Texas Instruments SN74LVCH244ADW

Overview

SN74LVCH244ADW from Texas Instruments is an octal buffer/line driver with 3-state outputs, designed for 1.65-V to 3.6-V VCC operation. It features two independent 4-bit channels, bus-hold circuitry on all inputs, Ioff partial-power-down support, and mixed-mode 5-V-input/3.3-V-output compatibility-enabling use in voltage-translating data paths of industrial control backplanes.

For engineers reviewing the SN74LVCH244ADW datasheet, SN74LVCH244ADW pinout, SN74LVCH244ADW application, or SN74LVCH244ADW equivalent, key selection criteria include its 5.9 ns max propagation delay at 3.3 V, ±24 mA output drive capability, 20-pin SOIC (DW) package with 0.65 mm pitch, and guaranteed operation across –40°C to +85°C.

Technical Context

The SN74LVCH244ADW implements dual 4-bit noninverting buffers with independent 3-state enable controls (1OE and 2OE), each gating one channel's Y outputs. Its bus-hold circuitry actively maintains valid logic states on undriven A inputs without external resistors-reducing BOM count and layout complexity in high-impedance bus environments.

Designed for mixed-voltage systems, it accepts 0–5.5 V input voltages while operating from 1.65–3.6 V VCC, enabling direct interfacing between legacy 5-V logic and modern low-voltage microcontrollers. The Ioff feature disables outputs during power-down, preventing damaging current backflow when VCC = 0 V.

Key Specifications

Pinout & Package

SN74LVCH244ADW uses a 20-pin SOIC (DW) package measuring 7.5 mm × 12.8 mm with 0.65 mm lead pitch and gull-wing leads. Pin 1 is located at the top-left corner adjacent to the index notch.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74LVC244APWR and 74ALVC244MTCX, the SN74LVCH244ADW uniquely combines bus-hold, Ioff, and 5-V-tolerant inputs in a single SOIC-20 package-making it the only option among the three that eliminates external bias components and guarantees safe operation during power sequencing.

Availability

SN74LVCH244ADW is available at Aetrix Electronics and suitable for industrial automation, test equipment, and embedded control applications requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for SN74LVCH244ADW 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 communications markets.

The SN74LVCH244ADW belongs to TI's LVC/LVCH logic family-engineered for low-voltage, high-speed, mixed-signal interfacing in space-constrained industrial and instrumentation systems.

FAQ

What is the maximum propagation delay of the SN74LVCH244ADW at 3.3 V?

The SN74LVCH244ADW has a maximum propagation delay (tpd) of 5.9 ns when VCC = 3.3 V and TA = 25°C. This value is measured from input transition to output transition under specified load conditions (CL = 50 pF). At lower VCC (e.g., 1.8 V), tpd increases to 6.9 ns, confirming its performance scalability across the full 1.65–3.6 V operating range. The SN74LVCH244ADW maintains timing predictability across temperature and voltage corners.

Does the SN74LVCH244ADW require external pullup resistors on its inputs?

No, the SN74LVCH244ADW does not require external pullup or pulldown resistors on its inputs because it integrates active bus-hold circuitry on all eight A inputs. This feature maintains valid logic states on undriven or floating inputs, eliminating risk of metastability and reducing BOM count. Using external resistors with the SN74LVCH244ADW is explicitly discouraged in the datasheet, as it may interfere with bus-hold operation and increase power consumption.

Can the SN74LVCH244ADW safely interface a 5-V microcontroller with a 3.3-V FPGA?

Yes, the SN74LVCH244ADW can safely interface a 5-V microcontroller with a 3.3-V FPGA. Its inputs tolerate up to 5.5 V regardless of VCC level, allowing direct connection of 5-V logic outputs to the A pins while VCC is supplied at 3.3 V. The outputs swing rail-to-rail within the 3.3-V domain, matching FPGA I/O thresholds. This bidirectional voltage translation capability is inherent to the SN74LVCH244ADW design and requires no additional components.

What is the thermal resistance (θJA) of the SN74LVCH244ADW in its SOIC (DW) package?

The SN74LVCH244ADW in the SOIC (DW) package has a junction-to-ambient thermal resistance (θJA) of 58°C/W, as specified in the TI datasheet under standard JEDEC test conditions (1-layer board, 1 in² copper pad). This value assumes proper PCB layout with adequate copper pour and thermal vias near the GND and VCC pins. For sustained 24 mA per output operation, junction temperature rise remains within safe limits up to +85°C ambient when mounted on a typical 2-layer board.

Is the SN74LVCH244ADW compatible with lead-free reflow processes?

Yes, the SN74LVCH244ADW is fully compatible with lead-free reflow processes. It carries a "Level-1-260C-UNLIM" moisture sensitivity level rating and is qualified for peak reflow temperatures up to 260°C, consistent with IPC/JEDEC J-STD-020 requirements. The device uses NiPdAu (NIPDAU) lead finish and is RoHS-compliant. No special bake or handling procedures are required prior to assembly, provided humidity exposure remains within MSL-1 limits.