Texas Instruments CY74FCT273ATQC

Overview

CY74FCT273ATQC from Texas Instruments is an 8-bit edge-triggered D-type flip-flop register with common clock (CP) and master-reset (MR) inputs, 7.2 ns propagation delay (tPLH/tPHL), ±32 mA output drive capability, and Ioff partial-power-down support - used in synchronous data latching for industrial control bus interfaces.

For engineers reviewing the CY74FCT273ATQC datasheet, CY74FCT273ATQC pinout, CY74FCT273ATQC application, or CY74FCT273ATQC equivalent, key selection criteria include TTL-compatible input thresholds, 5 V supply operation, QSOP-20 package thermal performance (θJA = 68°C/W), and MR-synchronized asynchronous reset behavior.

Technical Context

This device implements eight independent D-type flip-flops sharing a single positive-edge-triggered clock and active-low master reset. All outputs update synchronously on the low-to-high CP transition, with setup time (tsu = 2 ns) and hold time (th = 1.5 ns) specified at VCC = 4.75–5.25 V.

It features edge-rate control circuitry to reduce switching noise, matched rise/fall times, and Ioff protection enabling safe back-drive during partial power-down. Input logic levels are fully TTL-compatible (VIH = 2 V min, VIL = 0.8 V max), and outputs drive to VOH = 2.4 V min (IOL = 64 mA) and VOL = 0.55 V max.

Key Specifications

Pinout & Package

Package: 20-pin QSOP (DBQ), 0.154" body width, 0.025" lead pitch, θJA = 68°C/W, RoHS-compliant green finish (CU NIPDAU).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 8-bit D-type register applications.

Compared with SN74FCT273QDR, CY74FCT273ATQC offers identical electrical and thermal behavior with full documentation traceability to TI's FCT family; versus 74ACT273SCX, it delivers superior noise immunity, higher drive strength, and essential Ioff protection for modern embedded power management.

Availability

CY74FCT273ATQC is available at Aetrix Electronics and suitable for industrial PLC I/O expansion, legacy bus interface buffering, and motor control logic sequencing requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for CY74FCT273ATQC 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 industrial-grade component development.

CY74FCT273ATQC belongs to the TI FCT logic family, engineered for high-noise-immunity 5 V TTL-compatible digital interfacing in industrial automation, test equipment, and legacy system upgrades.

FAQ

What is the maximum clock frequency supported by CY74FCT273ATQC?

CY74FCT273ATQC has a maximum propagation delay of 7.2 ns (tPLH/tPHL), yielding a theoretical maximum toggle rate of ~70 MHz under ideal conditions. Real-world system timing must account for setup (2 ns) and hold (1.5 ns) margins, limiting practical synchronous operation to ≤50 MHz in noise-prone environments. The device does not specify a guaranteed maximum clock frequency - design validation requires worst-case timing analysis using the full parameter table.

Does CY74FCT273ATQC support partial power-down, and how is it implemented?

Yes, CY74FCT273ATQC supports partial power-down via its Ioff circuitry. When VCC = 0 V, the outputs are actively disabled with leakage current limited to ±1 µA even if external voltages up to 4.5 V are applied to pins. This prevents damaging back-current flow during hot-swap or modular power sequencing - a key requirement in programmable logic controllers and field-replaceable I/O modules where CY74FCT273ATQC is commonly deployed.

What is the pin compatibility status between CY74FCT273ATQC and CY74FCT273TQCT?

CY74FCT273ATQC and CY74FCT273TQCT share identical 20-pin QSOP (DBQ) packaging, pinout, and function mapping. Both devices use the same CP, MR, D0–D7, Q0–Q7, VCC, and GND assignments. However, they differ in speed grade (7.2 ns vs. 13 ns) and output drive (64/32 mA vs. 32/12 mA), so substitution requires verification of timing and fanout requirements in the target application.

Can CY74FCT273ATQC be used with 3.3 V logic systems?

No, CY74FCT273ATQC is strictly a 5 V device with recommended operating voltage of 4.75–5.25 V. Its TTL-compatible inputs require VIH ≥ 2 V and VIL ≤ 0.8 V, but it lacks 3.3 V supply support or level-shifting capability. Driving its inputs from 3.3 V logic may result in marginal VIH margin (2 V threshold vs. 3.3 V output), and powering it at 3.3 V violates absolute maximum ratings. For 3.3 V systems, consider TI's 74LVC273 or similar LVCMOS-compatible registers instead of CY74FCT273ATQC.

How does the master reset (MR) pin behave during power-up sequences?

The MR pin on CY74FCT273ATQC is active-low and asynchronous - asserting MR low forces all Q outputs immediately to logic low, independent of CP state or timing. During power-up, if MR is held low until VCC stabilizes above 4.75 V and then released, the register enters a known zero state before first clock edge. TI recommends tying MR to a power-on reset circuit or microcontroller GPIO to guarantee deterministic initialization, especially in safety-critical industrial controls where CY74FCT273ATQC often serves as a safety latch.