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Texas Instruments 74ACT11821DWR
- Part No.:
- 74ACT11821DWR
- Manufacturer:
- Texas Instruments
- Package:
- -
- Datasheet:
-
74ACT11821DWR.pdf
- Description:
- BUS DRIVER, ACT SERIES, 10-BIT
- Quantity:
- Payment:
- Shipping:
Inventory:3,000
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Product details
Overview
74ACT11821DWR from Texas Instruments is a 10-bit bus-interface D-type flip-flop with 3-state outputs, designed for high-capacitance bus driving in address/data paths with parity. It operates at 5 V ±0.5 V, supports 125 MHz clock frequency, features ±24 mA output drive, and is rated for –40°C to 85°C industrial temperature range.
For engineers reviewing the 74ACT11821DWR datasheet, 74ACT11821DWR pinout, 74ACT11821DWR application, or 74ACT11821DWR equivalent, key selection criteria include 3-state bus interface capability, TTL-compatible inputs, flow-through pinout for PCB layout optimization, and latch-up immunity of 500 mA at 125°C.
Technical Context
This device implements ten independent edge-triggered D-type flip-flops, each synchronized on the positive clock transition. Its buffered output enable (OE) controls all ten outputs simultaneously without affecting internal state retention or data loading.
The 74ACT11821DWR uses Texas Instruments' EPIC™ 1-µm CMOS process, enabling TTL-voltage compatibility (VIH = 2 V, VIL = 0.8 V), low input capacitance (4.5 pF), and low-output leakage (±5 µA max in high-Z state). Center-pin VCC/GND placement minimizes switching noise in high-speed bus systems.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Logic Family | ACT (Advanced CMOS TTL-compatible) |
| Function | 10-bit positive-edge-triggered D flip-flop with 3-state outputs |
| Supply Voltage | 4.5 V to 5.5 V - ensures robust operation across industrial rail tolerances |
| Max Clock Frequency | 125 MHz - supports high-speed synchronous bus timing |
| Output Drive | ±24 mA - drives heavy capacitive loads (e.g., >50 pF buses) without external buffers |
| Propagation Delay | tPLH/tPHL ≤ 12.6 ns @ 5 V - enables tight setup/hold timing margins in fast systems |
| Input Compatibility | TTL-level (VIH = 2 V, VIL = 0.8 V) - interoperable with legacy 74LS/TTL logic without level shifters |
Pinout & Package
74ACT11821DWR is packaged in a 28-pin plastic small-outline (SOIC) DW package with wide-body 300-mil spacing and gull-wing leads. The package features center-aligned VCC (pins 27, 28) and GND (pins 6–9) for low-noise power distribution.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1D–10D | Data inputs | Asynchronous D inputs for each of ten flip-flops; TTL-compatible voltage thresholds |
| CLK | Clock input | Positive-edge-triggered global clock; synchronizes all ten Q outputs |
| OE | Output enable | Active-low control: asserts high-impedance state on all Q outputs independently of clock or data |
| 1Q–10Q | Registered outputs | 3-state outputs reflecting D-input state after CLK↑; drive or float per OE state |
| VCC (pins 27, 28) | Power supply | Dual center-placed 5-V supply pins reduce simultaneous switching noise |
| GND (pins 6–9) | Ground | Four adjacent ground pins provide low-inductance return path for high-speed switching |
Key Features
| Feature | Design Value |
|---|---|
| Flow-through architecture | Input-to-output pin mapping (e.g., 1D→1Q, 2D→2Q) enables straight PCB trace routing and reduces crosstalk |
| Center-pin VCC/GND | Minimizes ground bounce and supply noise during simultaneous 10-bit output switching |
| 500 mA latch-up immunity | Guaranteed immunity at 125°C - supports reliable operation in thermally stressed industrial environments |
| Low power dissipation capacitance | 31 pF (outputs disabled), 45 pF (outputs enabled) - reduces dynamic power in high-frequency bus applications |
| TTL-voltage compatible inputs | Accepts standard 74LS logic levels directly - eliminates need for level-shifting circuitry |
Applications
| Memory Address Buffering | Parallel I/O Port Expansion |
|---|---|
Use Scenario: Buffering 10-bit address lines between microcontroller and SRAM or EPROM in embedded systems. IC Role / Device Role / Timing Role: Synchronizes and isolates address signals using positive-edge clock and 3-state control during bus turnaround. Use Value: Enables clean address hold during read/write transitions without bus contention, leveraging OE-controlled high-Z state. |
Use Scenario: Expanding GPIO count on an MCU by adding a 10-bit bidirectional data port with parity support. IC Role / Device Role / Timing Role: Acts as a registered, 3-state I/O latch - data latched on CLK↑, direction controlled via OE and external bus control logic. Use Value: Provides deterministic timing and strong drive (±24 mA) for driving long PCB traces or multiple peripheral inputs. |
| Parity-Enabled Data Bus | Backplane Interface Register |
Use Scenario: Implementing a 10-bit data path with integrated even/odd parity generation in telecom line cards. IC Role / Device Role / Timing Role: Registers data bits and parity bit simultaneously on CLK↑; OE allows shared bus access with parity generator/checker ICs. Use Value: Eliminates need for discrete pull-ups or bus transceivers due to high-drive 3-state outputs and TTL-compatible inputs. |
Use Scenario: Interfacing a local processor to a multi-slot VME or CompactPCI backplane requiring hot-swappable register isolation. IC Role / Device Role / Timing Role: Provides galvanically isolated, clock-synchronized data staging between slot controller and backplane data lines. Use Value: Flow-through pinout and center-power layout minimize signal integrity degradation across 10-bit parallel backplane traces. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar 10-bit bus-interface flip-flop applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 74ACT16374DW | 16-bit version in same DW package; higher pin count (48-pin), identical ACT specs and timing | Requires PCB redesign for wider bus; not drop-in for 10-bit layouts | Select when system requires ≥16-bit data path and board space allows larger footprint |
| SN74ABT16374DGGR | 16-bit ABT family; higher drive (±64 mA), faster tPLH (3.2 ns), but incompatible voltage thresholds (VIH = 2.0 V min only at VCC = 4.5 V) | Not TTL-compatible at lower VCC; unsuitable for mixed 74LS/ACT systems without level adaptation | Prefer for new high-speed designs where ABT's speed and drive outweigh compatibility constraints |
Compared with 74ACT11821DWR, the 74ACT16374DW offers greater data width but demands layout changes, while SN74ABT16374DGGR delivers superior speed and drive at the cost of TTL input compatibility - making 74ACT11821DWR optimal for legacy-compatible, 10-bit industrial bus interfaces.
