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onsemi 74ACT16646SSCX
- Part No.:
- 74ACT16646SSCX
- Manufacturer:
- onsemi
- Package:
- 56-BSSOP (0.295", 7.50mm Width)
- Datasheet:
-
74ACT16646SSCX.pdf
- Description:
- IC TXRX NON-INVERT 5.5V 56SSOP
- Quantity:
- Payment:
- Shipping:
Inventory:3,096
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Product details
Overview
74ACT16646SSCX from Fairchild Semiconductor is a 16-bit bidirectional registered transceiver with 3-state outputs, designed for high-speed bus interface and data multiplexing between A and B buses in TTL-compatible systems. It supports real-time transparent transfer and stored-mode register-to-bus operation, features independent A/B bus registers, separate byte-level control, and ±24 mA output drive at 4.5–5.5 V supply.
For engineers reviewing the 74ACT16646SSCX datasheet, pinout, applications, or equivalent options, key selection criteria include direction-controlled bidirectional data flow, dual-clock register loading (CPAB/CPBA), 3-state enable (G), DIR-controlled transfer mode, and SSOP-56 package compatibility with JEDEC MO-118.
Technical Context
The 74ACT16646SSCX implements two independent 8-bit register banks (A0–A7 and B0–B7), each with dedicated clock inputs (CPABn, CPBAn) that trigger data capture on LOW-to-HIGH transitions. Direction control is managed per byte via DIR1/DIR2, while output enable is controlled by active-low G1/G2 signals.
It operates exclusively in 5 V TTL-compatible logic domains (VCC = 4.5–5.5 V, VIH = 2.0 V min, VOL = 0.44 V max at 24 mA), with propagation delays as low as 3.2 ns (tPLH, bus-to-bus) and setup/hold times of 3.0 ns / 1.5 ns - optimized for synchronous bus arbitration and latch-based data staging in industrial control backplanes.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Logic Family | ACT (Advanced CMOS TTL-compatible), enabling direct interface with 74LS/74F without level shifters |
| Bus Width | 16-bit bidirectional (two independent 8-bit sections), supporting split-byte control in memory-mapped I/O |
| Output Drive | ±24 mA at VCC = 5.5 V, sufficient to drive 10 LSTTL loads or terminate short PCB traces |
| Propagation Delay | 3.2–10.4 ns (CL = 50 pF), enabling ≤100 MHz burst data transfers in synchronous bus architectures |
| Operating Temperature | −40°C to +85°C, qualified for industrial-grade embedded controller and test equipment use |
| Supply Voltage | 4.5 V to 5.5 V, rejecting up to ±10% rail variation without functional degradation |
| Input Thresholds | VIH = 2.0 V min, VIL = 0.8 V max, ensuring noise margin >0.4 V under worst-case VCC and temperature |
Pinout & Package
74ACT16646SSCX is housed in a 56-lead Shrink Small Outline Package (SSOP), JEDEC MO-118 compliant, 0.300" wide, with 0.025" pitch and exposed thermal pad not present - suitable for reflow assembly and automated optical inspection.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| G1, G2 | Output Enable (active-low) | Disables all A/B bus outputs simultaneously; used for bus contention avoidance during multi-master arbitration |
| DIR1, DIR2 | Data Direction Control | Selects A→B (DIR=H) or B→A (DIR=L) real-time transfer per 8-bit section |
| CPAB1–2, CPBA1–2 | Register Clock Inputs | Load data from A/B bus into respective registers on rising edge; enables synchronized snapshot capture |
| A0–A7, B0–B7 | Bidirectional Data I/O | Shared pins for real-time transfer and register readback; no internal series termination |
| VCC, GND | Power Supply | Dual VCC/GND pairs (pins 1/28, 29/56) reduce switching noise and improve PSRR in high-speed operation |
Key Features
| Feature | Design Value |
|---|---|
| Independent A/B Bus Registers | Enables concurrent data staging: e.g., A bus captures sensor data while B bus transmits prior frame to host MCU |
| Multiplexed Real-Time + Stored Transfer | Eliminates need for external latches - same device handles both streaming and buffered modes |
