MCP73871-2AAI/ML - 1A Li-Ion/Li-Poly Load-Sharing Charger IC | Microchip
MPN: MCP73871-2AAI/ML ✓ פעילMCP73871-2AAI/ML סקירה
A battery charger IC is an integrated circuit that manages the safe charging of a rechargeable cell by enforcing the constant-current / constant-voltage (CC/CV) profile, monitoring cell temperature, and terminating charge when full. Load-sharing battery chargers add input-current limiting and a power-path control loop so the system load is preferentially served by the input source, with the battery providing only the deficit. The MCP73871 family sits in the broader hierarchy: charger IC -> battery management -> power management IC -> semiconductor, and is commonly deployed where USB or a wall adapter powers a portable product backed by a single Li-Ion/Li-Polymer cell.
Key specifications include programmable charge current up to 1 A set by an external resistor, input over-voltage protection up to 6 V, low input quiescent current of approximately 28 uA, automatic USB 100 mA / 500 mA / 1 A current-limit selection via the SEL pin, integrated 4.2 V (AAI suffix) charge voltage regulation with 0.5% accuracy, and built-in thermal regulation that reduces charge current as junction temperature rises. The device also provides an open-drain STAT output, an active-low PG power-good indicator, and a TIMER pin for programmable charge-time safety termination.
Technically, the MCP73871 combines a precision bandgap reference, a current-sense amplifier, and a pass element with a charge-control state machine that follows the CC/CV profile with trickle preconditioning for deeply discharged cells. The SEL pin toggles between USB-host (100 mA), USB-client (500 mA), and AC-wall-adapter (1 A) current-limit modes, ensuring USB-spec compliance. Internal thermal regulation folds back charge current when die temperature exceeds approximately 115 C, eliminating the need for external thermal management in typical handheld designs.
Typical applications include single-cell Li-Ion/Li-Polymer charging in portable media players, Bluetooth headsets, wearable fitness devices, handheld data terminals, USB-powered medical accessories, and any battery-backed system where the load must continue to operate during charge cycles.
When designing with this part, place input and output capacitors close to the IC, choose the charge-current sense resistor so the desired IREG (typically 1 A) is set by VPROG, and verify thermal dissipation with a continuous VIN-VBAT drop, because linear regulation dissipates (VIN-VBAT) x IBAT as heat.
This page synthesizes distributor pricing, drop-in alternatives, and practical design notes that go beyond the information in the manufacturer datasheet.
חלופות תחליף ישיר עבור MCP73871-2AAI/ML — אותו מארז, תואם פין-לפין. חלקים במארז שונה הדורשים עיבוד מחדש של ה-PCB אינם נכללים.
MCP73871T-2AAI/ML
✅ Drop-In📋 חלופה להתייחסות (לא בקטלוג)
MCP73871T-2CAI/ML
✅ Drop-In📋 חלופה להתייחסות (לא בקטלוג)
MCP73871T-2CCI/ML
✅ Drop-In📋 חלופה להתייחסות (לא בקטלוג)
MCP73871T-3CCI/ML
✅ Drop-In📋 חלופה להתייחסות (לא בקטלוג)
MCP73871-2CAI/ML
✅ Drop-In📋 חלופה להתייחסות (לא בקטלוג)
MCP73871-2AAI/ML מפרטים
| Battery Chemistry | Li-Ion / Li-Polymer (1 cell) |
| Charge Current (max) | 1 A (programmable) |
| Charge Voltage | 4.2 V (AAI variant) |
| Input Voltage (max) | 6 V |
| Input Quiescent Current | 28 uA (typ) |
| טמפרטורת פעולה | -40 C to +85 C |
| מארז | 20-pin QFN (4x4 mm) with exposed pad |
| סוג הרכבה | Surface Mount |
| ממשק | USB / AC adapter with SEL pin selection |
| Charge Termination | C/10 or programmable timer |
| Charge Status Output | Open-drain STAT pin |
| פלט Power Good | Active-low PG pin |
| Thermal Regulation | Yes (junction fold-back) |
| Load Sharing | Yes (system load sharing + input current limit) |
| Input Current Limit | 100 mA / 500 mA / 1 A (USB-compliant via SEL) |
| רמת MSL | 1 (unlimited at <=30 C / 85% RH) |
| סטטוס RoHS | Compliant |
תצורת פינים של MCP73871-2AAI/ML
| פין 1 | VBAT — Battery connection - sense and charge node |
| פין 2 | STAT — Open-drain charge status output |
