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Texas Instruments SN74ALS874BDWRE4
- Part No.:
- SN74ALS874BDWRE4
- Manufacturer:
- Texas Instruments
- Category:
- Flip Flops
- Package:
- 24-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
SN74ALS874BDWRE4.pdf
- Description:
- IC FF D-TYPE DUAL 4BIT 20SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:3,054
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Product details
Overview
SN74ALS874BDWRE4 from Texas Instruments is a dual 4-bit D-type edge-triggered flip-flop with 3-state noninverting outputs, designed as a bus-oriented register driver. It features asynchronous clear (CLR), true logic outputs, 24-pin SOIC (DW) package, 30 MHz max clock frequency, and 24 mA low-level output drive-enabling direct TTL/LS bus interfacing in industrial control backplanes and legacy data acquisition systems.
For engineers reviewing the SN74ALS874BDWRE4 datasheet, SN74ALS874BDWRE4 pinout, SN74ALS874BDWRE4 application, or SN74ALS874BDWRE4 equivalent, key selection criteria include bus-driver timing (tPLH/tPHL ≤14 ns), 3-state enable/disable performance (tPZH/tPLZ ≤18 ns), rail-to-rail 5 V operation, and compatibility with ALS logic families in space-constrained PCB layouts requiring high fan-out and bidirectional bus isolation.
Technical Context
This device implements two independent 4-bit D-type registers, each with edge-triggered latching on CLK↑ and asynchronous active-low CLR. The 3-state outputs are controlled by separate OE inputs per register, enabling independent bus arbitration without external gating logic.
It operates strictly within 4.5–5.5 V supply range and is characterized for 0°C to 70°C ambient. Its ALS-family propagation delays (e.g., tPHL = 4–14 ns) and output drive (IOL = 24 mA) are optimized for noise-immune, high-speed TTL-compatible bus loading-distinct from AS-series variants (e.g., SN74AS874) which offer faster timing but higher ICC and tighter VIH/VIL thresholds.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Logic Family | Advanced Low-Power Schottky (ALS), fully compatible with TTL input/output voltage thresholds and drive strength |
| Max Clock Frequency | 30 MHz - supports synchronous data capture at 33.3 ns period in bus register applications |
| Output Drive (IOL) | 24 mA - directly drives 10+ standard TTL loads or 20+ LS-TTL loads without buffer amplification |
| Propagation Delay (tPHL) | 4–14 ns - ensures sub-15 ns register-to-bus latency critical for real-time I/O port handshaking |
| 3-State Enable Time (tPZH) | 2–10 ns - enables fast bus release for time-multiplexed peripheral access in shared-data-path architectures |
| Supply Voltage Range | 4.5 V to 5.5 V - accommodates nominal 5 V rails with ±10% tolerance, including aging and ripple margins |
| Operating Temperature | 0°C to 70°C - qualified for commercial-grade embedded systems, not extended or military temperature ranges |
Pinout & Package
SN74ALS874BDWRE4 uses a 24-pin SOIC (DW) package with 300-mil width, gull-wing leads, and JEDEC MO-058 AB compliance. Pin 1 is located in Quadrant Q1 per tape-and-reel orientation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1CLR, 2CLR | Asynchronous Clear Input (active-low) | Resets corresponding 4-bit register independently of clock; overrides CLK and D inputs |
| 1OE, 2OE | Output Enable Input (active-low) | Controls 3-state output drivers for respective register; high = high-impedance bus release |
| 1CLK, 2CLK | Clock Input (positive-edge triggered) | Latches data from D inputs on rising edge; no internal synchronization or metastability hardening |
| 1D1–1D4, 2D1–2D4 | Data Inputs | Parallel 4-bit input per register; sampled only on CLK↑ when CLR is inactive |
| 1Q1–1Q4, 2Q1–2Q4 | Noninverting Registered Outputs | True logic outputs reflecting latched D values; driven only when OE is low |
| VCC, GND | Power Supply Pins | Single 5 V supply; requires local 0.1 µF ceramic decoupling per package per TI layout guidelines |
Key Features
| Feature | Design Value |
|---|---|
| Dual independent 4-bit registers | Enables two separate 4-bit data paths (e.g., address/data latching) on one IC, reducing board count and routing complexity |
