GENERAL DESCRIPTION
The ST16C554/554D (554) is a quad Universal Asynchronous Receiver and Transmitter (UART) with 16 bytes of transmit and receive FIFOs, selectable receive FIFO trigger levels and data rates of up to 1.5 Mbps. Each UART has a set of registers that provide the user with operating status and control, receiver error indications, and modem serial interface controls. An internal loopback capability allows onboard diagnostics. The 554 is available in a 64-pin LQFP and a 68-pin PLCC package. The 64-pin package only offers the 16 mode interface, but the 68-pin package offers an additional 68 mode interface which allows easy integration with Motorola processors. The ST16C554CQ64 (64-pin) offers three state interrupt output while the ST16C554DCQ64 provides continuous interrupt output. The 554 combines the package interface modes of the 16C554 and 68C554 on a single integrated chip.

FEATURES
 • Pin-to-pin compatible with the industry standard ST16C454, ST68C454, ST68C554, TI’s TL16C554A and Philips’ SC16C554B
 • Intel or Motorola Data Bus Interface select
 • Four independent UART channels
    ■ Register Set Compatible to 16C550
    ■ Data rates of up to 1.5 Mbps at 5 V
    ■ Data rates of up to 500 Kbps at 3.3V
    ■ 16 byte Transmit FIFO
    ■ 16 byte Receive FIFO with error tags
    ■ 4 Selectable RX FIFO Trigger Levels
    ■ Full modem interface
 • 2.97V to 5.5V supply operation
 • Crystal oscillator or external clock input

APPLICATIONS
 • Portable Appliances
 • Telecommunication Network Routers
 • Ethernet Network Routers
 • Cellular Data Devices
 • Factory Automation and Process Controls