Data Sheet
February 1999
LG1605DXB Limiting Amplifier
Features
■28 dB gain, 34 dB differential
■Large dynamic range: >60 dB
■Wideband response: 8 kHz to 3 GHz
■Extremely low ±4 ps dela y skew across input range
■Complementary 50 Ω I/Os
■Surface-mount package
■Stan dard ECL suppl y (4 00 mW)
Applications
■Data/clock main amplifier SONET/SDH OC-48/
STM-16 transmission systems, DWDM systems
■Digi tal video transmission
■Interface between 1319 receiver and LG1600
clock and data regenerator
■High-speed comparator
Functional Description
The LG1605DXB is a GaAs wideband limiting ampli-
fier with differential inputs and outputs that provides
28 dB of gain (34 dB differential) and 3 GHz of band-
width in a 50 Ω environment (Figure 1 shows the
block diagram). At low input levels, below 10 mV to
20 mV, the circuit behaves as a linear amplifier. At
higher lev els, the device goes smoothly into limiting.
The device matches the performance of an AGC
amplifier but shows none of the AGC bouncing and
attack characteristics.
12-3214(F).r3
Figure 1. LG1605DXB Block Diagram
110 pF
25 kΩ
110 pF –+
13 14
2
3V–OUT
CHIP BOUNDARY
GND
1, 4, 5, 6, 15, 167
VBR
8
+
–
–
+
9
10
11
12
110 pF
50 Ω
VSS
V+OUT
VBS
VBF
V+REF
V+IN
V–IN
V–REF
25 kΩ
+
–
–
+
50 Ω
Data Sheet
LG1605 DXB Limiting Amplifier Febru ary 1999
2Lucent Technologies Inc.
Functional Description (continued)
The amplifier has a virtually constant output delay for
input signal levels, varying across three decades. As a
result, the device has very low amplitude-to-phase con-
version, which makes it ultimately suitable f or applica-
tions in highly sensitiv e fiber-optic systems. Although
the amplifier is most sensitive when the input is ac cou-
pled (see Figure 3), a low offset (<25 mV) and a large
common-mode input range of 2 V make it useful in
applications that require a high-speed comparator as
well.
A unique input coupling arrangement allows for a fre-
quency response down into the low kHz range while
using coupling capacitors that are small enough to
maintain a good input return loss at high frequencies.
The outputs, when ac coupled, provide a good RF ter-
mination up to very high frequencies. The associated
ability to absorb reflections returning from the receiving
end is essential for preventing intersymbol interference
in fiber-optic systems.
The amplifier is a natural step-up interface between
receivers, such as the Lucent Technologies Micro-
eletronics Group Optoelectronics unit 1319 and regen-
erators like the Lucent Technologies Microelectronics
Group LG1600. The referred wideband input noise
(168 µVrms typical) allows for a <1e–9 bit error rate
(BER) for inputs down to 2 mVp-p (S/N ratio of
21.5 dB).
In SAW based clock recovery systems, with clock fre-
quencies as high as 2.5 GHz, the de vice can provide a
clock-limiting function in systems.
The LG1605DXB is available in a hermetically sealed,
16-lead, glass-metal surface-mount package and uses
a standard ECL supply.
Pin Information
The pinout for the LG1605DXB is shown in Figure 2.
12-3223(F)
Figure 2. Pin Diagram
GND
GND
1
2
3
4
V+REF
12
11
10
9
16 15 14 13
GND GND VBS
5678
GND GND
VBF
V+IN
V–IN
V–REF
VSS VBR
V+OUT
V–OUT
Data Sheet
February 1999 LG1605DXB Limiting Amplifier
3Lucent Technologies Inc.
Pin Information (continued)
The pin descriptions for the LG1605DXB are given in Table 1.
Table 1. Pin Descriptions
Pin Symbol Name/Description
2V
+OUT Positive Data Output.
3V
–OUT Negative Data Output.
7V
SS dc Supply Voltage.
8V
BR Bias Reference Voltage. Connect to nominal –1.5 V stable voltage refer-
ence, bypassed to GND with a capacitor ≥0.047 µF.
9V
–REF Data Negative Refer ence. Internally bypassed with 110 pF. Broadband
operation requires up-close external bypassing with a capacitor ≥0.047 µF,
matching the input coupling capacitor.
10 V–IN Negative Data Input. Requires ac-coupling capacitor and 50 Ω source or
termination.
11 V+IN Positive Data Input.
12 V+REF Data Positive Reference. See pin 9 above.
13 VBF Bias Force Voltage. Obsolete function, do not connect.
14 VBS Bias Sense Voltage. Internal test point, tracking VBR. Normally not con-
nected.
