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Texas Instruments SN74ACT7806-20DL
- Part No.:
- SN74ACT7806-20DL
- Manufacturer:
- Texas Instruments
- Category:
- FIFOs Memory
- Package:
- 56-BSSOP (0.295", 7.50mm Width)
- Datasheet:
-
SN74ACT7806-20DL.pdf
- Description:
- IC FIFO ASYNC 256X18 56SSOP
- Quantity:
- Payment:
- Shipping:
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Product details
Overview
SN74ACT7806-20DL from Texas Instruments is a 256 × 18-bit strobed FIFO memory IC designed for high-speed data buffering between asynchronous clock domains. It delivers 15 ns access time, supports 50 MHz data rates, features programmable almost-full/almost-empty flags, and operates across 0°C to 70°C. It is used in telecom line cards, video frame synchronizers, and protocol bridging interfaces where deterministic latency and depth-aware flow control are required.
For engineers reviewing the SN74ACT7806-20DL datasheet, SN74ACT7806-20DL pinout, SN74ACT7806-20DL application, or SN74ACT7806-20DL equivalent, key selection criteria include its 56-pin SSOP (DL) package, dual-clock (LDCK/UNCK) strobed architecture, 3-state outputs with OE control, and programmable AF/AE flag offsets - all critical for synchronous-to-asynchronous interface design and buffer depth management.
Technical Context
The SN74ACT7806-20DL implements a 256-word × 18-bit static RAM core with independent load and unload pointers controlled by separate rising-edge-triggered clocks (LDCK and UNCK). Its status logic generates FULL, EMPTY, HF, and programmable AF/AE flags based on real-time word count, enabling precise buffer occupancy monitoring without external logic.
Flag programming occurs post-reset via D0–D6 latching on LDCK edges when PEN is low, supporting configurable X (almost-empty) and Y (almost-full) thresholds up to 127 words. The device uses low-power advanced CMOS technology, guarantees 50-MHz operation at VCC = 4.5–5.5 V, and maintains TTL-compatible input thresholds with 3-state outputs driven by OE.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Depth × Width | 256 × 18 bits - provides 4,608-bit buffer capacity for parallel data streams with fine-grained occupancy control. |
| Access Time | 15 ns (max) - enables sub-20-ns read/write turnaround for tight-timing interfaces like video pixel pipelines. |
| Max Clock Frequency | 50 MHz - supports sustained 900 MB/s aggregate throughput (18 bits × 50 MHz) in burst-mode operation. |
| Supply Voltage | 4.5 V to 5.5 V - compatible with standard 5-V TTL/CMOS systems and tolerant of rail variation in industrial backplanes. |
| Operating Temperature | 0°C to 70°C - rated for commercial-grade embedded systems including networking equipment and test instrumentation. |
| Output Drive | IOH = –8 mA / IOL = 16 mA - sufficient fanout for driving multiple 74ACT loads or trace-matched PCB lines without buffers. |
| Power Dissipation | ICC = 400 µA (typ) - ultra-low static current enables use in power-constrained modules without thermal derating. |
Pinout & Package
Packaged in a 56-pin Shrink Small-Outline Package (SSOP-DL), 300-mil body width, 25-mil center-to-center lead pitch, RoHS-compliant NIPDAU finish, MSL Level-1.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (RESET) | Asynchronous reset input | Drives FULL high, EMPTY/HF low; required at power-up to initialize pointer state and flag logic. |
| 2–9, 11–12, 14–17 (D0–D17) | 18-bit parallel data input | Writes data on LDCK↑; D0–D6 also carry AF/AE offset values during PEN-enabled programming mode. |
| 22 (HF) | Half-full status flag output | Asserts high when ≥128 words stored - used for mid-buffer throttling or DMA trigger points. |
| 23 (PEN) | Program enable input | Enables AF/AE offset latching on first two LDCK↑ edges after RESET; must be held high for default X=Y=32. |
| 24 (AF/AE) | Programmable status flag output | High when FIFO contains ≤X or ≥(256−Y) words - configures early warning for underflow/overflow conditions. |
| 25 (LDCK) | Load clock input | Rising edge writes one word; disabled when FULL is low - prevents overwriting full buffer. |
| 28 (FULL) | Full status flag output | Active-low signal indicating no further writes accepted - essential for handshake-based write arbitration. |
| 29 (EMPTY) | Empty status flag output | Active-low signal indicating no valid reads available - prevents stale data reads in consumer logic. |
| 32 (UNCK) | Unload clock input | Rising edge reads one word; disabled when EMPTY is low - ensures read validity and prevents underflow. |
