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FEATURES Data Rates from 9.952 Gbps to 10.709 Gbps Typical Rise/Fall Time 25 ps/23 ps Bias Current Range 3 mA to 80 mA Modulation Current Range 5 mA to 80 mA Monitor Photodiode Current 50 A to 1200 A Closed-Loop Control of Both Average Optical Power and Extinction Ratio Laser Fail and Laser Degrade Alarms Automatic Laser Shutdown, ALS Dual MPD Functionality for Wavelength Control CML Data Inputs 50 Internal Data Terminations 3.3 V Single-Supply Operation Driver Supplied in Dice Format APPLICATIONS SONET OC-192, SDH STM-64 Supports 10.667 Gbps and 10.709 Gbps FEC Rates 10 Gb Ethernet IEEE802.3ae
10.709 Gbps Laser Diode Driver Chipset ADN2843
GENERAL DESCRIPTION
The ADN2943 chipset consists of two components, the ADN2845 and the ADN2844. The ADN2845 is a 10.709 Gbps laser diode driver. The ADN2845 eliminates the need to ac couple since it can deliver 80 mA of modulation while dc coupled to the laser diode. It is intended to be copackaged with the laser to minimize bond lengths, which improves performance of the optical transmitter. For transmission line applications, contact HSN Application Group at fiberoptic.ic@analog.com. The ADN2844 offers a unique control loop algorithm and provides dual loop control of both average power and extinction ratio. Programmable alarms are provided for laser fail (end of life) and laser degrade (impending fail). Both the ADN2844 and the ADN2845 are available as bare die. The ADN2844 is also available in 5 mm 5 mm 32-lead LFCSP.
FUNCTIONAL BLOCK DIAGRAM
IMPDMON2 DEGRADE IMPDMON
IMMON
IBMON
VCC MPD
VCC
FAIL
VCC
VCC
VCC LD
ADN2844
ADN2843
ADN2845
IMPD IMODP GND IMPD2 CONTROL IMOD_CTRL D_IMOD * GND ERSET * GND ERCAP GND IDTONE GND *ADN2850 OR ADN2860 OPTICAL SUPERVISOR PAVCAP ASET ALS GND IBIAS_CTRL IBIAS GND DATAN IMODN DATAP
MODE ALS PSET
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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 that may result from its use. No license is granted by implication or otherwise under any patent or patent rights of Analog Devices. Trademarks and registered trademarks are the property of their respective companies.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A. Tel: 781/329-4700 www.analog.com Fax: 781/326-8703 (c) 2003 Analog Devices, Inc. All rights reserved.
V to 3.6 values as C.) ADN2843-SPECIFICATIONS (V = 3.0specifiedV,atAll25specifications T
CC
MIN
to TMAX, unless otherwise noted. Typical
Parameter LASER BIAS (BIAS) Output Current IBIAS Compliance Voltage IBIAS during ALS ALS Shutdown Response Time MODULATION CURRENT (IMODP, IMODN) Output Current IMOD Compliance Voltage IMOD during ALS Rise Time Fall Time Random Jitter Total Jitter POWER SET INPUT (PSET) External Capacitance Voltage EXTINCTION RATIO SET INPUT (ERSET) Allowable Resistance Range Voltage ALARM SET (ASET) Allowable Resistance Range Voltage Hysteresis CONTROL LOOP Time Constant DATA INPUTS (DATAP, DATAN) V p-p (Single-Ended Peak-to-Peak) Input Impedance (Single-Ended) LOGIC INPUTS (ALS, MODE) VIH
Min 3 1.2
Typ
Max 80 VCC - 1.0 10 10 80 VCC 10
Unit mA V A s mA V A ps ps fs rms ps p-p pF V k V k V % s
Conditions
See Note 1 See Note 2
5 1.2 25 23 170 7.41
See Note 3 See Note 4 See Note 5
1.15 1.5 1.15 1.2 1.15 5 0.22 300
80 1.35 25 1.35 13.2 1.35
800
mV
50
2.4 V
VIL
ALARM OUTPUTS (Internal 30 k to V CC) VOH 2.4
0.8
V
V
VOL
IDTONE fIN Input Current Range Voltage on IDTONE MONITOR PD (MPD, MPD2) Current Input Voltage IBMON, IMMON, IMPDMON, IMPDMON2 IBMON, IMMON Division Ratio IMPDMON, IMPDMON2 IMPDMON to IMPDMON2 Matching Compliance Voltage SUPPLY VCC ICC (ADN2844) ICC (ADN2845) 10 50 VCC - 2 50
0.4
1000 4000
V
kHz A V A V A/A A/A % V V mA mA
1200 1.65 100 1
0 3.0 3.3 75
2 VCC - 1.5 3.6 36
Measured at 1200 A
See Note 6 See Note 6
NOTES 1 In ALS mode current is sourced to the laser from the I BIAS pin, which reverse biases the laser. 2 The ADN2845 high speed specifications are measured into a 5 load. 3 RMS jitter measured with a 0000 0000 1111 1111 repeating pattern at 10.7 Gbps rate. 4 Peak-to-peak total jitter measured with a 2 13 - 1 PRBS with 80 CIDs pattern at 10.7 Gbps rate. 5 Max capacitance refers to capacitance of photodiode and other parasitic capacitance. 6 IBIAS = 0, IMOD = 0 (when ALS is asserted). See Power Dissipation section on page 7 for calculation of complete power dissipation. Specifications subject to change without notice.
