Avtech AVR-EB4-B-NXPB-SOD123W User manual

INSTRUCTIONS
MODEL AVR-EB4-B-NXPB-SOD123W
+0.5A / -1A REVERSE RECOVERY
MEASUREMENT SYSTEM
WITH 1.5 ns SWITCHING TIME
SERIAL NUMBER: 14258
A V T E C H E L E C T R O S Y S T E M S L T D .
N A N O S E C O N D W A V E F O R M E L E C T R O N I C S
S I N C E 1 9 7 5
[e-mail]
http://www.avtechpulse.com/
Tel: [phone] (USA & Canada)
or [phone] (Worldwide)
BOX 5120, LCD MERIVALE
OTTAWA, CANADA K2C3H5

WARRANTY
Avtech Electrosystems Ltd. warrants products of its manufacture to be free
from defects in material and workmanship under conditions of normal use. If,
within one year after delivery to the original owner, and after prepaid return by
the original owner, this Avtech product is found to be defective, Avtech shall at
its option repair or replace said defective item. This warranty does not apply to
units which have been dissembled, modified or subjected to conditions
exceeding the applicable specifications or ratings. This warranty is the extent of
the obligation assumed by Avtech with respect to this product and no other
warranty or guarantee is either expressed or implied.
TECHNICAL SUPPORT
Phone: [phone] (USA & Canada)
or [phone] (Worldwide)
E-mail: [e-mail]
World Wide Web: http://www.avtechpulse.com
2

TABLE OF CONTENTS
WARRANTY....................................................................................................................2
TECHNICAL SUPPORT..................................................................................................2
TABLE OF CONTENTS.................................................................................................. 3
INTRODUCTION............................................................................................................. 5
MODEL HISTORY................................................................................................................... 6
SPECIFICATIONS...........................................................................................................7
REGULATORY NOTES.................................................................................................. 8
FCC PART 18.......................................................................................................................... 8
EC DECLARATION OF CONFORMITY..................................................................................8
DIRECTIVE 2011/65/EU (RoHS).............................................................................................9
DIRECTIVE 2002/96/EC ( EEE)............................................................................................9
FIRM ARE LICENSING.......................................................................................................10
INSTALLATION.............................................................................................................11
VISUAL CHECK.................................................................................................................... 11
PO ER RATINGS................................................................................................................11
CONNECTION TO THE PO ER SUPPLY...........................................................................11
PROTECTION FROM ELECTRIC SHOCK...........................................................................12
ENVIRONMENTAL CONDITIONS........................................................................................13
FUSES........................................................................................................................... 14
AC FUSE REPLACEMENT...................................................................................................14
DC FUSE REPLACEMENT...................................................................................................15
FUSE RATINGS....................................................................................................................15
FRONT PANEL CONTROLS........................................................................................ 16
REAR PANEL CONTROLS..........................................................................................18
TIMING CONTROL........................................................................................................ 20
BASIC TIMING CONTROL....................................................................................................20
TRIGGER MODES................................................................................................................ 21
GATING MODES...................................................................................................................21
BASIC AMPLITUDE CONTROL...................................................................................22
SETTING THE AMPLITUDE LEVELS...................................................................................23
AMPLITUDE ACCURACY.....................................................................................................23
INCORRECT ORIENTATION................................................................................................24
3