Availability
74ACT11821DWR is available at Aetrix Electronics and suitable for memory address buffering, parallel I/O port expansion, and parity-enabled data bus applications requiring stable component supply across extended product lifecycles.
Supply support for 74ACT11821DWR 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 innovator founded in 1930, delivering analog, embedded processing, and logic solutions for industrial, automotive, and communications markets.
The 74ACT11821DWR belongs to TI's Advanced CMOS (ACT) logic family, engineered for TTL-compatible operation with enhanced noise immunity and bus-driving capability in industrial control and computing infrastructure.
FAQ
What is the operating temperature range for the 74ACT11821DWR?
The 74ACT11821DWR is characterized for industrial operation from –40°C to +85°C. This rating is explicitly defined in the SCAS156A datasheet and applies to the DW-package variant. Unlike the military-grade 54ACT11821 (–55°C to 125°C), the 74ACT11821DWR is optimized for commercial and industrial environments where extended thermal margin is required without military-spec cost or testing overhead.
Does the 74ACT11821DWR support true bidirectional data flow?
The 74ACT11821DWR does not implement internal bidirectional logic - it is a unidirectional 10-bit D flip-flop with 3-state outputs. However, its OE-controlled high-impedance outputs allow external system-level bidirectional bus operation when paired with complementary devices (e.g., receivers or transceivers) and proper control sequencing. The datasheet confirms OE does not affect internal registers, enabling data retention during bus float.
What is the maximum capacitive load the 74ACT11821DWR can drive reliably?
The 74ACT11821DWR is specified to drive up to 50 pF loads with guaranteed timing (tPLH/tPHL ≤ 12.6 ns at 5 V). Its ±24 mA output current and low output impedance support heavier loads in practice, but timing margins degrade beyond 50 pF unless compensated via reduced clock frequency or series termination - as confirmed by the CL = 50 pF test condition in the switching characteristics table.
Is the 74ACT11821DWR pin-compatible with other 28-pin SOIC bus-interface devices?
No - the 74ACT11821DWR has a unique 28-pin DW pinout optimized for flow-through layout (e.g., 1D→1Q alignment, dual VCC, quad GND). It is not pin-compatible with generic 28-pin SOIC logic devices like octal latches or transceivers. Pin mapping must be verified against the SCAS156A diagram; substitution requires schematic and layout validation.
How does the 74ACT11821DWR handle unused inputs?
Per the SCAS156A datasheet Note 2, unused or floating inputs on the 74ACT11821DWR must be held high or low - typically tied to VCC or GND through resistors or direct connection. Leaving inputs floating risks increased ICC, erratic switching, or ESD susceptibility due to the CMOS input structure. OE and CLK are especially critical to stabilize, as unintended transitions may corrupt register state or output behavior.
74ACT11821DWR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- *
- Package/Case:
- -
- Packaging:
- Bulk
- Product Status:
- Active
- Logic Type:
- -
- Number of Elements:
- -
- Number of Bits per Element:
- -
- Input Type:
- -
- Output Type:
- -
- Current - Output High, Low:
- -
- Voltage - Supply:
- -
- Operating Temperature:
- -
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- -
- Supplier Device Package:
- -
74ACT11821DWR FAQ
1.How can I place an order for 74ACT11821DWR through Aetrix?
Please submit a Request for Quotation (RFQ) for 74ACT11821DWR 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 74ACT11821DWR reliable?
The price and inventory of 74ACT11821DWR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 74ACT11821DWR is usually 5 days.
3.What payment methods are accepted for 74ACT11821DWR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 74ACT11821DWR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 74ACT11821DWR?
74ACT11821DWR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 74ACT11821DWR 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 74ACT11821DWR?
For technical support, including 74ACT11821DWR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 74ACT11821DWR requirements.
6.How does Aetrix verify that 74ACT11821DWR is sourced from the original manufacturer or authorized distributors?
All 74ACT11821DWR 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 74ACT11821DWR meets industry standards.
7.What is the process for return or replacement of 74ACT11821DWR?
All 74ACT11821DWR units undergo pre-shipment inspection (PSI). If there is an issue with 74ACT11821DWR, 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 74ACT11821DWR part is unused and in its original packaging.
Return procedure for 74ACT11821DWR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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