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Features
• • • • • • • • • • • • •
Current-controlled Output Current Source with 3 Input Channels Two Selectable Outputs for Grounded Laser Diodes Output Current per Write Channel: 350 mA Total Output Current: 500 mA 500 Ω Channel Input Resistance On-chip RF Oscillator Control of Two Different Swings by Use of Two External Resistors Oscillator Frequency Range from 200 MHz to 500 MHz Oscillator Swing: 100 mA Single 5 V Power Supply Common Enable/Disable Input TTL/CMOS Control Signals Small Pb-free QFN16 (4 mm x 4 mm) or SSO16 Package
Applications
• • • •
DVD-ROM with CD-RW Capability DVD+RW with CD-RW Capability DVD-RW with CD-RW Capability Writable Optical Drives
Three Channel Laser Driver with RF Oscillator and Two Outputs ATR0807 (Summary)
Description
The ATR0807 is a laser diode driver for the operation of two different grounded laser diodes for DVD-RW/DVD+RW (650 nm) and CD-RW (780 nm). It includes three channels for three different optical power levels which are controlled by a separate IC. The read channel generates a continuous output level, whereas the channels 2 and 3 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 and switched to one of the two IOUTA or IOUTB outputs by the select input SELA. Each write channel (channel 2 and 3) can contribute up to 350 mA to the total output current, up to 500 mA. The read channel can contribute up to 150 mA. Total gains of 100 (read channel), 250 (channel 2 and 3) are 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. An on-chip RF oscillator is provided to reduce laser mode hopping noise during read mode. Swing can be set independently for the two selectable outputs with two different resistors. Oscillation is enabled by a high signal at the ENOSC pin. Complete output current and oscillator switch-off is achieved by a low signal at the ENABLE input.
Rev. 4723CS–DVD–07/03
1
Figure 1. Block Diagram
I3 NE3
Channel 3 IOUTA IOUTB Channel 2
I2 NE2
IR ENABLE
Read channel
ENOSC
RF oscillator
RF RSA RSB
SELA
2
ATR0807
4723CS–DVD–07/03
ATR0807
Pin Configuration SSO16
Figure 2. Pinning SSO16
IR I2 I3 RF NE2 NE3 ENABLE ENOSC 1 2 3 4 5 6 7 8 16 15 14 13 12 11 10 9 VCC1 IOUTA GND RSA RSB IOUTB SELA VCC2
Pin Description
Pin 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 Symbol IR I2 I3 RF NE2 NE3 ENABLE ENOSC VCC2 SELA IOUTB RSB RSA GND IOUTA VCC1 Type Analog Analog Analog Analog Digital Digital Digital Digital Supply Digital Analog Analog Analog Supply Analog Supply Function 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 Digital control of channel 2 (low active) Digital control of channel 3 (low active) Enables output current (high active) Enables RF oscillator (high active) +5 V power supply for IOUT High: selects IOUTA, RSA Low: selects IOUTB, RSB 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 +5 V power supply for IOUT and circuit
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4723CS–DVD–07/03
Pin Configuration QFN16
Figure 3. Pinning QFN16
I3 RF NE2 NE3
1 2 3 4
16 15 14 13 12 11 10 9 5 6 7 8 ENABLE ENOSC VCC2 SELA
I2 IR VCC1 IOUTA GND RSA RSB IOUTB
Pin Description
Pin 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 Paddle Symbol I3 RF NE2 NE3 ENABLE ENOSC VCC2 SELA IOUTB RSB RSA GND IOUTA VCC1 IR I2 GND Type Analog Analog Digital Digital Digital Digital Supply Digital Analog Analog Analog Supply Analog Supply Analog Analog Supply Function Input current, bias voltage approximately GND External resistor to GND sets frequency of oscillator Digital control of channel 2 (low active) Digital control of channel 3 (low active) Enables output current (high active) Enables RF oscillator (high active) +5 V power supply for IOUT High: selects IOUTA, RSA Low: selects IOUTB, RSB 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 +5 V power supply for circuit Input current, bias voltage approximately GND Input current, bias voltage approximately GND Ground
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ATR0807
4723CS–DVD–07/03
ATR0807
Absolute Maximum Ratings
Parameters Supply voltage Input voltage at any input Power dissipation Output voltage Junction temperature Storage temperature Notes: 1. RthJA £ 115 K/W at Tamb = 70°C 2. RthJA £ 115 K/W at Tamb = 25°C Symbol VCC Vin Pmax Vout Tj Tstg Value -0.5 to +6.0 -0.5 to VCC +0.5 0.7
(1)
Unit V V W V °C °C
to 1
(2)
-0.5 to VCC -1 150 -65 to +125
Thermal Resistance
Parameters Junction ambient Notes: Symbol RthJA Value 115.