Texas Instruments SN74LVCH244ADBQR

Overview

SN74LVCH244ADBQR from Texas Instruments is an octal noninverting buffer/driver with 3-state outputs, designed for 1.65-V to 3.6-V VCC operation. It features bus-hold circuitry on all data inputs, Ioff partial-power-down support, 5.5-V tolerant inputs, and a max propagation delay of 5.9 ns at 3.3 V. It is used in mixed-voltage 3.3-V/5-V system interfacing, such as FPGA-to-ASIC signal translation in industrial control backplanes.

For engineers reviewing the SN74LVCH244ADBQR datasheet, SN74LVCH244ADBQR pinout, SN74LVCH244ADBQR application, or SN74LVCH244ADBQR equivalent, key selection criteria include 3-state output control timing (tdis ≤ 5.8 ns), bus-hold current (±45 µA at 2.3 V), Ioff leakage (< ±10 µA), and SSOP-20 package thermal impedance (68 °C/W).

Technical Context

The SN74LVCH244ADBQR 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 A-inputs without external resistors, eliminating floating node risks in high-impedance bus environments.

It supports mixed-mode signaling: inputs accept 0–5.5 V regardless of VCC (1.65–3.6 V), enabling level translation between 5-V legacy peripherals and 3.3-V or lower-core logic. The Ioff feature disables outputs during power-down to prevent backflow current when VCC = 0 V.

Key Specifications

Pinout & Package

SN74LVCH244ADBQR is housed in a 20-pin SSOP (Shrink Small Outline Package) with 0.65-mm lead pitch, 7.4-mm body width, and 2-mm max height per JEDEC MO-150. Pin 1 is located at the top-left corner with a molded 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, SN74LVCH244ADBQR uniquely combines bus-hold, Ioff, and 5.5-V input tolerance in a single SSOP-20 package - essential for robust, low-BOM-count designs in variable-voltage industrial environments.

Availability

SN74LVCH244ADBQR is available at Aetrix Electronics and suitable for industrial automation, automotive body electronics, FPGA interface design, and test equipment requiring stable component supply and long-term manufacturability.

Supply support for SN74LVCH244ADBQR 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 and embedded processing solutions, with over 90 years of innovation in industrial, automotive, and communications markets.

The SN74LVCH244ADBQR belongs to TI's LVCH logic family, engineered for low-voltage, mixed-signal interfacing with emphasis on robustness, power efficiency, and ease of integration in real-world PCB environments.

FAQ

What is the maximum operating temperature range for SN74LVCH244ADBQR?

The SN74LVCH244ADBQR is rated for operation from –40°C to +85°C ambient temperature, as confirmed in TI's official packaging addendum and recommended operating conditions table. This industrial temperature grade makes SN74LVCH244ADBQR suitable for deployment in factory-floor controllers, outdoor gateways, and automotive cabin modules where thermal cycling is expected. All electrical specifications in the datasheet are guaranteed across this full range.

Does SN74LVCH244ADBQR support hot insertion or live board swapping?

Yes, SN74LVCH244ADBQR supports hot insertion via its Ioff protection feature, which disables outputs and limits leakage to < ±10 µA when VCC = 0 V. This prevents back-current flow from powered downstream circuits into the unpowered IC, satisfying IEC 61000-4-2 and system-level hot-swap safety requirements. However, OE pins must be pulled to VCC (not left floating) during insertion to ensure outputs remain in high-Z state until power stabilizes.

Can SN74LVCH244ADBQR drive 50-Ω transmission lines directly?

Yes, SN74LVCH244ADBQR can drive 50-Ω transmission lines directly: its output drive strength reaches ±24 mA at VCC = 3 V, sufficient to source/sink 3.3 V into 50 Ω (66 mA required for full swing). While not optimized for RF impedance matching, it meets setup/hold and edge-rate requirements (≤10 ns/V) for baseband digital signaling up to 100 Mbps. For longer traces (>15 cm), series termination at the driver is recommended to suppress reflections.

How does the bus-hold function behave when VCC is below 1.65 V?

The bus-hold circuitry in SN74LVCH244ADBQR is specified only down to VCC = 1.65 V - the minimum recommended operating voltage. Below this threshold, bus-hold current is not characterized and may fall outside the ±45 µA typical range at 2.3 V. TI does not guarantee bus-hold functionality during brownout or power-rail ramp-up; for reliable hold behavior, maintain VCC ≥ 1.65 V before applying input signals.

Is SN74LVCH244ADBQR pin-compatible with SN74LVC244A devices?

Yes, SN74LVCH244ADBQR is pin-compatible with SN74LVC244APWR and SN74LVC244ADBR in the same SSOP-20 (DBQ/DB) footprint, sharing identical pin numbering, function mapping, and mechanical dimensions. However, SN74LVCH244ADBQR adds bus-hold and Ioff features absent in LVC variants - no PCB redesign is needed for drop-in replacement, but firmware must account for active bus-hold behavior on unused inputs.