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Texas Instruments SN74ACT2229DWR
- Part No.:
- SN74ACT2229DWR
- Manufacturer:
- Texas Instruments
- Category:
- FIFOs Memory
- Package:
- 28-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
SN74ACT2229DWR.pdf
- Description:
- IC FIFO SYNC 256X1X2 9NS 28SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:1,697
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Product details
Overview
SN74ACT2229DWR from Texas Instruments is a dual asynchronous FIFO memory IC with two independent 256 × 1-bit serial-data buffers, supporting up to 60 MHz clock frequency, 9 ns access time, and 3-state outputs. It operates across –40°C to 85°C and is used in telecom elastic stores for OC-1 rate synchronization and time-division multiplexing.
For engineers reviewing the SN74ACT2229DWR datasheet, SN74ACT2229DWR pinout, SN74ACT2229DWR application, or SN74ACT2229DWR equivalent, key selection criteria include dual 256-word depth, asynchronous read/write clocks, synchronized IR/OR flags, half-full/almost-full status signaling, and SOIC-28 packaging with industrial temperature range.
Technical Context
The SN74ACT2229DWR implements two independent 256 × 1-bit FIFOs using dual-port SRAM architecture, each with fully synchronous read and write control logic. Each FIFO features separate free-running clocks (1WRTCLK/2WRTCLK and 1RDCLK/2RDCLK), with input-ready (1IR/2IR) flags synchronized to write clocks via two flip-flop stages and output-ready (1OR/2OR) flags synchronized to read clocks via three flip-flop stages.
Status generation includes half-full (1HF/2HF) asserted at ≥128 bits stored, and almost-full/almost-empty (1AF/AE/2AF/AE) asserted when ≤8 bits remain or ≤8 locations are empty. Reset requires four low-to-high transitions on both RDCLK and WRTCLK while RESET is low, initializing flags to defined states without requiring external timing coordination.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| FIFO Depth | 2 × 256 words × 1 bit - supports longer data buffering than 64-word variants for jitter absorption in high-rate serial links. |
| Max Clock Frequency | 60 MHz - enables use in OC-1 (51.84 Mbps) telecom applications with sufficient timing margin. |
| Access Time | 9 ns - defines minimum clock period for reliable read/write cycles under worst-case conditions. |
| Supply Voltage | 4.5 V to 5.5 V - compatible with standard 5-V TTL/CMOS systems and tolerant of rail variation. |
| Operating Temperature | –40°C to +85°C - qualified for industrial and telecom infrastructure environments. |
| Output Drive | 16 mA sink / –8 mA source - ensures robust signal integrity driving 50-pF loads at high speed. |
| Input Clamp Current | ±20 mA - specifies absolute maximum transient current handling without damage during overvoltage events. |
Pinout & Package
Packaged in a 28-pin SOIC (DW) body with 1.27 mm pitch, 12.7 mm width, and tube packaging (20 units per tube). Pin assignments are validated per TI SCAS220C datasheet Figure 1 (top view).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 15 | 1HF / 2HF | Half-full flag outputs - indicate ≥128 bits stored per FIFO; used for flow control in multiplexers. |
| 2, 16 | 1AF/AE / 2AF/AE | Almost-full/almost-empty flags - assert when ≤8 bits remain or ≤8 empty slots exist; enable early buffer management. |
| 3, 17 | 1WRTCLK / 2WRTCLK | Write clock inputs - low-to-high transitions trigger writes when WRTEN and IR are high; asynchronous to RDCLK. |
| 4, 18 | 1WRTEN / 2WRTEN | Write enable inputs - must be high with IR to allow data entry; prevents overflow during full condition. |
| 5, 19 | 1IR / 2IR | Input-ready flags - synchronized to respective WRTCLK; low = FIFO full, disables further writes. |
| 6, 20 | 1D / 2D | Data inputs - serial bit stream enters FIFO on active WRTCLK edge when WRTEN and IR are high. |
| 7, 8 | GND | Ground terminals - dual ground pins reduce noise coupling between FIFO sections and improve signal integrity. |
| 9, 23 | 1RESET / 2RESET | Reset inputs - shared reset logic requires four WRTCLK and four RDCLK edges low to initialize all flags and pointers. |
| 10, 24 | 1Q / 2Q | Data outputs - 3-state, driven only when OE is high; first valid read occurs on third RDCLK edge after first write. |
| 11, 25 | 1OR / 2OR | Output-ready flags - synchronized to respective RDCLK; low = FIFO empty, disables reads until data available. |
