AD EVAL-ADN2843 10.709 gbps laser diode driver chipset Datasheet

a
10.709 Gbps Laser Diode
Driver Chipset
ADN2843
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
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 [email protected].
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.
APPLICATIONS
SONET OC-192, SDH STM-64
Supports 10.667 Gbps and 10.709 Gbps FEC Rates
10 Gb Ethernet IEEE802.3ae
FAIL
DEGRADE
IBMON
IMPDMON2
VCC
IMMON
VCC
IMPDMON
FUNCTIONAL BLOCK DIAGRAM
VCC
MPD
VCC
VCC
LD
ADN2843
ADN2844
ADN2845
IMPD
IMODP
IMODN
IMPD2
GND
MODE
DATAP
CONTROL
GND
IMOD_CTRL
ALS
DATAN
D_IMOD
PSET
*
IBIAS
IBIAS_CTRL
GND
ERSET
*
GND
ERCAP
PAVCAP
ASET
ALS
GND IDTONE
GND
GND
*ADN2850 OR ADN2860 OPTICAL SUPERVISOR
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.
V to 3.6 V, All specifications T
at 25C.)
ADN2843–SPECIFICATIONS (Vvalues= 3.0as specified
CC
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
MIN
Min
Typ
3
1.2
to TMAX, unless otherwise noted. Typical
Max
Unit
Conditions
80
VCC – 1.0
10
10
mA
V
A
s
See Note 1
80
VCC
10
mA
V
A
ps
ps
fs rms
ps p-p
See Note 2
5
1.2
25
23
170
7.41
POWER SET INPUT (PSET)
External Capacitance
Voltage
1.15
80
1.35
pF
V
EXTINCTION RATIO SET INPUT (ERSET)
Allowable Resistance Range
Voltage
1.5
1.15
25
1.35
k
V
1.2
1.15
13.2
1.35
5
k
V
%
0.22
s
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)
300
LOGIC INPUTS (ALS, MODE)
VIH
2.4
800
mV
0.8
V
0.4
V
10
50
VCC – 2
1000
4000
kHz
A
V
50
1200
1.65
A
V
2
VCC – 1.5
A/A
A/A
%
V
50
2.4
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)
See Note 5
V
VIL
ALARM OUTPUTS (Internal 30 k to V CC)
VOH
See Note 3
See Note 4
100
1
0
3.0
3.3
75
3.6
36
V
mA
mA
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.
–2–
REV. 0
ADN2843
ABSOLUTE MAXIMUM RATINGS*
ORDERING GUIDE
(TA = 25°C, unless otherwise noted.)
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 . . . . . . . . . . . . . . . . . . . . . . . . . . . –40°C to +85°C
Storage Temperature Range . . . . . . . . . . . . . –65°C to +150°C
Junction Temperature (TJ Max) . . . . . . . . . . . . . . . . . . 150°C
Temperature
Range
Model
ADN2843CHIPSET
Package
Option
–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
*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.
GND
GND
DEGRADE
FAIL
ALS
IMMON
IBMON
IDTONE
ADN2844 METALLIZATION PHOTOGRAPH
GND
GND
VCC
GND
IBIAS_CTRL
GND
GND
MODE
IMOD_CTRL
PAVCAP
D_IMOD
ERCAP
GND
VCC
GND
IMPD2
IMPDMON2
IMPDMON
IMPD
GND
PSET
ERSET
ASET
GND
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.
REV. 0
–3–
2390␮m
ADN2843
ADN2845 METALLIZATION PHOTOGRAPH
VCC
VCC
VCC
GND
VCC
(IMODN TERM)
DATAN
GND
NC
1340m
(20m)
IMODP
NC
IBIAS
GND
NC
DATAP
ALS IMOD_CTRL IBIAS_CTRL GND
1140m
(20m)
GND
IBIAS_CTRL
VCC
GND
29
28
27
26
25
GND
IMOD_CTRL
30
VCC
D_IMOD
31
VCC
GND
32
VCC
GND
PIN CONFIGURATIONS
1
23
IBMON
PSET 3
22
IMMON
21
ALS
20
FAIL
19
DEGRADE
IMPDMON2 7
18
GND
IMPD2 8
17
GND
ADN2844
GND 4
BOND PAD SIZE: >115m
BOND PAD PITCH: >104m
DIE SIZE: 3000m 2390m
IMPD 5
9
10
11
12
13
14
15
16
GND
VCC
ERCAP
PAVCAP
MODE
GND
GND
GND
IMPDMON 6
VCC
(IMODN TERM)
DATAN
GND
NC
GND
ADN2845
NC
PAD PITCH: 200m
MAXIMUM DIE SIZE: 1.16mm 1.36mm
DIE THICKNESS: 0.25mm
SINGLE PAD SIZE: 92m 92m
DOUBLE PAD SIZE: 151m 92m
DATAP
–4–
IMODP
IBIAS
NC
GND
ERSET 2
IBIAS_CTRL
IDTONE
IMOD_CTRL
24
ALS
ASET 1
REV. 0
ADN2843
ADN2844 PIN FUNCTION DESCRIPTIONS
Pin No.
Mnemonic
Function
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
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
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.
Mnemonic
Function
1
2
3, 13
4
5
6
7
8
9
10
11
12
14
15
16–18
DATAN
GND
NC
GND
DATAP
ALS
IMOD_CTRL
IBIAS_CTRL
GND
NC
IBIAS
IMODP
VCC
GND
VCC
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
REV. 0
–5–
ADN2843
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:
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.
The PSET resistor is given by the following formulas:
1.23 V
RPSET =
(W )
I AV
where IAV is average MPD current.
