Design Considerations

Backward compatibility — The VMEH22501/A improves the performance up to 8X of the VMEbus™ without making changes to existing hardware.

Standard Specification — The VMEH22501/A are referenced by the 2eSST VITA 1.5 spec as a device that provides excellent signaling at 40-Mbps data rate.

Increased Noise Immunity — The ±50-mV input threshold allows the VMEH22501/A to provide clean signaling under harsh environments.

Full Live Insertion—This device is fully specified for live-insertion applications using IOFF, power-up 3-state and BIAS VCC.

Speed/Signal Integrity—High-speed backplane operation is a direct result of the improved OEC circuitry that has been tested on the standard VME backplane. Furthermore, signal integrity is not compromised with higher speed operation.

VME 41

Technical Information

TI’s SN74VMEH22501/A are specifically designed for the VMEbus technology. The device is an 8-bit universal bus transceiver (UBT) with two bus transceivers. It provides incident switching on the 21-slot VMEbus backplane, thus providing data signaling rates of up to 40 Mbps-—an 8X improvement over the VME64 standard.

Highlights

• Ability to transmit data on the VMEbus

up to 2eSST protocol speed is an

improvement over VME64.

• Incident wave switching allows for higher

VME Parametric Table

 

 

Parameter Name

SN74VMEH22501

SN74VMEH2501A

Voltage Nodes (V)

3.3

3.3

VCC Range (V)

3.15 to 3.45

3.15 to 3.45

Input Level

LVTTL

LVTTL

Output Level

LVTTL

LVTTL

Output Drive (mA)

–48/64

–48/64

No. of Outputs

10

10

Logic

True

True

Static Current (mA)

30

30

tpd max (ns)

8.9

8.9

TA

0° C to 85° C

–40° C to 85° C

Resources For a complete list of resources (evaluation modules, data sheets and application notes), visit interface.ti.com

Literature Number

Description

Application Notes

 

SCEA028

VMEH22501 in 2eSST and Conventional VME Backplane Applications

Other Literature

 

SCYB009

VME Application Clip

performance on the VMEbus compared to

conventional logic that depends on

reflective wave switching.

Texas Instruments 4Q 2006

Interface Selection Guide

Page 41
Image 41
Texas Instruments 4Q 2006 manual Vme, Highlights