1, 4, 5, 6,
15, 16,
Pac kage
Back
GND Ground. For optimum performance, package back should contact board
ground plane. (See the Mounting and Connections section.)
Data Sheet
LG1605 DXB Limiting Amplifier Febru ary 1999
4Lucent 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 2. Absolute Maximum Ratings
Recommended Operating Conditions
Table 3. Recommended Operating Conditions
Handling Precautions
Although protection circuitry has been designed into this device, proper precautions should be taken to avoid expo-
sure to electrostatic discharge (ESD) during handling and mounting. Lucent employs a human-body model (HBM)
and a charged-device model (CDM) for ESD-susceptibility testing and protection 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 4. ESD Threshold
Mounting and Connections
Certain precautions must be taken when using solder. For installation using a constant temperature solder, temper-
atures of under 300 °C may be employed for periods of time up to 5 s, maximum. For installation with a soldering
iron (battery operated or nonswitching only), the soldering tip temperature should not be greater than 300 °C and
the soldering time for each lead must not exceed 5 s. This device is supplied with solder on the back of the pack-
age. Due to the high gain of the device, it is recommended to solder the back of the package to ground.
Parameter Min Max Unit
Supply Voltage Range (VSS)–70.5V
Power Dissipation — 1 W
Voltage (all pins) VSS 0.5 V
V+REF – V+IN —±2V
V–REF – V–IN —±2V
Storage Temperature Range –40 125 °C
Operating Case Temperature Range 0 100 °C
Parameter Symbol Min Max Unit
Case Temperature tCASE 070°C
Power Supply VSS –5.7 –4.7 V
HBM ESD Threshold
Device Voltage
LG1605DXB ≥200 V
Data Sheet
February 1999 LG1605DXB Limiting Amplifier
5Lucent Technologies Inc.
Mounting and Connections (continued)
Lucent Technologies/FORCE ICs assembly procedure recommendations for the LG1605DXB are as follo ws:
■Board solder pattern for the 1605DXB package base should not exceed 50% of the package base area.
■Back lighting can be used during the pic k and place operation to silhouette the package in order to eliminate
reflection problems with the solder on the bottom.
■Set the lead spacing tolerance to ±0.012 in.
■Insertion pressure should not exceed 125 g.
Electrical Characteristics
tCASE = 0 °C to 70 °C, VBR = –1.5 V, VSS = –4.7 V to –5.7 V, bit rate = 2.488 Mbits/s NRZ, and data pattern =
223 – 1 PRBS, unless otherwise indicated.
Note: Minimum and maximum v alues are testing requirements. Typical values are characteristics of the device and
are the result of engineering ev aluations. Typical values are for information purposes only and are not part of
the testing requirements.
1. All temperatures are case temperature, tCASE.
2. Parameter guaranteed by design or characterization and not production tested.
Parameter Symbol Conditions1Min Typ Max Unit
Data Input Voltage2V±IN Single-ended source — — 800 mVp-p
Data Input Voltage2V+IN – V–IN Differential source — — 1600 mVp-p
Input Offset Voltage V+REF – V–REF 40 °C/–5.2 V; 70 °C/–5.7 V — — 25 mV
Common-mode Input
Voltage Range VCMIN 25 °C, VSS = –5.2 V,
dc input coupling — –2 to –4 — V
Output Voltage V ±OUT — 400 550 — mVp-p
Output Pu ls e Wid th
Relative to Bit Period PW% Measured on V+OUT,
@ 40 °C and 70 °C 90 100 110 %
Small-signal Output
Transition Time tr, tf 25 °C, 20% to 80%,
VIN = 8 mVp-p — 100 — ps
Small-signal Gain G 40 °C to 70 °C , VIN =
8 mVp-p 26 28 35 dB
Small-signal –3 dB
Bandwidth f3dB 25 °C, VIN = 8 mVp-p — 3 — GHz
Low-frequency –3 dB
Cut-off2fLF VIN = 8 mVp-p , input coupling
and bypassing as in Figure 3 —2.5 8kHz
Supply Current ISS — — 85 100 mA
Noise Figure2NF 25 °C, single-ended input — 15 16 dB
Input Referred Wideband
Noise Vnr 25 °C, single-ended input,
7 kHz—18 GHz — 168 — µVrms
Thermal Resistance θJC Junction to case — 30 — °C/W
Data Sheet
LG1605 DXB Limiting Amplifier Febru ary 1999
6Lucent Technologies Inc.