| 12, 26 | 1RDEN / 2RDEN | Read enable inputs - must be high with OR to allow data output on active RDCLK edge. |
| 13, 27 | 1RDCLK / 2RDCLK | Read clock inputs - low-to-high transitions sample Q outputs when RDEN and OR are high; asynchronous to WRTCLK. |
| 14, 28 | 1OE / 2OE | Output enable inputs - low places Q outputs in high-impedance state; allows bus sharing without external isolation. |
| 21, 22 | VCC | Power supply - dual VCC pins minimize IR drop and stabilize internal logic during simultaneous read/write activity. |
Key Features
| Feature | Design Value |
|---|---|
| Dual independent 256 × 1 FIFOs | Enables concurrent buffering of two serial streams without cross-talk, ideal for TDM aggregation. |
| Asynchronous read/write clocks | Eliminates need for clock domain synchronization logic, reducing design complexity in multi-source systems. |
| Synchronized IR/OR flags | Two-stage (IR) and three-stage (OR) metastability hardening ensures reliable handshaking across clock domains. |
| Half-full and almost-full/empty flags | Provides granular buffer occupancy feedback for adaptive flow control and pulse-stuffing regulation. |
| 3-state outputs with independent OE | Allows direct connection to shared data buses without external transceivers or pull-up networks. |
Applications
| Telecom Elastic Store | Time-Division Multiplexer |
|---|---|
Use Scenario: Absorbing clock jitter between OC-1 line interfaces operating at nominally identical but phase-independent rates. IC Role / Device Role / Timing Role: Dual 256-bit FIFO acts as elastic buffer per channel, decoupling transmit/receive clock domains while maintaining data order. Use Value: Enables deterministic latency alignment and eliminates bit slips caused by Plesiochronous clock drift. | Use Scenario: Concentrating two independent serial data streams into one composite output using a time-division scheme. IC Role / Device Role / Timing Role: Each FIFO buffers one input stream; HF/AF-AE flags drive multiplexer select logic to balance read timing. Use Value: Reduces transmission delay versus half-full-only control by triggering reads earlier in buffer fill cycle. |
| Industrial Serial Bridge | Protocol Translation Interface |
Use Scenario: Bridging UART-based sensor data (low-speed, variable rate) to a fixed-rate SPI master controller. IC Role / Device Role / Timing Role: SN74ACT2229DWR absorbs bursty UART traffic and presents steady output to SPI interface via controlled RDCLK. Use Value: Prevents UART overrun and SPI underflow by isolating timing mismatches with hardware-managed buffering. | Use Scenario: Interfacing legacy 1-bit serial peripherals (e.g., opto-isolated status lines) to modern microcontrollers with parallel GPIO. IC Role / Device Role / Timing Role: Serial-to-parallel conversion via FIFO depth accumulation; OR flag triggers MCU interrupt for batch read. Use Value: Offloads bit-serial polling from firmware, enabling deterministic response to asynchronous external events. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar FIFO memory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74ACT2227DWR | 64 × 1 depth per FIFO (¼ capacity); identical pinout, timing, and flag structure. | Better suited for lower-latency, shorter-burst buffering where 256-word depth is unnecessary. | Select when system jitter tolerance is lower and board space or cost optimization favors reduced memory size. |
| 7200L25SOI | 256 × 9-bit FIFO; wider word width, different pinout, no AF/AE flag; 5-V tolerant CMOS. | Designed for parallel data paths (e.g., microprocessor bus interfacing), not serial bit-stream buffering. | Choose only if application requires multi-bit word storage and can accommodate non-1-bit architecture and layout changes. |
Compared with SN74ACT2227DWR, the SN74ACT2229DWR provides quadruple buffer depth for extended jitter absorption, while 7200L25SOI trades serial simplicity for parallel throughput-neither is pin-compatible, and both require distinct PCB layout and firmware adaptation.
Availability
SN74ACT2229DWR is available at Aetrix Electronics and suitable for telecom infrastructure, industrial serial bridging, protocol translation interfaces, and time-division multiplexing requiring stable component supply and long-lifecycle support.
Supply support for SN74ACT2229DWR 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 specializing in analog, embedded processing, and logic solutions, with decades of heritage in high-reliability interface and memory products.