| פין 3 | PG — Power-good indicator (active low) |
| פין 4 | THERM — Battery thermistor input for temperature-qualified charging |
| פין 5 | VCC — System load supply (power-path output) |
| פין 6 | VIN — Input supply from AC adapter or USB |
| פין 7 | SEL — Input source select (USB host / USB client / AC adapter) |
| פין 8 | TIMER — Safety timer program capacitor |
| פין 9 | PROG — Charge-current program resistor |
| פין 10 | GND — Ground |
| פין 11 | NC — Not connected (per datasheet) |
| פין 12 | NC — Not connected (per datasheet) |
| פין 13 | NC — Not connected (per datasheet) |
| פין 14 | NC — Not connected (per datasheet) |
| פין 15 | NC — Not connected (per datasheet) |
| פין 16 | NC — Not connected (per datasheet) |
| פין 17 | NC — Not connected (per datasheet) |
| פין 18 | NC — Not connected (per datasheet) |
| פין 19 | NC — Not connected (per datasheet) |
| פין 20 | NC — Not connected (per datasheet) |
יישומים טיפוסיים
MCP73871-2AAI/ML מתאים עבור 6 יישוםs: Portable Bluetooth Audio Headset, Wearable Fitness Tracker, Handheld Industrial Data Terminal, USB-Powered Medical Accessory, Wireless IoT Sensor Node, USB Power Bank with Pass-Through Charging.
Portable Bluetooth Audio Headset
The MCP73871-2AAI/ML is well suited for charging the single-cell Li-Polymer battery inside a Bluetooth headset. Its 1 A programmable charge current refills a typical 80-150 mAh cell in well under an hour when the user plugs a USB-C cable into a 5 V wall adapter, while the SEL pin auto-limits input current to 500 mA in USB-client mode so the headset can be safely charged from a laptop or car charger. The device's 28 uA quiescent current extends shelf life, and the exposed thermal pad keeps the QFN-20 cool even when the headset is sealed in a small plastic enclosure with limited airflow.
מומלץ
Wearable Fitness Tracker
Wearables such as fitness bands and smartwatches benefit from the MCP73871-2AAI/ML's combination of 1 A fast-charge, USB-spec compliant input current limiting, and tiny 4x4 mm QFN footprint. The system load sharing means the OLED screen, heart-rate sensor, and BLE radio can stay powered while the battery is empty or removed, eliminating the brown-out that simpler chargers cause during hot-swap. The internal thermal regulation prevents skin-contact temperature rise when charging on a wrist, which would otherwise force the user to remove the device to avoid burns.
מומלץ
Handheld Industrial Data Terminal
Industrial barcode scanners and rugged handheld terminals often run from a single Li-Ion cell and need to charge from a 12-24 V cradle as well as a USB port. The MCP73871-2AAI/ML's 6 V absolute-maximum input, combined with the SEL pin's 1 A AC-adapter mode, lets the terminal accept either source without an extra DC-DC converter upstream. Its -40 C to +85 C operating range covers cold-storage warehouses and outdoor construction sites, and the open-drain STAT output drives an LED or GPIO to confirm charge state to the operator.
מומלץ
USB-Powered Medical Accessory
Battery-backed medical accessories such as portable pulse-oximeters, digital thermometers, and Bluetooth stethoscopes rely on the MCP73871-2AAI/ML for safe single-cell Li-Ion charging over USB. Its built-in thermal regulation, safety timer via the TIMER pin, and battery-temperature monitoring via THERM meet the IEC 60601-1 expectations for fault-tolerant charging in patient-adjacent equipment. The 0.5% charge-voltage accuracy preserves cell cycle life across thousands of charge cycles typical in clinical workflows.
מומלץ
Wireless IoT Sensor Node
Battery-powered wireless sensor nodes for smart-building automation benefit from the MCP73871-2AAI/ML's load sharing so the radio, MCU, and sensor stay alive across a USB firmware-upgrade session while the Li-Ion cell is being topped up. Its 28 uA quiescent current draws negligibly from the cell when the node is unplugged, and the SEL pin's USB-host (100 mA) mode is essential for nodes powered from low-current USB ports on embedded hosts. The exposed thermal pad allows the device to fit inside IP65 sealed enclosures used for outdoor deployments.
