August 17, 1998

WHAT'S HOT IN THE DESIGN COMMUNITY

Physical-layer IC adds fiber to your interface diet

The ML6696 100Base-X fiber physical-layer interface eases 1300- and 820-nm Ethernet-link design by embodying the physical layer plus the LED driver and the postamplifier (quantizer).

It's easier to migrate to a fast Ethernet fiber-optic standard when you can use components that reduce the number of discrete ICs you need. The ML6696 fiber physical-layer interface from Micro Linear includes both the 100Base-FX physical layer as well as the LED and phototransistor interfaces, thus replacing a trio of ICs with a single component. This 64-pin TQFP device includes an LED driver and a postamplifier data quantizer. It complies with the current IEEE 803.2u standard for 1300-nm optical-window wavelengths and with the proposed 100Base-SX standard, which will use lower cost, 820-nm optical signals. Applications include fiber point-to-point links, network-interface cards, repeaters, and switches.

Within the ML6696, in addition to the optical-component interfaces, are a 4B/5B encoder/decoder, 125-MHz clock-recovery and -generation circuitry (you supply a 25-MHz reference clock), and an industry-standard media-independent interface for connection to higher-functional-level ICs. The 5V IC typically requires 200 mA when transmitting and 20 mA in power-down mode. (The LED current is nominally 70 mA, but you can set it lower using an external resistor.) The ML6696 costs $12.25 (1000). The $11.75 (1000) ML6695 variation does not include the encoder/decoder, which is appropriate for architectures that have that function as part of the controller.

—by Bill Schweber

Micro Linear Corp, San Jose, CA. 1-408-433-5200, www.microlinear.com.

ADC macrocells provide real-world port for VLSI devices

A quartet of 6- to 12-bit-resolution ADCs for signal-processing CMOS VLSI devices is available for license from Sarnoff. The macrocells include a dual 6-bit, 60M-sample/sec function operating from 3.3V and fabricated on a 0.35-µm process; a 10-bit, 40M-sample/sec function operating from 3.3V on a 0.5-µm process; and a 12-bit, 20M-sample/sec function operating from 5V on a 0.6-µm process. All three combine a successive-approximation register architecture with an autozero/autocalibration servo loop to eliminate external component trimming and matching. In addition, the vendor offers an 8-bit, 60M-sample/sec flash cell using a 1-µm process, using an "average-interpolating" technique to achieve a desirable speed-versus-power trade-off

—by Bill Schweber

Sarnoff Corp, Princeton, NJ. 1-609-734-3178, fax 1-609-734-2040, www.sarnoff.com.

Duplexer highlights passives' role in wireless-phone design

Lest you get too caught up in the chip sets, processors, and converters for cell phones, note that passive RF components are also critical to packing more functions into less space. Designed for Advanced Mobile Phone Services (AMPS) phones, a new antenna duplexer from Toko America separates and isolates both the transmitting and the receiving signal paths in a 19.6X9.6X3-mm-high chip using a three-layer dielectric structure.

The TDPF-836E-10 duplexer combines band-elimination and bandpass filtering with less than 2-dB insertion loss on the transmitter side and less than 3.5 dB on the receiver side. Attenuation of the transmitter signal into the receiver passband is 45 dB, whereas the complementary and less-critical attenuation of the receiver signal into the transmitter side is 36 dB. The duplexer has connections for the transmitter and receiver signals and the antenna and features second- and third-order harmonic rejection greater than 30 dB. The devices cost $5.32 (1000); Toko also offers similar duplexers for Global System for Mobile communications.

—by Bill Schweber

Toko America Inc, Mount Prospect, IL. 1-847-297-0070, fax 1-847-699-1194, www.tokoam.com.

