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Texas Instruments SN74AS4374BN
- Part No.:
- SN74AS4374BN
- Manufacturer:
- Texas Instruments
- Category:
- Flip Flops
- Package:
- 20-DIP (0.300", 7.62mm)
- Datasheet:
-
SN74AS4374BN.pdf
- Description:
- IC FF D-TYPE SNGL 8BIT 20DIP
- Quantity:
- Payment:
- Shipping:
Inventory:504
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Product details
Overview
SN74AS4374BN from Texas Instruments is an octal edge-triggered D-type dual-rank flip-flop with 3-state outputs in a 20-pin plastic DIP (N) package. It operates from 4.5 V to 5.5 V, supports up to 125 MHz clock frequency, delivers ±48 mA output drive, features 4 ns data setup time, and is rated for 0°C to 70°C industrial temperature range. It serves as a bus interface register in high-speed digital systems.
For engineers reviewing the SN74AS4374BN datasheet, SN74AS4374BN pinout, SN74AS4374BN application, or SN74AS4374BN equivalent, key selection criteria include dual-rank edge-triggering behavior, 3-state bus-driving capability, TTL-compatible input thresholds, guaranteed propagation delay under 8 ns, and compatibility with 5-V logic families in legacy computing and industrial control designs.
Technical Context
The SN74AS4374BN implements eight independent D-type flip-flops, each triggered on the second positive clock edge-enabling dual-rank synchronization where data presented at D inputs requires two CLK cycles to appear at Q outputs. Its 3-state outputs are controlled solely by OE, which does not affect internal storage or clocking behavior.
This device uses bipolar Schottky (AS) technology, delivering fast switching (tPLH/tPHL ≤ 8 ns), high current drive (IOL = 48 mA), and robust noise immunity (VIL = 0.8 V, VIH = 2 V). It is designed for direct connection to capacitive bus lines without external buffering.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Logic Family | AS (Advanced Schottky) TTL - enables high-speed operation with low power-delay product |
| Supply Voltage Range | 4.5 V to 5.5 V - compatible with standard 5-V TTL/CMOS mixed-signal systems |
| Max Clock Frequency | 125 MHz - supports high-throughput data latching in real-time control interfaces |
| Output Drive | IOL = 48 mA / IOH = –15 mA - drives heavy capacitive loads (e.g., >50 pF buses) directly |
| Propagation Delay | tPLH/tPHL ≤ 8 ns @ VCC = 4.5–5.5 V, CL = 50 pF - ensures timing closure in sub-10 ns critical paths |
| Setup/Hold Times | tsu = 4 ns, th = 1 ns - tight timing window demands precise clock/data alignment |
| Operating Temperature | 0°C to 70°C - qualified for commercial and industrial ambient environments |
Pinout & Package
SN74AS4374BN is housed in a 20-pin plastic DIP (300-mil) package (N suffix), with 0.1-inch lead spacing and through-hole mounting. Pin 10 is GND, pin 20 is VCC, and all I/O pins follow standard octal register layout.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1Q–8Q (pins 1–4, 6–9) | 3-State Output | Active-high buffered data outputs; high-impedance when OE = high |
| 1D–8D (pins 11–14, 16–19) | Data Input | Asynchronous D inputs synchronized to second rising CLK edge |
| CLK (pin 15) | Clock Input | Edge-triggered input controlling dual-rank latching sequence |
| OE (pin 10) | Output Enable | Active-low control; disables outputs without affecting internal state |
| VCC (pin 20) | Power Supply | +5 V supply rail for AS TTL core and output drivers |
| GND (pin 10) | Ground Reference | Common return path for logic and output current |
Key Features
| Feature | Design Value |
|---|---|
| Dual-rank edge triggering | Data at D inputs appears at Q outputs after exactly two CLK rising edges - enables pipeline staging and metastability mitigation |
| 3-State bus interface | OE-controlled high-impedance outputs allow shared-bus arbitration without external tri-state logic |
| High-current TTL outputs | 48 mA sink capability eliminates need for external bus drivers in dense backplane applications |
| Tight AC timing | 4 ns setup time and ≤8 ns propagation delay support 125 MHz system clocks with margin |
| Industrial temperature rating | 0°C to 70°C operation ensures reliability in non-automotive embedded control cabinets and test equipment |
Applications
| Computer Bus Interface | Industrial I/O Expansion |
|---|---|
Use Scenario: Interfacing microprocessor address/data buses to peripheral memory or I/O devices with load-matching requirements. IC Role / Device Role / Timing Role: Octal latch and bus driver providing synchronized, high-drive 3-state buffering between CPU and parallel peripherals. Use Value: Eliminates need for discrete buffer arrays while maintaining timing integrity at 125 MHz due to guaranteed tPLH ≤ 8 ns and 48 mA drive. | Use Scenario: Adding parallel digital I/O ports to PLC modules or motion controllers requiring deterministic signal capture. IC Role / Device Role / Timing Role: Dual-rank register capturing sensor or actuator status on second clock edge to suppress asynchronous glitches. Use Value: Dual-rank behavior reduces metastability risk in noisy factory environments where input signals may violate setup/hold windows. |
| Bidirectional Data Transceiver | Legacy System Buffering |
Use Scenario: Implementing half-duplex parallel communication between FPGA and microcontroller over shared 8-bit data lines. IC Role / Device Role / Timing Role: Direction-controlled 3-state register enabling bidirectional data flow using OE as direction select. Use Value: Single-device solution replaces discrete transceiver pairs; OE-independent internal storage retains data during bus turnaround. | Use Scenario: Replacing obsolete 74LS/74S-series octal latches in aging test equipment or avionics maintenance tools. IC Role / Device Role / Timing Role: Pin-compatible upgrade offering faster speed (125 MHz vs. 30 MHz), higher drive, and improved noise margins. Use Value: Extends service life of legacy hardware without PCB redesign-maintains same N-package footprint and pinout. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar octal D-type flip-flop applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74AS821N | Single-rank (not dual-rank); identical AS family specs, same 20-pin N package | Lacks second-edge latching - unsuitable for metastability-critical sampling but simpler for basic register use | Select when single-cycle latency is required and dual-rank behavior is unnecessary |
| SN74F374N | F-family (not AS); lower max frequency (100 MHz), weaker drive (IOL = 20 mA), same pinout | Higher power consumption and slower timing - acceptable only in cost-sensitive, lower-speed upgrades | Choose only if AS-speed and drive are not required and F-series inventory is available |
Compared with SN74AS4374BN, SN74AS821N removes dual-rank latency but retains full speed and drive, while SN74F374N trades performance for broader legacy compatibility and lower unit cost - neither is pin-compatible in function, though both share the 20-pin DIP mechanical form.
