Dual Line Driver/Receiver Combines High Current Output with Low Signal Distortion
New Device is Integral to TI's Innovative DSP-based ADSL Chipset Solution
DALLAS (Feb. 2, 1998) -- A new dual line driver/receiver device that provides the high output current often needed to drive data over standard telephone lines with practically negligible signal distortion was announced today by Texas Instruments. This innovative, high-speed 200 MHz device can be used to design a wide range of communication systems, but it is particularly well suited to ADSL (asymmetrical digital subscriber line) applications including central office switches and multiplexers.
The device is part of TI's newly introduced ADSL chipset, which features an advanced programmable DSP, a digital interface and an analog front end.
"The dire need for higher data communication speeds over today's telephone lines is abundantly clear. All you have to do is get on the Internet to realize this," said Jim Quarfoot, a senior technical staff member for TI's mixed-signal products. "This dual line driver/receiver can be used in high-speed data communication systems and in applications like ADSL which are being developed to effectively get the most out of our installed infrastructure of copper telephone lines. In developing this device, we were able to leverage our long-term mixed-signal and analog experience with data transmission technologies, including transceivers, 1394, UARTs, codecs and DSP solutions."
The new line driver/receiver, which has been designated as the THS6002, features four amplifiers. Two amplifiers are well suited to performing the task of line drivers, while the remaining two amplifiers have the performance characteristics of receivers. All four amplifiers have a very high slew rate of 1,000 volts per microsecond, assuring very low levels of total harmonic distortion (THD). A high slew rate minimizes distortion by allowing the output of a line driver/receiver to follow more closely the rise and fall of the input signal. The THS6002's exceptional output drive of more than 400 milli-amps is ideal for driving low impedance lines the two to three miles required by the telephone network's local loop.
Crosstalk, which is electrical noise or extraneous signals caused by AC or pulse-type signals in adjacent wires, is minimized in the system by the THS6002 because each of the four amplifiers on the device has its own separate power supply pin. When two or more amplifiers share a single power pin or when power pins are adjacent to each other, crosstalk is often increased in the system. Additionally, the THS6002's drivers/receivers can be configured differentially to further reduce noise levels in the system.
To assure that heat generated by the high current levels passing through the THS6002 is dissipated efficiently, the device comes in TI's exclusive thermally enhanced, small outline integrated circuit (SOIC) PowerPAD™ package. PowerPAD enables true surface mount packages to be used in designs previously limited to bulky DDPAK and TO-220 packages. The thermal pad on the underside of the PowerPAD package is in direct contact with the die to effectively dissipate heat away from the device.
TI's advanced high-voltage complementary bipolar (HVBiCom) process assures the THS6002 has very low total harmonic distortion. HVBiCom produces devices with full dielectric isolation rather than the simple junction isolation of other bipolar processes. With full dielectric isolation, semiconductors are capable of higher bandwidth performance, smaller die sizes and faster slew rates, which ensure low signal distortion.
Pricing and availability
The THS6002 comes in a 20-pin thermally enhanced SOIC package. Engineering samples are available from Texas Instruments and its authorized distributors. Production volumes are expected to be available during the first half of 1998. Suggested resale pricing in quantities of 1,000 is anticipated to be $5.67.
More information regarding TI's high-speed amplifier products and the PowerPAD package is available on the World Wide Web at 
http://www.ti.com/sc/opamp.
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