Analog Devices ADN2841ACP-48-RL7, ADN2841ACP-48, ADN2841ACP-32-RL7, ADN2841ACP-32-RL, ADN2841ACP-32 Datasheet
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.
a
ADN2841
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 © Analog Devices, Inc., 2001
Dual-Loop 50 Mbps–2.7 Gbps
FUNCTIONAL BLOCK DIAGRAM
CONTROL
DATA P
DATA N
CLKP
CLKN
IMODP
IBIAS
LD
V
CC
GND
ASET
I
MOD
I
BIAS
GNDGND
GND
GND
GND
LBWSETIDTONE
PAVCAPERCAP
ERSET
PSET
IMPD2
IMPD
V
CC
MPD
IBMON
IMMON
IMPDMON
IMPDMON2
ALS
FAIL
DEGRADE
CLKSEL
V
CC
GND
V
CC
ADN2841
IMODN
FEATURES
50 Mbps to 2.7 Gbps Operation
Typical Rise/Fall Time 80 ps
Bias Current Range 2 to 100 mA
Modulation Current Range 5 to 80 mA
Monitor Photodiode Current 50 A to 1200 A
Closed-Loop Control of Power and Extinction Ratio
Laser Fail and Laser Degrade Alarms
Automatic Laser Shutdown, ALS
Dual MPD Functionality for DWDM
Optional Clocked Data
Full Current Parameter Monitoring
5 V Operation
48-Lead LFCSP Package
32-Lead LFCSP Package (Reduced Functionality)
APPLICATIONS
DWDM Dual MPD Wavelength Fixing
SONET OC-1/3/12/48
SDH STM-1/4/16
Fiber Channel
Gigabit Ethernet
GENERAL DESCRIPTION
The ADN2841 uses a unique control algorithm to control both
average power and extinction ratio of the laser diode (LD) after
initial factory set up. External component count and PCB area are
low as both power and extinction ratio control are fully integrated.
Programmable alarms are provided for laser fail (end of life) and
laser degrade (impending fail).
The ADN2841 has circuitry for a second monitor photodiode
which enables DWDM wavelength control.
Laser Diode Driver
REV. 0
–2–
ADN2841–SPECIFICATIONS
(VCC = 5 V 10%. All specifications T
MIN
to T
MAX
unless otherwise noted1. Typical
values as specified at 25C.)
Parameter Min Typ Max Unit Conditions/Comments
LASER BIAS (BIAS)
Output Current I
BIAS
2 100 mA
Compliance Voltage 1.2
V
CC
V
I
BIAS
during ALS 0.1 mA
ALS Response Time 10 µs
CCBIAS Compliance Voltage 1.2 V
MODULATION CURRENT (IMODP, IMODN)
Output Current I
MOD
580mA
Compliance Voltage 1.8 V
CC
V
I
MOD
during ALS 0.1 mA
Rise Time 80 120 ps
Fall Time 80 120 ps
Jitter 20 ps p-p
Pulsewidth Distortion 18 ps
MONITOR PD (MPD, MPD2)
Current 50 1200 µA Average Current
Input Voltage 1.6 V
POWER SET INPUT (PSET)
Capacitance 80 pF
Input Current 50 1200 µA Average Current
Voltage 1.15 1.23 1.35 V
EXTINCTION RATIO SET INPUT (ERSET)
Allowable Resistance Range 1.2 25 kΩ
Voltage 1.15 1.23 1.35 V
ALARM SET (ASET)
Allowable Resistance Range 1.2 25 kΩ
Voltage 1.15 1.23 1.35 V
Hysteresis 5 %
CONTROL LOOP
Time Constant 0.22 sec (LBWSET = GND)
2.25 sec (LBWSET = VCC)
DATA INPUTS (DATAP, DATAN, CLKP, CLKN)
AC-Coupled
2
V p-p (Single-Ended peak-to-peak) 100 500 mV
Input Impedance 50 Ω
t
SETUP
3
150 95 ps
t
HOLD
3
0 –70 ps
LOGIC INPUTS (ALS, LBWSET, CLKSEL)
V
IH
2.4 V
V
IL
0.8 V
ALARM OUTPUTS (Internal 30 kΩ Pull-up)
V
OH
2.4 V
V
OL
0.8 V
IDTONE
Compliance Voltage VCC– 1.5 V User to Supply Current
Sink in the range 50 µA
to 4 mA
2
f
IN
4
0.01 1 MHz
I
I
RATIO
OUT
IN
REV. 0
–3–
ADN2841
Parameter Min Typ Max Unit Conditions/Comments
IBMON, IMMON, IMPDMON, IMPDMON2
IBMON, IMMON Division Ratio 100 A/A
IMPDMON, IMPDMON2 1 A/A
IMPDMON to IMPDMON2 Matching 1 % IMPD = 1200 µA
Compliance Voltage 0 VCC– 1.2 V
SUPPLY
I
CC
5
0.05 A I
BIAS
= I
MOD
= 0
V
CC
6
4.5 5.0 5.5 V
NOTES
1
Temperature Range: –40°C to +85°C
2
When the voltage on DATAP is greater than the voltage on DATAN, the modulation current flows in the IMODP pin.
3
Guaranteed by design and characterization. Not production tested.
4
IDTONE may cause eye distortion.
5
ICC for power calculation is the typical ICC given.
6
All V
CCS
should be shorted together.
Specifications subject to change without notice.
ABSOLUTE MAXIMUM RATINGS
1
(TA = 25°C unless otherwise noted.)
