3-Pin Microprocessor Power Supply Supervisors # CAT810JTBIGT3 Technical Documentation
## 1. Application Scenarios
### Typical Use Cases
The CAT810JTBIGT3 is a microprocessor (μP) supervisory circuit primarily employed in embedded systems requiring reliable power monitoring and reset control. Key applications include:
- Power-On Reset Generation : Provides a 140ms minimum reset pulse during power-up sequences
- Brown-Out Detection : Monitors VCC voltage and asserts reset when voltage drops below threshold
- Manual Reset Control : Supports external push-button reset functionality via MR pin
- Battery-Powered Systems : Low quiescent current (5μA typical) makes it suitable for portable devices
### Industry Applications
- Industrial Automation : PLCs, motor controllers, and industrial PCs requiring robust reset functionality
- Consumer Electronics : Smart home devices, gaming consoles, and set-top boxes
- Automotive Systems : Infotainment systems, telematics, and body control modules (operating temperature -40°C to +85°C)
- Medical Devices : Patient monitoring equipment and portable diagnostic tools
- Communications Equipment : Routers, switches, and base station controllers
### Practical Advantages and Limitations
Advantages:
- High Accuracy : ±1.5% reset voltage threshold accuracy ensures reliable operation
- Low Power Consumption : 5μA typical supply current extends battery life
- Small Form Factor : SOT-23-5 package saves board space
- Wide Voltage Range : Operates from 1.0V to 5.5V VCC
- No External Components : Requires minimal external components for basic operation
Limitations:
- Fixed Timeout Period : 140ms reset timeout may not be adjustable for all applications
- Limited Drive Capability : RESET output can sink 12mA maximum
- Temperature Constraints : Not suitable for extreme environments beyond specified -40°C to +85°C range
## 2. Design Considerations
### Common Design Pitfalls and Solutions
Pitfall 1: Inadequate Bypass Capacitance
- Issue : Insufficient decoupling causes false resets due to power supply noise
- Solution : Place 0.1μF ceramic capacitor within 10mm of VCC pin, with additional bulk capacitance (10μF) for noisy environments
Pitfall 2: Improper MR Pin Handling
- Issue : Floating MR pin susceptible to noise-induced resets
- Solution : Connect to VCC through 10kΩ resistor if manual reset not required, or implement proper debouncing circuit
Pitfall 3: RESET Line Loading
- Issue : Excessive capacitive loading on RESET output causes slow rise times
- Solution : Limit trace length and avoid connecting multiple high-capacitance loads directly
### Compatibility Issues with Other Components
Microprocessor Interfaces:
- Compatible with 3.3V and 5V logic families
- Ensure RESET output voltage levels match μP requirements
- Watchdog timer compatibility varies by μP architecture
Power Supply Considerations:
- Works with LDO regulators and switching power supplies
- Monitor power supply ramp rates; minimum 1V/ms recommended
- Consider voltage supervisor response time (1μs typical) for fast transients
### PCB Layout Recommendations
Power Distribution:
- Use star-point grounding for analog and digital sections
- Route VCC trace directly from power supply bypass capacitor
- Maintain continuous ground plane beneath device
Signal Routing:
- Keep RESET trace short and direct to μP reset pin
- Route MR trace away from noisy digital signals
- Implement guard rings around analog inputs if in high-noise environment
Thermal Management:
- Provide adequate copper pour for heat dissipation
- Avoid placing near heat-generating components
