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Texas Instruments SN74BCT29821NT
- Part No.:
- SN74BCT29821NT
- Manufacturer:
- Texas Instruments
- Category:
- Flip Flops
- Package:
- 24-DIP (0.300", 7.62mm)
- Datasheet:
-
SN74BCT29821NT.pdf
- Description:
- IC FF D-TYPE SNGL 10BIT 24DIP
- Quantity:
- Payment:
- Shipping:
Inventory:3,605
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Product details
Overview
SN74BCT29821NT from Texas Instruments is a 10-bit edge-triggered D-type bus-interface flip-flop with 3-state outputs, designed for driving high-capacitance or low-impedance bus lines. It operates at 5 V (4.5–5.5 V), supports 125 MHz clock frequency, delivers ±48 mA output drive, and features independent output-enable control with 2 ns enable/disable propagation delay.
For engineers reviewing the SN74BCT29821NT datasheet, SN74BCT29821NT pinout, SN74BCT29821NT application, or SN74BCT29821NT equivalent, key selection considerations include its BiCMOS-based low ICCZ standby current (2–6 mA), TTL-compatible input thresholds, bus-hold-free 3-state behavior, and NT-package compatibility with legacy through-hole PCB layouts.
Technical Context
This device implements ten synchronous D-type flip-flops with positive-edge clock triggering and independent 3-state output control via an active-low OE input. Internal logic retains stored data regardless of OE state, enabling concurrent data latching and bus isolation.
Its BiCMOS architecture combines bipolar input stages for TTL-level compatibility and CMOS output drivers for high-current sinking (48 mA) and sourcing (−24 mA), while maintaining low quiescent supply current (ICCZ ≤ 6 mA) and fast switching (tPLH/tPHL ≤ 10 ns at CL = 50 pF).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage | 4.5 V to 5.5 V - Ensures robust operation across industrial-grade 5 V rails with margin for ripple and drop. |
| Max Clock Frequency | 125 MHz - Supports high-speed synchronous bus interfacing without setup/hold violations. |
| Output Drive | 48 mA sink / −24 mA source - Directly drives terminated transmission lines or multiple TTL loads without external buffers. |
| 3-State Enable Delay | tPZH/tPLZ ≤ 7 ns - Enables precise timing control when multiplexing shared buses in real-time systems. |
| Input Capacitance | 5.5 pF - Minimizes loading on upstream drivers and preserves signal integrity in dense routing. |
| Standby ICCZ | 2–6 mA - Reduces system-level power in idle bus states compared to standard bipolar bus transceivers. |
| Operating Temperature | 0°C to 70°C - Qualified for commercial and industrial ambient environments without derating. |
Pinout & Package
SN74BCT29821NT uses a 24-pin plastic dual-inline package (PDIP, NT suffix), 300-mil width, with through-hole mounting and standard DIP pin spacing (0.1″). Pin 1 is top-left corner, pin 12 is top-right, pin 13 is bottom-right, pin 24 is bottom-left.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | OE (Active-Low Output Enable) | Global 3-state control: logic low enables Q outputs; high places all Qs in high-impedance mode. |
| 2–11 | 1D–10D | Data inputs synchronized to CLK↑; each directly maps to corresponding Q output. |
| 12 | GND | Power ground reference for all internal logic and output drivers. |
| 13 | VCC | +5 V supply rail; decoupling required within 1 inch of this pin for stable switching. |
| 14–23 | 1Q–10Q | True (non-inverted) registered outputs; each independently 3-state capable under OE control. |
| 24 | CLK | Single global clock input; positive-edge triggered; must meet 7 ns minimum pulse width. |
Key Features
| Feature | Design Value |
|---|---|
| BiCMOS Process Technology | Combines TTL-compatible input thresholds (VIH = 2 V, VIL = 0.8 V) with CMOS output efficiency and low ICCZ. |
| Independent OE Control | Allows data retention and new data capture during 3-state bus isolation-no impact on internal flip-flop state. |
| High-Current Bus Driving | 48 mA sink capability eliminates need for external line drivers in backplane or motherboard trace applications. |
| Low Propagation Skew | Matched tPLH/tPHL (≤10 ns) ensures deterministic timing across all 10 channels for parallel data paths. |
| ESD Robustness | Exceeds 2000 V HBM and 200 V machine model-reduces handling sensitivity in manual assembly and test. |
Applications
| Backplane Data Latching | Industrial I/O Port Expansion |
|---|---|
Use Scenario: Latching parallel status data from sensor modules onto a shared 10-bit backplane bus in programmable logic controllers. IC Role / Device Role / Timing Role: Synchronous 10-bit register buffering with simultaneous edge-triggered capture and 3-state bus release. Use Value: Eliminates external bus transceivers and reduces board space by integrating clocked storage + bus drive + isolation in one NT-package IC. |
Use Scenario: Expanding microcontroller GPIO count to drive discrete actuators (relays, solenoids) via a buffered parallel interface. IC Role / Device Role / Timing Role: Level-shifting and current-boosting interface between low-drive MCU pins and high-current industrial loads. Use Value: Provides 48 mA per output-sufficient to directly drive relay coils or LED arrays without discrete driver transistors. |
| Legacy System Bus Interface | Test Equipment Signal Conditioning |
Use Scenario: Interfacing modern FPGA-based controllers to legacy 5 V TTL bus architectures requiring strict voltage and timing compliance. IC Role / Device Role / Timing Role: Voltage- and timing-transparent bridge ensuring setup/hold timing margins (tsu = 7 ns, th = 1 ns) are met. Use Value: Maintains full 125 MHz bandwidth while preserving legacy PDIP footprint compatibility-no PCB redesign needed. |
Use Scenario: Conditioning parallel digital stimulus signals in automated test equipment before routing to DUT interface connectors. IC Role / Device Role / Timing Role: Glitch-free signal registration and controlled bus release during test vector transitions. Use Value: Low skew (<10 ns) and fast 3-state disable (tPLZ ≤ 12 ns) prevent metastability and bus contention during pattern switching. |
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 |
|---|---|---|---|
| SN74ACT29821N | AC-family CMOS; lower ICCZ (1 µA), but only ±24 mA drive; no BiCMOS speed advantage. | Lower power, lower drive - suitable for low-noise, low-current systems where 125 MHz is not required. | Select when minimizing static power dominates over bus drive strength and maximum frequency. |
| SN74LS29821N | Standard TTL; higher ICC (60 mA), slower (30 MHz max), no 3-state ICCZ optimization. | Compatible with legacy LS-TTL designs but lacks BiCMOS efficiency and speed. | Choose only for direct replacement in existing LS-based boards where no performance upgrade is needed. |
Compared with SN74ACT29821N and SN74LS29821N, the SN74BCT29821NT uniquely balances 125 MHz operation, 48 mA drive, and sub-6 mA ICCZ-making it optimal for high-speed industrial bus interfaces where both timing headroom and load-driving capability are critical.
