Texas Instruments CY74FCT823CTSOC

Overview

CY74FCT823CTSOC from Texas Instruments is a 9-bit bus-interface register with 3-state outputs, positive-edge-triggered D-type flip-flops, buffered clock-enable (EN) and asynchronous clear (CLR), and TTL-compatible I/O logic levels. It delivers 64 mA sink / 32 mA source drive, 6 ns propagation delay (tPLH/tPHL at CL = 50 pF), and supports partial-power-down via Ioff. It is used in high-performance microprogrammed systems for parity bus interfacing and high-current output port applications.

For engineers reviewing the CY74FCT823CTSOC datasheet, CY74FCT823CTSOC pinout, CY74FCT823CTSOC application, or CY74FCT823CTSOC equivalent, key selection criteria include its 9-bit width, 3-state output control timing (tPZL/tPHZ = 7 ns), Ioff-enabled power-down safety, edge-rate-controlled noise immunity, and SOIC-24 package compatibility with legacy FCT-family designs.

Technical Context

This device implements nine independent D-type flip-flops synchronized to the rising edge of CP, with shared EN (clock enable) and CLR (asynchronous clear) inputs. All outputs are 3-state controlled by OE, enabling bus sharing without external buffers.

It features edge-rate control circuitry to reduce switching noise, matched rise/fall times for clean signal integrity, and full TTL-level compatibility on both inputs and outputs - including VIH = 2 V min and VOL = 0.55 V max at IOL = 64 mA. The Ioff specification (±1 µA at VCC = 0 V) ensures backflow protection during partial power-down.

Key Specifications

Pinout & Package

Package: SOIC-24 (DW), 7.5 mm × 15.4 mm body, 1.27 mm pitch, RoHS-compliant NIPDAU finish, MSL Level-1.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 9-bit bus-interface register applications.

Compared with CY74FCT823ATSOC, the CY74FCT823CTSOC provides 40% faster propagation delay for tighter timing budgets; compared with SN74FCT823CTSO, it offers identical performance with updated part numbering and packaging compliance (RoHS, MSL-1).

Availability

CY74FCT823CTSOC is available at Aetrix Electronics and suitable for industrial control systems, legacy bus expansion modules, and 5 V TTL interface bridges requiring stable component supply, long-term lifecycle support, and RoHS-compliant SOIC packaging.

Supply support for CY74FCT823CTSOC 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 delivering analog, embedded processing, and logic solutions for industrial, automotive, and communications markets.

The CY74FCT823CTSOC belongs to TI's FCT logic family, engineered for high-speed, low-noise 5 V bus interfacing in systems requiring TTL compatibility, robust ESD performance, and partial-power-down safety.

FAQ

What is the maximum clock frequency supported by CY74FCT823CTSOC?

The CY74FCT823CTSOC does not specify a maximum clock frequency in its datasheet; instead, it guarantees 6 ns propagation delay (tPLH/tPHL) and 3 ns setup/hold times (tsu/th) at CL = 50 pF. Based on these timing parameters, reliable operation up to approximately 83 MHz is achievable in well-terminated 5 V TTL buses. The actual usable frequency depends on board layout, load capacitance, and signal integrity - the CY74FCT823CTSOC itself imposes no internal frequency limit beyond its AC specifications.

Does CY74FCT823CTSOC support hot-swap or live-insertion?

Yes, the CY74FCT823CTSOC supports partial-power-down operation via its Ioff feature: when VCC = 0 V, Ioff is limited to ±1 µA even with input/output voltages up to 4.5 V. This prevents damaging current backflow during hot-swap events. However, proper system-level sequencing - including controlled OE assertion before power removal - is required. The CY74FCT823CTSOC alone satisfies the IC-level requirement for hot-swap safety but must be integrated with appropriate board-level protection.

Can CY74FCT823CTSOC drive a 100 pF bus load reliably?

Yes, the CY74FCT823CTSOC is characterized for CL = 50 pF and CL = 300 pF loads. At CL = 100 pF, propagation delay increases to ~8.5 ns (interpolated from tPLH/tPHL = 6 ns @ 50 pF and 12.5 ns @ 300 pF), remaining within functional timing margins for most 5 V systems. Its 64 mA sink capability also ensures fast edge rates into 100 pF, and edge-rate control minimizes ringing. For optimal signal integrity, maintain controlled impedance and minimize stub lengths when driving 100 pF.

Is CY74FCT823CTSOC pin-compatible with CY74FCT823BTPC?

No, CY74FCT823CTSOC (SOIC-24) is not pin-compatible with CY74FCT823BTPC (DIP-24). While both share identical logic functionality and signal naming (D0–D8, Y0–Y8, CP, EN, CLR, OE, VCC, GND), their physical packages differ: SOIC-24 has 24 leads in a 7.5 mm × 15.4 mm gull-wing configuration, whereas DIP-24 uses a 0.6-inch wide through-hole layout with 0.1-inch lead spacing. Board redesign is required for substitution; however, the CY74FCT823CTSOC is pin-compatible with CY74FCT823ATSOC and CY74FCT823CTSOCT.

What is the purpose of the "reduced VOH" specification for CY74FCT823CTSOC?

The reduced VOH (typical 3.3 V, min 2.4 V at IOH = –32 mA) in the CY74FCT823CTSOC lowers high-level output voltage versus standard 5 V TTL, improving noise margin when interfacing with 3.3 V logic while retaining full compatibility with 5 V TTL inputs (VIH ≥ 2 V). This design reduces overshoot and EMI on heavily loaded buses and eases integration into mixed-voltage systems - a key differentiator from earlier FCT variants with higher VOH. The CY74FCT823CTSOC achieves this without external components or configuration.