ADN2821ACHIPS - Analog Devices

11.1 Gbps 3.3 V Low Noise,

High Gain TIA

ADN2821

Rev. PrJ

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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.

Specifications subject to change without notice. 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 owners.

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Tel: 781.329.4700 www.analog.com

FEATURES

Bandwidth: 8 GHz min

Input noise current density: 12 pA/√Hz

Optical sensitivity: −19 dBm1

Differential transimpedance/linear range:

ADN2821_2: 2.0 kΩ/0.20 mA p-p

ADN2821_5: 5.0 kΩ/0.08 mA p-p

ADN2821_10: 10.0 kΩ/0.04 mA p-p

ADN2821_20: 20.0 kΩ/0.02 mA p-p

Power dissipation: 150 mW

Input power monitor: 1 V/mA

Differential output swing: 400 mV p-p min

Input overload:

2.0 mA p-p min @ 4 dB ER

3.0 mA p-p min @ 10 dB ER

Low-F cutoff:

ADN2821_5: 25 kHz with CLF = 0.5 nF

ADN2821_10: 25 kHz with CLF = 1 nF

On-chip PD filter: RF = 200 Ω, CF = 66 pF

Die size: 0.90 mm × 1.10 mm

APPLICATIONS

10.7 Gbps optical modules

SONET/SDH OC-192/STM-64 and 10 GbE

Receivers, transceivers, transponders

GENERAL DESCRIPTION

The ADN2821 is a series of compact, high performance SiGe,

3.3 V transimpedance amplifiers (TIAs) optimized for small

form factor 10 Gbps metro-access and Ethernet PD-TIA

modules. The ADN2821 series features low input referred noise

current and a range of transimpedance gains, suitable for

driving a typical CDR or transceiver directly.

Eight GHz minimum BW enables up to 11.1 Gbps operation;

1.2 µA input referred noise current enables –19 dBm sensitivity;

2 mA p-p input overload current at 2.4 mA average input

current enables better than 4 dBm overload operation at a 4 dB

extinction ratio. For assembly in small form factor packages, the

ADN2821 series integrates a photodiode low-pass filter network

on-chip and features 25 kHz low frequency cutoff with a small

0.5 nF or 1.0 nF external capacitor. The POWMON output

signal proportional to average input current is available for

monitoring and alarm generation. The ADN2821 operates with

a 3.3 V ± 0.3 V power supply and is available in die form.

= 20dB

FILTER V

7, 10

9, 11

6, 8

CLF

1nF

POWMON

OUTB

OUT

GNDGND

FILTER 50Ω50Ω

500Ω

66pF 0.85V 10mA

hυ

3.3V

200Ω

ADN2821

04369-0-001

Figure 1. AD2821_5 Functional Block Diagram/

Typical Operating Circuit (TOC)

1 10–12 BER, 10 dB extinction ratio, 0.85 A/W PD responsivity.

Preliminary Technical Data

ADN2821

Rev. PrJ | Page 2 of 13

TABLE OF CONTENTS

Electrical Specifications................................................................... 3

Absolute Maximum Ratings............................................................ 5

ESD Caution.................................................................................. 5

Pad Configuration and Functional Descriptions ......................... 6

Assembly Recommendations.......................................................... 7

5-Pin TO-CAN with Common Photodiode Supply and

POWMON Output Pin................................................................ 7

5-Pin TO-CAN with External Photodiode Supply VPD

Connected through Filter Pin..................................................... 8

Butterfly Package with Common Photodiode Supply and

POWMON Output Pin................................................................ 9

Transimpedance Selection Guidelines......................................... 10

Optical Sensitivity vs. ADN2821 Transimpedance and

LA/CDR Input Sensitivity ......................................................... 10

Input Referred Linear Range vs. ADN2821 TransImpedance

....................................................................................................... 10

IN/FILTER — OUT/OUTB Mutual Inductance Feedback vs.