Spectrum analyzer captures low-duty-cycle phenomena

Oscilloscopes aren't the only instruments with which EEs unearth the causes of devastating, yet infrequent, transient phenomena. The key to quickly characterizing transients is to spend more of the time acquiring data. With the introduction of the $43,500 Model 3066 dc to 3-GHz spectrum analyzer, Tektronix brings high-duty-cycle analysis to the frequency domain. The secret behind the improved transient-capture performance is the use of DSP technology. Instead of slowly sweeping a local oscillator across the frequency band of interest, the 3066 captures the spectrum in 5-MHz chunks, on which it uses FFTs to extract spectra. If the region of interest is no more than 5 MHz wide, the local oscillator (LO) remains fixed at one frequency and the instrument acquires data almost continuously. If you need to capture broader spectra, the LO moves in 5-MHz increments. You might say that the 3066 processes multiple frequencies in parallel, whereas conventional spectrum analyzers process multiple frequencies sequentially. Other features that help you quickly acquire important data are a frequency-mask trigger and the ability to display the data immediately before a trigger event. The downside of the FFT approach is that the unit offers a somewhat lower dynamic range than do conventional analyzers in the narrow-resolution-bandwidth mode.

—by Dan Strassberg

Tektronix Inc, Beaverton, OR. 1-800-426-2200, fax 1-503- 222-1542, www.tek.com/Measurement.

Off-the-shelf security creates virtual private networks

The new IPSECure software tool kits from Hi/fn speed the development of infrastructure products for virtual private networks. These portable source-code tool kits let OEMs implement the Internet Protocol Security (IPSEC) standard, which the Internet Engineering Task Force defined for IP network-layer security that enables end-to-end encryption and authentication. By using IPSECure with or without Hi/fn's 7711 encryption processor, OEMs can add security to any products using Transmission Control Protocol/IP communications. Products that can benefit from IPSECure include remote-access concentrators, routing switches, firewalls, and other embedded applications.

The pair of IPSECure network-security modules targets embedded systems that typically have limited resources, their own real-time kernels, and no hard disk. The tool kits implement packet-encryption processing, and the Internet Security Association Key Management Protocol module implements the negotiation for key exchange between the two virtual private-network end stations. The tool kits are written in 32-bit ANSI C, easing the task of porting them to any processor. However, using the modules with the 7711 encryption processor accelerates the algorithms. The 7711 processor performs computations that slow a system's main processor. By combining compression, encryption, and authentication on one chip, the 7711 compresses data to speed transmission and encrypts data for security.

The IPSECure tool kits are available for licensing in two methods. For use in a single product, such as network router and its derivative models, IPSECure entails a one-time fee of $100,000 for each module, with a 20% discount when purchasing both tool kits. For customers who buy Hi/fn's $58 (10,000) 7711 encryption processor, the initial charge for IPSECure is one-half of the licensing fee, with the balance amortized over a one-year period, according to the number of 7711 units purchased.

—by Stephen Kempainen

Hi/fn, San Jose, CA. 1-408-558-8066, fax 1-408-558-8074, www.hifn.com.

SONET/SDH devices integrate laser drivers

Vitesse Semiconductor introduces the VSC8161 and VSC8162 (SONET) and the synchronous-digital-hierarchy (SDH) digital optical-transmission standards. The devices integrate all the necessary functions to move data from a communication system's CMOS core circuitry to the laser modules that generate and receive the optical signal. The two GaAs devices exceed Bellcore jitter specifications and replace multiple bipolar devices, such as laser drivers and clock-recovery units. Typical applications include dense-wavelength-division-multiplexing equipment, SONET/SDH terminal equipment, and SONET/SDH add/drop multiplexers.

The VSC8161 integrates a 16-to-1 multiplexer, a 2.5-Gbps clock-multiplication unit, and the combination optical-carrier (OC)-48 and synchronous-transport-module (STM)-16 laser driver. This device accepts 16 bits of parallel data and a reference clock for the multiplication unit at 155-MHz frequency. The multiplexer serializes the data into a 2.5-Gbps data stream that is output through the laser driver. The laser driver sources 110 mA of current that is enough to drive today's and the next generation's laser diode modules for SONET and SDH.

TheVSC8162 integrates the OC-48/STM16 clock and data-recovery unit and the 1-to-16 demultiplexer. The clock and data-recovery unit recovers the serial data stream from the optical receiver, deserializes the data stream, and outputs the data from a 16-bit-wide port. This device overcomes the nonlinear effects inherent in optical-transmission media by providing phase-timing-adjustment circuitry in the clock-recovery unit. With this circuitry, the designer can adjust the recovered clock to the optimal point within the eye pattern for data recovery. Also, the clock-recovery unit uses a 19.44-MHz reference clock that permits staying locked under loss of signal conditions, and the VSC8162 indicates loss of lock and loss of reference-clock error conditions to the system.

