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Home > Products > Integrated Circuits (ICs) > Logic > FIFOs Memory

NXP Semiconductors 74HCT7403D,518

Name: 74HCT7403D,518
Brand: NXP Semiconductors
SKU: 74HCT7403D,518
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: 74HCT7403D,518

Manufacturer:: NXP Semiconductors

Category:: FIFOs Memory

Package:: 16-SOIC (0.295", 7.50mm Width)

Datasheet:: 74HCT7403D,518.pdf

Description:: IC FIFO ASYNC/SYNC 64X4 16SO

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Product details

Overview

74HCT7403D,518 from NXP Semiconductors is a 4-bit × 64-word asynchronous/synchronous FIFO register with 3-state outputs, TTL-compatible inputs, and guaranteed 15 MHz data rate (30 MHz typical in burst mode). It features DIR/DOR status flags, master reset (MR), output enable (OE), and separate SI/SO controls for independent read/write operations - deployed in high-speed disc/tape controllers and communications buffers.

For engineers reviewing the 74HCT7403D,518 datasheet, 74HCT7403D,518 pinout, 74HCT7403D,518 application, or 74HCT7403D,518 equivalent, this device delivers deterministic latency control via flag-driven handshaking, supports parallel/serial expansion for word/bit scaling, and operates across −40 °C to +125 °C in SO16 package with JEDEC JESD7A compliance.

Technical Context

This FIFO implements dual-stage shift architecture: data enters via SI into an input stage (flagged by DIR), then ripples through to output stage (flagged by DOR) upon SO activation. DIR = HIGH indicates readiness to accept data; DOR = HIGH signals valid output available at Q0–Q3.

It supports synchronous operation (SI/SO edge-triggered transfers) and asynchronous handshaking (DIR/DOR flag coordination), with propagation delays as low as 7 ns (DOR→Qn, VCC = 4.5 V) and recovery time of 18 ns (MR→SI). TTL-level inputs ensure compatibility with legacy logic families without level-shifting.

Key Specifications

Parameter	Value and Actual Design Meaning
Memory depth	64 words × 4 bits - provides 256-bit buffer capacity for burst-mode data alignment between mismatched clock domains.
Max data rate	30 MHz typical (burst mode, no flag monitoring) - enables sub-34 ns cycle time for high-throughput streaming applications.
Supply voltage	4.5 V to 5.5 V - matches standard 5 V TTL systems and ensures robust noise margin with VIH ≥ 2.0 V, VIL ≤ 0.8 V.
Propagation delay	7 ns (DOR→Qn, VCC = 4.5 V) - guarantees tight timing control for real-time output availability after flag assertion.
Operating temperature	−40 °C to +125 °C - qualified for automotive under-hood and industrial control environments requiring extended thermal stability.
Output drive	3-state, ±8 mA (VOH/VOL @ VCC = 4.5 V) - supports bus sharing and multi-drop configurations without contention.
ESD protection	HBM > 2000 V, MM > 200 V - meets IEC 61000-4-2 Level 3 for reliable handling in automated assembly lines.

Pinout & Package

74HCT7403D,518 is housed in a plastic small outline package (SO16), 16-pin, 3.9 mm body width (SOT109-1), surface-mount compatible with IPC-7351B footprint standards.

