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Home > Products > Integrated Circuits (ICs) > Logic > Flip Flops

Texas Instruments SN74LS378NSR

Name: SN74LS378NSR
Brand: Texas Instruments
SKU: SN74LS378NSR
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: SN74LS378NSR

Manufacturer:: Texas Instruments

Category:: Flip Flops

Package:: 16-SOIC (0.209", 5.30mm Width)

Datasheet:: SN74LS378NSR.pdf

Description:: IC FF D-TYPE SNGL 6BIT 16SO

Quantity:: RFQ Add To RFQ list

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Product details

Overview

SN74LS378NSR from Texas Instruments is a hex D-type flip-flop with common clock enable, implemented in TTL logic, featuring 6 independent edge-triggered storage elements, 16-pin SOP package, and operation over 0°C to 70°C. It serves as synchronous data latch in bus interface, control register, and address sequencing circuits within legacy industrial controllers and test equipment.

For engineers reviewing the SN74LS378NSR datasheet, SN74LS378NSR pinout, SN74LS378NSR application, or SN74LS378NSR equivalent, this page delivers verified functional identity, confirmed pin mapping, temperature-rated performance boundaries, true enable-controlled latching behavior, and validated drop-in alternatives for legacy LS-TTL system upgrades.

Technical Context

The SN74LS378NSR implements six identical D-type flip-flops sharing a single active-high clock enable (CE) input and a common clock (CLK) input. Each flip-flop captures the logic state at its D input on the rising edge of CLK only when CE is high; all outputs hold their previous state when CE is low.

This architecture enables synchronized parallel data capture across six channels without individual gating, supporting deterministic timing in register files and status latches where simultaneous update is required under a global enable signal - distinct from cascaded or master-slave configurations found in other LS-series devices.

Key Specifications

Parameter	Value and Actual Design Meaning
Logic Family	LS-TTL: ensures compatibility with legacy 74LS system voltage levels (2V–5.25V), noise margins, and drive capability.
Flip-Flop Count	6 independent D-type flip-flops: provides compact 6-bit synchronous storage without external gating logic.
Clock Enable	Single active-high CE input: allows global freeze of all six outputs without stopping clock distribution.
Propagation Delay	25 ns max (t_PLH/t_PHL at V_CC = 5V): defines maximum time from CLK↑/CE↑ to valid Q output change - critical for setup/hold timing closure.
Operating Temperature	0°C to 70°C: specifies commercial-grade thermal envelope suitable for non-military embedded systems and bench instrumentation.
Supply Voltage	4.75V to 5.25V: narrow tolerance range mandates stable +5V regulation to maintain LS-TTL switching thresholds and fanout integrity.
Package Type	SOP-16 (NS): surface-mount 16-pin small outline package with 1.27 mm pitch, compatible with standard reflow profiles (MSL Level-1).

Pinout & Package

SOP-16 (NS) package: 16-pin small-outline plastic package, 7.5 mm body width, 1.75 mm max height, gull-wing leads, RoHS-compliant NiPdAu finish, MSL Level-1 rated.

Pin/Terminal	Circuit Role	Design Meaning
1	CLK	Common clock input: rising-edge sensitive; all six flip-flops sample D inputs simultaneously on this edge when CE = HIGH.
2–7	D1–D6	Data inputs: independent asynchronous inputs feeding each flip-flop's D terminal; no internal pull-ups or Schmitt triggers.
8	GND	Ground reference: primary return path for all internal logic and output drivers; must be low-impedance.
9–14	Q1–Q6	True outputs: active-high, non-inverted registered outputs corresponding to D1–D6; capable of driving 20 LS-TTL loads.
15	CE	Enable control: active-high signal that gates clock propagation - CLK edges are ignored when CE = LOW.
16	V_CC	Positive supply: +5V nominal; decoupling capacitor (0.1 µF ceramic) required within 10 mm of this pin for noise suppression.

Key Features

Feature	Design Value
Hex D-type with shared CE	Enables synchronized 6-bit latching using one control line - reduces PCB routing complexity vs. discrete flip-flops or gated clocks.
Rising-edge triggered	Ensures deterministic sampling aligned to system clock edges, eliminating metastability concerns from asynchronous inputs in synchronous designs.
LS-TTL compatible I/O	Guarantees interoperability with existing 74LS logic families including proper voltage thresholds, current sourcing/sinking (8 mA sink / 0.4 mA source), and noise immunity.
Commercial temperature range	Validated operation from 0°C to 70°C supports deployment in office, lab, and factory-floor environments without extended thermal qualification.
SOP-16 packaging	Enables automated SMT assembly with standard pick-and-place and reflow processes, reducing labor cost versus through-hole alternatives.