ACCESSIBLE VOLTAGES...................................................................................................24
TEST IGS.................................................................................................................... 25
ALL TEST JIGS..................................................................................................................... 25
AVX-TRR-NXPB-SOD123 TEST JIG.................................................................................25
AVX-TRR-NXPB-SOD128..................................................................................................... 28
TYPICAL RESULTS......................................................................................................29
TYPICAL RESULTS: CMMR1S-02.......................................................................................29
TROUBLESHOOTING.................................................................................................. 32
PROGRAMMING YOUR PULSE GENERATOR...........................................................33
KEY PROGRAMMING COMMANDS....................................................................................33
ALL PROGRAMMING COMMANDS.....................................................................................33
MECHANICAL INFORMATION.....................................................................................36
TOP COVER REMOVAL....................................................................................................... 36
RACK MOUNTING................................................................................................................36
ELECTROMAGNETIC INTERFERENCE..............................................................................36
MAINTENANCE............................................................................................................ 37
REGULAR MAINTENANCE..................................................................................................37
CLEANING............................................................................................................................ 37
TRIGGER DAMAGE.............................................................................................................. 37
WIRING DIAGRAMS.....................................................................................................38
IRING OF AC PO ER.......................................................................................................38
PCB 158R6 - LO VOLTAGE PO ER SUPPLY................................................................39
PCB 168C - HIGH VOLTAGE DC PO ER SUPPLY............................................................40
PCB 201C – SAFETY INTERLOCK......................................................................................41
PCB 241F - SECONDARY PULSE IDTH OR DELAY CONTROL.....................................42
PCB 228D - OP AMP LEVEL SHIFTING..............................................................................43
PCB 104H - KEYPAD / DISPLAY BOARD...........................................................................44
MAIN IRING....................................................................................................................... 45
STANDARD TEST JIG IRING (AVX-TRR-NXPB-SOD123 )...........................................46
TEST JIG IRING (AVX-TRR-NXPB-SOD128)....................................................................47
PERFORMANCE CHECK SHEET................................................................................48
Manual Reference: /fileserver2/officefiles/instructword/avr-eb/avr-eb4-b-nxpa/AVR-EB4-B-NXPB-SOD123W,ed3.odt.
Last modified August 8, 2022.
Copyright © 2022 Avtech Electrosystems Ltd, All Rights Reserved.
4

INTRODUCTION
The AVR-EB4-B-NXPB-SOD123W is a high performance, GPIB/RS232/Ethernet-
equipped customized instrument capable of generating a bipolar waveform into a test
jig. Normally, a diode will be placed installed in the jig, allowing diode currents of up to
+0.5A and -1A to be generated. When used with a user-supplied oscilloscope, this
instrument is useful for measuring reverse recovery times (tRR) of 8 ns to 1 us.
The AVR-EB4-B-NXPB-SOD123W mainframe generates two pulses internally, which
are combined using a resistor/capacitor network.
A 100 us wide forward-bias pulse of V1 = +1 to +120V is connected to the mainframe
output through a 175Ω resistance. With a diode DUT (with a forward voltage drop of
VDIODE) and another 25Ω total resistance in the connected jig and oscilloscope, the
forward bias current is given by:
IF = (V1 – VDIODE) / 200Ω, approximately
+0.5A maximum, approximately
80 us after the forward bias pulse starts, a 2 us wide reverse-bias pulse of V2 = -7.5 to -
84V is capacitively coupled to the mainframe output. This generates a current of:
IR = IF + (V2 / 50Ω), approximately
-1A maximum, approximately
The forward-to-reverse switching time is 1.5 ns (10%-90%).
The maximum reverse voltage that will develop across the DUT is:
VRMAX = IR × 50Ω
The DUT breakdown voltage must exceed this value.
The AVR-EB4-B-NXPB-SOD123W includes one AVX-TRR-NXPB-SOD123W diode test
jig. The instrument mainframe is connected to the test jig using two coaxial cables and
one DB-9 control cable. This jig accepts SOD123W packages.
The test jig output should be terminated with 50 Ohms, and connected to a high-
bandwidth (> 400 MHz) oscilloscope. The voltage across this resistance is directly
proportional to the current through the diode. By observing the current waveform
through the diode, the reverse recovery time may be determined.
While the provided test jig is intended to be flexible and easy to use, users can also
develop their own test jigs easily.
The AVR-EB4-B-NXPB-SOD123W may also be provided with different or additional a
customized test jigs, to meet particular customer package requirements.
5

