ANALOG DEVICES ADN2830 Service Manual

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
–40C to +85C 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 FAIL DEGRADE

IMPD

GND

PSET

GND

PAVCAP

CONTROL

MODE

V

GND

CC

IBIAS

ASET

LD

GND

V

CC

R

ASET

B

REV.REV.

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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
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Tel: [phone] www.analog.com

781/461-3113

Fax: © Analog Devices, Inc. All rights reserved.

2012

ADN2830–SPECIFICATIONS

(VCC = 5 V  10%. All specifications T
Typical values as specified at 25C.)

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.

B

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°C to +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°C to +150°C

Junction Temperature (T

Thermal Impedance2 . . . . . . . . . . . . . . . . . . . . 32°C/W

θ

JA

Max ) . . . . . . . . . . . . . . . . . 150°C

J

32-Lead LFCSP Package,

Power Dissipation . . . . . . . . . . . . . . (T

Max – TA)/θJAmW

J

Lead Temperature (Soldering 10 sec) . . . . . . . . . . . . . . 300°C

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.

B

–3–