My Inquiry
My Account
Texas Instruments SN74ACT3651-30PCB
- Part No.:
- SN74ACT3651-30PCB
- Manufacturer:
- Texas Instruments
- Category:
- FIFOs Memory
- Package:
- 120-LQFP
- Datasheet:
-
SN74ACT3651-30PCB.pdf
- Description:
- IC FIFO SYNC 2KX36 120HLQFP
- Quantity:
- Payment:
- Shipping:
Inventory:4,454
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
SN74ACT3651-30PCB from Texas Instruments is a 2048 × 36-bit clocked FIFO memory IC with dual asynchronous ports (A/B), 67 MHz max clock frequency, 11 ns read access time, and synchronous retransmit capability - used for high-speed data buffering between mismatched bus domains in telecom line cards and DSP-based signal processing systems.
For engineers reviewing the SN74ACT3651-30PCB datasheet, SN74ACT3651-30PCB pinout, SN74ACT3651-30PCB application, or SN74ACT3651-30PCB equivalent, key selection criteria include programmable almost-full/empty flag offsets, mailbox register support for control-message handshaking, dual-port synchronization tolerance, and compatibility with microprocessor interfaces requiring CLKA/CLKB domain isolation.
Technical Context
The SN74ACT3651-30PCB implements a 2048-word × 36-bit dual-port SRAM FIFO with independent free-running clocks (CLKA and CLKB), enabling asynchronous data transfer between port A and port B. Its two-stage synchronized flags (IR/AF on CLKA; OR/AE on CLKB) mitigate metastability across clock domains.
It integrates mailbox registers (Mail1/Mail2) for sideband control messaging, supports three flag-offset programming modes (preset, parallel load via Port A, serial load via FS0/SD), and features retransmit mode (RTM/RFM) for repeatable data streaming - all built in low-power 0.8-µm Advanced CMOS technology.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Depth × Width | 2048 × 36 bits - provides 73.7 kB of buffered storage for burst-to-continuous data rate conversion. |
| Max Clock Frequency | 67 MHz - enables real-time buffering in high-throughput digital communications links. |
| Read Access Time | 11 ns - ensures minimal latency when feeding data to downstream logic or ADC/DAC interfaces. |
| Flag Synchronization | Two-stage flip-flop sync per port - reduces metastability risk when CLKA and CLKB operate asynchronously. |
| Operating Temperature | 0°C to 70°C - validated for commercial-grade embedded systems including industrial controllers and test equipment. |
| Technology Node | 0.8-µm Advanced CMOS - delivers low static power and rail-to-rail TTL-compatible I/O levels. |
| Programmable Flags | Almost-full (AF) and almost-empty (AE) with user-defined offsets (1–2044) - enables precise flow-control tuning for custom buffer management. |
Pinout & Package
SN74ACT3651-30PCB uses a 120-pin Thin Quad Flat Package (TQFP), designated PCB in TI documentation. Pin numbering follows standard top-view layout with VCC/GND distributed across multiple pins for noise suppression and thermal stability.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0–A35 | Port-A bidirectional data bus | 36-bit interface for write/read operations on side A; high-impedance when CSA or W/RA is inactive. |
| B0–B35 | Port-B bidirectional data bus | 36-bit interface for write/read operations on side B; active only when CSB = L and W/RB = H. |
| CLKA / CLKB | Free-running port clocks | Independent synchronous timing references; IR/AF tied to CLKA edge; OR/AE tied to CLKB edge. |
| ENA / ENB | Port master enable inputs | Global gating signals - disable all port activity when low, regardless of chip select or R/W state. |
| CSA / CSB | Port chip select inputs | Enable port I/O drivers only when low; isolate bus during multi-device sharing. |
| W/RA / W/RB | Port write/read direction controls | W/RA high = write; W/RB low = write - polarity asymmetry simplifies microprocessor bus interfacing. |
| IR / OR | Synchronized status flags | IR low = FIFO full (write blocked); OR high = valid data ready at output register. |
| AF / AE | Programmable threshold flags | AF low = ≤ Y empty locations remain; AE low = ≤ X words stored - configurable via FS0/FS1 reset sequence. |
| MBA / MBB | Mailbox select inputs | Select Mail1 (A-side) or Mail2 (B-side) bypass registers instead of FIFO core for command/data exchange. |
| RTM / RFM | Retransmit control inputs | RTM high initiates retransmit mode; RFM high triggers re-read from marked location - enables FIR filter coefficient replay. |
| RST | Asynchronous reset input | Requires ≥4 CLKA + ≥4 CLKB rising edges while low - initializes pointers, clears flags, and loads offset registers. |