The AVR-EB4-B-NXPB-SOD123W includes an internal trigger source, but it can also be
triggered or gated by an external source. A front-panel pushbutton can also be used to
trigger the instrument.
The AVR-EB4-B-NXPB-SOD123W features front panel keyboard and adjust knob
control of the output pulse parameters along with a four line by 40-character backlit
LCD display of the output amplitude, pulse repetition frequency, and delay. The
instrument includes memory to store up to four complete instrument setups. The
operator may use the front panel or the computer interface to store a complete
“snapshot” of all key instrument settings, and recall this setup at a later time.
This instrument is intended for use in research, development, test and calibration
laboratories by qualified personnel.
MODEL HISTORY
The instrument mainframe output has the same waveform electrical specifications as
the previously-supplied customized AVR-EB4-B-NXPB S/N 12432 (supplied in 2011).
The included test jig is different. Jig and pulser differences may cause differences in
measured recovery time values between instruments.
6

SPECIFICATIONS
Model1: AVR-EB4-B-NXPB-SOD123W
Recovery type: Reverse recovery
Intended application: High-speed rectifiers
Basic waveform: A positive pulse interrupted by a negative pulse
Pulse polarity: - +
Diode current2,4 (approx.,
depends on VDIODE): -100 mA to -1 A +50 mA to + 500 mA
Pulse width (FWHM): 2 us 100 us
Maximum duty cycle: N/A
Rise time (10%-90%): 1.2 - 1.5 ns typically N/A
Maximum PRF: 1 kHz
Delay: 80 us after start of + pulse N/A
Coaxial cable to test jig
(supplied): Two 2 m / 6 feet, RG-58C/U cables.
Supplied test jig3: Model AVX-TRR-NXPB-SOD123W, for SOD123W packages
Mainframe connectors: Out: SMA
Other: BNC
GPIB and RS-232 control: Standard on -B units. See http://www.avtechpulse.com/gpib for details.
Trigger required: Ext trig mode: + 5 Volts, 10 ns or wider (TTL)
Gate input Active high or low, switchable. Suppresses triggering when active.
Power requirements: 100 - 240 Volts, 50 - 60 Hz
Dimensions: H x W x D: 100 mm x 430 mm x 375 mm (3.9” x 17” x 14.8”)
Chassis material: cast aluminum frame and handles, blue vinyl on aluminum cover plates
Temperature range: +5°C to +40°C
1) -B suffix indicates IEEE-488.2 GPIB and RS-232 control of amplitude, pulse width, PRF and delay (see http://www.avtechpulse.com/gpib).
2) For operation at amplitudes of less than 10% of full-scale, best results will be obtained by setting the amplitude near full-scale and using external
attenuators on the output.
3) Customized jigs available upon request.
4) The amplitude settings should not be relied upon for any degree of accuracy, because the dynamics of the device under test can affect the actual
generated waveforms. Amplitude settings should always be verified by oscilloscope measurements.
7

REGULATORY NOTES
FCC PART 18
This device complies with part 18 of the FCC rules for non-consumer industrial,
scientific and medical (ISM) equipment.
This instrument is enclosed in a rugged metal chassis and uses a filtered power entry
module (where applicable). The main output signal is provided on a shielded connector
that is intended to be used with shielded coaxial cabling and a shielded load. Under
these conditions, the interference potential of this instrument is low.
If interference is observed, check that appropriate well-shielded cabling is used on the
output connectors. Contact Avtech ([e-mail]) for advice if you are unsure
of the most appropriate cabling. Also, check that your load is adequately shielded. It
may be necessary to enclose the load in a metal enclosure.
If any of the connectors on the instrument are unused, they should be covered with
shielded metal “dust caps” to reduce the interference potential.
This instrument does not normally require regular maintenance to minimize interference
potential. However, if loose hardware or connectors are noted, they should be
tightened. Contact Avtech ([e-mail]) if you require assistance.
EC DECLARATION OF CONFORMITY
We Avtech Electrosystems Ltd.
P.O. Box 5120, LCD Merivale
Ottawa, Ontario
Canada K2C 3H5
declare that this pulse generator meets the intent of Directive 2004/108/EG for
Electromagnetic Compatibility. Compliance pertains to the following specifications as
listed in the official Journal of the European Communities:
EN 50081-1 Emission
EN 50082-1 Immunity
8

