Overview
The STM1815TWX7F is a low power reset circuit produced by STMicroelectronics. It is designed to monitor power supplies for microcontrollers, ensuring reliable operation by asserting a reset signal when the supply voltage drops below a preset threshold. This device is part of the STM181x family, which offers various output configurations and features tailored for different applications.
Key Specifications
| Parameter | Value | Description |
|---|---|---|
| Supply Voltage Monitoring | 3 V, 3.3 V, 5 V | Precision monitoring of supply voltages |
| Output Configuration | Active-low, push-pull | RST output configuration for STM1815TWX7F |
| Reset Pulse Width | 100 ms (min.) | Minimum duration the reset signal is asserted after VCC rises above the reset threshold |
| Supply Current | 4 µA (typ.) | Typical supply current consumption |
| Reset Thresholds | 2.55 V, 2.88 V, 3.06 V, 4.37 V, 4.62 V (typ.) | Factory-trimmed reset thresholds |
| Operating Temperature | –40 °C to 105 °C | Temperature range for guaranteed operation |
| Package | SOT23-3 | Package type for the device |
| Reset Threshold Accuracy | ± 2.5% (–40 °C to 105 °C) | Accuracy of the reset threshold over the operating temperature range |
Key Features
- Precision Voltage Monitoring: Monitors 3 V, 3.3 V, and 5 V supply voltages with high accuracy.
- Low Power Consumption: Typical supply current of 4 µA, making it suitable for portable and low-power applications.
- Multiple Output Configurations: Available in push-pull active-low, push-pull active-high, and open-drain active-low configurations.
- Reset Pulse Width: Ensures the reset signal is asserted for a minimum of 100 ms after VCC rises above the reset threshold.
- Power Supply Transient Immunity: Designed to ignore fast transients on VCC, enhancing reliability.
- Manual Reset Detect: For certain models, features a debounced manual reset capability, ideal for use with mechanical switches.
- Compact Packaging: Available in the space-saving 3-pin SOT23 package.
Applications
The STM1815TWX7F is ideal for use in various applications where reliable power supply monitoring is crucial, such as:
- Portable Equipment: Due to its low power consumption and compact packaging.
- Microcontroller Systems: Ensures the microcontroller starts in a known state during power-up, power-down, and brownout conditions.
- Embedded Systems: Provides a reliable reset mechanism to prevent code-execution errors.
- Industrial and Automotive Systems: Operates over a wide temperature range, making it suitable for harsh environments.
Q & A
- What is the primary function of the STM1815TWX7F?
The primary function is to monitor the power supply voltage and assert a reset signal to the microcontroller if the voltage drops below a preset threshold.
- What are the supported supply voltages for the STM1815TWX7F?
The device supports precision monitoring of 3 V, 3.3 V, and 5 V supply voltages.
- What is the typical supply current of the STM1815TWX7F?
The typical supply current is 4 µA.
- What is the minimum reset pulse width for the STM1815TWX7F?
The minimum reset pulse width is 100 ms.
- Does the STM1815TWX7F have manual reset capability?
No, the STM1815TWX7F does not have manual reset capability. This feature is available in models like STM1813 and STM1818.
- What is the operating temperature range for the STM1815TWX7F?
The operating temperature range is –40 °C to 105 °C.
- In what package is the STM1815TWX7F available?
The device is available in the 3-pin SOT23 package.
- How accurate is the reset threshold of the STM1815TWX7F?
The reset threshold accuracy is ± 2.5% over the operating temperature range.
- Is the STM1815TWX7F immune to power supply transients?
Yes, the device is designed to ignore fast transients on VCC.
- Can the STM1815TWX7F be used with bidirectional microcontroller reset pins?
Yes, especially models with open-drain outputs like STM1811 and STM1816, which interface easily with bidirectional reset pins.
