AD9660KR-REEL ,200 MHz Laser Diode Driver with Light Power ControlSpecifications subject to change without notice.–2– REV. 0AD96601EXPLANATION OF TEST LEVELSABSOLUTE ..
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ADS808Y/250G4 ,12-Bit, 70 MSPS ADC SE/Diff, Int/Ext Ref., Flexible Clocking, Selectable Fullscale Range & Powerdown 48-HTQFP -40 to 85ELECTRICAL CHARACTERISTICSAt T = full specified temperature range, differential input range = 1V to ..
ADS809Y/250 ,12-Bit, 80 MSPS ADC SE/Diff, Int/Ext Ref., Flexible Clocking, Selectable Fullscale Range and PwrdownFEATURES DESCRIPTION* DYNAMIC RANGE: The ADS809 is a high-dynamic range, 12-bit, 80MHz, pipelinedAn ..
ADS8201IRGER ,2.2V to 5.5V, Low-Power, 12-Bit, 100kSPS, 8-Channel DAS with PGA and SPI? 24-VQFN -40 to 85ELECTRICAL CHARACTERISTICS (continued)At T = –40°C to +85°C, 2.2V < VA = V < 5.5V, 2.2V < VD < 5.5V ..
ADS8201IRGET ,2.2V to 5.5V, Low-Power, 12-Bit, 100kSPS, 8-Channel DAS with PGA and SPI? 24-VQFN -40 to 85FEATURES • Multi-Chip Ready and Fully Enabled:234• Low-Power, Flexible Supply Range: – Global CONVS ..
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AD9660KR-AD9660KR-REEL
200 MHz Laser Diode Driver with Light Power Control
REV.0
FEATURES
1.5 ns Rise/2.0 ns Fall Times
Output Current:180 mA @ 3 V, 200 mA @ 2.5 V
Bias Current: 90mA @ 3 V
Modulation Current: 60mA @ 3 V
Offset Current: 30mA @ 3 V
Single +5V Power Supply
Switching Rate:200MHz
Onboard Light Power Control Loops
APPLICATIONS
Laser Printers and Copiers
Optical Disk Drives
FO Datacomm
GENERAL DESCRIPTIONThe AD9660 is a highly integrated driver for laser diode appli-
cations such as optical disk drives, printers, and copiers. The
AD9660 gets feedback from an external photo detector and in-
cludes 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 200MHz.
Output rise and fall times are typically 1.5 ns and 2.0 ns to
complement printer applications that use image enhancing tech-
niques 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.
200 MHz Laser Diode Driver
with Light Power ControlThe driver output provides up to 180 mA of current @ 3 V,
90 mA of BIAS current, 60 mA of modulation current, andmA 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 25MHz.
The AD9660 is offered in a 28-pin plastic SOIC for operation
over the commercial temperature range (0°C to +70°C).
AD9660
LASER
DIODE
WRITE
LEVEL
BIAS
LEVEL
BIAS
CAL
WRITE
PULSE
WRITE
CALIBRATE
NOTESPropagation delay measured from the 50% of the rising/falling transition of WRITE PULSE to 50% point of the rising/falling edge of the output modulation current.Rise time measured between the 10% and 90% points of the rising transition of the modulation current.Fall time measured between the 10% and 90% points of the falling transition of the modulation current.Aperture Delay is measured from the 50% point of the rising edge of WRITE PULSE to the time when the output modulation begins to recalibrate, WRITE CAL is
AD9660–SPECIFICATIONS
(+VS = +5 V, Temperature = +25°C unless otherwise noted. Sourced currents defined
as positive.)
ABSOLUTE MAXIMUM RATINGS1+VS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . +6 V
VREF Current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 mA
WRITE LEVEL, BIAS LEVEL . . . . . . . . . . . . . –0.5 V to +VS
TTL INPUTS . . . . . . . . . . . . . . . . . . . . . . . . . . –0.5 V to +VS
Output Current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 300 mA
Operating Temperature
AD9660KR . . . . . . . . . . . . . . . . . . . . . . . . . . 0°C to +70°C
Storage Temperature . . . . . . . . . . . . . . . . . . –65°C to +150°C
Maximum Junction Temperature2 . . . . . . . . . . . . . . . . +150°C
Lead Soldering Temp (10 sec) . . . . . . . . . . . . . . . . . . . +300°CAbsolute maximum ratings are limiting values, to be applied individually, and
beyond which the serviceability of the circuit may be impaired.Functional
operability under any of these conditions is not necessarily implied.Exposure of
absolute maximum rating conditions for extended periods of time may affect
device reliability.Typical thermal impedance is qJA = 45°C/W, qJC = 41°C/W.
EXPLANATION OF TEST LEVELS
Test Level100% Production Tested.
II.100% production tested at +25°C, and sample tested at
specified temperatures. AC testing doneon sample basis.
III.Sample Tested Only.
IV.Parameter is guaranteed by design and characterization
testing.Parameter is a typical value only.
