onsemi 74ABT2244CMTC

Overview

74ABT2244CMTC from Fairchild Semiconductor is an octal non-inverting buffer/line driver with integrated 25Ω series output resistors, designed for driving capacitive bus loads in memory, address, and clock distribution systems. It operates from 4.5V to 5.5V, delivers 32mA sink current per output, supports 3.9ns max propagation delay, and features hot-insertion capability with glitch-free power-up/down behavior.

For engineers reviewing the 74ABT2244CMTC datasheet, pinout, applications, or equivalent options, key selection criteria include its built-in 25Ω output termination, dual independent 3-state control (OE1/OE2), TSSOP-20 package compatibility, and guaranteed latchup protection under JEDEC J-STD-020B Pb-free compliance.

Technical Context

The 74ABT2244CMTC implements two independent 4-bit groups (I0–I3/O0–O3 and I4–I7/O4–O7), each controlled by a dedicated active-low output enable (OE1, OE2). Its ABT logic family ensures TTL-compatible input thresholds (VIH = 2.0V, VIL = 0.8V) and fast AC performance (tPLH/tPHL ≤ 3.9ns at CL = 50pF).

Each output integrates a 25Ω series resistor to dampen signal reflections on transmission lines, eliminating discrete termination components. The device maintains high-impedance outputs during power sequencing, preventing bus contention and enabling live insertion into powered backplanes.

Key Specifications

Pinout & Package

74ABT2244CMTC is housed in a 20-pin Thin Shrink Small Outline Package (TSSOP), JEDEC MO-153 compliant, with 0.65mm lead pitch and 4.4mm body width. Pin 1 is marked by a dot or beveled corner; pins are numbered counter-clockwise.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74ABT2244DBR and 74LVT2244MTCX, the 74ABT2244CMTC uniquely combines 5V operation, built-in 25Ω termination, and verified hot-insertion capability - making it the only choice for legacy 5V backplane upgrades requiring zero-layout changes and live-serviceability.

Availability

74ABT2244CMTC is available at Aetrix Electronics and suitable for memory subsystem buffering, industrial backplane interfaces, and legacy bus adaptation requiring stable component supply, long-term lifecycle support, and Pb-free compliance.

Supply support for 74ABT2244CMTC 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

Fairchild Semiconductor was a U.S.-based semiconductor company specializing in analog and mixed-signal ICs, acquired by ON Semiconductor in 2016. Its ABT logic family delivered high-speed, low-noise performance for industrial and computing applications.

The 74ABT2244 belongs to Fairchild's Advanced BiCMOS Technology (ABT) logic series, engineered specifically for high-frequency bus driving in memory, address, and clock distribution systems where signal integrity and hot-swap reliability are critical.

FAQ

What is the maximum operating temperature range for the 74ABT2244CMTC?

The 74ABT2244CMTC is rated for operation from –40°C to +85°C ambient temperature, as defined in the Recommended Operating Conditions table. This range covers commercial and industrial environments, including enclosed PLC cabinets and telecom line cards. Junction temperature must not exceed +150°C under bias, and storage temperature extends to –65°C to +150°C. Thermal derating is not required within the specified ambient range when proper PCB copper pour and decoupling are applied.

Does the 74ABT2244CMTC require external pull-up or pull-down resistors on its OE pins?

No, the 74ABT2244CMTC does not require external pull-up or pull-down resistors on OE1 or OE2. Its inputs are TTL-compatible with defined VIH (2.0V) and VIL (0.8V) thresholds, and internal circuitry ensures predictable 3-state behavior when OE is left unconnected (floating) - though best practice recommends tying unused OE pins to VCC or GND via 10kΩ resistors to prevent noise-induced toggling. The device guarantees glitch-free behavior even during floating transitions.

Can the 74ABT2244CMTC drive a 75Ω coaxial cable directly?

No, the 74ABT2244CMTC cannot drive a 75Ω coaxial cable directly. Its integrated 25Ω series resistors are optimized for PCB trace impedance matching (typically 50–60Ω), not 75Ω video or RF lines. Driving 75Ω loads would result in significant signal reflection and amplitude loss. For coaxial applications, use a dedicated 75Ω line driver IC or add external series termination to achieve proper impedance matching - the 74ABT2244CMTC remains ideal for board-level bus routing, not cable interconnects.

Is the 74ABT2244CMTC pin-compatible with the 74ABT2240 or 74ABT2245?

No, the 74ABT2244CMTC is not pin-compatible with the 74ABT2240 or 74ABT2245. The 74ABT2240 is an octal inverting buffer (inverting logic function), while the 74ABT2245 is an octal bus transceiver with bidirectional flow and different pin assignments (e.g., DIR pin instead of dual OE). Although all three share the same TSSOP-20 package footprint, their pinouts differ significantly - particularly in control signal placement and I/O directionality - requiring PCB layout changes for substitution.

What is the purpose of the 25Ω series resistors in the 74ABT2244CMTC outputs?

The 25Ω series resistors in the 74ABT2244CMTC outputs serve to dampen signal reflections on PCB traces by approximating series termination for typical 50Ω–60Ω characteristic impedances. They reduce overshoot, undershoot, and ringing during fast edge transitions, improving signal integrity without requiring discrete resistors. These resistors are monolithically integrated into each output stage and do not affect DC drive capability - the device still delivers full 32mA sink current while providing controlled rise/fall times suitable for 20+ MHz bus operation.