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April 23, 1998
WHAT'S HOT IN THE DESIGN COMMUNITY
 When your MOSFET needs to drive a span of
loads, you must size the device for the largest load and thus incur the penalty of a
relatively large on-resistance and lower efficiency at lower load currents. The N-channel
Si-4806DY and complementary P-channel Si4807DY MOSFETs from Vishay-Siliconix each employ dual gates, so that you
can match driven gate size--and thus on-resistance--to the load. At full capacity, both
gates handle currents as high as 7.7A, with RDS(ON) of 0.022 ohms at VGS
of 10V; for loads as high as 2.2A, you drive just the smaller gate, which controls a
smaller part of the MOSFET reaping RDS(ON) of 0.25 ohms. The SO-8 devices cost
less than $1.68 (100,000).
--by Bill Schweber
Vishay-Siliconix, Santa
Clara, CA. 1-408-567-8220, fax 1-408-567-8995, www.siliconix.com.
Test & Measurement World magazine has an
opening for an electronic or electrical engineer. If you enjoy telling others about new
technologies and can communicate well, we may have a place for you as a technical editor.
You'll talk to key industry leaders and technologists. You'll write articles and work with
contributors who submit articles.
This job requires at least a BSEE and two years of hands-on experience.
Experience with ATE, wireless communications, or environmental testing is a plus. You need
excellent written and oral communication skills and must be able to juggle several
concurrent assignments. We pay engineering-level salaries commensurate with experience.
Please send us your résumé and salary requirement. If you have written a
conference paper or other work, please include it. Reply in confidence to: Jon Titus,
Editorial Director, Test & Measurement
World, 275 Washington St, Newton, MA 02158, jontitus@cahners.com. We are an equal
opportunity employer, M/F/D/V.
For all of its promise, Java has so far been limited mainly to producing
animated advertisements on Web pages. Now, Tektronix has
come up with a more utilitarian application: customizing its digital oscilloscopes for
applications such as disk-drive and power-supply testing. Although other scope
manufacturers, such as LeCroy Corp (www.lecroy.com), have for several years offered
application-specific scope enhancements, those other manufacturers have coded the
enhancements in machine language. The benefits of coding in Java will probably emerge
soon, however, Tektronix says. Future versions of the Tek packages may accept user-designed customization to
accommodate unique requirements.
Because of Java's portability, the packages will work with any scopes Tektronix develops in the future. Such scopes won't have to
use a 68040 µP--the type that the current TDS series uses. To adapt
machine-language-coded packages to a different µP, Tektronix
would have to re-engineer the packages. In addition, Tek
feels that it can deliver Java-based packages more quickly than it could deliver
machine-language packages.
The packages run in TDS 700C-series Option 2M scopes that Tektronix shipped after the packages' introduction. These
scopes include additional processor memory that the Java virtual machine requires. Scope
prices remain the same as that of earlier versions of scopes having the same model and
option numbers. Users load the packages via the scopes' floppy-disk drives. Thereafter,
the packages reside on the scopes' hard-disk drives. The initial packages are an $850
disk-drive application and a $350 power-supply application. Users must also purchase a
$150-per-scope Java license. This license covers an unlimited number of applications
installed on one scope. To demonstrate the concept, Tek
offers an enhanced printing application as a free download under "application support
files" at www.tek.com/Measurement/support.
This application allows printing waveforms as deep as 8M samples at the horizontal
resolution of your choice. Tek says that once users see
the printing application in action, any concerns about Java operating slowly will
disappear.
--by Dan Strassberg
Tektronix Inc, Beaverton, OR,
1-800-426-2200, www.tek.com/Measurement.
If you can use a Spice-to-IBIS (I/O Buffer Interface Specification)
converter to help with your I/O-buffer modeling work, check out Cadence's web page for a free copy of the company's
converter tool. You use IBIS models with some pc-board-analysis tools to represent board
components at the pin level. If you have Spice models available for these components, Cadence's tool saves time in generating models for use
with any simulators that can read IBIS-format files.
