1 General description
The 74ALVCH16500 is a high-performance CMOS product. This device is an 18-bit
universal transceiver featuring non-inverting 3-state bus compatible outputs in both
send and receive directions. Data flow in each direction is controlled by output enable
(OEAB and OEBA), latch enable (LEAB and LEBA), and clock (CPAB and CPBA) 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 CPAB 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 HIGH-to-LOW transition
of CPAB. 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 CPBA.
The output enables are complimentary (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 pullup resistor and OEAB should be tied to GND
through a pulldown resistor; the minimum value of the resistor is determined by the
current-sinking/current-sourcing capability of the driver.
Active bus-hold circuitry is provided to hold unused or floating data inputs at a valid logic
level.
2 Features and benefits
• CMOS low power consumption
• MultiByte flow-through standard pin-out architecture
• Low inductance multiple VCC and GND pins for minimum noise and ground bounce
• Direct interface with TTL levels (2.7 V to 3.6 V)
• Bus hold on data inputs
• Output drive capability 50 Ω transmission lines at 85 °C
• Current drive ±24 mA at 3.0 V
• Complies with JEDEC standards:
– JESD8-5 (2.3 V to 2.7 V)
– JESD8B/JESD36 (2.7 V to 3.6 V)
• ESD protection:
– HBM ANSI/ESDA/JEDEC JS-001 exceeds 2000 V
– CDM JESD22-C101E exceeds 1000 V