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Texas Instruments SN74ALS874BDWR
- Part No.:
- SN74ALS874BDWR
- Manufacturer:
- Texas Instruments
- Category:
- Flip Flops
- Package:
- 24-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
SN74ALS874BDWR.pdf
- Description:
- IC FF D-TYPE DUAL 4BIT 20SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:2,601
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Product details
Overview
SN74ALS874BDWR from Texas Instruments is a dual 4-bit D-type edge-triggered flip-flop with 3-state bus-driver outputs, asynchronous clear (CLR), true logic polarity, and bus-structured pinout. It operates from 0°C to 70°C at 4.5–5.5 V, delivers 24 mA low-level output current, and supports up to 30 MHz clock frequency - ideal for bidirectional bus interfacing in industrial control backplanes.
For engineers reviewing the SN74ALS874BDWR datasheet, SN74ALS874BDWR pinout, SN74ALS874BDWR application, or SN74ALS874BDWR equivalent, key selection criteria include its 24-pin SOIC (DW) package, 3-state output enable timing (tPZH/tPLZ ≤ 18 ns), dual independent clear control per 4-bit section, and compatibility with ALS logic families in legacy TTL-based data path designs.
Technical Context
This device implements two independent 4-bit D-type registers, each with separate clock (CLK), clear (CLR), and output-enable (OE) inputs. Data is latched on the low-to-high transition of CLK, and outputs enter high-impedance state when OE is high.
The SN74ALS874BDWR uses bipolar ALS (Advanced Low-Power Schottky) technology, delivering higher speed and lower power than standard LS logic. Its 3-state outputs drive bus lines directly without external pull-ups, and the bus-structured pinout minimizes trace skew in parallel data paths.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Logic Family | ALS (Advanced Low-Power Schottky) - enables 30 MHz operation with 21 mA typical ICC at 5.5 V |
| Supply Voltage Range | 4.5 V to 5.5 V - compatible with standard 5 V TTL systems; absolute max 7 V |
| Max Clock Frequency | 30 MHz - supports high-speed register transfer in legacy bus architectures |
| Output Drive | IOL = 24 mA / IOH = −2.6 mA - sufficient to drive 50 Ω transmission lines or multiple TTL inputs |
| Propagation Delay | tPLH/tPHL ≤ 14 ns (CLK to Q) - ensures tight timing margins in synchronous data capture |
| 3-State Enable/Disable | tPZH ≤ 10 ns, tPLZ ≤ 12 ns - fast bus turnaround critical for bidirectional data arbitration |
| Operating Temperature | 0°C to 70°C - commercial-grade rating suitable for industrial embedded control cabinets |
Pinout & Package
SN74ALS874BDWR is housed in a 24-pin SOIC (DW) package - 7.5 mm wide, 15.4 mm long, 2.38 mm height, RoHS-compliant NiPdAu lead finish, MSL Level-1 (unlimited reflow).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1CLR, 2CLR | Asynchronous Clear Input (active-low) | Resets corresponding 4-bit register independently of clock; overrides data and OE |
| 1OE, 2OE | Output Enable Input (active-low) | Controls 3-state output drivers for each 4-bit section; high = high-Z |
| 1CLK, 2CLK | Clock Input (positive-edge triggered) | Latches data from D inputs on rising edge; no internal synchronization |
| 1D1–1D4, 2D1–2D4 | Data Inputs | Parallel 4-bit input per register section; sampled only on active CLK edge |
| 1Q1–1Q4, 2Q1–2Q4 | Noninverting Registered Outputs | True (noninverted) Q outputs; tri-stated when respective OE is high |
| VCC, GND | Power Supply Pins | Single 5 V supply; requires local 0.1 µF ceramic decoupling per VCC pin |
Key Features
| Feature | Design Value |
|---|---|
| Dual independent 4-bit registers | Enables two separate 4-bit data paths (e.g., address/data separation) without inter-register timing dependency |
| Bus-structured pinout | Minimizes PCB trace length mismatch between D/Q signals - reduces skew in parallel bus implementations |
| 3-state outputs with fast enable/disable | tPHZ ≤ 10 ns and tPLZ ≤ 12 ns allow sub-20 ns bus release - essential for time-multiplexed shared-bus protocols |
| Asynchronous clear per section | Permits selective reset of one register bank without disturbing the other - improves system-level fault recovery |
| ALS logic family performance | Delivers 30 MHz operation with 21 mA typical ICC - 3× faster than LS with comparable power vs. AS |
Applications
| Industrial Backplane Bus Interface | Legacy Microprocessor I/O Port Expansion |
|---|---|
|
Use Scenario: Interfacing microcontroller GPIOs to a 8-bit parallel backplane in programmable logic controllers (PLCs). IC Role / Device Role / Timing Role: Acts as a buffered, registered I/O port expander with independent clear per nibble - synchronizing peripheral data to system clock domain. Use Value: Enables deterministic setup/hold timing (tsu = 15 ns, th = 4 ns) and eliminates bus contention via 3-state control during read-modify-write cycles. |
Use Scenario: Adding synchronous latch capability to Z80 or 8085-based development systems for memory-mapped peripheral registers. IC Role / Device Role / Timing Role: Provides edge-triggered storage for control/status words with direct bus connection - eliminating need for discrete buffers or glue logic. Use Value: Supports 30 MHz clocking and 24 mA drive strength to meet TTL fan-out requirements without external drivers. |
| Test Equipment Digital Pattern Generator | Avionics Data Acquisition Module |
|
Use Scenario: Generating synchronized digital stimulus waveforms in automated test equipment (ATE) pattern generators. IC Role / Device Role / Timing Role: Serves as a deterministic, low-skew 8-bit pattern register - latching test vectors on precise clock edges before driving bus lines. Use Value: Bus-structured pinout and matched propagation delays (<14 ns) ensure <1 ns inter-bit skew across all 8 outputs. |
Use Scenario: Capturing sensor data from analog-to-digital converters in airborne flight control subsystems. IC Role / Device Role / Timing Role: Functions as a hardened, registered interface between ADC parallel outputs and MIL-STD-1553 or ARINC-429 bus controllers. Use Value: ALS process provides radiation-tolerant characteristics and stable operation over extended temperature range (0°C to 70°C) required for avionics enclosures. |
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 |
|---|---|---|---|
| SN74AS874DW | Faster (125 MHz max clock), higher drive (IOL = 48 mA), but higher ICC (133 mA typ) and tighter VIH/VIL thresholds | Better suited for high-speed test instrumentation; less tolerant of marginal signal integrity or aging TTL inputs | Choose SN74AS874DW only if >30 MHz operation is required and power budget allows +500% ICC increase |
| SN74ALS876ADW | Inverting Q outputs, preset (PRE) instead of clear (CLR), same timing and drive specs | Required where active-high preset logic is used in system control architecture (e.g., legacy minicomputer I/O boards) | Select SN74ALS876ADW only when inverting output polarity and PRE functionality match existing board design constraints |
Compared with SN74ALS874BDWR, SN74AS874DW trades power efficiency for speed, while SN74ALS876ADW maintains identical ALS performance but swaps clear for preset and inverts outputs - neither is pin-compatible, requiring PCB layout changes and logic inversion in firmware or upstream gates.
