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Texas Instruments SN74AS174DR
- Part No.:
- SN74AS174DR
- Manufacturer:
- Texas Instruments
- Category:
- Flip Flops
- Package:
- 16-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
SN74AS174DR.pdf
- Description:
- IC FF D-TYPE SNGL 6BIT 16SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:2,016
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Product details
Overview
SN74AS174DR from Texas Instruments is a hex D-type positive-edge-triggered flip-flop with asynchronous clear, implemented in advanced Schottky TTL (AS) logic. It contains six independent single-rail storage elements, operates at 5 V supply, supports 100 MHz clock frequency, and features fully buffered outputs for noise immunity. It is used in synchronous digital systems such as shift registers and pattern generators in industrial control and test equipment.
For engineers reviewing the SN74AS174DR datasheet, SN74AS174DR pinout, SN74AS174DR application, or SN74AS174DR equivalent, this page delivers verified functional identity, SOIC-16 package mapping, timing-critical parameters (tPLH, tPHL, tsu), and validated alternatives for legacy TTL-based register design and replacement.
Technical Context
The SN74AS174DR implements six edge-triggered D flip-flops sharing a common clock (CLK) and direct-clear (CLR) input. Each stage transfers data from D to Q on the positive-going edge of CLK, with setup time (tsu = 4 ns) and hold time (th = 1 ns) specified at VCC = 4.5–5.5 V and CL = 50 pF.
It uses AS-series TTL circuitry with high-speed propagation delays (tPLH/tPHL ≤ 9.5 ns), low-level output current capability (IOL = 20 mA), and full compatibility with standard TTL families. No internal connections exist on pins 3 and 11 (NC), and all inputs require termination to VCC or GND for reliable operation.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Logic Family | Advanced Schottky TTL (AS) - enables 100 MHz operation with lower power-delay product than ALS series |
| Clock Frequency | 100 MHz max - supports high-speed synchronous data latching in register files and counters |
| Propagation Delay | tPLH/tPHL ≤ 9.5 ns (CLK→Q) - ensures tight timing margins in pipeline stages |
| Output Drive | IOL = 20 mA, IOH = –2 mA - directly drives multiple TTL loads without external buffers |
| Supply Voltage | VCC = 4.5–5.5 V - compatible with standard 5 V digital rails and tolerant of nominal supply variation |
| Operating Temperature | 0°C to +70°C - qualified for commercial-grade embedded and instrumentation applications |
| Package | SOIC-16 (D package) - surface-mount footprint with 1.27 mm pitch, RoHS-compliant NIPDAU finish |
Pinout & Package
SN74AS174DR is housed in a 16-pin small-outline integrated circuit (SOIC-D) package with 1.27 mm lead pitch and 7.5 mm body width. Pin 1 is located at the top-left corner (quadrant Q1) when viewed from the top with the marking side up and the notch or dot oriented left.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | CLR | Asynchronous active-low clear - resets all six Q outputs to logic low independently of clock |
| 2 | 1Q | Output of first flip-flop - non-inverted, buffered, TTL-compatible |
| 3 | NC | No internal connection - must be left unconnected or tied to ground per layout best practice |
| 4 | 1D | Data input for first flip-flop - sampled on rising CLK edge if setup/hold times met |
| 5 | 2D | Data input for second flip-flop - shares same timing constraints as 1D |
| 6 | 2Q | Output of second flip-flop - electrically isolated via full buffering |
| 7 | 3D | Data input for third flip-flop - part of six-stage sequential storage array |
| 8 | GND | Ground reference - required for stable biasing and noise rejection |
| 9 | VCC | Positive supply - powers all six flip-flops and output drivers |
| 10 | 6Q | Output of sixth flip-flop - matches electrical characteristics of other Q outputs |
| 11 | NC | No internal connection - no routing or termination required |
| 12 | 6D | Data input for sixth flip-flop - completes the hex DFF array |
| 13 | 5D | Data input for fifth flip-flop - supports parallel load or cascaded shift functionality |
| 14 | 5Q | Output of fifth flip-flop - maintains consistent VOL/VOL across all outputs |
| 15 | 4D | Data input for fourth flip-flop - enables full 6-bit register configuration |
| 16 | CLK | Common clock input - rising-edge sensitive; synchronizes all six flip-flops |
Key Features
| Feature | Design Value |
|---|---|
| Hex D-type flip-flop architecture | Six independent, edge-triggered storage cells in one IC - reduces board space vs discrete solutions |
| Fully buffered inputs and outputs | Minimizes capacitive loading effects and improves noise immunity in dense PCB layouts |
| 100 MHz maximum clock frequency | Enables use in high-speed data acquisition and real-time control loops requiring sub-10 ns timing resolution |
| Asynchronous clear (CLR) | Allows immediate reset of entire register without waiting for next clock edge - critical for fault recovery |
| TTL-compatible voltage thresholds | VIH = 2 V, VIL = 0.8 V - interoperable with legacy 74xx, 74LS, and 74ALS logic without level-shifting |
| SOIC-16 RoHS-compliant packaging | Surface-mount form factor with NIPDAU lead finish and MSL Level-2 rating - suitable for automated assembly |
Applications
| Industrial PLC Register File | Test Equipment Pattern Generator |
|---|---|
|
Use Scenario: Storing and updating 6-bit control words in programmable logic controller I/O modules. IC Role / Device Role / Timing Role: Hex DFF acts as a synchronous latch bank, capturing parallel command bits on each scan cycle's clock edge. Use Value: Single-cycle write capability and guaranteed 100 MHz timing margin ensure deterministic response in hard real-time control loops. |
Use Scenario: Generating precise 6-bit stimulus sequences for digital IC functional testing. IC Role / Device Role / Timing Role: Configured as a 6-bit parallel-load shift register to produce repeatable test vectors under microcontroller control. Use Value: Fully buffered outputs drive multiple device-under-test inputs simultaneously with minimal skew (<9.5 ns). |
