11.1 Gbps 3.3 V Low Noise,
High Gain TIA
ADN2821 Rev.PrJ
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. 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.One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A. Tel: https://www.wendangku.net/doc/6b16221804.html, Fax: 781.326.8703? 2003 Analog Devices, Inc. All rights reserved.
FEATURES
Bandwidth: 8 GHz min
Input noise current density: 12 pA/√Hz Optical sensitivity: ?19 dBm1
Differential transimpedance/linear range: ADN2821_2: 2.0 k?/0.20 mA p-p
ADN2821_5: 5.0 k?/0.08 mA p-p
ADN2821_10: 10.0 k?/0.04 mA p-p ADN2821_20: 20.0 k?/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 C LF = 0.5 nF ADN2821_10: 25 kHz with C LF = 1 nF
On-chip PD filter: R F = 200 ?, C F = 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.
1nF043
6
9
-
-
1
Figure 1. AD2821_5 Functional Block Diagram/
Typical Operating Circuit (TOC)
1 10–1
2 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 V PD
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 (L TEST , L OUT , L OUTB ~ 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 Conditions 1Min Typ Max Unit DYNAMIC PERFORMANCE
Bandwidth (BW)3
?3dB 8 9.5 GHz Total Input RMS Noise (I rms )2DC to 10 GHz 1.2 TBD μA Small Signal Transimpedance (T Z ) ADN2821_2, 100 MHz 1500 2000 2500 ? ADN2821_5, 100 MHz 3500 5000 6500 ? ADN2821_10, 100 MHz 6000 10000 15000 ? ADN2821_20, 100 MHz 12000 20000 30000 ? Transimpedance Ripple 2 50 MHz to 5 GHz ±1 dB
Group Delay Variation 2
50 MHz to 8 GHz ±10 ps Low Frequency Cutoff ADN2821_2, C LF = 200 pF 25 50 kHz ADN2821_5, C LF = 500 pF 25 50 kHz ADN2821_10, C LF = 1000 pF 25 50 kHz ADN2821_20, C LF = 1000 pF 25 50 kHz
Output Return Loss 2
DC to 8 Hz, differential ?12 ?10 dB Total p-p Jitter 2 I IN , p-p = 2.0 mA, 4 dB ER 5 ps
Input Overload Current 2 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, I IN , 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 I IN, AVE = 0.1 mA, 150 200 mW V CC = 3.3 V ± 5% Input Voltage 0.75 0.85 1.00 V Output Impedance Single-ended 45 50 55 ? POWMON Sensitivity I IN, AVE = 0 μA to 1 mA 0.75 1 1.25 V/mA POWMON Offset I IN, AVE = 0 μA 5 10 15 mV PD FILTER Resistance R F 180 200 220 ? PD FILTER Capacitance C F 66 pF
1 Min/Max V CC = 3.3 V ± 0.3 V, T AMBIENT = ?20°C to +85°C; Typ V CC = 3.3 V, T AMBIENT = 25°C.
2
Photodiode capacitance C D = 0.22 pF ± 0.04 pF. Photodiode resistance = 15 ?, C B = 100 pF. Bond inductance L IN = L FILTER = 0.3 nH ± 0.1 nH. L OUT = L OUTB = 0.5 nH ± 0.1 nH. Load impedance = 50 ? (each output, ac-coupled).
Preliminary Technical Data
Preliminary Technical Data ADN2821
Rev. PrJ | Page 4 of 13
ADN2821
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ABSOLUTE MAXIMUM RATINGS
Table 2.
Parameter Rating Supply Voltage (V CC 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
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 V CC to enable on-chip 200 ? × 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 ? termination (ac or dc termination). 7, 10 GND Ground (Output Return).
9, 11 OUTB Negative Output. Drives 50 ? 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
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 V PD CONNECTED THROUGH FILTER PIN
V 4.2mm 4mm
3mm
2mm
1mm
0mm
04369-0-004
Figure 4. 5-Pin TO-CAN with External Photodiode Supply V PD 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
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 210001log 1010?×+×+×=ER ER Z V I dBm y Sensitivit T S RMS
ρα
Table 7.
Description Value
ρ Photodiode responsivity (A/W) 0.85 A/W typical
I RMS 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 V S PA/CDR input sensitivity (V) 5 mV to 100 mV
Z T TIA transimpedance (V/A)
2 k? to 20 k? for ADN2821 family
Table 8. Optical Input Sensitivity (dBm)
ADN2821 Transimpedance (Z T )
PA/CDR Input Sensitivity (V S ) 2 k? 5 k? 10 k?
20 k?
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
()()ρ
1000log 1010
×=T LR
Z V dBm e LinearRang
Table 9.
Description Value ρ Photodiode responsivity (A/W) 0.85 A/W typical
V LR TIA output linear range (V) 400 mV typical for ADN2821 family Z T TIA transimpedance (V/A)
2 k? to 20 k? for ADN2821 family
Table 10. Optical Input Referred Linear Range (dBm)
ADN2821 Transimpedance (Z T ) 2 k? 5 k? 10 k?
20 k?
–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 T Z . Selecting the lowest ADN2821 T Z 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 T Z option. This low frequency cutoff can be tuned lower by adding an external capacitance to the CLF bond pad.
0pF
10kHz 100kHz 10nF
2.5pF 5pF 10pF 50pF
100pF
0.5nF
1nF
2.5nF 5nF
1MHz 500kHz 250kHz 50kHz 25kHz 2.5kHz 04369-0-006
Figure 6. Typical Low Frequency Cutoff vs. CLF Capacitance
TYPICAL OPERATING PERFORMANCE
ON-WAFER PROBE (L TEST , L OUT , L OUTB ~ 0.2 nH)
FREQUENCY RESPONSE
Test setup:
HP8722ES Network Analyzer
AC-coupled outputs terminated 50 Ω to GND Network analyzer port power = ?42 dBm (I TEST = 10 μA p-p, I AVE = 5 μA)
1
2
04369-0-007
Figure 7. Single-Ended s21 Plot of ADN2821_05k Measured at OUT
1
2
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 setup:
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 (I TEST = 100 μA p-p, I AVE = 50 μA)
04369-0-010
Figure 10. ADN2821_10k Differential Output (OUT-OUTB) with 231 10 Gbps PRBS Input at TEST (I TEST = 100 μA p-p, I AVE = 50 μA)
Preliminary Technical Data
ADN2821
Rev. PrJ | Page 13 of 13
OUTLINE DIMENSIONS
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
? 2003 Analog Devices, Inc. All rights reserved. Trademarks and
registered trademarks are the property of their respective owners. C04369-0-11/03(PrJ)
Preliminary Technical Data