Equivalent Series Resistor on 3A Ports and Y OutputsMicroStar is a trademark of Texas Instruments.
(1) VME320 is a patented backplane construction by Arizona Digital, Inc.
The SN74VMEH22501 8-bit universal bus transceiver has two integral 1-bit three-wire bus transceivers and is designed for 3.3-V VCC operation with 5-V tolerant inputs. The UBT™ transceiver allows transparent, latched, and flip-flop modes of data transfer, and the separate LVTTL input and outputs on the bus transceivers provide a feedback path for control and diagnostics monitoring. This device provides a high-speed interface between cards operating at LVTTL logic levels and VME64, VME64x, or VME320(1) backplane topologies.
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 VCC ± 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 Ioff, power-up 3-state, and BIAS VCC. The Ioff 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 VCC 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 VCC 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 VCC 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.
| Type | Title | Date | ||
|---|---|---|---|---|
| * | Data sheet | SN74VMEH22501 datasheet (Rev. F) | 23 Feb 2010 | |
| Selection guide | Logic Guide (Rev. AB) | 12 Jun 2017 | ||
| Application note | Understanding and Interpreting Standard-Logic Data Sheets (Rev. C) | 02 Dec 2015 | ||
| User guide | LOGIC Pocket Data Book (Rev. B) | 16 Jan 2007 | ||
| Application note | Semiconductor Packing Material Electrostatic Discharge (ESD) Protection | 08 Jul 2004 | ||
| Application note | SN74VMEH22501 Universal Bus Transceiver for the VMEbus Backplane | 14 May 2003 | ||
| More literature | SN74VMEH22501 Application Clip | 04 Mar 2003 | ||
| Application note | VMEH22501 in 2eSST and Conventional VME Backplane Applications | 07 Oct 2002 | ||
| Application note | Power-Up 3-State (PU3S) Circuits in TI Standard Logic Devices | 10 May 2002 |
For additional terms or required resources, click any title below to view the detail page where available.
| Package | Pins | CAD symbols, footprints & 3D models |
|---|---|---|
| TSSOP (DGG) | 48 | Ultra Librarian |
| TVSOP (DGV) | 48 | Ultra Librarian |
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