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Microchip Technology MCP1643-I/MC
- Part No.:
- MCP1643-I/MC
- Manufacturer:
- Microchip Technology
- Category:
- LED Drivers
- Package:
- 8-VFDFN Exposed Pad
- Datasheet:
-
MCP1643-I/MC.pdf
- Description:
- IC LED DRVR RGLTR PWM 550MA 8DFN
- Quantity:
- Payment:
- Shipping:
Inventory:228
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Product details
Overview
MCP1643-I/MC from Microchip Technology is a synchronous step-up DC-DC converter optimized for constant-current LED driving from single/dual-cell alkaline or NiMH/NiCd batteries. It delivers up to 550 mA LED load current with 1 MHz fixed-frequency PWM operation, 120 mV feedback reference voltage, and true output disconnect during shutdown - enabling flashlight, headlamp, and motion-sensing wall lamp applications.
For engineers reviewing the MCP1643-I/MC datasheet, MCP1643-I/MC pinout, MCP1643-I/MC application, or MCP1643-I/MC equivalent, key selection criteria include low-startup voltage (0.65 V), integrated synchronous rectification, overvoltage protection clamping at 5.0 V, thermal shutdown at +150°C, and dual-package availability (MSOP-8 and 2x3 DFN-8) for space-constrained portable lighting designs.
Technical Context
The MCP1643-I/MC implements peak-current-mode control with adaptive slope compensation and an internal 120 mV error amplifier reference. Its architecture integrates both N-channel boost switch (RDS(ON) = 0.2 Ω) and P-channel synchronous rectifier (RDS(ON) = 0.4 Ω), eliminating external diode losses and enabling >90% efficiency at 100–300 mA LED loads.
Startup logic enables operation from 0.65 V (25 mA LED), sustaining regulation down to 0.5 V input; overvoltage protection monitors VOUT and halts switching if >5.0 V (e.g., open-load LED failure), while thermal shutdown activates at +150°C with +25°C hysteresis to prevent damage under sustained overload.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 0.5 V to 5.0 V - supports direct operation from depleted single-cell alkaline (0.5 V) and two-cell NiMH (2.4 V), no UVLO circuitry required. |
| Output Current Capability | Up to 550 mA - set via external RSET; regulated by 120 mV VFB, minimizing sense resistor power loss (e.g., 12 mW at 100 mA). |
| Switching Frequency | 1.0 MHz (±15%) - enables use of compact 4.7 µH inductors and reduces EMI filtering requirements. |
| Peak Input Current Limit | 1.6 A typical - protects internal switches during startup and transient overloads without external current sensing. |
| Feedback Reference Voltage | 120 mV (105–135 mV) - allows ultra-low-loss current sensing; sets ILED = 120 mV / RSET. |
| Shutdown Quiescent Current | 1.2 µA typical - ensures battery longevity in standby; includes true output disconnect (no DC path from VIN to VOUT). |
| Thermal Shutdown Threshold | +150°C with +25°C hysteresis - self-recovering protection against PCB-level thermal overload in enclosed fixtures. |
Pinout & Package
Available in MSOP-8 and 2x3 DFN-8 packages, both with exposed thermal pad (EP) requiring PCB connection to ground for thermal performance. The DFN variant offers θJA = 68°C/W vs. MSOP's 211°C/W.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| EN | Enable control input | Logic-high (>75% VIN) enables regulation; logic-low (<20% VIN) forces shutdown with true load disconnect and 1.2 µA IQ. |
| VFB | Feedback voltage input | Regulates voltage across RSET to 120 mV; connects to RSET cathode node - critical for noise immunity and layout. |
| NC | No-connect terminal | Internally unconnected; must be left floating or tied to GND per layout best practice - no electrical function. |
| VOUT | Boost output power rail | Delivers regulated LED current; requires 4.7–20 µF ceramic capacitor; connects to LED anode and RSET top node. |
| SW | Switch node | Connects to inductor; carries up to 1.6 A peak current; internal junction of N-ch boost switch drain and P-ch rectifier source. |
| PGND | Power ground return | High-current return path for N-channel switch; must be short-traced to CIN and inductor ground to minimize noise and voltage spikes. |
| SGND | Signal ground reference | Low-noise return for VFB and error amplifier; externally connected to PGND at single point near device to avoid ground loops. |
| VIN | Input supply voltage | Accepts 0.5–5.0 V; requires ≥4.7 µF local X5R/X7R bypass capacitor; supplies start-up bias until VOUT exceeds VIN. |
Key Features
| Feature | Design Value |
|---|---|
| Low-startup voltage operation | 0.65 V typical (25 mA LED) - enables usable runtime from deeply discharged alkaline cells where conventional boost ICs fail to start. |
| Synchronous rectification | Integrated P-channel MOSFET replaces lossy Schottky diode - eliminates ~0.3 V forward drop, raising efficiency by 5–10% at 200–500 mA loads. |
| True output disconnect | EN = GND removes all DC paths between VIN and VOUT - prevents battery drain through LED leakage or output capacitor discharge. |
| Internal soft-start | 240 µs typical - limits inrush current during enable, preventing input voltage sag and LED flash-on transients in portable systems. |
| Overvoltage protection | 5.0 V clamp on VOUT - disables switching if LED opens or fails, protecting downstream components from unregulated high-voltage stress. |
Applications
| Flashlight Power Management | Headlamp Constant-Current Drive |
|---|---|
Use Scenario: Rechargeable LED flashlight powered by two NiMH cells (2.4 V nominal) with variable-brightness PWM dimming. IC Role / Device Role / Timing Role: Synchronous boost regulator providing constant-current drive to white LED string; EN pin accepts 400 Hz PWM for linear brightness control. Use Value: Delivers stable 350 mA LED current down to 0.9 V input, extending usable battery life by 25% versus non-synchronous alternatives. |