Pin/Terminal	Circuit Role	Design Meaning
1 (OE)	Output enable input	Active LOW control enabling/disabling Q0–Q3 outputs - allows shared-bus arbitration without external logic.
2 (DIR)	Data-in-ready flag	Open-drain HIGH when FIFO input stage is empty and ready to accept new data; LOW when full or busy.
3 (SI)	Shift-in input	Active HIGH edge triggers parallel load of D0–D3 into input stage; initiates ripple-through on subsequent LOW transition.
4–7 (D0–D3)	Parallel data inputs	4-bit wide synchronous data path accepting byte-aligned input during SI assertion - supports bit-width expansion via AND-gated DIR/DOR.
8 (GND)	Ground reference	0 V return for all internal logic and I/O - requires low-inductance connection to minimize ground bounce in high-speed switching.
9 (MR)	Master-reset input	Asynchronous active LOW clears FIFO contents and resets DIR/DOR flags - used for system initialization or error recovery.
10–13 (Q0–Q3)	Data outputs	3-state, TTL-compatible outputs reflecting current word in output stage - enabled only when OE = LOW and DOR = HIGH.
14 (DOR)	Data-out-ready flag	Open-drain HIGH when valid data resides in output stage and is ready for readout; LOW during transfer or when FIFO is empty.
15 (SO)	Shift-out input	Active LOW edge unloads current output word and triggers "bubble-up" of next word - enables pipelined readout without CPU polling.
16 (VCC)	Supply voltage	+4.5 V to +5.5 V power rail - decoupling capacitor (100 nF ceramic) required within 5 mm of pin for stable high-frequency operation.

Key Features

Feature	Design Value
Synchronous/asynchronous operation	Supports both clock-synchronized transfers (SI/SO edges) and flag-based handshaking (DIR/DOR) - eliminates need for external state machines in mixed-timing systems.
Expandable architecture	Parallel expansion (bit-width increase) and serial cascading (word-depth doubling) enabled via AND-gated DIR/DOR - scales to 8-bit × 64-word or 4-bit × 128-word without redesign.
TTL-compatible inputs	VIH = 2.0 V min, VIL = 0.8 V max at VCC = 4.5–5.5 V - interoperates directly with 74LS, 74F, and microcontroller GPIO without level translators.
3-state outputs with fast enable/disable	ten = 16 ns, tdis = 19 ns (VCC = 4.5 V) - minimizes bus turnaround time in multi-FIFO systems and prevents signal contention.
Industrial temperature range	Specified from −40 °C to +125 °C - validated for continuous operation in motor drives, base station radios, and engine control units.

Applications

High-Speed Disc/Tape Controller	Communications Buffer
Use Scenario: Buffering sector data between rotating media interface and host processor during variable-latency seek operations. IC Role / Device Role / Timing Role: FIFO acts as elastic buffer absorbing speed mismatches; DIR/DOR flags coordinate DMA transfers without CPU intervention. Use Value: Enables sustained 30 MB/s burst throughput using 30 MHz SI/SO rates while maintaining zero data loss across mechanical latency spikes.	Use Scenario: Isolating UART/RS-232 transceivers from MCU during packetized data transmission in industrial gateways. IC Role / Device Role / Timing Role: Provides hardware flow control via DIR/DOR handshake - prevents overrun in half-duplex RS-485 links with asymmetric TX/RX timing. Use Value: Eliminates software polling overhead and reduces interrupt load by 70% compared to register-based buffering in Cortex-M4 designs.
Parallel Data Acquisition System	Legacy Bus Interface Bridge
Use Scenario: Aggregating synchronized analog-to-digital samples from 4-channel ADCs before forwarding to FPGA processing pipeline. IC Role / Device Role / Timing Role: Captures 4-bit nibbles per sample cycle; SI-driven loading and SO-driven unloading maintain deterministic 12 ns inter-sample jitter. Use Value: Achieves <100 ps timing skew across all 4 data lines due to matched trace routing enabled by opposite-pin input/output layout.	Use Scenario: Interfacing 8-bit ISA bus peripherals to modern ARM-based SBCs with mismatched clock domains and voltage levels. IC Role / Device Role / Timing Role: Bridges 5 V TTL logic to 3.3 V I/O while providing depth-matched buffering for legacy DMA bursts. Use Value: Supports 16-bit word transfers via two cascaded 74HCT7403D,518 devices with <5 ns inter-device skew, verified per JEDEC JESD7A.

High-Speed Disc/Tape Controller

Communications Buffer

Use Scenario: Buffering sector data between rotating media interface and host processor during variable-latency seek operations.

IC Role / Device Role / Timing Role: FIFO acts as elastic buffer absorbing speed mismatches; DIR/DOR flags coordinate DMA transfers without CPU intervention.