ADN2821 TransImpedance ...................................................... 10

Low Frequency Cutoff ................................................................... 11

Typical Operating Performance ................................................... 11

On-Wafer Probe (LTEST, LOUT, LOUTB ~ 0.2 nH) ........................ 11

Frequency Response .................................................................. 11

10 Gbps Eye Diagrams................................................................... 12

Outline Dimensions....................................................................... 13

Ordering Guide............................................................................... 13

REVISION HISTORY

Revision PrJ

Preliminary Technical Data

ADN2821

Rev. PrJ | Page 3 of 13

ELECTRICAL SPECIFICATIONS

Table 1.

Parameter Conditions1Min Typ Max Unit

DYNAMIC PERFORMANCE

Bandwidth (BW)3−3dB 8 9.5 GHz

Total Input RMS Noise (Irms)2DC to 10 GHz 1.2 TBD μA

Small Signal Transimpedance (TZ) ADN2821_2, 100 MHz 1500 2000 2500 Ω

ADN2821_5, 100 MHz 3500 5000 6500 Ω

ADN2821_10, 100 MHz 6000 10000 15000 Ω

ADN2821_20, 100 MHz 12000 20000 30000 Ω

Transimpedance Ripple2 50 MHz to 5 GHz ±1 dB

Group Delay Variation2 50 MHz to 8 GHz ±10 ps

Low Frequency Cutoff ADN2821_2, CLF = 200 pF 25 50 kHz

ADN2821_5, CLF = 500 pF 25 50 kHz

ADN2821_10, CLF = 1000 pF 25 50 kHz

ADN2821_20, CLF = 1000 pF 25 50 kHz

Output Return Loss2 DC to 8 Hz, differential −12 −10 dB

Total p-p Jitter2 I

IN, p-p = 2.0 mA, 4 dB ER 5 ps

Input Overload Current2 p-p, 10−12 BER, 4 dB ER 2.0 mA

p-p, 10−12 BER, 10 dB ER 3.0 mA

Maximum Output Swing p-p diff, IIN, p-p =2.5 mA 400 520 650 mV

Linear Output Range p-p, <1 dB gain compression 400 mV

Power Supply Rejection Ratio TBD TBD dB

DC PERFORMANCE

Power Dissipation IIN, AVE = 0.1 mA, 150 200 mW

CC = 3.3 V ± 5%

Input Voltage 0.75 0.85 1.00 V

Output Impedance Single-ended 45 50 55 Ω

POWMON Sensitivity IIN, AVE = 0 µA to 1 mA 0.75 1 1.25 V/mA

POWMON Offset IIN, AVE = 0 µA 5 10 15 mV

PD FILTER Resistance RF180 200 220 Ω

PD FILTER Capacitance CF 66 pF

1 Min/Max VCC = 3.3 V ± 0.3 V, TAMBIENT = −20°C to +85°C; Typ VCC = 3.3 V, TAMBIENT = 25°C.

2 Photodiode capacitance CD = 0.22 pF ± 0.04 pF. Photodiode resistance = 15 Ω, CB = 100 pF. Bond inductance LIN = LFILTER = 0.3 nH ± 0.1 nH. LOUT = LOUTB = 0.5 nH ± 0.1 nH.

Load impedance = 50 Ω (each output, ac-coupled).

Preliminary Technical Data

ADN2821

Rev. PrJ | Page 4 of 13

Preliminary Technical Data

ADN2821

Rev. PrJ | Page 5 of 13

ABSOLUTE MAXIMUM RATINGS

Table 2.

Parameter Rating

Supply Voltage (VCC to GND) 5.2 V

Output Short Circuit Duration Indefinite

Maximum Input Current 5 mA

Storage Temperature Range −65°C to +125°C

Operating Ambient Temperature Range −20°C to +85°C

Maximum Junction Temperature 150°C

Die Attach Temperature (<30 seconds) 420°C

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 condition s above those indicated in the operational

section of this specification is not implied. Exposure to absolute

maximum rating conditions for extended periods may affect

device reliability.

