Renesas 74FCT245ATPYG

Overview

74FCT245ATPYG from Renesas Electronics is a fast CMOS octal bidirectional transceiver in 20-pin TSSOP package, operating at 5.0V ±5%, with industrial temperature range (–40°C to +85°C), 4.1 ns max propagation delay (A↔B), and ±15 mA/64 mA output drive (IOH/IOL). It enables asynchronous bus isolation in backplane or motherboard interconnects.

For engineers reviewing the 74FCT245ATPYG datasheet, 74FCT245ATPYG pinout, 74FCT245ATPYG application, or 74FCT245ATPYG equivalent, key selection criteria include direction control (T/R), 3-state enable (OE active-low), high-drive capability for stub-loaded buses, and TTL-compatible I/O levels with low leakage (≤1 µA).

Technical Context

The 74FCT245ATPYG implements an asynchronous bidirectional data path between two 8-bit buses using dual-rail CMOS logic. Direction is controlled by the T/R input (active-high for A→B, active-low for B→A), while OE independently places both A and B ports into high-impedance state when asserted high.

It meets JEDEC Std 18 and MIL-STD-883 Class B requirements for military-grade reliability, supports live insertion via power-off disable outputs, and delivers rail-to-rail TTL-compatible output swing (VOH = 3.3 V typ., VOL = 0.3 V typ.) with CMOS power efficiency (ICC ≤ 1 mA quiescent).

Key Specifications

Pinout & Package

74FCT245ATPYG is housed in a 20-pin Thin Shrink Small Outline Package (TSSOP), designated PYG20 per Renesas ordering nomenclature. Pin spacing is 0.65 mm, body width 4.4 mm, and total length 6.5 mm - optimized for high-density PCB layouts with automated assembly compatibility.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar bidirectional transceiver applications.

Compared with SN74F245N and 74LVC245APW, the 74FCT245ATPYG uniquely combines 5V TTL compatibility, industrial temperature rating, live-insertion support, and sub-5 ns timing - making it the sole option for robust, drop-in-replacement upgrades in legacy 5V backplane architectures.

Availability

74FCT245ATPYG is available at Aetrix Electronics and suitable for backplane bus isolation, industrial PLC I/O expansion, legacy system interfacing, and test equipment signal routing requiring stable component supply across extended lifecycle programs.

Supply support for 74FCT245ATPYG 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

Renesas Electronics Corporation is a global semiconductor leader delivering microcontrollers, analog, power, and SoC solutions for automotive, industrial, and infrastructure markets.

The 74FCT245ATPYG belongs to Renesas' legacy IDT fast CMOS logic family, designed specifically for high-reliability, 5V bus bridging in industrial control, military computing, and telecom infrastructure where timing precision and ruggedness are critical.

FAQ

What is the maximum operating frequency supported by the 74FCT245ATPYG?

The 74FCT245ATPYG does not specify a maximum clock frequency because it is an asynchronous transceiver - its usable data rate depends on propagation delay and system timing margins. With 4.1 ns max tPLH/tPHL and typical bus loading, it reliably supports bidirectional data transfers up to 200+ Mbps in point-to-point configurations. The 74FCT245ATPYG's performance is validated under JEDEC Std 18 conditions with CL = 50 pF and RL = 500 Ω.

Does the 74FCT245ATPYG support live insertion, and how is this implemented?

Yes, the 74FCT245ATPYG supports live insertion through power-off disable outputs: when VCC = 0 V, all A and B port outputs enter high-impedance state regardless of OE or T/R state. This prevents bus contention during hot-swap events in modular systems. The 74FCT245ATPYG achieves this via internal circuitry that overrides output drivers during undervoltage conditions - a feature confirmed in the Absolute Maximum Ratings and Functional Description sections of the Renesas datasheet.

What are the voltage thresholds for VIH and VIL on the 74FCT245ATPYG control inputs?

The 74FCT245ATPYG specifies VIH ≥ 2.0 V (guaranteed logic HIGH) and VIL ≤ 0.8 V (guaranteed logic LOW) across the full industrial temperature range. These thresholds ensure reliable interfacing with standard TTL and LVTTL sources. The 74FCT245ATPYG also provides 200 mV of input hysteresis to reject noise on OE and T/R lines - a critical feature for stable operation in electrically noisy industrial environments.

Can the 74FCT245ATPYG be used in a 3.3V system?

No - the 74FCT245ATPYG is strictly a 5V device: its absolute maximum VCC is 5.5 V, and DC electrical characteristics (VIH/VIL, VOH/VOL, drive strength) are specified only at VCC = 5.0 V ±5%. Operating the 74FCT245ATPYG at 3.3V will result in undefined logic levels, insufficient output drive, and potential functional failure. For 3.3V systems, Renesas recommends the 74LVC245 series instead.

How does the 74FCT245ATPYG differ from the 74FCT245CTPYG variant?

The 74FCT245ATPYG and 74FCT245CTPYG share identical pinout, package, and functionality but differ in timing performance: the 'A' grade has 4.1 ns max propagation delay (vs. 4.6 ns for 'C'), 5.8 ns max tPZL/tPHZ (vs. 6.2 ns), and tighter output enable/disable specs. Both operate over –40°C to +85°C, but the 'A' grade offers improved timing margins for high-speed bus designs - the 74FCT245ATPYG is preferred when sub-5 ns latency is required.