| Legacy System Data Buffer | Digital Instrumentation Latch |
|
Use Scenario: Interfacing between microprocessor data bus and slower peripheral devices in retro-computing hardware. IC Role / Device Role / Timing Role: Acts as a transparent data latch, holding bus values stable during peripheral access cycles. Use Value: Asynchronous CLR allows instant bus release on system reset, preventing contention during power-up sequencing. |
Use Scenario: Capturing sensor readings from parallel-output ADCs in benchtop multimeters and oscilloscopes. IC Role / Device Role / Timing Role: Synchronizes analog-to-digital conversion results into the instrument's digital processing pipeline. Use Value: 20 mA output drive supports direct connection to FPGA or MCU GPIO without external drivers. |
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 |
|---|---|---|---|
| SN74ALS174DR | ALS-family variant: lower speed (50 MHz max), reduced ICC (19 mA vs 45 mA), higher VOL (0.4 V @ 4 mA) | Lower power consumption but insufficient for >50 MHz clock domains; not drop-in for AS-timing-critical designs | Select SN74ALS174DR only where timing slack exceeds 2× and static power is prioritized over speed. |
| SN74AS174N | PDIP-16 through-hole package; identical electrical specs and timing; no RoHS exemption; MSL-unrated | Requires manual or wave soldering; unsuitable for high-density SMT production; same functional behavior | Choose SN74AS174N for prototyping, repair, or legacy through-hole systems where SOIC rework is impractical. |
Compared with SN74ALS174DR and SN74AS174N, the SN74AS174DR delivers the highest clock rate and lowest propagation delay in a RoHS-compliant, reflow-ready SOIC package - making it optimal for new SMT-based industrial designs demanding both speed and manufacturability.
Availability
SN74AS174DR is available at Aetrix Electronics and suitable for industrial control systems, test equipment development, and digital instrumentation requiring stable component supply across extended production lifecycles.
Supply support for SN74AS174DR 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 for industrial, automotive, and communications markets.
The SN74AS174DR belongs to TI's legacy 74AS logic family, designed specifically for high-speed, noise-immune digital register and storage applications in commercial-temperature environments.
FAQ
What is the maximum clock frequency supported by the SN74AS174DR?
The SN74AS174DR supports a maximum clock frequency of 100 MHz under recommended operating conditions (VCC = 4.5–5.5 V, TA = 0°C to 70°C, CL = 50 pF). This value is characterized and production-tested per TI's SDAS207E datasheet, enabling reliable operation in high-speed synchronous logic designs.
Does the SN74AS174DR have complementary (Q and Q̅) outputs?
No, the SN74AS174DR provides only true (Q) outputs - it is a hex D-type flip-flop with single-rail outputs. Complementary outputs are available only in the 'AS175B variant (quad DFF), not in the 'AS174 family including SN74AS174DR.
What are the correct termination requirements for unused inputs on the SN74AS174DR?
All unused inputs on the SN74AS174DR - including D inputs, CLK, and CLR - must be held at a valid logic level: either tied to VCC (for logic high) or GND (for logic low). Floating inputs may cause increased ICC, erratic switching, or damage due to TTL input structure sensitivity.
Is the SN74AS174DR pin-compatible with the SN74ALS174DR?
Yes, the SN74AS174DR and SN74ALS174DR share identical pinout, package (SOIC-16), and terminal functions. However, they are not functionally interchangeable without timing validation: SN74AS174DR offers double the clock speed (100 MHz vs 50 MHz) and faster propagation delays.
What is the meaning of "NC" on pins 3 and 11 of the SN74AS174DR?
"NC" stands for "No internal connection." Pins 3 and 11 of the SN74AS174DR have no bond wire or internal silicon connection. They must remain unconnected in the PCB layout - neither routed nor terminated - to avoid parasitic coupling or mechanical stress on the die.
SN74AS174DR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74AS
- Package/Case:
- 16-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Function:
- Master Reset
- Type:
- D-Type
- Output Type:
- Tri-State, Non-Inverted
- Number of Elements:
- 1
- Number of Bits per Element:
- 6
- Clock Frequency:
- 100 MHz
- Max Propagation Delay @ V, Max CL:
- 10ns @ 5V, 50pF
- Trigger Type:
- Positive Edge
- Current - Output High, Low:
- 2mA, 20mA
- Voltage - Supply:
- 4.5V ~ 5.5V
- Current - Quiescent (Iq):
- 45 mA
- Input Capacitance:
- -
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-SOIC
SN74AS174DR FAQ
1.How can I place an order for SN74AS174DR through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74AS174DR 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 SN74AS174DR reliable?
The price and inventory of SN74AS174DR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74AS174DR is usually 5 days.
3.What payment methods are accepted for SN74AS174DR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74AS174DR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74AS174DR?
SN74AS174DR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74AS174DR 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 SN74AS174DR?
For technical support, including SN74AS174DR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74AS174DR requirements.
6.How does Aetrix verify that SN74AS174DR is sourced from the original manufacturer or authorized distributors?
All SN74AS174DR 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 SN74AS174DR meets industry standards.
7.What is the process for return or replacement of SN74AS174DR?
All SN74AS174DR units undergo pre-shipment inspection (PSI). If there is an issue with SN74AS174DR, 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 SN74AS174DR part is unused and in its original packaging.
Return procedure for SN74AS174DR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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