Tektronix 2520 Reference manual

www.tek.com/keithley

Model 2520 Pulsed Laser Diode Test System

Quick Reference Guide

2520-903-01 Rev. B / March 2003

*P2520-903-01B*

2520-903-01B

WARRANTY

Keithley Instruments, Inc. warrants this product to be free from defects in material and workmanship for a
period of 1 year from date of shipment.

Keithley Instruments, Inc. warrants the following items for 90 days from the date of shipment: probes, cables,
rechargeable batteries, diskettes, and documentation.

During the warranty period, we will, at our option, either repair or replace any product that proves to be defective.

To exercise this warranty, write or call your local Keithley representative, or contact Keithley headquarters in
Cleveland, Ohio. You will be given prompt assistance and return instructions. Send the product, transportation
prepaid, to the indicated service facility. Repairs will be made and the product returned, transportation prepaid.
Repaired or replaced products are warranted for the balance of the original warranty period, or at least 90 days.

LIMITATION OF WARRANTY

This warranty does not apply to defects resulting from product modification without Keithley’s express written
consent, or misuse of any product or part. This warranty also does not apply to fuses, software, non-rechargeable
batteries, damage from battery leakage, or problems arising from normal wear or failure to follow instructions.

THIS WARRANTY IS IN LIEU OF ALL OTHER WARRANTIES, EXPRESSED OR IMPLIED, INCLUD­ING ANY IMPLIED WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR USE.
THE REMEDIES PROVIDED HEREIN ARE BUYER’S SOLE AND EXCLUSIVE REMEDIES.

NEITHER KEITHLEY INSTRUMENTS, INC. NOR ANY OF ITS EMPLOYEES SHALL BE LIABLE FOR
ANY DIRECT, INDIRECT, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF
THE USE OF ITS INSTRUMENTS AND SOFTWARE EVEN IF KEITHLEY INSTRUMENTS, INC., HAS
BEEN ADVISED IN ADVANCE OF THE POSSIBILITY OF SUCH DAMAGES. SUCH EXCLUDED DAM­AGES SHALL INCLUDE, BUT ARE NOT LIMITED TO: COSTS OF REMOVAL AND INSTALLATION,
LOSSES SUSTAINED AS THE RESULT OF INJURY TO ANY PERSON, OR DAMAGE TO PROPERTY.

Keithley Instruments, Inc.

Sales Offices: BELGIUM: Bergensesteenweg 709 • B-1600 Sint-Pieters-Leeuw • 02-363 00 40 • Fax: [phone]

CHINA: Yuan Chen Xin Building, Room 705 • 12 Yumin Road, Dewai, Madian • Beijing 100029 • 8610-8225-1886 • Fax: [phone]
FINLAND: Tietäjäntie 2 • 02130 Espoo • Phone: [phone] • Fax: [phone]
FRANCE: 3, allée des Garays • 91127 Palaiseau Cédex • 01-64 53 20 20 • Fax: [phone]
GERMANY: Landsberger Strasse 65 • 82110 Germering • 089/84 93 07-40 • Fax: [phone]
GREAT BRITAIN: Unit 2 Commerce Park, Brunel Road • Theale • Berkshire RG7 4AB • 0118 929 7500 • Fax: [phone]
INDIA: 1/5 Eagles Street • Langford Town • Bangalore 560 025 • 080 212 8027 • Fax: [phone]
ITALY: Viale San Gimignano, 38 • 20146 Milano • 02-48 39 16 01 • Fax: [phone]
JAPAN: New Pier Takeshiba North Tower 13F • 11-1, Kaigan 1-chome • Minato-ku, Tokyo 105-0022 • 81-3-5733-7555 • Fax: [phone]
KOREA: 2FL., URI Building • 2-14 Yangjae-Dong • Seocho-Gu, Seoul 137-888 • 82-2-574-7778 • Fax: [phone]
NETHERLANDS: Postbus 559 • 4200 AN Gorinchem • 0183-635333 • Fax: [phone]
SWEDEN: c/o Regus Business Centre • Frosundaviks Allé 15, 4tr • 169 70 Solna • 08-509 04 600 • Fax: [phone]
TAIWAN: 13F-3. No. 6, Lane 99 Pu-Ding Road • Hsinchu, Taiwan, R.O.C. • 886-3-572-9077 • Fax: [phone]

28775 Aurora Road • Cleveland, Ohio 44139 • 440-248-0400 • Fax: [phone]

1-888-KEITHLEY (534-8453) • www.keithley.com

1/03

Model 2520

Pulsed Laser Diode Test System

Quick Reference Guide

©2001, Keithley Instruments, Inc.

