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Renesas 74FCT621ATSOG8
- Part No.:
- 74FCT621ATSOG8
- Manufacturer:
- Renesas
- Package:
- 20-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
74FCT621ATSOG8.pdf
- Description:
- IC TXRX NON-INVERT 5.25V 20SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:1,663
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Product details
Overview
74FCT621ATSOG8 from Renesas Electronics (formerly IDT) is an octal bus transceiver with open-drain outputs in both A→B and B→A directions, designed for asynchronous bidirectional data bus interfacing. It operates at 5V ±5%, supports industrial temperature range (–40°C to +85°C), sinks up to 64mA per B-bus output, and features TTL-compatible inputs/outputs with VOH = 3.3V (typ.) and VOL = 0.3V (typ.). It enables live insertion via power-off disable outputs.
For engineers reviewing the 74FCT621ATSOG8 datasheet, 74FCT621ATSOG8 pinout, 74FCT621ATSOG8 application, or 74FCT621ATSOG8 equivalent, key selection criteria include open-drain bidirectional drive capability, 64mA B-bus sink current, JEDEC 18 compliance, SOIC-20 package compatibility, and industrial-grade thermal performance.
Technical Context
The 74FCT621ATSOG8 implements dual-directional bus communication using two independent enable controls (GBA and GAB), allowing selective activation of A-to-B or B-to-A data flow without bus contention. Its open-drain architecture requires external pull-ups and supports wired-AND logic, level translation, and hot-swap operation.
It meets JEDEC Standard 18 for TTL compatibility and delivers propagation delays as low as 1.5ns (tPHL, B→A) and 5.5ns (tPLH, A→B) under CL = 50pF and RL = 500Ω conditions. Quiescent ICC is ≤1mA, and input leakage remains ≤±1µA across the full industrial temperature range.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC Supply | 5.0V ±5% - fixed single-rail operation; no internal regulation required |
| Operating Temp | –40°C to +85°C - qualified for industrial environments without derating |
| B-Bus Sink Current | 64mA per output - drives ≥15 standard TTL loads or high-capacitance buses |
| A-Bus Sink Current | 48mA per output - lower drive strength optimized for reduced noise on A-side |
| tPLH / tPHL | 5.5ns / 1.5ns min (B→A) - enables sub-10ns asynchronous bus handshaking |
| Input Leakage | ≤±1µA max - ensures stable logic levels with high-impedance or floating bus segments |
| JEDEC Compliance | Meets Std. 18 - guarantees interoperability with legacy TTL and CMOS systems |
Pinout & Package
Package: 20-pin SOIC (SO-20, body width 7.5mm, JEDEC MS-013), RoHS-compliant, green molding compound.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 19 | GAB, GBA | Active-low enable inputs controlling direction: GAB enables B→A, GBA enables A→B |
| 2–9, 11–18 | A1–A8, B1–B8 | Open-drain bidirectional I/Os - require external pull-up resistors; tolerate VCC+0.5V |
| 10 | GND | Ground reference for all signals and power return path |
| 20 | VCC | 5V supply rail - powers internal logic; decoupling capacitor required near pin |
Key Features
| Feature | Design Value |
|---|---|
| Open-drain bidirectional I/O | Enables wired-AND arbitration, level shifting between 3.3V and 5V domains, and shared bus topology |
| Live-insertion support | Outputs enter high-impedance state when VCC = 0V - prevents back-driving during hot-plug operations |
| TTL-compatible interface | VIH = 2.0V min, VIL = 0.8V max - interoperates directly with 74LS, 74ALS, and microcontroller GPIOs |
| Low dynamic power | ICCD = 0.15–0.25 mA/MHz - reduces switching noise and heat in high-frequency bus toggling |
| Industrial reliability | Specified over –40°C to +85°C with 150°C max storage temp - suitable for factory automation and transportation systems |
Applications
| Industrial PLC Backplane Interface | Legacy System Bus Extender |
|---|---|
Use Scenario: Interfacing modular I/O cards to a central controller bus in programmable logic controllers. IC Role / Device Role / Timing Role: Bidirectional open-drain transceiver isolating card-local and backplane buses while supporting hot-swap insertion. Use Value: 64mA B-bus sink current drives long backplane traces; power-off disable prevents bus contention during module replacement. | Use Scenario: Extending TTL-level parallel control buses between aging mainframes and modern peripheral modules. IC Role / Device Role / Timing Role: Level-shifting and fan-out buffer enabling 5V TTL signal integrity across extended distances. Use Value: VOH = 3.3V (typ.) and VOL = 0.3V (typ.) meet TTL thresholds; 10pF typical input capacitance minimizes timing skew. |
| Automotive Diagnostic Tool Adapter | Test Equipment Bus Multiplexer |
Use Scenario: Adapting J1939 or SAE J1708 physical layer signals to microcontroller UART peripherals in handheld diagnostic tools. IC Role / Device Role / Timing Role: Open-drain translator converting 5V bus signals to 3.3V logic-safe levels with controlled slew rate. Use Value: Input hysteresis (200mV) rejects noise on noisy vehicle chassis grounds; industrial temp rating ensures field reliability. | Use Scenario: Sharing a single test controller's data bus among multiple DUTs using enable-controlled directional routing. IC Role / Device Role / Timing Role: Asynchronous bidirectional switch enabling time-multiplexed access to multiple device under test interfaces. Use Value: Independent GBA/GAB enables precise timing control of A↔B data flow; 1.5ns tPHL supports >100MHz bus arbitration cycles. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar octal bus transceiver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74FCT621CTSO | Same function and pinout; commercial temp range (0°C to +70°C); higher ICC (max 2mA vs 1mA) | Limited to non-industrial environments; not qualified for extended thermal cycling | Select when cost sensitivity outweighs environmental ruggedness requirements |
| 74LCX623MTCX | 3.3V-only supply (2.7–3.6V); push-pull (not open-drain) outputs; different enable logic (active-high) | Requires level-shifting for 5V systems; incompatible with wired-AND or hot-swap use cases | Choose only for new 3.3V designs where open-drain functionality is unnecessary |
Compared with SN74FCT621CTSO and 74LCX623MTCX, the 74FCT621ATSOG8 uniquely combines industrial temperature rating, true open-drain bidirectionality, and 5V TTL compatibility-making it irreplaceable in legacy bus extension and hot-pluggable industrial subsystems.