ER = P1
P0
PAV = P1 + P0
2
OPTICAL POWER
P1
The value of the ERSET resistor is a function of the operation
mode of the ADN2843 as follows:
P
PAV
LI =
For Mode A:
P
I
R ERSET = R PSET ¥
I
ER + 1
ER – 1
For Mode B:
P0
ITH
R ERSET =
CURRENT
Figure 1. Laser Transfer Function
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.
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.
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.
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
MODE
Pin Setting
D_IMOD
Pin Connected to
A
B
HIGH
LOW
IBIAS
IBIAS_CTRL
R PSET ER + 1
¥
2
ER – 1
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 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.
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).
Example:
I FAIL = 50 mA so I DEGRADE = 45 mA
I FAIL 50 mA
=
= 500 A
100
100
1.23 V
1.23 V
=
=
= 2.46 kW
500 A
I ASET
I ASET =
R ASET
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
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.
–6–
REV. 0
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:
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.
∑ The ASET threshold is reached.
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.
∑ 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.
DUAL MPD DWDM FUNCTION
ALARM INTERFACE
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.
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
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.
DATAN
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 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.
ADN2845
25
Note that using IDTONE during transmission may cause optical
eye degradation.
25
2k
INTERNAL
REFERENCE
AUTOMATIC LASER SHUTDOWN (ALS)
25
DATAP
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.
25
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 VCC.
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.
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.
POWER DISSIPATION
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)
MPD CURRENT
P = VCC ¥ I CC ( A) + VIMOD ¥ I MOD ( A) / 2 + VIBIAS ¥ I BIAS ( A)
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
where VIMOD is the average voltage on the IMOD pin, and
VIBIAS is the average voltage on the IBIAS pin.
–7–
ADN2843
VCC VCC VCC
VCC
100F TANTALUM
10nF
10nF
VCC 18
15 GND
VCC VCC
1 DATAN
IMODNTERM 14
NC
GND
10nF
5
DATAP
VCC
VCC
10nF
NC
ADN2845
IBIAS_CTRL
GND
IMOD_CTRL
10nF
MPD
IMODP
IBIAS
NC 10
9 GND
ALS 6
VCC
10nF
VCC
IDTONE 24
ERSET
IBMON
PSET
IMMON
**
ADN2844
*
GND
ALS
IMPD
FAIL
IMPDMON
IMPDMON2
1k
1k
10k
GND
9
GND
GND
GND 17
MODE
VCC
GND
8 IMPD2
**
DEGRADE
PAVCAP
**
VCC
ERCAP
1k
GND
*
GND
VCC
GND
IBIAS_CTRL
1 ASET
IMOD_CTRL
D_IMOD
GND
25
GND
32
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 24 mil) should
be used.
• The recommended substrate connection is to GND. However, the performance is not affected by connecting the substrate to VCC.
–8–
REV. 0
ADN2843
VCC VCC VCC
VCC
100F TANTALUM
10nF
10nF
VCC 18
15 GND
VCC
VCC VCC
10nF
GND
IBIAS_CTRL
5 DATAP
IMOD_CTRL
GND
10nF
10nF
NC
ADN2845
NC
VCC
IMODNTERM 14
1 DATAN
MPD
IMODP
IBIAS
GND 10
ALS 6
9 GND
VCC
10nF
VCC
IDTONE 24
ERSET
IBMON
PSET
*
IMMON
**
ADN2844
*
GND
ALS
IMPD
FAIL
IMPDMON
1k
GND
VCC
IBIAS_CTRL
GND
GND
ASET
IMOD_CTRL
1
D_IMOD
25
LBWSET
32
DEGRADE
**
IMPDMON2
GND
9
GND
GND
GND
GND 17
MODE
PAVCAP
VCC
IMPD2
GND
8
ERCAP
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 4. ADN2843 Application Circuit (Mode B)
REV. 0
–9–
**
10k
1k
1k
ADN2843
PARALLEL PLATE
DECOUPLING
CAPACITOR
PARALLEL PLATE
DECOUPLING
CAPACITORS
GROUND PLANE
18
VCC
1
MPD
DATAN
AGND
15
VCC
VCC
AGND
VCC
IMODNTERM
BACK FACET LIGHT
ADN2845
IMODP
CERAMIC WITH GOLD
SURFACE THAT CONTACTS
THE LASER’S ANODE
LASER LIGHT
LASER
IBIAS
AGND
5
14
10
DATAP
ALS IMOD_CTRL IBIAS_CTRL AGND
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 <400m
• 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.
–10–
REV. 0
ADN2843
DIE PAD COORDINATES
(With Origin in the Center of the Die)
ADN2845
ADN2844
Pad Number
Pad Name
X (m)
Y (m)
Pad Number
Pad Name
X (m)
Y (m)
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
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
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
–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
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
DATAN
GND*
NC
GND*
DATAP
ALS
IMOD_CTRL
IBIAS_CTRL
GND*
NC*
IBIAS
IMODP*
NC*
VCC (IMODN)*
GND*
VCC*
VCC*
VCC*
–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
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
REV. 0
*Denotes
–11–
double bond pad.
ADN2843
OUTLINE DIMENSIONS
32-Lead Lead Frame Chip Scale Package [LFCSP]
5 mm 5 mm
(CP-32)
5.00
BSC SQ
0.60 MAX
PIN 1
INDICATOR
12 MAX
32 1
0.50
BSC
4.75
BSC SQ
3.25
3.10 SQ
2.95
BOTTOM
VIEW
0.50
0.40
0.30
1.00
0.90
0.80
PIN 1
INDICATOR
0.60 MAX
25
24
TOP
VIEW
C02764–0–4/03(0)
Dimensions shown in millimeters
17
16
9
8
3.50
REF
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
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