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ADN2843
ABSOLUTE MAXIMUM RATINGS*
(TA = 25C, unless otherwise noted.)
ORDERING GUIDE
VCC to GND . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.2 V Digital Inputs (ALS, MODE) . . . . . . . . -0.5 V to VCC + 0.3 V IMODN, IMODP . . . . . . . . . . . . . . . . . . . . . . . . . VCC + 1.2 V MOD_CONTROL to GND . . . . . . . . . . . . . . -0.5 V to 4.2 V IBIAS_CONTROL to GND . . . . . . . . . . . . . . -0.5 V to 4.2 V D_MOD to GND . . . . . . . . . . . . . . . . . . . . . . -0.5 V to 4.2 V DATAP to GND . . . . . . . . . . . . . . . . . . . . . . . -0.5 V to 4.2 V DATAN to GND . . . . . . . . . . . . . . . . . . . . . . -0.5 V to 4.2 V Operating Temperature Range Industrial . . . . . . . . . . . . . . . . . . . . . . . . . . . -40C to +85C Storage Temperature Range . . . . . . . . . . . . . -65C to +150C Junction Temperature (TJ Max) . . . . . . . . . . . . . . . . . . 150C
*Stresses above those listed under Absolute Maximum Ratings may cause permanent damage to the device. This is a stress rating only; functional operation of the device at these or any other conditions above those listed in the operational sections of this specification is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.
Model ADN2843CHIPSET
Temperature Range
Package Option
-40C to +85C ADN2844 Control Loop: 32-Lead LFCSP ADN2845 Data Switch: Dice
ADN2843CHIPSET-B -40C to +85C ADN2844 Control Loop: Dice ADN2845 Data Switch: Dice EVAL-ADN2843 Evaluation Board
ADN2844 METALLIZATION PHOTOGRAPH
DEGRADE IDTONE IBMON IMMON
GND
GND GND
VCC
ALS
FAIL
GND
IBIAS_CTRL GND
GND
GND
MODE IMOD_CTRL PAVCAP D_IMOD ERCAP GND VCC GND GND
2390 m
IMPDMON
PSET
IMPD
3000 m
CAUTION ESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000 V readily accumulate on the human body and test equipment and can discharge without detection. Although the ADN2843 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.