and that this pulse generator meets the intent of the Low Voltage Directive 2006/95/EC.
Compliance pertains to the following specifications as listed in the official Journal of the
European Communities:
EN 61010-1:2001 Safety requirements for electrical equipment for
measurement, control, and laboratory use
DIRECTIVE 2011/65/EU (RoHS)
We Avtech Electrosystems Ltd.
P.O. Box 5120, LCD Merivale
Ottawa, Ontario
Canada K2C 3H5
declare that, to the best of our knowledge, all electrical and electronic equipment (EEE)
sold by the company are in compliance with Directive 2011/65/EU of the European
Parliament and of the Council of 8 June 2011 on the restriction of the use of certain
hazardous substances in electrical and electronic equipment (also known as “RoHS
Recast”). In addition, this declaration of conformity is issued under the sole
responsibility of Avtech Electrosystems Ltd. Specifically, products manufactured do not
contain the substances listed in the table below in concentrations greater than the listed
maximum value.
Material/Substance Threshold level
Lead (Pb) 1000 ppm (0.1% by mass)
Mercury (Hg) 1000 ppm (0.1% by mass)
Hexavalent Chromium (Cr6+) 1000 ppm (0.1% by mass)
Polybrominated Biphenyls (PBB) 1000 ppm (0.1% by mass)
Polybrominated Diphenyl ethers (PBDE) 1000 ppm (0.1% by mass)
Cadmium (Cd) 100 ppm (0.01% by mass)
Bis(2-ethylhexyl) phthalate (DEHP) 1000 ppm (0.1% by mass)
Butyl benzyl phthalate (BBP) 1000 ppm (0.1% by mass)
Dibutyl phthalate (DBP) 1000 ppm (0.1% by mass)
Diisobutyl phthalate (DIBP) 1000 ppm (0.1% by mass)
DIRECTIVE 2002/96/EC (WEEE)
European customers who have purchased this equipment directly from Avtech will have
completed a “WEEE Responsibility Agreement” form, accepting responsibility for WEEE
compliance (as mandated in Directive 2002/96/EC of the European Union and local
9

laws) on behalf of the customer, as provided for under Article 9 of Directive
2002/96/EC.
Customers who have purchased Avtech equipment through local representatives
should consult with the representative to determine who has responsibility for WEEE
compliance. Normally, such responsibilities with lie with the representative, unless other
arrangements (under Article 9) have been made.
Requirements for WEEE compliance may include registration of products with local
governments, reporting of recycling activities to local governments, and financing of
recycling activities.
FIRMWARE LICENSING
Instruments with firmware versions 5.00 or higher use open-source software internally.
Some of this software requires that the source code be made available to the user as a
condition of its licensing. This source code is available upon request (contact
[e-mail]).
Earlier firmware versions do not contain any open source software.
10

INSTALLATION
VISUAL CHECK
After unpacking the instrument, examine to ensure that it has not been damaged in
shipment. Visually inspect all connectors, knobs, liquid crystal displays (LCDs), and the
handles. If the instrument has been damaged, file a claim immediately with the
company that transported the instrument.
The following items should be with the instrument:
1. One power cord.
2. One GPIB cable
3. Two instrumentation manuals (this manual and the “Programming Manual for -B
Instruments”).
4. One test jig, with a hinged lid.
5. Two 2 m lengths of SMA-to-SMA coaxial cable.
6. One 60 cm length of SMA-to-SMA coaxial cable.
7. One 2 meter DB-9 control cable.
POWER RATINGS
This instrument is intended to operate from 100 - 240 V, 50 - 60 Hz.
The maximum power consumption is 57 Watts. Please see the “FUSES” section for
information about the appropriate AC and DC fuses.
This instrument is an “Installation Category II” instrument, intended for operation from a
normal single-phase supply.
CONNECTION TO THE POWER SUPPLY
An IEC-320 three-pronged recessed male socket is provided on the back panel for AC
power connection to the instrument. One end of the detachable power cord that is
supplied with the instrument plugs into this socket. The other end of the detachable
power cord plugs into the local mains supply. Use only the cable supplied with the
instrument. The mains supply must be earthed, and the cord used to connect the
instrument to the mains supply must provide an earth connection. (The supplied cord
does this.)
Warning: Failure to use a grounded outlet may result in injury or death due to
electric shock. This product uses a power cord with a ground connection. It must be
connected to a properly grounded outlet. The instrument chassis is connected to the
ground wire in the power cord.
11

