LG1625AXF AGERE | Alldatasheet

Document overview

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Technical content

Features

■ High data-rate laser diode/LED driver ■ Adjustable output current ■ Operation up to 3 Gbits/s ■ Single –5.2 V power supply ■ 90 ps rise and fall times

Applications

■ SONET/SDH transmission systems ■ SONET/SDH test equipment ■ Optical transmitters

Description

The LG1625AXF is a gallium-arsenide (GaAs) laser diode driver to be used with direct modulated laser diodes in high-speed nonreturn-to-zero (NRZ) trans- mission systems. The device is made in a high-per- formance 0.9µm gate GaAs heterojunction FET technology that utilizes high-density MIM capacitors, airbridge interconnect, and NiCr film precision resis- tors. The device contains three cascaded stages, oper- ates with a single –5.2 V power supply and accepts ECL level inputs. Voltages control the modulated out- put current and laser prebias current. The LG1625AXF is available in a 24-lead hermetic, gull- wing package. A test fixture (TF1006A) with SMA connectors is available to allow quick evaluation of the LG1625AXF . 5-7865(F) Figure 1. Functional Diagram

ings for extended periods can adversely affect device reliability. Table 1. LG1625AXF Pin Description

  • I = input, O = output, P = power.

1, 6, 13, 22, 23 V SS1 P VSS1 Supply. –5.2 V power supply pin. Figure 5 on page 6, Typical T est Circuit). I Threshold Control. Input (eye crossing). 11 MK O Complementary Mark Density Output. 12 MK O Mark Density Output. 16 I OUT O Output. dc couple to laser cathode. 18 V PRE I Prebias Control Input. 19 V SS2 P VSS2 . –5.2 V supply for output prebias. 20 V SS3 P VSS3 . –5.2 V supply for output modulation. 21 V MOD I Modulation Current Control Input. Table 2. Absolute Maximum Ratings (at TA = 25 °C unless otherwise specified)

using these circuit parameters. and the soldering time for each lead must not exceed 5 seconds. Table 3. ESD Threshold Voltage

Lucent Technologies Inc. 5 Data Sheet June 1999 LG1625AXF Laser Driver

Electrical Characteristics

TA = 25°C, VSS1 = VSS2 = VSS3 = –5.2 V , VTH = –1.3 V , VMOD = –3.4 V , RL = 25Ω , data input = 600 mVp-p. Minimum and Maximum values are testing requirements. T ypical values are characteristics of the device and are the result of engineering evaluations. T ypical values are for information purposes only and are not part of the test- ing requirements. Stresses in excess of the absolute maximum ratings can cause permanent damage to the device. 5-7869(F) Figure 4. Typical Eye Diagram of IMOD Table 4. Electrical Characteristics HORZ.: 100 pS/DIV., VERT.: 15 mA/DIV.

Figure 5. LG1625AXF Typical Test Circuit ■ VSS bypass capacitors should be mounted close to the package. ■ Mark density (MK and MK) outputs are terminated with 1 kΩ pull-up resistors. ■ IMOD and IPRE can be measured and used to control VMOD and VPRE .

Figure 6. Output Modulation Current IMOD vs. the External Control Voltage VMOD

Lucent Technologies Inc. 9 Data Sheet June 1999 LG1625AXF Laser Driver Outline Diagram 24-Pin, Gull-Wing, Surface-Mount Package Dimensions are in inches. Tolerance is ±0.005 inches unless otherwise noted. 5-7875(F)r.2

Ordering Information

Device Type Comcode (Ordering Number) LG1625AXF 24-Lead Gull Wing 107529067 TF1006A T est Fixture 106733371 LUCENT 1625AXF XXXXXX 0.364 SQ. 0.260 0.050 0.012 0.008 BEFORE SOLDER DIP 0.604 ±0.015 TYP. R0.010 0.065 0.074 0.010 BEFORE SOLDER DIP1

The test fixture mentioned in the data sheet is sold separately and is described in detail below. Figure 9. TF1006A Test Fixture contact to the microstrip lines on the fixture through use of a pressure ring and two thumb screws. dered leads for dc bias lines. The TF1006A is preassembled and fully tested prior to shipment.

Figure 10. TF1006A Electrical Diagram ■ Due to possible stress during shipment, SMA connectors may be misaligned. ■ Check each SMA for continuity. ■ If necessary, realign and retighten with a 5/64 in. hex key wrench.

  1. T o insert a package, remove the two thumb screws and gently lift the pressure ring off of the test fixture.
  2. Place the pressure ring, cavity side up, on a flat ESD safe surface.
  3. Connect the metal tube to a suitable vacuum source with flexible tubing.
  4. Place the package, lid down, on a flat ESD safe surface. Locate pin 1 on the package.

rights under any patent accompany the sale of any such product(s) or information. Copyright © 1999 Lucent T echnologies Inc.

  1. Insert the package into the pressure ring (lid down) with pin 1 located next to the orientation mark and turn on

the vacuum. The vacuum will retain the package in the pressure ring during the following steps.

  1. Align the vertically conductive material on the circuit board.
  2. Place the pressure ring down over the alignment pins and gently tighten the thumb screws.
  3. Remove vacuum, if desired.

Note: Pressure ring not shown. Figure 11. TF1006A Connector Assignment