--by Jim Lipman
Cadence Design Systems, San
Jose, CA. 1-408-943-1234, fax 1-408-943-0513, www.cadence.com.
 For designs in which signals face the
real world, you're wise to implement protection against ESD voltage transients. The
DALC112S1 from SGS-Thomson Microelectronics protects as
many as six high-speed data lines via a pair of series-connected diodes per line that you
can use to clamp signals to the VCC rail; the 12 diodes come in an eight-lead
SOIC package, thus requiring minimal space on a pc board. The 5-pf/diode capacitance makes
this array appropriate for high-speed applications, such as Ethernet, token ring, or ATM
interfaces; set-top box connections; and PC graphics and video ports.
The diodes are suitable for nominal 5 and 12V systems, because they
withstand peak reverse voltages as high as 18V; repetitive peak forward current is 12A
maximum, and you can connect diodes in parallel to increase surge rating if you need a
higher value. The IC, with leakage current guaranteed to be less than 2 µA, costs $0.28
(500,000).
--by Bill Schweber
SGS-Thomson Microelectronics Inc,
Lincoln, MA. 1-781-259-0300, fax 1-781-259-4420, www.st.com.
 A two-IC data-access arrangement (DAA)
from Silicon Laboratories significantly reduces
pc-board area compared with traditional DAA implementations, which typically require a
combination of transformers, relays, and optoisolators. The Si3032A and companion Si3032B
Isolink implement a digital, solid-state DAA and include the analog front-end codec
between the DAA and system DSP. The IC pair eliminates the need for an isolation
transformer, relays, and the two-to-four-wire hybrid, and the ICs provide 2000V isolation.
The result reduces pc-board area to 1 sq in. vs 2 to 3 sq in., roughly halves the number
of associated passive components, and cuts power and cost compared with traditional
transformer-based techniques. A low-cost, high-voltage capacitor isolates both the modem
and the control signals, which share this same barrier, so an extra path is unnecessary.
Available in 16-pin SOICs, the devices provide 90-dB dynamic range in both the
transmitting and receiving paths and offers data rates compatible with 56-kbps modems. The
DAA also supports caller-ID and line-current monitoring.
Operating voltage is 3 to 5V for this $6.90 (10,000) pair, which meets US
FCC requirements; the Si3034 variation is available for telephony standards outside North
America.
--by Bill Schweber
Silicon Laboratories Inc,
Austin, TX. 1-512-416-8500, fax 1-512-416-9669, www.silabs.com.
Atmel's AT27C520 512-kbit,
one-time-programmable ROM integrates an 8-bit address latch and provides a direct
interface to 8051-series µCs, which multiplex lower-order address bits on the eight data
lines. Operating at 5V, the AT27C520 specifies a typical operating current of 8 mA.
Latched EPROMs offer lower chip count and board space than the alternative
design with a standard EPROM and a separate latch, assuming you don't also need the latch
for other external memory-mapped peripherals.
The AT27C520's 64 kbytes consume the entire external-address space of
standard 8051 processors. SGS-Thomson's 256-kbit M87C257,
a lower desnity alternative, comes in 28-pin DIPs and 32-lead PLCCs. Waferscale
Integration's PSD devices reconstruct port pins a design loses when you create the
controller's address and data buses and also include user-programmable logic. The AT27C520
costs $2.35 (1000) for the 90-nsec version.
--by Brian Dipert
Atmel Corp, San Jose, CA.
1-408-441-0311, www.atmel.com.
When Hewlett-Packard announced its
Infinium line of DSOs less than nine months ago, the company said that the scopes' Windows
95-based architecture would keep the product line a step ahead of its competition: The
continual, rapid evolution of PC technology would enable quick upgrades. HP is now making good on that pledge. By replacing the
scopes' original PC main board with a new board based on a 200-MHz AMD K6 µP (www.amd.com/k6/)
and using a 512-kbyte level-2 cache, HP has upped the
display rate to 1750 waveforms/sec. HP claims that this
rate is 10 times that of the line's major competitor--when the competitive scopes operate
in a comparable display mode. The higher update rate increases the scopes' duty cycle and
reduces the time needed to capture signal anomalies that occur infrequently and
unpredictably.