ESD 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 this product 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.

Preliminary Technical Data

ADN2821

Rev. PrJ | Page 6 of 13

PAD CONFIGURATION AND FUNCTIONAL DESCRIPTIONS

0,0

123

10 9 8 7

TEST GND

VCCFILTER

FILTER

POWMON

VCC

OUT

GND OUTB GND

OUTB

CLF

GND

OUT

04369-0-002

Figure 2. Pad Layout

Table 3. Pad Descriptions

No. Pad Function

P1 GND GND Probe Pad. Leave floating.

P2 TEST Test Probe Pad. Leave floating.

1 FILTER Filter Output. Bond directly to PD cathode.

2 IN Current Input. Bond directly to PD anode.

3 GND Ground (input return).

4 VCCFILTER Filter Supply. Connect to VCC to enable on-chip 200 Ω × 66 pF filter.

5 VCC 3.3 V Positive Supply. Recommended bypass to GND is 1000 pF RF capacitor.

6, 8 OUT Positive Output. Drives 50 Ω termination (ac or dc termination).

7, 10 GND Ground (Output Return).

9, 11 OUTB Negative Output. Drives 50 Ω termination (ac or dc termination).

12 CLF Low Frequency Setpoint. Connect with 1 nF capacitance to GND for <50 kHz.

13 POWMON Input Power Monitor Output.

Preliminary Technical Data

ADN2821

Rev. PrJ | Page 7 of 13

ASSEMBLY RECOMMENDATIONS

5-PIN TO-CAN WITH COMMON PHOTODIODE SUPPLY AND POWMON OUTPUT PIN

POWMON

OUTB

OUT

TIA

Clf

4.2mm

4mm

3mm

2mm

1mm

0mm

04369-0-003

Figure 3. 5-Pin TO-CAN with Common Photodiode Supply and POWMON Output Pin Assembly Drawing

Table 4. Bill of Materials

Qty. Description Source

PD 1 Vendor Specific (0.5 mm × 0.5 mm) 10 Gbps Photodiode

TIA 1 AD2821_X (0.87 mm × 1.06 mm) Analog Devices SiGe 10 Gbps Transimpedance Amplifier

Cb 1 D20BV201J5PX (0.5 mm × 0.5 mm) DiLabs 100 pF RF Single-Layer Capacitor

Clf 1 GM250X7R10216 (0.5 mm × 0.5 mm) muRata 1000 pF Ceramic Single-Layer Capacitor

Minimize all GND bond wire lengths.

Double bond to wide GND pads and OUT, OUTB pads where possible.

Minimize IN, FILTER, OUT, and OUTB bond wire lengths.

Maintain symmetry in length and orientation between IN and FILTER bond wires.

Maintain symmetry in length and orientation between OUT and OUTB bond wires.

Double bond OUT, OUTB wires perpendicular to IN, FILTER.

Maintain symmetry between IN/FILTER and OUT/OUTB bond wires.

Preliminary Technical Data

ADN2821

Rev. PrJ | Page 8 of 13

5-PIN TO-CAN WITH EXTERNAL PHOTODIODE SUPPLY VPD CONNECTED THROUGH FILTER PIN

FILTER

OUTB

OUT

TIA

Clf

4.2mm

4mm

3mm

2mm

1mm

0mm

04369-0-004

Figure 4. 5-Pin TO-CAN with External Photodiode Supply VPD Connected through FILTER Pin Assembly Drawing

Table 5. Bill of Materials

Qty. Description Source

PD 1 Vendor Specific (0.5 mm × 0.5 mm) 10 Gbps Photodiode

TIA 1 ADN2821_X (0.9 mm × 1.1 mm) Analog Devices SiGe 10 Gbps Transimpedance Amplifier

Cb 1 D20BV201J5PX (0.5 mm × 0.5 mm) DiLabs 100 pF RF Single-Layer Capacitor

Clf 1 GM250X7R10216 (0.5 mm × 0.5 mm) muRata 1000 pF Ceramic Capacitor

Minimize all GND bond wire lengths.

