Texas Instruments CY74FCT377CTQCT

Overview

CY74FCT377CTQCT from Texas Instruments is an 8-bit edge-triggered D-type register with clock enable, designed for synchronous data latching in TTL-compatible digital systems. It features 64-mA sink / 32-mA source drive strength, 5.2-ns propagation delay (tPLH/tPHL), and Ioff support for partial-power-down operation. Used in address/data synchronization, bus interface buffering, and control logic sequencing.

For engineers reviewing the CY74FCT377CTQCT datasheet, CY74FCT377CTQCT pinout, CY74FCT377CTQCT application, or CY74FCT377CTQCT equivalent, key selection criteria include its QSOP-20 package, 4.75–5.25-V supply range, edge-rate controlled outputs for noise immunity, and compatibility with FCT-family timing and drive specifications.

Technical Context

This device implements eight independent D-type flip-flops sharing a common buffered clock (CP) and clock-enable (CE) input. All outputs update synchronously on the low-to-high CP transition when CE is low, with setup/hold times of 2 ns (tsu) and 1.5 ns (th) respectively.

It integrates edge-rate control circuitry to reduce switching noise, matched rise/fall times for clean signal edges, and Ioff protection enabling safe back-drive isolation during partial power-down. Fully compatible with TTL input thresholds (VIH = 2 V, VIL = 0.8 V) and 5-V CMOS output levels.

Key Specifications

Pinout & Package

Package: QSOP-20 (DBQ), 0.150-inch body width, 0.65-mm lead pitch, RoHS-compliant NiPdAu finish, MSL Level-2-260°C-1 year.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 8-bit registered latch applications.

Compared with CY74FCT377CTQCT, SN74FCT377TQCT offers relaxed supply tolerance but sacrifices speed and drive strength, while 74ACT377SCX delivers faster propagation at the cost of missing Ioff and edge-rate control - making CY74FCT377CTQCT the optimal choice for noise-sensitive, partial-power-down-capable 5-V systems.

Availability

CY74FCT377CTQCT is available at Aetrix Electronics and suitable for industrial PLC I/O expansion, legacy bus interface buffering, and automotive body control module designs requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for CY74FCT377CTQCT 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 digital interface components.

CY74FCT377CTQCT belongs to TI's FCT logic family - engineered for noise-immune, TTL-compatible 5-V digital interfacing in industrial, automotive, and communications infrastructure applications.

FAQ

What is the maximum clock frequency supported by CY74FCT377CTQCT?

CY74FCT377CTQCT does not specify a maximum clock frequency in its datasheet; instead, it defines minimum pulse width (tw = 6 ns) and setup/hold timing (tsu = 2 ns, th = 1.5 ns). Based on these values, the practical maximum toggle rate is approximately 83 MHz under ideal conditions. The CY74FCT377CTQCT is optimized for synchronous latching rather than continuous high-frequency operation, and its 5.2-ns propagation delay ensures reliable timing closure in systems with ≤25-MHz clock domains.

Does CY74FCT377CTQCT support 3.3-V operation?

No, CY74FCT377CTQCT is strictly a 5-V device with recommended operating supply range of 4.75 V to 5.25 V. Its input thresholds (VIH = 2.0 V, VIL = 0.8 V) and output VOH/VOL specs are defined only within this range. Applying 3.3 V to VCC will result in undefined logic behavior, insufficient noise margin, and potential failure to meet timing or drive specifications. For 3.3-V systems, consider TI's LVC or AUC logic families instead of CY74FCT377CTQCT.

How does the Ioff feature function in CY74FCT377CTQCT during partial power-down?

In CY74FCT377CTQCT, the Ioff circuitry actively disables all outputs when VCC = 0 V, limiting leakage current to ±1 µA even if input or output pins are driven externally at up to 4.5 V. This prevents damaging back-current flow through the device during hot-swap or multi-rail power sequencing. The feature requires no external control - it activates automatically upon VCC removal - and is fully characterized per JESD78, making CY74FCT377CTQCT suitable for systems requiring safe power gating.

Can CY74FCT377CTQCT be used as a replacement for SN74FCT377TQCT?

CY74FCT377CTQCT is pin-compatible and functionally identical to SN74FCT377TQCT but offers superior performance: 5.2-ns propagation delay vs. 7.2 ns, 64-mA sink drive vs. 32 mA, and tighter VCC tolerance (4.75–5.25 V vs. 4.5–5.5 V). However, SN74FCT377TQCT supports wider voltage margins and may be preferred in less-regulated 5-V rails. Both share identical QSOP-20 footprint and logic behavior, so CY74FCT377CTQCT can serve as a performance-upgraded drop-in replacement where timing and drive strength are critical.

What PCB layout considerations are critical for CY74FCT377CTQCT signal integrity?

For optimal performance, place a 0.1-µF ceramic decoupling capacitor within 10 mm of CY74FCT377CTQCT's VCC pin (Pin 20), route GND (Pin 10) with low-inductance copper pour, and avoid routing sensitive signals (CP, CE) parallel to noisy traces. Use controlled-impedance routing only if trace length exceeds 10 cm; otherwise, keep CP/CE traces short and shielded. The edge-rate control in CY74FCT377CTQCT reduces need for series termination, but series resistors (22–33 Ω) on outputs are recommended for long traces or high-fanout loads.