| Separate Byte-Level Control | Permits 8-bit sub-bus isolation (e.g., control/status vs. data lanes) without full 16-bit gate delay penalty |
| TTL-Compatible Inputs | Accepts standard 74LS/74F logic levels directly; no pull-up resistors or level translators required |
| 3-State Output Enable | Allows connection to shared backplane or daisy-chained bus topology with deterministic tri-state recovery |
Applications
| Industrial PLC Backplane Interface | Legacy ISA Bus Extender |
|---|---|
Use Scenario: Interfacing microcontroller peripherals (ADC, DAC, GPIO) to a 16-bit parallel backplane in programmable logic controllers. IC Role / Device Role / Timing Role: Registered transceiver providing synchronized data capture and bus isolation between CPU and I/O modules. Use Value: Eliminates external octal latches; DIR and G controls allow dynamic bus ownership handoff during interrupt-driven I/O cycles. | Use Scenario: Extending legacy ISA bus signals to modern FPGA-based coprocessor cards requiring 5 V tolerant, registered data paths. IC Role / Device Role / Timing Role: Bidirectional registered buffer matching ISA timing requirements (tS = 3.0 ns, tW = 4.0 ns). Use Value: Meets ISA specification hold/setup margins while supporting stored-mode buffering for burst DMA transfers. |
| Test Equipment Digital Pattern Generator | Automated Test Fixture Controller |
Use Scenario: Generating precise, glitch-free 16-bit stimulus patterns with synchronized register load for repeatability across test cycles. IC Role / Device Role / Timing Role: Register-based pattern source with CPAB/CPBA-triggered deterministic state capture. Use Value: Enables repeatable waveform generation without external clock domain crossing logic or FIFOs. | Use Scenario: Controlling multiple DUT interfaces (relays, sensors, power rails) via a shared 16-bit control bus with isolated status feedback. IC Role / Device Role / Timing Role: Dual-role transceiver handling both command output (A→B) and status input (B→A) on same physical lines. Use Value: Reduces connector pin count by 50% versus unidirectional buffers; DIR toggling enables full-duplex control over half-duplex wiring. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar registered transceiver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 74ACT16245SSCX | No internal registers; only real-time bidirectional transfer; lacks CPAB/CPBA clock inputs and storage capability | Suitable for simple bus drivers but cannot replace register-based data staging or snapshot capture functions | Select when only level-shifting and direction control are needed - not for stored-mode operation |
| SN74LVC16646APAG | 3.3 V only (1.65–3.6 V), lower drive (±24 mA @ 3.3 V), different pinout (TSSOP-56, non-JEDEC MO-118) | Requires level translation for 5 V systems; incompatible pin mapping prevents drop-in replacement | Choose for 3.3 V mixed-signal systems where voltage scaling and lower power outweigh 5 V compatibility |
Compared with 74ACT16646SSCX, the 74ACT16245SSCX omits register functionality entirely - limiting it to basic bus driving - while the SN74LVC16646APAG offers identical register architecture but mandates 3.3 V operation and requires PCB redesign due to pinout mismatch.
Availability
74ACT16646SSCX is available at Aetrix Electronics and suitable for industrial PLC backplanes, legacy ISA bus extenders, and automated test fixture controllers requiring stable component supply, long-term obsolescence management, and guaranteed traceable sourcing.
Supply support for 74ACT16646SSCX 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
Fairchild Semiconductor was a U.S.-based semiconductor company specializing in analog and mixed-signal ICs, power management, and logic devices before its acquisition by ON Semiconductor in 2016.
The 74ACT16646 belongs to Fairchild's ACT logic family - engineered for high-speed, 5 V TTL-compatible bus interfacing in industrial control, instrumentation, and legacy computing systems.
