107791469 - Agere Systems, Inc.

Preliminary Data Sheet

January 1998

LG1628AXA SONET/SDH 2.488 Gbits/s

Transimpedance Ampliﬁer

Features

■

High data rate: 2.5 Gbits/s

■

High gain: 5.8 k

Ω

transimpedance

■

Complementary 50

Ω

outputs

■

Low noise

■

Ultrawide dynamic range

■

Single –5.2 V ECL power supply

Applications

■

SONET/SDH receivers

■

SONET/SDH test equipment

■

Digital video transmission

Functional Description

The Lucent Technologies Microelectronics Group

LG1628AXA is a hybrid integrated circuit that com-

bines the Lucent LG1628A gallium arsenide (GaAs)

transimpedance ampliﬁer chip with an external Si

dual operational ampliﬁer and necessary ﬁltering to

achieve an ultrawide dynamic range ampliﬁer. The

LG1628AXA is capable of handling input currents

from 3

avg

to 4 mA

avg

(patent pending). Ampliﬁer

operation is from a single –5.2 V power supply. The

targeted transmission system is SONET OC-48 and

SDH STM-16.

A complete receiver/regenerator can be constructed

with an LG1628AXA followed by an LG1605 limiting

ampliﬁer and LG1600 clock and data regenerator.

Figure 1 shows the block diagram of the LG1628AXA

transimpedance amplifier. The amplifier consists of a

4.2 k

Ω

differential transimpedance stage followed by

a limiting buffer that provides complementary 50

Ω

outputs.

5-5329(F)

Figure 1. LG1628AXA Functional Diagram

GND

VSS

ZEFF

50 Ω

LIMITING

BUFFER

OUT+

OUT–

OVERLOAD CONTROL

IN–

IN+

LG1628AXA SONET/SDH 2.488 Gbits/s Preliminary Data Sheet

Transimpedance Ampliﬁer January 1998

2Lucent Technologies Inc.

Die Pad Conﬁguration

The die pad conﬁguration is shown in Figure 2.

5-5336(F)r.2

Figure 2. Die Pad Conﬁguration

VSS2

GND2

OUT–

OUT+

GND2

VSS1

OP2+B

OP2+A

OP2–

OP1+

OP1–

OP1OUT

OP2OUT

BYPASS

IN+

GND1

IN–

GND1

GND2

DNC

4 5 6 7 8 9 10 11 11

17181819191919202122

OUTSIDE DIE DIMENSIONS:

1.62 mm2 x 1.62 mm2

PAD SIZE:

100 µm2 x 100 µm2

(EXCEPT PAD #23, 100 µm2 x 150 µm2)

PAD SEPARATION:

50 µm

Preliminary Data Sheet LG1628AXA SONET/SDH 2.488 Gbits/s

January 1998 Transimpedance Ampliﬁer

Lucent Technologies Inc.

Die Pad Conﬁguration

(continued)

The pad descriptions for the LG1628AXA are given in Table 1.

Table 1. Pad Descriptions

Pad Symbol Description

1 IN+ Ampliﬁer input; connect to detector anode, current should enter this node.

2, 19, 23 GND

Ground.

3 BYPASS Connections between these nodes and an external dual op amp form the over-

load control circuitry. See the test circuit in Figure 4 for wiring details.

To operate the ampliﬁer without overload control connect OP2

OUT

to V

OP1

OUT

to GND, and leave BYPASS and the remaining op amp connections

open (Figure 5).

4 OP2

OUT

5 OP1

OUT

6 OP1–

7 OP1+

8 OP2–

9 OP2+A

10 OP2+B

11 V

SS1

Supply voltage; –5.2 Vdc nominal.

12 V

SS2

Supply voltage; –5.2 Vdc nominal.

13, 16, 18 GND

Ground.

14 OUT– Inverted data output (produces low-level output for current entering IN+).

15 OUT+ Noninverted data output (produces high-level output for current entering IN+).

17 BG Connection for external –2.5 Vdc voltage reference (typically use an Si band-

gap).

