74ACT1284SCX

Overview

The onsemi 74ACT1284SCX is an IEEE 1284 transceiver housed in a 20-lead SOIC package. It operates within a supply voltage range of 4.5V to 5.5V and supports temperatures from -40°C to +85°C. The device integrates four non-inverting bidirectional buffers and three non-inverting buffers with open-drain outputs. It features high drive capability on the B ports, capable of sourcing 14 mA, while A ports provide standard 4 mA totem pole outputs. The component includes TTL-compatible inputs and guarantees minimum ESD protection of 4000V.

Feature Summary

• Supports IEEE P1284 Level 1 and Level 2 signaling standards for bidirectional parallel communications
• Features high drive capability on B ports with source/sink capacity of 14 mA
• Includes guaranteed 4000V minimum ESD protection
• Provides TTL-compatible inputs for interface compatibility

Applications

• Extended Capabilities Port (ECP) mode for bi-directional parallel peripherals
• Bidirectional parallel communications between personal computers and printing peripherals
• IEEE 1284 compliant data transfer interfaces

Procurement Notes

Verify that the specific ordering code matches the required package type, as the 74ACT1284 series is available in multiple formats including SOIC, SSOP, and TSSOP. Confirm that the 'X' suffix indicates tape and reel packaging if automated assembly is required. Ensure the design accounts for the recommended operating conditions, specifically the 4.7V to 5.5V supply voltage range, to maintain signal integrity and performance specifications.

Selection Notes

Select this component when designing systems requiring compliance with IEEE 1284 standards for bidirectional data transfer. The choice is driven by the need for high drive current on the B port side, which simplifies load driving compared to standard logic families. Consider the 20-lead SOIC package dimensions for PCB layout constraints. Verify that the input hysteresis and propagation delay characteristics meet the timing requirements of the target peripheral interface.

Part Context

This device belongs to the 74ACT logic family, characterized by CMOS technology with TTL-compatible inputs. It serves as a specialized interface solution for parallel port applications, bridging the gap between standard logic levels and the higher drive requirements of peripheral devices. The inclusion of open-drain outputs on specific pins allows for flexible configuration in multi-drop or shared bus environments typical of legacy parallel communication protocols.

Replacement Considerations

Check for equivalent transceivers from other manufacturers that support the same IEEE 1284 protocol. Verify pin-to-pin compatibility if substituting packages such as SSOP or TSSOP variants. Ensure that alternative components offer comparable high-drive capabilities and ESD protection ratings to maintain system reliability.