10.709 Gbps Laser Diode
a
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
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
CC
IMPD
*
*
V
CC
GND
IMPDMON2
IMMON
IMPDMON
CONTROL
ERCAP PAVCAP
IDTONE
IBMON
V
MPD
IMPD2
GND
MODE
ALS
PSET
GND
ERSET
GND
*ADN2850 OR ADN2860 OPTICAL SUPERVISOR
FAIL
ADN2844
DEGRADE
ADN2843
D_IMOD
GND
IMOD_CTRL
IBIAS_CTRL
ASET
IMODN
V
V
CC
ALS
V
CC
ADN2845
GND
GND
CC
LD
IMODP
DATAP
DATAN
IBIAS
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 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 © 2003 Analog Devices, Inc. All rights reserved.
ADN2843–SPECIFICATIONS
(VCC = 3.0 V to 3.6 V, All specifications T
values as specified at 25C.)
MIN
to T
, unless otherwise noted. Typical
MAX
Parameter Min Typ Max Unit Conditions
LASER BIAS (BIAS)
Output Current I
Compliance Voltage 1.2 V
I
during ALS 10 A See Note 1
BIAS
ALS Shutdown Response Time 10 s
BIAS
380mA
– 1.0 V
CC
MODULATION CURRENT (IMODP, IMODN) See Note 2
Output Current I
Compliance Voltage 1.2 V
I
during ALS 10 A
MOD
Rise Time 25 ps
MOD
580mA
CC
V
Fall Time 23 ps
Random Jitter 170 fs rms See Note 3
Total Jitter 7.41 ps p-p See Note 4
POWER SET INPUT (PSET)
External Capacitance 80 pF See Note 5
Voltage 1.15 1.35 V
EXTINCTION RATIO SET INPUT (ERSET)
Allowable Resistance Range 1.5 25 k
Voltage 1.15 1.35 V
ALARM SET (ASET)
Allowable Resistance Range 1.2 13.2 k
Voltage 1.15 1.35 V
Hysteresis 5 %
CONTROL LOOP
Time Constant 0.22 s
DATA INPUTS (DATAP, DATAN)
V p-p (Single-Ended Peak-to-Peak) 300 800 mV
Input Impedance
(Single-Ended)
50
LOGIC INPUTS (ALS, MODE)
V
IH
V
IL
2.4 V
0.8 V
ALARM OUTPUTS (Internal 30 k to VCC)
V
OH
V
OL
2.4 V
0.4 V
IDTONE
f
IN
Input Current Range 50 4000 A
10 1000 kHz
Voltage on IDTONE VCC – 2 V
MONITOR PD (MPD, MPD2)
Current 50 1200 A
Input Voltage 1.65 V
IBMON, IMMON, IMPDMON, IMPDMON2
IBMON, IMMON Division Ratio 100 A/A
IMPDMON, IMPDMON2 1 A/A
IMPDMON to IMPDMON2 Matching 2 %
Measured at 1200 A
Compliance Voltage 0 VCC – 1.5 V
SUPPLY
V
CC
I
(ADN2844) 36 mA See Note 6
CC
I
(ADN2845) 75 mA See Note 6
CC
NOTES
1
In ALS mode current is sourced to the laser from the I
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 213 – 1 PRBS with 80 CIDs pattern at 10.7 Gbps rate.
5
Max capacitance refers to capacitance of photodiode and other parasitic capacitance.
6
I
= 0, I
BIAS
Specifications subject to change without notice.
= 0 (when ALS is asserted). See Power Dissipation section on page 7 for calculation of complete power dissipation.
MOD
pin, which reverse biases the laser.
BIAS
3.0 3.3 3.6 V
REV. 0–2–
ADN2843
ABSOLUTE MAXIMUM RATINGS*
(TA = 25°C, unless otherwise noted.)
VCC to GND . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.2 V
Digital Inputs (ALS, MODE) . . . . . . . . –0.5 V to V
IMODN, IMODP . . . . . . . . . . . . . . . . . . . . . . . . . V
+ 0.3 V
CC
+ 1.2 V
CC
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 . . . . . . . . . . . . . . . . . . . . . . . . . . .–40°C to +85°C
Storage Temperature Range . . . . . . . . . . . . . –65°C to +150°C
Junction Temperature (T
*Stresses above those listed under Absolute Maximum Ratings may cause perma-
nent 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.
