Analog Devices ADN2847 Datasheet

3V Dual-Loop 50 Mbps to 3.3 Gbps

a

FEATURES
50 Mbps to 3.3 Gbps Operation
Single 3.3 V Operation
Typical Rise/Fall Time 80 ps
Bias Current Range 2 mA to 100 mA
Modulation Current Range 5 mA to 80 mA
Monitor Photodiode Current 50 A to 1200 A
Dual MPD Functionality for DWDM
50 mA Supply Current at 3.3 V
Closed-Loop Control of Power and Extinction Ratio
Full Current Parameter Monitoring
Laser Fail and Laser Degrade Alarms
Automatic Laser Shutdown, ALS
Optional Clocked Data
Supports FEC Rates
48-Lead (7 mm  7 mm) LFCSP Package
32-Lead (5 mm  5 mm) LFCSP Package
Available in Die Form

Laser Diode Driver

ADN2847

APPLICATIONS
SONET OC-1/3/12/48
SDH STM-0/1/4/16
Fibre Channel
Gigabit Ethernet
DWDM Dual MPD Wavelength Control

GENERAL DESCRIPTION

The ADN2847 uses a unique control algorithm to control both
average power and extinction ratio of the laser diode, LD, after
initial factory setup. 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).

Optional dual MPD current monitoring is designed into the
ADN2847 specifically for DWDM wavelength control.

MPD

GND

GND

GND

V

CC

IMPD

IMPD2

PSET

ERSET

FUNCTIONAL BLOCK DIAGRAM

V

IBMON

IMMON

IMPDMON

IMPDMON2

ALS

FAIL

DEGRADE

I

MOD

CONTROL

I

BIAS

PAV CAPERCAP

GNDGND

CC

IMODN

CLKSEL

ADN2847

LBWSETIDTONE

CC

V

GND

IMODP

I

BIAS

ASET

GND

DATAP

DATAN

CLKP

CLKN

V

CC

LD

REV. 0

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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
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One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: [phone] www.analog.com
Fax: [phone] © 2003 Analog Devices, Inc. All rights reserved.

ADN2847

–SPECIFICATIONS

(VCC = 3.0 V to 3.6 V. All specifications T
otherwise noted.1 Typical values as specified at 25C.)

MIN

to T

, unless

MAX

Parameter Min Typ Max Unit Conditions/Comments

LASER BIAS (BIAS)

Output Current I

BIAS

Compliance Voltage 1.2 V

during ALS 0.1 mA

I

BIAS

ALS Response Time 5 µsI
CCBIAS Compliance Voltage 1.2 V

MODULATION CURRENT (IMODP, IMODN)

Output Current I

MOD

Compliance Voltage 1.5 V

during ALS 0.1 mA

I

MOD

Rise Time (See Figure 4 for Typical Distribution)
Fall Time (See Figure 5 for Typical Distribution)
Random Jitter
Pulsewidth Distortion

3

3

2 100 mA

CC

CC

2

V

V

580mA

CC

3

3

80 120 ps
80 120 ps

V

1 1.5 ps RMS
15 ps I

< 10% of nominal

BIAS

= 40 mA

MOD

MONITOR PD (MPD, MPD2)

Current 50 1200 µAAverage Current
Compliance Voltage 1.65 V

POWER SET INPUT (PSET)

Capacitance 80 pF
Monitor Photodiode Current into RPSET Resistor 50 1200 µAAverage Current
Voltage 1.1 1.2 1.3 V

EXTINCTION RATIO SET INPUT (ERSET)

Allowable Resistance Range 1.2 25 kΩ
Voltage 1.1 1.2 1.3 V

ALARM SET (ASET)

Allowable Resistance Range 1.2 25 kΩ
Voltage 1.1 1.2 1.3 V
Hysteresis 5 %

CONTROL LOOP Low Loop Bandwidth Selection

Time Constant 0.22 s LBWSET

2.25 s LBWSET = V

DATA INPUTS (DATAP, DATAN, CLKP, CLKN)

4

= GND

CC

V p-p (Single-Ended, Peak-to-Peak) 100 500 mV Data and Clock Inputs Are
Input Impedance (Single-Ended) 50 Ω AC-Coupled

5

(See Figure 1) 50 ps

t

SETUP

5

t

(See Figure 1) 100 ps

HOLD

LOGIC INPUTS (ALS, LBWSET, CLKSEL)

V

IH

V

IL

2.4 V

0.8 V

ALARM OUTPUTS (Internal 30 kΩ Pull-Up)

V

OH

V

OL

2.4 V

0.8 V

IDTONE

Compliance Voltage V





I

OUT




f

Ratio



I



IN

6

IN

0.01 1 MHz

–1.5 V

CC

2

User to Supply Current Sink
in the Range of 50 µA to 4 mA

IBMON, IMMON, IMPDMON, IMPDMON2

IBMON, IMMON Division Ratio 100 A/A
IMPDMON, IMPDMON2 1 A/A
IMPDMON to IMPDMON2 Matching 2 % I
Compliance Voltage 0 V

–1.2 V

CC

= 1200 µA

MPD

REV. 0–2–

ADN2847

Parameter Min Typ Max Unit Conditions/Comments

SUPPLY

7

I

CC

8

V

CC

NOTES

1

Temperature range: –40∞C to +85∞C.

