Features • • • • • • • • • • • • Current-controlled Output Current Source with 4 Input Channels LVDS Compatible Inputs at Channels 2, 3 and 4 with On-chip 100Ω Termination Separate Read-channel Enable Two Selectable Outputs for Grounded Laser Diodes Output Current per Channel up to 350 mA Total Output Current up to 600 mA On-chip RF Oscillator Control of 2 Different Swings and Frequencies by use of 4 External Resistors Oscillator Frequency Range from 200 MHz to 500 MHz Maximum Oscillator Current Amplitude 100 mApp Single 5V Power Supply Small Pb-free QFN24, 4 mm × 4 mm Package Applications 4-Channel LVDS Laser Driver for Dual-layer Application • DVD+/-RW Dual Layer with CD-RW Capability • Recordable Optical Drives ATR0849 1. Description The ATR0849 is a laser diode driver designed to operate two different grounded laser diodes for DVD-RW/DVD+RW (650 nm) and CD-RW (780 nm). The device includes four channels for four different optical power levels. The write channels (channels 2 to 4) can be controlled by fast LVDS (Low Voltage Differential Signaling). Summary The read channel generates a continuous output current, whereas channels 2 to 4 are designed as write channels with very fast switching speed. All channels are summed together and routed to one of the two outputs, IOUTA or IOUTB, controlled by the select input, SELA. Each write channel (channel 2 to 4) can contribute up to 350 mA to the total output current of up to 600 mA. The read channel can contribute up to 150 mA. Total gains of 100 (read channel) and 250 (channels 2, 3 and 4), 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 available to reduce laser-mode hopping noise during read mode. The oscillator current amplitude 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 shutdown of the output currents is achieved by a low signal at the ENABLE input. In read mode, the reference currents (I2, I3, I4) should be switched off to reduce power consumption. In case of uncertain (balanced) enable signals, a built-in fail-safe circuit will reduce the laser diode output current to a safe value. Rev. 4851BS–DVD–06/05 Note: This is a summary document. A complete dorcument is available under NDA. For more information, please contact your local Atmel sales office. Figure 1-1. Block Diagram I4 E4 100 Channel 4 100 Channel 3 NE4 I3 E3 NE3 IOUTA I2 E2 NE2 IR NER ENABLE ENOSC IOUTB 100 Channel 2 Channel 1 Read channel RF oscillator RFA RFB RSA RSB 2 SELA ATR0849 4851BS–DVD–06/05 ATR0849 2. Pin Configuration Table 2-1. RFB 1 SELA VCC IR I2 I3 Pinning QFN24 I4 24 23 22 21 20 19 18 IOUTA 16 GND E2 4 15 RSA NE2 5 14 IOUTB E3 6 13 ENABLE 9 10 11 12 VCC 8 VCC 7 NE4 17 RSB 3 E4 2 NE3 RFA NER ENOSC Figure 2-1. Pin Description Pin Symbol Type 1 RFB Analog External resistor to GND sets frequency of oscillator B Function 2 RFA Analog External resistor to GND sets frequency of oscillator A 3 NER Digital Digital control of read channel (channel 1), active low 4 E2 Digital Digital control of channel 2 5 NE2 Digital Digital control of channel 2 6 E3 Digital Digital control of channel 3 7 NE3 Digital Digital control of channel 3 8 E4 Digital Digital control of channel 4 9 NE4 Digital Digital control of channel 4 10 ENOSC Digital Digital control of RF oscillator 11 VCC Supply +5V power supply 12 VCC Supply +5V power supply 13 ENABLE Digital Enables output current, active high 14 IOUTB Analog Output current source B for laser diode 15 RSA Analog External resistor to GND sets swing of oscillator A 16 GND Supply Ground, power supply 17 RSB Analog External resistor to GND sets swing of oscillator B 18 IOUTA Analog Output current source A for laser diode 19 SELA Digital High: selects IOUTA, RSA, RFA Low: selects IOUTB, RSB, RFB 20 VCC Supply +5V power supply 21 IR Analog Input current, bias voltage approximately GND 22 I2 Analog Input current, bias voltage approximately GND 23 I3 Analog Input current, bias voltage approximately GND 24 I4 Analog Input current, bias voltage approximately GND Paddle GND Supply Ground, negative power supply 3 4851BS–DVD–06/05 3. 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 Symbol Value Unit Supply voltage VCC –0.5 to +6.0 V Input voltage at any input Vin –0.5 to VCC + 0.5 V Voltage bettween LVDS inputs (E2/NE2, E3/NE3, E4/NE4) Vdmax 1.7 V Power dissipation Pmax 0.7(1 ) to 1(2) W Output voltage Vout –0.5 to VCC – 1 V Junction temperature Tj 150 °C Storage temperature Tstg –65 to +125 °C Symbol Value Unit RthJA 125 K/W Symbol Value Unit VCC 4.5 to 5.5 V IIR, II2, II3, II4 < 1.5 mA Vd 0.5 V External resistor to GND to set oscillator frequency RFA, RFB >3 kΩ External resistor to GND to set oscillator swing RSA, RSB > 100 Ω Tamb 0 to +70 °C Notes: 1. RthJA ≤ 115 K/W at Tamb = 70° C 2. RthJA ≤ 15 K/W at Tamb = 25° C 4. Thermal Resistance Parameters Junction ambient Note: Measured with multi-layer test board (JDEC standard) 5. Recommended Operating Range Parameters Supply voltage Input current Voltage bettween LVDS inputs (E2/NE2, E3/NE3, E4/NE4) Operating temperature range 4 ATR0849 4851BS–DVD–06/05 ATR0849 6. Ordering Information Extended Type Number Package Remarks ATR0849-PFQG Pb-free QFN24 (4 mm × 4 mm) Taped and reeled 7. Package Information 5 4851BS–DVD–06/05 Atmel Corporation 2325 Orchard Parkway San Jose, CA 95131, USA Tel: 1(408) 441-0311 Fax: 1(408) 487-2600 Regional Headquarters Europe Atmel Sarl Route des Arsenaux 41 Case Postale 80 CH-1705 Fribourg Switzerland Tel: (41) 26-426-5555 Fax: (41) 26-426-5500 Asia Room 1219 Chinachem Golden Plaza 77 Mody Road Tsimshatsui East Kowloon Hong Kong Tel: (852) 2721-9778 Fax: (852) 2722-1369 Japan 9F, Tonetsu Shinkawa Bldg. 1-24-8 Shinkawa Chuo-ku, Tokyo 104-0033 Japan Tel: (81) 3-3523-3551 Fax: (81) 3-3523-7581 Atmel Operations Memory 2325 Orchard Parkway San Jose, CA 95131, USA Tel: 1(408) 441-0311 Fax: 1(408) 436-4314 RF/Automotive Theresienstrasse 2 Postfach 3535 74025 Heilbronn, Germany Tel: (49) 71-31-67-0 Fax: (49) 71-31-67-2340 Microcontrollers 2325 Orchard Parkway San Jose, CA 95131, USA Tel: 1(408) 441-0311 Fax: 1(408) 436-4314 La Chantrerie BP 70602 44306 Nantes Cedex 3, France Tel: (33) 2-40-18-18-18 Fax: (33) 2-40-18-19-60 ASIC/ASSP/Smart Cards 1150 East Cheyenne Mtn. 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