Max) . . . . . . . . . . . . . . . . . . 150°C
J
ADN2844 METALLIZATION PHOTOGRAPH
IBMON
IMMON
ALS
IDTONE
GND
ORDERING GUIDE
Temperature Package
Model Range Option
ADN2843CHIPSET –40°C to +85°C ADN2844 Control
Loop: 32-Lead LFCSP
ADN2845 Data
Switch: Dice
ADN2843CHIPSET-B –40°C to +85°C ADN2844 Control
Loop: Dice
ADN2845 Data
Switch: Dice
EVAL-ADN2843 Evaluation Board
GND
DEGRADE
GND
FAIL
V
IBIAS_CTRL
GND
IMOD_CTRL
D_IMOD
GND
GND
CC
ASET
ERSET
PSET
GND
3000m
IMPD
IMPDMON
IMPD2
IMPDMON2
GND
GND
GND
MODE
PAV CAP
ERCAP
V
CC
GND
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.
2390m
REV. 0
–3–
ADN2843
ADN2845 METALLIZATION PHOTOGRAPH
DATAN
1340m
(20m)
DATAP
GND
NC
GND
V
CC
V
CC
GNDV
CC
GNDIBIAS_CTRLALS IMOD_CTRL
1140m
(20m)
PIN CONFIGURATIONS
V
CC
(IMODN TERM)
NC
IMODP
IBIAS
NC
ASET
ERSET
PSET
GND
IMPD
IMPDMON
IMPDMON2
IMPD2
D_IMOD
GND
GND
32 31 30 29
1
2
3
4
5
6
7
8
ADN2844
BOND PAD SIZE: >115m
BOND PAD PITCH: >104m
DIE SIZE: 3000m 2390m
9101112
CC
V
GND
ERCAP
GND
IMOD_CTRL
28 27 26
13 14 15
GND
MODE
PAVCAP
VCCIBIAS_CTRL
GND
25
16
GND
GND
24
IDTONE
23
IBMON
22
IMMON
21
ALS
20
FAIL
19
DEGRADE
18
GND
17
GND
DATAN
GND
NC
GND
DATAP
CC
V
VCCV
1
ADN2845
PAD PITCH: 200m
MAXIMUM DIE SIZE: 1.16mm
1.36mm
DIE THICKNESS: 0.25mm
SINGLE PAD SIZE: 92m 92m
DOUBLE PAD SIZE: 151m 92m
ALS
IMOD_CTRL
CC
GND
GND
IBIAS_CTRL
V
CC
(IMODN TERM)
NC
IMODP
IBIAS
NC
REV. 0–4–
ADN2844 PIN FUNCTION DESCRIPTIONS
Pin No. Mnemonic Function
1 ASET Alarm Current Threshold Set (Should be Terminated with a 1.2 k
Resistor when Not Used)
2 ERSET Extinction Ratio Current Set
3 PSET Average Optical Power Set
4GND Negative Supply
5 IMPD Monitor Photodiode Current Input (Tie to GND when Not in Use)
6IMPDMON Mirrored Current from IMPD (Tie to V
7 IMPDMON2 Mirrored Current from IMPD2 (For Optional Use with Two MPDs, Tie to V
when Not in Use)
CC
when Not in Use)
CC
8IMPD2 Optional Second MPD Current Input (Tie to GND when Not in Use)
9GND Negative Supply
10 V
CC
Positive Supply
11 ERCAP Extinction Ratio Loop Capacitor
12 PAVCAP Average Power Loop Capacitor
13 MODE Control Loop Operating Mode Logic Input (Should Not Be Left Floating)
14, 15, 17 GND Negative Supply
18, 31, 32 GND Negative Supply
16 GND Negative Supply
19 DEGRADE DEGRADE Alarm Output, Open Collector, Active High
20 FAIL FAIL Alarm Output, Open Collector, Active High
21 ALS Automatic Laser Shutdown Logic Input (Should Not Be Left Floating)
22 IMMON Modulation Current Mirror Output, Current Source from V
23 IBMON Bias Current Mirror Output, Current Source from V
CC
CC
24 IDTONE ID Tone Input Current (Tie to VCC when Not in Use)
25 GND Negative Supply
26 V
CC
Positive Supply
27 IBIAS_CTRL Control Output Current Sink
28 GND Negative Supply
29 IMOD_CTRL Control Output Current Sink
30 D_IMOD Control Output Current Sink
ADN2843
ADN2845 PIN FUNCTION DESCRIPTIONS
Pin No. Mnemonic Function
1 DATAN AC-Coupled CML Data, Negative Differential Terminal
2GND Negative Supply
3, 13 NC No Connect, Leave Floating
4GND Negative Supply
5 DATAP AC-Coupled CML Data, Positive Differential Terminal
6 ALS Automatic Laser Shutdown Logic Input
7 IMOD_CTRL Modulation Current Control Input (Control Circuit Sinks IMOD/10 from Pin to GND)
8IBIAS_CTRL BIAS Current Control Input (Control Circuit Sinks IBIAS/10 from Pin to GND)
9GND Negative Supply
10 NC No Connect, Leave Floating
11 IBIAS BIAS Current
12 IMODP Modulation Current
14 V
CC
VCC Connection for IMODN Termination Resistor
15 GND Negative Supply