| FS0/SD / FS1/SEN | Flag-offset programming interface | Dual-function pins: configure preset (8/64), parallel load, or 22-bit serial load of AF/AE offset values. |
Key Features
| Feature | Design Value |
|---|---|
| Synchronous retransmit mode | Enables repeatable reading from any FIFO location without destroying original data - critical for FIR filtering and protocol replay. |
| Dual 36-bit mailbox registers | Provides dedicated sideband channels for handshake messages (e.g., DMA descriptors, interrupt requests) independent of main FIFO flow. |
| Three flag-offset programming methods | Supports rapid system bring-up (preset 8/64), FPGA-hosted configuration (parallel load), or low-pin-count microcontroller setup (serial load). |
| Metastability-hardened flag outputs | Two-stage synchronization per clock domain eliminates timing uncertainty in asynchronous clock boundary crossings. |
| Pin-to-pin compatibility | Direct replacement for SN74ACT3631 and SN74ACT3641 - allows design reuse across FIFO depth variants (1024×36, 4096×36). |
Applications
| DSP-Based FIR Filtering | Telecom Line Card Buffering |
|---|---|
Use Scenario: Real-time digital filtering of sampled voice/data streams using fixed-coefficient FIR algorithms. IC Role / Device Role / Timing Role: Clocked FIFO providing synchronized coefficient replay and sample buffering between ADC and DSP cores. Use Value: Retransmit mode enables deterministic coefficient reloading without CPU intervention; mailbox registers pass filter tap updates between processors. |
Use Scenario: Bridging data between TDM backplane (64 Mbps) and packet-switched Ethernet interface (100 Mbps) in access concentrators. IC Role / Device Role / Timing Role: Asynchronous FIFO decoupling clock domains while maintaining zero-data-loss throughput under burst traffic. Use Value: Programmable AF/AE flags allow dynamic buffer watermarking to prevent overflow/underflow during link congestion or jitter events. |
| Industrial Motion Controller Interface | Test Equipment Data Capture |
Use Scenario: Coordinating position feedback (encoder) and command output (PWM) streams in closed-loop servo drives. IC Role / Device Role / Timing Role: Dual-port FIFO isolating real-time motion controller clock (CLKA) from host PC interface clock (CLKB). Use Value: Mailbox registers convey motion commands and fault status; synchronized flags ensure deterministic handshake timing across domains. |
Use Scenario: Capturing high-speed analog waveform samples into memory for post-processing in automated test systems. IC Role / Device Role / Timing Role: High-bandwidth FIFO buffering ADC output before transfer to host via PCI or USB bridge. Use Value: 11 ns access time minimizes dead time between samples; 67 MHz clock support matches fast SAR ADCs and pipeline digitizers. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar clocked FIFO applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74ACT3641-30PCB | Same package and pinout; 4096 × 36 memory depth (2× capacity); identical flag logic and retransmit architecture. | Better suited for longer latency buffers or deeper pipeline staging where >2k words required. | Select when larger buffer depth is needed without changing PCB layout or firmware interface. |
| SN74ACT3631-30PCB | Same package and pinout; 1024 × 36 memory depth (½ capacity); otherwise functionally identical flag/control set. | Optimized for space-constrained designs or lower-latency buffering where 1k words suffice. | Choose for cost-sensitive or compact applications where reduced depth meets timing budget. |
Compared with SN74ACT3641-30PCB and SN74ACT3631-30PCB, the SN74ACT3651-30PCB offers optimal balance of depth (2048 words), speed (67 MHz), and footprint - making it ideal for mid-range buffering where neither minimal nor maximal depth is required.
Availability
SN74ACT3651-30PCB is available at Aetrix Electronics and suitable for telecom infrastructure, DSP subsystems, industrial motion control, and automated test equipment requiring stable component supply and long-term obsolescence planning.
Supply support for SN74ACT3651-30PCB 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 over 50 years of innovation in high-reliability timing and interface ICs.
The SN74ACT3651-30PCB belongs to TI's legacy ACT-family clocked FIFO product line, designed specifically for high-speed, low-latency data buffering in mixed-clock-domain systems such as communications infrastructure and real-time signal processing.
FAQ
What is the maximum supported clock frequency for SN74ACT3651-30PCB?
