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SY88216L
3.3V, 2.5Gbps Burst Mode Laser Driver
General Description
The SY88216L is a single supply 3.3V burst mode laser driver for A-PON, B-PON, EPON, GE-PON, and G-PON applications with data rates from 155Mbps up to 2.5Gbps. The driver can deliver modulation current up to 85mA, and provides a high compliance voltage that makes it suitable for high-current operation with the laser DC-coupled to it. All support documentation can be found on Micrel's web site at: www.micrel.com.
Features
* * * * * * * * * 2.4V minimum laser compliance voltage Operation up to 2.5Gbps Fast burst mode enable/disable delay Modulation current up to 85mA Bias current up to 70mA Infinite bias current hold time between bursts Safety features Power monitoring Available in 24-pin (4mm x 4mm) MLF(R) package
Applications
* Multi-rate burst mode applications: A-PON, B-PON, G-PON, E-PON, GE-PON
Markets
* Fiber-to-the-Premises (FTTP): Fiber-to-the-Home (FTTH), Fiber-to-the-Business (FTTB) * FTTC (Fiber-to-the-Curb) ___________________________________________________________________________________________________________
Typical Application
MLF and MicroLeadFrame are registered trademarks of Amkor Technology. Micrel Inc. * 2180 Fortune Drive * San Jose, CA 95131 * USA * tel +1 (408) 944-0800 * fax + 1 (408) 474-1000 * http://www.micrel.com
April 2008
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Micrel, Inc.
SY88216L
Ordering Information(1)
Part Number SY88216LMG SY88216LMGTR
Notes: 1. Contact factory for die availability. Dice are guaranteed at TA = +25C, DC Electrical only. 2. Tape and Reel.
(2)
Package Type MLF-24 MLF-24
Operating Range Industrial Industrial
Package Marking 216L with Pb-Free bar-line indicator 216L with Pb-Free bar-line indicator
Lead Finish NiPdAu Pb-Free NiPdAu Pb-Free
Pin Configuration
24-Pin MLF(R) (MLF-24)
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SY88216L
Pin Description
Pin Number 2 3 5 6 7 Pin Name DIN+ DINBEN+ BEN/EN Pin Function Non-inverting input data. Internally terminated with 50 to a reference voltage. Inverting input data. Internally terminated with 50 to a reference voltage. Non-inverting burst enable. Accepts any input, single-ended or differential: TTL/CMOS, LVPECL, CML, LVDS, HSTL, and SSTL. BEN requires an external termination. See Figure 2. Inverting burst enable. Accepts any input, single-ended or differential: TTL/CMOS, LVPECL, CML, LVDS, HSTL, and SSTL. BEN requires an external termination. See Figure 2. Active low TTL/CMOS. Internally pulled-up. Pull-down with a 22k or lower resistance or apply a low level signal (<0.8 V) to enable bias and modulation. Keep floating or apply a high level (>2 V) to disable. Internal oscillator setting option. Install a 0 resistor from this pin to VCC or leave it open to set the frequency. Refer to the frequency table. Indicates APC failure when low. Active low TTL/CMOS. Power Monitor. Provides a current which is proportional to the sum of bias current and half of modulation current. Install a resistor between this pin and GND to convert that current to a voltage. Inverting laser bias current output. Pull-up to VCC with a resistor. Non-inverting laser bias current output, sources current when BEN is high. Connect to the cathode of the laser through a resistor. Non-inverted modulation current output. Provides modulation current when input data is positive. Inverted modulation current output. Provides modulation current when input data is negative. Input from the laser monitoring photodiode. Connect to the anode of the photodiode for APC operation. Install a resistor between this pin and GND to set the maximum bias current for the closed loop operation. The APC loop controls the bias current up to the level of BIASMAX. When the bias current reaches the maximum value set through this pin, the driver continues to sink a current equal to this maximum. For open loop operations, this pin sets the bias current. Modulation current setting and control. The modulation current is set by installing an external resistor from this pin-to-ground or using a current source. Bias current setting and control. The bias current is set by installing an external resistor from this pin to ground or using a current source. Connect a 50K resistor-to-GND for open loop operation. Ground. Ground and exposed pad must be connected to the plane of the most negative potential. Supply Voltage. Bypass with a 0.1F//0.01F low ESR capacitor as close to VCC pin as possible.
9 10 12
OSC /APCFAULT PWRMON
13 14 16 17 20 22
BIASBIAS+ MOD+ MODMD BIASMAX
23 24
MODSET APCSET
8, 11,19 1, 4, 15, 18, 21
GND VCC
Truth Table
DIN+ L H X
Notes: 1. 2. IMOD = 0 when MOD+ = H. Assuming that the laser is tied to MOD+.
Oscillator Frequency
/EN L L H MOD+ H L H
(1)
DINH L X
MODL H L
Laser Output(2) L H L
OSC Open VCC
Frequency (MHz) 25 50
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Micrel, Inc.
