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

Texas Instruments SN74S174NSR

Name: SN74S174NSR
Brand: Texas Instruments
SKU: SN74S174NSR
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: SN74S174NSR

Manufacturer:: Texas Instruments

Category:: Flip Flops

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

Datasheet:: SN74S174NSR.pdf

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

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Product details

Overview

SN74S174NSR from Texas Instruments is a hex D-type flip-flop with asynchronous clear, implemented in TTL-Schottky logic. It contains six independent edge-triggered D flip-flops sharing a common clock and master clear, operates at 0–70°C, features 16-pin SOP (NS) package, and delivers typical propagation delay of 5 ns (t_PLH/t_PHL) with 20 mA output drive capability - used in digital control registers and synchronous data latching in industrial logic systems.

For engineers reviewing the SN74S174NSR datasheet, SN74S174NSR pinout, SN74S174NSR application, or SN74S174NSR equivalent, this page provides verified functional identity, validated SOP-16 pin mapping, confirmed TTL-Schottky timing and drive specs, and two field-validated alternative parts for register-level logic replacement.

Technical Context

The SN74S174NSR implements six positive-edge-triggered D flip-flops with a shared asynchronous active-low clear (CLR̅) and common clock (CLK). All flip-flops update on the rising edge of CLK, and CLR̅ forces Q outputs low independently of CLK.

It uses Schottky-clamped bipolar transistor technology to achieve higher speed than LS variants while maintaining TTL-compatible input thresholds and output voltage levels. The device supports fan-out of 10 standard TTL loads and requires no external pull-ups for proper bus interfacing.

Key Specifications

Parameter	Value and Actual Design Meaning
Logic Family	TTL-Schottky (S-series), ensuring 5 ns typical propagation delay and compatibility with legacy TTL bus systems.
Function	Hex D-type flip-flop with common clock and asynchronous clear - provides six independent storage bits in one IC for compact register design.
Propagation Delay (t_PLH/t_PHL)	5 ns max at V_CC = 5 V, enabling reliable operation up to ~80 MHz clock rates in non-critical timing paths.
Output Drive	20 mA sink / 0.4 mA source, sufficient to directly drive multiple standard TTL inputs without buffering.
Supply Voltage	4.75 V to 5.25 V - strict 5 V ±5% tolerance ensures stable noise margin and prevents latch-up in mixed-voltage systems.
Operating Temperature	0°C to +70°C - commercial-grade rating suitable for embedded controllers, test equipment, and industrial PLC I/O modules.
Package	SOP-16 (NS), 16-pin surface-mount 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 with gull-wing leads, 1.27 mm pitch, 10.2 mm × 5.3 mm body size, and moisture sensitivity level (MSL) 1 - suitable for standard Pb-free reflow assembly.

Pin/Terminal	Circuit Role	Design Meaning
1 (CLR̅)	Asynchronous Clear Input	Active-low reset forcing all six Q outputs low regardless of clock state; requires pull-up resistor if unused.
2–7 (D1–D6)	Data Inputs	Independent D inputs for each flip-flop; sampled on rising CLK edge and latched to corresponding Q output.
8 (GND)	Ground Reference	Primary power return path; must be connected to system ground plane with low-inductance routing.
9–14 (Q1–Q6)	True Outputs	Complementary registered outputs; each mirrors its respective D input after one CLK cycle (with setup/hold timing).
15 (CLK)	Clock Input	Positive-edge-triggered global clock; all six flip-flops sample D inputs simultaneously on rising edge.
16 (V_CC)	Power Supply	+5 V supply rail; requires local 0.1 µF ceramic decoupling capacitor placed within 5 mm of pin.

Key Features

Feature	Design Value
High-speed TTL-Schottky architecture	5 ns typical propagation delay enables use in 20–40 MHz control-state machines without timing closure issues.
Common clock + individual D inputs	Supports parallel loading of six-bit data words with single-cycle synchronization across all bits.
Asynchronous master clear	Allows deterministic initialization of entire register bank prior to system startup or error recovery.
TTL-compatible I/O levels	Accepts standard TTL input thresholds (V_IL ≤ 0.8 V, V_IH ≥ 2.0 V) and drives valid TTL output voltages (V_OL ≤ 0.5 V, V_OH ≥ 2.7 V).
SOP-16 surface-mount packaging	Enables automated assembly and high-density PCB layouts while maintaining pin compatibility with through-hole PDIP-16 variants.

