CN810S

The CN803/809/810 series are microprocessor reset circuits designed to monitor power supply or battery voltage. These devices require no external components, improving system reliability and reducing system cost. The series asserts a reset signal when the monitored supply voltage falls below the preset reset threshold. When the supply voltage rises above the reset threshold, the reset signal remains asserted for a minimum of 140ms. CN809/810 provide CMOS reset outputs, while CN803 provides an open-drain output. CN803 and CN809 are active-low reset outputs; CN810 is an active-high reset output. The design ensures that brief power supply glitches do not affect the reset output. Guaranteed valid output is maintained down to a supply voltage of 1.15V over the full temperature range. All devices in this series are available in a 3-pin SOT23 package. The CN803/809/810 series are primarily used to monitor the power supplies of microprocessors, microcontrollers, memories, and other digital circuits, providing reset signals during power-up, power-down, or whenever the supply voltage falls below the reset threshold. This ensures operation in a known state and prevents execution of erroneous code. The device integrates a voltage comparator, low-power voltage reference, resistor divider network, output delay circuit, and output driver circuit. The CN803/809/810 series asserts a reset signal when the supply voltage falls below the reset threshold. After the supply voltage rises above the sum of the reset threshold and reset threshold hysteresis, the reset output remains asserted for a minimum of 140ms. CN809/810 provide CMOS outputs, while CN803 provides an open-drain output. CN803/809 provide active-low reset outputs, while CN810 provides an active-high reset output. The design ensures that brief power supply glitches do not affect the reset output. Guaranteed valid output is maintained down to a supply voltage of 1.15V over the full operating temperature range.

Applications

• Computers
• Microcontrollers
• Smart meters
• Portable or battery-powered devices

Key features

• Precision reset threshold: ±2.5%
• Two reset output options: -CMOS output (CN809/CN810) -Open-drain output (CN803)
• Minimum reset pulse width: 140ms
• Low operating current: 3.2μA typical at 3V
• Reset signal remains reliable down to 1.15V supply voltage
• Power supply glitch filtering
• Operating temperature range: -40°C to +85°C
• SOT23-3 package