NXP Semiconductors.

80C51 8-bit microcontroller family 4K/8K/16K/32K ROM/OTP 128B/256B RAM low voltage (2.7 to 5.5 V), low power, high speed (30/33 MHz)

Rochester Electronics

POWERFUL MICROCONTROLLER from the MCS 51 controller family 40 pin DIP

Intel

MCS® 51 CHMOS SINGLE-CHIP 8-BIT MICROCONTROLLER

Intel

33 MHz CHMOS SINGLE-CHIP 8-BIT MICROCONTROLLERS

Philips Electronics

Low-voltage single-chip 8-bit microcontrollers

Philips Electronics

Low voltage 8-bit microcontrollers with UART

Philips Electronics

Low-voltage single-chip 8-bit microcontrollers

Philips Electronics

Low voltage 8-bit microcontrollers with UART

Rochester Electronics

POWERFUL MICROCONTROLLER from the MCS 51 controller family 40 pin DIP

Philips Electronics

Low voltage 8-bit microcontrollers with UART

Intel

CHMOS SINGLE-CHIP 8-BIT MICROCONTROLLERS

Intel

CHMOS SINGLE-CHIP 8-BIT MICROCONTROLLER

Philips Electronics

Low-voltage single-chip 8-bit microcontrollers

Philips Electronics

80C51 8-bit microcontroller family 4K/8K/16K/32K ROM/OTP 128B/256B RAM low voltage (2.7 to 5.5 V), low power, high speed (30/33 MHz)