The table below describes the power cord that is normally supplied with this instrument,
depending on the destination region:
Destination Region Description Option Manufacturer Part Number
United Kingdom, Hong Kong,
Singapore, Malaysia
BS 1363,
230V, 50 Hz -AC00 Qualtek 370001-E01
Australia, New Zealand AS 3112:2000,
230-240V, 50 Hz -AC01 Qualtek 374003-A01
Continental Europe, Korea,
Indonesia, Russia
European CEE 7/7
“Schuko” 230V, 50 Hz -AC02 Qualtek 364002-D01
North America, Taiwan NEMA 5-15,
120V, 60 Hz -AC03 Qualtek 312007-01
Switzerland SEV 1011,
230V, 50 Hz -AC06 Qualtek 378001-E01
South Africa, India SABS 164-1,
220-250V, 50 Hz -AC17 Volex 2131H 10 C3
Japan JIS 8303,
100V, 50-60 Hz -AC18 Qualtek 397002-01
Israel SI 32,
220V, 50 Hz -AC19 Qualtek 398001-01
China GB 1002-1 / 2099-1,
220V, 50 Hz -AC22 Qualtek 399012-01
PROTECTION FROM ELECTRIC SHOCK
Operators of this instrument must be protected from electric shock at all times. The
owner must ensure that operators are prevented access and/or are insulated from
every connection point. In some cases, connections must be exposed to potential
human contact. Operators must be trained to protect themselves from the risk of electric
shock. This instrument is intended for use by qualified personnel who recognize shock
hazards and are familiar with safety precautions required to avoid possibly injury. In
particular, operators should:
1. Keep exposed high-voltage wiring to an absolute minimum.
2. Wherever possible, use shielded connectors and cabling.
3. Connect and disconnect loads and cables only when the instrument is turned off.
4. Keep in mind that all cables, connectors, oscilloscope probes, and loads must
have an appropriate voltage rating.
5. Do not attempt any repairs on the instrument, beyond the fuse replacement
procedures described in this manual. Contact Avtech technical support (see
12

page 2 for contact information) if the instrument requires servicing. Service is to
be performed solely by qualified service personnel.
ENVIRONMENTAL CONDITIONS
This instrument is intended for use under the following conditions:
1. indoor use;
2. altitude up to 2 000 m;
3. temperature 5 °C to 40 °C;
4. maximum relative humidity 80 % for temperatures up to 31 °C decreasing
linearly to 50 % relative humidity at 40 °C;
5. Mains supply voltage fluctuations up to ±10 % of the nominal voltage;
6. no pollution or only dry, non-conductive pollution.
13

FUSES
This instrument contains four fuses. All are accessible from the rear-panel. Two protect
the AC prime power input, and two protect the internal DC power supplies. The
locations of the fuses on the rear panel are shown in the figure below:
AC FUSE REPLACEMENT
To physically access the AC fuses, the power cord must be detached from the rear
panel of the instrument. The fuse drawer may then be extracted using a small flat-head
screwdriver, as shown below:
14
Fuse
Drawer
Pry out the fuse
drawer using a
screwdriver.
Fuses #1 and #2
AC fuses)
Fuse #4
DC fuse)
Fuse #3
DC fuse)