20, 21, 22 DNC Do not connect; internal test point or reserved for future use.

24 IN– Inverting input; must provide ac bypass to ground when using overload control.

LG1628AXA SONET/SDH 2.488 Gbits/s Preliminary Data Sheet

Transimpedance Ampliﬁer January 1998

4Lucent Technologies Inc.

Typical Connections and Padout of the Hybrid Integrated Circuit

5-5336(F).r3

* OUT– is delayed approximately 25 ps with respect to OUT+ due to the longer microstrip line associated with OUT–. An extra delay should be

added to OUT+ before connecting to the next circuit.

Figure 3. Typical Connections to the HIC (See Figure 4 for a Schematic of the Circuitry on the HIC.)

Table 2. HIC Pad Functional Description

Symbol Description

IN+ Ampliﬁer input; connect to detector anode, current should enter this node.

APD+ RF bypassed connection for the cathode of the APD.

DET

APD power supply connection.

Supply voltage; –5.2 Vdc nominal.

GND Ground (back of HIC is also ground).

Thermistor Negative temperature coefﬁcient thermistor for APD gain control.

OUT+ Noninverted data output (produces high-level output for current entering IN+).

OUT– Inverted data output (produces low-level output for current entering IN+).

50 Ω

OUT–*

APD

IN+

APD+

50 Ω

OUT+*

+VDET VSS

60x30 7

125x60

60x30

109

60x30

60X30

120X100 20

60X30

GND THERMISTOR

Preliminary Data Sheet LG1628AXA SONET/SDH 2.488 Gbits/s

January 1998 Transimpedance Ampliﬁer

Lucent Technologies Inc.

Absolute Maximum Ratings

Stresses in excess of the absolute maximum ratings can cause permanent or latent damage to the device. These

are absolute stress ratings only. Functional operation of the device is not implied at these or any other conditions in

excess of those given in the operational sections of the data sheet. Exposure to absolute maximum ratings for

extended periods can adversely affect device reliability.

Table 3. Absolute Maximum Ratings

Recommended Operating Conditions

Table 4. Recommended Operating Conditions

Handling Precautions

Although protection circuitry has been designed into this de vice, proper precautions should be taken to av oid e xpo-

sure to electrostatic discharge (ESD) during handling and mounting. Lucent Technologies Microelectronics Group

employs a human-body model (HBM) and a charged-device model (CDM) for ESD-susceptibility testing and pro-

tection design evaluation. No industry-wide standard has been adopted for the CDM. However, a standard HBM

(resistance = 1500

Ω

, capacitance = 100 pF) is widely used and, therefore , can be used for comparison purposes.

The HBM ESD threshold presented here was obtained by using these circuit parameters.

Table 5. ESD Threshold

Parameter Min Max Unit

Supply Voltage Range (V

) –7 0.5 V

Power Dissipation — 1 W

Voltage (all pins) 0.5 V

Storage Temperature Range –40 125

Operating Temperature Range 0 100

Parameter Symbol Min Max Unit

Ambient Temperature T

085

Power Supply V

–4.7 –5.7 V

HBM ESD Threshold

Device Voltage

LG1628AXA >500 V

LG1628AXA SONET/SDH 2.488 Gbits/s Preliminary Data Sheet

Transimpedance Ampliﬁer January 1998

6Lucent Technologies Inc.

Electrical Characteristics

= 25

C, V

= –5.2 V, C

DETECTOR

= 0.5 pF, R

LOAD

= 50

Ω

, unless otherwise indicated.

Parameter Symbol Min Typ Max Unit

Power Supply Voltage V

–5.7 –5.2 –4.7 V

Power Supply Current I

— 140 — mA

Effective Small-signal Transimpedance

(Single-ended input to either OUT+ or

OUT– each driving a 50

Ω

load, differ-

ential gain is twice this value.)