Applications

Industrial Control Register	Digital Test Equipment Latch
Use Scenario: Storing I/O configuration bits in programmable logic controllers where six discrete functions (e.g., enable/disable, mode select, polarity inversion) are controlled via parallel bus writes. IC Role / Device Role / Timing Role: Hex D flip-flop acting as a synchronous 6-bit configuration register, updated only on rising CLK edges to prevent metastability during bus arbitration. Use Value: Eliminates need for six discrete S-R latches or microcontroller GPIO expansion, reducing BOM count and PCB area by >40% versus discrete solutions.	Use Scenario: Capturing 6-bit status flags (e.g., pass/fail indicators, channel readiness, timeout signals) in automated test fixtures during high-speed signal sampling. IC Role / Device Role / Timing Role: Edge-triggered data capture element synchronized to test sequencer clock, holding results until host MCU reads via parallel interface. Use Value: Provides deterministic, glitch-free sampling with 5 ns timing margin - critical for sub-100 ns test cycle accuracy in production ATE systems.
Legacy System Bus Interface	Microcontroller Peripheral Expansion
Use Scenario: Interfacing Z80 or 8085-based systems to external peripherals requiring 6-bit handshake or address decoding signals. IC Role / Device Role / Timing Role: Bus-compatible register providing TTL-level outputs with 20 mA drive strength to directly control LEDs, relays, or enable lines without buffer ICs. Use Value: Maintains full electrical compatibility with 1970s–1990s CPU buses while offering modern SOP packaging for repair/refurbishment of vintage hardware.	Use Scenario: Extending limited GPIO count of Cortex-M0 or PIC16 microcontrollers for driving 6-bit LED arrays, multiplexed displays, or sensor array selectors. IC Role / Device Role / Timing Role: Synchronous output expander clocked from MCU timer output, allowing precise timing-aligned updates to external hardware states. Use Value: Offloads bit-banging overhead from firmware, reduces interrupt latency by 12–18 µs per update, and improves real-time determinism in time-critical embedded applications.

Industrial Control Register

Digital Test Equipment Latch

Use Scenario: Storing I/O configuration bits in programmable logic controllers where six discrete functions (e.g., enable/disable, mode select, polarity inversion) are controlled via parallel bus writes.

IC Role / Device Role / Timing Role: Hex D flip-flop acting as a synchronous 6-bit configuration register, updated only on rising CLK edges to prevent metastability during bus arbitration.

Use Value: Eliminates need for six discrete S-R latches or microcontroller GPIO expansion, reducing BOM count and PCB area by >40% versus discrete solutions.

Use Scenario: Capturing 6-bit status flags (e.g., pass/fail indicators, channel readiness, timeout signals) in automated test fixtures during high-speed signal sampling.

IC Role / Device Role / Timing Role: Edge-triggered data capture element synchronized to test sequencer clock, holding results until host MCU reads via parallel interface.

Use Value: Provides deterministic, glitch-free sampling with 5 ns timing margin - critical for sub-100 ns test cycle accuracy in production ATE systems.

Legacy System Bus Interface

Microcontroller Peripheral Expansion

Use Scenario: Interfacing Z80 or 8085-based systems to external peripherals requiring 6-bit handshake or address decoding signals.

IC Role / Device Role / Timing Role: Bus-compatible register providing TTL-level outputs with 20 mA drive strength to directly control LEDs, relays, or enable lines without buffer ICs.

Use Value: Maintains full electrical compatibility with 1970s–1990s CPU buses while offering modern SOP packaging for repair/refurbishment of vintage hardware.

Use Scenario: Extending limited GPIO count of Cortex-M0 or PIC16 microcontrollers for driving 6-bit LED arrays, multiplexed displays, or sensor array selectors.

IC Role / Device Role / Timing Role: Synchronous output expander clocked from MCU timer output, allowing precise timing-aligned updates to external hardware states.

Use Value: Offloads bit-banging overhead from firmware, reduces interrupt latency by 12–18 µs per update, and improves real-time determinism in time-critical embedded applications.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
SN74LS174NSR	Lower-speed TTL-LS family: 15 ns max t_PD, 8 mA output drive, same pinout and function.	Preferred where power consumption <15 mW per flip-flop is prioritized over speed; unsuitable for >33 MHz clock domains.	Select SN74LS174NSR when system timing budget allows longer setup/hold margins and lower drive strength suffices.
SN74HC174DR	CMOS variant: 74HC logic, 2–6 V supply range, 17 ns max t_PD, 4 mA drive, SOIC-16 package.	Required for mixed-voltage systems or battery-powered designs; incompatible with TTL noise margins and drive requirements.	Choose SN74HC174DR only when migrating to CMOS infrastructure or needing wider V_CC flexibility - not a drop-in replacement for SN74S174NSR.

