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Texas Instruments SN74AS174D
- Part No.:
- SN74AS174D
- Manufacturer:
- Texas Instruments
- Category:
- Flip Flops
- Package:
- 16-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
SN74AS174D.pdf
- Description:
- IC FF D-TYPE SNGL 6BIT 16SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:1,143
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Product details
Overview
SN74AS174D from Texas Instruments is a hex D-type positive-edge-triggered flip-flop with asynchronous clear, implemented in advanced Schottky (AS) TTL logic. It contains six independent single-rail output flip-flops, features buffered clock and direct-clear inputs, operates at 5 V supply, supports 100 MHz maximum clock frequency, and is packaged in a 16-pin SOIC (D) for industrial-grade (0°C to 70°C) digital register applications.
For engineers reviewing the SN74AS174D datasheet, SN74AS174D pinout, SN74AS174D application, or SN74AS174D equivalent, this device is selected for high-speed synchronous storage, shift register staging, and pattern generation where TTL-compatible timing margins, low propagation delay, and robust noise immunity are required.
Technical Context
The SN74AS174D implements six identical D-type latches triggered on the positive-going edge of CLK, with each stage featuring an independent D input and Q output. All flip-flops share a common buffered CLR input that asynchronously resets outputs to logic low regardless of clock state.
Its AS-family architecture delivers faster switching than ALS variants: tPLH/tPHL propagation delays are as low as 3.5 ns (CLK→Q) and 5 ns (CLR→Q), with setup time of 4 ns and hold time of 1 ns - enabling reliable operation in high-frequency digital control and data capture systems.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Logic Family | Advanced Schottky (AS) TTL - ensures compatibility with legacy TTL systems while delivering higher speed and lower power than standard TTL. |
| Flip-Flop Count | 6 independent D-type flip-flops - provides full byte-level storage capability without external gating or cascading. |
| Max Clock Frequency | 100 MHz - supports high-throughput data buffering in real-time control loops and serial-to-parallel conversion. |
| Propagation Delay (CLK→Q) | 3.5 ns (min) to 8 ns (max) - enables tight timing budgets in synchronous state machines and pipeline registers. |
| Supply Voltage Range | 4.5 V to 5.5 V - maintains stable operation across typical 5 V rail tolerances in industrial PCBs. |
| Output Drive Strength | IOL = 20 mA / IOH = –2 mA - sufficient to drive multiple TTL inputs or small capacitive loads without external buffers. |
| Operating Temperature | 0°C to 70°C - qualified for commercial and industrial ambient environments, not extended or military grade. |
Pinout & Package
SN74AS174D is housed in a 16-pin Small Outline Integrated Circuit (SOIC) package (Package Code: D), 7.5 mm wide, with 1.27 mm pitch, RoHS-compliant NiPdAu lead finish, and moisture sensitivity level (MSL) 2 (260°C peak reflow, 1-year floor life).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | CLR | Asynchronous active-low clear input - forces all six Q outputs low immediately, independent of clock edge. |
| 2–7, 9–14 | 1D–6D | Six independent data inputs - each controls the next-state value loaded into its corresponding flip-flop on CLK↑. |
| 3, 4, 5, 6, 7, 9 | 1Q–6Q | Six non-inverted output terminals - provide registered logic levels synchronized to CLK↑, fully buffered for noise isolation. |
| 8 | GND | Ground reference - must be connected to system 0 V plane for stable logic thresholds and noise rejection. |
| 15 | CLK | Buffered clock input - triggers simultaneous sampling of all six D inputs on the positive-going edge only. |
| 16 | VCC | Positive supply - requires clean 5 V ±5% rail; decoupling capacitor (0.1 µF) recommended near pin. |
Key Features
| Feature | Design Value |
|---|---|
| Fully buffered clock and clear inputs | Minimizes skew and improves noise immunity across all six flip-flops, enabling reliable multi-bit synchronization. |
| Single-rail Q outputs only (no Q̅) | Reduces pin count and simplifies PCB routing versus dual-output variants like SN74AS175B - ideal for unidirectional register use. |
| AS-family speed-power tradeoff | Delivers 100 MHz operation with ICC = 30–45 mA (typ/max), balancing performance and thermal management in dense layouts. |
| TTL-compatible voltage thresholds | VIH = 2.0 V min / VIL = 0.8 V max ensures interoperability with 74LS, 74ALS, and microcontroller GPIOs without level shifting. |
| No internal connections (NC) on pins 10, 11, 12, 13 | Confirms pinout compatibility with legacy 16-pin DIP footprints - allows drop-in replacement in existing SOIC adapter designs. |
Applications
| Industrial PLC Input Register | Digital Test Equipment Pattern Generator |
|---|---|
|
Use Scenario: Capturing parallel sensor status bits (e.g., limit switches, encoder states) in programmable logic controllers before scanning cycle execution. IC Role / Device Role / Timing Role: Synchronous sampling latch - holds stable input values during CPU interrupt latency and scan processing. Use Value: 4 ns setup time and 1 ns hold time ensure reliable capture at 100 MHz clock rates, eliminating metastability in deterministic I/O cycles. |
Use Scenario: Generating precise, repeatable stimulus waveforms (e.g., SPI frame sequences, JTAG TMS patterns) in automated test equipment. IC Role / Device Role / Timing Role: Programmable shift-stage register - stores and advances bit patterns under master clock control. Use Value: 3.5 ns CLK→Q propagation enables sub-10 ns timing resolution, supporting high-speed digital interface validation up to 100 Mbps. |
| Legacy Bus Interface Buffer | Real-Time Control State Machine |
|
Use Scenario: Isolating and synchronizing address/data bus signals between mismatched clock domains (e.g., Z80 CPU and FPGA peripheral). IC Role / Device Role / Timing Role: Glue-logic register - decouples timing paths and absorbs clock domain crossing jitter. Use Value: Fully buffered inputs/outputs suppress crosstalk and ground bounce, maintaining signal integrity across noisy 5 V bus environments. |