— 5.8 — k

Ω

Small-signal Bandwidth BW 1.5 1.6 — GHz

Transimpedance Peaking T

—0 1dB

Output Return Loss S

10 15 — dB

Input Noise Current

(100 kHz—2.5 GHz) I

NOISE

— 300 350 nArms

Operating Temperature Range T

0—85

Preliminary Data Sheet LG1628AXA SONET/SDH 2.488 Gbits/s

January 1998 Transimpedance Ampliﬁer

Lucent Technologies Inc.

Test Circuit with Overload Control

5-5335(F)r.1

1. Operational ampliﬁers OP1 and OP2 should hav e the following characteristics (suggested op amps are the LMC6082IM or OP291GS, both

are available as dual op amps in an 8-pin SOIC package):

a.Single 5 V supply operation. d.High-level output to within 2 V of the positive rail.

b.Maximum input offset voltage of 1 mV. e.Gain bandwidth product

≥

1.8 MHz.

c.Low-level output includes negative rail. f. Large signal voltage gain

≥

100 V/mV.

2. An on-chip 75 k

Ω

resistor to the negative supply is provided for biasing the voltage reference. Approximately 100

A of current will be

drawn. (Suggested bandgap reference is the LM4040BIM–2.5, available in an SOT-23 package.)

3. Node IN+ is nominally at –3.3 Vdc. APD supply voltage +V

det

should be adjusted appropriately.

4. R

LIN may be necessary to achieve stability depending on the physical arrangement of the APD and its associated electrical parasitics

(series inductance and other resonances). The ampliﬁer will be stable with a 0.5 pF detector capacitance in series with a 0.5 nH inductor,

but packaged detectors usually do not behave so ideally at frequencies above a few gigahertz. A parallel RL network consisting of a 200 Ω

resistor and a 6 nH inductor is provided on HIC and may be optionally used with a slight noise penalty. Good isolation from output to input

is also essential for ampliﬁer stability.

5. A low-pass ﬁlter is provided on the LG1628AXA HIC to reduce higher-frequency noise contributions (Butterworth N = 2, Zo = 50 and fc =

4.25 GHz, LOUT = 2.65 nH, COUT = 0.5 pF).

Figure 4. Optical Receiver with Overload Control

OP11–

OP21–

345678910 1112

0.047 µF

0.047 µF300 pF

5.2 V

+VDET

0.1 µF10 Ω

100 pF

Vss

GND1

VSS2

ZEFF

50 Ω

LIMITING

BUFFER

OUT+

OUT–

IN–

IN+

BYPASS

OP2OUT

OP1OUT

OP1–

OP1+

OP2–

OP2+A

OP2+B

VSS1

GND2

OVERLOAD CONTROL

114

1819

0.02 µF300 pF 0.047 µF

0.047 µF50 Ω

50 Ω

APD

27 kΩ

VSS1

BG 17

2.5 V

BANDGAP2

~100 µA

10 Ω

100 pF

0.033 µF

50 Ω

1 kΩ

APD+

(SEE NOTE 3 FOR BIAS CONDITIONS)

RIN

LIN

LOUT

COUT

(LPF, SEE NOTE 5)

100 V CAPS

(SEE NOTE 4)

LG1628AXA SONET/SDH 2.488 Gbits/s Preliminary Data Sheet

Transimpedance Ampliﬁer January 1998

8Lucent Technologies Inc.

Test Circuit with Overload Control Disabled

5-5334(F)r.3

Note: Notes 2, 3, 4, and 5 from the previous page (Figure 4) apply to this drawing.

