HD74ALVCH16270 Datasheet, PDF (1/13 Pages) Hitachi Semiconductor – 12-bit to 24-bit Registered Bus Exchanger with 3-state Outputs

HD74ALVCH16270
12-bit to 24-bit Registered Bus Exchanger with 3-state Outputs
ADE-205-137 (Z)
Preliminary 1st. Edition
May 1996
Description
The HD74ALVCH16270 is used in applications where data must be transferred from a narrow high
speed bus to a wide lower frequency bus. 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
when the appropriate CLKEN inputs are low. The select (SEL) line 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 A to 1B path,
with a single storage register in the A to 2B path. Proper control of the CLKENA inputs allows two
sequential 12-bit words to be presented synchronously as a 24-bit word on the B port. Data flow is
controlled by the active low output enables (OEA, OEB). The control terminals are registered to
synchronize the bus direction changes with CLK. Active bus hold circuitry is provided to hold unused
or floating data inputs at a valid logic level.
Features
• V_CC = 2.3 V to 3.6 V
• Typical V_OL ground bounce < 0.8 V (@V_CC = 3.3 V, Ta = 25°C)
• Typical V_OH undershoot > 2.0 V (@V_CC = 3.3 V, Ta = 25°C)
• High output current ±24 mA (@V_CC = 3.0 V)
• Bus hold on data inputs eliminates the need for external pullup / pulldown resistors