| 33–34, 36–38, 40–43, 45–49, 51, 53–55 (Q0–Q17) | 18-bit parallel data output | Non-inverting, 3-state outputs enabled by OE low; reflect data loaded on prior LDCK↑ cycles. |
| 56 (OE) | Output enable input | Active-low control for Q0–Q17 bus isolation - allows shared data bus usage without contention. |
Key Features
| Feature | Design Value |
|---|---|
| Strobed dual-clock architecture | Independent LDCK and UNCK inputs allow fully asynchronous read/write domains - eliminates need for clock domain crossing logic. |
| Programmable AF/AE flag | Configurable almost-full/almost-empty thresholds (X/Y up to 127) enable adaptive flow control tailored to system-level latency and burst depth requirements. |
| Full/Empty/Half-full status flags | Dedicated open-drain-compatible outputs provide immediate visibility into buffer occupancy - reduces software polling overhead in microcontroller-based hosts. |
| Pin-to-pin compatibility | Direct replacement for SN74ACT7804 (128×18) and SN74ACT7814 (512×18) - simplifies design reuse and scalability across buffer depth variants. |
| Low-power advanced CMOS | 400 µA typical ICC at 5 V enables integration into power-sensitive modules without heatsinking or voltage regulation penalties. |
Applications
| Telecom Line Card Buffering | Video Frame Synchronization |
|---|---|
|
Use Scenario: Absorbing jitter and phase misalignment between TDM framer and packet-switched backplane clocks in DSLAM or ONU hardware. IC Role / Device Role / Timing Role: Strobed FIFO providing deterministic latency compensation and elastic store functionality between 8 kHz and 125 MHz domains. Use Value: Enables glitch-free payload transfer using FULL/EMPTY handshaking while maintaining 256-word depth margin for worst-case slip events. |
Use Scenario: Aligning progressive-scan video frames between HDMI receiver and display controller operating at different pixel clocks. IC Role / Device Role / Timing Role: Parallel 18-bit FIFO acting as a frame-rate converter buffer with HF-triggered DMA initiation and AF/AE-driven underflow prevention. Use Value: Eliminates visible tearing by guaranteeing continuous pixel stream delivery, leveraging 15 ns access time for sub-line latency. |
| Protocol Bridging Interface | Industrial Data Acquisition Buffer |
|
Use Scenario: Interfacing SPI-configured sensor hub with parallel-bus MCU in factory automation gateway. IC Role / Device Role / Timing Role: Depth-managed FIFO decoupling bursty serial input from deterministic parallel readout, synchronized via LDCK/UNCK. Use Value: Prevents data loss during MCU interrupt latency spikes using programmable AF flag to initiate pre-emptive fetch before buffer depletion. |
Use Scenario: Aggregating analog channel samples from multi-channel ADCs into a unified stream for Ethernet transmission. IC Role / Device Role / Timing Role: High-reliability 18-bit-wide FIFO absorbing sample bursts at 50 MHz while feeding slower MAC-layer logic via UNCK. Use Value: Ensures zero-sample loss across temperature range (0°C–70°C) with FULL/EMPTY flags enabling robust firmware flow control. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar FIFO memory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74ACT7804-20DL | 128 × 18-bit depth (half capacity), identical pinout, timing, and flag set. | Suitable for lower-depth buffering where 128-word margin suffices; not usable when >128-word latency absorption is required. | Select when system-level jitter budget permits reduced buffer depth and board space is constrained. |
| SN74ACT7814-20DL | 512 × 18-bit depth (double capacity), identical pinout, timing, and flag set. | Required for applications needing >256-word elasticity, such as long-haul packet buffering or multi-frame video stores. | Choose when future-proofing for higher data rates or extended synchronization windows is mandatory. |
Compared with SN74ACT7804-20DL and SN74ACT7814-20DL, the SN74ACT7806-20DL offers optimal balance of depth, speed, and footprint for mid-range buffering - avoiding over-provisioning cost while exceeding 128-word limitations of legacy designs.
Availability
SN74ACT7806-20DL is available at Aetrix Electronics and suitable for telecom infrastructure, video processing, industrial data acquisition, and protocol bridging applications requiring stable component supply and long-term obsolescence management.
Supply support for SN74ACT7806-20DL 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 ICs.
