Members of the Texas Instruments
WidebusE Family
State-of-the-Art EPIC-IIBE BiCMOS Design
Significantly Reduces Power Dissipation
UBT E (Universal Bus Transceiver)
Combines D-Type Latches and D-Type
Flip-Flops for Operation in Transparent,
Latched, or Clocked Mode
ESD Protection Exceeds 2000 V Per
MIL-STD-883, Method 3015; Exceeds 200 V
Using Machine Model (C = 200 pF, R = 0)
Latch-Up Performance Exceeds 500 mA Per
JEDEC Standard JESD-17
Typical VOLP (Output Ground Bounce)
< 0.8 V at VCC = 5 V, TA = 25°C
Flow-Through Architecture Optimizes PCB
Layout
Package Options Include Plastic 300-mil
Shrink Small-Outline (DL) and Thin Shrink
Small-Outline (DGG) Packages and 380-mil
Fine-Pitch Ceramic Flat (WD) Package
Using 25-mil Center-to-Center Spacings

description
These 18-bit universal bus transceivers consist of
storage elements that can operate either as
D-type latches or D-type flip-flops to allow data
flow in transparent or clocked modes.
Data flow in each direction is controlled by
output-enable (OEAB and OEBA), latch-enable
(LEAB and LEBA), and clock (CLKAB and
CLKBA) inputs. For A-to-B data flow, the device
operates in the transparent mode when LEAB is
high. When LEAB is low, the A data is latched if
CLKAB is held at a high or low logic level. If LEAB
is low, the A data is stored in the latch/flip-flop on
the low-to-high transition of CLKAB. When OEAB
is high, the outputs are active. When OEAB is low,
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, LEBA, and CLKBA. The output enables are
complementary (OEAB is active high and OEBA is active low).
To ensure the high-impedance state during power up or power down, OE should be tied to GND through a
pulldown resistor and OE should be tied to VCC through a pullup resistor; the minimum value of the resistor is
determined by the current-sourcing/current-sinking capability of the driver.