1
PS8133A
01/31/00
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PI74ALVCH16501
18-Bit Universal Bus Transceiver
With 3-State Outputs
Logic Block Diagram
Product Description
Pericom Semiconductor’s PI74ALVCH series of logic circuits are
produced in the Company’s advanced 0.5 micron CMOS technology,
achieving industry leading speed.
The 18-bit PI74ALVCH16501 univeral bus transceiver is designed
for 2.3V to 3.6V VCC operation.
Data flow in each direction is controlled by Output Enable (OEAB
and OEBA), Latched 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-bus 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, OEBA should be tied to VCC through a pull-up resistor and
OEAB should be tied to GND through a pulldown resistor; the
minimum value of the resistor is determined by the current-sinking
capability of the driver.
Active bus-hold circuitry is provided to hold unused or floating
data inputs at a valid logic level.
Product Features
PI74ALVCH16501 is designed for low voltage operation
VCC =2.3Vto3.6V
Hysteresis on all inputs
Typical VOLP (Output Ground Bounce)
< 0.8V at VCC = 3.3V, TA = 25°C
Typical VOHV (Output VOH Undershoot)
< 2.0V at VCC = 3.3V, TA = 25°C
Bus Hold retains last active bus state during 3-STATE
eliminating the need for external pullup resistors
Industrial operation at –40°C to +85°C
Packages available:
– 48-pin 240 mil wide plastic TSSOP (A)
– 48-pin 300 mil wide plastic SSOP (V)