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Texas Instruments SN74ALS29821DW
- Part No.:
- SN74ALS29821DW
- Manufacturer:
- Texas Instruments
- Category:
- Flip Flops
- Package:
- 24-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
SN74ALS29821DW.pdf
- Description:
- IC FF D-TYPE SNGL 10BIT 20SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:4,101
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Product details
Overview
SN74ALS29821DW from Texas Instruments is a 10-bit edge-triggered D-type flip-flop with 3-state outputs, designed for driving highly capacitive or low-impedance bus loads. It operates at 5 V, supports 48 mA sink / −24 mA source output drive, features power-up high-impedance state, and is qualified for 0°C to 70°C industrial operation in SOIC-24 package.
For engineers reviewing the SN74ALS29821DW datasheet, SN74ALS29821DW pinout, SN74ALS29821DW application, or SN74ALS29821DW equivalent, key selection considerations include its 10-bit synchronous latch behavior, OE-controlled 3-state bus interface capability, undershoot-protection circuitry, and compatibility with wider address/data paths requiring parity support.
Technical Context
This device implements ten independent D-type latches triggered on the positive clock edge, each with buffered OE control enabling simultaneous 3-state output management. Its internal logic decouples OE from flip-flop operation-data can be latched or retained while outputs remain high-Z.
Designed for ALS (Advanced Low-Power Schottky) logic family compatibility, it delivers fast propagation delays (2–10 ns CLK→Q), sub-17 ns OE→Q enable/disable times, and robust DC electrical specs including VIH = 2 V, VIL = 0.8 V, VOL = 0.5 V at 48 mA, and ICC = 115 mA max under full load.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Logic Family | ALS (Advanced Low-Power Schottky), compatible with TTL-level inputs and outputs |
| Operating Voltage | 4.75 V to 5.25 V - ensures stable operation across standard 5 V supply tolerances |
| Output Drive | 48 mA sink / −24 mA source - sufficient to drive 50 pF+ buses without external buffers |
| Propagation Delay | 2–10 ns (CLK→Q, CL = 50 pF) - enables reliable timing in high-speed bus interfaces |
| Enable/Disable Time | 1–14 ns (OE→Q, CL = 5 pF) - minimizes bus contention during state transitions |
| Input Thresholds | VIH = 2 V, VIL = 0.8 V - provides noise margin against TTL-compatible signal sources |
| Power-Up State | Outputs default to high-impedance - prevents bus conflicts during system reset or power sequencing |
Pinout & Package
SN74ALS29821DW is housed in a 24-pin SOIC (DW) package with 300-mil width, JEDEC MO-058 compliant, moisture sensitivity level 1, and lead finish NIPDAU.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | OE (Output Enable) | Active-low control input; places all 10 Q outputs in high-impedance state when high |
| 2–11 | 1D–10D | Data inputs synchronized to CLK rising edge; latch values into respective flip-flops |
| 12 | GND | Ground reference for logic and power domains |
| 13 | VCC | Positive supply terminal (4.75–5.25 V); powers internal logic and output drivers |
| 14–23 | 1Q–10Q | 3-state complementary outputs reflecting latched D-input states when OE is low |
| 24 | CLK | Positive-edge-triggered clock input; controls synchronous capture of all 10 D inputs |
Key Features
| Feature | Design Value |
|---|---|
| 10-bit 3-state bus interface | Enables bidirectional data flow on shared address/data buses with parity, eliminating need for external bus transceivers |
| Undershoot-protection circuitry | Prevents negative voltage excursions below GND on outputs during fast switching, improving signal integrity on long traces |
| Buffered OE and CLK inputs | Reduces DC loading on upstream drivers and improves noise immunity compared to unbuffered control signals |
| Power-up high-impedance state | Guarantees no bus contention during power ramp-up or brownout conditions without external reset coordination |
| Functionally equivalent to AM29821 | Supports drop-in replacement in legacy AMD-based designs without layout or firmware changes |
Applications
| Memory Interface Buffering | Industrial I/O Port Expansion |
|---|---|
Use Scenario: Buffering 10-bit address or data lines between microcontroller and SRAM/ROM with parity bit support. IC Role / Device Role / Timing Role: Synchronous latch and bus driver providing controlled timing alignment and isolation between processor and memory subsystem. Use Value: Enables wider memory word access (e.g., 16-bit data + parity) while maintaining clean signal edges and preventing bus contention during read/write cycles. | Use Scenario: Expanding GPIO count on PLC or motion controller using parallel I/O expansion over backplane or ribbon cable. IC Role / Device Role / Timing Role: Bidirectional 10-bit port register with OE-controlled direction and clock-synchronized data capture. Use Value: Delivers 48 mA drive strength per output to directly interface with industrial sensors, relays, and optocouplers without level-shifting or buffering. |
| Legacy Bus Arbitration | Test Equipment Data Capture |
Use Scenario: Managing shared data bus arbitration in MIL-STD-1553 or VMEbus-compatible systems with parity validation. IC Role / Device Role / Timing Role: Edge-triggered register holding bus transaction data until acknowledged, with OE enabling/disabling participation in bus cycles. Use Value: Provides deterministic setup/hold timing (tsu = 4 ns, th = 2 ns) and undershoot protection critical for reliable operation in electrically noisy avionics environments. | Use Scenario: Capturing parallel digital waveform data from ADCs or logic analyzers into test instrumentation memory buffers. IC Role / Device Role / Timing Role: High-speed 10-bit sampling latch synchronized to system clock, feeding captured data to FIFO or DMA controller. Use Value: Achieves 100+ MHz effective sampling rate via 2–10 ns propagation delay and tight timing margins, supporting real-time digital signal acquisition. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar 10-bit 3-state D-type latch applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74ALS29821NT | Same logic function and timing, but in plastic DIP-24 package instead of SOIC-24 | Larger footprint and through-hole mounting; preferred for prototyping or legacy board rework | Select SN74ALS29821NT when manual assembly, socketing, or thermal mass requirements favor DIP packaging |
| AM29821 | Functionally identical per manufacturer documentation; pinout and AC/DC specs match within measurement tolerance | No functional difference in bus interface or timing behavior; direct second-source option | Choose AM29821 only if dual-sourcing is required for supply chain resilience in military-grade programs |
Compared with SN74ALS29821NT and AM29821, the SN74ALS29821DW offers surface-mount compatibility, tighter thermal resistance, and automated assembly readiness while retaining identical logic behavior, timing, and drive capability-making it optimal for volume production of industrial control and test equipment.