16–18 V
CC
Positive Supply
REV. 0
–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, I
, and slope in the linear region
TH
beyond the threshold current, referred to as the slope efficiency, LI.
ER = P1
P0
= P1 + P0
P
P1
P
AV
OPTICAL POWER
P0
AV
2
P
P
LI =
I
I
ITHCURRENT
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 D_IMOD
Mode Pin Setting Pin Connected to
AHIGH IBIAS
B LOW IBIAS_CTRL
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 I
BIAS
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 I
, the ADN2843
BIAS
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
R
is used to set the average power. The potentiometer R
PSET
ERSET
is used to set the extinction ratio. The internal control loops
force the PSET and ERSET pins to 1.23 V above GND. For
initial setup, R
PSET
and R
may be calculated using the
ERSET
following formulas:
The PSET resistor is given by the following formulas:
123.
V
I
AV
W
()
where I
R
PSET
is average MPD current.
AV
=
The value of the ERSET resistor is a function of the operation
mode of the ADN2843 as follows:
For Mode A:
ER
RR
=¥
ERSET PSET
ER
+ 1
1–
For Mode B:
R
PSET
=¥
will change from laser diode to laser
and R
need to be adjusted for each
PSET
Note that I
ERSET
diode, therefore R
R
and I
ERSET
ERSET
PSET
laser diode. When tuning the laser diode, R
adjusted first with R
set, R
R
PSET
is adjusted to set the desired extinction ratio, and
ERSET
is again adjusted to re-establish the desired average power.
Once the values R
at 25 k. Once the average power is
ERSET
PSET
and R
have been adjusted to set the
ERSET
ER
ER
+21
1–
PSET
should be
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
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 I
exceeds the respective DEGRADE and FAIL thresh-
BIAS
olds. 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:
50 45
ImAsoI mA
==
FAIL DEGRADE
I
R
I
== =
ASET
100
123 123
== =
ASET
50
FAIL
..
I
ASET
mA
100
V
500
500
V
A
A
246
. W
k
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.
REV. 0–6–
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
The alarm voltages are open collector outputs. An internal
pull-up resistor of 30k
value to V
. However, this can be overdriven with an external
CC
that is used to pull the logic high
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-V
must be below the V
DATA INPUTS
used for the ADN2843.
CC
alarm output levels
CC
Figure 2 shows a simplified schematic of the ADN2845 data
inputs. The data inputs are terminated via the equivalent of a
internal resistor between DATAN and DATAP. This
100
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.
DATAN
DATAP
25
25
25
25
2k
ADN2845
INTERNAL
REFERENCE
Figure 2. Simplified Schematic of Data Inputs
MONITOR CURRENTS
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 V
CC
.
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 V
MPD CURRENT
CC
.
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 moni-
REV. 0
–7–
tor photodiode cathode should be connected directly to the PSET
node, and IMPDMON and IMPDMON2 should be tied to V
CC
.
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 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
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 I
to 10% of maximum I
MOD
. The IDTONE
MOD
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 I
current. To ratio the IDTONE current to I
MOD
MOD
, 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 V
to properly disable it.
