The MCP73831 battery charger IC is a compact linear charger for single-cell Li-Ion and Li-Polymer batteries. Engineers use it in USB-powered wearables and small electronics. It needs very few external parts, so it fits tight budgets and tight boards. This guide covers the specs, features, and design tips you need.
Key Takeaways
- The MCP73831 charges single-cell lithium batteries with almost no external parts.
- A single resistor sets the charge current, up to 500mA.
- Built-in thermal regulation protects the chip without extra components.
- Three voltage variants (4.20V, 4.35V, 4.40V) cover most lithium battery chemistries.
- Small SOT-23-5 and DFN packages suit wearables and compact IoT designs.
What Is the MCP73831 Battery Charger IC?
The MCP73831 battery charger IC is a linear charge management controller. It handles preconditioning, constant-current, and constant-voltage charging stages. The chip also monitors charge termination automatically. As a result, designers need very few external parts.
Core Function of the MCP73831 Linear Charger
This linear charger regulates current and voltage in one chip. It draws power directly from a USB port or wall adapter. Therefore, the design needs no external inductor. This keeps the circuit simple and low-cost.
Key Features of the MCP73831 Charger IC
The MCP73831 charger IC offers several practical design benefits. First, it supports programmable charge current. Second, it includes thermal regulation for safety. Third, it comes in small packages for space-constrained boards.
Programmable Charge Current on the MCP73831
A single resistor sets the charge current. This resistor connects to the PROG pin. For example, a lower resistance gives a higher charge current. The maximum programmable current reaches 500mA.
Thermal Regulation in the MCP73831
Thermal regulation protects the die during high-power charging. The IC reduces charge current if it overheats. This prevents damage during worst-case conditions. It also removes the need for extra thermal components.
MCP73831 Technical Specifications
The table below lists typical MCP73831 parameters.
| Parameter | Symbol | Range | Unit | Notes |
| Input voltage | VDD | 3.75–6.0 | V | USB or adapter input |
| Regulated output voltage | VREG | 4.20 / 4.35 / 4.40 | V | Set by device variant |
| Charge current | ICHG | 15–500 | mA | Set via PROG resistor |
| Voltage accuracy | — | ±0.75 | % | Over temperature range |
| Operating temperature | TA | -40 to +85 | °C | Industrial range |
These specs support most single-cell lithium batteries. However, always confirm your battery’s voltage requirement first. Choosing the correct VREG variant avoids overcharging risks.
MCP73831 Voltage and Current Ratings
Voltage ratings vary by ordering code. Common options include 4.20V, 4.35V, and 4.40V. In addition, current ratings scale with the PROG resistor value. This flexibility supports many battery chemistries.
MCP73831 Package Options
The MCP73831 ships in SOT-23-5 and 2×3 DFN packages. Both packages fit tight PCB layouts. So, the chip suits wearables and compact IoT modules.
Typical Applications for MCP73831 USB Charging
USB charging is the primary use case for this IC. It fits devices charged from a standard USB port. For instance, fitness trackers and Bluetooth headsets use it often. It also works well in portable medical devices.
MCP73831 Use in Wearables and Small Electronics
Wearables need small, efficient charging circuits. The MCP73831 battery charger IC fits this need well. Its small package saves board space. Also, a low external part count reduces total cost.
MCP73831 Use in Portable IoT Devices
Design Considerations for the MCP73831
Good layout and component choices matter for reliable charging. First, place the PROG resistor close to the pin. Second, use a low-ESR input capacitor. Finally, keep thermal pads connected to copper.
Setting MCP73831 Charge Current with One Resistor
PCB Layout Tips for the MCP73831
How Does the MCP73831 Compare to Similar Charger ICs?
Many linear charger ICs compete with the MCP73831. However, each option has a different feature set. Compare current ratings and package types carefully. This ensures the best fit for your design.
MCP73831 vs. MCP73833 Comparison
| Feature | MCP73831 | MCP73833 |
| Max charge current | 500mA | 1000mA |
| Package options | SOT-23-5, DFN | SOT-23-5, DFN, MSOP |
| Status output | Single pin | Single pin |
| Typical use case | Small wearables | Higher-capacity batteries |
For higher current needs, the MCP73833 is a better fit. For small, low-power devices, the MCP73831 remains a strong choice.
Frequently Asked Questions
How Do I Calculate the PROG Resistor Value for the MCP73831?
Use the datasheet formula relating resistance to charge current. This ensures accurate, safe charging levels for your design.
Does the MCP73831 Support Multiple Battery Voltages?
Yes. It ships in fixed 4.20V, 4.35V, and 4.40V versions. Choose the variant that matches your battery.
Is External Thermal Management Required for the MCP73831?
No. The chip includes built-in thermal regulation. This protects the IC during high-current charging.
What Is the Typical MCP73831 Charge Termination Method?
The IC monitors current tapering to detect a full charge. It then stops charging automatically.
Can the MCP73831 Charge Damaged or Swollen Batteries?
No. Never charge a damaged battery with any charger IC. Always inspect batteries carefully before charging.
Conclusion
The MCP73831 battery charger IC is a simple, reliable choice. It fits small, USB-powered lithium battery designs well. The chip needs few external parts and offers built-in safety features. For most low-power wearables and IoT modules, it remains a strong first choice.
Find What You Need on LCSC
Finding the right battery charger IC is easy on LCSC. LCSC stocks a wide range of charging ICs, from single-cell linear chargers to higher-current solutions. You can filter by specification, compare prices, and order in any quantity. Start browsing today.