Because the main board accepts PC plug-in boards, HP was also able to add a 10-Mbps Ethernet interface. This
interface, which is compatible with the most popular LAN standard, allows engineers to
connect their DSOs to networked printers and to rapidly obtain high-quality printouts. In
addition, HP has enhanced the scope firmware to allow
users to enter meaningful signal names and other annotations on the waveforms displays.
Infinium prices begin at $9995 for a two-channel, 500-MHz-bandwidth unit
with an acquisition rate of 1G samples/sec/channel. The $29,995 top-of-the-line unit
offers 1.5-GHz bandwidth and takes 4G samples/sec/ channel when all four channels are
operating or an industry-leading (among general-purpose scopes) 8G samples/sec/channel
when two channels are in use.
--by Dan Strassberg
Hewlett-Packard Co, Santa Clara,
CA. 1-800-452-4844, ext 5788, www.hp.com/go/tmdir.
Two new tools help you verify your chips. The first, Simucad's Verilog-based Silos HyperFault system, reduces
digital-chip fault-simulation runtimes. With HyperFault, you do fault simulation at the
behavioral level of your design, as well as at RTL and gate level. The ability to simulate
part of your design at the behavioral level reduces the simulation time over simulating
the design at the RTL or gate level. You also can do either functional simulation or check
timing within the fault simulation using back-annotated delays in Standard Delay Format.
HyperFault simplifies fault simulation and reduces the time it takes to
make simulation runs. The tool uses a hypertrophic fault-simulation technique, which flags
faults as detected when they create enough differences from the fault-free reference
circuit. By eliminating these hypertrophic faults from further fault simulation, Simucad claims a two- to three-times reduction in
fault-simulation times. To further reduce fault-simulation runtime, you can use the tool
in a networked multiprocessor configuration with one master copy and a number of slave
copies of HyperFault. HyperFault controls fault simulation according to the capability of
each processor in the system, based on CPU speed and a memory limit that you define for
each processor. The tool adjusts the number of passes it needs for the fault simulation
based on the memory you've specified, minimizing memory swapping.
HyperFault runs on Unix or Windows NT. When you run the tool on a
processor network, you can use either a Unix- or NT-based machine, but not both. Master
configurations of HyperFault cost $24,000 for Unix and $18,000 for NT. Slave
configurations are one-half the cost of master configurations.
LogicVision offers its latest
product, icBIST 3.0, for at-speed testing and diagnosing digital- and mixed-signal chips.
Although the company describes the product as an "embedded automated-test-equipment
solution," the tool suite appears to be a compilation of previously released digital
logic, memory, and analog-block built-in self-test (BIST) and logic-scan tools with a few
enhancements. The enhancements include legacy intellectual-property (IP)-core support,
improved at-speed test of high-speed logic, and improved logic- and memory-BIST
diagnostics.
You use icBIST for functional testing of your system-on-chip design. The
tool produces Verilog or VHDL RTL soft cores that reside on a chip, typically taking 2000
to 10,000 gates of logic. These cores implement BIST logic for at-speed testing of
digital-logic, SRAM, DRAM, and ROM blocks along with analog-logic PLL and ADC blocks. The
tool assembles the test blocks into a scan chain that you access with 1149.1 boundary
scan. The icBIST tool also does at-speed testing of board-level SRAM and DRAM chips along
with board-level interconnects.
Available in July, icBIST 3.0 will become LogicVision's only product and will be available on
a per-chip-design basis with prices starting at $30,000. The price includes logic BIST,
1149.1 boundary scan, and full-scan automatic test-pattern-generation (ATPG). Your icBIST
cost can increase substantially based on how extensive a set of tests and diagnostics you
want. For example, ADC and PLL BIST cost $15,000 each, as does testing of board-level
memory chips or board-level interconnects. Legacy-IP-test support costs $6000, and on-chip
memory BIST costs $6000 for ROM and SRAM together and $10,000 for DRAM. For an additional
cost, you can also work with LogicVision to
include testing of other types of memories and analog circuitry.
