Focus on Logic Ideas

New TI logic makes good design sense

New AHC Widebus products provide an effortless migration path from HCMOS. Other introductions provide advanced end-equipment solutions.

A variety of newly introduced logic products and product families from TI provide designers with advanced solutions for a wide range of end equipments. Among the new offerings are the industry's first advanced high-speed CMOS (AHC) Widebus™ 16-bit bus interfaces, which have the same or better features as HCMOS with no penalty in ease of design or price. Other offerings include a low-power, high-drive GTL universal bus transceiver (UBT) for heavily loaded telecom and networking back-planes; the industry's first LVTTL-to-SSTL universal bus driver for addressing SDRAMs in high-performance memory subsystems; and the first 3.3-V digitally controlled bus switches on the market.

AHC Widebus: reliable, effortless migration

The new AHC Widebus devices complement TI's established line of AHC gates, octals and Microgate logic, providing an industry-leading array of AHC logic ICs with greater performance and less power consumption than standard high-speed CMOS (HCMOS), but without an increase in signal noise or price. The introduction of Widebus components provides new AHC options that can reduce component counts, board space and overall system cost.

With low propagation delay and half the static power consumption of HCMOS, AHC Widebus devices allow designers to increase system speeds while lowering overall power requirements. Additionally, AHC provides the same low noise found in HCMOS. Multiple power and ground pins on AHC Widebus devices can actually lower noise by 20 percent over two equivalent HCMOS octal devices, providing greater signal integrity throughout the system.

"With AHC Widebus, the default logic choice for many applications has become faster, less power-hungry and capable of lowering component counts," said Ed Agis, strategic marketing manager for TI logic products. "Designers can not only gain performance but also future-proof their designs for the time when HCMOS is no longer readily available."

GTL1655 Universal Bus Transceiver (UBT)

The GTL1655 UBT combines high drive of up to 100 mA with the low power consumption and high speed of Gunning Transceiver Logic (GTL) for optimized use in heavily loaded backplanes. The new UBT allows designers to substitute the low-power GTL switching standard for Backplane Transceiver Logic (BTL) in systems which require high-speed backplane communications, such as telecom and networking equipments.

The 16-bit live-insertable device translates signals between 3.3-V transistor-to-transistor logic (LVTTL) levels and 1.2-V GTL or 1.5-V GTL+ levels. Features that make the 1655 attractive for high-speed systems include 160-MHz operation, output edge rate control (OEC™) to minimize high-frequency noise, bus hold for reduced power requirements and cost, and capabilities for device and signal protection during live card insertion.

SSTL16837 Universal Bus Driver

The SSTL16837 is the industry's first device for driving 3.3-V LVTTL address signals from a memory controller to SDRAMs using Stub Series Terminated Logic (SSTL) technology. In designs operating at greater than 75 MHz, the 16837 provides fast address signaling with minimal propagation delay. Targeted users of the device include workstations and servers, with eventual migration to PCs.

CBTLV Digitally Controlled Bus Switches

The low-voltage crossbar technology (CBTLV) is the industry's first family of digitally controlled switches to combine 3.3-V operation with the switching benefits of CBT. As notebook PCs and other portable systems migrate to low-voltage operation, CBTLV switches will become increasingly valuable for bus isolation and hot-docking support. Designs will benefit from simplification, reduced power requirements and support for the elimination of the 5-V power supply altogether.

Packaging and availability

AHC Widebus components are sampling now, with volume production planned for 4Q97. AHC Widebus pricing is expected to be the same as that for equivalent HCMOS devices, in the $.55 to $.65 range in quantities of 1,000. Options include Widebus thin small outline packages (TSSOPs) and thin very small outline packages (TVSOPs).

The GTL1655 UBT is sampling now, with volume production planned for 4Q97. Planned pricing is $10.33 in quantities of 1,000. TSSOPs and ceramic quad flatpacks (CQFPs) are planned options.

The SSTL16837 universal bus driver is available now in a 64-pin TSSOP. Suggested pricing is $6 in quantities of 1,000.

CBTLV switches are sampling now, with volume production dates planned throughout 2H97. A wide variety of packaging options are planned. Planned pricing is in the range of $.83 to $1.25 for octal switches and $2.08 to $2.92 for 16-bit Widebus switches, all in quantities of 1,000.

Widebus is a trademark of Texas Instruments, Incorporated.