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IMPDMON2
ERSET
IMPD2
ASET
GND
ADN2843
ADN2845 METALLIZATION PHOTOGRAPH
VCC VCC VCC GND
DATAN
VCC (IMODN TERM)
GND NC 1340 m ( 20 m) NC IMODP
IBIAS GND NC DATAP
ALS IMOD_CTRL IBIAS_CTRL GND 1140 m ( 20 m)
PIN CONFIGURATIONS
IBIAS_CTRL IMOD_CTRL D_IMOD
GND
GND
GND
GND
32
31
30
29
VCC
28
27
26
25
1
ASET 1 ERSET 2 PSET 3 GND 4 IMPD 5 IMPDMON 6 IMPDMON2 7 IMPD2 8
9 10 11 12 13 14 15 16
24 23 22
IDTONE IBMON IMMON ALS FAIL DEGRADE GND GND
GND
VCC
VCC
VCC
DATAN GND
VCC (IMODN TERM)
ADN2845
PAD PITCH: 200 m MAXIMUM DIE SIZE: 1.16mm 1.36mm DIE THICKNESS: 0.25mm SINGLE PAD SIZE: 92 m 92 m DOUBLE PAD SIZE: 151 m 92 m
NC IMODP IBIAS NC
ADN2844
BOND PAD SIZE: >115 m BOND PAD PITCH: >104 m DIE SIZE: 3000 m 2390 m
21 20 19 18 17
NC
GND DATAP
IMOD_CTRL
-4-
IBIAS_CTRL
GND
VCC
GND
GND
ERCAP
PAVCAP
MODE
GND
GND
ALS
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ADN2843
ADN2844 PIN FUNCTION DESCRIPTIONS
Pin No. 1 2 3 4 5 6 7 8 9 10 11 12 13 14, 15, 17 18, 31, 32 16 19 20 21 22 23 24 25 26 27 28 29 30
Mnemonic ASET ERSET PSET GND IMPD IMPDMON IMPDMON2 IMPD2 GND VCC ERCAP PAVCAP MODE GND GND GND DEGRADE FAIL ALS IMMON IBMON IDTONE GND VCC IBIAS_CTRL GND IMOD_CTRL D_IMOD
Function Alarm Current Threshold Set (Should be Terminated with a 1.2 k Resistor when Not Used) Extinction Ratio Current Set Average Optical Power Set Negative Supply Monitor Photodiode Current Input (Tie to GND when Not in Use) Mirrored Current from IMPD (Tie to VCC when Not in Use) Mirrored Current from IMPD2 (For Optional Use with Two MPDs, Tie to VCC when Not in Use) Optional Second MPD Current Input (Tie to GND when Not in Use) Negative Supply Positive Supply Extinction Ratio Loop Capacitor Average Power Loop Capacitor Control Loop Operating Mode Logic Input (Should Not Be Left Floating) Negative Supply Negative Supply Negative Supply DEGRADE Alarm Output, Open Collector, Active High FAIL Alarm Output, Open Collector, Active High Automatic Laser Shutdown Logic Input (Should Not Be Left Floating) Modulation Current Mirror Output, Current Source from VCC Bias Current Mirror Output, Current Source from VCC ID Tone Input Current (Tie to VCC when Not in Use) Negative Supply Positive Supply Control Output Current Sink Negative Supply Control Output Current Sink Control Output Current Sink
ADN2845 PIN FUNCTION DESCRIPTIONS
Pin No. 1 2 3, 13 4 5 6 7 8 9 10 11 12 14 15 16-18
Mnemonic DATAN GND NC GND DATAP ALS IMOD_CTRL IBIAS_CTRL GND NC IBIAS IMODP VCC GND VCC
Function AC-Coupled CML Data, Negative Differential Terminal Negative Supply No Connect, Leave Floating Negative Supply AC-Coupled CML Data, Positive Differential Terminal Automatic Laser Shutdown Logic Input Modulation Current Control Input (Control Circuit Sinks IMOD/10 from Pin to GND) BIAS Current Control Input (Control Circuit Sinks IBIAS/10 from Pin to GND) Negative Supply No Connect, Leave Floating BIAS Current Modulation Current VCC Connection for IMODN Termination Resistor Negative Supply Positive Supply
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-5-
ADN2843
GENERAL
Laser diodes have current-in to light-out transfer functions as shown in Figure 1. Two key characteristics of this transfer function are the threshold current, ITH, and slope in the linear region beyond the threshold current, referred to as the slope efficiency, LI.
ER = P1 P0 P1
OPTICAL POWER
force the PSET and ERSET pins to 1.23 V above GND. For initial setup, RPSET and RERSET may be calculated using the following formulas: The PSET resistor is given by the following formulas: 1.23 V RPSET = (W ) I AV where IAV is average MPD current.
