias
are removed when the mute is on.
c) Thermal Shutdown
The H-bridge Driver has an internal thermal shutdown circuit. All the channels outputs will be muted
when the chip temperature exceeds 170 °C (typical) and restored when the chip temperature falls to 140
°C (typical).
d) VREF pin
When the VREF pin (pin 4) is below 1 V (typical), the H-bridge driver will be at standby mode and the
quiescent current is zero (typical).
e) Dead Band
Dead band = 2 × input Resistance (attached external resistor + internal resistor) × 0.5 µA
The dead band is depended on input resistance. Thus, the dead band varies with the gain settings.
The dead band is 7.5 mV for Spindle channel and 11 mV for Sled, Focus and Track channels.
—18—
SONY [ SONY CORPORATION ]