CC
Note that using IDTONE during transmission may cause optical
eye degradation.
AUTOMATIC LASER SHUTDOWN (ALS)
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 I
pin, which reverse biases the laser and ensures
BIAS
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
The power dissipation of the ADN2845 can be calculated using
the following expressions:
ImA ImA ImA
=+¥
75 1 75 0 3
CC MOD BIAS
=¥
PV I A V I A V I A
CC CC IMOD MOD IBIAS BIAS
where V
V
IMOD
is the average voltage on the I
IBIAS
..
+¥
()
is the average voltage on the IMOD pin, and
+¥
()
/
()
pin.
BIAS
()
+¥
2
()
ADN2843
**
1k
CC
10nF
1518
CC
NC
IMODP
IBIAS
NC
IBIAS_CTRL
96
IBIAS_CTRL
V
CC
100F TANTALUM
GND
14
10nF
10
GND
V
CC
10nF
CC
V
GND
IDTONE
IBMON
IMMON
ALS
FAIL
DEGRADE
GND
V
CC
V
24
V
CC
MPD
CC
**
1k
1k
**
10k
V
V
V
CC
CC
10nF
V
CC
10nF
10nF
32 25
GND
GND
1
ASET
ERSET
PSET
1
5
ALS
D_IMOD
DATAN
GND
NC
GND
DATAP
VCCV
IMODNTERM
ADN2845
IMOD_CTRL
GND
IMOD_CTRL
ADN2844
GND
IMPD
IMPDMON
**
V
CC
IMPDMON2
IMPD2
8
CC
ERCAP
PAVCAP
MODE
GND
V
9 16
22nF
10nF
NOTES
*FOR DIGITAL PROGRAMMING, THE ADN2850 OR ADN2860 OPTICAL SUPERVISOR CAN BE USED.
**OPTIONAL MONITORING OF CURRENTS.
22nF
V
CC
GND
V
CC
GND
GND
17
GND
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 V
(Pin 14). Ribbon bonding can be used to reduce
CC
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 V
CC
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 V
rather than GND.
CC
• 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 recommended substrate connection is to GND. However, the performance is not affected by connecting the substrate to V
CC.
REV. 0–8–
ADN2843
10nF
10nF
V
CC
V
V
CC
10nF 10nF
V
CC
VCCV
CC
1
DATAN
GND
IMODNTERM
ADN2845
NC
GND
5
DATAP
ALS GND
IMOD_CTRL
CC
1518
NC
IMODP
IBIAS
GND
IBIAS_CTRL
96
V
CC
100F TANTALUM
GND
14
10nF
10
V
CC
V
CC
V
CC
MPD
10nF
32 25
CC
V
IDTONE
IBMON
IMMON
ALS
FAIL
DEGRADE
GND
GND
GND
GND
GND
V
CC
24
17
GND
LBWSET
1
ASET
D_IMOD
GND
IMOD_CTRL
IBIAS_CTRL
ERSET
PSET
**
ADN2844
GND
IMPD
IMPDMON
1k
**
IMPDMON2
V
CC
IMPD2
8
CC
ERCAP
PAVCAP
MODE
GND
V
9 16
10nF
NOTES
*FOR DIGITAL PROGRAMMING, THE ADN2850 OR ADN2860 OPTICAL SUPERVISOR CAN BE USED.
**OPTIONAL MONITORING OF CURRENTS.
22nF
22nF
V
CC
GND
V
CC
Figure 4. ADN2843 Application Circuit (Mode B)
10k
**
1k
1k
**
REV. 0
–9–
ADN2843
PARALLEL PLATE
DECOUPLING
CAPACITOR
GROUND PLANE
MPD
50 TRANSMISSION LINE
GROUND PLANE
18 15
V
V
CC
CC
DATAN
1
AGN D
ADN2845
AGN D
DATAP
5
AGN DV
CC
IMODNTERM
BACK FACET LIGHT
14
V
CC
IMODP
IBIAS
10
AGN DALS IMOD_CTRL IBIAS_CTRL
96
IBIAS OUTPUT INDUCTOR
PARALLEL PLATE
DECOUPLING
CAPACITORS
CERAMIC WITH GOLD
SURFACE THAT CONTACTS
THE LASER’S ANODE
LASER LIGHT
LASER
NOTES
• FOR OPTIMUM PERFORMANCE, RIBBON BONDS ARE RECOMMENDED ON PADS 1, 5, 12, AND 14. WIRES ARE 3 MIL OR 5 MIL RIBBONS <400m
• LONG. ALL OTHER PINS CAN BE ROUND WIRE <1mm.