All rights reserved.

Cleveland, Ohio, U.S.A.

Second Printing, March 2003

Document Number: 2520-903-01 Rev. B

Manual Print History

The print history shown below lists the printing dates of all Revisions and Addenda created
for this manual. The Revision Level letter increases alphabetically as the manual undergoes sub­sequent updates. Addenda, which are released between Revisions, contain important change in­formation that the user should incorporate immediately into the manual. Addenda are numbered
sequentially. When a new Revision is created, all Addenda associated with the previous Revision
of the manual are incorporated into the new Revision of the manual. Each new Revision includes
a revised copy of this print history page.

Revision A (Document Number 2520-903-01)................................................................. June 2001

Revision B (Document Number 2520-903-01) .............................................................. March 2003

All Keithley product names are trademarks or registered trademarks of Keithley Instruments, Inc.
Other brand names are trademarks or registered trademarks of their respective holders.

Safety precautions

The following safety precautions should be observed before using this product and any associated instrumentation. Although
some instruments and accessories would normally be used with nonhazardous voltages, there are situations where hazardous
conditions may be present.

This product is intended for use by qualified personnel who recognize shock hazards and are familiar with the safety precautions
required to avoid possible injury. Read and follow all installation, operation, and maintenance information carefully before using
the product. Refer to the user documentation for complete product specifications.

If the product is used in a manner not specified, the protection provided by the product warranty may be impaired.
The types of product users are:
Responsible body is the individual or group responsible for the use and maintenance of equipment, for ensuring that the

equipment is operated within its specifications and operating limits, and for ensuring that operators are adequately trained.
Operators use the product for its intended function. They must be trained in electrical safety procedures and proper use of the

instrument. They must be protected from electric shock and contact with hazardous live circuits.
Maintenance personnel perform routine procedures on the product to keep it operating properly, for example, setting the line

voltage or replacing consumable materials. Maintenance procedures are described in the user documentation. The procedures
explicitly state if the operator may perform them. Otherwise, they should be performed only by service personnel.

Service personnel are trained to work on live circuits, perform safe installations, and repair products. Only properly trained
service personnel may perform installation and service procedures.

Keithley Instruments products are designed for use with electrical signals that are measurement, control, and data I/O
connections, with low transient overvoltages, and must not be directly connected to mains voltage or to voltage sources with high
transient overvoltages. Measurement Category II (as referenced in IEC 60664) connections require protection for high transient
overvoltages often associated with local AC mains connections. Certain Keithley measuring inst ruments may be connected to
mains. These instruments will be marked as category II or higher.

Unless explicitly allowed in the specifications, operating manual, and instrument labels, do not connect any instrument to mains.
Exercise extreme caution when a shock hazard is present. Lethal voltage may be present on cable connector jacks or test

fixtures. The American National Standards Institute (ANSI) states that a shock hazard exists when voltage levels greater than
30 V RMS, 42.4 V peak, or 60 VDC are present. A good safety practice is to expect that hazardous voltage is present in any
unknown circuit before measuring.

Operators of this product must be protected from electric shock at all times. The responsible body must ensure that operators
are prevented access and/or insulated from every connection point. In some cases, connections must be exposed to potential
human contact. Product operators in these circumstances must be trained to protect themselves from the risk of electric shock. If
the circuit is capable of operating at or above 1000 V, no conductive part of the circuit may be exposed.

Do not connect switching cards directly to unlimited power circuits. They are intended to be used with impedance-limited
sources. NEVER connect switching cards directly to AC mains. When connecting sources to switching cards, install protective
devices to limit fault current and voltage to the card.

Before operating an instrument, ensure that the line cord is connected to a properly-grounded power receptacle. Inspect the
connecting cables, test leads, and jumpers for possible wear, cracks, or breaks before each use.

