Rev. 4506FDVD09/04
Features
Current-controlled Output Current Source with 4 Input Channels
Low-power Consumption
Output Current up to 150 mA, Read Channel and Channel 2
Output Current up to 200 mA, Channel 3 and Channel 4
Total Output Current to 300 mA
Rise Time 1.0 ns, Fall Time 1.1 ns
On-chip RF Oscillator
Control Frequency and Swings by Use of 2 External Resistors
Oscillator Frequency Range from 200 MHz to 600 MHz
Oscillator Swing to 100 mA
Single 5 V Power Supply
Common Enable/Disable Input
TTL/CMOS Control Signals
Small SSO16 Package
Application
DVD-RAM
DVD-RW
DVD+RW
CD-RW
Writable Optical Drives
Description
The T0820 is a laser diode driver for the operation of a grounded laser diode for
writable optical drives. It includes four channels for four different optical power levels
which are controlled by a separate IC. The read channel generates a continuous
output level whereas channels 2 to 4 are provided as write channels with very fast
switching speeds. Write current pulses are enabled when a "low" signal is applied to
the NE pins. All channels are summed together at the IOUT pin. Read channel and
channel 2 can contribute up to 150 mA and channels 3 and 4 up to 200 mA to the total
output current of up to 300 mA. A total gain of 100 is provided between each reference
current input and the selected output. Although the reference inputs are current inputs
voltage control is possible by using external resistors. Frequency and swing can be set
by two external resistors. Oscillation is enabled by a "high" at the ENOSC pin. Com-
plete output current and oscillator switch-off is achieved by a `low' at the ENABLE
input.
Figure 1. Block Diagram
Channel 3
Channel 2
I3
NE3
I2
NE2
Read channel
RF oscillator
IR
ENOSC
ENABLE
IOUT
I4
RF
RS
Channel 4
NE4
4-channel Laser
Driver with RF
Oscillator
T0820
2
T0820
4506FDVD09/04
Pin Configuration
Figure 2. Pinning SSO16
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
RF
I3
I4
NE2
NE3
NE4
IR
I2
IOUT
GND
RS
ENABLE
ENOSC
VCC2
VCC1
VCC2
T0820
Pin Description
Pin
Symbol
Type
Function
1
IR
Analog
Input current, bias voltage approximately GND
2
I2
Analog
Input current, bias voltage approximately GND
3
RF
Analog
External resistor to GND sets oscillator frequency
4
I3
Analog
Input current, bias voltage approximately GND
5
I4
Analog
Input current, bias voltage approximately GND
6
NE2
Digital
Digital control of channel 2 (low active)
7
NE3
Digital
Digital control of channel 3 (low active)
8
NE4
Digital
Digital control of channel 4 (low active)
9
VCC2
Supply
+5 V power supply for IOUT
10
ENOSC
Digital
Enables RF oscillator (high active)
11
ENABLE
Digital
Enables output current (high active)
12
RS
Analog
External resistor to GND sets oscillator swing
13
GND
Supply
Ground
14
IOUT
Analog
Output current source for laser diode
15
VCC2
Supply
+5 V power supply for IOUT
16
VCC1
Supply
+5 V power supply for circuit
3
T0820
4506FDVD09/04
Absolute Maximum Ratings
Parameters
Symbol
Value
Unit
Supply voltage
V
CC
-0.5 to +6.0
V
Input voltage at IR, I2, I3, I4
V
IN1
-0.5 to +0.8
V
Input voltage at NE2, NE3, NE4, ENOSC
V
IN2
-0.5 to V
CC
+0.5
V
Output voltage
V
OUT
-0.5 to V
CC
-1
V
Power dissipation
P
MAX
0.7
(1)
to 1
(2)
W
Junction temperature
T
j
150
_
C
Storage temperature range
T
stg
-65 to +125
_
C
Notes:
1. R
thJA
115 k/W, T
amb
= 70C
2. R
thJA
115 k/W, T
amb
= 25C
Thermal Resistance
Parameters
Symbol
Value
Unit
Junction ambient
R
thJA
115
(1)
K/W
Note:
1. Measured with multi-layer test board (JEDEC standard)
Operating Range
Parameters
Symbol
Value
Unit
Supply voltage range
VCC
4.5 to 5.5
V
Input current
I
IR
, I
I2
, I
I3
, I
I4
<2
mA
External resistor to GND to set oscillator
frequency
RF
>3
k
External resistor to GND to set oscillator swing
RS
>100
Operating temperature range
T
amb
0 to +70
C
4
T0820
4506FDVD09/04
Electrical Characteristics: General
V
CC
= 5 V, T
amb
= 25C, ENABLE = High, NE2 = NE3 = NE4 = High, ENOSC = Low, unless otherwise specified
No.
Parameters
Test Condition
Pin
Symbol
Min.
Typ.
Max.