PAV = P1 + P0 2 P
The value of the ERSET resistor is a function of the operation mode of the ADN2843 as follows:
LI = I P I
PAV
For Mode A: R ERSET = R PSET For Mode B: ER + 1 ER - 1
P0 ITH CURRENT
R ERSET =
R PSET ER + 1 2 ER - 1
Figure 1. Laser Transfer Function
CONTROL
A monitor photodiode, MPD, is required to control the LD. The MPD current is fed into the ADN2843 to control the power and extinction ratio, continuously adjusting the bias current and modulation current in response to the laser's changing threshold current and light-to-current slope efficiency. The ADN2843 uses automatic power control, APC, to maintain a constant average power over time and temperature. The ADN2843 uses closed-loop extinction ratio control to allow optimum setting of the extinction ratio for every device. Thus, SONET/SDH interface standards can be met over device variation, temperature, and laser aging. Closed-loop modulation control eliminates the need to either overmodulate the LD or include external components for temperature compensation, thus reducing research and development time and second sourcing issues. The ADN2843 dual-loop control has two modes of operation. Each mode is given by the configuration of the MODE and D_IMOD pins as shown below. Operation Mode A B MODE Pin Setting HIGH LOW D_IMOD Pin Connected to IBIAS IBIAS_CTRL
Note that IERSET and IPSET will change from laser diode to laser diode, therefore RERSET and RPSET need to be adjusted for each laser diode. When tuning the laser diode, RPSET should be adjusted first with RERSET at 25 k . Once the average power is set, RERSET is adjusted to set the desired extinction ratio, and RPSET is again adjusted to re-establish the desired average power. Once the values RPSET and RERSET have been adjusted to set the desired average power and extinction ratio, the control loops maintain these values of average power and extinction ratio over environmental conditions and time.
PAVCAP AND ERCAP
The control loop constants are set by the PAVCAP and ERCAP capacitors. The required value for the PAVCAP and ERCAP capacitors is 22 nF. The PAVCAP and ERCAP capacitors are connected between the respective pins and GND. The capacitors should be low leakage multilayer ceramic capacitors with an insulation resistance >100 G or an RC >1000 s, whichever is lowest.
ALARMS
Configuring the ADN2843 in Mode A or Mode B (see Figures 3 and 4) enables users to achieve accurate control of the extinction ratio. Mode B is suitable for applications where an IBIAS pin is not available to the TOSA, or where there is no space on the TOSA for an IBIAS inductor. Experimental data and simulation for typical lasers has shown ER to be 0.3 dB to 0.5 dB better in Mode A, at a 5 dB extinction ratio. Care should be taken to ensure that the extra capacitance on the IBIAS pin due to the D_IMOD connection does not degrade the eye quality. When physical constraints do not allow a low capacitance interconnect between D_IMOD and IBIAS, the ADN2843 should be configured in Mode B (see Figure 4). Average power and extinction ratio for both modes are set using the PSET and ERSET pins, respectively. Potentiometers are connected between these pins and ground. The potentiometer RPSET is used to set the average power. The potentiometer RERSET is used to set the extinction ratio. The internal control loops -6-
The ADN2843 is designed to allow interface compliance to ITU-T-G958 (11/94), Section 10.3.1.1.2 (Transmitter Fail), and Section 10.3.1.1.3 (transmitter degrade). The ADN2843 has two alarms, DEGRADE and FAIL. These alarms are raised when IBIAS exceeds the respective DEGRADE and FAIL thresholds. These alarms are active high. A resistor between ground and the ASET pin is used to set the current at which these alarms are raised. The current through the ASET resistor is a ratio of 1:100 to the FAIL alarm threshold. The DEGRADE alarm will be raised at 90% of the FAIL threshold. Example:
I FAIL = 50 mA so I DEGRADE = 45 mA I ASET = R ASET I FAIL 50 mA = = 500 A 100 100 1.23 V 1.23 V = = = 2.46 kW 500 A I ASET
The laser degrade alarm, DEGRADE, is provided to give a warning of imminent laser failure if the laser diode degrades further or if environmental conditions continue to stress the LD, such as increasing temperature.
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ADN2843
The laser fail alarm, FAIL, is activated when the transmitter can no longer be guaranteed to be SONET/SDH compliant. This occurs when one of the following conditions arise: The ASET threshold is reached. The ALS pin is set high. This shuts off the modulation and bias currents to the LD, resulting in the MPD current dropping to zero. This gives closed-loop feedback to the system that ALS has been enabled. DEGRADE is raised only when the bias current exceeds 90% of the alarm threshold.
ALARM INTERFACE
tor photodiode cathode should be connected directly to the PSET node, and IMPDMON and IMPDMON2 should be tied to VCC. MPD currents as high as 3 mA can be used in this configuration. Another way to increase the MPD current range without sacrificing the monitoring function is to use IMPD and IMPD2 in parallel. This effectively doubles the current range but raises the lower MPD current specification from 50 A to 100 A. If this configuration is used, the IMPDMON and IMPDMON2 pins should be tied together and terminated with a single resistor. The mirror ratio of 1 is maintained in this configuration.