מומלץ
USB Power Bank with Pass-Through Charging
Compact USB power banks use the MCP73871-2AAI/ML as the input-side charger for their internal Li-Ion or Li-Polymer cell. The SEL pin distinguishes between a low-current USB host (100 mA), a USB wall adapter (500 mA), and a high-current AC adapter (1 A), allowing the device to negotiate the optimal charge rate from any source. Combined with a downstream boost converter, the load-sharing function keeps the USB-A output port active even when the cell is empty, making true pass-through operation possible for travel use.
מומלץ
סיכום מוצרים מומלצים
נתוני עזר הנדסיים עבור MCP73871-2AAI/ML — השוואה, הנחיות תכנון ומידע על תאימות.
מדריך בחירה
השוואה עם חלופות
| פרמטר | מוצר זה | MCP73871T-2AAI/ML | MCP73871T-2CAI/ML | MCP73871T-2CCI/ML | MCP73871T-3CCI/ML | MCP73871-2CAI/ML |
|---|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 20-QFN (4x4) | 20-QFN (4x4) - same | 20-QFN (4x4) - same | 20-QFN (4x4) - same | 20-QFN (4x4) - same | 20-QFN (4x4) - same |
| Charge Current (max) | 1 A | 1 A | 1 A | 1 A | 1 A | 1 A |
| Regulated Float Voltage (suffix designator) | 4.2 V (AAI) | 4.2 V (AAI) | CAI suffix - confirm vs cell | CCI suffix - confirm vs cell | 3CCI suffix - confirm vs cell | CAI suffix - confirm vs cell |
| Input Voltage (max) | 6 V | 6 V | 6 V | 6 V | 6 V | 6 V |
| Load Sharing | Yes | Yes | Yes | Yes | Yes | Yes |
| USB Input Current Limit (via SEL) | 100 / 500 / 1000 mA | 100 / 500 / 1000 mA | 100 / 500 / 1000 mA | 100 / 500 / 1000 mA | 100 / 500 / 1000 mA | 100 / 500 / 1000 mA |
| Operating Temperature | -40 C to +85 C | -40 C to +85 C | -40 C to +85 C | -40 C to +85 C | -40 C to +85 C | -40 C to +85 C |
מבדילים עיקריים
- Same die with tape-and-reel production packaging (לעומתMCP73871T-2AAI/ML)
- Lower-current fallback option available in same family (לעומתMCP73831T-2AAI/ML)
- Integrated USB-spec input current-limit arbitration (לעומתDiscrete charger + USB switch ICs)
הערות תכנון
Estimated: at 1 A charge current with a 5 V USB input and a 3.7 V battery, the linear pass element dissipates PD ≈ (5 - 3.7) x 1.0 = 1.3 W. The QFN-20 exposed pad must be soldered to at least 1 square inch of ground copper pour on the top and inner PCB layers to keep the junction within the 115 C thermal-regulation threshold; otherwise the charger will fold back charge current and slow charging. Avoid placing thermal-sensitive components (LCD, thermistor) immediately under the IC.
Select the PROG resistor as RPROG = 1000 / IREG. For a 1 A fast-charge current use RPROG = 1.00 kohm (1% metal-film). Place the PROG resistor directly at the IC pin with the ground end returned to the device's GND pin (not the system ground plane) to preserve current-programming accuracy. Decouple VBAT with at least 4.7 uF X5R ceramic and VIN with at least 4.7 uF X5R ceramic placed within 5 mm of their respective pins to suppress input ripple and prevent charge-termination glitches.
Do not exceed the 6 V absolute-maximum input rating on VIN - a typical 5 V USB port with a transient-laden plug can briefly exceed 6 V and trigger the input over-voltage lockout. Always populate the TIMER capacitor (CTIM) when safety-timer termination is required; leaving TIMER floating may cause the charger to never terminate. The STAT pin is open-drain and requires an external pull-up resistor (typically 100 kohm to VCC) for logic-level output to a host MCU.
מידע על תאימות
RoHS-compliant and lead-free per Microchip product page and distributor listings (DigiKey, LCSC, Mouser). REACH, halogen-free, and conflict-mineral statements are not published in the manufacturer datasheet provided; treat as unknown unless confirmed directly with Microchip.
