EDN — 03.14.96 integrated circuits EDN Access — The Design Information Source of the Electronics Industry

Integrated Circuits: March 14, 1996

3V FPGA is CardBus-compliant.The XC3100L-2 FPGA supports both the emerging CardBus and 3V PCI local-bus specifications. Gate arrays in the XC3100L family operate at frequencies of up to 85 MHz and reduce system power consumption by >50%, as compared to 5V devices. The 3V XC40 00L family offers gate densities of up to 20,000 usable gates. Both the XC3100L and XC4000L families are supported under the Xilinx XACTstep environment. The FPGAs come in a number of package types, including PLCC, PQFP, VQFP, TQFP, and BGA. Prices for the XC3100L and XC4000L series start at $31 and $54, respectively (100). Xilinx Inc, San Jose, CA. (408) 559-7778

Universal telephone IC minimizes component count.By integrating an enhanced speech-transmission circuit with a repertory dialer, melody generator, and ringer on a single chip, the AS2533 reduces external component count of the average telephone set by up to 80%. Preprogrammed pin options allow you to adapt the device to a wide variety of international post, telephone, and telegraph requirements. The AS2533 features a 31-digit redial function and repertory storage of 14 telephone numbers. Housed in a 28-pin DIP or SOIC, the chip costs $2 (OEM). Austria Mikro Systeme International, Cupertino, CA. (408) 865-1217.

PRML read-channel IC transfers 200 Mbps.A partial-read/maximum-likelihood (PRML) read/write IC for high-end mass-storage applications achieves data transfer rates of 50 to 200 Mbps and dissipates 800 mW. Fabricated in BiCMOS, the MC34250 packs an AGC; a seven-pole filter, seven-tap transversal equalizer; a Viterbi detector; a frequency synthesizer; an embedded servo demodulator and pulse detector; encoder/decoder; a data randomizer; fault-tolerant synchronization detection; write precompensation; and power management into a 64-pin TQFP. The part costs $19 (10,000). Motorola Semiconductor Products Sector, Phoenix, AZ. (602) 244-4556.

Multichannel ADC has 1.6-µsec S/H time. Useful for motor control, three-phase power systems, and cellular telephones, the AD7861 11-bit A/D converter simultaneously samples multiple signals with a S/H acquisition time of 1.6 µsec and an A/D-conversion time of 3.2 µsec/channel. The input stage of the AD7861 accommodates the types of signals frequently found in motor drives. Simultaneous sampling of the Vin1, Vin2, and Vin3 channels reduces phase coherency errors. The four auxiliary channels are multiplexed and are suitable for slower input signals. Housed in a 44-lead PLCC, the AD7861 costs $10 (1000). Analog Devices Inc, Wilmington, MA. (617) 937-1428.

Logic IC for mixed-voltage systems is sub-SSOP size. The TTL LMOS logic series is compatible with TTL output signals and can be used as a direct interface between 3 and 5V systems for mixed power-supply operation. Devices are housed in super-mini (SMV) and ultra-super-mini (USV) five-pin packages that occupy 75 and 87% less mounting area, respectively, than an SSOP. TTL LMOS parts have a typical propagation delay of 10 nsec and an input leakage current of 1 µA at 25°C. The SMV and USV versions of the TC7STxx cost $0.54 and $0.60, respectively (500). Toshiba America Electronic Components Inc, Irvine, CA. (800) 879-4963.

12-bit ADCs sample at 20 and 30 MHz. A family of high-speed 12-bit A/D converters serves a wide range of applications, including radar receivers and medical imaging. The family consists of the MN5925, with a 20-MHz sampling rate, and the MN5930 and MN6250, both with 30-MHz sampling rates. The MN5925 and MN5930 are monolithic devices housed in plastic DIPs. The MN6250, a mixed-signal multichip microcircuit based on the MN5930, combines a track-and-hold amplifier, reference, and timing circuitry in a 32-pin ceramic DIP. Devices operate over a temperature range of 0 to 70°C. The MN6250 is also specified for -55 to +125°C. Respective prices for the MN5925, 5930, and 6250 are $150, $201, and $335 (100). Micro Networks Corp, Worcester, MA. (508) 852-5400.

16-bit D/A converter is loop-powered. Intended for smart transmitters, the AD421 16-bit monolithic D/A converter sends 4 to 20 mA signals to a microcontroller to control a variety of digital-processing functions. The device has a zero-scale, 4-mA output current with ±0.1% offset error and a 20-mA, full-scale output current with ±0.2% gain error. Full-scale settling time to within ±0.1% is 5 msec. The AD421 includes a voltage regulator that provides 5, 3.3, or 3V outputs, as well as 1.25 and 2.5V references. It comes in 16-pin plastic DIP, SOIC, and SSOP versions and costs $6.95 (1000).Analog Devices Inc, Canton, MA. (617) 937-1428.

3.3V RS-485 transceiver is ESD-protected to 10 kV. The LTC1480 RS-485 transceiver operates from a 3.3V supply and typically requires 300 µA of supply current. The device combines this low-power operation with 10 kV of ESD protection. It is guaranteed to draw <500 µA with the driver disabled and <600 µA with the driver enabled (with no load). The LTC1480 meets RS-485 electrical requirements, including a wide common-mode range (-7 to +12V) that permits ±7V ground differences between devices on the bus. Packaging choices include eight-pin DIP and surface-mount versions. Prices start at $2.55 (1000). Linear Technology Corp, Milpitas, CA. (408) 432-1900.

Regulator IC converts 5V supply for 3V processors.Combining tight regulation and high efficiency for such processors as the Pentium and Pentium Pro, the LTC1430 switching regulator controller converts 5V to 3.3 or 2.5V or other processor core voltages at up to 15A of load current. Efficiency approaches 95% at high load currents, eliminating heat sinks commonly used with other regulator circuits. The device also guarantees that the output voltage is to within ±1% over line, load, and temperature variations. Packaging options include eight- and 16-lead plastic DIP and SOIC configurations. Prices start at $3.20 for eight-pin DIP versions (1000). Linear Technology Corp, Milpitas, CA. (408) 432-1900.

Current-mode switcher ICs offer undervoltage lockout. Consisting of eight members, a family of current-mode PWM switching regulators are differentiated by undervoltage lockout specifications, operating temperature range, and packaging. The CS-3842A, 2842A, 3844, and 2844 are rated for a start threshold of 16V typ and a minimum operating voltage of 10V typ. The CS-2843A, 3843A, 2845, and 3845 have a start threshold of 8.4V typ and a minimum operating voltage of 7.6V typ. All CS-38xx controllers operate over a temperature range of 0 to 70°C, and CS-28xx devices span -25 to +85°C. Packaging options include eight-pin wide-body DIPs, as well as eight- and 14-pin small-outline, narrow-body plastic DIPs. Prices start at $1.13 (1000). Cherry Semiconductor Corp, East Greenwich, RI. (401) 885-3600.

SRAM module serves as L2 cache for Pentium PCs.A 256-kbyte SRAM module, the MH32S64N-8, packs two 32k×32-bit synchronous pipeline burst SRAMs and one 32k×8-bit fast SRAM for tag functions into a 160-pin dual in-line memory module. You can use the memory module to provide L2 cache for Pentium-based PCs and also work with the Triton chip set. Samples of the MH32S64N-8 cost $69. Mitsubishi Electronics America Inc, Sunnyvale, CA. (408) 730-5900.