Diodes Incorporated 74LVT245BBT20-13

Overview

74LVT245BBT20-13 from Diodes Incorporated is a 3.3 V octal bus transceiver with 3-state outputs, designed for bidirectional asynchronous data transfer between A and B buses in mixed-voltage systems. It features 20-pin TSSOP packaging, 2.7–3.6 V supply operation, 5.5 V-tolerant inputs, and IOFF-enabled partial power-down isolation. Used in server motherboard I/O expansion and notebook chipset interconnects.

For engineers reviewing the 74LVT245BBT20-13 datasheet, 74LVT245BBT20-13 pinout, 74LVT245BBT20-13 application, or 74LVT245BBT20-13 equivalent, key selection criteria include direction-control logic behavior, 3-state enable timing (tPZH/tPHZ ≤ 7.7 ns at 3.3 V), bus-hold input retention, and thermal resistance (θJA = 74 °C/W) for high-density PCB layouts.

Technical Context

The device implements dual 8-bit bidirectional data paths controlled by DIR (pin 1) and OE (pin 19), enabling A→B or B→A transmission under active-low output enable. Its CMOS-based LVT logic family ensures TTL-compatible thresholds while maintaining low static current (ICC ≤ 0.19 mA when outputs disabled).

IOFF circuitry actively disables outputs during VCC ramp-down to prevent backflow current; bus-hold inputs eliminate external pull resistors on unused lines. Schmitt-trigger inputs provide noise immunity, and hot-insertion-safe power-up 3-state behavior avoids bus contention during system initialization.

Key Specifications

Pinout & Package

TSSOP-20 package: 6.4 mm × 6.5 mm × 1.2 mm body, 0.65 mm lead pitch, exposed pad not present, JEDEC MO-153 compliant.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74LVC245APWR and 74ALVC245MTCX, the 74LVT245BBT20-13 uniquely combines IOFF, bus-hold, and 5.5 V tolerance in a single 3.3 V transceiver - making it the only choice for thermally constrained, mixed-voltage, hot-pluggable systems requiring zero external biasing or isolation components.

Availability

74LVT245BBT20-13 is available at Aetrix Electronics and suitable for server motherboard design, notebook platform integration, and industrial PLC backplane development requiring stable component supply and long-term lifecycle support.

Supply support for 74LVT245BBT20-13 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

Diodes Incorporated is a global manufacturer of discrete semiconductors and analog ICs, specializing in high-reliability power management, signal integrity, and protection devices for computing, industrial, and communications markets.

The 74LVT245BB belongs to Diodes' LVT logic family, engineered specifically for high-speed, low-power bidirectional bus interfacing in mixed-voltage computing platforms where signal integrity, thermal efficiency, and system-level power sequencing are critical.

FAQ

What is the maximum allowable output current per pin for continuous operation?

The 74LVT245BBT20-13 supports 64 mA sink current per output pin at 3.0 V supply, but only with ≤50% duty cycle and frequency >1 kHz. For DC or high-duty-cycle operation, limit to 32 mA per pin to maintain VOL ≤ 0.4 V and avoid thermal derating beyond 125 °C junction temperature.

Does this device require external pull-up or pull-down resistors on unused inputs?

No. All A and B port inputs feature integrated bus-hold circuitry that maintains the last valid logic state without external resistors. Control inputs (DIR and OE) should still be actively driven or tied to VCC/GND per recommended operating conditions to prevent metastability.

Can the 74LVT245BBT20-13 safely interface between a 3.3 V microcontroller and a 5 V sensor bus?

Yes - its inputs tolerate up to 5.5 V regardless of VCC level, allowing direct connection of 5 V sensor outputs to A/B ports. However, outputs sourced from the device remain limited to VCC (3.3 V), so external level-shifting is required for driving 5 V inputs unless the receiving device accepts 3.3 V logic-high thresholds.

How does the IOFF feature behave during power-down sequences?

When VCC drops below 0.8 V, the IOFF circuit automatically places all outputs in high-impedance state, blocking reverse current flow from powered bus segments into the de-energized device. This prevents latch-up and protects upstream drivers during asymmetric power cycling in multi-rail systems.