• LASER’S ANODE IS CONNECTED TO V
• 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.
THROUGH GOLD LAYER ON TOP OF CERAMIC STANDOFF. STANDOFF MINIMIZES LENGTH OF PAD
CC
Figure 5. Recommended Layout
Figure 6. 10 Gbps Optical Diagram Provided Courtesy of NEL.
= 0 dBm, ER = 5 dB, PRBS 31 Pattern.
P
AV
REV. 0–10–
ADN2844
ADN2843
DIE PAD COORDINATES
(With Origin in the Center of the Die)
ADN2845
Pad Number Pad Name X (m) Y (m)
1 ASET 1014.00 –1019.00
2 ERSET 769.00 –1019.00
3 PSET 486.00 –1019.00
4 GND 186.00 –1019.00
5IMPD –132.00 –1019.00
6 IMPDMON –479.00 –1019.00
7 IMPDMON2 –811.00 –1019.00
8 IMPD2 –1056.00 –1019.00
9 GND –1339.00 –877.00
10 V
11 ERCAP –1339.00 –429.00
CC
–1339.00 –672.00
12 PAVCAP –1339.00 –204.00
13 MODE –1339.00 91.00
14 GND –1339.00 335.00
15 GND –1339.00 580.00
16 GND –1339.00 824.00
17 GND –1051.00 1019.00
18 GND –761.00 1019.00
19 DEGRADE –476.00 1019.00
20 FAIL –207.00 1019.00
21 ALS 102.00 1019.00
22 IMMON 387.00 1019.00
23 IBMON 653.00 1019.00
24 IDTONE 904.00 1019.00
25 GND 1359.00 995.00
26 V
CC
1359.00 781.00
27 IBIAS_CNTRL 1359.00 523.00
28 GND 1359.00 317.00
29 IMOD_CTRL 1359.00 –29.00
30 D_IMOD 1359.00 –294.00
31 GND 1359.00 –562.00
32 GND 1359.00 –807.00
Pad Number Pad Name X (m) Y (m)
1 DATAN –500.00 400.00
2 GND* –500.00 222.00
3NC–500.00 0.00
4 GND* –500.00 –222.00
5 DATAP –500.00 –400.00
6 ALS –300.00 –600.00
7IMOD_CTRL –100.00 –600.00
8 IBIAS_CTRL 100.00 –600.00
9 GND* 300.00 –600.00
10 NC* 500.00 –400.00
11 IBIAS 500.00 –200.00
12 IMODP* 500.00 –30.00
13 NC* 500.00 178.00
14 V
15 GND* 300.00 600.00
(IMODN)* 500.00 378.00
CC
16 VCC* 100.00 600.00
17 V
* –100.00 600.00
CC
18 VCC* –300.00 600.00
*
Denotes double bond pad.
REV. 0
–11–
ADN2843
OUTLINE DIMENSIONS
32-Lead Lead Frame Chip Scale Package [LFCSP]
5 mm 5 mm
(CP-32)
Dimensions shown in millimeters
PIN 1
INDICATOR
1.00
0.90
0.80
12 MAX
SEATING
PLANE
5.00
BSC SQ
TOP
VIEW
0.80 MAX
0.65 NOM
0.30
0.23
0.18
COMPLIANT TO JEDEC STANDARDS MO-220-VHHD-2
4.75
BSC SQ
0.20 REF
0.05 MAX
0.02 NOM
0.60 MAX
0.50
BSC
0.50
0.40
0.30
COPLANARITY
0.08
25
24
17
16
0.60 MAX
BOTTOM
VIEW
3.50
REF
PIN 1
32
9
INDICATOR
1
3.25
3.10
SQ
2.95
8
Exposed paddle should be soldered to the most negative supply of the ADN284
(ADN2844 also available as bare die)
C02764–0–4/03(0)
–12–
REV. 0
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