Availability
SN74BCT29821NT is available at Aetrix Electronics and suitable for industrial I/O expansion, legacy system upgrades, and high-speed backplane latching requiring stable component supply and long-term PDIP package continuity.
Supply support for SN74BCT29821NT 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.
The SN74BCT29821NT belongs to TI's BCT (Bipolar-CMOS Transistor) logic family, engineered to deliver TTL-compatible interface performance with CMOS-like power efficiency for demanding bus-interface applications.
FAQ
What is the operating temperature range for the SN74BCT29821NT?
The SN74BCT29821NT is characterized for operation from 0°C to 70°C. This commercial-industrial temperature grade ensures reliable performance in non-extended-environment applications such as factory automation controllers, test equipment, and office electronics. The device does not support extended (−40°C to 85°C) or automotive temperature ranges.
Does the SN74BCT29821NT support hot insertion or live bus swapping?
The SN74BCT29821NT is not rated for hot insertion. Its absolute maximum ratings specify that output voltage in the disabled or power-off state must remain within −0.5 V to 5.5 V, and no bus-fault protection (e.g., current limiting during partial power-up) is documented. For hot-swap applications, external protection circuitry or purpose-built hot-swap ICs are required alongside the SN74BCT29821NT.
Can the SN74BCT29821NT be used with 3.3 V logic systems?
No-the SN74BCT29821NT requires a 4.5 V to 5.5 V supply and is not 3.3 V tolerant. Its input thresholds (VIH = 2 V, VIL = 0.8 V) are TTL-compatible but assume a 5 V rail; connecting 3.3 V signals directly risks violating VIH min and may cause unreliable operation. Level translation is required when interfacing with 3.3 V systems.
How does the OE pin affect internal flip-flop operation in the SN74BCT29821NT?
The OE pin has no effect on internal flip-flop operation in the SN74BCT29821NT. Data can be latched on CLK↑ and retained indefinitely regardless of OE state. When OE is high, outputs go high-impedance-but stored Q values remain unchanged and new D inputs continue to be sampled on subsequent clocks. This enables seamless bus arbitration and background data loading.
Is the SN74BCT29821NT RoHS compliant?
Yes-the SN74BCT29821NT (orderable part SN74BCT29821NTE4) is RoHS-compliant and Pb-Free per TI's eco plan. It meets EU RoHS Directive 2011/65/EU requirements, with lead content below 0.1% by weight in homogeneous materials. Full compliance documentation is available in TI's official product change notices and packaging addenda.
SN74BCT29821NT Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74BCT
- Package/Case:
- 24-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:
- 10
- Clock Frequency:
- 125 MHz
- Max Propagation Delay @ V, Max CL:
- 10ns @ 5V, 50pF
- Trigger Type:
- Positive Edge
- Current - Output High, Low:
- 24mA, 48mA
- Voltage - Supply:
- 4.5V ~ 5.5V
- Current - Quiescent (Iq):
- 10 mA
- Input Capacitance:
- 5.5 pF
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 24-PDIP
SN74BCT29821NT FAQ
1.How can I place an order for SN74BCT29821NT through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74BCT29821NT 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 SN74BCT29821NT reliable?
The price and inventory of SN74BCT29821NT are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74BCT29821NT is usually 5 days.
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SN74BCT29821NT orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74BCT29821NT 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 SN74BCT29821NT?
For technical support, including SN74BCT29821NT datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74BCT29821NT requirements.
6.How does Aetrix verify that SN74BCT29821NT is sourced from the original manufacturer or authorized distributors?
All SN74BCT29821NT 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 SN74BCT29821NT meets industry standards.
7.What is the process for return or replacement of SN74BCT29821NT?
All SN74BCT29821NT units undergo pre-shipment inspection (PSI). If there is an issue with SN74BCT29821NT, 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 SN74BCT29821NT part is unused and in its original packaging.
Return procedure for SN74BCT29821NT:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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