BUS LVDS LINE DRIVER ENABLES FULL-DUPLEX MULTIPOINT BUSES
SUNNYVALE, CA-September 10, 2001-Maxim Integrated Products introduces the latest member of the Maxim LVDS family—the MAX9129 quad bus, low-voltage differential signaling (BLVDS) line driver. The MAX9129 accepts four LVTTL/LVCMOS input levels and translates them to output levels of 250mV to 450mV (standard LVDS levels) into a 27Ω load (double terminated 54Ω differential backplane). The BLVDS outputs are designed to drive a heavily loaded, multipoint bus at up to 200Mbps, making the MAX9129 ideal for shared buses in communications infrastructure equipment. It is optimized for full-duplex communications, such as cards that simulatenously transmit data onto one bus while receiving data from another bus. Competing BLVDS products are transceivers, which share the BLVDS I/O pins between drivers and receivers, and therefore limit communications to half-duplex (e.g. a card can only transmit or receive data at any given time).
A controlled, 1ns minimum BLVDS output transition time (0 to 100%) reduces reflections and EMI resulting from stubs and imperfect termination. Power-on reset prevents glitching on the bus by ensuring that all outputs are disabled and high impedance during power up and power down. Two enable
inputs set the outputs to high impedance and put the device into a 10mW low-power state. The flow-through pinout simplifies PC board layout and reduces crosstalk by keeping the LVTTL/LVCMOS inputs and BLVDS outputs separated.
The MAX9129 operates from a single +3.3V supply and is specified for operation from -40°C to +85°C. It is available in 16-pin TSSOP and QFN (50% smaller than TSSOP) packages. Prices start at $3.50 for the MAX9129 (1000-up, FOB USA). Refer to the MAX9121 data sheet for a quad LVDS line receiver with flow-through pinout.
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