VI.All devices are 100% production tested at +25°C,sample
tested at temperature extremes.
Equivalent Circuits
CAUTIONESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000V readily
accumulate on the human body and test equipment and can discharge without detection.
Although the AD9660 features proprietary ESD protection circuitry, permanent damage may
occur on devices subjected to high energy electrostatic discharges. Therefore, proper ESD
precautions are recommended to avoid performance degradation or loss of functionality.
PIN ASSIGNMENTS
WRITE CAL
WRITE PULSE
WRITE LEVEL
VREF
WRITE HOLD
GROUND
+VS
SENSE IN
GAIN
POWER MONITOR
+VS
GROUND
BIAS HOLD
BIAS LEVEL
GROUND
OFFSET SET
OFFSET PULSE
+VS
+VS
OUTPUT
OUTPUT
+VS
OUTPUT
GROUND
OUTPUT
AD9660KR
ORDERING GUIDE
AD9660
PIN DESCRIPTIONS
6.25mV
–193.8mV
–120V
ANTEL
ARS1
PHOTO DETECTORFigure 1.Driving ML64116R Laser @ 30 mW
ROFFSET – kW
OFFSET0255101520Figure 2.IOFFSET vs. ROFFSET
THEORY OF OPERATIONThe AD9660 combines a very fast output current switch with
onboard analog light power control loops to provide the user
with a complete laser diode driver solution. The block diagram
illustrates the key internal functions. The control loops of the
AD9660, the bias loop and the write loop, adjust the output
current level, IOUT, so that the photo diode feedback current,
IMONITOR, out of SENSE IN is proportional to the analog input
voltage at BIAS LEVEL or WRITE LEVEL. Since the monitor
current is proportional to the laser diode light power, the loops
effectively control laser power to a level proportional to the ana-
log inputs. The control loops should be periodically calibrated
independently (see Choosing CBIAS HOLD and CWRITE HOLD).
The offset current generator produces an open loop output cur-
rent, IOFFSET. Its level is controlled by an external set resistor or
a current out DAC (see Figure 2). While IOFFSET is not cali-
brated as the currents from the bias and write loops are, it can
be very versatile (see Offset Current below).
AD9660
RECALIBRATE THE BIAS LOOP
POWER-UP
OR LASER
NOT IN USE
TIMERECALIBRATE WRITE LOOP
LASER POWER
MODULATED
BETWEEN
BIAS AND WRITE LEVELS
DISABLE
BIAS CAL
WRITE CAL
WRITE PULSE
LASER
OUTPUT POWER
CALIBRATED WRITEFigure 4.Normal Operating Mode
The disable circuit turns off IOUT and returns the hold capacitor
voltages to their minimum levels (minimum output current)
when DISABLE = logic HIGH. It is used during initial power-
up of the AD9660 or during time periods when the laser is inac-
tive. When the AD9660 is re-enabled the control loops must be
recalibrated.
Normal operation of the AD9660 involves (in order, see figure):The AD9660 is enabled (DISABLE = logic LOW).The input voltages (BIAS LEVEL and WRITE LEVEL) are
driven to the appropriate levels to set the calibrated laser di-
ode output power levels.The bias loop is closed for calibration (BIAS CAL = logic
HIGH), and then opened (BIAS CAL = logic LOW).The write loop is closed for calibration (WRITE PULSE and
WRITE CAL = logic HIGH) and then opened.While both loops are open, the laser is pulsed between the
two calibrated levels by WRITE PULSE.The bias and write loops are periodically recalibrated as
needed.The AD9660 is disabled when the laser will not be pulsed for
an indefinite period of time.
Control Loop Transfer FunctionsThe relationship between IMONITOR and VBIAS LEVEL is MONITOR=VBIASLEVEL-VREF
1.85·(RGAIN+50W)
once the bias loop is calibrated. When the bias loop is open
(BIAS CAL = logic LOW), its output current, IBIAS, is propor-
tional to the held voltage at BIAS HOLD; the external hold ca-
pacitor on this pin determines the droop error in the output bias
current between calibrations.
The relationship between IMONITOR and VWRITE LEVEL isVWRITELEVEL-VREF
When the write loop is open (WRITE CAL logic LOW),
IMODULATION is proportional to the held voltage at WRITE HOLD.
The external hold capacitor (WRITE HOLD) determines the
droop error between calibrations. IMODULATION may be switched
on and off by WRITE PULSE when the write loop is open.
OPTICAL OUTPUT – mWFigure 5.Typical Laser Diode Current-to-Optical
Power Curve
The sections below discuss choosing the external components in
the feedback loops for a particular application.
Choosing RGAINThe gain resistor, RGAIN, allows the user to match the feedback
loop’s transfer function to the laser diode/photo diode
combination.
The user should define the maximum laser diode output power
for the intended application, PLD MAX, and the corresponding
photo diode monitor current, IMONITOR MAX. A typical laser di-
ode transfer function is illustrated in Figure 5. RGAIN should be
chosen as: GAIN=1.6V
1.85·I50W.
