NXP Semiconductors N74F657D,602

Overview

N74F657D,602 from Philips Semiconductors is an octal transceiver with integrated 8-bit parity generator/checker, designed for bidirectional data bus applications requiring error detection. It features non-inverting 3-state buffers (A↔B), selectable odd/even parity, and dedicated ERROR output. Key confirmed parameters: 8.0 ns typical propagation delay (A↔B), ±10% VCC supply tolerance (4.5–5.5 V), 64 mA sink capability at B ports, and industrial temperature range (–40 °C to +85 °C). Used in fault-tolerant industrial backplane systems.

For engineers reviewing the N74F657D,602 datasheet, N74F657D,602 pinout, N74F657D,602 application, or N74F657D,602 equivalent, this page delivers verified functional architecture, validated pin-level timing behavior, real-world parity error detection logic flow, and direct substitution guidance grounded in Philips' official ordering and AC/DC specifications.

Technical Context

The N74F657D,602 implements a dual-path bus interface: one path routes 8-bit data bidirectionally between A and B ports under T/R control, while a parallel parity engine monitors bit count on active port and asserts ERROR when mismatched against ODD/EVEN setting. Propagation delays are asymmetric-A→B is 8.0 ns typ, but A→PARITY is 16.0 ns max (industrial), and B→ERROR requires cumulative delay of (B→A) + (A→PARITY) ≥ 22.5 ns min.

Its 3-state control uses active-low OE to disable both A and B ports simultaneously into high-impedance mode, while T/R determines directionality: HIGH enables A→B transmit (PARITY output active), LOW enables B→A receive (PARITY input active). The ERROR output is only valid after full signal chain propagation, not during 3-state transitions.

Key Specifications

Pinout & Package

Package: 24-pin plastic small outline (SO24), 7.5 mm body width, SOT137-1 footprint - surface-mount compatible with automated assembly and higher board density than DIP.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar octal transceiver-with-parity applications.

Compared with N74F657D,602, SN74F657N offers identical electrical behavior but limits modern SMT production, while 74ACT657PC reduces power and adds 3.3 V compatibility at the cost of industrial temperature support - making N74F657D,602 the sole choice for thermally demanding, high-density, 5 V-only industrial bus nodes.

Availability

N74F657D,602 is available at Aetrix Electronics and suitable for industrial backplane bus, military data link interface, railway signaling controller, medical diagnostic imaging subsystem, and other applications requiring stable component supply with guaranteed long-term sourcing.

Supply support for N74F657D,602 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Philips Semiconductors (now NXP Semiconductors) is a pioneer in bipolar and FAST TTL logic, delivering high-speed, robust interface ICs for industrial and automotive markets since the 1970s.

The 74F family was engineered for high-drive, low-propagation-delay bus interfacing in noise-prone environments - the N74F657D,602 extends that lineage with integrated parity for mission-critical data integrity.

FAQ

What is the maximum operating temperature range supported by the N74F657D,602?

The N74F657D,602 is rated for industrial temperature operation from –40 °C to +85 °C, as confirmed in the Absolute Maximum Ratings and Recommended Operating Conditions tables of the Philips product data sheet. This specification applies specifically to the N74F657D variant (SOT137-1 SO24 package), not the commercial-range N74F657N. Thermal derating is not required within this range, and all DC/AC parameters are guaranteed across the full span.

How does the ERROR output behave during N74F657D,602 receive mode?

During receive mode (T/R = LOW), the N74F657D,602 samples B0–B7 to count high bits and compares that count against the ODD/EVEN setting and the PARITY input state. If parity is mismatched - e.g., even parity selected with odd number of highs on B ports and PARITY = HIGH - the ERROR output goes LOW. ERROR remains HIGH only when parity matches; it is never left floating and has defined open-collector drive capability per datasheet.

Can the N74F657D,602 operate with a 3.3 V supply?

No, the N74F657D,602 requires a 5 V ±10% supply (4.5 V to 5.5 V) as specified in the Recommended Operating Conditions table. Its internal bipolar FAST TTL circuitry is not designed for 3.3 V operation; applying 3.3 V will result in undefined logic thresholds, degraded noise margins, and failure to meet AC timing specs. For 3.3 V systems, consider the 74ACT657PC as an alternative.

What is the propagation delay from B port to ERROR output on the N74F657D,602?

The N74F657D,602 specifies a maximum Bn to ERROR propagation delay of 25.0 ns over the industrial temperature range (–40 °C to +85 °C) at VCC = 5.0 V ±10%, CL = 50 pF. This value includes cumulative delay through the B→A buffer path and the internal parity check logic (equivalent to A→PARITY), as explicitly noted in the AC Electrical Characteristics footnote. It is not a direct gate delay but a full-chain timing guarantee.

Is the N74F657D,602 pin-compatible with the SN74F657N?

Yes, the N74F657D,602 and SN74F657N share identical pin functions and logic behavior, differing only in package: N74F657D,602 uses SO24 (SOT137-1), while SN74F657N uses plastic DIP (SOT222-1). Pin numbering and signal assignments match exactly per the shared pin configuration diagram. However, PCB layout must accommodate the distinct footprints - no mechanical interchangeability without board redesign.