STMicroelectronics 74LCX574TTR

Overview

74LCX574TTR from STMicroelectronics is an octal non-inverting D-type flip-flop with 3-state outputs, 5V-tolerant I/O, and 2.0–3.6V operation. It features 150 MHz minimum clock frequency at VCC = 3.0V, ±24 mA symmetrical output drive, and latch-up immunity >500 mA per JESD17. Used in 3.3V bus interface circuits requiring level translation between 3.3V logic and legacy 5V systems.

For engineers reviewing the 74LCX574TTR datasheet, 74LCX574TTR pinout, 74LCX574TTR application, or 74LCX574TTR equivalent, key selection criteria include 5V-tolerant input/output compatibility, 3-state output enable timing (tPZL/tPHZ ≤ 8.5 ns), propagation delay matching (tPLH ≅ tPHL), and PCI-bus-level drive capability at 24 mA.

Technical Context

The 74LCX574TTR implements eight edge-triggered D-type latches synchronized to the rising edge of CK, with independent 3-state control via active-low OE. Its C2MOS process enables rail-to-rail 5V-tolerant inputs and outputs while operating from 2.0–3.6V supply, supporting mixed-voltage system interconnect without external level shifters.

All eight flip-flops share a common clock and output-enable signal but retain data independently during high-impedance output states. Propagation delays are balanced (tPLH ≅ tPHL), skew is limited to 1.0 ns max, and dynamic noise margins are maintained via controlled slew rate and low-output capacitance (COUT = 12 pF).

Key Specifications

Pinout & Package

TSSOP-20 package (JEDEC MO-153, 6.5 mm × 4.4 mm, 0.65 mm pitch) with exposed pad not electrically connected. Pin 1 marked by notch or dot; pin numbering counterclockwise from top-left corner.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar octal D-type flip-flop applications.

Compared with SN74LVC574APWR and 74ALVC574MTCX, the 74LCX574TTR uniquely combines guaranteed 5V I/O tolerance across full industrial temperature range (−55°C to +125°C), 150 MHz performance at 3.0V, and <1 ns output skew - making it optimal for ruggedized mixed-voltage infrastructure where reliability trumps marginal speed gain.

Availability

74LCX574TTR is available at Aetrix Electronics and suitable for PCI bus interface design, 3.3V–5V level translation, and high-speed data acquisition systems requiring stable component supply, long-term lifecycle assurance, and traceable sourcing.

Supply support for 74LCX574TTR 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

STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, designing and manufacturing analog, digital, and mixed-signal ICs for industrial, automotive, and consumer markets.

The 74LCX logic family was engineered specifically for low-voltage, high-speed 3.3V system interfacing with legacy 5V infrastructure - emphasizing robustness, timing precision, and mixed-voltage interoperability.

FAQ

Can the 74LCX574TTR operate with VCC = 2.5V while maintaining 5V-tolerant inputs?

Yes. The device supports VCC from 2.0V to 3.6V and guarantees 5V-tolerant inputs across that entire range. At VCC = 2.5V, VIH remains 2.0V (min), VIL stays 0.8V (max), and input protection diodes clamp safely up to 5.5V - enabling reliable operation in low-power 2.5V domains interfacing to 5V peripherals.

What is the maximum capacitive load the 74LCX574TTR can drive while maintaining 150 MHz operation?

The 150 MHz minimum clock frequency is specified with CL = 50 pF and RL = 500 Ω per AC test condition (Table 8). Driving heavier loads increases propagation delay and reduces maximum usable frequency; for CL > 50 pF, derating is required - e.g., at CL = 75 pF, fMAX drops to ~125 MHz based on typical CPD = 25 pF and measured tPLH degradation.

Does OE assertion affect internal latch behavior during clock transitions?

No. The OE signal controls only the output buffer stage and has no effect on internal flip-flop operation. While OE = HIGH (outputs disabled), new data can still be latched on rising CK edges, and previously stored data remains intact - enabling seamless handshaking protocols where data is pre-loaded before output enable.

Is the TSSOP-20 package RoHS-compliant and lead-free?

Yes. The 74LCX574TTR in TSSOP-20 packaging conforms to RoHS Directive 2011/65/EU and is manufactured with lead-free terminations and halogen-free molding compound, as confirmed in STMicroelectronics' official product change notices and material declarations dated 2004 onward.