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Texas Instruments SN74ACT7806-20DLR
- Part No.:
- SN74ACT7806-20DLR
- Manufacturer:
- Texas Instruments
- Category:
- FIFOs Memory
- Package:
- 56-BSSOP (0.295", 7.50mm Width)
- Datasheet:
-
SN74ACT7806-20DLR.pdf
- Description:
- IC FIFO ASYNC 256X18 56SSOP
- Quantity:
- Payment:
- Shipping:
Inventory:1,955
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Product details
Overview
SN74ACT7806-20DLR from Texas Instruments is a 256 × 18-bit strobed FIFO memory IC with 15 ns access time, 50 MHz maximum clock frequency, and programmable almost-full/almost-empty flags. It operates at 4.5–5.5 V, supports independent load/unload clocks, and delivers simultaneous 18-bit parallel data transfer for high-speed buffering in digital interface bridging applications.
For engineers reviewing the SN74ACT7806-20DLR datasheet, SN74ACT7806-20DLR pinout, SN74ACT7806-20DLR application, or SN74ACT7806-20DLR equivalent, key selection criteria include its 56-pin SSOP package, asynchronous dual-clock operation, full/empty/half-full status flags, and compatibility with TI's Widebus™ family for width-expansion designs.
Technical Context
The SN74ACT7806-20DLR implements a synchronous 256-word × 18-bit SRAM-based FIFO with separate rising-edge-triggered LDCK and UNCK inputs. Its internal stack pointers track write/read depth, enabling real-time status flag generation (FULL, EMPTY, HF, AF/AE) without external logic.
Flag behavior is deterministic: FULL goes low at 256 words written, EMPTY goes low when zero words remain, HF asserts high at ≥128 words, and AF/AE is programmable via D0–D6 during reset-initiated setup with PEN control-supporting custom buffer-threshold management.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Depth × Width | 256 words × 18 bits - provides 4,608-bit buffer capacity for burst-mode data alignment between mismatched clock domains. |
| Access Time | 15 ns - enables sub-67 MHz timing margin for reliable 50 MHz operation with 50-pF load on all Q outputs. |
| Max Clock Frequency | 50 MHz - supports high-throughput serial-to-parallel bridging in telecom and test equipment interfaces. |
| Supply Voltage | 4.5 V to 5.5 V - ensures compatibility with standard 5-V TTL/CMOS systems and noise-immune operation. |
| Status Flags | FULL, EMPTY, HF, AF/AE - deliver real-time buffer occupancy monitoring without host CPU polling overhead. |
| Output Drive | 16 mA sink / –8 mA source - drives standard 50-pF loads directly, eliminating need for external bus buffers. |
| Operating Temperature | 0°C to 70°C - qualified for commercial-grade embedded systems including industrial controllers and instrumentation. |
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 logic and flag states. |
| 2–9, 11–14 (D0–D17) | 18-bit parallel data input | Accepts data on LDCK rising edge; D0–D6 used to program AF/AE offsets when PEN is low post-reset. |
| 22 (HF) | Half-full status output | High when ≥128 words stored; enables mid-buffer interrupt handling in DMA-controlled systems. |
| 23 (PEN) | AF/AE programming enable | Low during first two LDCK edges after reset latches D0–D6 as X/Y offset values for custom flag thresholds. |
| 24 (AF/AE) | Programmable status flag | High when words ≤ X or ≥ (256–Y); default X=Y=32 unless reprogrammed, supporting adaptive flow control. |
| 25 (LDCK) | Load clock input | Rising edge writes data into FIFO; disabled when FULL is low, preventing overflow corruption. |
| 28 (FULL) | Full status output | Active-low signal indicating no further writes accepted; synchronizes upstream data source throttling. |
| 29 (EMPTY) | Empty status output | Active-low signal indicating no valid reads possible; gates UNCK to prevent underflow glitches. |
| 32 (UNCK) | Unload clock input | Rising edge reads data from FIFO; disabled when EMPTY is low, ensuring deterministic read availability. |
| 33–34, 36–38, 40–43, 45–49, 51, 53–55 (Q0–Q17) | 18-bit parallel data output | Non-inverting outputs placed in high-Z when OE is high; support hot-swap and bus-sharing configurations. |