DUAL MPD DWDM FUNCTION
The alarm voltages are open collector outputs. An internal pull-up resistor of 30k that is used to pull the logic high value to VCC. However, this can be overdriven with an external resistor, allowing alarm interfacing to non-VCC levels. The FAIL output may not be connected directly to the ALS pin to shut down the bias and modulation currents. It can however be latched using a flip-flop, and the output of the flip-flop can then be used to activate ALS. Non-VCC alarm output levels must be below the VCC used for the ADN2843.
DATA INPUTS
The MPD function mirrors the current in MPD to the PSET pin and to the IMPDMON pin with a ratio of 1. A second monitor photodiode can be connected to the IMPD2 pin. Its current is mirrored to IMPDMON2 and also to the PSET pin, where it is summed with the current mirrored from IMPD. The two MPD monitor currents can be used as inputs to a DWDM wavelength control function when used in combination with various optical filtering techniques. If the IMPD monitor function is not required, the monitor photodiode can be directly connected to the PSET pin, and the IMPD pin must be tied to GND. If the IMPD2 pin is not being used, it should be tied to GND.
IDTONE
Figure 2 shows a simplified schematic of the ADN2845 data inputs. The data inputs are terminated via the equivalent of a 100 internal resistor between DATAN and DATAP. This provides 50 termination for single-ended signals. The actual signal on the switching devices is attenuated by a factor of 2 internally. There is a high impedance circuit to set the commonmode voltage, which is designed to change over temperature. It is recommended that ac coupling be used to eliminate the need for matching between the common-mode voltages.
ADN2845
The IDTONE pin is supplied for fiber identification/supervisory channels or for control purposes. This pin modulates the optical one level by adding a current to IMOD over a possible range of 2% of minimum IMOD to 10% of maximum IMOD. The IDTONE current is set by an external current sink connected to the IDTONE pin. There is a gain of 2 between the IDTONE pin and the IMOD current. To ratio the IDTONE current to IMOD, the input current can be derived from the IMMON output current. If the IDTONE function is not being used, this pin must be tied to VCC to properly disable it. Note that using IDTONE during transmission may cause optical eye degradation.
DATAN
25
25 2k 25 DATAP 25 INTERNAL REFERENCE
AUTOMATIC LASER SHUTDOWN (ALS)
Figure 2. Simplified Schematic of Data Inputs
MONITOR CURRENTS
The ADN2843 ALS allows compliance to ITU-T-G958 (11/94), Section 9.7. When ALS is asserted, both bias and modulation currents are turned off. In ALS mode, current is sourced to the laser from the IBIAS pin, which reverse biases the laser and ensures that it is turned off. Correct operation of ALS can be confirmed by the FAIL alarm being raised when ALS is asserted. Note this is the only time that DEGRADE will be low while FAIL is high. Note that for correct ALS operation, the ALS pin on the ADN2845 and ADN2844 should be connected and terminated with a 10 kW resistor. The ADN2843 ALS should be driven with correct logic levels (see Specifications section). ALS should never be left floating.
POWER DISSIPATION
IBMON, IMMON mirror the bias, modulation current at a ratio of 1:100 for increased monitoring functionality. IMPDMON and IMPDMON2 mirror the current in IMPD and IMPD2, respectively, with a ratio of 1. All monitors source current from VCC. If the MPD monitoring function is not required, then the IMPD pin should be tied to ground and the monitor photodiode cathode should be connected directly to the PSET pin. When the MPD monitor functions are not used, IMPDMON and IMPDMON2 should be tied to VCC.