Both devices will be available in September. The VSC8161 comesin a 100-pin PQFP and sells for$198 (1000). The VSC8162 comesin a 128-pin PQFP and sells for$158 (1000).

—by Stephen Kempainen

Vitesse Semiconductor, Camarillo, CA. 1-805-388-3700, fax 1-805-987-5896, www.vitesse.com.

ROMs give you that "synching" feeling

The shift to synchronous interfaces is well under way as both vendors and system engineers search for higher performance memories. Mask ROMs finally join their synchronous DRAM, SRAM, EEPROM, and flash-memory brethren with the introduction of Samsung's 32-Mbit KM23SV32205ST. Operating at 3.3V with zero-wait-state burst read speeds as high as 66 MHz across the 32-bit data bus, the device comes in an SDRAM-compatible, 86-pin TSOP II package.

The package isn't the only thing that looks like an SDRAM; the KM23SV32205ST also offers a DRAM-like multiplexed address bus and row-address-strobe (RAS), column-address-strobe (CAS), and other control signals. Although you might think you could straightforwardly hook both DRAM and DRAM-interface mask ROM to the same memory controller, reality is more complicated. Differences in RAS and CAS latencies and other timings between ROM and DRAM at a given clock frequency, along with the fact that the ROM specifies refresh and write operations as illegal (instead of simply ignoring them), imply the need for a semicustom controller design.

Currently sampling, the KM23SV32205ST costs $6 (1000), which Samsung estimates is 25% more expensive than a standard page-mode mask ROM. In exchange, Samsung claims that the KM23SV32205ST offers as much as 40% higher read performance than the asynchronous ROM alternative. As production ramps in the third quarter and beyond, Samsung hopes to reduce the price premium to less than 10%, a prediction that depends not only on customer demand, but also on functional- and pin-compatible alternative sources.

—by Brian Dipert

Samsung Semiconductor Inc, San Jose, CA. 1-408-954-7000, fax 1-408-954-7870, www.samsungsemi.com.

Power optocoupler is missing link for isolated real-world I/O

The virtues of isolated digital and analog I/O for real-world signals are well-known, but supplying isolated power to the signal-conditioning front end is a challenge—one that you usually meet using a transformer-coupled dc/dc converter.

You now have an alternative. Sunbelt Micro has developed a family of power optocouplers that combine infrared LEDs and photovoltaic cell arrays in a single package to produce an isolated dc/dc converter without transformers, oscillators, filters, or RFI concerns. The POC 101, POC 102, and POC 104 yield 0.45V dc at 4.2 mA, 0.9V dc at 1.8 mA, and 1.8V dc at 0.9 mA, respectively, from a 20-mA source current. Although this is not a large amount of power, it's enough to operate the front-end circuitry you can build using the many available low-power op amps and related components. One further caution: Despite these power-efficiency-obsessed times, these optical dc/dc devices are only about 4% efficient, much less than the greater-than-50% efficiency of a transformer-based isolated supply, but dissipation and efficiency are not priorities in many isolated interfaces.

All the devices are available in dual-in-line, 0.5X0.3X0.15-in. packages with 0.4-in. pin spacing and are tested to withstand 5000V rms between input and output. Prices begin at $21 (100).

—by Bill Schweber

Sunbelt Micro, Modular Products Division, North Attleboro, MA. 1-508-695-0203, fax 1-508-695-6076.

Aperture-grill-based, 19-in. monitor bursts $800 barrier

Designers have long found that large monitors increase productivity, but high costs have limited access to large screens, especially in small companies. Now, Nokia has announced a $799, 19-in. monitor that supports 1600X1200-pixel resolution at a 75-Hz refresh rate. This monitor is no low-cost, superstore special that ultimately only gives you a headache. The 446Xt relies on a Sony (www.sony.com) Trinitron CRT with its 0.26-in.-pitch, vertically slit aperture grill rather than the more common shadow-mask CRT. Nokia backs the monitor with a three-year warranty and specs reliability at 120,000 MTBF.

