ST72121 Microcontroller Technical Summary

Overview

The ST72121 is an HCMOS Microcontroller Unit (MCU) designed for embedded applications requiring high performance and low power consumption. It features an 8-bit CPU core with a rich set of peripherals, making it suitable for a wide range of industrial and consumer applications. The microcontroller operates within a supply voltage range of 3V to 6V and supports a maximum CPU frequency of 8 MHz (with a 16 MHz oscillator). It is available in both OTP (One-Time Programmable) and EPROM versions, providing flexibility for development and production.

Features

• CPU Core: 8-bit ST7 architecture with up to 8 MHz operating frequency.
• Memory:
  • Program Memory: 8K or 16K bytes (depending on variant).
  • RAM: 384 bytes (256 bytes stack) or 512 bytes (256 bytes stack).
• Peripherals:
  • Watchdog Timer (WDG).
  • 16-bit Timer with multiple operating modes.
  • Serial Communications Interface (SCI) for UART functionality.
  • Serial Peripheral Interface (SPI) for high-speed communication.
  • Multiple I/O Ports with configurable input/output modes.
• Power Management: Supports multiple low-power modes including Slow, Wait, and Halt modes.
• Reset Options: External reset, power-on reset, and optional Low Voltage Detector (LVD) reset.
• Operating Temperature: -40°C to +85°C.
• Package Options: TQFP44 and SDIP42.

Applications

The ST72121 microcontroller is well-suited for a variety of embedded applications, including:

• Industrial control systems.
• Consumer electronics.
• Automotive subsystems.
• Home automation.
• Sensor interfacing and data acquisition.
• Communication modules.

Electrical Characteristics

Absolute Maximum Ratings

• Supply Voltage (V_DD): -0.3V to +7V.
• Input Voltage (V_IN): -0.3V to V_DD + 0.3V.
• Operating Temperature: -40°C to +85°C.
• Storage Temperature: -65°C to +150°C.

Recommended Operating Conditions

• Supply Voltage (V_DD): 3.0V to 6.0V.
• Operating Frequency: Up to 8 MHz (with 16 MHz oscillator).
• Ambient Temperature: -40°C to +85°C.

DC Electrical Characteristics

• Input High Voltage (V_IH): 0.7 × V_DD (min).
• Input Low Voltage (V_IL): 0.3 × V_DD (max).
• Output High Voltage (V_OH): V_DD - 0.5V (min) at I_OH = -10 mA.
• Output Low Voltage (V_OL): 0.5V (max) at I_OL = 10 mA.
• Power Consumption:
  • Active Mode: 5 mA (typical) at 8 MHz.
  • Halt Mode: 10 µA (typical).

Oscillator Characteristics

• External Crystal Frequency: 1 MHz to 16 MHz.
• Start-up Time: Typically 10 ms.
• Clock Stability: ±1% over temperature range.

Peripheral Characteristics

• SCI Baud Rate: Up to 115.2 kbps.
• SPI Clock Frequency: Up to 4 MHz (master mode).
• Timer Resolution: 16-bit with programmable prescaler.
• Watchdog Timeout: Programmable from 1 ms to 1 s.

Package Information

The ST72121 is available in two package options:

• TQFP44: Thin Quad Flat Package with 44 pins (10 mm × 10 mm).
• SDIP42: Shrink Dual In-line Package with 42 pins (600 mil width).

Mechanical Data

• TQFP44:
  • Body Size: 10 mm × 10 mm.
  • Lead Pitch: 0.8 mm.
  • Height: 1.2 mm (max).
• SDIP42:
  • Body Size: 600 mil width.
  • Lead Pitch: 100 mil.
  • Height: 4.5 mm (max).

Ordering Information

The ST72121 is available in multiple variants, including OTP and EPROM versions:

• ST72T121J4: OTP version with 16K program memory.
• ST72E121J4: EPROM version with 16K program memory.

Custom code transfer services are available for production orders.

Conclusion

The ST72121 microcontroller is a versatile and robust solution for embedded systems requiring an 8-bit architecture with advanced peripherals and low-power operation. Its wide operating voltage range, extensive memory options, and flexible packaging make it suitable for diverse applications in industrial, automotive, and consumer markets.