2

The high speed performance for the die version of ADN2847 can be achieved when using the bonding diagram shown in Figure 3.

3

Measured into a 25 W load using a 11110000 pattern at 2.5 Gbps.

4

When the voltage on DATAP is greater than the voltage on DATAN, the modulation current flows in the IMODP pin.

5

Guaranteed by design and characterization. Not production tested.

6

IDTONE may cause eye distortion.

7

I

for power calculation on page 8 is the typical ICC given.

CCMIN

8

All VCC pins should be shorted together.

Specifications subject to change without notice.

3.0 3.3 3.6 V

50 mA I

BIAS

= I

MOD

= 0

ABSOLUTE MAXIMUM RATINGS

(TA = 25∞C, unless otherwise noted.)

1

VCC to GND . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.2 V

Digital Inputs (ALS, LBWSET, CLKSEL) . . –0.3 V to V

IMODN, IMODP . . . . . . . . . . . . . . . . . . . . . . . . . V

+ 0.3 V

CC

+ 1.2 V

CC

Operating Temperature Range

Industrial . . . . . . . . . . . . . . . . . . . . . . . . . . .–40∞C to +85∞C

Storage Temperature Range . . . . . . . . . . . . . –65∞C to +150∞C

Junction Temperature (T
48-Lead LFCSP Package

Power Dissipation

q

Thermal Impedance3 . . . . . . . . . . . . . . . . . . . . . 25∞C/W

JA

max) . . . . . . . . . . . . . . . . . . . 150∞C

J

2

. . . . . . . . . . . . . . . . (TJ max – TA)/qJA W

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

32-Lead LFCSP Package

Power Dissipation

q

Thermal Impedance3 . . . . . . . . . . . . . . . . . . . . . 32∞C/W

JA

2

. . . . . . . . . . . . . . . . (TJ max – TA)/qJA W

Lead Temperature (Soldering 10 sec) . . . . . . . . . . . . 300∞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

Power consumption formulae are provided on page 8.

3

q

is defined when part is soldered on a 4-layer board.

JA

ORDERING GUIDE

Temperature Package

Model Range Description

ADN2847ACP-32 –40∞C to +85∞C 32-Lead LFCSP
ADN2847ACP-48 –40∞C to +85∞C 48-Lead LFCSP
ADN2847ACP-32-RL –40∞C to +85∞C 32-Lead LFCSP
ADN2847ACP-32-RL7 –40∞C to +85∞C 32-Lead LFCSP
ADN2847ACP-48-RL –40∞C to +85∞C 48-Lead LFCSP

HOLD

t

H

DATAP/DATAN

CLKP

SETUP

t

S

Figure 1. Setup and Hold Time

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
ADN2847 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–

ADN2847

2280m

2620m

3 GNDCLKSEL

GND2

GND2

GND2

2

V

CC

IMODN

IMODN

GND2

IMODP
IMODP

GND2

GND2

I

BIAS

I

BIAS

CCBIAS

GND GND4

LBWSET

ASET

IBMON

ERSET

IMMON

PSET

GND

V

CC

IMPD

FAIL

ALS

IMPDMON2

Figure 2. Metallization Photograph

2280m

DEGRADEIDTONE

GNDGND3

GND

VCC4IMPD2IMPDMON

CLKN

CLKP

GND1

DATAP

DATAN

GND1

V

1

CC

GND

PAVCAP

ERCAP

DIE ROTATED 90 IN PACKAGE

1

BOTTOM

LEFT RIGHT

TOP

2620m

Figure 3. Bonding Diagram

DIE PAD COORDINATES*

Pad Number Pad Name x[m] Y[m]

1 TP1 (GND) –996 1026
2 LBWSET –996 853
3 ASET –996 679
4 ERSET –996 506
5 PSET –996 332

6 TP2 (GND) –996 159
7 IMPD –996 –15

8IMPDMON –996 506
9 IMPDMON2 –996 –361
10 IMPD2 –996 –534
11 GND4 –996 –724
12 V

4 –995 –964

CC

13 ERCAP –925 –1191
14 PAVCAP –777 –1191
15 TP3 (GND) –606 –1191
16 V

1 –389 –1191

CC

17 GND1 –200 –1191
18 DATAN –70 –1191
19 DATAP 83 –1191
20 GND1 263 –1191
21 CLKP 442 –1191
22 CLKN 596 –1191
23 TP4 (GND) 762 –1191
24 TP5 (GND) 996 –1109
25 TP6 (GND) 996 –935
26 CLKSEL 996 –762
27 DEGRADE 996 –589
28 FAIL 996 –415
29 ALS 996 –242

Pad Number Pad Name x[m] Y[m]

30 V

3 996 –19

CC

31 GND3 996 251
32 IMMON 996 441
33 IBMON 996 614
34 GND2 996 804
35 IDTONE 995 993
36 GND2 995 1133
37 GND2 867 1191
38 V

2 713 1191

CC

39 IMODN 500 1191
40 IMODN 396 1191
41 GND2 242 1191
42 IMODP 88 1191
43 IMODP –16 1191
44 GND2 –239 1191
45 GND2 –443 1191
46 I
47 I

BIAS

BIAS

–633 1191
–772 1191

48 CCBIAS –912 1191

*With the origin in the center of the die (see Figure 2).

REV. 0–4–