Availability
SN74ALS29821DW is available at Aetrix Electronics and suitable for industrial I/O expansion, memory interface buffering, legacy bus arbitration, and test equipment data capture requiring stable component supply and long-term lifecycle support.
Supply support for SN74ALS29821DW 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 ICs for industrial, automotive, and communications markets.
The SN74ALS29821DW belongs to TI's legacy ALS logic family, engineered specifically for high-drive, low-noise bus interfacing in systems requiring parity-aware data path expansion and deterministic timing control.
FAQ
What is the operating temperature range for SN74ALS29821DW?
The SN74ALS29821DW is characterized for operation from 0°C to 70°C, meeting industrial-grade environmental requirements. This range is distinct from the military-grade SN54ALS29821 variant, which supports −55°C to 125°C. The SN74ALS29821DW's specifications-including propagation delay, output drive, and input thresholds-are guaranteed across this full industrial temperature span.
Does SN74ALS29821DW support hot insertion or live bus connection?
Yes, the SN74ALS29821DW supports safe live connection due to its power-up high-impedance state and undershoot-protection circuitry on all outputs. When powered, outputs remain in high-Z until OE is asserted low, preventing bus conflicts. The device also tolerates −1.2 V input clamping (VIK) and 5.5 V absolute max input voltage, enhancing robustness during hot-swap events in backplane or modular systems.
Can SN74ALS29821DW drive a 300-pF bus load reliably?
Yes, the SN74ALS29821DW is explicitly rated for CL = 300 pF operation, with tPLH/tPHL ≤ 21 ns and tPZL/tPZH ≤ 29.5 ns under those conditions. Its 48 mA sink current ensures fast edge rates and minimal droop, making it suitable for driving long PCB traces, multiple TTL inputs, or terminated transmission lines common in industrial backplanes and instrumentation interfaces.
Is SN74ALS29821DW pin-compatible with other 10-bit latch devices like SN74ALS16373?
No, SN74ALS29821DW is not pin-compatible with SN74ALS16373. While both are 10-bit latches, SN74ALS16373 uses a different pinout (including separate LE and OE controls), lacks undershoot protection, and has distinct timing parameters. The SN74ALS29821DW's unique 24-pin SOIC layout-with CLK on pin 24, OE on pin 1, and sequential D/Q mapping-is specific to the ALS29821 family and validated only against AM29821 and SN74ALS29821NT.
What is the maximum recommended clock frequency for SN74ALS29821DW?
The SN74ALS29821DW does not specify a maximum clock frequency in its datasheet; instead, timing is defined by minimum pulse width (tw ≥ 7 ns) and setup/hold requirements (tsu = 4 ns, th = 2 ns). Based on these, the practical maximum clock rate is ~70 MHz for reliable operation with margin. For higher-frequency applications, designers must verify timing closure using worst-case propagation (10 ns) and skew budgets in their specific PCB layout.
SN74ALS29821DW Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74ALS
- Package/Case:
- 24-SOIC (0.295", 7.50mm Width)
- Packaging:
- Bulk
- Product Status:
- Active
- Function:
- Standard
- Type:
- D-Type
- Output Type:
- Tri-State, Non-Inverted
- Number of Elements:
- 1
- Number of Bits per Element:
- 10
- Clock Frequency:
- -
- Max Propagation Delay @ V, Max CL:
- 16ns @ 5V, 300pF
- Trigger Type:
- Positive Edge
- Current - Output High, Low:
- 24mA, 48mA
- Voltage - Supply:
- 4.75V ~ 5.25V
- Current - Quiescent (Iq):
- 115 mA
- Input Capacitance:
- -
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 24-SOIC
SN74ALS29821DW FAQ
1.How can I place an order for SN74ALS29821DW through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74ALS29821DW 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 SN74ALS29821DW reliable?
The price and inventory of SN74ALS29821DW are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74ALS29821DW is usually 5 days.
3.What payment methods are accepted for SN74ALS29821DW?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74ALS29821DW transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74ALS29821DW?
SN74ALS29821DW orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74ALS29821DW 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 SN74ALS29821DW?
For technical support, including SN74ALS29821DW datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74ALS29821DW requirements.
6.How does Aetrix verify that SN74ALS29821DW is sourced from the original manufacturer or authorized distributors?
All SN74ALS29821DW 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 SN74ALS29821DW meets industry standards.
7.What is the process for return or replacement of SN74ALS29821DW?
All SN74ALS29821DW units undergo pre-shipment inspection (PSI). If there is an issue with SN74ALS29821DW, 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 SN74ALS29821DW part is unused and in its original packaging.
Return procedure for SN74ALS29821DW:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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