Test Circuit
12-3215(F)r.6
1. Depending on the desired supply rejection, VBR can be biased with a simple resistive divider, or resistor/zener diode network.
Alternatively, when the LG1605DXB is followed by the LG1600 clock and data regenerator, a resistive divider with bypassing capacitor may
be connected to pin 7 (VREF) of the LG1600 (VREF ≈ –3.2 V). This arrangement provides excellent temperature stability and power supply
rejection.
2. The outputs may be either ac coupled, as indicated, or dc terminated into 50 Ω. In the first case, good output return loss (see Figure 8) can be
obtained. The latter configuration provides a 0 mV to –600 mV output swing (when limiting) for easy interface to dc-coupled circuits. No i nput
coupling capacitors are needed when interfacing with the LG1600 or the 1319 receiver.
Figure 3. LG1605DXB Test Circuit (with TF1003C Test Fixture)
12-3216(F)r.3
1. Depending on the desired supply rejection, VBR can be biased with a simple resistive divider, or resistor/zener diode network.
Alternatively, when the LG1605DXB is followed by the LG1600 clock and data regenerator, a resistive divider with bypassing capacitor may
be connected to pin 7 (VREF) of the LG1600 (VREF ≈ –3.2 V). This arrangement provides excellent temperature stability and power supply
rejection.
Figure 4. Bias Options
110 pF
25 kΩ
110 pF –+
13 14
2
3V–OUT
CHIP BOUNDARY
GND 1, 4, 5, 6, 15, 167
VBR
8
+
–
–
+
9
10
11
12
110 pF
50 Ω
VSS
V+OUT
VBS
VBF
V+REF
V+IN
V–IN
V–REF
25 kΩ
+
–
–
+
50 Ω
50 Ω
50 Ω
5 Ω
5 Ω
LG1605DXB
SOURCE
0.047 µF
0.047 µF
50 Ω50 Ω
LOAD
(SEE NOTE 2)
TF1003C FIXTURE BOUNDARY
0.047 µF
+
1.5 V
RINT ≤ 10 kΩ
(SEE NOTE 1)
+5.2 V
5 Ω
0.047 µF
0.047 µF
0.047 µF
0.047 µF
0.047 µF
(SEE NOTE 1) 12 kΩ
≈ –3.2 V
(PIN 7 LG1600)
13.6 kΩ
–1.5 V
A. Using LG1600 Reference Voltage B. Using Supply Voltage
VREF
VBR
0.047 µF
(SEE NOTE 1) 8.2 kΩ
–5.2 V
20 kΩ
–1.5 V
VSS
VBR
Data Sheet
February 1999 LG1605DXB Limiting Amplifier
7Lucent Technologies Inc.
Typical Performance Characteristics
(at TA = 25 °C)
12-3217(F)
Figure 5. Input Return Loss S11
12-3218(F)
Figure 6. Gain S21
0123 5
FREQUENCY (GHz)
INPUT RETURN LOSS S
11
(dB)
4
–40
–20
–15
–10
–5
0
–25
–30
–35
0123 5
FREQUENCY (GHz)
GAIN S
21
(dB)
4
0
20
25
30
35
40
15
10
5
12-3219(F)
Figure 7. Isolation S12
12-3220(F)
Figure 8. Output Return Loss S22
0123 5
FREQUENCY (GH z)
ISOLATION S
12
(dB)
4
–80
–40
–30
–20
–10
0
–50
–60
–70
0123 5
FREQUENCY (GHz)
OUTPUT RETURN LOSS S
22
(dB)
4
–40
–20
–15
–10
–5
0
–25
–30
–35
HORIZONTAL: 100 ps/div, VERTICAL: 12 mV/div; VIN = 2.23 mVp-p, VOUT = 58.8 mVp-p, σ = 4.45 mVrms
Figure 9. Output Noise Histogram
Data Sheet
LG1605 DXB Limiting Amplifier Febru ary 1999
8Lucent Technologies Inc.
Typical Performance Characteristics (at TA = 25 °C) (continued)
6 mVp- p
12 mVp-p
50 mVp-p
400 mVp-p
800 mVp-p
HORIZONTAL: 100 ps/div
A. Input Voltage
VERTICAL: 200 mV/div
VERTICAL: 200 mV/div
VERTICAL: 200 mV/div
VERTICAL: 200 mV/div
VERTICAL: 200 mV/div
HORIZONTAL: 100 ps/div
B. Output Voltage
1 10 100 1000
10
1000
INPUT VOLTAGE (mVp-p)
100
OUTPUT VOLTAGE (mVp-p)
1 10 100 1000
INPUT VOLTAGE (mVp-p)
–10
10
8
6
4
2
0
–2
–4
–6
–8
RELATIVE DELAY (ps)
12-3221(F)
C. Output vs. Input 12-3222(F)
D. Input-to-Output Relative Delay
Figure 10. Limiting Characteristics
Data Sheet
February 1999 LG1605DXB Limiting Amplifier
9Lucent Technologies Inc.