The SN74ACT7806-20DL belongs to TI's Widebus™ family of high-speed FIFOs, engineered specifically for deterministic data buffering in mixed-clock-domain systems where latency predictability and flag-driven flow control are critical.
FAQ
What is the maximum data rate supported by the SN74ACT7806-20DL?
The SN74ACT7806-20DL supports a maximum clock frequency of 50 MHz on both LDCK and UNCK inputs, enabling sustained data throughput of 900 MB/s (18 bits × 50 MHz). This rating is guaranteed under recommended operating conditions (VCC = 4.5–5.5 V, TA = 0°C to 70°C) with CL = 50 pF loads, as verified in the SCAS438C datasheet timing tables.
How does the AF/AE flag programming work on the SN74ACT7806-20DL?
After RESET assertion, the SN74ACT7806-20DL enters programming mode when PEN is pulled low before the first LDCK↑. On that rising edge, D0–D6 latch the almost-empty offset (X); holding PEN low for a second LDCK↑ latches the almost-full offset (Y). The SN74ACT7806-20DL defaults to X=Y=32 if PEN remains high, and AF/AE asserts high when word count ≤X or ≥(256−Y).
Is the SN74ACT7806-20DL pin-compatible with other devices in the ACT78xx family?
Yes, the SN74ACT7806-20DL is explicitly pin-to-pin compatible with SN74ACT7804-20DL (128×18) and SN74ACT7814-20DL (512×18), sharing identical 56-pin DL package, pin functions, and electrical timing. This allows direct PCB reuse across depth variants without layout changes, as confirmed in the SCAS438C datasheet feature list.
What are the power supply requirements for reliable operation of the SN74ACT7806-20DL?
The SN74ACT7806-20DL requires a single 4.5 V to 5.5 V supply (VCC) with ±5 µA input leakage and 400 µA typical ICC. It is characterized for 0°C to 70°C operation and specifies VOL ≤ 0.5 V at IOL = 16 mA, ensuring robust noise margins in 5-V systems. Decoupling with 0.1 µF ceramic capacitors near VCC/GND pins is recommended per TI layout guidelines.
Can the SN74ACT7806-20DL be used in systems requiring fail-safe reset behavior?
Yes - the SN74ACT7806-20DL mandates RESET assertion at power-up to initialize internal stack pointers and set FULL high, EMPTY low, and HF low. The RESET input is asynchronous and active-low, with a minimum pulse width of 10 ns ('20 speed grade). This ensures deterministic startup state and prevents undefined flag behavior, making it suitable for safety-critical boot sequences.
SN74ACT7806-20DL Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74ACT
- Package/Case:
- 56-BSSOP (0.295", 7.50mm Width)
- Packaging:
- Bulk
- Product Status:
- Active
- Programmable:
- Not Verified
- Memory Size:
- 4.5K (256 x 18)
- Function:
- Asynchronous
- Data Rate:
- 50MHz
- Access Time:
- 15ns
- Voltage - Supply:
- 4.5 V ~ 5.5 V
- Current - Supply (Max):
- 400µA
- Bus Directional:
- Uni-Directional
- Expansion Type:
- Width
- Programmable Flags Support:
- Yes
- Retransmit Capability:
- No
- FWFT Support:
- No
- Operating Temperature:
- 0°C ~ 70°C
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 56-SSOP
SN74ACT7806-20DL FAQ
1.How can I place an order for SN74ACT7806-20DL through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74ACT7806-20DL 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 SN74ACT7806-20DL reliable?
The price and inventory of SN74ACT7806-20DL are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74ACT7806-20DL is usually 5 days.
3.What payment methods are accepted for SN74ACT7806-20DL?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74ACT7806-20DL transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74ACT7806-20DL?
SN74ACT7806-20DL orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74ACT7806-20DL 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 SN74ACT7806-20DL?
For technical support, including SN74ACT7806-20DL datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74ACT7806-20DL requirements.
6.How does Aetrix verify that SN74ACT7806-20DL is sourced from the original manufacturer or authorized distributors?
All SN74ACT7806-20DL 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 SN74ACT7806-20DL meets industry standards.
7.What is the process for return or replacement of SN74ACT7806-20DL?
All SN74ACT7806-20DL units undergo pre-shipment inspection (PSI). If there is an issue with SN74ACT7806-20DL, 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 SN74ACT7806-20DL part is unused and in its original packaging.
Return procedure for SN74ACT7806-20DL:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SN74ACT7806-20DL Tags
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