The SN74ACT3651-30PCB supports clock frequencies up to 67 MHz on both CLKA and CLKB inputs. This rating is specified under commercial temperature conditions (0°C to 70°C) and applies to guaranteed read/write timing performance, including 11 ns access time and proper flag synchronization behavior.
How does the retransmit mode work in SN74ACT3651-30PCB?
In SN74ACT3651-30PCB, retransmit mode is activated by raising RTM while OR is high, marking the current FIFO output register content as the first retransmit word. Subsequent reads cycle through FIFO contents starting from that point. RFM allows restarting from the marked location - essential for FIR coefficient replay and protocol message retransmission.
Can SN74ACT3651-30PCB operate with completely asynchronous CLKA and CLKB?
Yes, SN74ACT3651-30PCB is explicitly designed for asynchronous operation: CLKA and CLKB may run at different frequencies, phases, or even be stopped independently. Its two-stage synchronized flags (IR/AF on CLKA; OR/AE on CLKB) ensure reliable status reporting across clock domains without external synchronizers.
What are the programming options for the almost-full and almost-empty flags in SN74ACT3651-30PCB?
SN74ACT3651-30PCB supports three AF/AE offset programming methods selected at reset: preset values (8 or 64), parallel load from Port A (two writes to load Y then X), or serial load via FS0/SD (22-bit sequence). All methods allow offsets from 1 to 2044, enabling precise buffer-level thresholds for custom flow control.
Is SN74ACT3651-30PCB pin-compatible with other devices in the same family?
Yes, SN74ACT3651-30PCB is pin-to-pin compatible with SN74ACT3631-30PCB (1024×36) and SN74ACT3641-30PCB (4096×36) in the same 120-pin PCB package. This allows direct substitution based on memory depth requirements without PCB redesign or firmware changes to the control interface.
SN74ACT3651-30PCB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74ACT
- Package/Case:
- 120-LQFP
- Packaging:
- Tray
- Product Status:
- Obsolete
- Programmable:
- Not Verified
- Memory Size:
- 72K (2K x 36)
- Function:
- Synchronous
- Data Rate:
- 33.4MHz
- Access Time:
- 15ns
- Voltage - Supply:
- 4.5 V ~ 5.5 V
- Current - Supply (Max):
- 400µA
- Bus Directional:
- Bi-Directional
- Expansion Type:
- Depth, Width
- Programmable Flags Support:
- Yes
- Retransmit Capability:
- Yes
- FWFT Support:
- No
- Operating Temperature:
- 0°C ~ 70°C
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 120-HLQFP (14x14)
SN74ACT3651-30PCB FAQ
1.How can I place an order for SN74ACT3651-30PCB through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74ACT3651-30PCB 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 SN74ACT3651-30PCB reliable?
The price and inventory of SN74ACT3651-30PCB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74ACT3651-30PCB is usually 5 days.
3.What payment methods are accepted for SN74ACT3651-30PCB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74ACT3651-30PCB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74ACT3651-30PCB?
SN74ACT3651-30PCB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74ACT3651-30PCB 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 SN74ACT3651-30PCB?
For technical support, including SN74ACT3651-30PCB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74ACT3651-30PCB requirements.
6.How does Aetrix verify that SN74ACT3651-30PCB is sourced from the original manufacturer or authorized distributors?
All SN74ACT3651-30PCB 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 SN74ACT3651-30PCB meets industry standards.
7.What is the process for return or replacement of SN74ACT3651-30PCB?
All SN74ACT3651-30PCB units undergo pre-shipment inspection (PSI). If there is an issue with SN74ACT3651-30PCB, 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 SN74ACT3651-30PCB part is unused and in its original packaging.
Return procedure for SN74ACT3651-30PCB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SN74ACT3651-30PCB Tags
-
7201LA15JGI
Renesas
-
7204L12JG
Renesas
-
72V82L15PAG8
Renesas
-
7205L15JGI
Renesas
-
7208L20JG
Renesas
-
72V2105L10PFG
Renesas
-
72V2111L15PFGI
Renesas
-
72V2113L6PFG
Renesas
-
72V36110L6PFG
Renesas
-
SN74ALVC7804-40DL
Texas Instruments
-
7202LA25JGI
Renesas
-
SN74V245-15PAG
Texas Instruments
Tech Hub
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…
Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…
Jumper cables guide covering safe connection order, red and black clamp placement, final ground connection, cable gauge, length, clamp quality, copper vs CCA cables, jump starter comparison and battery…
