SCES094 - FEBRUARY 1997
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of TexasInstruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
Widebus and EPIC are trademarks of Texas Instruments Incorporated.
The SN74ALVCHG162282 is an 18-bit to 36-bit registered bus exchanger. This device is intended for use in applications where data must be transferred from a narrow high-speed bus to a wide lower-frequency bus. It is designed specifically for low-voltage (3.3 V) VCC operation.
The device provides synchronous data exchange between the two
ports. Data is stored in the internal registers on the low-to-high
transition of the clock (CLK) input. For data transfer in the B-to-A
direction, the select (
)
input selects 1B or 2B data for the A outputs.
For data transfer in the A-to-B direction, a two-stage pipeline is
provided in the 1B path, with a single storage register in the 2B
path. Data flow is controlled by the active-low output-enable (
) and direction-control (DIR)
input. DIR is registered to synchronize the bus direction changes
with the clock.
The A-port N-channel output transistors are sized at 450
m and the P-channel output
transistors are sized at 700
m.
All A-port outputs have 50-
damping resistors. The B-port N-channel output transistors are sized
at 225
m, and the
P-channel output transistors are sized at 560
m. All B-port outputs have 20-
damping resistors.
Active bus-hold circuitry is provided to hold unused or floating data inputs at a valid logic level.
The switching characteristics are based on a 25-pF (A port) and 80-pF (B port) load, but are tested with the standard 50-pF load.
The SN74ALVCHG162282 is characterized for operation from 0°C to 70°C.