SY88216L
Absolute Maximum Ratings(1)
Supply Voltage (VCC).................................... -0.5V to +4.0V CML Input Voltage (VIN) ....................VCC-1.2V to VCC+0.5V TTL Control Input Voltage (VI)..................... 0V to VCC+0.3V Lead Temperature (soldering, 20sec.)..................... +260C Storage Temperature (Ts) .........................-65C to +150C
Operating Ratings(2)
Supply Voltage (VCC).................................... +3.0V to +3.6V Ambient Temperature (TA) .......................... -40C to +85C Package Thermal Resistance(3) MLF(R) (JA) Still-air........................................................75C/W (JB) ...................................................................30C/W
DC Electrical Characteristics
TA = -40C to +85C and VCC = +3.0V to +3.6V. Unless otherwise noted, typical values are VCC = +3.3V, TA = 25C, IMOD = 25mA, IBIAS = 20mA.
Symbol ICC VMOD_MIN Parameter Power Supply Current Minimum Voltage Required at the Driver Output, MOD+ and MOD-, for Proper Operation Minimum Voltage Required at the Driver Output, BIAS+ and BIAS-, for Proper Operation Bias-ON Current Bias-OFF Current Input Resistance at DIN+ and DINDifferential Input Voltage Swing /EN Input Low /EN Input High /APCFAULT Output Low /APCFAULT Output Leakage Burst Mode Enable Signal High Voltage Low Voltage Input Voltage Swing Differential Input Voltage Swing Maximum Voltage at PWRMON Pin Current Range at MD Pin IOL = 2mA VOH = VCC Single Ended BEN+, BENBEN+, BENBEN+, BENBEN+, BEN-0.3 100 200 1.25 50 1500 0.8 VCC + 0.3 2 0.5 100 Voltage at Bias pin 0.8V Current at BIAS pin when /EN is high or BEN is low Single ended 42.5 100 50 Condition Modulation and Bias currents excluded 0.6 Min Typ 55 Max 95(4) Units mA V
VBIAS_MIN
0.8
V
IBIAS IBIAS_OFF RIN VDIFF-IN (DIN) VIL (/EN) VIH (/EN) VOL IOH BEN+, BENVIH (BEN) VIL (BEN) VIN (BEN) VDIFF-IN (BEN) VPWRMON IMD
Notes:
1
70 150 57.5 2400 0.8
mA A mVPP V V V A V V V mV mVPP V A
1. Permanent device damage may occur if absolute maximum ratings are exceeded. This is a stress rating only and functional operation is not implied at conditions other than those detailed in the operational sections of this data sheet. Exposure to absolute maximum ratings conditions for extended periods may affect device reliability. 2. The data sheet limits are not guaranteed if the device is operated beyond the operating ratings. 3. Package Thermal Resistance assumes exposed pad is soldered (or equivalent) to the devices most negative potential on the PCB. JB uses a 4-layer and JA in still air unless otherwise stated. 4. ICC = 95mA for worst-case conditions with IMOD = 85mA, IBIAS = 70mA, TA = +85C, VCC = 3.6.
April 2008
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Micrel, Inc.
SY88216L
AC Electrical Characteristics
TA = -40C to +85C and VCC = +3.0V to +3.6V. Unless otherwise noted, typical values are VCC = +3.3V, TA = 25C, IMOD = 25mA, IBIAS = 20mA.
Symbol Parameter Data Rate IMOD Modulation Current(5) Condition NRZ AC-coupled DC-coupled, Voltage at MOD Pin 0.6V Current at MOD+ when /EN is High or BEN is High Current at MOD- when /EN is High or BEN is Low 20% to 80%, IMOD = 60mA 20% to 80%, IMOD = 60mA 155Mbps Jitter Total Jitter(7) 622Mbps 1.25Gbps 2.5Gbps Power up with /En Low and BEN High tINIT 60 60 Min 0.155 10 10 Typ Max 2.5 85 70(6) 150 150 85 85 30 30 30 30 12 10 2.5 2.5 2 155Mbps Burst ON-Time 622Mbps 1.25Gbps 2.5Gbps 155Mbps Burst OFF-Time 622Mbps 1.25Gbps 2.5Gbps
Notes: 5. Load = 15. 6. Assuming VCC = 3.0V, Laser bandgap voltage = 1V, laser package inductance = 1nH, laser equivalent series resistor = 5, and damping resistor = 10. 7. Total jitter is measured using 2 - 1 PRBS pattern. 8. Measured with a laser equivalent resistive load. 9. Burst Enable Delay is measured as the time between the instant when the BEN+ signal going from low to high reaches 50% of its amplitude and the instant at which the modulation current or the bias current (whichever takes longer) reaches 90% of its final value. 10. Burst Disable Delay is measured as the time between the instant when the BEN+ signal going from high to low reaches 50% of its amplitude and the instant at which the modulation current or the bias current (whichever takes longer) goes below 10% of its final value.