Availability
SN74AS4374BN is available at Aetrix Electronics and suitable for computer bus interface, industrial I/O expansion, bidirectional data transceiver, and legacy system buffering applications requiring stable component supply and long-term obsolescence management.
Supply support for SN74AS4374BN 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 solutions for industrial, automotive, and communications markets.
The SN74AS4374BN belongs to TI's legacy AS-series TTL logic family, engineered for high-speed, low-noise digital interfacing in systems where timing precision and bus-loading resilience are critical.
FAQ
What is the clocking behavior of the SN74AS4374BN?
The SN74AS4374BN uses dual-rank edge triggering: data present at the D inputs appears at the Q outputs only after the second rising edge of the CLK signal. This behavior is defined in the function table and distinguishes it from standard single-rank D flip-flops. The SN74AS4374BN does not respond to the first clock edge for output update - internal staging ensures two-cycle latency, which aids in synchronizing asynchronous inputs and reducing metastability risk in the SN74AS4374BN design.
Does the OE pin affect internal flip-flop operation in the SN74AS4374BN?
No - the OE (output enable) pin in the SN74AS4374BN controls only the 3-state output drivers and has no effect on internal storage or clocking behavior. Flip-flop states remain fully retained, and new data can be latched on subsequent CLK edges even while outputs are disabled (OE = high). This allows the SN74AS4374BN to maintain register integrity during bus contention or power management sequences without requiring re-latching.
What is the maximum capacitive load the SN74AS4374BN can drive reliably?
The SN74AS4374BN is characterized for CL = 50 pF in its switching specifications, with propagation delays and timing parameters guaranteed under that condition. Its 48 mA output sink capability supports heavier loads than standard TTL, but for reliable operation beyond 50 pF, layout practices (short traces, ground plane) and verification under actual board conditions are recommended. The SN74AS4374BN datasheet does not specify derating curves for higher capacitance, so system-level validation is advised when driving >50 pF.
Is the SN74AS4374BN compatible with 3.3-V logic systems?
No - the SN74AS4374BN is a 5-V-only TTL device with minimum VCC = 4.5 V and input thresholds (VIH = 2.0 V, VIL = 0.8 V) optimized for 5-V signaling. It is not 3.3-V tolerant: applying 3.3-V inputs risks marginal high-level recognition, and powering from 3.3 V will cause functional failure. Interfacing with 3.3-V systems requires level-shifting circuitry; the SN74AS4374BN must operate strictly within its 4.5–5.5 V supply range.
What package type does the SN74AS4374BN use, and is it RoHS-compliant?
The SN74AS4374BN uses a 20-pin plastic DIP (N) package with 300-mil width and through-hole leads. As a legacy device introduced in 1989 and last revised in 1995, it predates RoHS regulations and is not RoHS-compliant - it contains lead in solder and packaging materials. For RoHS-compliant alternatives, engineers should consider modern logic families (e.g., SN74LVC series) with equivalent functionality, though those require PCB redesign due to different packages and voltage domains.
SN74AS4374BN Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74AS
- Package/Case:
- 20-DIP (0.300", 7.62mm)
- Packaging:
- Tube
- Product Status:
- Obsolete
- Function:
- Standard
- Type:
- D-Type
- Output Type:
- Tri-State, Non-Inverted
- Number of Elements:
- 1
- Number of Bits per Element:
- 8
- Clock Frequency:
- 125 MHz
- Max Propagation Delay @ V, Max CL:
- 8ns @ 5V, 50pF
- Trigger Type:
- Positive Edge
- Current - Output High, Low:
- 15mA, 48mA
- Voltage - Supply:
- 4.5V ~ 5.5V
- Current - Quiescent (Iq):
- 150 mA
- Input Capacitance:
- -
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 20-PDIP
SN74AS4374BN FAQ
1.How can I place an order for SN74AS4374BN through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74AS4374BN 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 SN74AS4374BN reliable?
The price and inventory of SN74AS4374BN are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74AS4374BN is usually 5 days.
3.What payment methods are accepted for SN74AS4374BN?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74AS4374BN transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74AS4374BN?
SN74AS4374BN orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74AS4374BN 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 SN74AS4374BN?
For technical support, including SN74AS4374BN datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74AS4374BN requirements.
6.How does Aetrix verify that SN74AS4374BN is sourced from the original manufacturer or authorized distributors?
All SN74AS4374BN 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 SN74AS4374BN meets industry standards.
7.What is the process for return or replacement of SN74AS4374BN?
All SN74AS4374BN units undergo pre-shipment inspection (PSI). If there is an issue with SN74AS4374BN, 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 SN74AS4374BN part is unused and in its original packaging.
Return procedure for SN74AS4374BN:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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