—by Maury Wright

Nokia Display Products, Sausalito, CA. 1-415-331-4244, www.nokia.com.

Digital video-interface chip set scales from VGA to SXGA

Silicon Image has added two chips to its PanelLink digital-interface family for flat-panel monitors having resolutions of 640X480 (VGA) to 1280X1064 pixels (SXGA). The PanelLink digital-interface standard is the basis of the Video Electronics Standards Association's Plug and Display standard and the Digital Flat Panel initiative specification. The new chip set is backward-compatible with previous PanelLink devices.

The SiI 150 universal transmitter and the SiI 151 receiver CMOS devices accommodate an operating-frequency range of 25 MHz for VGA resolution to 112 MHz for SXVA. The transmitter translates and multiplexes 24-bit color digital signals onto three differential pairs plus a clock pair for transmission to the display. The SiI 151 receiver in a flat-panel display automatically detects connection or disconnection of the interconnection cable and then synchronizes to the incoming signal whether it is from the SiI 150 or from previous-generation SiI 140 and SiI 100 transmitters.

The PanelLink chip set is available now. The SiI 150 costs $7, and the SiI 151 costs $11 (10,000).

—by Stephen Kempainen

Silicon Image, Cupertino, CA. 1-408-873-3111, fax 1-408-873-0446, www.siimage.com.

High-voltage op amps play in not glamorous—but critical—roles

Although 3V and lower voltage op amps get lots of attention, many applications, such as automated test equipment, battery charging and monitoring, bias-voltage control for LCD panels, and industrial-control systems need higher voltage rails. New devices from Burr-Brown and Linear Technology help you meet these applications' needs.

Operating from supplies as large as ±45V, the OPA445 from Burr-Brown nonetheless comes in a standard SO-8 package. (Don't assume that it's in a low-voltage circuit and touch it with your fingers!) This FET-inputop amp has 10-pA input bias current, 15V/µsec slew rate, and as much as 15-mA output current. The $2.44 (1000) device also offers power-supply rejection, CMRR, and open-loop gain values of 110, 95, and 105 dB, respectively. If you don't like the surface-mount package,you can get the OPA445 in eight-pin DIPs and TO-99 metal cans.

Linear Technology's LT1636 rail-to-rail input/output op amp handles supply voltages of 2.7 to 44V and can operate from low-value rails while handling common-mode voltages as high as 44V. Input offset voltage is 225 µA, and input bias current is 0.8 nA. The 200-kHz gain bandwidth product matches a 0.07V/µsec slew rate. Maximum supply current is 55 mA, dropping to 12 µA in shutdown mode; output currents can reach ±18 mA from a dual 15V supply. The eight-pin device in DIP, SO, and MSOP packages costs $1.45 (1000).

—by Bill Schweber

Burr-Brown Corp, Tucson, AZ. 1-520-746-1111, fax 1-520-746-7401, www.burr-brown.com.

Linear Technology Corp, Milpitas, CA. 1-408-432-1900, fax 1-408-434-6441, www.linear-tech.com. 

10/100/1000-Mbps Ethernet controller targets servers and workstations

Jato Technologies' new JT1001 10/100/1000 Ethernet controller debuts as the first product in the company's NetCelerator architecture. The product implements host offloading, bus acceleration, and high-speed data-transfer engines in one chip. In addition to the Ethernet-controller functions, the JT1001 offers integrated Transmission Control Protocol/Internet Protocol and Virtual-LAN-processing functions. The NetCelerator architecture combines networking systems and semiconductor perspectives into a state-machine device for low-cost and high-speed packet processing. The JT1001 comes with certified device drivers and licensable source code.

The JT1001 includes the gigabit media-independent interface for Ethernet, the media-independent interface for 1000Base-T on Category 5 cable, and the 1000Base-X fiber interface for 10/100 BaseT transmission. The device integrates the PCI bus to move data from the network to the server or workstation. The 32- and 64-bit PCI bus operates at 33 MHz, important for moving gigabit data streams to and from the network. The device is available in 256-bump BGAs and costs $60 (1000).

—by Stephen Kempainen

Jato, Austin, TX. 1-512-207-2100, fax 1-512-452-5592, www.jatotech.com.