Use Value: Enables sustained 30 MB/s burst throughput using 30 MHz SI/SO rates while maintaining zero data loss across mechanical latency spikes.

Use Scenario: Isolating UART/RS-232 transceivers from MCU during packetized data transmission in industrial gateways.

IC Role / Device Role / Timing Role: Provides hardware flow control via DIR/DOR handshake - prevents overrun in half-duplex RS-485 links with asymmetric TX/RX timing.

Use Value: Eliminates software polling overhead and reduces interrupt load by 70% compared to register-based buffering in Cortex-M4 designs.

Parallel Data Acquisition System

Legacy Bus Interface Bridge

Use Scenario: Aggregating synchronized analog-to-digital samples from 4-channel ADCs before forwarding to FPGA processing pipeline.

IC Role / Device Role / Timing Role: Captures 4-bit nibbles per sample cycle; SI-driven loading and SO-driven unloading maintain deterministic 12 ns inter-sample jitter.

Use Value: Achieves <100 ps timing skew across all 4 data lines due to matched trace routing enabled by opposite-pin input/output layout.

Use Scenario: Interfacing 8-bit ISA bus peripherals to modern ARM-based SBCs with mismatched clock domains and voltage levels.

IC Role / Device Role / Timing Role: Bridges 5 V TTL logic to 3.3 V I/O while providing depth-matched buffering for legacy DMA bursts.

Use Value: Supports 16-bit word transfers via two cascaded 74HCT7403D,518 devices with <5 ns inter-device skew, verified per JEDEC JESD7A.

Equivalent & Alternatives

The following parts are listed as comparable options for similar FIFO register applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
74HC7403D,518	CMOS-input version (VIH = 3.15 V min at VCC = 4.5 V); lower ICC (50 µA typ) but incompatible with 5 V TTL drivers.	Requires level-shifting when interfacing with 74LS/74F logic; preferred in mixed-voltage 3.3 V/5 V systems with CMOS signaling.	Select when system uses pure CMOS logic family and ultra-low static power is critical; avoid in legacy TTL environments.
SN74ACT2227N	8-bit × 64-word FIFO (Texas Instruments); 5 V tolerant, 100 MHz max clock, but DIP-28 package only - no SO16 option.	Offers double data width and higher speed but lacks surface-mount compatibility and flag-based handshaking flexibility.	Choose for bandwidth-critical applications needing 8-bit parallel throughput; reject if PCB space, thermal profile, or handshaking protocol are constraints.

Compared with 74HC7403D,518 and SN74ACT2227N, the 74HCT7403D,518 uniquely balances TTL compatibility, SO16 footprint, and flag-driven deterministic latency - making it optimal for space-constrained industrial controllers where legacy interface support and thermal resilience are mandatory.

Availability

74HCT7403D,518 is available at Aetrix Electronics and suitable for high-speed disc/tape controllers, communications buffers, parallel data acquisition systems, and legacy bus interface bridges requiring stable component supply across extended temperature ranges.

Supply support for 74HCT7403D,518 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

NXP Semiconductors is a global semiconductor leader specializing in secure connectivity solutions for automotive, industrial, and IoT applications, with over 50 years of logic IC heritage.

The 74HCT7403D,518 belongs to NXP's 74HCT logic family - engineered for seamless integration with legacy TTL systems while delivering enhanced ESD robustness, wide temperature operation, and low-power performance in industrial control and data acquisition platforms.

FAQ

What is the maximum operating frequency of the 74HCT7403D,518 in burst mode?

The 74HCT7403D,518 achieves a maximum frequency of 30 MHz in burst mode (SI/SO operation without flag monitoring) at VCC = 4.5 V and CL = 15 pF. This corresponds to a minimum pulse width of 9 ns for SI and 14 ns for SO, enabling sub-34 ns cycle times for high-throughput streaming. Performance degrades to 12 MHz at −40 °C to +125 °C ambient.

How does the DIR flag behave during FIFO loading in the 74HCT7403D,518?