Availability
74FCT621ATSOG8 is available at Aetrix Electronics and suitable for industrial PLC backplanes, automotive diagnostic adapters, and legacy system bus extenders requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for 74FCT621ATSOG8 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
Renesas Electronics Corporation is a global semiconductor leader delivering microcontrollers, analog, power, and connectivity solutions for automotive, industrial, infrastructure, and IoT applications.
The 74FCT621ATSOG8 belongs to Renesas' legacy IDT fast CMOS logic family, engineered specifically for robust, low-noise, high-drive bidirectional bus interfacing in mission-critical industrial and transportation systems.
FAQ
What is the maximum sink current per output on the B bus of the 74FCT621ATSOG8?
The 74FCT621ATSOG8 supports up to 64mA DC sink current per B-bus output (B1–B8) under VCC = 5.0V min and TA = –40°C to +85°C. This rating allows direct driving of multiple TTL loads or termination of high-capacitance backplane traces without external buffers. The A-bus outputs are rated for 48mA, reflecting asymmetric drive optimization.
Does the 74FCT621ATSOG8 support live insertion, and how is it implemented?
Yes, the 74FCT621ATSOG8 supports live insertion through its power-off disable feature. When VCC = 0V, all outputs enter a high-impedance state regardless of input states, preventing back-driving of powered bus segments. This behavior is confirmed by IOFF leakage ≤±1µA at VCC = 0V and VIN/VO = –4.5V, enabling safe hot-plug operation in modular industrial systems.
What are the voltage thresholds for logic HIGH and LOW inputs on the 74FCT621ATSOG8?
The 74FCT621ATSOG8 specifies VIH (min) = 2.0V and VIL (max) = 0.8V under industrial conditions (VCC = 5.0V ±5%, TA = –40°C to +85°C). These values ensure reliable recognition of standard TTL logic levels. Input hysteresis is 200mV, improving noise immunity on electrically noisy industrial buses where the 74FCT621ATSOG8 is commonly deployed.
Is the 74FCT621ATSOG8 pin-compatible with other members of the IDT74FCT621 family?
Yes, the 74FCT621ATSOG8 shares identical pinout and function with IDT74FCT621T and IDT74FCT621AT variants. All use the same SOIC-20 package and pin mapping, differing only in temperature grade (industrial vs commercial) and ordering suffix. No PCB layout changes are needed when substituting within this family, provided thermal and timing margins remain acceptable.
What package type and RoHS status does the 74FCT621ATSOG8 have?
The 74FCT621ATSOG8 is supplied in a 20-pin Small Outline IC (SOIC) package per JEDEC MS-013, with 7.5mm body width and green (lead-free) molding compound. It is RoHS-compliant and marked with "G" in the ordering code (74FCT621ATSOG8), confirming exemption from lead-based solder requirements per EU Directive 2011/65/EU.
74FCT621ATSOG8 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Renesas
- Series:
- 74FCT
- Package/Case:
- 20-SOIC (0.295", 7.50mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Logic Type:
- Transceiver, Non-Inverting
- Number of Elements:
- 1
- Number of Bits per Element:
- 8
- Input Type:
- -
- Output Type:
- Open Drain
- Current - Output High, Low:
- -, 48mA; -, 64mA
- Voltage - Supply:
- 4.75V ~ 5.25V
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-SOIC
74FCT621ATSOG8 FAQ
1.How can I place an order for 74FCT621ATSOG8 through Aetrix?
Please submit a Request for Quotation (RFQ) for 74FCT621ATSOG8 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 74FCT621ATSOG8 reliable?
The price and inventory of 74FCT621ATSOG8 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 74FCT621ATSOG8 is usually 5 days.
3.What payment methods are accepted for 74FCT621ATSOG8?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 74FCT621ATSOG8 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 74FCT621ATSOG8?
74FCT621ATSOG8 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 74FCT621ATSOG8 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 74FCT621ATSOG8?
For technical support, including 74FCT621ATSOG8 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 74FCT621ATSOG8 requirements.
6.How does Aetrix verify that 74FCT621ATSOG8 is sourced from the original manufacturer or authorized distributors?
All 74FCT621ATSOG8 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 74FCT621ATSOG8 meets industry standards.
7.What is the process for return or replacement of 74FCT621ATSOG8?
All 74FCT621ATSOG8 units undergo pre-shipment inspection (PSI). If there is an issue with 74FCT621ATSOG8, 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 74FCT621ATSOG8 part is unused and in its original packaging.
Return procedure for 74FCT621ATSOG8:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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