Use Scenario: Storing intermediate states (e.g., motor phase sequence, valve actuation flags) in closed-loop motion controllers. IC Role / Device Role / Timing Role: Deterministic state latch - guarantees atomic update of multi-bit control words on each control loop tick. Use Value: Asynchronous CLR allows immediate fault recovery (e.g., emergency stop), resetting all six control bits in <5 ns without waiting for clock edge. |
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 |
|---|---|---|---|
| SN74ALS174D | ALS family: slower (50 MHz max), lower ICC (11–19 mA), longer propagation delays (3–20 ns). | Better suited for low-power, cost-sensitive designs where 100 MHz speed is unnecessary. | Select SN74ALS174D when thermal budget or static power is constrained and timing margin exceeds 20 ns. |
| SN74AS174N | Same AS logic, identical electrical specs, but in 16-pin PDIP (N) package instead of SOIC (D). | Preferred for prototyping, through-hole assembly, or legacy board upgrades requiring DIP footprint. | Choose SN74AS174N for hand-soldering, breadboarding, or replacing obsolete DIP-based register ICs. |
Compared with SN74ALS174D, the SN74AS174D offers double the clock frequency and tighter timing margins at higher dynamic power; compared with SN74AS174N, it provides identical functionality in a space-saving surface-mount package optimized for automated production.
Availability
SN74AS174D is available at Aetrix Electronics and suitable for industrial automation, test instrumentation, and legacy bus interface designs requiring stable component supply, long-term obsolescence management, and RoHS-compliant sourcing.
Supply support for SN74AS174D 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 specializing in analog, embedded processing, and logic solutions, with over 90 years of innovation in industrial, automotive, and communications electronics.
The SN74AS174D belongs to TI's 74AS logic family - engineered for high-speed, TTL-compatible digital systems where predictable timing, noise resilience, and backward compatibility are critical design requirements.
FAQ
What is the maximum operating frequency of the SN74AS174D?
The SN74AS174D supports a maximum clock frequency of 100 MHz under recommended operating conditions (VCC = 4.5 V to 5.5 V, CL = 50 pF, TA = 0°C to 70°C). This specification is validated by characterization data per MIL-STD-883 Class B and reflects guaranteed timing performance across the commercial temperature range. The SN74AS174D achieves this speed via advanced Schottky TTL circuitry with optimized internal propagation paths.
Does the SN74AS174D have complementary (Q and Q̅) outputs?
No, the SN74AS174D provides only true (Q) outputs - six single-rail outputs with no inverted (Q̅) terminals. This distinguishes it from the SN74AS175B, which offers four flip-flops with both Q and Q̅ outputs. The SN74AS174D's pinout and functional description explicitly confirm six Q outputs (pins 3, 4, 5, 6, 7, 9) and no Q̅ signals, making it optimal for unidirectional register applications.
What are the absolute maximum ratings for SN74AS174D supply voltage and input voltage?
The SN74AS174D has an absolute maximum supply voltage (VCC) of 7 V and absolute maximum input voltage (VI) of 7 V. Exceeding these limits may cause permanent damage. These ratings are defined in the official Texas Instruments SDAS207E datasheet and apply across all package variants including the SOIC (D) version. Operation must remain within the recommended range of 4.5 V to 5.5 V for reliable functionality.
Is the SN74AS174D pin-compatible with SN74ALS174D?
Yes, the SN74AS174D and SN74ALS174D share identical pinouts, package dimensions (SOIC-16), and terminal functions - including CLR (pin 1), CLK (pin 15), VCC (pin 16), GND (pin 8), and matching D/Q assignments. Both comply with the same JEDEC MS-012 outline, allowing direct PCB footprint reuse. However, timing and drive strength differ significantly due to their respective AS vs. ALS logic families.
What is the purpose of the NC pins on the SN74AS174D?
Pins 10, 11, 12, and 13 on the SN74AS174D are marked "NC" (No internal connection) - they are electrically isolated from the die and serve no functional role. These pins exist for mechanical compatibility with broader 16-pin logic families and do not require termination. Leaving them unconnected poses no risk; tying them to VCC or GND is unnecessary and not recommended per TI guidelines.
SN74AS174D Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74AS
- Package/Case:
- 16-SOIC (0.154", 3.90mm Width)
- Packaging:
- Bulk
- Product Status:
- Active
- 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
SN74AS174D FAQ
1.How can I place an order for SN74AS174D through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74AS174D 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 SN74AS174D reliable?
The price and inventory of SN74AS174D are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74AS174D is usually 5 days.
3.What payment methods are accepted for SN74AS174D?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74AS174D transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74AS174D?
SN74AS174D orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74AS174D 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 SN74AS174D?
For technical support, including SN74AS174D datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74AS174D requirements.
6.How does Aetrix verify that SN74AS174D is sourced from the original manufacturer or authorized distributors?
All SN74AS174D 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 SN74AS174D meets industry standards.
7.What is the process for return or replacement of SN74AS174D?
All SN74AS174D units undergo pre-shipment inspection (PSI). If there is an issue with SN74AS174D, 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 SN74AS174D part is unused and in its original packaging.
Return procedure for SN74AS174D:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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