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

Texas Instruments SN74ALS174DR

Name: SN74ALS174DR
Brand: Texas Instruments
SKU: SN74ALS174DR
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: SN74ALS174DR

Manufacturer:: Texas Instruments

Category:: Flip Flops

Package:: 16-SOIC (0.154", 3.90mm Width)

Datasheet:: SN74ALS174DR.pdf

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

Quantity:: RFQ Add To RFQ list

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Product details

Overview

SN74ALS174DR from Texas Instruments is a hex D-type positive-edge-triggered flip-flop with asynchronous clear, implemented in advanced low-power Schottky (ALS) TTL logic. It contains six independent single-rail D-flip-flops, features buffered clock and direct-clear inputs, operates at 5 V, supports 50 MHz maximum clock frequency, and delivers 4 mA low-level output drive. It is used in synchronous digital systems for data latching and register storage.

For engineers reviewing the SN74ALS174DR datasheet, SN74ALS174DR pinout, SN74ALS174DR application, or SN74ALS174DR equivalent, this page provides verified functional identity, SOIC-16 package mapping, timing parameters (t_su = 10 ns, t_PLH = 3 ns), absolute max ratings (V_CC = 7 V), and validated alternatives for legacy TTL register design.

Technical Context

The SN74ALS174DR implements six identical D-type flip-flops sharing a common buffered clock (CLK) and asynchronous clear (CLR) input. Each flip-flop transfers data from its D input to Q output on the positive-going edge of CLK, provided setup (10 ns) and hold (0 ns) timing requirements are met.

All inputs and outputs are TTL-compatible: V_IL = 0.8 V, V_IH = 2.0 V, V_OL = 0.4 V at I_OL = 4 mA, and V_OH = V_CC–2 V at I_OH = –0.4 mA. The device draws 11–19 mA ICC at V_CC = 5.5 V and operates across 0°C to 70°C.

Key Specifications

Parameter	Value and Actual Design Meaning
Logic Family	Advanced Low-Power Schottky (ALS) TTL - ensures compatibility with standard TTL while reducing power vs. LS series.
Function	Hex D-type flip-flop with asynchronous clear - six independent storage elements per IC for parallel register implementation.
Max Clock Frequency	50 MHz - enables reliable operation in high-speed synchronous logic up to 20 ns period.
Propagation Delay	t_PLH/t_PHL = 3–15 ns (CLK→Q) - guarantees fast state update critical for pipeline and control register timing.
Output Drive	I_OL = 4 mA / I_OH = –0.4 mA - sufficient fanout for driving multiple TTL inputs without buffering.
Supply Voltage	V_CC = 4.5–5.5 V - strict 5 V nominal operation; not tolerant of wide-range or mixed-voltage rail designs.
Operating Temperature	0°C to 70°C - commercial-grade rating suitable for industrial control panels and non-military embedded systems.

Pinout & Package

SN74ALS174DR is housed in a 16-pin SOIC (D) package with 1.27 mm pitch, 7.5 mm width, and 10.3 mm length. Pin 1 is located at the top-left corner (quadrant Q1) when viewed from the top with marking side up and notch/indentation oriented left.

Pin/Terminal	Circuit Role	Design Meaning
1	CLR	Asynchronous active-low clear - resets all six Q outputs to logic low regardless of clock state.
2	1D	Data input for flip-flop 1 - sampled on rising CLK edge and transferred to 1Q.
3	1Q	True output for flip-flop 1 - reflects stored D value after clock edge; no complementary output.
4	2D	Data input for flip-flop 2 - independent channel with dedicated D/Q pair.
5	2Q	True output for flip-flop 2 - single-rail output only (no Q̅).
6	3D	Data input for flip-flop 3 - third of six identical D-flip-flop channels.
7	3Q	True output for flip-flop 3 - matches timing and drive specs of other Q outputs.
8	GND	Ground reference - must be connected to system 0 V plane; decoupling capacitor recommended near pin.
9	4D	Data input for flip-flop 4 - fourth channel; shares same electrical characteristics as 1D–3D.
10	4Q	True output for flip-flop 4 - fully buffered for noise immunity in dense PCB layouts.
11	5D	Data input for flip-flop 5 - fifth D-input; no internal connection to NC pins.
12	5Q	True output for flip-flop 5 - electrically identical to 1Q–4Q; supports fanout of ≥10 TTL loads.
13	6D	Data input for flip-flop 6 - final D input in the hex configuration.
14	6Q	True output for flip-flop 6 - completes the set of six Q outputs; no NC or unused pins among Qs.
15	CLK	Buffered clock input - positive-edge sensitive; internal Schmitt trigger not present; requires clean TTL-level transitions.
16	V_CC	+5 V supply - must be decoupled with 0.1 µF ceramic capacitor placed within 5 mm of pin.

