TI Home > News Releases

News Releases

National Semiconductor Introduces TFT LCD Chip Set Based on Reduced Swing Differential Signaling (RSDS) Technology

New LCD Panel Timing Controller and Column Driver Use RSDS Digital Interface to Reduce EMI-Radiated Noise and Lower Power Consumption

Nov 17, 1997

November 17, 1997 - National Semiconductor Corporation® today introduced a chip set for SVGA/XGA TFT LCD panels at Fall Comdex '97. The new video IC's incorporate National's power-saving, low-noise Reduced Swing Differential Signal (RSDS) digital interface technology. RSDS is a derivative of the Low Voltage Differential Signal (LVDS) technology used in National's FPD-Link interface chip set - a widely used standard for notebook motherboard to flat panel display. National's new TFT LCD chip set consists of the FPD63310 universal interface SVGA/XGA panel timing controller and the LMC7532 column driver.

"These devices are the first of a kind," said Masaya Higikigawa, Corporate Director and General Manager of the LCD Group at Sharp Corporation. "With the RSDS bus interface, they are designed to work at new lows with regards to both power consumption and EMI-radiated noise. Together, they're key to the upgrade migration toward larger and higher resolution TFT LCD panels. With RSDS technology, all the pieces are now in place to enable the next generation of flat panel displays," he added.

The bus interface between the panel timing controller and column drivers has historically been a major source of EMI and power dissipation inside the panel, due to the common use of TTL level signaling on this bus. However, with National's FPD63310 timing controller and LMC7532 column drivers, RSDS interface signals replace TTL signals on the bus. By reducing the signal swing level and implementing a differential signaling technique, RSDS results in significant reductions in power consumption and EMI levels (versus the TTL bus interface).

"Lowering power and EMI is key to portable applications where TFT LCDs are commonly used for the purpose of extending battery life, reducing weight and thickness, and enabling quicker time to market, while ultimately saving cost," noted Tammy Michel, Marketing Manager for display ICs at National Semiconductor. "We are focused on developing and delivering silicon solutions that address tough customer problems. This chip set does just that."

The FPD63310 timing controller provides the data buffering and control signal generation for the flat panel display, and with integrated RSDS transmitters, drives the LMC7532 column drivers at 130Mb/s with a 65MHz clock. Operating at a 65MHz clock frequency enables a single-pixel system interface, eliminating one of the two pixel busses typically required in TTL-type panels. A narrow 9-pair differential column driver bus minimizes the width of the PCB. In addition, the timing controller is highly programmable, allowing the user to adjust for optimal display quality in real-time by modifying the panel’s timing signals. This programmability enables quicker time-to-market than the gate array approach commonly used today, which takes many weeks for modification. This CMOS device operates from a 3.3V supply.

The LMC7532 column driver receives RSDS data through an integrated RSDS receiver, and converts the 18-bit digital data into analog voltage for the selectable 300 or 309 columns found in SVGA or XGA systems. Use of a switched reference type DAC gives high accuracy with low reference current requirements. The IC consists of an RSDS receiver and demux, registers, latches and output drivers. Typical accuracy is +/-5mV.

Price and Availability
Both the LMC7532 column driver and the FPD63310 timing controller are currently available from National Semiconductor. The LMC7532CT is housed in a TCP (Tape Chip Package) with dual leads that connect to the panel PCB and glass. It is priced at $6.50 in 10,000-unit quantities. The FPD63310 is offered in a 100-pin thin quad flatpak (TQFP) and is priced at $8.50 in 1000-unit lots.

National Semiconductor Corporation, a Fortune 500 company, produces system on a chip silicon solutions for the information highway, based on its leadership in analog and mixed signal technologies. National is headquartered in Santa Clara, California, and focuses on the communications, personal systems and consumer markets. National has annual sales of approximately $2.5 billion and 12,700 employees worldwide. Additional company and product information is available on the World Wide Web at www.national.com.