AGERE LG1605DXB-TR16, LG1605DXB-FLP Datasheet

Data Sheet
February 1999

Features

■

28 dB gain, 34 dB differential

■

Large dynamic range: >60 dB

■

Wideband response: 8 kHz to 3 GHz

■

Extremely low ±4 ps delay skew across input range

■

Complementary 50 Ω I/Os

■

Surface-mount package

■

Standard ECL supply (400 mW)

Applications

■

Data/clock main amplifier SONET/SDH OC-48/
STM-16 transmission systems, DWDM systems

LG1605DXB Limiting Amplifier

■

Digital video transmission

■

Interface between 1319 receiver and LG1600
clock and data regenerator

■

High-speed comparator

Functional Description

The LG1605DXB is a GaAs wideband limiting ampli­fier with differential inputs and outputs that provides
28 dB of gain (34 dB differential) and 3 GHz of band­width 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 levels, 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.

V

V

–REF

–IN

V

+IN

V

+REF

10
11

12

9

110 pF

110 pF

50

50

BR

V

8

110 pF

25 k

Ω

Ω

25 k

–+

13 14

BF

V

SS

V

Ω

CHIP BOUNDARY

+––

+

Ω

V

GND

+––

BS

Figure 1. LG1605DXB Block Diagram

1, 4, 5, 6, 15, 167

3

–OUT

V

2

+

V

+OUT

12-3214(F).r3

Data Sheet

LG1605DXB Limiting Amplifier February 1999

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 con­version, which makes it ultimately suitable for applica­tions in highly sensitive fiber-optic systems. Although
the amplifier is most sensitive when the input is ac cou­pled (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 fre­quency 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 ter­mination up to very high frequencies. The associated

Pin Information

The pinout for the LG1605DXB is shown in Figure 2.

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 Micro­eletronics Group Optoelectronics unit 1319 and regen­erators 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 device 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.

GND

+OUT

V

–OUT

V

GND

BS

BF

GND GND V

16 15 14 13

1

2

3

4

5678

V

12

11

10

9

V

V

V

V

+REF

+IN

–IN

–REF

GND GND

VSSV

BR

12-3223(F)

Figure 2. Pin Diagram

2 Lucent Technologies Inc.

Data Sheet
February 1999 LG1605DXB Limiting Amplifier

Pin Information

(continued)

The pin descriptions for the LG1605DXB are given in Table 1.

Table 1. Pin Descriptions

Pin Symbol Name/Description

2V
3V
7V
8V

+OUT
–OUT

SS
BR

Positive Data Output.
Negative Data Output.
dc Supply Voltage.
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 Reference.

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
12 V
13 V
14 V

+IN

+REF

BF
BS

Positive Data Input.
Data Positive Ref erence.
Bias Force Voltage.
Bias Sense Voltage.

Obsolete function, do not connect.

Internal test point, tracking V

See pin 9 above.

nected.

1, 4, 5, 6,

15, 16,

GND

Ground.

For optimum performance, package back should contact board

ground plane. (See the Mounting and Connections section.)

Package

Back

. Normally not con-

BR

3Lucent Technologies Inc.

Data Sheet

LG1605DXB Limiting Amplifier February 1999

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

Parameter Min Max Unit

Supply Voltage Range (V

)–70.5V

SS

P ower Dissipation — 1 W
Voltage (all pins) V

– V

V
V

+REF
–REF

– V

+IN
–IN

SS

—±2V
—±2V

0.5 V

Storage Temperature Range –40 125 °C
Operating Case Temperature Range 0 100 °C

Recommended Operating Conditions

Table 3. Recommended Operating Conditions

Parameter Symbol Min Max Unit

Case Temperature t
Power Supply V

CASE

SS

070°C

–5.7 –4.7 V

Handling Precautions

Although protection circuitry has been designed into this device, proper precautions should be taken to avoid expo­sure 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 industry­wide standard has been adopted for the CDM. However, a standard HBM (resistance = 1500 Ω
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.

, capacitance =

Table 4. ESD Threshold

HBM ESD Threshold

Device Voltage

LG1605DXB ≥200 V

Mounting and Connections

Certain precautions must be taken when using solder. For installation using a constant temperature solder, temper­atures 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 pack­age. Due to the high gain of the device, it is recommended to solder the back of the package to ground.

4 Lucent Technologies Inc.