The SN74ACT2229DWR belongs to TI's advanced CMOS FIFO family designed specifically for serial-data buffering in plesiochronous systems, targeting telecom, industrial automation, and digital communications equipment.
FAQ
What is the FIFO depth configuration of the SN74ACT2229DWR?
The SN74ACT2229DWR contains two independent FIFOs, each configured as 256 words × 1 bit. This differs from the SN74ACT2227DWR (64 × 1) and is explicitly confirmed in TI's SCAS220C datasheet revision October 1997. The 256-word depth enables longer jitter absorption windows in OC-1 and similar high-speed serial applications. Each FIFO operates autonomously with dedicated clocks and status flags.
Does the SN74ACT2229DWR support asynchronous read and write clock domains?
Yes, the SN74ACT2229DWR fully supports asynchronous operation: the 1WRTCLK/2WRTCLK and 1RDCLK/2RDCLK pairs may run at different frequencies and phases with no synchronization requirement. Input-ready (IR) and output-ready (OR) flags are internally synchronized using two- and three-stage flip-flop chains respectively, ensuring metastability-hardened handshaking across clock boundaries without external logic.
What are the voltage and temperature specifications for the SN74ACT2229DWR?
The SN74ACT2229DWR operates from 4.5 V to 5.5 V supply voltage and is characterized for –40°C to +85°C ambient temperature. These values are specified in the "Recommended Operating Conditions" table of the SCAS220C datasheet. Absolute maximum ratings extend to –0.5 V to 7 V on VCC and –65°C to +150°C storage, but functional operation is guaranteed only within the recommended ranges.
How does the reset sequence work on the SN74ACT2229DWR?
The SN74ACT2229DWR requires a specific hardware reset: four low-to-high transitions on both 1RDCLK/2RDCLK and 1WRTCLK/2WRTCLK while 1RESET/2RESET is held low. This initializes all status flags (IR, OR, HF low; AF/AE high) and clears internal pointers. The sequence is mandatory after power-up and is detailed in Figure 1 of the SCAS220C datasheet - no software or single-pulse reset is supported.
What package type and marking does the SN74ACT2229DWR use?
The SN74ACT2229DWR is supplied in a 28-pin SOIC (DW) package with 1.27 mm lead pitch, marked "ACT2229" on the top surface. Per TI's Packaging Information Addendum, it ships in tubes of 20 units, has NIPDAU lead finish, and carries MSL Level-1 rating (unlimited floor life at ≤30°C/60% RH). The DW package is distinct from narrower or smaller-body variants and is verified in TI's official ordering documentation.
SN74ACT2229DWR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74ACT
- Package/Case:
- 28-SOIC (0.295", 7.50mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Programmable:
- Not Verified
- Memory Size:
- 512 (256 x 1 x 2)
- Function:
- Synchronous
- Data Rate:
- 60MHz
- Access Time:
- 9ns
- Voltage - Supply:
- 4.5 V ~ 5.5 V
- Current - Supply (Max):
- 400µA
- Bus Directional:
- Uni-Directional
- Expansion Type:
- -
- Programmable Flags Support:
- No
- Retransmit Capability:
- No
- FWFT Support:
- No
- Operating Temperature:
- -40°C ~ 85°C
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 28-SOIC
SN74ACT2229DWR FAQ
1.How can I place an order for SN74ACT2229DWR through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74ACT2229DWR 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 SN74ACT2229DWR reliable?
The price and inventory of SN74ACT2229DWR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74ACT2229DWR is usually 5 days.
3.What payment methods are accepted for SN74ACT2229DWR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74ACT2229DWR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74ACT2229DWR?
SN74ACT2229DWR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74ACT2229DWR 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 SN74ACT2229DWR?
For technical support, including SN74ACT2229DWR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74ACT2229DWR requirements.
6.How does Aetrix verify that SN74ACT2229DWR is sourced from the original manufacturer or authorized distributors?
All SN74ACT2229DWR 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 SN74ACT2229DWR meets industry standards.
7.What is the process for return or replacement of SN74ACT2229DWR?
All SN74ACT2229DWR units undergo pre-shipment inspection (PSI). If there is an issue with SN74ACT2229DWR, 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 SN74ACT2229DWR part is unused and in its original packaging.
Return procedure for SN74ACT2229DWR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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