--by Jim Lipman
Simucad, Union City, CA.
1-510-487-9700, fax 1-510-487-9721, www.simucad.com.
LogicVision, San Jose, CA.
1-408-453-0146, fax 1-408-467-1180, www.logicvision.com.
Stereo converter with 24-bit
resolution challenges even golden ears
 The audio market is striving toward
higher resolution in its A/D and D/A converters. Typical of this trend is the AK5392 from AKM Semiconductor, a 24-bit stereo A/D converter, which
achieves a typical dynamic range of 116 dB and an SNR of 105 dB. The monolithic
sigma-delta device operates from a 5V supply, or you can use dual-voltage supplies (5V for
analog, 3V for digital) to reduce power consumption to less than 500 mW. Available in a
28-lead SOP package, the IC costs $19.95 (5000).
--by Bill Schweber
AKM Semiconductor Inc, San Jose,
CA. 1-408-436-8580, fax 1-408-436-7591, www.akm.com.
You never outgrow the need for analog
filters--
even in the digital world
 Digital may be the trend, but Nyquist
shows that you still need analog filters for antialiasing and reconstruction. Linear Technology's LTC1067 universal-filter
building-block IC consists of a pair of identical second-order filter sections. The
16-pin, narrow-SSOP device lets you build bandpass-, lowpass-, highpass-, notch-, and
allpass-response filters by adding a few resistors. You set the corner frequency for this
switched-capacitor configuration by varying the applied clock, and you can achieve an
80-dB dynamic range from a 3.3V supply, although the filter can operate with supplies as
high as ±5V. Maximum clock frequency is 250 kHz, and clock-to-center- frequency ratio is
100- or 50-to-1, depending on which of two versions you select. LTC offers filter-design
software to let you select component and clock values to achieve your desired cutoff
frequency, ripple, and stopband attenuation for this $3.50 (1000) IC.
For filtering digital video waveforms after they pass through their
reconstruction DACs, the Micro Linear Corp ML6428
active-filter IC eliminates as many as 16 discrete components as well as the aggravation
associated with filter design and implementation. The $1.50 (1000), eight-lead SOIC
accepts 1Vp-p Y and C video inputs (known as S-video), and its outputs include
amplified, filtered Y and C signals as well as composite video formed by summing the Y and
C signals. The S-video outputs can drive 2Vp-p into a 150 ohm load, and the
composite output can drive a 75 ohm load to the same amplitude span; internal gain for the
filter is ×2 for all outputs
--by Bill Schweber
Linear Technology Corp,
Milpitas, CA, 1-408-432-1900, fax 1-408-434-6441, www.linear-tech.com.
Micro Linear Corp, San
Jose, CA, 1-408-433-5200, www.microlinear.com.
 With all the fanfare surrounding the
latest ICs and active discrete components for cell phones and other Personal
Communications Service devices, it's easy to forget that the antenna--a passive device--is
a critical element of the signal path. The HAS047 from Toko
America is a helical stub antenna that supports frequency bands centered at both 859
and 1920 MHz, suitable for the dual-band wireless phones that are now becoming available.
The 33.5-mm (1.31-in.)-long, 9.4-mm (0.37-in.)-diameter antenna has 50 ohms impedance and
2.1 maximum VSWR; bandwidth is ±35 MHz for the lower band and ±70 MHz for the upper one.
A flexible elastomeric cover protects the $2 (10,000) unit, which comes with a choice of
standard connector options.
--by Bill Schweber
Toko America Inc, Mount
Prospect, IL. 1-847-297-0070, fax 847-699-1194, www.tokoam.com.
Spurred by the success of the 3Com (www.palmpilot.com)
Palm Pilot, both µP and operating-system vendors
are showing renewed interest in palmtop systems and personal digital assistants (PDAs).
Moreover, the contenders aren't limited to behemoths like Microsoft (www.microsoft.com).
