onsemi 74LVT2245MTC

Overview

74LVT2245MTC from Fairchild Semiconductor is a low-voltage octal bidirectional transceiver with 3-STATE inputs/outputs and integrated 25Ω series resistors on B-port outputs, designed for 3.3V bus interfacing between TTL (5V) and LVT logic domains. It supports bidirectional data flow controlled by T/R and OE pins, delivers ±12mA/±64mA drive on B/A ports respectively, and operates across –40°C to +85°C.

For engineers reviewing the 74LVT2245MTC datasheet, pinout, applications, or equivalent options, key selection criteria include its 25Ω B-port series termination for signal integrity, bushold-free operation (unlike LVTH variant), 3.3V supply compatibility with 5V-tolerant I/O, and TSSOP-20 packaging for high-density PCB layouts.

Technical Context

The 74LVT2245MTC implements eight non-inverting bidirectional buffers with independent 3-STATE control via OE and directional control via T/R. Its BiCMOS fabrication enables ABT-class speed (tPLH/tPHL ≤ 4.4ns at 3.3V) while maintaining low power dissipation (ICCL = 5mA max).

Unlike the bushold-equipped 74LVTH2245MTC, this device requires external pull-up/pull-down on unused inputs. The 25Ω series resistor on each B-port output reduces overshoot/undershoot in high-speed bus environments without requiring discrete termination components.

Key Specifications

Pinout & Package

74LVT2245MTC is housed in a 20-lead Thin Shrink Small Outline Package (TSSOP), JEDEC MO-153 compliant, 4.4mm wide, with 0.65mm lead pitch and exposed pad not present. This package supports automated assembly and provides thermal and electrical performance suitable for space-constrained industrial PCBs.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 74LVTH2245MTC and SN74LVC2245APW, the 74LVT2245MTC uniquely combines 5V-tolerant I/O, integrated 25Ω B-port termination, and bushold-free operation-making it optimal for industrial backplanes where signal integrity, voltage translation, and layout simplicity are jointly critical.

Availability

74LVT2245MTC is available at Aetrix Electronics and suitable for industrial backplane interfaces, memory expansion subsystems, and modular PLC I/O carriers requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.

Supply support for 74LVT2245MTC 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

Fairchild Semiconductor was a U.S.-based semiconductor company specializing in power management, signal conditioning, and interface solutions before its acquisition by ON Semiconductor in 2016. Its LVT logic family set industry benchmarks for speed-power tradeoffs in 3.3V systems.

The 74LVT2245MTC belongs to Fairchild's Low-Voltage Transceiver (LVT) product line, engineered specifically for high-speed, mixed-voltage bus bridging in industrial control, telecom infrastructure, and embedded computing platforms.

FAQ

What is the maximum data rate supported by the 74LVT2245MTC?

The 74LVT2245MTC does not specify a maximum data rate in MHz, but its propagation delay (tPLH/tPHL ≤ 4.4ns at 3.3V) and output skew (<1.0ns) support reliable operation up to ~100MHz in well-terminated point-to-point or lightly loaded multidrop bus configurations. Actual achievable rate depends on trace length, load capacitance, and termination strategy - the integrated 25Ω B-port resistors aid stability at these speeds.

Does the 74LVT2245MTC have bushold functionality on its inputs?

No, the 74LVT2245MTC does not include bushold inputs. That feature is exclusive to the 74LVTH2245MTC variant. Unused inputs on the 74LVT2245MTC must be externally terminated with pull-up or pull-down resistors to prevent floating states and potential increased ICC or noise susceptibility. This design choice reduces input leakage current (±1µA vs. ±75µA in bushold mode) and simplifies biasing in known-state systems.

Can the 74LVT2245MTC safely interface a 3.3V microcontroller with a 5V peripheral bus?

Yes, the 74LVT2245MTC is explicitly designed for this use case: its I/O pins tolerate up to 5.5V input voltage while operating from a 2.7–3.6V VCC supply. When the microcontroller drives the A port, the 74LVT2245MTC translates logic levels to 5V-compatible thresholds (VIH = 2.0V, VIL = 0.8V) and drives the 5V bus via B port with 25Ω series resistance to limit edge rates and suppress ringing - making the 74LVT2245MTC ideal for such mixed-voltage interconnects.

What is the purpose of the 25Ω series resistors on the B port outputs of the 74LVT2245MTC?

The 25Ω series resistors integrated into each B port output of the 74LVT2245MTC serve to dampen signal reflections caused by impedance mismatches on transmission lines or unterminated bus stubs. They reduce overshoot and undershoot during fast edge transitions, improving signal integrity without requiring discrete surface-mount resistors. This feature is especially valuable in compact industrial PCBs where layout space is constrained and consistent termination across eight lines would otherwise demand eight additional components and routing effort.

Is the 74LVT2245MTC pin-compatible with other members of the 74LVT2245 family?

Yes, the 74LVT2245MTC shares identical pinout and function with all 74LVT2245 variants (e.g., 74LVT2245WM, 74LVT2245SJ) regardless of package type - SOIC, SOP, or TSSOP. All use the same 20-pin configuration with OE, T/R, A0–A7, B0–B7, VCC, and GND assigned identically. Mechanical differences (package width, lead pitch, thermal pad presence) do not affect electrical connectivity or PCB footprint compatibility within their respective land patterns.