Texas Instruments SN74LV8T245RKSR

Overview

SN74LV8T245RKSR from Texas Instruments is an octal bus transceiver with 3-state outputs and integrated logic-level translation, supporting bidirectional voltage translation between 1.2 V–5.5 V domains. It features DIR/OE dual-control logic, 5.5-V tolerant inputs, 1.65–5.5-V supply range, and operates across –40°C to 125°C for industrial interface bridging in mixed-voltage systems.

For engineers reviewing the SN74LV8T245RKSR datasheet, SN74LV8T245RKSR pinout, SN74LV8T245RKSR application, or SN74LV8T245RKSR equivalent, key selection criteria include verified up/down translation capability (e.g., 1.8 V ↔ 3.3 V), 3-state timing (t_pd = 4.5 ns @ 5 V), thermal performance (R_θJA = 67.7°C/W), latch-up immunity (>250 mA), and VQFN-20 wettable flank package compatibility with AOI inspection.

Technical Context

The SN74LV8T245RKSR implements shared DIR/OE control logic for all eight transceiver channels, enabling direction-selectable bidirectional data flow with simultaneous 3-state output disable. Its LVxT-enhanced input structure provides reduced VIH/VIL thresholds for reliable up-translation (e.g., 1.2 V → 1.8 V) and 5.5-V tolerant inputs for down-translation (e.g., 5 V → 1.8 V).

Output voltage levels are referenced strictly to VCC (1.65–5.5 V), supporting CMOS-compatible signaling at 1.8 V, 2.5 V, 3.3 V, and 5 V. Propagation delay scales inversely with supply voltage: 4.5 ns (min) @ 5 V/15 pF, 6.4 ns @ 3.3 V, 8.8 ns @ 2.5 V, and 11.8 ns @ 1.8 V - all specified over full temperature range (–40°C to 125°C).

Key Specifications

Pinout & Package

RKS package is a 20-pin VQFN (4.50 mm × 2.50 mm) with exposed thermal pad; footprint compatible with standard QFN reflow profiles and supports automated optical inspection via wettable flanks.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74AVC8T245RKL and TXB0108PWR, the SN74LV8T245RKSR uniquely supports 5.5-V tolerant inputs and 1.65–5.5-V operation in a thermally optimized RKS package - making it the only choice for robust 5-V-to-1.8-V down-translation in high-temperature industrial environments.

Availability

SN74LV8T245RKSR is available at Aetrix Electronics and suitable for industrial sensor interfaces, automotive body control modules, FPGA I/O expansion, and industrial Ethernet PHY interfaces requiring stable component supply across extended temperature and mixed-voltage conditions.

Supply support for SN74LV8T245RKSR 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

Texas Instruments is a global semiconductor leader specializing in analog, embedded processing, and connectivity technologies with over 90 years of innovation in industrial, automotive, and communications markets.

The SN74LV8T245RKSR belongs to TI's LVxT logic family, engineered specifically for seamless voltage-level translation in mixed-supply systems - targeting industrial automation, automotive ECUs, and programmable logic interconnects where reliability across wide voltage and temperature ranges is critical.

FAQ

What voltage translation combinations does the SN74LV8T245RKSR support?

The SN74LV8T245RKSR supports verified up-translation (e.g., 1.2 V → 1.8 V, 1.8 V → 3.3 V) and down-translation (e.g., 5 V → 3.3 V, 3.3 V → 1.8 V) based on VCC selection and input tolerance. With 5.5-V tolerant inputs and VCC ranging from 1.65 V to 5.5 V, the SN74LV8T245RKSR enables 16 distinct cross-voltage pairings documented in TI's SCLS907A datasheet Section 8.3.3.

How does the DIR and OE pin interaction affect bus behavior in the SN74LV8T245RKSR?

In the SN74LV8T245RKSR, DIR selects data direction (L = B→A, H = A→B), while OE enables/disables all outputs (L = active, H = high-Z). When OE is high, both A and B ports enter high-impedance regardless of DIR state - ensuring clean bus isolation during reset or sleep modes. This dual-control architecture prevents bus contention in multi-master systems.

Is the thermal pad on the SN74LV8T245RKSR package required to be connected to ground?

No - the thermal pad on the SN74LV8T245RKSR (RKS package) may be connected to GND or left electrically floating per TI's datasheet guidance. Connecting it to GND improves thermal dissipation by ~25%, but floating is acceptable if board layout constraints prohibit grounding. It must never be connected to any signal or supply voltage other than GND.

What is the maximum data rate supported by the SN74LV8T245RKSR in a real-world PCB layout?

The SN74LV8T245RKSR achieves up to 150 Mbps in controlled-impedance environments (e.g., 50-Ω traces, CL ≤ 15 pF). At 5 V VCC, its minimum propagation delay is 4.5 ns, allowing reliable operation at 220 MHz clock rates. Real-world throughput depends on trace length, load capacitance, and termination - TI validates 150 Mbps with 12-cm traces and series damping resistors per SLLA307 application note.

Does the SN74LV8T245RKSR require external pull-up resistors on DIR or OE pins?

OE should be pulled up to VCC via a 10-kΩ resistor to ensure high-impedance state during power-up/power-down, as specified in TI's SCLS907A Section 8.1. DIR has no such requirement - it may be driven directly by MCU GPIO or tied static high/low. Leaving OE floating risks undefined output states and potential bus contention during supply ramp.