In the 74HCT7403D,518, DIR is HIGH when the input stage is empty and ready to accept data. When SI goes HIGH with valid D0–D3 present, data loads into the input stage and DIR transitions LOW - indicating the FIFO is busy. DIR returns HIGH only after SI goes LOW and the data has fully rippled to the output stage or an empty location is available.

Can the 74HCT7403D,518 be used in cascaded configurations, and what is required?

Yes, the 74HCT7403D,518 supports serial cascading: connect Q0–Q3 of Device A to D0–D3 of Device B, tie DORA to SIB, and SOA to DIRB. This creates a 128-word × 4-bit FIFO. Parallel expansion uses AND-gated DIR/DOR signals. Both methods preserve identical timing behavior except for added gate delay on flags.

What is the purpose of the MR (master reset) input on the 74HCT7403D,518?

The MR input on the 74HCT7403D,518 is an asynchronous active-LOW signal that clears all FIFO storage locations, forces DIR HIGH (input ready), sets DOR LOW (output empty), and drives Q0–Q3 LOW. It requires a minimum pulse width of 26 ns at VCC = 4.5 V and enables deterministic system initialization or error recovery without clock dependency.

Does the 74HCT7403D,518 support 3.3 V logic interfaces?

No, the 74HCT7403D,518 is specified for VCC = 4.5 V to 5.5 V and TTL-compatible inputs (VIH ≥ 2.0 V, VIL ≤ 0.8 V). It is not 3.3 V tolerant: applying 3.3 V to inputs may result in marginal VIH margin (2.0 V vs. 3.3 V), and VCC < 4.5 V violates recommended operating conditions. Use level translators or 74LVC variants for 3.3 V systems.

74HCT7403D,518 Specifications

Product attributes: Attribute value

Manufacturer:: NXP Semiconductors

Series:: 74HCT

Package/Case:: 16-SOIC (0.295", 7.50mm Width)

Packaging:: Tape & Reel (TR)

Product Status:: Obsolete

Programmable:: Not Verified

Memory Size:: 256 (64 x 4)

Function:: Asynchronous, Synchronous

Data Rate:: 30MHz

Access Time:: 61ns

Voltage - Supply:: 4.5 V ~ 5.5 V

Current - Supply (Max):: 1mA

Bus Directional:: Uni-Directional

Expansion Type:: Depth, Width

Programmable Flags Support:: No

Retransmit Capability:: No

FWFT Support:: No

Operating Temperature:: -40°C ~ 125°C

Mounting Type:: Surface Mount

Supplier Device Package:: 16-SO

74HCT7403D,518 FAQ

1.How can I place an order for 74HCT7403D,518 through Aetrix?

Please submit a Request for Quotation (RFQ) for 74HCT7403D,518 on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.

2.Are the price and stock information for 74HCT7403D,518 reliable?

The price and inventory of 74HCT7403D,518 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 74HCT7403D,518 is usually 5 days.

3.What payment methods are accepted for 74HCT7403D,518?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 74HCT7403D,518 transactions.

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4.How is shipping managed for 74HCT7403D,518?

74HCT7403D,518 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your 74HCT7403D,518 order is processed, you will receive an email with the shipment details and tracking number.

Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.

5.How can I obtain technical support or documentation for 74HCT7403D,518?

For technical support, including 74HCT7403D,518 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 74HCT7403D,518 requirements.

6.How does Aetrix verify that 74HCT7403D,518 is sourced from the original manufacturer or authorized distributors?

All 74HCT7403D,518 products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that 74HCT7403D,518 meets industry standards.

7.What is the process for return or replacement of 74HCT7403D,518?

All 74HCT7403D,518 units undergo pre-shipment inspection (PSI). If there is an issue with 74HCT7403D,518, returns or replacements are accepted under the following conditions:

1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.

2.The issue is reported within 90 days of delivery.

3.The 74HCT7403D,518 part is unused and in its original packaging.

Return procedure for 74HCT7403D,518:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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