Outline Diagram
16-Pin, Glass-Metal, Surface-Mount Package
Dimensions are in inches.
12-3224(F).b
0.012 TYP
0.030 TYP
0.230 SQ REF
+
0.366 ± 0.007
0.005
DETAIL A
0.050 MAX
0.000—0.004 0.020
0—4°
DETAIL A
+
9
13
1
5
R0.013
Data Sheet
LG1605 DXB Limiting Amplifier Febru ary 1999
10 Lucent Technologies Inc.
Ordering Information
Device Code Package Temperature Comcode
(Ordering Number)
LG1605DXB-TR16 Package on 16 mm tape and reel 0 °C to 70 °C 107142614
LG1605DXB-FLP Package in flat pack container 0 °C to 70 °C 107412025
TF1003C Test fixture — 10699013 8
Data Sheet
February 1999 LG1605DXB Limiting Amplifier
11Lucent Technologies Inc.
Appendix
The test fixture mentioned in the data sheet is sold separately and is described in detail below.
5-7208(F).r1
Note: Dot on test fixture lid indicates position of pin 1.
Figure 11. TF1003C Test Fixture
5-7209(F)
Figure 12. TF1003C Electrical Diagram
1234
12 11 10 9
13
14
15
16
8
7
6
5
V+IN V–IN
FIXTURE BOUNDARY
PACKA G E OUTLINE
VBR
VSS
VBF
VBS
V+OUT V–OUT
5 Ω
0.047 µF 0.047 µF
0.047 µF
0.047 µF
5 Ω
5 Ω
0.047 µF
Data Sheet
LG1605 DXB Limiting Amplifier Febru ary 1999
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.
FASTCAT
is a trademark of Lucent Technologies Inc.
Copyright © 1999 Lucent Technologies Inc.
All Rights Reserved
February 1999
DS98-400HSPL (Replaces DS96-236FCE)
For additional information, contact your Microelectronics Group Account Manager or the following:
INTERNET: http://www.lucent.com/micro
E-MAIL: docmaster@micro.lucent.com
N. AMERICA: Microelectronics Group, Lucent Technologies Inc., 555 Union Boulevard, Room 30L-15P -BA, Allentown, PA 18103
1-800-372-2447, FAX 610-712-4106 (In CANADA: 1-800-553-2448, FAX 610-712-4106)
ASIA PACIFIC: Microelectronics Group, Lucent Technologies Singapore Pte. Ltd., 77 Science Park D rive, #03-18 Cintech III, Singapore 118256
Tel. (65) 778 8833, FAX (65) 777 7495
CHIN A: Mic r oelect r onics Gr oup, Lu c en t Technolo gies (China) C o., Ltd., A- F2, 23/F, Zao Fong Universe Building, 1800 Zhong Sh an Xi Road, Shanghai
200233 P. R. China Tel. (86) 21 6440 0468, ext. 316, FAX (86) 21 6440 065 2
JAPAN: Microelectronics Group, Lucent Technologies Japan Ltd., 7-18, Higashi-Gotanda 2-chome, Shinagawa-ku, Tokyo 141, Japan
Tel. (81) 3 5421 1600, FAX (81) 3 5421 1700
EUROPE: Data Requests: MICROELECTRONICS GROUP DATALINE: Tel. (44) 1189 324 299, FAX (44) 1189 328 148
Technical Inquiries: GERMANY: (49) 89 95086 0 (Munich), UNITED KINGDOM: (44) 1344 865 900 (Ascot),
FRANCE: (33) 1 40 83 68 00 (Paris), SWEDEN: (4 6) 8 594 607 00 (Stockholm), FINLAND: (358) 9 4354 2800 (Helsinki),
ITALY : (39) 02 6608131 (Mila n), SPAIN: (34) 1 807 1441 (Madrid)
Appendix (continued)
5-7210(F)
Figure 13. TF1003C Connector Assignment (Pressure ring not shown.)
(11)
V+IN (10)
V–IN
(2)
V+OUT (3)
V–OUT
(13) VBF
(14) VBS
VBR (8)
VSS (7)