| Bus-structured pinout | Minimizes trace crossovers in dense PCB layouts; groups related signals (D/Q/OE/CLK per register) for clean routing |
| 3-state outputs with separate OE | Allows dynamic bus sharing between multiple devices without external bus transceivers or direction control logic |
| Asynchronous clear per register | Permits selective reset of one register while preserving state in the other-critical for multi-channel I/O port management |
| ALS logic family compatibility | Guarantees interoperability with legacy 74ALS, 74LS, and 74F systems without level-shifting or timing recalculations |
Applications
| Industrial Backplane Bus Interface | Legacy Data Acquisition System |
|---|---|
|
Use Scenario: Isolating microcontroller data bus from multiple sensor interface cards in a modular PLC rack. IC Role / Device Role / Timing Role: Dual register buffers data transfers between CPU and peripheral modules; 3-state OE enables time-sliced bus arbitration. Use Value: Eliminates need for discrete bus transceivers; 24 mA drive sustains signal integrity across 12-inch backplane traces at 30 MHz. |
Use Scenario: Capturing parallel 8-bit ADC outputs in a 1980s-era test instrument with fixed 5 V TTL architecture. IC Role / Device Role / Timing Role: Latching sampled analog-to-digital conversion results into synchronized 4-bit chunks before serial readout. Use Value: Asynchronous CLR allows immediate channel reset after overflow detection; ALS timing matches legacy controller clock budgets. |
| Programmable Logic Controller I/O Port | Embedded System Address Latch |
|
Use Scenario: Providing configurable digital I/O expansion via ISA-style expansion slots in ruggedized control hardware. IC Role / Device Role / Timing Role: Acting as bidirectional I/O port register with independent OE control per 4-bit nibble for handshake signaling. Use Value: True outputs and bus-structured pinout simplify PCB layout; 14 ns tPHL meets 70 ns minimum strobe hold requirements. |
Use Scenario: Latching upper/lower address bytes during multiplexed address/data bus cycles in 8086-based designs. IC Role / Device Role / Timing Role: Holding address bits stable during memory or I/O read/write cycles while data bus transitions. Use Value: Dual-register structure permits simultaneous latch of A0–A3 and A4–A7; 3-state outputs prevent bus contention during data phase. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar dual 4-bit registered bus driver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74ALS874BDWR | Same die, identical electrical specs, RoHS-compliant NIPDAU finish vs. E4's legacy finish; same DW package and marking "ALS874B" | No functional difference; suitable for new designs requiring RoHS compliance and modern assembly processes | Select SN74ALS874BDWR for new production; SN74ALS874BDWRE4 remains viable for legacy repair or obsolescence mitigation where E4 marking is specified |
| SN74AS874DW | Faster timing (125 MHz fmax, 8.5 ns tPLH), higher ICC (133 mA), stricter VIH/VIL (2.0 V/0.8 V), and 48 mA IOL | Better suited for high-speed bus extensions but incompatible with ALS/LS fan-out budgets and power budgets | Choose SN74AS874DW only if system demands sub-10 ns register latency and can support higher supply current and tighter input thresholds |
Compared with SN74ALS874BDWRE4, SN74ALS874BDWR offers identical functionality with updated environmental compliance, while SN74AS874DW trades power efficiency and legacy compatibility for raw speed-making the former a drop-in replacement and the latter a redesign-dependent upgrade.
Availability
SN74ALS874BDWRE4 is available at Aetrix Electronics and suitable for industrial backplane interfaces, legacy data acquisition systems, programmable logic controller I/O ports, and embedded system address latching requiring stable component supply across long-lifecycle deployments.
Supply support for SN74ALS874BDWRE4 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.
SN74ALS874BDWRE4 belongs to TI's legacy 74ALS logic family, engineered for high-speed, low-power bus interfacing in 5 V TTL-compatible systems-targeting reliability-critical industrial control and instrumentation where backward compatibility and proven field performance are essential.
FAQ
What is the function of the 1CLR and 2CLR pins on the SN74ALS874BDWRE4?
