onsemi MC74VHC245DTG

Overview

MC74VHC245DTG from onsemi is an advanced high-speed CMOS octal bus transceiver in TSSOP-20 package, supporting bidirectional data flow between 3.3 V and 5.0 V buses with direction control (DIR) and 3-state output enable (OE). It delivers 4.0 ns typical propagation delay at 5.0 V, ±25 mA output drive, and operates across −40°C to +85°C for industrial bus interfacing applications.

For engineers reviewing the MC74VHC245DTG datasheet, pinout, applications, or equivalent options, this page provides verified functional identity, validated TSSOP-20 pin mapping, confirmed voltage translation capability (3.3 V ↔ 5.0 V), real-world isolation behavior under OE control, and two manufacturer-validated alternative parts for system-level compatibility assessment.

Technical Context

The MC74VHC245DTG implements dual-bus bidirectional buffering using silicon gate CMOS technology with independent DIR and OE control logic. Its input structure tolerates up to 5.5 V, enabling safe interfacing of 5 V systems to 3 V logic domains without external level-shifting circuitry.

It features balanced propagation delays (tPLH ≈ tPHL), low dynamic noise (VOLP ≤ 1.2 V), and power-down protection that maintains output integrity when VCC = 0 V - critical for hot-swap and battery-backup scenarios. All inputs include ESD protection exceeding 2000 V HBM.

Key Specifications

Pinout & Package

TSSOP-20 (Case 948E), 0.65 mm pitch, 6.5 mm × 4.4 mm footprint, 1.2 mm max height - optimized for space-constrained PCB layouts while maintaining thermal performance (θJA = 150°C/W).

Key Features

Applications

Equivalent & Alternatives

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

Compared with MC74VHC245DTG, MC74VHCT245ADTG offers TTL input compatibility at identical footprint and timing, while SN74LVC245APW trades voltage flexibility for lower latency in single-supply 3.3 V systems - selection depends on input source type and system voltage architecture.

Availability

MC74VHC245DTG is available at Aetrix Electronics and suitable for industrial PLC backplanes, embedded microcontroller expansion buses, automotive diagnostic modules, and test equipment digital I/O adapters requiring stable component supply and long-term manufacturability.

Supply support for MC74VHC245DTG 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

onsemi (formerly ON Semiconductor) is a global semiconductor supplier specializing in energy-efficient power management, analog, sensor, and logic solutions for automotive, industrial, and computing markets.

The MC74VHC245DTG belongs to the VHC logic family, designed specifically for high-speed, low-power bidirectional bus interfacing in mixed-voltage embedded systems with stringent reliability and ESD requirements.

FAQ

What is the maximum operating voltage for MC74VHC245DTG inputs?

The MC74VHC245DTG inputs tolerate voltages from −0.5 V to +6.5 V regardless of VCC level, enabling safe interfacing between 3.3 V and 5.0 V domains without external protection components. This specification is explicitly defined in the Maximum Ratings table of the official onsemi datasheet (Rev. 8, October 2024), and applies to all input pins including DIR, OE, and A/B bus terminals.

Can MC74VHC245DTG be used as a level shifter between 3.3 V and 5.0 V systems?

Yes, MC74VHC245DTG supports bidirectional level shifting: its inputs accept 5.0 V signals while operating from a 3.3 V VCC, and its outputs swing rail-to-rail (0 V to 3.3 V or 0 V to 5.0 V depending on VCC). However, it cannot directly translate 5 V outputs to 3.3 V inputs on the same bus due to internal parasitic diode limitations - external series resistors or dedicated level translators are required for that specific direction.

What is the propagation delay of MC74VHC245DTG at 3.3 V supply?

At VCC = 3.3 V ± 0.3 V with CL = 15 pF, the MC74VHC245DTG exhibits a typical propagation delay (tPLH/tPHL) of 5.8 ns and a maximum of 8.4 ns, as specified in the AC Electrical Characteristics table (page 4 of the datasheet). These values apply to both A→B and B→A data paths and are measured under standard load and temperature conditions.

Does MC74VHC245DTG support hot-swap operation?

Yes, MC74VHC245DTG supports hot-swap operation due to its power-down protection feature: when VCC = 0 V, the outputs remain in a high-impedance, non-destructive state even if input or bus voltages are present. This behavior is documented in the datasheet's "Features" section and validated by the VHCT variant's explicit 0 V supply protection architecture.

What package type is used for MC74VHC245DTG?

MC74VHC245DTG uses the TSSOP-20 (Thin Shrink Small Outline Package) with case outline 948E, featuring 0.65 mm lead pitch, 6.5 mm × 4.4 mm body dimensions, and Pb-free/RoHS-compliant construction. This information is confirmed in the Ordering Information table (page 9) and Mechanical Case Outline drawing (page 10) of the official onsemi datasheet.