Figure 5. Optical Receiver with Overload Control Disabled

+5.2 V

0.1 µF

10 Ω

100 pF

VSS

NC NC NC NC NC NC

GND1

VSS2

ZEFF

50 Ω

LIMITING

BUFFER

OUT+

OUT–

IN–

IN+

BYPASS

OP2OUT

OP1OUT

OP1–

OP1+

OP2–

OP2+A

OP2+B

VSS1

GND2

OVERLOAD CONTROL

345678910 1112

1819

0.02 µF300 pF 0.047 µF

0.047 µF50 Ω

50 Ω

APD

27 kΩ

VSS1

BG 17

2.5 V

BANDGAP

~100 µA

10 Ω

100 pF

0.033 µF

50 Ω

1 kΩ

APD+

RIN

LIN

LOUT

COUT

100 V CAPS

Preliminary Data Sheet LG1628AXA SONET/SDH 2.488 Gbits/s

January 1998 Transimpedance Ampliﬁer

9Lucent Technologies Inc.

Characteristic Curves (at TA = 25 °C, VSS = –5.2 V, CDETECTOR = 0.0 pF, 0.5 pF, 1.0 pF, RLOAD = 50 Ω)

5-5330(F)r.1, 5-5331(F).ar2, 5-5332(F)r.2, 5-5333(F)r.2

1. >25 dB dynamic range requires an external Si dual operational ampliﬁer. The detector polarity is such that current enters the LG1628A (i.e.,

the detector anode is connected to the LG1628A).

Figure 6. Characteristic Curves as Measured on the LG1628AXA Hybrid Integrated Circuit

A. Small-Signal Transimpedance B. Overload Characteristics1

C. Input Spectral Noise Density D. Total Input Noise Current

00.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0

FREQUENCY (GHz)

0.0 pF

1.0 pF

0.5 pF

SITOT (pA/ Hz)

400

350

300

250

150

100

00.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0

FREQUENCY (GHz)

ITOT (nArms)

0.0 pF

1.0 pF

0.5 pF

200

500 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0

FREQUENCY (GHz)

TRANSIMPEDANCE (dBΩ)

1.0 pF

0.5 pF

0.0 pF

600

100

0.001 0.01 0.1 1

APD CURRENT (mAavg)

OUTPUT VOLTAGE (mVp-p)

200

300

400

500

LG1628AXA SONET/SDH 2.488 Gbits/s Preliminary Data Sheet

Transimpedance Ampliﬁer January 1998

10 Lucent Technologies Inc.

Dimensional Drawing of the Hybrid Integrated Circuit (HIC)

Dimensions are in inches. Ceramic thickness is 0.025 inches.

5-5336(F).ar3

Figure 7. HIC Dimensions and Location of Bonding Pads

Ordering Information

* Second output on BXA is terminated through to ground 50 Ω on hybrid.

Device Code Package Temperature Comcode

(Ordering Number)

LG1628AXA Hybrid Integrated Circuit

Differential Output 0 °C to 85 °C 107791469

LG1628BXA* Hybrid Integrated Circuit

Single-ended Output 0 °C to 85 °C 108052085

60x30 7

125x60

60x30

109

60x30

60X30

120X100 20

60X30

0.327

0.224

0.005

0.550

0.358

0.141

0.018 0.238

0.318

0.380

0.525

0.019

0.005

0.035

Preliminary Data Sheet LG1628AXA SONET/SDH 2.488 Gbits/s

January 1998 Transimpedance Ampliﬁer

11Lucent Technologies Inc.

Notes

LG1628AXA SONET/SDH 2.488 Gbits/s Preliminary Data Sheet

Interactive Terminal Transmission Convergence January 1998

Lucent Technologies Inc. reserves the right to make changes to the product(s) or information contained herein without notice. No liability is assumed as a result of their use or application. No

rights under any patent accompany the sale of any such product(s) or information.

Printed in U.S.A.

January 1998

DS97-156FCE

For additional information, contact your Microelectronics Group Account Manager or the following:

INTERNET: http://www.lucent.com/micro

E-MAIL: docmaster@micro.lucent.com

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1-800-372-2447, FAX 610-712-4106 (In CANADA: 1-800-553-2448, FAX 610-712-4106)

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Tel. (65) 778 8833, FAX (65) 777 7495

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Tel. (81) 3 5421 1600, FAX (81) 3 5421 1700

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