Double bond to wide GND pads and OUT, OUTB pads where possible.

Minimize IN, FILTER, OUT, and OUTB bond wire lengths.

Maintain symmetry in length and orientation between IN and FILTER bond wires.

Maintain symmetry in length and orientation between OUT and OUTB bond wires.

Double bond OUT, OUTB wires perpendicular to IN, FILTER.

Maintain symmetry between IN/FILTER and OUT/OUTB bond wires.

Preliminary Technical Data

ADN2821

Rev. PrJ | Page 9 of 13

BUTTERFLY PACKAGE WITH COMMON PHOTODIODE SUPPLY AND POWMON OUTPUT PIN

5.0mm

7.5mm

2.5mm

0mm

Clf

OUT

OUTB

POWMON

04369-0-005

Figure 5. Butterfly Package with Common Photodiode Supply and POWMON Output Pin Assembly Drawing

Table 6. Bill of Materials

Qty. Description Source

PD 1 Vendor Specific (0.5 mm × 0.5 mm) 10 Gbps Photodiode

TIA 1 ADN2821_X (0.9 mm × 1.1 mm) Analog Devices SiGe 10 Gbps Transimpedance Amplifier

Cb 1 D20BV201J5PX (0.5 mm × 0.5 mm) DiLabs 100 pF RF Single-Layer Capacitor

Clf 1 GM250X7R10216 (0.5 mm × 0.5 mm) muRata 1000 pF Ceramic Capacitor

Minimize all GND bond wire lengths.

Double bond to wide GND pads where possible.

Minimize IN, FILTER, OUT, and OUTB bond wire lengths.

Maintain symmetry in length and orientation between IN and FILTER bond wires.

Maintain symmetry in length and orientation between OUT and OUTB bond wire.

Maintain symmetry between IN/FILTER and OUT/OUTB bond wires.

Preliminary Technical Data

ADN2821

Rev. PrJ | Page 10 of 13

TRANSIMPEDANCE SELECTION GUIDELINES

OPTICAL SENSITIVITY VS. ADN2821 TRANSIMPEDANCE AND LA/CDR INPUT SENSITIVITY

() ()(

()

)

1 2 10001

log10 10 −

×+×+×

=ER ERZVI

dBmySensitivit TSRMS

Table 7.

Description Value

ρ Photodiode responsivity (A/W) 0.85 A/W typical

IRMS TIA input referred noise (A) 1.2 µA typical for ADN2821 family

α BER Scaling Factor 14.1 for 10–12 BER

ER Extinction ratio 10 dB typical

VSPA/CDR input sensitivity (V) 5 mV to 100 mV

ZTTIA transimpedance (V/A) 2 kΩ to 20 kΩ for ADN2821 family

Table 8. Optical Input Sensitivity (dBm)

ADN2821 Transimpedance (ZT)

PA/CDR Input Sensitivity (VS) 2 kΩ 5 kΩ 10 kΩ 20 kΩ

100 mV –13.2 –15.8 –17.1 –18.0

50 mV –15.2 –17.1 –18.0 –18.6

25 mV –16.8 –18.0 –18.6 –18.8

10 mV –18.0 –18.7 –18.9 –19.0

5 mV –18.6 –18.9 –19.0 –19.1

INPUT REFERRED LINEAR RANGE VS. ADN2821 TRANSIMPEDANCE

()

1000

log10 10 ×

=TLR ZV

dBmeLinearRang

Table 9.

Description Value

ρ Photodiode responsivity (A/W) 0.85 A/W typical

VLR TIA output linear range (V) 400 mV typical for ADN2821 family

ZTTIA transimpedance (V/A) 2 kΩ to 20 kΩ for ADN2821 family

Table 10. Optical Input Referred Linear Range (dBm)

ADN2821 Transimpedance (ZT)

2 kΩ 5 kΩ 10 kΩ 20 kΩ

–6.3 –10.3 –13.3 –16.3

IN/FILTER — OUT/OUTB MUTUAL INDUCTANCE

FEEDBACK VS. ADN2821 TRANSIMPEDANCE

Mutual inductance feedback from OUT/OUTB bond wires to

IN/FILTER bond wires is proportional to ADN2821 TZ.

