onsemi MC74VHC244/MC74VHCT244A Octal Bus Buffers
onsemi MC74VHC244 and MC74VHCT244A Octal Bus Buffers are high‑speed CMOS octal non‑inverting bus buffers designed for robust, low‑power digital signal buffering in a wide range of system architectures. Built using advanced silicon‑gate CMOS technology, these devices deliver fast propagation delays, high noise immunity, and balanced signal timing, making the onsemi MC74VHC244 and MC74VHCT244A ideal for high‑performance computing and communication designs.
Each buffer includes two active‑low 3‑state output enable controls, allowing flexible bus management and efficient isolation in shared‑line environments. The input structures are designed to tolerate voltages up to 5.5V, enabling safe interfacing between 5V and 3V systems, and providing protection in conditions such as mismatched supply domains, battery‑backup configurations, or hot‑insertion events. The MC74VHCT244A variant features TTL‑compatible inputs and full 5V CMOS‑level output swings, supporting seamless level shifting between 3.3V and 5.0V logic families.
Internally, the onsemi MC74VHC244 and MC74VHCT244A devices incorporate multi‑stage buffering for stable, noise‑resistant output behavior. Engineered for reliability, the buffers include power‑down protection on inputs, latchup immunity exceeding 100mA, and ESD protection above 2000V (HBM). Offering low dynamic switching noise and compatibility with standard logic pinouts, these octal bus buffers are well-suited for memory address driving, clock distribution, and general-purpose bus‑oriented data transmission applications.
Features
- High speed
- tPD = 3.8ns typical at VCC = 5.0V (VHC)
- tPD = 5.6ns typical at VCC = 5.0V (VHCT)
- Low 4.0µA (maximum) power dissipation at +25°C
- High noise immunity - VNIH = VNIL = 28%
- Power-down protection provided
- Balanced propagation delays
- Designed for
- 2.0V to 5.5V (VHC)
- 4.5V to 5.5V (VHCT)
- Low noise
- VOLP = 0.8V maximum (VHC)
- VOLP = 1.1V maximum (VHCT)
- Pin and function compatible with other standard logic families
- Latchup performance exceeds 100mA
- >2000V ESD performance (HBM)
- 136 FETs chip complexity
- SOIC-20 and TSSOP-20 package options
- -Q suffix for automotive and other applications requiring unique site and control change requirements, AEC-Q100 qualified and PPAP capable
- Lead-free, Halogen-free, and RoHS-compliant
Applications
- 3‑state memory address driving
- Clock driving
- Bus‑oriented transmitter/receiver functions
- Level translation between 5V and 3V systems
- Mixed‑voltage interfacing
Specifications
- ±20mA maximum DC input current per pin
- ±25mA maximum DC output current per pin
- ±75mA maximum DC supply current, VCC and GND pins
- -20mA maximum input clamp current
- Maximum output clamp current
- ±20mA for MC74VHC244
- -20mA for MC74VHCT244A
- Maximum power dissipation in still air at +25°C
- 1302mW for SOIC-20W package
- 833mW for TSSOP-20 package
- Power dissipation capacitance
- 19pF for MC74VHC244
- 18pF for MC74VHCT244A
- ±100mA maximum latchup performance
- -55°C to +125°C operating temperature range
- +260°C maximum lead solder temperature, 1mm from the case for 10s
- +150°C maximum junction temperature under bias
- Maximum thermal resistance
- 96°C/W for SOIC-20W package
- 150°C/W for TSSOP-20 package
- Moisture Sensitivity LEVEL (MSL)
- Level 3 for SOIC-20W package
- Level 1 for all other packages
- UL 94V-0 flammability rating at 0.244"
Logic Diagram