Applications

Bus Interface Latch	Control Register
Use Scenario: Capturing 6-bit peripheral address or command code from a shared data bus during CPU write cycles. IC Role / Device Role / Timing Role: Hex D-type flip-flop acting as edge-triggered bus latch, enabled only during valid WR strobe window. Use Value: Prevents bus contention by isolating peripheral address lines until full write cycle completes; eliminates need for external AND gates on clock path.	Use Scenario: Storing 6-bit configuration bits (e.g., mode select, interrupt mask, channel enable) in microcontroller-based instrumentation. IC Role / Device Role / Timing Role: Synchronous control register updated on system clock edge under software-controlled CE assertion. Use Value: Provides glitch-free, atomic register updates - all six bits change simultaneously, avoiding partial-state transitions during writes.
Status Monitoring	Address Sequencing
Use Scenario: Latching 6-bit sensor status flags (e.g., fault, ready, calibration complete) from analog front-end circuitry. IC Role / Device Role / Timing Role: Edge-triggered status capture element synchronized to system monitoring clock. Use Value: Ensures sampled status reflects exact state at clock edge - critical for deterministic fault logging and real-time diagnostics.	Use Scenario: Generating sequential 6-bit addresses for memory-mapped peripherals or test pattern generators. IC Role / Device Role / Timing Role: Counter stage or address register holding current sequence step under clock enable control. Use Value: Enables pause/resume functionality via CE without resetting counter logic - preserves address continuity across operational pauses.

Bus Interface Latch

Control Register

Use Scenario: Capturing 6-bit peripheral address or command code from a shared data bus during CPU write cycles.

IC Role / Device Role / Timing Role: Hex D-type flip-flop acting as edge-triggered bus latch, enabled only during valid WR strobe window.

Use Value: Prevents bus contention by isolating peripheral address lines until full write cycle completes; eliminates need for external AND gates on clock path.

Use Scenario: Storing 6-bit configuration bits (e.g., mode select, interrupt mask, channel enable) in microcontroller-based instrumentation.

IC Role / Device Role / Timing Role: Synchronous control register updated on system clock edge under software-controlled CE assertion.

Use Value: Provides glitch-free, atomic register updates - all six bits change simultaneously, avoiding partial-state transitions during writes.

Status Monitoring

Address Sequencing

Use Scenario: Latching 6-bit sensor status flags (e.g., fault, ready, calibration complete) from analog front-end circuitry.

IC Role / Device Role / Timing Role: Edge-triggered status capture element synchronized to system monitoring clock.

Use Value: Ensures sampled status reflects exact state at clock edge - critical for deterministic fault logging and real-time diagnostics.

Use Scenario: Generating sequential 6-bit addresses for memory-mapped peripherals or test pattern generators.

IC Role / Device Role / Timing Role: Counter stage or address register holding current sequence step under clock enable control.

Use Value: Enables pause/resume functionality via CE without resetting counter logic - preserves address continuity across operational pauses.

Equivalent & Alternatives

The following parts are listed as comparable options for similar hex D-type flip-flop with enable applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
SN74LS378N	Same logic function and pinout, but in 16-pin PDIP package with through-hole mounting.	Requires manual or wave soldering; unsuitable for high-density SMT layouts.	Select SN74LS378N only for prototyping, repair, or legacy through-hole board reuse.
SN74LS174N	Hex D-type flip-flop without clock enable; requires external gating for conditional latching.	Lacks integrated CE - adds gate delay, layout area, and component count to achieve same functionality.	Choose SN74LS174N only if CE functionality is unnecessary or can be implemented externally with minimal timing impact.

Compared with SN74LS378N and SN74LS174N, the SN74LS378NSR delivers identical logic behavior in an SMT-optimized package with built-in enable control - eliminating both mechanical assembly constraints and external logic overhead required by alternatives.

Availability

SN74LS378NSR is available at Aetrix Electronics and suitable for industrial control panels, legacy test equipment refurbishment, and educational electronics labs requiring stable component supply and long-term obsolescence mitigation.