Selecting the lowest ADN2821 TZ required to achieve the

desired sensitivity will reduce this feedback gain and the

possibility of associated positive feedback frequency peaking

and time domain ringing. This mutual inductance feedback

path will be suppressed by ensuring short and symmetric

IN/FILTER/OUT/OUTB bond wires to reduce their absolute

and differential mutual inductances (See assembly

recommendations, Figures 3-5).

Preliminary Technical Data

ADN2821

Rev. PrJ | Page 11 of 13

LOW FREQUENCY CUTOFF

Digital encoding methods may generate long strings of 1s or 0s,

requiring the transimpedance amplifier pass band to extend to

1 MHz or below. The ADN2821 includes on-chip low frequency

filter circuitry to provide nominal low frequency cutoff in the

100 kHz to 500 kHz range with no external set capacitance,

depending on the TZ option. This low frequency cutoff can be

tuned lower by adding an external capacitance to the CLF bond

pad.

0pF

1kHz

10kHz

100kHz

10nF

2.5pF5pF10pF 50pF

100pF 0.5nF1nF 2.5nF5nF

1MHz

500kHz

250kHz

50kHz

25kHz

5kHz

2.5kHz

ADN2821_02k

ADN2821_05k

ADN2821_10k, 20k

04369-0-006

Figure 6. Typical Low Frequency Cutoff vs. CLF Capacitance

TYPICAL OPERATING PERFORMANCE

ON-WAFER PROBE (LTEST, LOUT, LOUTB ~ 0.2 nH)

FREQUENCY RESPONSE

Test s etup:

HP8722ES Network Analyzer

AC-coupled outputs terminated 50 Ω to GND

Network analyzer port power = −42 dBm

(ITEST = 10 µA p-p, IAV E = 5 µA)

04369-0-007

Figure 7. Single-Ended s21 Plot of ADN2821_05k Measured at OUT

04369-0-008

Figure 8. Single-Ended s21 Plot of ADN2821_10k Measured at OUT

Preliminary Technical Data

ADN2821

Rev. PrJ | Page 12 of 13

10 Gbps EYE DIAGRAMS

Test s etup:

Agilent Infiniium DCA 86100B oscilloscope

Advantest D3186 PRBS generator

AC-coupled outputs terminated 50 Ω to GND

04369-0-009

Figure 9. ADN2821_5k Differential Output (OUT-OUTB) with 231

10 Gbps PRBS Input at TEST (ITEST = 100 µA p-p, IAVE = 50 µA)

04369-0-010

Figure 10. ADN2821_10k Differential Output (OUT-OUTB) with 231

10 Gbps PRBS Input at TEST (ITEST = 100 µA p-p, IAVE = 50 µA)

Preliminary Technical Data

ADN2821

Rev. PrJ | Page 13 of 13

OUTLINE DIMENSIONS

ADN2821

SINGLE PAD SIZE: 0.076 mm x 0.076mm

(pads 2, 4, 5, 8, 9, 12, 13)

DOUBLE PAD SIZE: 0.144 mm x 0.076mm

(pads 1, 3, 6, 7, 10, 11)

1.10 mm

0.30 mm

123

10987

TEST

GND

0.90 mm

Figure 11. Die Form

ORDERING GUIDE

Model Temperature Range Package Description

ADN2821ACHIPS-02K −25°C to +85°C Die Form

ADN2821ACHIPS-05K −25°C to +85°C Die Form

ADN2821ACHIPS-10K −25°C to +85°C Die Form

ADN2821ACHIPS-20K −25°C to +85°C Die Form

registered trademarks are the property of their respective owners.

C04369-0-11/03(PrJ)

Preliminary Technical Data