For example, real-time OS vendor QNX Software Systems has
developed the In-Hand software tool kit that's targeted at handheld
applications--especially those with real-time requirements.
Available now for the AMD (www.amd.com) Elan SC400 microcontroller, the software suite
includes a real-time kernel, a Web browser, an e-mail client, a text editor, a
spreadsheet, a contact manager, a personal scheduler, PC Card support, and several games. QNX plans to ship the tool kit during the next quarter for
$19,995 and allow system vendors to quickly bring handhelds and other small systems to
market. The company will also negotiate prices on a royalty basis.
QNX and even Microsoft with Windows CE, however, face a tough
challenge in the handheld market. The Palm Pilot
has garnered the attention of more than 5000 software developers, and even staid IBM (www.ibm.com) has
licensed and is selling a version of it.
--by Maury Wright
QNX Software Systems, Kanata, ON,
Canada. 1-613-591-0931, www.qnx.com.
Spectrum Signal Processing's
latest digital radio, the TIM-SDR, combines an A/D converter, a digital downconverter, a
C44 DSP processor, and a D/A converter into a single-width mezzanine module. Digital
implementation of downconversion, filtering, and demodulation improves filter
characteristics, precision, and stability over analog circuitry. The receiver module
targets commercial and military surveillance applications, spectrum monitoring, cellular
fraud detection, software radio communications, and wireless base stations. A typical
implementation incorporates an RF translator that brings the antenna signal down into the
TIM-SDR's 20-kHz to 30-MHz IF input range. Spectrum's
SoftRadio software library then allows users to quickly implement a multichannel radio
receiver by providing C functions for frequency tuning, digital demodulation, automatic
gain control, and data transfers.
You can plug the TIM-SDR TIM-40 form factor module into Spectrum's carrier boards for the PCI, VME, or
VXI buses. The base price for the TIM-SDR single-channel radio-receiver module and initial
software is $5000.
--by Warren Webb
Spectrum Signal Processing,
Burnaby, BC, Canada. 1-604-421-5422, fax 1-604-421-1764 www.spectrumsignal.com.
 It's not just those glitzy cellular
phones that are using advanced communications technologies; the ubiquitous home cordless
phone is adapting them as well. Rockwell
Semiconductor's Hummingbird chip set extends the 900-MHz direct-sequence
spread-spectrum (DSSS) technique of its predecessor chip set to provide more integration,
better performance, and a two- rather than four-layer pc board. You can use the chip set
for a basic, low-cost cordless phone or use an expanded version to include features such
as caller ID, speakerphone, or two-line operation. With a 3.6V battery pack and 100-mV
output, a cordless phone using these devices provides a standby time of approximately 21
days and a talk time of 51/2 hours.
For the non-RF functions, the baseband IC comprises two devices in one
package. These devices contain audio-codec, DSSS-baseband-modem, audio-modem, and
microcontroller-core functions. Separately, the RF105 transceiver provides transmitting,
receiving, and frequency-synthesis functions using a direct-conversion architecture, along
with low-noise amplifier, mixers, filters, and variable-gain amplifiers. The RF106 power
amplifier supplies as much as 100 mW of transmitting power output. Note that you can use
the same devices for either the base-station or the handset design. The chip set
incorporates a smart hopping algorithm to quickly move the DSSS output past any
interference-prone channels. The chip set costs $15 (50,000).
--by Bill Schweber
Rockwell Semiconductor Systems,
Newport Beach, CA. 1-714-221-6996, www.rss.rockwell.com.
 Designs for applications requiring op
amps with significant power output rather than just analog-signal-handling ability have
difficulty handling dissipation in low-cost, efficient, easy-to-handle packages. Apex Microelectronics, a vendor of linear and PWM
power amplifiers, finds that the best approach is homemade: a power SIP package that you
can through-hole or surface mount and that dissipates as much as 100W with less than 1 in.2
of board space. Apex based the package on a
nickel-plated steel tab, with a beryllium-oxide ceramic base substrate, which acts as an
insulating but thermally conductive layer. To provide this plastic-lidded device with
protection nearly equivalent to that of a hermetically sealed package, the company filled
the cavity housing the die with silicon sealant before epoxy-sealing the lid.
