Texas Instruments SN74LVCH244ADWR

Overview

SN74LVCH244ADWR from Texas Instruments is an octal buffer/line driver with 3-state outputs, designed for 1.65 V to 3.6 V operation. It features bus-hold circuitry on all data inputs, I_off partial-power-down support, and mixed-mode signal translation (5-V input compatible with 3.3-V V_CC). It is used in bidirectional data bus interfacing, memory address buffering, and level-shifting between 3.3-V and 5-V logic domains.

For engineers reviewing the SN74LVCH244ADWR datasheet, SN74LVCH244ADWR pinout, SN74LVCH244ADWR application, or SN74LVCH244ADWR equivalent, key selection criteria include its 20-pin SOIC-DW package, 5.9 ns max propagation delay at 3.3 V, ±24 mA output drive capability, bus-hold functionality eliminating external resistors, and I_off protection for hot-swap and power sequencing scenarios.

Technical Context

The SN74LVCH244ADWR implements two independent 4-bit noninverting buffers, each with dedicated output-enable (OE) control. Its bus-hold circuitry actively maintains valid logic states on undriven inputs without external pullup/pulldown resistors. The I_off feature disables outputs and blocks current backflow when V_CC = 0, enabling safe partial-power-down operation.

It supports mixed-voltage system interfacing: inputs tolerate up to 5.5 V regardless of V_CC, allowing direct connection to 5-V TTL outputs while operating from a 3.3-V or 1.8-V supply. Output voltage levels are referenced to V_CC, ensuring compatibility with downstream 3.3-V CMOS loads.

Key Specifications

Pinout & Package

SN74LVCH244ADWR is housed in a 20-pin SOIC (DW) package, 7.5 mm × 12.8 mm body size, 1.75 mm height, with 1.27 mm lead pitch and gull-wing leads. RoHS-compliant, NIPDAU lead finish, MSL Level-1.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74LVC244APWR and 74ALVC244MTCX, SN74LVCH244ADWR uniquely integrates bus-hold and I_off in a single SOIC package-reducing external components, simplifying layout, and enhancing robustness in uncontrolled power-up or noisy industrial environments.

Availability

SN74LVCH244ADWR is available at Aetrix Electronics and suitable for industrial automation controllers, embedded memory subsystems, and test equipment requiring stable component supply with full traceability and long-term lifecycle support.

Supply support for SN74LVCH244ADWR 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 high-reliability IC design.

The SN74LVCH244ADWR belongs to TI's LVCH logic family, engineered for low-voltage, mixed-signal interfacing in space-constrained industrial and communications systems where bus-hold, I_off, and 5-V tolerance are essential.

FAQ

What is the recommended operating voltage range for SN74LVCH244ADWR?

The SN74LVCH244ADWR operates from 1.65 V to 3.6 V. This range supports both 1.8-V and 3.3-V system designs. Operation below 1.65 V is not guaranteed per datasheet specifications, and exceeding 3.6 V may damage the device. The part retains data integrity down to 1.5 V, but functional operation is only assured within the specified 1.65–3.6 V window. Always verify V_CC stability under load using local decoupling.

Does SN74LVCH244ADWR require external pullup or pulldown resistors on its inputs?

No, SN74LVCH244ADWR does not require external pullup or pulldown resistors due to integrated bus-hold circuitry on all data inputs. This feature actively maintains a valid logic state on undriven or floating inputs. Using external resistors with bus-hold enabled may cause excessive current draw or logic instability and is explicitly discouraged in the datasheet.

Can SN74LVCH244ADWR safely interface a 5-V microcontroller output with a 3.3-V FPGA input?

Yes, SN74LVCH244ADWR can safely perform this level translation. Its inputs tolerate voltages up to 5.5 V regardless of V_CC, so a 5-V microcontroller output may drive any A-input directly. When powered from 3.3 V, the Y-outputs swing rail-to-rail (0 V to 3.3 V), making them fully compatible with 3.3-V FPGA I/O standards such as LVTTL or LVCMOS.

What is the maximum propagation delay of SN74LVCH244ADWR at 3.3 V?

The maximum propagation delay (t_pd) of SN74LVCH244ADWR is 5.9 ns when V_CC = 3.3 V and operating at 25°C. This value applies to the A → Y path under standard load conditions (C_L = 50 pF). Delay increases slightly at lower V_CC (e.g., 6.9 ns at 1.8 V) and with higher capacitive loads, so timing margins should be verified for each specific application.

How does the I_off feature of SN74LVCH244ADWR protect the system during power sequencing?

The I_off feature disables all outputs and blocks current flow through the device when V_CC = 0 V, limiting leakage to ±10 µA. This prevents back-driving of powered-down sections by active signals on A or Y pins-critical in hot-swap backplanes or multi-rail systems where subsystems power up/down asynchronously. SN74LVCH244ADWR remains safe even if inputs or outputs are driven while unpowered.