When installing equipment where access to the main power cord is restricted, such as rack mounting, a separate main input
power disconnect device must be provided in close proximity to the equipment and within easy reach of the operator.

For maximum safety, do not touch the product, test cables, or any other instruments while power is applied to the circuit under
test. ALWAYS remove power from the entire test system and discharge any capacitors before: connecting or disconnecting
cables or jumpers, installing or removing switching cards, or making internal changes, such as installing or removing jumpers.

Do not touch any object that could provide a current path to the common side of the circuit under test or power line (earth)
ground. Always make measurements with dry hands while standing on a dry, insulated surface capable of withstanding the
voltage being measured.

For safety, instruments and accessories must be used in accordance with the operating instructions. If the instruments or
accessories are used in a manner not specified in the operating instructions, the protection provided by the equipment may be
impaired.

Do not exceed the maximum signal levels of the instruments and accessories, as defined in the specifications and operating
information, and as shown on the instrument or test fixture panels, or switching card.

When fuses are used in a product, replace with the same type and rating for continued protection agains t fire hazard.
Chassis connections must only be used as shield connections for measuring circuits, NOT as protective earth (safety ground)

connections.
If you are using a test fixture, keep the lid closed while power is applied to the device under test. Safe operation requires the use

of a lid interlock.

screw is present, connect it to protective earth (safety ground) using the wire recommended in the user documentation.

If a

The
user documentation in all cases where the symbol is marked on the instrument.

The
contact with these voltages.

The

The

If this symbol is on a product, it indicates that mercury is present in the display lamp. Please note that the lamp must be
properly disposed of according to federal, state, and local laws.

The WARNING heading in the user documentation explains dangers that might result in personal injury or death. Always read
the associated information very carefully before performing the indicated pr ocedure.

The CAUTION heading in the user documentation explains hazards that could damage the instrument. Such damage may
invalidate the warranty.

Instrumentation and accessories shall not be connected to humans.
Before performing any maintenance, disconnect the line cord and all test cables.
To maintain protection from electric shock and fire, replacement components in mains circuits — including the power

transformer, test leads, and input jacks — must be purchased from Keithley Instruments. Standard fuses with applicable national
safety approvals may be used if the rating and type are the same. Other components that are not safety-related may be
purchased from other suppliers as long as they are equivalent to the original component (note that selected parts should be
purchased only through Keithley Instruments to maintain accuracy and functionality of the product). If yo u are unsure about the
applicability of a replacement component, call a Keithley Instruments office for information.

symbol on an instrument means caution, risk of danger. The user must refer to the operating instructions located in the

symbol on an instrument means caution, risk of electric shock. Use standard safety precautions to avoid personal

symbol on an instrument shows that the surface may be hot. Avoid personal contact to prevent burns.

symbol indicates a connection terminal to the equipment frame.

To clean an instrument, use a damp cloth or mild, water-based cleaner. Clean the exterior of the instrument only. Do n ot app ly
cleaner directly to the instrument or allow liquids to enter or spill on the instrument. Products that consist of a circuit board with
no case or chassis (e.g., a data acquisition board for installation into a computer) should never require cleaning if handled
according to instructions. If the board becomes contaminated and operation is affected, the board should be returned to the
factory for proper cleaning/servicing.

Safety precaution revision as of January 2013.

Table of Contents

Introduction ................................................................................ 1-1

Source and measure capabilities ................................................ 1-2

Front and rear panels .................................................................. 1-2

Navigating menus and entering numeric data ............................ 1-4

Menu navigation ................................................................. 1-4

Numeric data entry (EDIT keys) ......................................... 1-5

Editing source values ................................................................. 1-5

Editing keys ........................................................................ 1-5

Configuring laser diode source ........................................... 1-5

Setting photodiode detector source values .......................... 1-6

Display format ............................................................................ 1-7

Display example .................................................................. 1-7

Display units ....................................................................... 1-7

Basic connections ....................................................................... 1-8

Testhead connections .......................................................... 1-9

Interlock connections ........................................................ 1-10

Typical test connections .................................................... 1-11

Connection considerations ................................................ 1-11

Polarity .............................................................................. 1-12

Remote command programming ....................................... 1-12

Basic operation ......................................................................... 1-13

