Document
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 www.DataSheet4U.com • Small SSO16 Package
4-Channel Laser Driver with RF Oscillator T0820
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. Complete output current and oscillator switch-off is achieved by a `low' at the ENABLE input. Figure 1. Block Diagram
I4 NE4 Channel 4
I3 NE3 I2 NE2 IR ENABLE
Channel 3
Channel 2
IOUT
Read channel
ENOSC
RF oscillator
RF
RS
Rev. 4506E–DVD–09/02
1
Pin Configuration
Figure 2. Pinning SSO16
IR I2 RF
www.DataSheet4U.com
1 2 3 4
16 15 14 13
VCC1 VCC2 IOUT GND RS ENABLE ENOSC VCC2
I3 I4 NE2 NE3 NE4
T0820
5 6 7 8 12 11 10 9
Pin Description
Pin 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 Symbol IR I2 RF I3 I4 NE2 NE3 NE4 VCC2 ENOSC ENABLE RS GND IOUT VCC2 VCC1 Type analog analog analog analog analog digital digital digital supply digital digital analog supply analog supply supply Function Input current, bias voltage approximately GND Input current, bias voltage approximately GND External resistor to GND sets oscillator frequency Input current, bias voltage approximately GND Input current, bias voltage approximately GND Digital control of channel 2 (low active) Digital control of channel 3 (low active) Digital control of channel 4 (low active) +5 V power supply for IOUT Enables RF oscillator (high active) Enables output current (high active) External resistor to GND sets oscillator swing Ground Output current source for laser diode +5 V power supply for IOUT +5 V power supply for circuit
2
T0820
4506E–DVD–09/02
T0820
Absolute Maximum Ratings
Parameters Supply voltage Input voltage at IR, I2, I3, I4 Input voltage at NE2, NE3, NE4, ENOSC Output voltage Power dissipation Junction temperature Storage temperature range Notes: 1. RthJA £ 115 k/W, Tamb = 70°C www.DataSheet4U.com 2. RthJA £ 115 k/W, Tamb = 25°C Symbol VCC VIN1 VIN2 VOUT PMAX Tj Tstg Value -0.5 to +6.0 -0.5 to +0.8 -0.5 to VCC +0.5 -0.5 to VCC -1 0.7
(1)
Unit V V V V W _C _C
to 1
(2)
150 -65 to +125
Thermal Resistance
Parameters Junction ambient Note: Symbol RthJA Value 115
(1)
Unit K/W
1. Measured with multi-layer test board (JEDEC standard)
Operating Range
Parameters Supply voltage range Input current External resistor to GND to set oscillator frequency External resistor to GND to set oscillator swing Operating temperature range Symbol VCC IIR, II2, II3, II4 RF RS Tamb Value 4.5 to 5.5 <2 >3 > 100 0 to +70 Unit V mA kW W °C
3
4506E–DVD–09/02
Electrical Characteristics: General
VCC = 5 V, Tamb = 25°C, ENABLE = High, NE2 = NE3 = NE4 = High, ENOSC = Low, unless otherwise specified
No. 1 1.1 1.2 Parameters Power supply Supply current, power down Supply current, read mode, oscillator disabled ENABLE = Low, NE2 = NE3 = NE4 = Low IIR = II2 = II3 = II4 = 500 mA IIR = II2 = II3 = II4 = 500 mA, ENOSC = High, RS = 560 W, RF = 7.5 kW IIR = II2 = II3 = II4= 500 mA, NE2 = NE3 = NE4 = Low IIR = II2 = II3 = II4 = 0 mA 9, 15, 16 9, 15, 16 ICCPD2 ICCR1 0.3 mA A Test Condition Pin Symbol Min. Typ. Max. Unit Type*
95
mA
A
Supply current, read www.DataSheet4U.com mode, oscillator enabled
1.3
9, 15, 16
ICCR2
100
mA
A
1.4
Supply current, write mode Supply current, input off Digital inputs NE2/NE3/NE4 low voltage NE2/NE3/NE4 high voltage ENABLE low voltage ENABLE high voltage ENOSC low voltage ENOSC high voltage
9, 15, 16 9, 15, 16
ICCW ICCoff
230
mA
A
1.5 2 2.1 2.2 2.3 2.4 2.5 2.6 3 3.1 3.2 3.3 3.4 3.5 3.6
16
mA
A
6, 7, 8 6, 7, 8 11 11 10 10 NE = 0 V NE = 5 V ENABLE = 0 V ENABLE = 5 V ENOSC = 0 V ENOSC = 5 V
VNELO VNEHI VEN.