DC FUSE REPLACEMENT
The DC fuses may be replaced by inserting the tip of a flat-head screwdriver into the
fuse holder slot, and rotating the slot counter-clockwise. The fuse and its carrier will
then pop out.
FUSE RATINGS
The following table lists the required fuses:
Fuses
Nominal
Mains
Voltage
Rating Case Size
Recommended Replacement Part
Littelfuse Part
Number
Digi-Key Stock
Number
#1, #2 (AC) 100-240V 0.5A, 250V,
Time-Delay 5×20 mm 0218.500HXP F2416-ND
#3 (DC) N/A 1.0A, 250V,
Time-Delay 5×20 mm 0218001.HXP F2419-ND
#4 (DC) N/A 1.0A, 250V,
Time-Delay 5×20 mm 0218001.HXP F2419-ND
The recommended fuse manufacturer is Littelfuse (http://www.littelfuse.com).
Replacement fuses may be easily obtained from Digi-Key (http://www.digikey.com) and
other distributors.
15

FRONT PANEL CONTROLS
1. POWER Switch . This is the main power switch. When turning the instrument on,
there is normally a delay of 10 seconds before anything is shown on the main
display, as the internal operating system boots up.
2. OVERLOAD Indicator . When the instrument is powered, this indicator is normally
green, indicating normal operation. If this indicator is yellow, an internal automatic
overload protection circuit has been tripped. If the unit is overloaded (by operating at
an exceedingly high duty cycle or by operating into a very low impedance), the
protective circuit will disable the output of the instrument and turn the indicator light
yellow. The light will stay yellow (i.e. output disabled) for about 5 seconds after
which the instrument will attempt to re-enable the output (i.e. light green) for
abOUT1 second. If the overload condition persists, the output will be disabled again
(i.e. light yellow) for another 5 seconds. If the overload condition has been removed,
the instrument will resume normal operation.
This overload indicator may flash yellow briefly at start-up. This is not a cause for
concern.
3. SYNC OUT . This connector supplies a SYNC output that can be used to trigger
other equipment, particularly oscilloscopes. This signal leads (or lags) the main
output by a duration set by the "DELAY" controls and has an approximate amplitude
of +3 Volts to RL > 50Ω with a pulse width of approximately 100 ns.
4. LIQUID CRYSTAL DISPLAY (LCD) . This LCD is used in conjunction with the
keypad to change the instrument settings. Normally, the main menu is displayed,
which lists the key adjustable parameters and their current values. The
“Programming Manual for -B Instruments” describes the menus and submenus in
detail.
16
23
45
1

5. KEYPAD .
Control Name Function
MOVE This moves the arrow pointer on the display.
CHANGE This is used to enter the submenu, or to select the operating
mode, pointed to by the arrow pointer.
×10 If one of the adjustable numeric parameters is displayed, this
increases the setting by a factor of ten.
÷10 If one of the adjustable numeric parameters is displayed, this
decreases the setting by a factor of ten.
+/- If one of the adjustable numeric parameters is displayed, and
this parameter can be both positive or negative, this changes the
sign of the parameter.
EXTRA FINE This changes the step size of the ADJUST knob. In the extra-
fine mode, the step size is twenty times finer than in the normal
mode. This button switches between the two step sizes.
ADJUST This large knob adjusts the value of any displayed numeric
adjustable values, such as frequency, pulse width, etc. The
adjust step size is set by the "EXTRA FINE" button.
When the main menu is displayed, this knob can be used to
move the arrow pointer.
17

REAR PANEL CONTROLS
Note: some connectors may be in different positions than shown above, depending on
the exact combination of options ordered.
1. AC POWER INPUT . An IEC-320 C14 three-pronged recessed male socket is
provided on the back panel for AC power connection to the instrument. One end of
the detachable power cord that is supplied with the instrument plugs into this socket.
2. AC FUSE DRAWER . The two fuses that protect the AC input are located in this
drawer. Please see the “FUSES” section of this manual for more information.
3. DC FUSES . These two fuses protect the internal DC power supplies. Please see the
“FUSES” sections of this manual for more information.
4. GATE . This TTL-level (0 and +5V) logic input can be used to gate the triggering of
the instrument. This input can be either active high or active low, depending on the
front panel settings or programming commands. (The instrument triggers normally
when this input is unconnected). When set to active high mode, this input is pulled-
down to ground by a 1 kΩ resistor. When set to active low mode, this input is pulled-
up to +5V by a 1 kΩ resistor.
5. TRIG . This TTL-level (0 and +5V) logic input can be used to trigger the instrument, if
the instrument is set to triggering externally. The instrument triggers on the rising
edge of this input. The input impedance of this input is 1 kΩ. (Depending on the
length of cable attached to this input, and the source driving it, it may be desirable to
add a coaxial 50 Ohm terminator to this input to provide a proper transmission line
termination. The Pasternack (www.pasternack.com) PE6008-50 BNC feed-thru 50
Ohm terminator is suggested for this purpose.)
18
1
45
2
3
8 76
9
OUT
CONTROL
GATE
RS-232
GPIB
TRIG
10