The first amplifier from Apex
using this 10-pin package is the PA46, a class-C unit which provides as much as 5A
continuous output and as much as 85W dissipation, using the same die as the company's
established PA45, which comes in the venerable TO-3 housing. Applications for this
27V/µsec-slew-rate amplifier include magnetic-deflection subsystems, voice-coil and motor
drives, public-address systems, and noise-cancellation designs. Operating from ±15 to
±75V supplies, the 1×0.8-in. (2.5×2-cm), $29.86 (100) device lets you program its
quiescent current from 5 to 50 mA, a feature that the previous PA45 lacks because of
package-pin constraints. For additional flexibility, you provide external compensation so
you can tailor loop gain and bandwidth to your load and system dynamics. As is often
unfortunately necessary for power devices driving pesky real-world loads, the PA46 has
thermal, input, and output overload protection; you can also shut down its output stage to
minimize power consumption.
--by Bill Schweber
Apex Microelectronics Corp,
Tucson, AZ. 1-520-690-8618, fax 1-408-730-3788, www.apexmicrotech.com.
IC's dual-supply management solves
not-so-simple problem
Atmel is employing its AVR core in the
megaAVR family of large-memory microcontrollers. The family contains the same basic core
as Atmel's original AVR whose properties include a
16-bit, fixed-length instruction, a load/store architecture, and 32 general-purpose
registers. AVR can execute an instruction every clock by prefetching an instruction during
the previous instruction execution. As part of the evolution toward the use of higher
level languages, AVR also includes special instructions that support C programming.
The first two members of the megaAVR family, the ATmega103 and ATmega603,
have 128 and 64 kbytes of flash and 4 and 2 kbytes of EEPROM, respectively. Both devices
also have 4 kbytes of SRAM; a 10-bit, eight-channel ADC; a real-time clock; full-duplex
UART; and an SPI port. The 103 and 603 operate as fast as 8 MHz at 2.7 and 5V and come in
64-pin TQFPs. The 103 and 603 cost $15 and $11 (10,000), respectively.
--by Markus Levy
Atmel Corp, San Jose, CA.
1-408-441-0311, www.atmel.com.
It should be straightforward in principle to manage switchover when you
have two dc supplies that can source your rail: Just use a series diode for each so the
supply at higher potential supply is active. But when you look at the details and
drawbacks of this simple technique, you soon find that you need a more complex circuit to
do the job correctly. The LT1579 from Linear
Technology Corp eases the challenge, though. This 16-lead IC accepts two dc inputs;
provides uninterruptible output between the two with smooth switching action, even if you
suddenly remove one supply; protects against reverse battery installation; and includes
comparators and flag bits to monitor and indicate the status of each supply. The device
can source as much as 300-mA output current with a dropout voltage of 0.5V and 3%
output-voltage tolerance over line, load, and temperature variations. The IC is available
with fixed 3, 3.3, and 5V outputs and a variable 1.5 to 20V version is also available for
this $3.40 (1000) IC.
--by Bill Schweber
Linear Technology Corp,
Milpitas, CA. 1-408-432-1900, fax 1-408-434-6441, www.linear-tech.com.
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May 17 to 22
Society for Information Display Show,
Anaheim, CA, focuses on advances in display products, technology, systems, applications,
manufacturing, testing, and human factors. Palisades Institute for Research Services, New
York, NY. 1-212-620-3380. |
May 18 to 22
PC Developers' Expo and Conferences,
San Jose, CA, incorporates the PCI Plus conference, as well as the new I2O Plus
and USB Plus conferences. The show covers USB, I2O, PCI, Windows CE, IEEE 1394,
PC/104+, Windows 98/NT, embedded applications, PLDs, and CardBus. Annabooks Conferences,
San Diego, CA. 1-619-673-0870. |
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