7
Units Gbps mA mA A A ps ps
IMOD_OFF
Modulation OFF Current
tr tf
Output Current Rise Time Output Current Fall Time
psPP
s s ns ns ns s ns ns ns s ns ns ns
APC Loop Initialization Time
/EN Changes from High to Low with Power ON and BEN High BEN Changes from Low to High with Power ON and /EN Low
Burst Enable Delay(8, 9) Burst Disable Delay
(8, 10)
1.9 720 576 576 1.9 720 576 576
April 2008
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SY88216L
Functional Diagram
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SY88216L APC Loop Function At start up, with the driver enabled and burst mode enabled, the laser turns ON within a few microseconds and its back facet monitoring photodiode starts to generate a photocurrent proportional to the optical power. The photocurrent is fed back to the MD pin on the driver where it's converted to a voltage. The conversion voltage is compared to APCSET on the driver. At equilibrium, the feedback voltage equals the APCSET voltage and the laser optical power reaches its nominal value. If the laser power deviates from its nominal value, the APC loop brings it back to its nominal setting. After everything is settled to its nominal value and the BEN changes from high to low to disable the burst mode, the instantaneous bias current value is latched until BEN switches from low to high again. Then the bias and modulation output stages turn ON and the bias stays equal to the stored value until the feedback from the monitoring photodiode reaches the APCSET value and the APC closed loop starts to regulate the laser power. APC Loop Failure The APCFAULT is asserted Low if the bias current reaches BIASMAX or if the APC loop counter reaches its minimum or its maximum counts. Interfacing the Driver with the Laser Diode As shown on the "Typical Application" drawing, MOD+ pin is connected to the laser cathode through a 10 resistor and MOD- pin is connected to VCC with a 15 resistor equivalent to 10 (damping resistor) in series with the laser (equivalent resistor of 5). The laser can be driven differentially by connecting MOD- to the anode of the laser through 15 (15 pull-up removed) and isolating the anode of the laser from VCC with an inductor. To meet the stringent laser turn-ON time, per BPON/GPON/EPON spec, the bias (BIAS+ pin) must be connected to the cathode of the laser through a resistor not an inductor as in continuous mode. BIAS- pin is pulled-up to VCC.
Detailed Functional Description
The SY88216L burst mode laser driver is comprised from a fast modulator, a fast bias circuit, and a digital APC loop that allows for fast laser turn-ON time. The modulator is comparable to a fast continuous mode modulator that turns ON in the nanosecond range. The bias circuit has a differential pair at the output to allow for fast turn-ON time. Both modulator and bias differential pairs can be enabled for burst operation by applying a high level signal at BEN+ pin and a low level signal at BEN- pin. The driver features a power monitoring function. BIAS and Modulation Setting Bias and modulation currents are set by installing resistors from APCSET (pin24)-to-ground and from MODSET (pin23)-to-ground respectively or by applying a negative current at those pins. IBIAS variation versus RAPCSET resistor, IBIAS variation versus RBIASMAX resistor, and IMOD variation versus RMODSET resistor are shown on Page 8. BIASMAX A resistor between the BIASMAX pin and ground sets the maximum bias the driver can sink. At normal operation, the bias current tracks the laser optical power through the laser monitoring photodiode and the APC loop to compensate for any power deviation from the nominal value set at the start of operation using APCSET. If any failure occurs (laser or photodiode degradation, open feedback circuit etc.) the APC loop keeps increasing the bias current in an effort to compensate for the low power indication, the bias current will then stop increasing when it reaches BIASMAX value and continue to operate at that maximum value and APCFAULT asserted. BIASMAX also controls the bias current when the circuit is operating in the open loop mode.
April 2008
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Micrel, Inc.
SY88216L
Typical Characteristics
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Micrel, Inc.
SY88216L
Functional Characteristics
April 2008
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Micrel, Inc.
SY88216L
Input and Output Stages
Figure 1a. Simplified Input Stage
Figure 1b. Simplified BEN Input Stage
Figure 1c. Simplified Output Stage
Interfacing DIN and BEN Inputs to Different Logic Drivers
Figure 2a. Driving DIN and BEN with PECL Outputs
Figure 2b. Driving DIN and BEN with CML Outputs
Figure 2c. Driving BEN with LVTTL/LCMOS Outputs
Figure 2d. Driving BEN with LVDS Outputs
April 2008
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M9999-040809-B hbwhelp@micrel.com or (408) 955-1690
Micrel, Inc.
SY88216L
Package Information
24-Pin (3mm x 3mm) MicroLeadFrame(R) (MLF-24)
MICREL, INC. 2180 FORTUNE DRIVE SAN JOSE, CA 95131 USA
TEL +1 (408) 944-0800 FAX +1 (408) 474-1000 WEB http://www.micrel.com
The information furnished by Micrel in this data sheet is believed to be accurate and reliable. However, no responsibility is assumed by Micrel for its use. Micrel reserves the right to change circuitry and specifications at any time without notification to the customer. Micrel Products are not designed or authorized for use as components in life support appliances, devices or systems where malfunction of a product can reasonably be expected to result in personal injury. Life support devices or systems are devices or systems that (a) are intended for surgical implant into the body or (b) support or sustain life, and whose failure to perform can be reasonably expected to result in a significant injury to the user. A Purchaser's use or sale of Micrel Products for use in life support appliances, devices or systems is a Purchaser's own risk and Purchaser agrees to fully indemnify Micrel for any damages resulting from such use or sale. (c) 2007 Micrel, Incorporated.
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