HD74ALVCH16500 Datasheet | Hitachi Semiconductor

Description 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 bus data is stored in the latch flip flop on the high to low transition of CLKAB. Output enable OEAB is active high. When OEAB is high, the B port outputs are active. When OEAB is low, the B port 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 plementary (OEAB is active high, and OEBA is active low). Active bus hold circuitry is provided to hold unused or floating data inputs at a valid logic level. Features - VCC = 2.3 V to 3.6 V - Typical VOL ground bounce < 0.8 V (@VCC = 3.3 V, Ta = 25°C) - Typical VOH undershoot > 2.0 V (@VCC = 3.3 V, Ta = 25°C) - High output current ±24 m A (@V CC = 3.0 V) - Bus hold on data inputs eliminates the need for external pullup / pulldown resistors Function Table - 3 Inputs OEAB L H H H H H H LEAB X H H L L L L CLKAB X X X ↓ ↓ H L A X L H L H X X Z L H L H B0 B0 - 1 - 2 Output B H : High level L : Low level X : Immaterial Z : High impedance ↓ : High to low transition Notes: 1. Output level before the indicated steady state input conditions were established. 2. Output level before the indicated steady state input conditions were established, provided that CLKAB was low before LEAB went low. 3. A to B data flow is show; B to A flow is similar but uses OEBA, LEBA, and CLKBA . Pin Arrangement OEAB 1 LEAB 2 A1 3 GND 4 A2 5 A3 6 VCC 7 A4 8 A5 9 A6 10 GND 11 A7 12 A8 13 A9 14 A10 15 A11 16 A12 17 GND 18 A13 19 A14 20 A15 21 VCC 22 A16 23 A17 24 GND 25 A18 26 OEBA 27 LEBA 28 56 GND 55 CLKAB 54 B1 53 GND 52 B2 51 B3 50 VCC 49 B4 48 B5 47 B6 46 GND 45 B7 44 B8 43 B9 42...