Key Features

Feature	Design Value
Hex D-type flip-flop architecture	Six independent storage cells enable compact 6-bit latch/register without external gating or duplication.
Asynchronous clear (CLR)	Global reset capability allows synchronized initialization of all six bits without clock dependency.
Buffered clock and clear inputs	Reduces loading on upstream drivers and improves noise margin in multi-device clock trees.
TTL-compatible I/O levels	Direct interface with 74LS, 74F, and other TTL families without level-shifting circuitry.
SOIC-16 RoHS-compliant packaging	Surface-mount footprint (7.5 × 10.3 mm) supports automated assembly and meets lead-free soldering standards (Level-1-260°C).

Applications

Buffer/Storage Register	Shift Register Stage
Use Scenario: Holding parallel data from an ADC or microcontroller bus before processing or transmission. IC Role / Device Role / Timing Role: Six-bit parallel data latch synchronizing asynchronous input with system clock domain. Use Value: Ensures stable, glitch-free sampling at up to 50 MHz with 10 ns setup time margin for timing-critical acquisition.	Use Scenario: Implementing one stage of a serial-in/parallel-out (SIPO) shift register for LED display control. IC Role / Device Role / Timing Role: Edge-triggered storage element advancing data on each CLK pulse in a cascaded chain. Use Value: Propagation delay ≤15 ns enables tight inter-stage timing for >20 MHz shift rates without skew accumulation.
Pattern Generator	Control Logic Register
Use Scenario: Generating fixed test patterns (e.g., walking 1s, checkerboard) for digital circuit validation. IC Role / Device Role / Timing Role: Deterministic state-holding block initialized via CLR and loaded with predefined D inputs. Use Value: Single-rail Q outputs simplify pattern decoding logic; ALS speed supports real-time test vector generation.	Use Scenario: Storing configuration bits for FPGA I/O banks or programmable logic controller (PLC) I/O modules. IC Role / Device Role / Timing Role: Nonvolatile register holding mode/control settings between power cycles (with external retention). Use Value: 4 mA output drive directly interfaces with LED indicators or optocoupler inputs without external buffers.

Buffer/Storage Register

Shift Register Stage

Use Scenario: Holding parallel data from an ADC or microcontroller bus before processing or transmission.

IC Role / Device Role / Timing Role: Six-bit parallel data latch synchronizing asynchronous input with system clock domain.

Use Value: Ensures stable, glitch-free sampling at up to 50 MHz with 10 ns setup time margin for timing-critical acquisition.

Use Scenario: Implementing one stage of a serial-in/parallel-out (SIPO) shift register for LED display control.

IC Role / Device Role / Timing Role: Edge-triggered storage element advancing data on each CLK pulse in a cascaded chain.

Use Value: Propagation delay ≤15 ns enables tight inter-stage timing for >20 MHz shift rates without skew accumulation.

Pattern Generator

Control Logic Register

Use Scenario: Generating fixed test patterns (e.g., walking 1s, checkerboard) for digital circuit validation.

IC Role / Device Role / Timing Role: Deterministic state-holding block initialized via CLR and loaded with predefined D inputs.

Use Value: Single-rail Q outputs simplify pattern decoding logic; ALS speed supports real-time test vector generation.

Use Scenario: Storing configuration bits for FPGA I/O banks or programmable logic controller (PLC) I/O modules.

IC Role / Device Role / Timing Role: Nonvolatile register holding mode/control settings between power cycles (with external retention).

Use Value: 4 mA output drive directly interfaces with LED indicators or optocoupler inputs without external buffers.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
SN74ALS174N	Same ALS logic, identical function and timing, but in 16-pin PDIP (N) package with through-hole mounting.	Preferred for prototyping, breadboarding, or legacy through-hole production where SOIC reflow is unavailable.	Select SN74ALS174N when manual assembly, socketing, or thermal testing on leaded packages is required.
SN74AS174DR	Faster AS-family variant: 100 MHz f_max, 3.5 ns t_PLH, higher ICC (30–45 mA), and improved noise immunity via full output buffering.	Suitable for higher-speed register files or clock-domain crossing where ALS timing margins are insufficient.	Choose SN74AS174DR when >50 MHz operation or lower propagation skew is mandatory; verify power delivery capability.

Compared with SN74ALS174N, the SN74ALS174DR offers surface-mount reliability and smaller footprint, while SN74AS174DR trades higher power for 2× clock speed and tighter timing - enabling upgrades without logic redesign.

Availability

SN74ALS174DR is available at Aetrix Electronics and suitable for industrial control panels, legacy instrumentation, and military-grade repair programs requiring stable component supply and long-term traceability.

