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Texas Instruments SN74ACT7804-40DL
- Part No.:
- SN74ACT7804-40DL
- Manufacturer:
- Texas Instruments
- Category:
- FIFOs Memory
- Package:
- 56-BSSOP (0.295", 7.50mm Width)
- Datasheet:
-
SN74ACT7804-40DL.pdf
- Description:
- IC FIFO ASYNC 512X18 56SSOP
- Quantity:
- Payment:
- Shipping:
Inventory:2,528
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Product details
Overview
SN74ACT7804-40DL from Texas Instruments is a 512 × 18-bit strobed FIFO memory IC designed for high-speed data buffering between asynchronous clock domains. It delivers 15 ns access time, supports up to 40 MHz clock frequency, features programmable almost-full/almost-empty flags, and operates across 0°C to 70°C with 4.5–5.5 V supply.
For engineers reviewing the SN74ACT7804-40DL datasheet, SN74ACT7804-40DL pinout, SN74ACT7804-40DL application, or SN74ACT7804-40DL equivalent, key selection criteria include its 18-bit parallel I/O width, dual independent clocks (LDCK/UNCK), status flag architecture (FULL/EMPTY/HF/AF-AE), and DL-package compatibility with space-constrained PCB layouts.
Technical Context
The SN74ACT7804-40DL implements a synchronous 512-word × 18-bit SRAM-based FIFO with independent load and unload clock paths. Its internal stack pointers track write/read positions, enabling true first-in-first-out operation without external address management.
Status logic generates FULL (active-low), EMPTY (active-low), HF (high at ≥256 words), and programmable AF/AE flags-where offset values X (almost-empty) and Y (almost-full) are latched via D0–D7 on LDCK edges under PEN control after reset.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Depth × Width | 512 words × 18 bits - provides 9.2 kbit buffer capacity for burst-mode data alignment |
| Max Clock Frequency | 40 MHz - enables sustained 720 MB/s throughput in 18-bit parallel mode |
| Access Time | 15 ns - ensures sub-cycle latency for real-time interface bridging |
| Supply Voltage | 4.5 V to 5.5 V - compatible with standard 5 V TTL/CMOS logic rails |
| Operating Temperature | 0°C to 70°C - rated for commercial-grade embedded systems and instrumentation |
| Output Drive | 16 mA sink / –8 mA source - drives 50-pF loads directly without external buffers |
| Flag Logic Levels | FULL/EMPTY active-low; HF/AF-AE active-high - simplifies direct connection to control-state machines |
Pinout & Package
Packaged in a 56-pin Shrink Small-Outline (DL) package with 300-mil body width and 25-mil center-to-center lead pitch. Pin count and layout match industry-standard DL footprint for automated assembly.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (RESET) | Asynchronous reset input | Active-low signal that clears internal pointers and forces FULL high, EMPTY low, HF low, AF/AE high |
| 2–9, 11–12, 14–21 (D0–D17) | 18-bit parallel data input | Accepts incoming data on rising edge of LDCK when FULL = high; used to program AF/AE offsets during initialization |
| 22 (HF) | Half-full status flag output | High when FIFO contains ≥256 words - enables mid-buffer flow control decisions |
| 23 (PEN) | Program enable input | Low during first two LDCK edges after reset selects D0–D7 as AF/AE offset values X and Y |
| 24 (AF/AE) | Programmable status flag output | High when word count ≤ X or ≥ (512 − Y); default X = Y = 64 unless reprogrammed |
| 25 (LDCK) | Load clock input | Rising-edge-triggered write clock; disabled when FULL = low |
| 28 (FULL) | Full status flag output | Active-low signal indicating no further writes accepted - prevents overflow in streaming interfaces |
| 29 (EMPTY) | Empty status flag output | Active-low signal indicating no valid data available - blocks invalid read cycles |
| 32 (UNCK) | Unload clock input | Rising-edge-triggered read clock; disabled when EMPTY = low |
| 33–34, 36–38, 40–43, 45–49, 51, 53–55 (Q0–Q17) | 18-bit parallel data output | Noninverting outputs placed in high-impedance state when OE = high |
| 56 (OE) | Output enable input | Active-low control for tri-state Q outputs - allows bus sharing in multi-FIFO systems |
Key Features
| Feature | Design Value |
|---|---|
| Independent Load/Unload Clocks | Enables seamless bridging between mismatched clock domains (e.g., 25 MHz video input ↔ 40 MHz display engine) |
| Programmable AF/AE Flag | Allows custom buffer watermark thresholds (X/Y = 0–255) to optimize latency vs. backpressure trade-offs |
| Full/Empty/Half-Full Flags | Provides immediate visibility into buffer occupancy without polling or external counters |
| 3-State Outputs with OE | Supports shared data buses in multi-FIFO configurations without external bus transceivers |
| Pin-to-Pin Compatibility | Direct replacement for SN74ACT7806 and SN74ACT7814 in existing DL-footprint designs |
Applications
| Video Data Buffering | Industrial Serial Protocol Bridge |
|---|---|
|
Use Scenario: Synchronizing pixel data between a 60 Hz camera sensor and a 75 Hz display controller. IC Role / Device Role / Timing Role: Strobed FIFO memory acting as a clock-domain crossing buffer with independent LDCK (sensor clock) and UNCK (display clock). Use Value: Eliminates frame drops by absorbing timing jitter; HF flag triggers DMA prefetch at 50% fill level to maintain continuous stream. |
Use Scenario: Bridging RS-485 Modbus RTU frames to a UART-based microcontroller with different baud rates. IC Role / Device Role / Timing Role: Asynchronous data buffer decoupling master/slave communication timing, using FULL/EMPTY flags for hardware handshaking. Use Value: Prevents UART overrun/underrun; programmable AF/AE allows tuning buffer thresholds to match variable packet sizes. |
| Test Equipment Pattern Memory | Digital Audio Sample Rate Converter |
|