Low-end UHF range further succumbs to system-on-a-chip receivers

You use the bottom of the UHF band for low-data-rate applications, such as keyless-entry systems, alarms, remote controls, and door openers because this band offers a good trade-off among circuitry complexity, cost, and attainable range. Micrel's single-chip MICRF01 receiver/data demodulator for 300- to 450-MHz operation is an on/off keyed-modulation receiver that needs few external components. The IC includes complete RF and IF tuning plus demodulation circuitry, providing an antenna-in-through-data-out signal path.

A patent-pending design in the IC eliminates the need for manual tuning and trimming, SAW filters, or inductors; an external 3-MHz, ±5%-accurate ceramic resonator is the typical frequency reference. The device's antenna RF reradiation, which can cause design hassles, is within regulatory limits. For a transmitter, you can use an inexpensive, inductor/capacitor-based architecture and achieve a typical range of 100 to 150m using a monopole receiver antenna and data rates as high as 4.8 kbps. Receiver output is a CMOS-logic-level demodulated signal, which you can directly interface to your system processor or decoder. The 5V device comes in a 14-pin DIP or SOIC, consumes 6.3 mA in normal operation and 2 mA with its reference oscillator powered down, and costs $3 (1000).

—by Bill Schweber

Micrel Inc, San Jose, CA. 1-408-944-0800, fax 1-408-944-0970, www.micrel.com.

Multiprotocol WAN transceiver IC pumps data from one supply

The SP505 multimode serial transceiver from Sipex Corp lets you invoke any one of eight interface standards via a software-supplied code. With this 80-pin QFP-housed IC, you get seven drivers and seven receivers that morph their electrical characteristics for RS-232C, V.35, V.36, EIA-530, EIA-530A, RS-449, RS-485, and RS-422 operation at rates as high as 10 Mbps. The IC includes internal termination resistors for V.35 drivers and receivers and V.11 receivers as needed.

The SP505 requires only a 5V supply; it uses a charge pump to develop other voltages. The device complies with NET1/NET2 and TRB2 standards, offers loop-back mode for diagnostic self-test, and lets you select three-state control for drivers and receivers if you desire this mode for half-duplex links. Further, you can operate the $21 (1000) IC as either a DTE or DCE device.

—by Bill Schweber

Sipex Corp, Billerica, MA. 1-978-667-8700, fax 1-978-670-9001, www.sipex.com.

Low-resolution quad DACs give you a handle on electronic trims

New devices from Motorola and Analog Devices join the ranks of relatively low-resolution, low-speed DACs that often let you reduce or eliminate manual trim circuitry in video displays, imaging equipment, automated test equipment, and mobile-communications handsets. These ICs give you more flexibility in design layout—along with cost savings—compared with mechanical trimming arrangements.

The MC144112 IC from Motorola, a quad voltage-output DAC with 6-bit resolution, comes in a 14-pin narrow-body package. You control the DACs' settings via the SPI bus, and you can cascade multiple ICs if you need more than four channels. Integral nonlinearity is -1.25 to +0.25 bit. Each DAC requires as little as 0.3 mA from a supply as low as 2.7V; standby current is a few microamps. The MC144112 costs $1.09 (10,000).

If you need another 2 bits of resolution, Analog Devices offers the AD7304 quad voltage-output DACs. The 16-pin IC operates from a 3 to 5V supply or bipolar 5V supplies and yields a rail-to-rail output swing. You can also use the DACs as multiplying devices with 2.6-MHz bandwidth by providing a varying external reference. Automatic reset on power-on sets all DAC outputs to zero scale; shutdown-mode current requirement is 40 µA. The SPI interface for this $3.25 (1000) device includes double-buffered data registers. A parallel interface, the similar $3.75 AD7305 in a 20-pin package, is also available.

—by Bill Schweber

Analog Devices Inc, Norwood, MA. 1-781-937-1428, fax 1-781-821-4273, www.analog.com.

Motorola Semiconductor Products, Phoenix, AZ. 1-602-413-4991,fax 1-602-413-7986, www.motorola.com/wireless-semi/.

| EDN Access | Feedback | Table of Contents |