VCCto GND . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 V
Operating Temperature Range
Industrial . . . . . . . . . . . . . . . . . . . . . . . . . . –40°Cto+85°C
Storage Temperature Range . . . . . . . . . . –65°C to +150°C
Junction Temperature (T
J MAX
) . . . . . . . . . . . . . . . . . . 150°C
48-Lead LFCSP Package
Power Dissipation . . . . . . . . . . . . . . .(T
J MAX
– TA)/θJA mW
θ
JA
Thermal Impedance2 . . . . . . . . . . . . . . . . . . . . 25°C/W
Lead Temperature (Soldering for 10 sec) . . . . . . . . 300°C
ORDERING GUIDE
Model Temperature Range Package Description
ADN2841ACP-32 –40°C to +85°C 32-Lead LFCSP
ADN2841ACP-48 –40°C to +85°C 48-Lead LFCSP
ADN2841ACP-32-RL –40°C to +85°C 32-Lead LFCSP
ADN2841ACP-32-RL7 –40°C to +85°C 32-Lead LFCSP
ADN2841ACP-48-RL –40°C to +85°C 48-Lead LFCSP
32-Lead LFCSP Package
Power Dissipation . . . . . . . . . . . . . . . (T
JMAX–TA
)/θJAmW
θ
JA
Thermal Impedance2 . . . . . . . . . . . . . . . . . . . . 32°C/W
Lead Temperature (Soldering for 10 sec) . . . . . . . . . 300°C
NOTES
1
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. Transient currents of
up to 100 mA will not cause SCR latch-up.
2
θJA is defined when the part is soldered onto a four-layer board.
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 ADN2841 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.
WARNING!
ESD SENSITIVE DEVICE
SETUP
t
S
HOLD
t
H
DATA P/N
CLKP
Figure 1. Setup and Hold Time
REV. 0
ADN2841
–4–
PIN FUNCTION DESCRIPTIONS
Pin No.
48-Lead 32-Lead Mnemonic Function
1 GND Supply Ground
2 1 LBWSET Select Low Loop Bandwidth (Active = VCC)
3 2 ASET Alarm Current Threshold Setting Pin
4 3 ERSET Extinction Ratio Set Pin
5 4 PSET Average Optical Power Set Pin
6 GND Ground
7 5 IMPD Monitor Photodiode Input
8 6 IMPDMON Mirrored Current from Monitor Photodiode
9 IMPDMON2 Mirrored Current from Monitor Photodiode 2 (for use with two MPDs)
10 IMPD2 Monitor Photodiode Input 2– (for use with two MPDs)
11 7 GND4 Supply Ground
12 8 VCC4 Supply Voltage
13 9 ERCAP Extinction Ratio Loop Capacitor
14 10 PAVCAP Average Power Loop Capacitor
15 GND Ground
16 11 VCC1 Supply Voltage
17 GND1 Supply Ground
18 12 DATAN Data, Negative Differential Terminal
19 13 DATAP Data, Positive Differential Terminal
20 14 GND1 Supply Ground
21 15 CLKP Data Clock Positive Differential Terminal, used if CLKSEL = V
CC
22 16 CLKN Data Clock Negative Differential Terminal, used if CLKSEL = V
CC
23 GND Ground
24 GND Ground
25 GND Ground
26 17 CLKSEL Clock Select (Active = V
CC
), used if data is clocked into chip
27 18 DEGRADE DEGRADE Alarm Output
28 19 FAIL FAIL Alarm Output
29 20 ALS Automatic Laser Shutdown
30 21 VCC3 Supply Voltage
31 22 GND3 Supply Ground
32 23 IMMON Modulation Current Mirror Output
33 24 IBMON Bias Current Mirror Output
34 GND2 Supply Ground
35 IDTONE IDTONE (Requires external current sink to ground)
36 GND2 Supply Ground
PIN CONFIGURATIONS
48-Lead LFCSP
PIN 1
INDICATOR
ADN2841
TOP VIEW
(Not to Scale)
GND2 37
VCC2 38
IMODN 39
IMODN 40
GND2 41
IMODP 42
IMODP 43
GND2 44
GND2 45
IBIAS 46
IBIAS 47
CCBIAS 48
GND 1
LBWSET 2
ASET 3
ERSET 4
PSET 5
GND 6
IMPD 7
IMPDMON 8
IMPDMON2 9
IMPD2 10
GND4 11
VCC4 12
24 GND
23 GND
22 CLKN
21 CLKP
20 GND1
19 DATAP
18 DATAN
17 GND1
16 VCC1
15 GND
14 PAVCAP
13 ERCAP
36 GND2
35 IDTONE
34 GND2
33 IBMON
32 IMMON
31 GND3
30 VCC3
29 ALS
28 FAIL
27 DEGRADE
26 CLKSEL
25 GND
32-Lead LFCSP
PIN 1
INDICATOR
TOP VIEW
(Not to Scale)
LBWSET 1
ASET 2
ERSET 3
32 CCBIAS
ERCAP 9
PAVCAP 10
VCC1 11
DATA N 12
DATA P 13
GND1 14
CLKP 15
CLKN 16
PSET 4
IMPD 5
IMPDMON 6
GND4 7
VCC4 8
31 IBIAS
30 GND2
29 GND2
28 IMODP
27 GND2
26 IMODN
25 VCC2
ADN2841
24 IBMON
23 IMMON
22 GND3
21 VCC3
20 ALS
19 FAIL
18 DEGRADE
17 CLKSEL
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