Datasheet

SN74VMEH22501
LVTTL-TO-ETL 8-BIT UNIVERSAL BUS TRANSCEIVER AND TWO 1-BIT BUS
TRANSCEIVERS WITH SPLIT LVTTL PORT, FEEDBACK PATH, AND 3-STATE OUTPUTS
SCES357A – JULY 2001 – REVISED SEPTEMBER 2001
6–5
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
functional description
The SN74VMEH22501 is a high-drive (±48 mA), 8-bit UBT transceiver containing D-type latches and D-type
flip-flops for data-path operation in transparent, latched, or flip-flop modes. Data transmission is true. The device
is uniquely partitioned as 8-bit UBT transceivers with two integrated 1-bit three-wire bus transceivers.
functional description for two 1-bit bus transceivers
The OEAB inputs control the activity of the 1B or 2B port. When OEAB is high, the B-port outputs are active.
When OEAB is low, the B-port outputs are disabled.
Separate 1A and 2A inputs and 1Y and 2Y outputs provide a feedback path for control and diagnostics
monitoring. The OEBY input controls the 1Y or 2Y outputs. When OEBY is low, the Y outputs are active. When
OEBY
is high, the Y outputs are disabled.
The OEBY
and OEAB inputs can be tied together to form a simple direction control where an input high yields
A data to B bus and an input low yields B data to Y bus.
1-BIT BUS TRANSCEIVER FUNCTION TABLE
INPUTS
OEAB OEBY
OUTPUT MODE
L H Z Isolation
H H A data to B bus
L L B data to Y bus
True driver
H L A data to B bus, B data to Y bus True driver with feedback path
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