Datasheet

SN74VMEH22501A
SCES3620A –DECEMBER 2004–REVISED FEBRUARY 2010 www.ti.com
DESCRIPTION/ORDERING INFORMATION (CONTINUED)
High-speed backplane operation is a direct result of the improved OEC™ circuitry and high drive that has been
designed and tested into the VME64x backplane model. The B-port I/Os are optimized for driving large capacitive
loads and include pseudo-ETL input thresholds (½ V
CC
± 50 mV) for increased noise immunity. These
specifications support the 2eVME protocols in VME64x (ANSI/VITA 1.1) and 2eSST protocols in VITA 1.5. With
proper design of a 21-slot VME system, a designer can achieve 320-Mbyte transfer rates on linear backplanes
and, possibly, 1-Gbyte transfer rates on the VME320 backplane.
All inputs and outputs are 5-V tolerant and are compatible with TTL and 5-V CMOS inputs.
Active bus-hold circuitry holds unused or undriven 3A-port inputs at a valid logic state. Bus-hold circuitry is not
provided on 1A or 2A inputs, any B-port input, or any control input. Use of pullup or pulldown resistors with the
bus-hold circuitry is not recommended.
This device is fully specified for live-insertion applications using I
off
, power-up 3-state, and BIAS V
CC
. The I
off
circuitry prevents damaging current to backflow through the device when it is powered off/on. The power-up
3-state circuitry places the outputs in the high-impedance state during power up and power down, which prevents
driver conflict. The BIAS V
CC
circuitry precharges and preconditions the B-port input/output connections,
preventing disturbance of active data on the backplane during card insertion or removal, and permits true
live-insertion capability.
When V
CC
is between 0 and 1.5 V, the device is in the high-impedance state during power up or power down.
However, to ensure the high-impedance state above 1.5 V, output-enable (OE and OEBY) inputs should be tied
to V
CC
through a pullup resistor and output-enable (OEAB) inputs should be tied to GND through a pulldown
resistor; the minimum value of the resistor is determined by the drive capability of the device connected to this
input.
ORDERING INFORMATION
T
A
PACKAGE
(1)
ORDERABLE PART NUMBER TOP-SIDE MARKING
BGA MicroStar™
Tape and reel SN74VMEH22501AZQLR VK501A
Junior – ZQL
TSSOP – DGG Tape and reel SN74VMEH22501ADGGR VMEH22501A
–40°C to 85°C
TVSOP – DGV Tape and reel SN74VMEH22501ADGVR VK501A
VFBGA – GQL Tape and reel SN74VMEH22501AGQLR VK501A
(1) Package drawings, thermal data, and symbolization are available at www.ti.com/sc/packaging.
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Product Folder Link(s): SN74VMEH22501A