Remote command programming ....................................... 1-13

Settings to optimize performance ............................................ 1-16

Range ................................................................................ 1-16

Filter .................................................................................. 1-16

Features to enhance DUT testing ............................................. 1-18

Sweep operation ................................................................ 1-18

Performing sweeps ............................................................ 1-21

Math functions .................................................................. 1-24

List of Illustrations

Figure 1 Mainframe front panel ............................................................ 1-2

Figure 2 Mainframe rear panel ............................................................. 1-3

Figure 3 Testhead front panel ............................................................... 1-3

Figure 4 Testhead rear panel ................................................................. 1-4

Figure 5 Testhead connections .............................................................. 1-9

Figure 6 Remote interlock connections .............................................. 1-10

Figure 7 Laser diode test connections ................................................ 1-12

Figure 8 Linear staircase sweep .......................................................... 1-18

Figure 9 Logarithmic staircase sweep (example) ............................... 1-19

Figure 10 Custom pulse sweep (example) ............................................ 1-20

List of Tables

Table 1 SCPI commands for selecting polarity ................................ 1-12

Table 2 Basic operating procedure ................................................... 1-13

Table 3 SCPI commands for basic laser diode tests ......................... 1-14

Table 4 Basic laser diode test programming example ...................... 1-15

Table 5 Filter commands .................................................................. 1-17

Table 6 Filter programming example ............................................... 1-17

Table 7 Commands for linear and log staircase sweeps ................... 1-22

Table 8 Custom (list) sweep commands ........................................... 1-22

Table 9 Linear staircase sweep programming example .................... 1-23

Table 10 Custom sweep programming example ................................. 1-23

Table 11 Math function commands .................................................... 1-26

Table 12 Math function programming example ................................. 1-27

Model 2520

Pulsed Laser Diode Test System

Quick Reference Guide

Introduction

This guide is designed to familiarize users with fundamental operation (front panel and
remote) of the Keithley Model 2520 Pulsed Laser Diode Test System. For comprehensive
information on all aspects of Model 2520 operation, refer to the Model 2520 User’s
Manual.

Operation information in this guide is divided into four parts; (1) Fundamental source and
measure operations, (2) Settings to optimize performance, (3) Features to enhance DUT
testing and (4) More testing techniques. This format allows a new user to easily progress
from basic simple operation to more complex procedures.

Remote command programming

covered in this guide, the related SCPI commands for remote operation are summarized in
tables. Most commands have a query form. For example, :OUTPut ON turns all three
outputs on, while :OUTPut? requests the present state of the outputs. Note that the
Model 2520 must be addressed to talk after sending a query command.

For operations where command sequence is important, programming examples are pro­vided. The exact programming syntax will depend on the test program language.

—For the various Model 2520 operating modes

2 Quick Reference Guide

Source and measure capabilities

Laser diode source and measure:

• Source DC current from 10µA to 1A.

• Source current pulses from 10µA to 5A with pulse widths from 500ns to 5ms;
pulse delays (time between pulses) from 20µs to 500ms. (Pulse delay and width
depend on maximum duty cycle. See specifications.)

• Measure voltage from 0.33mV to 10.5V.

• Maximum current source DC power is 9.9W (1A @ 9.9V).

• Maximum current source pulse power is 45W (5A @ 9V).

Photodiode detector source and measure:

• Source bias voltage on each of two channels from 0V to ±20V.

• Measure current on each of two channels from 0.7µA to 105mA.

• Maximum current for each bias source is 100mA.

Front and rear panels

The front and rear panels of the Model 2520 mainframe and testhead are shown in

Figure 1, Figure 2, Figure 3, and Figure 4. The use of the various instrument controls and

connectors will be explained throughout this guide.

Figure 1

Mainframe front panel

2520 PULSED LASER DIODE TEST SYSTEM

D OUT

DETECTOR 2

VBI

4

TRIG

+/-

CONFIG

5

SWEEP

0000

MENU

PD

I

PD

3

DETECTOR 1

V

B

2

FILTER

89

COMM SETUP

EDIT

EXIT ENTER

RANGE

COMPL

RANGE

ON/OFF

OUTPUT

MATH

EDIT

LASER

V

L

I

1

0

LOCAL

RECALL

67

PW

DELAY

L