6. GPIB Connector . A standard GPIB cable can be attached to this connector to allow
the instrument to be computer-controlled. See the “Programming Manual for -B
Instruments” for more details on GPIB control.
7. RS-232 Connector. A standard serial cable with a 25-pin male connector can be
attached to this connector to allow the instrument to be computer-controlled. A user
name (“admin”) and a password (“default”, as shipped from the factory) are required
when logging into a serial terminal session. The internal controller attempts to auto-
sense the parity setting. It may be necessary to send a few return characters before
attempting a login in order to provide enough data to allow this auto-sensing to work.
(A standard Linux “agetty” process is used to implement serial control internally.) See
the “Programming Manual for -B Instruments” for more details on RS-232 control.
8. Network Connector . This Ethernet connector allows the instrument to be remotely
controlled using the VXI-11.3, ssh (secure shell), telnet, and http (web) protocols. See
the “Programming Manual for -B Instruments” for more details.
9. PULSE OUT CONNECTORS . These two BNC connectors provide the pulse output
signals to the test jig. Both should be connected to the corresponding inputs on the
test jig using two of the the supplied coaxial cables (2 meters in length).
These connectors are wired in parallel internally. It does not matter which “OUT”
connector on the mainframe is connected to which “IN” connector on the test jig.
Caution: Voltages as high as 120V may be present on the center conductors of
these output connectors. Avoid touching these conductors. Connect to these
connectors using standard coaxial cables, to ensure that the center conductors are not
exposed.
10.CONTROL Connector . This DB-9 female connector should be connected to the
corresponding connector on the test jig using the supplied DB-9 cable. This cable
contains the safety interlock signals that ensure that the test jig lid is closed.
19

TIMING CONTROL
BASIC TIMING CONTROL
This instrument can be triggered by its own internal clock or by an external TTL trigger
signal. In either case, two output channels respond to the trigger: PULSE and SYNC.
The PULSE output is a bipolar signal that may either drive a 50 Ohm load, or the test jig
described later. The positive and negative amplitudes are adjustable. The pulse widths
and delays are not adjustable.
The SYNC pulse is a fixed-width TTL-level reference pulse used to trigger oscilloscopes
or other measurement systems.
These pulses are illustrated below, assuming internal triggering:
The forward-bias pulse (V1) is approximately 100 us wide, and has a slow rise time
(governed by the R1 × C2 time constant – see equivalent circuit in the “BASIC
AMPLITUDE CONTROL” section for for details about R1 and C2.)
After 80 us, V1 has reached a stable voltage, and the SYNC output pulse is generated
(to allow triggering of oscilloscopes). Shortly after the end of the SYNC pulse, the
negative pulse (V2) is triggered, and is coupled onto the output signal. The negative
pulse lasts 2 us, approximately. (V2 droops slightly during the 2 us time, since it is
capacitively coupled to the output. However, this droop can generally be ignored.) The
DUT reverse recovery transient will occur within this 2 us time. After the end of the V2
pulse, the waveform will complete the forward-bias pulse, but this occurs after the
recovery waveform of interest has been obtained.
20
SYNC OUT
(generated by the
internal oscillator)
SMALL PROPAGATION DELAY (~ 200 ns)
Mainframe OUT
With DUT = 0 Ohms
80 us
3V, FIXED
V1 (+),
VARIABLE
V2 (-),
VARIABLE
100 us
2 us
NOT TO SCALE
CURRENT
THROUGH DIODE
(DASHED LINE)
tRR