Unit
Type*
1
Power supply
1.1
Supply current, power
down
ENABLE = Low, NE2
= NE3 = NE4 = Low
9, 15,
16
ICC
PD2
0.3
mA
A
1.2
Supply current,
read mode,
oscillator disabled
I
IR
= I
I2
= I
I3
= I
I4
=
500
A
9, 15,
16
ICC
R1
95
mA
A
1.3
Supply current,
read mode,
oscillator enabled
I
IR
= I
I2
= I
I3
= I
I4
=
500
A,
ENOSC = High,
RS = 560
,
RF = 7.5 k
9, 15,
16
ICC
R2
100
mA
A
1.4
Supply current,
write mode
I
IR
= I
I2
= I
I3
= I
I4
=
500
A, NE2 = NE3 =
NE4 = Low
9, 15,
16
ICC
W
230
mA
A
1.5
Supply current,
input off
I
IR
= I
I2
= I
I3
= I
I4
= 0
A
9, 15,
16
ICC
off
16
mA
A
2
Digital inputs
2.1
NE2/NE3/NE4 low
voltage
6, 7, 8
VNE
LO
1.3
V
A
2.2
NE2/NE3/NE4 high
voltage
6, 7, 8
VNE
HI
2.0
V
A
2.3
ENABLE low voltage
11
VEN
LO
0.5
V
A
2.4
ENABLE high voltage
11
VEN
HI
3.0
V
A
2.5
ENOSC low voltage
10
VEO
LO
0.5
V
A
2.6
ENOSC high voltage
10
VEO
HI
3.0
V
A
3
Current at digital inputs
3.1
NE2/NE3/NE4 low
current
NE = 0 V
6, 7, 8
INE
LO
-300
A
A
3.2
NE2/NE3/NE4 high
current
NE = 5 V
6, 7, 8
INE
HI
800
A
A
3.3
ENABLE low current
ENABLE = 0 V
11
IEN
LO
-150
A
A
3.4
ENABLE high current
ENABLE = 5 V
11
IEN
HI
100
A
A
3.5
ENOSC low current
ENOSC = 0 V
10
IEO
LO
-100
A
A
3.6
ENOSC high current
ENOSC = 5 V
10
IEO
HI
800
A
A
* Type means: A: 100% tested B: 100% correlation tested C: Characterized on samples D: Design parameter
5
T0820
4506FDVD09/04
Electrical Characteristics: Laser Amplifier
V
CC
= 5 V, T
amb
= 25C, ENABLE = High, unless otherwise specified
No.
Parameters
Test Conditions
Pin
Symbol
Min.
Typ.
Max.
Unit
Type*
4
Laser Amplifier
4.1
Best fit current gain
Any channel
(1)
14
GAIN
90
105
130
mA/mA
A
4.2
Best fit current offset
Any channel
(1)
14
IOS
-8
+4
mA
A
4.3
Output current linearity
Any channel
(1)
14
ILIN
-3
+3
%
A
4.4
Input current range
Input is sinking
1, 2,
4, 5
IDAC
0
3
mA
C
4.5
Output current read
channel
Output is sourcing
14
I
OUTR
150
mA
A
4.6
Output current channel 2
Output is sourcing
14
I
OUT2
150
mA
A
4.7
Output current channel 3
Output is sourcing
14
I
OUT3
200
mA
A
4.8
Output current channel 4
Output is sourcing
14
I
OUT4
200
mA
A
4.9
Output current read
channel + channel 2
Output is sourcing
14
I
OUTR,2
150
mA
A
4.10
Output current channel 3
+ channel 4
Output is sourcing
14
I
OUT3,4
200
mA
A
4.11
Total output current
Output is sourcing
14
I
OUT
300
mA
A
4.12
IOUT series resistor
I
OUT
= 250 mA total
R
OUT
to V
CC
-Rail
14
R
OUT
8
C
4.13
I
IN
input impedance
R
IN
is to GND
1, 2,
4, 5
R
IN
150
200
250
A
4.14
NE threshold
Temperature
stabilized
6, 7, 8
VTH
1.68
V
B
4.15
Output off current 1
ENABLE = Low
IOFF
1
1
mA
A
4.16
Output off current 2
NE2=NE3=NE4=High
I
IR
=0 A,
I
I2
=I
I3
=I
I4
= 500 A
14
IOFF
2
1
mA
A
4.17
Output off current 3
NE2=NE3=NE4=Low,
I
IR
=I
I2
=I
I3
=I
I4
= 0 A
14
IOFF
3
5
mA
A
4.18
I
OUT
supply sensitivity,
read mode
I
OUT
= 40 mA,
V
CC
= 5 V
10%,
read only
14
VSE
R
-4
-1
%/V
A
4.19
I
OUT
supply sensitivity,
write mode
I
OUT
= 80 mA, 40 mA
read + 40 mA write,
V
CC
=5V
10%
14
VSE
W
-4
0.2
%/V
A
4.20
I
OUT
current output noise
I
OUT
= 40 mA,
ENOSC = Low
14
INO
O
3
nA/
rt-Hz
C
4.21
I
OUT
temperature
sensitivity, read mode
I
OUT
= 40 mA, read
only
14
TSE
R
-500
ppm/
C
C
4.22
I
OUT
temperature
sensitivity, write mode
I
OUT
= 80 mA, 40 mA
read + 40 mA Write
14
TSE
W
-600
ppm/
C
C
*) Type means: A =100% tested, B = 100% correlation tested, C = Characterized on samples, D = Design parameter
Note:
1. Linearity of the amplifier is calculated using a best fit method at three operating points of
I
OUT
at 20 mA, 40 mA, and 60 mA. I
OUT
= (I
IN
GAIN) + I
OS
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