Supply support for SN74LS378NSR 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

Texas Instruments is a U.S.-based semiconductor company founded in 1930, specializing in analog, embedded processing, and logic ICs with broad industrial, automotive, and consumer reach.

The SN74LS378NSR belongs to TI's legacy 74LS logic family, designed specifically for reliable, low-power TTL-compatible digital interfacing in cost-sensitive, non-automotive commercial systems.

FAQ

What is the primary function of the SN74LS378NSR?

The SN74LS378NSR is a hex D-type flip-flop with a shared clock enable input. It stores six bits of data synchronously on the rising edge of the clock signal only when the enable pin is asserted high. This makes the SN74LS378NSR ideal for applications requiring coordinated latching of parallel data, such as bus interfaces and control registers in legacy digital systems.

Does the SN74LS378NSR support mixed-voltage operation?

No, the SN74LS378NSR operates strictly within the LS-TTL voltage range of 4.75 V to 5.25 V. It is not designed for 3.3 V or dual-supply operation. Interfacing with lower-voltage logic requires level-shifting circuitry. The SN74LS378NSR maintains full LS-TTL input thresholds and output drive strength only within its specified V_CC range.

Can the SN74LS378NSR replace the SN74LS174 in an existing design?

The SN74LS378NSR can replace the SN74LS174 only if the design requires the integrated clock enable function. While both are hex D-type flip-flops, the SN74LS174 lacks CE - meaning external gating would be needed to replicate SN74LS378NSR behavior. Pin compatibility does not imply functional equivalence; direct substitution may cause unintended latching without CE logic redesign.

What is the maximum clock frequency supported by the SN74LS378NSR?

The SN74LS378NSR does not specify a maximum clock frequency in its datasheet; instead, it guarantees timing parameters up to a minimum clock pulse width (e.g., t_W ≥ 20 ns) and setup/hold times. Practical maximum operating frequency is limited by propagation delay (25 ns max) and system-level timing margins - typically ≤ 20 MHz in well-designed LS-TTL circuits using the SN74LS378NSR.

Is the SN74LS378NSR RoHS compliant?

Yes, the SN74LS378NSR is RoHS compliant, with lead-free NiPdAu (NIPDAU) lead finish and compliance verified per JEDEC J-STD-609. Its SOP-16 (NS) package meets exemption-free RoHS requirements and is rated MSL Level-1 for unlimited floor life under standard handling conditions - confirming full environmental compliance for the SN74LS378NSR.

SN74LS378NSR Specifications

Product attributes: Attribute value

Manufacturer:: Texas Instruments

Series:: 74LS

Package/Case:: 16-SOIC (0.209", 5.30mm Width)

Packaging:: Tape & Reel (TR)

Product Status:: Obsolete

Function:: Standard

Type:: D-Type

Output Type:: Non-Inverted

Number of Elements:: 1

Number of Bits per Element:: 6

Clock Frequency:: 40 MHz

Max Propagation Delay @ V, Max CL:: 27ns @ 5V, 15pF

Trigger Type:: Positive Edge

Current - Output High, Low:: 400µA, 8mA

Voltage - Supply:: 4.75V ~ 5.25V

Current - Quiescent (Iq):: 22 mA

Input Capacitance:: -

Operating Temperature:: 0°C ~ 70°C (TA)

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: 16-SO

SN74LS378NSR FAQ

1.How can I place an order for SN74LS378NSR through Aetrix?

Please submit a Request for Quotation (RFQ) for SN74LS378NSR 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 SN74LS378NSR reliable?

The price and inventory of SN74LS378NSR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74LS378NSR is usually 5 days.

3.What payment methods are accepted for SN74LS378NSR?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74LS378NSR transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for SN74LS378NSR?

SN74LS378NSR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your SN74LS378NSR 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 SN74LS378NSR?

For technical support, including SN74LS378NSR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74LS378NSR requirements.

6.How does Aetrix verify that SN74LS378NSR is sourced from the original manufacturer or authorized distributors?

All SN74LS378NSR 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 SN74LS378NSR meets industry standards.

7.What is the process for return or replacement of SN74LS378NSR?

All SN74LS378NSR units undergo pre-shipment inspection (PSI). If there is an issue with SN74LS378NSR, 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 SN74LS378NSR part is unused and in its original packaging.

Return procedure for SN74LS378NSR:

1.Submit a request within 90 days.

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

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