Texas Instruments SN74LVCH244APW

Overview

SN74LVCH244APW from Texas Instruments is an octal noninverting buffer/driver with 3-state outputs, designed for 1.65-V to 3.6-V V_CC operation. It features bus-hold circuitry on all data inputs, I_off partial-power-down support, 5.5-V tolerant inputs, and a maximum 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 between microcontrollers and peripheral buses.

For engineers reviewing the SN74LVCH244APW datasheet, SN74LVCH244APW pinout, SN74LVCH244APW application, or SN74LVCH244APW equivalent, key selection criteria include its 20-pin TSSOP package, dual 4-bit channel architecture with independent output-enable controls, bus-hold elimination of external pull resistors, and compatibility with both 3.3-V and 5-V logic levels on inputs.

Technical Context

The SN74LVCH244APW implements two independent 4-bit noninverting buffer sections (1A→1Y and 2A→2Y), each controlled by its own active-low output-enable (OE) input. Its bus-hold circuitry maintains valid logic states on undriven inputs without external components, and I_off protection disables outputs during power-down to prevent backflow current.

Input voltage tolerance up to 5.5 V enables use as a level translator in mixed-mode systems, while the 3-state outputs support shared-bus applications. The device operates across –40°C to 85°C and meets JESD 22 ESD standards (2000-V HBM, 200-V MM, 1000-V CDM).

Key Specifications

Pinout & Package

TSSOP-20 (PW) package: 6.5 mm × 4.4 mm, 0.65 mm pitch, 1.2 mm max height, 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 SN74LVC244APW and 74AVC244T, the SN74LVCH244APW uniquely combines 5-V input tolerance, integrated bus-hold, and I_off protection-making it optimal for industrial mixed-voltage expansion where reliability and BOM simplification are prioritized over minimal static current.

Availability

SN74LVCH244APW is available at Aetrix Electronics and suitable for industrial I/O expansion, mixed-voltage bus interfacing, and test equipment signal conditioning requiring stable component supply and long-term lifecycle support.

Supply support for SN74LVCH244APW 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 precision analog, power management, and logic ICs.

The SN74LVCH244APW belongs to TI's LVCH logic family, engineered for robust mixed-signal interfacing in industrial and automotive systems where voltage translation, bus stability, and power-down safety are critical design requirements.

FAQ

What is the maximum operating voltage for SN74LVCH244APW inputs?

The SN74LVCH244APW inputs tolerate up to 5.5 V regardless of V_CC level, enabling safe connection to 5-V TTL or CMOS outputs while powered from 1.65–3.6 V supplies. This specification is guaranteed across the full operating temperature range and eliminates the need for external level-shifting circuitry in mixed-voltage designs involving the SN74LVCH244APW.

Does SN74LVCH244APW require external pullup resistors on unused inputs?

No. The SN74LVCH244APW integrates active bus-hold circuitry on all data inputs, which maintains a valid logic state on floating or undriven pins without external components. Using pullup or pulldown resistors with the SN74LVCH244APW is explicitly discouraged in the datasheet, as it may interfere with bus-hold functionality and increase power consumption.

How does the I_off feature protect the SN74LVCH244APW during partial power-down?

The I_off circuitry in the SN74LVCH244APW disables all outputs when V_CC = 0 V, limiting leakage current to ±10 µA even if input or output pins are driven to 5.5 V. This prevents damaging reverse current flow through the SN74LVCH244APW during hot-swap or staggered power sequencing scenarios, ensuring system-level robustness without additional protection circuitry.

What is the typical propagation delay of SN74LVCH244APW at 1.8 V supply?

At V_CC = 1.8 V, the typical propagation delay (t_pd) of the SN74LVCH244APW is 6.9 ns, as specified in the switching characteristics table. This value is measured under standard load conditions (30 pF, 10 MHz) and reflects the actual timing performance achievable in low-voltage portable or battery-powered applications using the SN74LVCH244APW.

Can SN74LVCH244APW be used as a drop-in replacement for SN74LVC244APW?

No. While pin-compatible, the SN74LVCH244APW includes bus-hold and different I_off behavior versus the SN74LVC244APW. Replacing SN74LVC244APW with SN74LVCH244APW may cause unintended logic states on floating inputs due to active bus-hold, and requires verification of OE control timing and power-down sequencing. Direct substitution is not recommended without circuit-level validation for the SN74LVCH244APW.