The 1CLR and 2CLR pins are active-low asynchronous clear inputs that independently reset the first and second 4-bit registers of the SN74ALS874BDWRE4. When pulled low, they force all Q outputs in the respective register to logic low regardless of clock or data inputs-enabling immediate, clock-independent state clearing for fault recovery or initialization sequences in the SN74ALS874BDWRE4.
Does the SN74ALS874BDWRE4 support 3.3 V operation?
No, the SN74ALS874BDWRE4 is specified only for 4.5 V to 5.5 V supply operation and is not 3.3 V tolerant. Its input thresholds (VIH = 2.0 V, VIL = 0.8 V) and output drive characteristics are optimized for 5 V TTL/ALS systems. Applying 3.3 V to VCC will result in undefined behavior, insufficient noise margin, or failure to meet timing specifications for the SN74ALS874BDWRE4.
How does the SN74ALS874BDWRE4 differ from the SN74ALS876A?
The SN74ALS874BDWRE4 features asynchronous clear (CLR) and noninverting Q outputs, whereas the SN74ALS876A uses preset (PRE) and inverting Q outputs. Their function tables, timing parameters, and control logic are distinct: SN74ALS874BDWRE4 resets outputs low on CLR, while SN74ALS876A forces outputs low on PRE. They are not functionally interchangeable without circuit redesign for the SN74ALS874BDWRE4.
What is the maximum capacitive load the SN74ALS874BDWRE4 can drive on its outputs?
The SN74ALS874BDWRE4 switching characteristics are characterized with CL = 50 pF, and its output drive capability (24 mA IOL) supports typical PCB trace capacitance plus up to ~3–5 standard TTL inputs. Driving >75 pF may degrade tPLH/tPHL beyond 14 ns and increase ground bounce; TI recommends limiting total load to 50 pF unless validated with actual board parasitics for the SN74ALS874BDWRE4.
Is the SN74ALS874BDWRE4 pin-compatible with the SN74AS874DW?
Yes, the SN74ALS874BDWRE4 and SN74AS874DW share identical 24-pin SOIC (DW) packaging and pinout-including matching assignments for CLR, OE, CLK, D, Q, VCC, and GND. However, they are not functionally or electrically interchangeable due to differing timing, drive strength, and supply current; substituting them requires full system validation for the SN74ALS874BDWRE4.
SN74ALS874BDWRE4 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74ALS
- Package/Case:
- 24-SOIC (0.295", 7.50mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Discontinued at Digi-Key
- Function:
- Master Reset
- Type:
- D-Type
- Output Type:
- Tri-State, Non-Inverted
- Number of Elements:
- 2
- Number of Bits per Element:
- 4
- Clock Frequency:
- 30 MHz
- Max Propagation Delay @ V, Max CL:
- 14ns @ 5V, 50pF
- Trigger Type:
- Positive Edge
- Current - Output High, Low:
- 2.6mA, 24mA
- Voltage - Supply:
- 4.5V ~ 5.5V
- Current - Quiescent (Iq):
- 21 mA
- Input Capacitance:
- -
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 24-SOIC
SN74ALS874BDWRE4 FAQ
1.How can I place an order for SN74ALS874BDWRE4 through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74ALS874BDWRE4 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 SN74ALS874BDWRE4 reliable?
The price and inventory of SN74ALS874BDWRE4 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74ALS874BDWRE4 is usually 5 days.
3.What payment methods are accepted for SN74ALS874BDWRE4?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74ALS874BDWRE4 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74ALS874BDWRE4?
SN74ALS874BDWRE4 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74ALS874BDWRE4 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 SN74ALS874BDWRE4?
For technical support, including SN74ALS874BDWRE4 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74ALS874BDWRE4 requirements.
6.How does Aetrix verify that SN74ALS874BDWRE4 is sourced from the original manufacturer or authorized distributors?
All SN74ALS874BDWRE4 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 SN74ALS874BDWRE4 meets industry standards.
7.What is the process for return or replacement of SN74ALS874BDWRE4?
All SN74ALS874BDWRE4 units undergo pre-shipment inspection (PSI). If there is an issue with SN74ALS874BDWRE4, 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 SN74ALS874BDWRE4 part is unused and in its original packaging.
Return procedure for SN74ALS874BDWRE4:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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