Texas Instruments SN74LVCH245DWR

Overview

SN74LVCH245DWR from Texas Instruments is an octal bus transceiver with 3-state outputs, designed for 2.7-V to 3.6-V V_CC operation and mixed-mode interfacing (5-V I/O with 3.3-V V_CC). It supports bidirectional data flow between A and B buses under DIR control, features bus-hold on all data inputs, and operates across –40°C to 85°C. Used in level-shifting backplane interfaces and isolated bus domains.

For engineers reviewing the SN74LVCH245DWR datasheet, SN74LVCH245DWR pinout, SN74LVCH245DWR application, or SN74LVCH245DWR equivalent, key selection criteria include 3-state isolation timing (t_dis ≤ 8.5 ns at 2.7 V), bus-hold elimination of external pullups, ±24-mA drive strength at 3 V, and absolute input tolerance up to 5.5 V.

Technical Context

The SN74LVCH245DWR implements asynchronous bidirectional data routing using a single DIR input to select A→B or B→A direction, and an active-low OE input to enable/disable all outputs into high-impedance state. Its EPIC™ submicron CMOS process ensures low ground bounce (V_OLP < 0.8 V) and undershoot control (V_OHV > 2 V) at 3.3 V.

Bus-hold circuitry actively maintains valid logic levels on floating A1–A8 and B1–B8 inputs without external components, while absolute maximum ratings allow safe operation with 5.5-V inputs and 6.5-V supply-critical for legacy 5-V system integration into 3.3-V domains.

Key Specifications

Pinout & Package

SN74LVCH245DWR uses a 20-pin SOIC (DW) package with 0.300-inch body width and standard pin pitch. Pin 1 is DIR, pin 2 is A1, continuing sequentially to pin 10 (GND), then pin 11 (V_CC), pin 12 (OE), and pins 13–20 assigned to B1–B8.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 74LVC245ADTR and SN74AVC245DWR, the SN74LVCH245DWR uniquely combines 5-V-tolerant I/O, integrated bus-hold, and industrial temperature range in a cost-optimized SOIC package-making it optimal for retrofitting legacy 5-V peripherals into modern 3.3-V control systems without redesigning bias networks or adding protection components.

Availability

SN74LVCH245DWR is available at Aetrix Electronics and suitable for industrial backplanes, microcontroller expansion interfaces, and automated test equipment requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.

Supply support for SN74LVCH245DWR 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 delivering analog, embedded processing, and connectivity solutions for industrial, automotive, and personal electronics markets.

The SN74LVCH245DWR belongs to TI's LVCH logic family, engineered specifically for robust mixed-voltage system interfacing-emphasizing 5-V tolerance, bus-hold stability, and noise-immune operation in harsh industrial environments.

FAQ

What is the maximum input voltage the SN74LVCH245DWR can tolerate on its data pins?

The SN74LVCH245DWR supports input voltages up to 5.5 V on all A and B port pins, regardless of V_CC level. This 5-V tolerance enables direct connection to legacy 5-V logic without external level-shifting circuitry. The specification is validated per absolute maximum ratings and confirmed in the recommended operating conditions table. This capability is intrinsic to the SN74LVCH245DWR's input structure and applies across its full temperature range.

Does the SN74LVCH245DWR require external pullup resistors on its data inputs?

No, the SN74LVCH245DWR does not require external pullup resistors due to integrated bus-hold circuitry on all A1–A8 and B1–B8 inputs. This feature actively maintains the last-valid logic state on floating or unterminated inputs, with ±75 µA hold current specified at V_I = 2 V. The bus-hold function is always active and eliminates the need for 16 discrete resistors, simplifying layout and improving reliability in the SN74LVCH245DWR-based design.

What is the propagation delay of the SN74LVCH245DWR at 3.3 V?

The SN74LVCH245DWR has a typical propagation delay (t_pd) of 1.5 ns and a maximum of 7 ns at V_CC = 3.3 V ± 0.3 V with C_L = 50 pF. This value applies to both A→B and B→A data paths and is measured under standard switching conditions defined in the datasheet. The low t_pd ensures minimal latency in high-speed bus arbitration and real-time data forwarding applications using the SN74LVCH245DWR.

How should the OE pin of the SN74LVCH245DWR be handled during power-up?

To ensure high-impedance state during power-up or power-down, the OE pin of the SN74LVCH245DWR must be tied to V_CC through a pullup resistor. The minimum resistor value depends on the current-sinking capability of the driving source; TI recommends verifying driver strength to avoid violating the OE input current limit. This precaution prevents unintended bus contention and is critical for system-level reliability in the SN74LVCH245DWR implementation.

Is the SN74LVCH245DWR compatible with 2.7-V operation?

Yes, the SN74LVCH245DWR is fully specified for 2.7-V V_CC operation, with guaranteed performance across the entire 2.7–3.6-V range. At 2.7 V, it delivers ±12-mA output drive and supports t_pd ≤ 8 ns, meeting industrial requirements for battery-backed or low-power systems. All electrical characteristics-including VIH/VIL thresholds and bus-hold behavior-are validated down to 2.7 V, confirming robust functionality of the SN74LVCH245DWR in low-voltage deployments.