Use Scenario: Storing and replaying digital test vectors in automated circuit testers with variable pattern generation rates. IC Role / Device Role / Timing Role: High-speed FIFO providing deterministic delay and rate adaptation between pattern generator and DUT interface clocks. Use Value: 15 ns access time ensures minimal skew; 18-bit width matches common digital I/O bus widths for bit-accurate vector storage. |
Use Scenario: Aligning 44.1 kHz audio samples from CD playback with a 48 kHz DAC clock in consumer audio gear. IC Role / Device Role / Timing Role: Dual-clock FIFO absorbing sample-rate difference while maintaining zero-latency playback path. Use Value: HF and AF/AE flags drive adaptive clock recovery logic; 512-word depth accommodates worst-case resampling jitter. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar FIFO memory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74ACT7806-40DL | Same 512 × 18 architecture, identical pinout and timing, but fixed 64-word AF/AE offsets (non-programmable) | Lacks runtime programmability of almost-full/almost-empty thresholds | Select when simplified flag behavior suffices and design reuse of legacy SN74ACT7806 layout is required |
| SN74ACT7814-40DL | Same 512 × 18 structure and DL package, but includes additional status register accessible via serial interface | Offers enhanced diagnostics via SPI-like control port, increasing pin count and firmware overhead | Choose when real-time monitoring of FIFO depth or error flags beyond basic status pins is needed |
Compared with SN74ACT7806-40DL, the SN74ACT7804-40DL adds programmable AF/AE offsets for adaptive flow control; versus SN74ACT7814-40DL, it trades serial configurability for lower pin count and simpler hardware integration.
Availability
SN74ACT7804-40DL is available at Aetrix Electronics and suitable for video buffering, industrial protocol bridging, test equipment pattern memory, and digital audio sample rate conversion requiring stable component supply and long-term obsolescence mitigation.
Supply support for SN74ACT7804-40DL 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 SN74ACT7804-40DL belongs to TI's Widebus™ family of high-speed logic devices, engineered specifically for low-latency, high-throughput data buffering in mixed-clock-domain systems.
FAQ
What is the maximum operating clock frequency of the SN74ACT7804-40DL?
The SN74ACT7804-40DL is rated for a maximum clock frequency of 40 MHz on both LDCK and UNCK inputs under recommended operating conditions (VCC = 4.5 V to 5.5 V, TA = 0°C to 70°C). This rating is confirmed by timing specifications in the SCAS204C datasheet, where tw (pulse duration) is specified as 12 ns minimum, supporting reliable 40 MHz operation.
How does the programmable AF/AE flag function in the SN74ACT7804-40DL?
The AF/AE flag in the SN74ACT7804-40DL becomes programmable after reset: with PEN held low, the first LDCK rising edge latches D0–D7 as the almost-empty offset X, and a second LDCK edge latches Y for almost-full. The flag goes high when word count ≤ X or ≥ (512 − Y). Default values are X = Y = 64 if PEN remains high.
Is the SN74ACT7804-40DL pin-compatible with other FIFO devices in the same family?
Yes, the SN74ACT7804-40DL is explicitly stated as pin-to-pin compatible with SN74ACT7806-40DL and SN74ACT7814-40DL in the datasheet. All three share identical DL-package pinout, terminal functions, and power/ground assignments, enabling drop-in substitution where functional requirements align.
What are the voltage and temperature specifications for the SN74ACT7804-40DL?
The SN74ACT7804-40DL operates from 4.5 V to 5.5 V supply voltage and is characterized for ambient temperatures from 0°C to 70°C. Absolute maximum ratings allow VCC up to 7 V and storage from –65°C to +150°C, but functional operation is guaranteed only within the recommended ranges specified in the SCAS204C datasheet.
Does the SN74ACT7804-40DL support word-width expansion?
Yes, the SN74ACT7804-40DL supports word-width expansion as documented in Figure 6 of the datasheet. Two SN74ACT7804-40DL devices can be cascaded to implement a 512 × 36-bit FIFO by connecting LDCK/UNCK in parallel and routing D0–D17/Q0–Q17 across both units with appropriate FULL/EMPTY flag arbitration.
SN74ACT7804-40DL 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:
- 9K (512 x 18)
- Function:
- Asynchronous
- Data Rate:
- 25MHz
- Access Time:
- 20ns
- 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
SN74ACT7804-40DL FAQ
1.How can I place an order for SN74ACT7804-40DL through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74ACT7804-40DL 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 SN74ACT7804-40DL reliable?
The price and inventory of SN74ACT7804-40DL are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74ACT7804-40DL is usually 5 days.
3.What payment methods are accepted for SN74ACT7804-40DL?
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4.How is shipping managed for SN74ACT7804-40DL?
SN74ACT7804-40DL orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74ACT7804-40DL 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 SN74ACT7804-40DL?
For technical support, including SN74ACT7804-40DL datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74ACT7804-40DL requirements.
6.How does Aetrix verify that SN74ACT7804-40DL is sourced from the original manufacturer or authorized distributors?
All SN74ACT7804-40DL 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 SN74ACT7804-40DL meets industry standards.
7.What is the process for return or replacement of SN74ACT7804-40DL?
All SN74ACT7804-40DL units undergo pre-shipment inspection (PSI). If there is an issue with SN74ACT7804-40DL, 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 SN74ACT7804-40DL part is unused and in its original packaging.
Return procedure for SN74ACT7804-40DL:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SN74ACT7804-40DL Tags
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