Analog Devices ADN2830 a Datasheet
Continuous Wave Laser
a
FEATURES
Bias Current Range 4 mA to 200 mA
Monitor Photodiode Current 50 A to 1200 A
Closed-Loop Control of Average Power
Laser FAIL and Laser DEGRADE Alarms
Automatic Laser Shutdown, ALS
Full Current Parameter Monitoring
5 V Operation
–40C to +85C Temperature Range
5 mm 5 mm 32-Lead LFCSP Package
APPLICATIONS
Fiber Optic Communication
Average Power Controller
ADN2830
GENERAL DESCRIPTION
The ADN2830 provides closed-loop control of the average
optical power of a continuous wave (CW) laser diode (LD)
after initial factory setup. The control loop adjusts the laser
IBIAS to maintain a constant back facet monitor photodiode
(MPD) current and thus a constant laser optical power. The
external PSET resistor is adjusted during factory setup to set
the desired optical power. R
is the MPD current corresponding to the desired optical power.
Programmable alarms are provided for laser fail (end of life)
and laser degrade (impending fail).
To provide monitoring of the MPD current, the MPD can be
connected to the IMPD pin. In this case, the MPD current is
mirrored to the IMPDMON pin to provide a monitor and
internally to the PSET pin to close the control loop.
By closing the feedback using IBMON rather than an MPD
connected to PSET, the device is configured to control a constant
current in the laser rather than a constant optical output power.
is set at 1.23/IAV, where I
PSET
AV
R
MPD
PSET
V
GND
CC
FUNCTIONAL BLOCK DIAGRAM
IBMON IMPDMON ALS FAI L DEGRADE
IMPD
GND
PSET
GND
PAV CAP
CONTROL
MODE
V
GND
CC
IBIAS
ASET
LD
GND
V
CC
R
ASET
REV. AREV. A
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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.
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Tel: 781/329-4700 www.analog.com
Fax: 781/326-8703 © 2003 Analog Devices, Inc. All rights reserved.
ADN2830–SPECIFICATIONS
(VCC = 5 V 10%. All specifications T
Typical values as specified at 25C.)
MIN
to T
, unless otherwise noted1.
MAX
Parameter Min Typ Max Unit Conditions/Comments
LASER BIAS (BIAS)
Output Current IBIAS 4 200 mA
Compliance Voltage 1.2
V
CC
V
IBIAS during ALS 40 µA
ALS Response Time 10 µs
MONITOR PD (IMPD)
Current 50 1200 µA
Input Voltage 1.6 V
POWER SET INPUT (PSET)
Capacitance 80 pF
Input Current 50 1200 µA
Voltage 1.15 1.23 1.35 V
ALARM SET (ASET)
Allowable Resistance Range 1.2 13 kΩ
Voltage 1.15 1.23 1.35 V
Hysteresis 5 %
LOGIC INPUTS (ALS, MODE)
V
IH
V
IL
2.4 V
0.8 V
ALARM OUTPUTS (Internal 30 kΩ Pull-Up)
V
OH
V
OL
2.4 V
0.4 V
IBMON IMPDMON
IBMON, Division Ratio 100 A/A
IMPDMON Division Ratio 1 A/A
Compliance Voltage 0 VCC – 1.2 V
SUPPLY
2
I
CC
V
CC
NOTES
1
Temperature range: –40°C to +85°C.
2
ICC for power calculation is the typical ICC given.
Specifications subject to change without notice.
4.5 5.0 5.5 V
25 mA IBIAS = 0
–2–
REV. A
ADN2830
ABSOLUTE MAXIMUM RATINGS
(TA = 25°C, unless otherwise noted.)
1
VCCto GND . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 V
Digital Inputs (ALS, Mode) . . . . . . . . .–0.3 V to V
+ 0.3 V
CC
Operating Temperature Range
Industrial . . . . . . . . . . . . . . . . . . . . . . . . . . –40°Cto+85°C
NOTES
1
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.
2
θJA is defined when the part is soldered onto a 4-layer board.
Storage Temperature Range . . . . . . . . . . –65°Cto+150°C
Junction Temperature (T
Max ) . . . . . . . . . . . . . . . . . 150°C
J
θJA Thermal Impedance2 . . . . . . . . . . . . . . . . . . . . 32°C/W
32-Lead LFCSP Package,
Power Dissipation . . . . . . . . . . . . . . (T
Max – TA)/θJAmW
J
Lead Temperature (Soldering 10 sec) . . . . . . . . . . . . . . 300°C
ORDERING GUIDE
Model Temperature Range Package Description
ADN2830ACP32 –40°C to +85°C 32-Lead LFCSP
ADN2830ACP32-REEL7 –40°C to +85°C 32-Lead LFCSP
ADN2830ACP32-REEL –40°C to +85°C 32-Lead LFCSP
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 ADN2830 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
REV. A
–3–
ADN2830
PIN CONFIGURATION
3
CC
24 IBMON
23 IBMON
22 GND3
21 V
20 ALS
19 FAIL
18 DEGRADE
17 MODE
25
2
V
CC
NC 26
GND2 27
IBIAS 28
GND2 29
GND2 30
IBIAS 31
NC 32
NC = NO CONNECT
ADN2830
TOP VIEW
PIN 1
INDICATOR
NC 3
GND 1
ASET 2
IMPD 5
PSET 4
PIN FUNCTION DESCRIPTIONS
Pin No. Mnemonic Function
1GND Supply Ground
2 ASET Alarm Current Threshold Set Pin
3NCNo Connect
4 PSET Average Optical Power Set Pin
5 IMPD Monitor Photodiode Input
6IMPDMON Mirrored Current from Monitor Photodiode—Current Source
7 GND4 Supply Ground
8V
4 Supply Voltage
CC
9 PAVCAP Average Power Loop Capacitor
10 PAVCAP Average Power Loop Capacitor
11 V
12 V
1 Supply Voltage
CC
5 Supply Voltage
CC
13 NC No Connect
14 GND1 Supply Ground
15 NC No Connect
16 NC No Connect
17 MODE Mode Select: Tied to ALS = Standalone, High = Parallel Current Booster
18 DEGRADE DEGRADE Alarm Output
19 FAIL FAIL Alarm Output
20 ALS Automatic Laser Shutdown
21 V
3 Supply Voltage
CC
22 GND3 Supply Ground
23 IBMON Bias Current Monitor Output—Current Source
24 IBMON Bias Current Monitor Output—Current Source
25 V
2 Supply Voltage
CC
26 NC No Connect
27 GND2 Supply Ground
28 IBIAS Laser Diode Bias Current
29 GND2 Supply Ground
30 GND2 Supply Ground
31 IBIAS Laser Diode Bias Current
32 NC No Connect
8
4
CC
V
GND4 7
IMPDMON 6
16 NC
15 NC
14 GND1
13 NC
12 V
5
CC
11
V
1
CC
10 PAVCAP
9 PAVCAP
–4–
REV. A
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