| 56 (OE) | Output enable input | High disables all Q outputs; allows multiple FIFOs to share a common data bus without contention. |
Key Features
| Feature | Design Value |
|---|---|
| Strobed dual-clock architecture | Independent LDCK and UNCK inputs allow fully asynchronous read/write operations across different clock domains with no handshake logic required. |
| Programmable AF/AE flag | Customizable almost-full/almost-empty thresholds (X/Y = 0–127) enable precise buffer management for variable-rate streaming protocols. |
| Full set of status flags | FULL, EMPTY, HF, and AF/AE provide immediate visibility into FIFO occupancy-reducing software polling and enabling hardware-triggered interrupts. |
| Pin-to-pin compatibility | Direct replacement for SN74ACT7804 (128×18) and SN74ACT7814 (512×18) within same DL package-simplifies design scaling and migration. |
| Low-power advanced CMOS | ICC ≤ 400 µA typical at 5.5 V enables integration into power-sensitive systems without thermal derating concerns. |
Applications
| Telecom Line Interface | Digital Test Equipment |
|---|---|
Use Scenario: Buffering T1/E1 frame data between line-side serializer and system-side processor operating at different clock rates. IC Role / Device Role / Timing Role: Strobed FIFO providing elastic storage to absorb clock domain skew and jitter between physical layer and MAC layer. Use Value: Eliminates bit slips and frame loss by decoupling 1.544 MHz/2.048 MHz line clocks from internal 50 MHz system clock using deterministic 15 ns access latency. |
Use Scenario: Capturing high-speed digital stimulus/response patterns during automated functional testing of ASICs and FPGAs. IC Role / Device Role / Timing Role: High-bandwidth data capture buffer that accepts parallel test vectors at 50 MHz and releases them to slower analysis logic. Use Value: Enables real-time pattern acquisition without dead time, leveraging 256×18 depth and simultaneous 18-bit output switching for full-word visibility. |
| Industrial PLC Backplane Bridge | Video Frame Synchronizer |
Use Scenario: Interfacing legacy 8-bit I/O modules with modern 18-bit fieldbus controllers over shared backplane with timing mismatches. IC Role / Device Role / Timing Role: Width- and rate-adaptive FIFO used in conjunction with SN74ACT7806 devices to expand to 256×36 (Figure 6). Use Value: Supports seamless word-width expansion while maintaining independent clock domains-critical for deterministic scan-cycle timing in safety-critical control loops. |
Use Scenario: Aligning asynchronous video streams (e.g., HDMI input vs. display engine clock) to eliminate frame tearing and stutter. IC Role / Device Role / Timing Role: Dual-clock FIFO absorbing pixel data bursts and releasing them at display refresh rate with programmable AF/AE thresholds. Use Value: Prevents visual artifacts by triggering early readout when buffer reaches (256–Y) words, ensuring continuous pixel pipeline feeding under variable load. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar FIFO memory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74ACT7806-25DLR | Slower 25 MHz max clock, 24 ns access time; identical pinout, flags, and programming model. | Suitable for cost-sensitive designs where 50 MHz bandwidth is unnecessary; lower power consumption at reduced frequency. | Select when system clock budget permits relaxed timing margins and lower ICC is prioritized over peak throughput. |
| SN74ACT7814-20DLR | 512 × 18 memory depth, same 15 ns access and 50 MHz rating; pin-compatible but requires updated PCB layout due to different flag pin assignments (e.g., HF relocated). | Used where deeper buffering is needed to handle longer burst intervals or higher latency interfaces. | Choose only if 512-word depth is mandatory; verify HF/AF/AE pin mapping against schematic-no drop-in replacement despite shared package. |
Compared with SN74ACT7806-25DLR, the SN74ACT7806-20DLR delivers 2× higher data rate capability at identical power and footprint; versus SN74ACT7814-20DLR, it offers proven timing margin for 50 MHz operation but half the buffer depth-making it optimal for latency-constrained, moderate-burst applications.