MPD CURRENT
The power dissipation of the ADN2845 can be calculated using the following expressions: I CC = 75 mA + 1.75 I MOD (mA) + 0.3 I BIAS (mA) P = VCC I CC ( A) + VIMOD I MOD ( A) / 2 + VIBIAS I BIAS ( A) where VIMOD is the average voltage on the IMOD pin, and VIBIAS is the average voltage on the IBIAS pin. -7-
The maximum average MPD current is specified in the specifications section. This maximum current specified is limited by the MPD monitoring circuitry. If the monitoring function is not required, then IMPD and IMPD2 should be grounded, the moniREV. 0
ADN2843
VCC VCC VCC 10nF VCC 18 10nF VCC 100 F TANTALUM
10nF
15 GND VCC VCC 1 DATAN IMODNTERM 14
VCC VCC 10nF MPD
GND NC GND 10nF
5
ADN2845
IBIAS_CTRL IMOD_CTRL
NC
IMODP IBIAS NC 10
9 GND
DATAP
ALS 6
VCC 10nF
32 25
IBIAS_CTRL
IMOD_CTRL
D_IMOD
GND
GND
GND
VCC
GND
VCC IDTONE 24 IBMON IMMON
1 ASET
ERSET PSET * * GND IMPD IMPDMON 1k ** VCC IMPDMON2 PAVCAP
8 IMPD2
ADN2844
ALS FAIL DEGRADE GND GND 17 MODE GND GND GND 10k
** ** 1k
1k
9
ERCAP
GND
VCC
16
10nF 22nF 22nF VCC VCC NOTES *FOR DIGITAL PROGRAMMING, THE ADN2850 OR ADN2860 OPTICAL SUPERVISOR CAN BE USED. **OPTIONAL MONITORING OF CURRENTS.
Figure 3. ADN2843 Application Circuit (Mode A)
* Best high frequency board layout techniques including power and ground planes should be used. * To minimize inductance, keep the connections between the ADN2845 and the laser diode as short as possible. Inductances <0.3 nH are recommended for best performance. Critical bonds are IMODP and VCC (Pin 14). Ribbon bonding can be used to reduce bond inductance. Minimize bond lengths for ADN2845 pads to achieve low inductance. * Place bypass capacitor on laser anode as close to laser as possible. * Bypass capacitors should be placed as close as possible to VCC pads. * 50 controlled impedance interconnects should be used on the DATA inputs. * Parasitic capacitance on IBIAS_CTRL and IMOD_CTRL interconnects should be less than 100 pF. If decoupling caps are used on IBIAS_CTRL and IMOD_CTRL, they should be tied to VCC rather than GND. * An inductor should be used in the bias current path. A Microwave Components coil 30-1847-GCCAS-01 (48 mil be used. 24 mil) should
* The recommended substrate connection is to GND. However, the performance is not affected by connecting the substrate to VCC.
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ADN2843
VCC VCC VCC 10nF VCC 18 10nF
1 DATAN
VCC 100 F TANTALUM 10nF
15 GND
VCC VCC IMODNTERM 14 NC
VCC VCC 10nF MPD
GND NC GND 10nF
ADN2845
IBIAS_CTRL IMOD_CTRL
IMODP IBIAS GND 10
9 GND
5 DATAP
ALS 6
VCC 10nF
32 25
IBIAS_CTRL
IMOD_CTRL
LBWSET
D_IMOD
GND
GND
GND
VCC
VCC IDTONE 24 IBMON IMMON
1
ASET ERSET PSET
*
* GND IMPD IMPDMON 1k ** IMPDMON2 VCC
ADN2844
ALS FAIL DEGRADE GND 10k ** 1k
**
1k
PAVCAP
ERCAP
8
IMPD2
GND 17
MODE
GND
GND
GND
9
16
10nF 22nF 22nF VCC
VCC
NOTES *FOR DIGITAL PROGRAMMING, THE ADN2850 OR ADN2860 OPTICAL SUPERVISOR CAN BE USED. **OPTIONAL MONITORING OF CURRENTS.