FAQ
What is the function of CPAB and CPBA inputs on the 74ACT16646SSCX?
The CPAB and CPBA inputs on the 74ACT16646SSCX are clock inputs that load data from the A or B bus into the corresponding internal registers on a LOW-to-HIGH transition. CPABn clocks data from the A bus into the B-side register, while CPBAn clocks data from the B bus into the A-side register - enabling synchronized, edge-triggered data capture without external flip-flops. This behavior is confirmed in the Function Table and Logic Diagram of the official Fairchild DS500345 datasheet.
Does the 74ACT16646SSCX support 3.3 V operation?
No, the 74ACT16646SSCX is specified only for 4.5 V to 5.5 V operation per its Recommended Operating Conditions. Its input thresholds (VIH = 2.0 V min) and output drive characteristics (VOH ≥ 4.4 V at 5 V) are optimized for 5 V TTL compatibility. Attempting 3.3 V supply violates datasheet limits and risks undefined logic states, reduced noise margin, and failure to meet AC timing specifications.
What package type does the 74ACT16646SSCX use?
74ACT16646SSCX uses a 56-lead Shrink Small Outline Package (SSOP) with JEDEC MO-118 compliance, 0.300" body width, and 0.025" lead pitch. The "SSC" in the part number explicitly denotes this SSOP variant, distinct from the TSSOP version (74ACT16646MTD). Package dimensions and land pattern requirements are documented in Fairchild's DS500345 datasheet, page 5.
How does the 74ACT16646SSCX differ from the standard 74ACT646?
The 74ACT16646SSCX is the 16-bit extension of the 8-bit 74ACT646, retaining identical functional architecture (dual-register, DIR/G/CP control) but doubling the bus width and splitting control into two independent 8-bit sections (DIR1/G1/CPAB1/CPBA1 and DIR2/G2/CPAB2/CPBA2). This allows byte-granular direction and enable control - critical for partial bus access in memory-mapped I/O systems.
Is the 74ACT16646SSCX RoHS compliant?
The 74ACT16646SSCX was manufactured prior to RoHS enforcement (pre-2006) and is not RoHS compliant per EU Directive 2011/65/EU. It contains lead in solder and die attach materials. For RoHS-compliant alternatives, consider functionally similar devices such as SN74LVC16646A (3.3 V) or contact Aetrix Electronics for legacy-compliant sourcing options with full material declarations.
74ACT16646SSCX Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- 74ACT
- Package/Case:
- 56-BSSOP (0.295", 7.50mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Logic Type:
- Transceiver, Non-Inverting
- Number of Elements:
- 2
- Number of Bits per Element:
- 8
- Input Type:
- -
- Output Type:
- 3-State
- Current - Output High, Low:
- 24mA, 24mA
- Voltage - Supply:
- 4.5V ~ 5.5V
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 56-SSOP
74ACT16646SSCX FAQ
1.How can I place an order for 74ACT16646SSCX through Aetrix?
Please submit a Request for Quotation (RFQ) for 74ACT16646SSCX 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 74ACT16646SSCX reliable?
The price and inventory of 74ACT16646SSCX are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 74ACT16646SSCX is usually 5 days.
3.What payment methods are accepted for 74ACT16646SSCX?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 74ACT16646SSCX transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 74ACT16646SSCX?
74ACT16646SSCX orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 74ACT16646SSCX 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 74ACT16646SSCX?
For technical support, including 74ACT16646SSCX datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 74ACT16646SSCX requirements.
6.How does Aetrix verify that 74ACT16646SSCX is sourced from the original manufacturer or authorized distributors?
All 74ACT16646SSCX 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 74ACT16646SSCX meets industry standards.
7.What is the process for return or replacement of 74ACT16646SSCX?
All 74ACT16646SSCX units undergo pre-shipment inspection (PSI). If there is an issue with 74ACT16646SSCX, 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 74ACT16646SSCX part is unused and in its original packaging.
Return procedure for 74ACT16646SSCX:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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