Features
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Current-controlled Output Current Source with 4 Input Channels
Two Selectable Outputs for Grounded Laser Diodes
Up to 350 mA Output Current per Channel
Total Output Current up to 500 mA
On-chip RF Oscillator
Oscillator Frequency Range from 200 MHz to 500 MHz
Individual Setting of RF Oscillator Current on Each Output by External Resistors
Maximum Oscillator Current Amplitude 100 mA
Single 5 V Power Supply
Common Enable/Disable Input
TTL/CMOS Compatible Control Signals
Small Pb-free QFN20 or SSO20 Package
Applications
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DVD-ROM with CD-RW Capability
DVD+RW with CD-RW Capability
DVD-RW with CD-RW Capability
Magneto-optical Drives and Others
Four Channel
Laser Driver
with RF
Oscillator and
Two Outputs
ATR0809
Summary
Description
ATR0809 is a laser diode driver for the operation of two different grounded laser
diodes for DVD-RW/+RW (650 nm) and CD-RW (780 nm). It includes four channels for
four different optical power levels. All channels (channel 1 = read channel, channel 2,
3, 4 = write channels) can be controlled by fast switches. The current pulses are
enabled when a low signal is applied to the NE pins. All channels are summed
together and switched to one of the two outputs IOUTA or IOUTB by the select input
SELA. Each write channel (channel 2, 3 and 4) can contribute up to 350 mA to the
total output current of up to 500 mA. The read channel can contribute up to 150 mA.
Total gains of 100 (read channel), 250 (channel 2 and 3) and 100 (channel 4) are pro-
vided between each reference current input and the selected output. Although the
reference inputs are current inputs, voltage control is also possible by using external
resistors.
An on-chip RF oscillator can be used to reduce laser mode hopping noise in
read mode. The oscillator current amplitude and frequency can be set independently
for the two selectable outputs with four different resistors
. Oscillation is enabled by a
high signal at the ENOSC pin. Complete shutdown of the output currents is achieved
by a low signal at the ENABLE input.
Rev. 4792BS–DVD–05/04
Figure 1.
Block Diagram
I4
NE4
I3
NE3
I2
NE2
Channel 4
Channel 3
IOUTA
IOUTB
Channel 2
IR
NER
ENABLE
Channel 1
Read channel
ENOSC
RF oscillator
RFA
RSA
RFB
RSB
SELA
2
ATR0809
4792BS–DVD–05/04
ATR0809
Pin Configuration SSO20
Figure 2.
Pinning SSO20
IR
I2
I3
I4
RFA
RFB
NER
NE2
NE3
NE4
1
2
3
4
5
6
7
8
9
10
20
19
18
17
16
15
14
13
12
11
VCC
ENABLE
IOUTA
GND
RSA
RSB
IOUTB
SELA
VCC
ENOSC
Pin Description
Pin
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
Symbol
IR
I2
I3
I4
RFA
RFB
NER
NE2
NE3
NE4
ENOSC
VCC
SELA
IOUTB
RSB
RSA
GND
IOUTA
ENABLE
VCC
Type
Analog
Analog
Analog
Analog
Analog
Analog
Digital
Digital
Digital
Digital
Digital
Supply
Digital
Analog
Analog
Analog
Supply
Analog
Digital
Supply
Function
Input current, bias voltage approximately GND
Input current, bias voltage approximately GND
Input current, bias voltage approximately GND
Input current, bias voltage approximately GND
External resistor to GND sets frequency of oscillator A
External resistor to GND sets frequency of oscillator B
Digital control of channel 1 (read, active low)
Digital control of channel 2 (active low)
Digital control of channel 3 (active low)
Digital control of channel 4 (active low)
Enables RF oscillator (active high)
5 V power supply
High: selects IOUTA, RSA, RFA
Low: selects IOUTB, RSB, RFB
Output current source B for laser diode
External resistor to GND sets swing of oscillator B
External resistor to GND sets swing of oscillator A
Ground
Output current source A for laser diode
Enables output current (active high)
5 V power supply
3
4792BS–DVD–05/04
Pin Configuration QFN20
Figure 3.
Pinning QFN20
I3
I2
IR
VCC
ENABLE
I4
RFA
RFB
NER
NE2
1
2
3
4
5
20 19 18 17 16
15
14
13
12
11
6 7 8 9 10
IOUTA
GND
RSA
RSB
IOUTB
Pin Description
Pin
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
Symbol
I4
RFA
RFB
NER
NE2
NE3
NE4
ENOSC
VCC
SELA
IOUTB
RSB
RSA
GND
IOUTA
ENABLE
VCC
IR
I2
I3
Type
Analog
Analog
Analog
Digital
Digital
Digital
Digital
Digital
Supply
Digital
Analog
Analog
Analog
Supply
Analog
Digital
Supply
Analog
Analog
Analog
Function
Input current, bias voltage approximately GND
External resistor to GND sets frequency of oscillator A
External resistor to GND sets frequency of oscillator B
Digital control of channel 1 (read, active low)
Digital control of channel 2 (active low)
Digital control of channel 3 (active low)
Digital control of channel 4 (active low)
Enables RF oscillator (active high)
5 V power supply
High: selects IOUTA, RSA, RFA
Low: selects IOUTB, RSB, RFB
Output current source B for laser diode
External resistor to GND sets swing of oscillator B
External resistor to GND sets swing of oscillator A
Ground
Output current source A for laser diode
Enables output current (active high)
5 V power supply
Input current, bias voltage approximately GND
Input current, bias voltage approximately GND
Input current, bias voltage approximately GND
4
ATR0809
4792BS–DVD–05/04
NE3
NE4
ENOSC
VCC
SELA
ATR0809
Absolute Maximum Ratings
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. This is a stress rating
only and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of this
specification is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.
Parameters
Supply voltage
Input voltage at any input
Power dissipation
Output voltage
Junction temperature
Storage temperature
Notes:
1. R
thJA
≤
115 K/W at T
amb
= 70°C
2. R
thJA
≤
115 K/W at T
amb
= 25°C
Symbol
V
CC
V
in
P
max
V
out
T
j
T
stg
Value
-0.5 to +6.0
-0.5 to V
CC
+0.5
0.7
(1)
to 1
(2)
-0.5 to V
CC
-1
150
-65 to +125
Unit
V
V
W
V
°C
°C
Thermal Resistance
Parameters
Junction case
Junction ambient
Note:
Symbol
R
thJC
R
thJA
Value
27
125
(1)
Unit
K/W
K/W
1. Measured with multi-layer test board (JEDEC standard)
Recommended Operating Conditions
Parameters
Supply voltage
Input current
External resistor to GND to set oscillator
frequency
External resistor to GND to set oscillator swing
Operating temperature range
Symbol
V
CC
I
IR
, I
I2
, I
I3
, I
I4
RFA, RFB
RSA, RSB
T
amb
Value
4.5 to 5.5
< 2.5
>3
>1
0 to +70
Unit
V
mA
kΩ
kΩ
°C
5
4792BS–DVD–05/04
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