Figure 4. ADN2843 Application Circuit (Mode B)
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GND
VCC
ADN2843
PARALLEL PLATE DECOUPLING CAPACITOR GROUND PLANE PARALLEL PLATE DECOUPLING CAPACITORS
18
VCC VCC VCC
15
AGND VCC IMODNTERM
1
DATAN
14
CERAMIC WITH GOLD SURFACE THAT CONTACTS THE LASER'S ANODE
MPD
AGND
BACK FACET LIGHT
LASER LIGHT
ADN2845
AGND
IMODP
LASER
IBIAS
5
DATAP ALS IMOD_CTRL IBIAS_CTRL AGND
10
50
TRANSMISSION LINE
6
9
GROUND PLANE IBIAS OUTPUT INDUCTOR
NOTES * FOR OPTIMUM PERFORMANCE, RIBBON BONDS ARE RECOMMENDED ON PADS 1, 5, 12, AND 14. WIRES ARE 3 MIL OR 5 MIL RIBBONS <400 m * LONG. ALL OTHER PINS CAN BE ROUND WIRE <1mm. * LASER'S ANODE IS CONNECTED TO VCC THROUGH GOLD LAYER ON TOP OF CERAMIC STANDOFF. STANDOFF MINIMIZES LENGTH OF PAD * 12 AND PAD 14 RIBBONS. * PARALLEL PLATE DECOUPLING CAPACITORS SHOULD BE >100pF AND BE OF MICROWAVE AVX TYPE, PART NO. GB0159391KA6N (390pF). * THE RECOMMENDED SUBSTRATE CONNECTION IS TO GND. HOWEVER, PERFORMANCE IS NOT AFFECTED BY CONNECTING THE * SUBSTRATE TO VCC. * AN INDUCTOR SHOULD BE USED IN THE BIAS CURRENT PATH. A MICROWAVE COMPONENTS COIL 30-1847-GCCAS-01 (48 MIL 24 MIL) SHOULD BE USED. * THE EXTERNAL POWER SUPPLY IS CONNECTED AT THE PARALLEL PLATE DECOUPLING CAPACITOR.
Figure 5. Recommended Layout
Figure 6. 10 Gbps Optical Diagram Provided Courtesy of NEL. PAV = 0 dBm, ER = 5 dB, PRBS 31 Pattern.
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ADN2843
DIE PAD COORDINATES
(With Origin in the Center of the Die)
ADN2844 Pad Number 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 Pad Name ASET ERSET PSET GND IMPD IMPDMON IMPDMON2 IMPD2 GND VCC ERCAP PAVCAP MODE GND GND GND GND GND DEGRADE FAIL ALS IMMON IBMON IDTONE GND VCC IBIAS_CNTRL GND IMOD_CTRL D_IMOD GND GND X ( m) 1014.00 769.00 486.00 186.00 -132.00 -479.00 -811.00 -1056.00 -1339.00 -1339.00 -1339.00 -1339.00 -1339.00 -1339.00 -1339.00 -1339.00 -1051.00 -761.00 -476.00 -207.00 102.00 387.00 653.00 904.00 1359.00 1359.00 1359.00 1359.00 1359.00 1359.00 1359.00 1359.00 Y ( m) -1019.00 -1019.00 -1019.00 -1019.00 -1019.00 -1019.00 -1019.00 -1019.00 -877.00 -672.00 -429.00 -204.00 91.00 335.00 580.00 824.00 1019.00 1019.00 1019.00 1019.00 1019.00 1019.00 1019.00 1019.00 995.00 781.00 523.00 317.00 -29.00 -294.00 -562.00 -807.00 Pad Number 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18
*Denotes
ADN2845 Pad Name DATAN GND* NC GND* DATAP ALS IMOD_CTRL IBIAS_CTRL GND* NC* IBIAS IMODP* NC* VCC (IMODN)* GND* VCC* VCC* VCC*
double bond pad.
X ( m) -500.00 -500.00 -500.00 -500.00 -500.00 -300.00 -100.00 100.00 300.00 500.00 500.00 500.00 500.00 500.00 300.00 100.00 -100.00 -300.00
Y ( m) 400.00 222.00 0.00 -222.00 -400.00 -600.00 -600.00 -600.00 -600.00 -400.00 -200.00 -30.00 178.00 378.00 600.00 600.00 600.00 600.00
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ADN2843
OUTLINE DIMENSIONS 32-Lead Lead Frame Chip Scale Package [LFCSP] 5 mm 5 mm (CP-32)
Dimensions shown in millimeters
5.00 BSC SQ 0.60 MAX 0.60 MAX
25 24 32 1
PIN 1 INDICATOR
PIN 1 INDICATOR
TOP VIEW
4.75 BSC SQ
0.50 BSC
BOTTOM VIEW
3.25 3.10 SQ 2.95
8
0.50 0.40 0.30 12 MAX 0.80 MAX 0.65 NOM 0.05 MAX 0.02 NOM SEATING PLANE 0.30 0.23 0.18 0.20 REF COPLANARITY 0.08
17 16
9
3.50 REF
1.00 0.90 0.80
COMPLIANT TO JEDEC STANDARDS MO-220-VHHD-2
Exposed paddle should be soldered to the most negative supply of the ADN284 (ADN2844 also available as bare die)
-12-
REV. 0
C02764-0-4/03(0)

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