SN54GTL16923, SN74GTL16923

18-BIT LVTTL-TO-GTL/GTL+ BUS TRANSCEIVERS

SCBS674E – AUGUST 1996 – REVISED NOVEMBER 1999

1

POST OFFICE BOX 655303

Widebus

™ Family

Enable

and LVTTL Logic Levels

All Ports (5-V Input/Output Voltages With

Operation

Need for External Pullup/Pulldown

Resistors on A Port

Minimizes High-Speed Switching Noise

– 2000-V Human-Body Model (A114-A)

– 200-V Machine Model (A115-A)

– 1000-V Charged-Device Model (C101)

JESD 17

Shrink Small-Outline (DGG) and Ceramic

Quad Flat (HV) Packages

description

The ’GTL16923 devices are 18-bit registered bus transceivers that provide LVTTL-to-GTL/GTL+ and

GTL/GTL+-to-LVTTL signal-level translation. They are partitioned as two 9-bit transceivers with individual

output-enable controls and contain D-type flip-flops for temporary storage of data flowing in either direction. The

devices provide an interface between cards operating at LVTTL logic levels and a backplane operating at

GTL/GTL+ signal levels. Higher-speed operation is a direct result of the reduced output swing (

<1 V), reduced

input threshold levels, and output edge control (OEC

™).

of the Gunning transceiver logic (GTL) JEDEC standard JESD 8-3. The B port normally operates at GTL or

GTL+ signal levels, while the A-port and control inputs are compatible with LVTTL logic levels. All inputs can

is the reference input voltage for the B port.

Data flow in each direction is controlled by the output-enable (OEAB and OEBA) and clock (CLKAB and CLKBA)

inputs. The clock-enable (CEAB and CEBA) inputs are used to enable or disable the clock for all 18 bits at a

time. However, OEAB and OEBA are designed to control each 9-bit transceiver independently, which makes

the device more versatile.

For A-to-B data flow, the device operates on the low-to-high transition of CLKAB if CEAB is low. When OEAB

is low, the outputs are active. When OEAB is high, the outputs are in the high-impedance state. Data flow for

B to A is similar to that of A to B but uses OEBA, CLKBA, and CEBA.

outputs, preventing damaging current backflow through the devices when they are powered down.

Active bus-hold circuitry holds unused or undriven LVTTL inputs at a valid logic state. Use of pullup or pulldown

resistors with the bus-hold circuitry is not recommended.

resistor; the minimum value of the resistor is determined by the current-sinking capability of the driver.

The SN54GTL16923 is characterized for operation over the full military temperature range of –55

°C to 125°C.

The SN74GTL16923 is characterized for operation from –40

°C to 85°C.

Copyright

© 1999, Texas Instruments Incorporated

UNLESS OTHERWISE NOTED this document contains PRODUCTION

DATA information current as of publication date. Products conform to

specifications per the terms of Texas Instruments standard warranty.

Production processing does not necessarily include testing of all

parameters.

Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of

Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.

Widebus and OEC are trademarks of Texas Instruments Incorporated.