Availability
SN74ALS874BDWR is available at Aetrix Electronics and suitable for industrial control backplanes, legacy microprocessor I/O expansion, and test equipment digital pattern generation requiring stable component supply and long-term obsolescence management.
Supply support for SN74ALS874BDWR 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, automotive, and aerospace heritage.
The SN74ALS874BDWR belongs to TI's legacy ALS logic product line - engineered for high-reliability, medium-speed digital interfacing in systems where backward compatibility with TTL and low static power are critical design priorities.
FAQ
What logic family does SN74ALS874BDWR belong to, and how does it compare to standard LS logic?
SN74ALS874BDWR belongs to the Advanced Low-Power Schottky (ALS) logic family. Compared to standard LS, it offers approximately 3× higher speed (30 MHz vs. ~10 MHz) and ~20% lower power consumption at the same operating frequency. Its VIH/VIL thresholds (2.0 V / 0.8 V) and 24 mA output drive maintain full TTL compatibility while enabling tighter timing margins in SN74ALS874BDWR-based designs.
Does SN74ALS874BDWR support independent clocking for each 4-bit section?
No. SN74ALS874BDWR has two separate clock inputs - 1CLK and 2CLK - allowing fully independent clocking of the first and second 4-bit register sections. This enables asynchronous data capture from two different sources or domains without cross-section timing dependency, a capability confirmed in the function table and logic diagram of the SN74ALS874BDWR datasheet.
What is the maximum capacitive load SN74ALS874BDWR can drive while maintaining specified timing?
SN74ALS874BDWR switching characteristics (tPLH, tPHL, tPZH, etc.) are characterized with CL = 50 pF, R1 = R2 = 500 Ω. Driving loads significantly above 50 pF will increase propagation and enable/disable delays beyond datasheet limits. For reliable 30 MHz operation, total net capacitance including trace and stubs must remain ≤50 pF - verified in the SN74ALS874BDWR switching characteristics table under recommended conditions.
Is SN74ALS874BDWR pin-compatible with SN74ALS876ADW?
No. Although both are 24-pin SOIC dual 4-bit registers, SN74ALS874BDWR uses active-low CLR inputs and noninverting Q outputs, whereas SN74ALS876ADW uses active-low PRE inputs and inverting Q outputs. Pin functions differ at pins 1 (1CLR vs. 1PRE), 13 (2CLR vs. 2PRE), and all Q outputs (true vs. complemented), making them functionally incompatible without redesign.
What is the meaning of "bus-structured pinout" for SN74ALS874BDWR, and why does it matter?
"Bus-structured pinout" means SN74ALS874BDWR arranges related signals (e.g., 1D1–1D4, 1Q1–1Q4, 2D1–2D4, 2Q1–2Q4) in adjacent, sequential pin order - minimizing trace length variation across parallel data paths. This reduces inter-signal skew, which is critical for maintaining setup/hold timing in high-speed parallel buses. The physical layout is explicitly shown in the SN74ALS874BDWR DW package top-view diagram.
SN74ALS874BDWR 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:
- Active
- 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
SN74ALS874BDWR FAQ
1.How can I place an order for SN74ALS874BDWR through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74ALS874BDWR 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 SN74ALS874BDWR reliable?
The price and inventory of SN74ALS874BDWR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74ALS874BDWR is usually 5 days.
3.What payment methods are accepted for SN74ALS874BDWR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74ALS874BDWR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74ALS874BDWR?
SN74ALS874BDWR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74ALS874BDWR 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 SN74ALS874BDWR?
For technical support, including SN74ALS874BDWR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74ALS874BDWR requirements.
6.How does Aetrix verify that SN74ALS874BDWR is sourced from the original manufacturer or authorized distributors?
All SN74ALS874BDWR 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 SN74ALS874BDWR meets industry standards.
7.What is the process for return or replacement of SN74ALS874BDWR?
All SN74ALS874BDWR units undergo pre-shipment inspection (PSI). If there is an issue with SN74ALS874BDWR, 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 SN74ALS874BDWR part is unused and in its original packaging.
Return procedure for SN74ALS874BDWR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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