Availability
SN74ACT7806-20DLR is available at Aetrix Electronics and suitable for telecom infrastructure, automated test equipment, industrial PLC backplanes, and video synchronization systems requiring stable component supply and long-term obsolescence management.
Supply support for SN74ACT7806-20DLR 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 SN74ACT7806-20DLR belongs to TI's Widebus™ family of advanced CMOS FIFOs, engineered specifically for high-speed, low-latency data buffering in multi-clock-domain digital systems.
FAQ
What is the maximum clock frequency supported by the SN74ACT7806-20DLR?
The SN74ACT7806-20DLR supports a maximum clock frequency of 50 MHz for both LDCK and UNCK inputs, verified under recommended operating conditions (VCC = 4.5 V to 5.5 V, TA = 0°C to 70°C). This rating is tied to its -20 speed grade and 15 ns access time specification, making SN74ACT7806-20DLR suitable for high-throughput digital interface applications requiring minimal latency.
How does the AF/AE flag programming work on the SN74ACT7806-20DLR?
After asserting RESET, the SN74ACT7806-20DLR enters programming mode when PEN is held low before the first LDCK rising edge. The binary value on D0–D6 is latched as the almost-empty offset (X) on that edge; a second LDCK edge (with PEN still low) latches D0–D6 as the almost-full offset (Y). SN74ACT7806-20DLR defaults to X=Y=32 if PEN remains high, and AF/AE asserts high when word count ≤ X or ≥ (256–Y).
Is the SN74ACT7806-20DLR pin-compatible with other FIFOs in the Widebus™ family?
Yes, the SN74ACT7806-20DLR is pin-to-pin compatible with SN74ACT7804 (128×18) and SN74ACT7814 (512×18) in the same DL package, sharing identical pin functions for D0–D17, Q0–Q17, LDCK, UNCK, RESET, OE, FULL, EMPTY, HF, AF/AE, and PEN. However, SN74ACT7814-20DLR relocates HF to a different pin, so direct substitution requires schematic validation.
What are the absolute maximum ratings for the SN74ACT7806-20DLR?
The SN74ACT7806-20DLR has an absolute maximum supply voltage of –0.5 V to 7 V, input voltage range of –0.5 V to 7 V, and storage temperature range of –65°C to 150°C. Exceeding these limits may cause permanent damage. Recommended operating conditions specify VCC = 4.5–5.5 V and TA = 0°C to 70°C-values strictly enforced in all SN74ACT7806-20DLR production testing and qualification.
Does the SN74ACT7806-20DLR support word-width expansion?
Yes, the SN74ACT7806-20DLR supports word-width expansion to 256 × 36 bits using two devices, as documented in Figure 6 of the datasheet. One SN74ACT7806-20DLR handles D0–D17/Q0–Q17, while a second manages D18–D35/Q18–Q35, sharing common LDCK, UNCK, RESET, OE, and PEN signals. Status flags must be OR'd externally for unified FULL/EMPTY reporting.
SN74ACT7806-20DLR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74ACT
- Package/Case:
- 56-BSSOP (0.295", 7.50mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- 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
SN74ACT7806-20DLR FAQ
1.How can I place an order for SN74ACT7806-20DLR through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74ACT7806-20DLR 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 SN74ACT7806-20DLR reliable?
The price and inventory of SN74ACT7806-20DLR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74ACT7806-20DLR is usually 5 days.
3.What payment methods are accepted for SN74ACT7806-20DLR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74ACT7806-20DLR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74ACT7806-20DLR?
SN74ACT7806-20DLR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74ACT7806-20DLR 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 SN74ACT7806-20DLR?
For technical support, including SN74ACT7806-20DLR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74ACT7806-20DLR requirements.
6.How does Aetrix verify that SN74ACT7806-20DLR is sourced from the original manufacturer or authorized distributors?
All SN74ACT7806-20DLR 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 SN74ACT7806-20DLR meets industry standards.
7.What is the process for return or replacement of SN74ACT7806-20DLR?
All SN74ACT7806-20DLR units undergo pre-shipment inspection (PSI). If there is an issue with SN74ACT7806-20DLR, 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 SN74ACT7806-20DLR part is unused and in its original packaging.
Return procedure for SN74ACT7806-20DLR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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