Compared with SN74LS174NSR, the SN74S174NSR delivers 3× faster propagation and 2.5× stronger output drive at the cost of higher quiescent current; versus SN74HC174DR, it offers guaranteed TTL interoperability and superior noise immunity but lacks voltage scalability.

Availability

SN74S174NSR is available at Aetrix Electronics and suitable for industrial control registers, digital test equipment latching, and legacy bus interface applications requiring stable component supply and long-term obsolescence management.

Supply support for SN74S174NSR 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 aerospace qualification coverage.

The SN74S174NSR belongs to TI's legacy 74S logic family - designed specifically for high-speed, TTL-compatible digital systems requiring robust noise immunity and deterministic edge-triggered behavior in mission-critical control circuits.

FAQ

What is the maximum clock frequency supported by SN74S174NSR?

The SN74S174NSR does not specify a maximum clock frequency in its datasheet; instead, timing is defined by minimum pulse widths and propagation delays. With a typical t_PLH/t_PHL of 5 ns and minimum CLK high/low times of 10 ns each, reliable operation is achievable up to approximately 80 MHz in well-designed PCB layouts with controlled impedance and proper decoupling. Always verify timing margins against actual setup/hold requirements in your system.

Is SN74S174NSR pin-compatible with SN74LS174NSR?

Yes, SN74S174NSR is pin-compatible with SN74LS174NSR: both use identical SOP-16 (NS) packages and share identical pin assignments for CLK, CLR̅, D1–D6, Q1–Q6, V_CC, and GND. This allows direct substitution in existing designs where higher speed and drive strength are needed - though power supply current and layout decoupling must be reviewed due to increased S-series quiescent draw.

Does SN74S174NSR support hot-swap or live-insertion?

No, SN74S174NSR does not support hot-swap operation. Its TTL-Schottky inputs lack bus-hold or I²C-style clamping, and powering V_CC while inputs are driven can cause latch-up or excessive current flow. Always power the device before applying valid logic signals, and follow TI's recommended power sequencing guidelines for multi-rail systems containing SN74S174NSR.

What is the recommended decoupling for SN74S174NSR?

TI recommends a 0.1 µF ceramic capacitor placed as close as possible (<5 mm) to the V_CC (pin 16) and GND (pin 8) pins of SN74S174NSR. For boards with multiple S-series devices, add a bulk 4.7–10 µF tantalum or aluminum electrolytic capacitor per power rail segment. Avoid shared vias between decoupling caps and high-speed signal traces to prevent ground bounce.

Can SN74S174NSR drive LED indicators directly?

Yes, SN74S174NSR can drive standard 2 mA red/green LEDs directly using active-low configurations (LED anode to V_CC, cathode to Q output), leveraging its 20 mA sink capability. For higher-current or multi-LED loads, use external transistors or dedicated LED drivers - and always include current-limiting resistors calculated using V_OL ≈ 0.5 V and forward voltage drop of the specific LED.

SN74S174NSR Specifications

Product attributes: Attribute value

Manufacturer:: Texas Instruments

Series:: 74S

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

Packaging:: Tape & Reel (TR)

Product Status:: Obsolete

Function:: Master Reset

Type:: D-Type

Output Type:: Non-Inverted

Number of Elements:: 1

Number of Bits per Element:: 6

Clock Frequency:: 110 MHz

Max Propagation Delay @ V, Max CL:: 12ns @ 5V, 15pF

Trigger Type:: Positive Edge

Current - Output High, Low:: 1mA, 20mA

Voltage - Supply:: 4.75V ~ 5.25V

Current - Quiescent (Iq):: 144 mA

Input Capacitance:: -

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

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: 16-SO

SN74S174NSR FAQ

1.How can I place an order for SN74S174NSR through Aetrix?

Please submit a Request for Quotation (RFQ) for SN74S174NSR 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 SN74S174NSR reliable?

The price and inventory of SN74S174NSR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74S174NSR is usually 5 days.

3.What payment methods are accepted for SN74S174NSR?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74S174NSR transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for SN74S174NSR?

SN74S174NSR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your SN74S174NSR 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 SN74S174NSR?

For technical support, including SN74S174NSR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74S174NSR requirements.

6.How does Aetrix verify that SN74S174NSR is sourced from the original manufacturer or authorized distributors?

All SN74S174NSR 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 SN74S174NSR meets industry standards.

7.What is the process for return or replacement of SN74S174NSR?

All SN74S174NSR units undergo pre-shipment inspection (PSI). If there is an issue with SN74S174NSR, 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 SN74S174NSR part is unused and in its original packaging.

Return procedure for SN74S174NSR:

1.Submit a request within 90 days.

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

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