CXA2581 View Datasheet(PDF) - Sony Semiconductor
Part Name
Description
Manufacturer
CXA2581 Datasheet PDF : 22 Pages
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CXA2581N
• EQ
In
HPF
Amp
LPF
LPF
fc
Boost
EQ CNT
RFC 26 VFC 25 BST 24
VCC
VC
VC
The diagram to the left shows the EQ internal block
diagram.
The EQ consists of a combination of HPF and LPF.
The HPF and LPF transmittance is the Bessel function.
The boost gain can be adjusted by adjusting the HPF
gain.
Out
The boost frequency is adjusted by the RFC external
resistance value and the VFC control voltage value.
RFC resistance value: The cut-off frequency fo of each
filter is adjusted by the Pin 26
external resistance value.
The VFC voltage can be varied
using this fo as the reference.
VFC voltage: fo can be changed by the voltage applied
to Pin 25.
The boost gain can be adjusted by the BST pin control
voltage.
The control characteristics are shown in the graph below.
Boost Gain [dB]
8dB
The cut-off frequency control characteristics are
shown in the graph below.
fc [Hz]
1.5fo
fo
0dB
VC – 1.0
VC
VC + 1.0
Pin 24 (BST) voltage
Vcnt
[V]
0.5fo
VC – 1.0
VC
VC + 1.0
Pin 25 (VFC) voltage
Vcnt
[V]
• APC (Automatic Power Control)
When the laser diode is driven by a constant current, the optical power output has extremely large negative
temperature characteristics. Therefore, the current must be controlled to maintain the monitor photo diode
output at a constant level. This control is performed by the APC function.
VCC
PD 2
56k
10k
1 LD
1k
55k
10k
10k
56k
1.25V
– 10 –
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