AD9660KR

a FEATURES 1.5 ns Rise/2.0 ns Fall Times Output Current: 180 mA @ 3 V, 200 mA @ 2.5 V Bias Current: 90 mA @ 3 V Modulation Current: 60 mA @ 3 V Offset Current: 30 mA @ 3 V Single +5 V Power Supply Switching Rate: 200 MHz Onboard Light Power Control Loops APPLICATIONS Laser Printers and Copiers Optical Disk Drives FO Datacomm 200 MHz Laser Diode Driver with Light Power Control AD9660 FUNCTIONAL BLOCK DIAGRAM WRITE PULSE WRITE CALIBRATE WRITE LEVEL T/H V:1 OUTPUT DRIVER OUTPUT LASER DIODE TRANSIMPEDANCE AMPLIFIER SENSE INPUT PHOTO DETECTOR DIODE BIAS LEVEL BIAS CAL BIAS T/H V:1 OUTPUT DRIVER AD9660 GENERAL DESCRIPTION The AD9660 is a highly integrated driver for laser diode applications such as optical disk drives, printers, and copiers. The AD9660 gets feedback from an external photo detector and includes two analog feedback loops to allow users to set “bias” and “write” (for optical disk drives) power levels of the laser, and switch between the two power levels at up to 200 MHz. Output rise and fall times are typically 1.5 ns and 2.0 ns to complement printer applications that use image enhancing techniques such as pulse width modulation to achieve gray scale, and allow disk drive applications to improve density and take advantage of pulsed write formats. Control signals are TTL/ CMOS compatible. The driver output provides up to 180 mA of current @ 3 V, 90 mA of BIAS current, 60 mA of modulation current, and 30 mA of offset current. The onboard disable circuit turns off the output drivers and returns the light power control loops to a safe state. The AD9660 can also be used in closed loop applications in which the output power level follows an analog WRITE LEVEL voltage input. By optimizing the external hold capacitor, and the photo detector, the write loop can achieve bandwidths as high as 25 MHz. The AD9660 is offered in a 28-pin plastic SOIC for operation over the commercial temperature range (0°C to +70°C). REV. 0 Information furnished by Analog Devices is believed to be accurate and reliable. However, no responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other rights of third parties which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of Analog Devices. © Analog Devices, Inc., 1995 One Technology Way, P.O. Box 9106, Norwood. MA 02062-9106, U.S.A. Tel: 617/329-4700 Fax: 617/326-8703 AD9660–SPECIFICATIONS as positive.) Parameter ANALOG INPUTS (WRITE LEVEL, BIAS LEVEL) Input Voltage Range Input Bias Current Analog Bandwidth OUTPUTS Maximum Output Current, IOUT IOUT Bias Current, IBIAS Modulation Current, IMODULATION Offset Current, IOFFSET Output Compliance Range Idle Current SWITCHING PERFORMANCE Maximum Pulse Rate Output Propagation Delay (tPD), Rising1 Output Propagation Delay (tPD), Falling1 Output Current Rise Time2 Output Current Fall Time3 WRITE CAL Aperture Delay4 Disable Time5 HOLD NODES (WRITE HOLD, BIAS HOLD) Input Bias Current Input Voltage Range Minimum External Hold Cap TTL INPUTS6 Logic “1” Voltage Logic “1” Voltage Logic “0” Voltage Logic “0” Voltage Logic “1” Current Logic “0” Current BANDGAP REFERENCE Output Voltage VREF Temperature Coefficient Output Current SENSE IN Current Gain Voltage Input Resistance POWER SUPPLY (DISABLE = HIGH) +VS Voltage +VS Current Power Dissipation OFFSET CURRENT OFFSET SET Voltage Test Level Temp IV I V I I I I I I I Full +25°C Full +25°C +25°C +25°C +25°C +25°C +25°C +25°C (+VS = +5 V, Temperature = +25°C unless otherwise noted. Sourced currents defined AD9660KR Typ Max Min Units Conditions VREF –50 25 200 180 90 60 30 0 3 VREF + 1.6 +50 V µA MHz mA mA mA mA mA V mA External Hold Cap = 20 pF VOUT = 2.5 V VOUT = 3.0 V VOUT = 3.0 V VOUT = 3.0 V VOUT = 3.0 V WRITE PULSE = LOW, DISABLE = HIGH 3 dB Reduction in IOUT 3.0 13 IV IV IV IV IV V V +25°C Full Full Full Full +25°C +25°C 200 1.6 1.6 1.1 1.4 250 1.5 2.0 13 5 3.0 2.5 1.7 2.8 MHz ns ns ns ns ns ns I IV V I IV I IV I I I V V V I V I I I I +25°C Full Full +25°C Full +25°C Full +25°C +25°C +25°C +25°C +25°C +25°C +25°C +25°C +25°C +25°C +25°C –200 VREF 20 2.0 2.0 –10 –1.5 1.55 –0.5 1.85 4.0