Supply support for SN74ALS174DR 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 global semiconductor leader founded in 1930, specializing in analog, embedded processing, and logic solutions with broad industrial and automotive reach.

The SN74ALS174DR belongs to TI's legacy 74ALS logic family, designed specifically for high-reliability, medium-speed TTL-compatible digital systems where power efficiency and noise immunity outweigh ultra-high speed requirements.

FAQ

What is the maximum clock frequency supported by SN74ALS174DR?

The SN74ALS174DR supports a maximum clock frequency of 50 MHz under recommended operating conditions (V_CC = 4.5–5.5 V, T_A = 0°C to 70°C). This is confirmed by timing parameter f_max = 50 MHz in the SDAS207E datasheet, derived from t_PLH/t_PHL propagation delays and minimum pulse widths. Exceeding this limit risks metastability or incorrect state capture in the SN74ALS174DR.

Does SN74ALS174DR provide complementary (Q and Q̅) outputs?

No, the SN74ALS174DR provides only true (Q) outputs for all six flip-flops. Complementary outputs are exclusive to the 'ALS175 and 'AS175B variants, which contain four flip-flops with dual-rail outputs. The SN74ALS174DR datasheet explicitly states "'ALS174 and 'AS174 Contain Six Flip-Flops With Single-Rail Outputs", confirming absence of Q̅ terminals in the SN74ALS174DR.

What is the recommended decoupling for SN74ALS174DR?

A 0.1 µF ceramic capacitor should be placed between V_CC (pin 16) and GND (pin 8) as close as possible to the SN74ALS174DR - ideally within 5 mm - to suppress high-frequency supply noise. For systems with multiple SN74ALS174DR devices, add a bulk 4.7 µF electrolytic capacitor per board section. This decoupling strategy is specified in TI application guidance for ALS devices and prevents output glitches caused by V_CC droop during simultaneous switching.

Can SN74ALS174DR be used in place of SN74AS174DR?

The SN74ALS174DR is functionally pin-compatible with SN74AS174DR but not a direct drop-in replacement due to key differences: SN74ALS174DR has lower speed (50 MHz vs. 100 MHz), reduced output drive (4 mA vs. 20 mA), and higher propagation delay (3–15 ns vs. 3.5–9.5 ns). It may operate in AS-designed circuits at reduced clock rates, but timing closure and fanout must be re-verified. The SN74ALS174DR is not rated for AS-level performance.

What does the "DR" suffix indicate in SN74ALS174DR?

The "DR" suffix in SN74ALS174DR denotes a 16-pin SOIC (D) package supplied in tape-and-reel format with a quantity of 2500 units per reel. Per TI's ordering information, SN74ALS174DR uses NiPdAu (NIPDAU) lead finish, complies with RoHS, and carries a moisture sensitivity level (MSL) rating of Level-1-260°C-UNLIM - meaning it is not moisture-sensitive and requires no baking prior to reflow soldering. This distinguishes it from the tube-packaged SN74ALS174D.

SN74ALS174DR Specifications

Product attributes: Attribute value

Manufacturer:: Texas Instruments

Series:: 74ALS

Package/Case:: 16-SOIC (0.154", 3.90mm Width)

Packaging:: Tape & Reel (TR)

Product Status:: Active

Function:: Master Reset

Type:: D-Type

Output Type:: Non-Inverted

Number of Elements:: 1

Number of Bits per Element:: 6

Clock Frequency:: 50 MHz

Max Propagation Delay @ V, Max CL:: 17ns @ 5V, 50pF

Trigger Type:: Positive Edge

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

Voltage - Supply:: 4.5V ~ 5.5V

Current - Quiescent (Iq):: 19 mA

Input Capacitance:: -

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

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: 16-SOIC

SN74ALS174DR FAQ

1.How can I place an order for SN74ALS174DR through Aetrix?

Please submit a Request for Quotation (RFQ) for SN74ALS174DR 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 SN74ALS174DR reliable?

The price and inventory of SN74ALS174DR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74ALS174DR is usually 5 days.

3.What payment methods are accepted for SN74ALS174DR?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74ALS174DR transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for SN74ALS174DR?

SN74ALS174DR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your SN74ALS174DR 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 SN74ALS174DR?

For technical support, including SN74ALS174DR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74ALS174DR requirements.

6.How does Aetrix verify that SN74ALS174DR is sourced from the original manufacturer or authorized distributors?

All SN74ALS174DR 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 SN74ALS174DR meets industry standards.

7.What is the process for return or replacement of SN74ALS174DR?

All SN74ALS174DR units undergo pre-shipment inspection (PSI). If there is an issue with SN74ALS174DR, 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 SN74ALS174DR part is unused and in its original packaging.

Return procedure for SN74ALS174DR:

1.Submit a request within 90 days.

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

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