Use Scenario: Compact headlamp using single alkaline cell (1.5 V) with motion-triggered illumination and auto-shutoff. IC Role / Device Role / Timing Role: Low-voltage LED driver enabling operation from fresh to fully depleted battery (0.65–1.5 V); true disconnect preserves battery during idle. Use Value: Starts reliably at 0.65 V and sustains 100 mA LED current until 0.5 V, delivering 3× longer runtime than 1.0 V minimum-start competitors. |
| Wall-Mount Motion-Sensing Lamp | Rechargeable Emergency Lighting |
Use Scenario: Battery-backed wall lamp with PIR sensor triggering LED illumination only when motion is detected. IC Role / Device Role / Timing Role: High-efficiency boost controller powering red/green/yellow LED array; OVP prevents overvoltage damage if sensor wiring disconnects. Use Value: Achieves >92% efficiency at 200 mA, reducing heat generation in sealed enclosures and enabling 12+ hour runtime on AA cells. |
Use Scenario: Emergency exit sign using NiCd battery backup with automatic LED activation during AC power loss. IC Role / Device Role / Timing Role: Constant-current regulator maintaining consistent LED brightness across full battery discharge curve (1.2–0.5 V). Use Value: Maintains ±5% LED current regulation from 1.2 V to 0.5 V input, ensuring uniform luminance and compliance with safety lighting standards. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar LED constant-current boost applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TPS61061DRVR | Higher 2.7 V min startup; 400 mA max ILED; no true output disconnect; 1.2 MHz switching. | Limited to higher-VIN systems (≥2.7 V); unsuitable for single-cell alkaline below 1.0 V. | Select only for 2-cell Li-ion or regulated 3.3 V input systems requiring tighter ILED accuracy (±3%). |
| MAX1910EUT+T | 0.9 V min startup; 350 mA max ILED; external diode rectification; no OVP; 1.0 MHz switching. | Lower efficiency due to diode loss; requires external overvoltage clamping for LED protection. | Consider for cost-sensitive designs where 5–8% lower efficiency and added BOM count are acceptable trade-offs. |
Compared with TPS61061DRVR and MAX1910EUT+T, the MCP1643-I/MC uniquely supports sub-1.0 V startup, integrates synchronous rectification and OVP, and provides true output disconnect - making it the only option qualified for single-cell alkaline flashlight and headlamp designs demanding maximum runtime and safety.
Availability
MCP1643-I/MC is available at Aetrix Electronics and suitable for portable LED lighting, motion-sensing wall lamps, and rechargeable emergency lighting requiring stable component supply across long production cycles and seasonal demand spikes.
Supply support for MCP1643-I/MC includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.
Manufacturer
Microchip Technology is a U.S.-based semiconductor manufacturer specializing in microcontrollers, analog devices, and power management ICs for embedded and industrial applications.
The MCP1643-I/MC belongs to Microchip's LED driver product line, designed specifically for battery-powered portable lighting with ultra-low-voltage operation, high efficiency, and integrated protection features.
FAQ
What is the minimum input voltage required for MCP1643-I/MC to start regulating LED current?
The MCP1643-I/MC starts regulating LED current at 0.65 V typical (25 mA load) with a fully discharged output capacitor. After startup, it continues regulation down to 0.5 V input. This capability enables full utilization of single-cell alkaline batteries beyond the 0.9–1.0 V cutoff of most competing boost drivers, directly extending flashlight runtime.
How does the MCP1643-I/MC achieve true output disconnect during shutdown?
The MCP1643-I/MC achieves true output disconnect by turning off both its internal N-channel boost switch and P-channel synchronous rectifier when EN = GND. This breaks all DC conduction paths between VIN and VOUT, isolating the battery from the LED and output capacitor. As a result, MCP1643-I/MC draws only 1.2 µA quiescent current and prevents battery drain through LED leakage or capacitor self-discharge.
Can the MCP1643-I/MC drive two white LEDs in series?
No, the MCP1643-I/MC cannot reliably drive two white LEDs in series. With a typical forward voltage of 2.7–3.2 V per white LED, two in series require 5.4–6.4 V, exceeding the MCP1643-I/MC's 5.0 V overvoltage protection threshold and causing immediate shutdown. It supports one white LED or two red/green/yellow LEDs (VF ≈ 1.8–2.4 V each) in series, as confirmed in the datasheet's Typical Applications section.
What is the role of the 120 mV feedback reference voltage (VFB) in MCP1643-I/MC operation?
The 120 mV VFB reference enables precise, low-loss LED current regulation: ILED = 120 mV / RSET. By setting such a low reference, power dissipation in RSET remains minimal (e.g., 12 mW at 100 mA), preserving efficiency and reducing thermal stress. This value is trimmed and specified from 105–135 mV over temperature, ensuring stable current regulation across -40°C to +85°C ambient.
How does the MCP1643-I/MC handle overvoltage conditions, and what triggers its protection?
The MCP1643-I/MC monitors VOUT continuously and disables switching if voltage exceeds 5.0 V typical - a condition that occurs during LED open-circuit failure or accidental disconnection. Protection is implemented via internal comparator circuitry; once triggered, the device halts switching and periodically rechecks VOUT. This prevents destructive overvoltage stress on the LED and output capacitor, though external Zener clamping between VOUT and VFB is recommended for full LED protection.
MCP1643-I/MC Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- 8-VFDFN Exposed Pad
- Packaging:
- Tube
- Product Status:
- Active
- Type:
- DC DC Regulator
- Topology:
- Step-Up (Boost)
- Internal Switch(s):
- Yes
- Number of Outputs:
- 1
- Voltage - Supply (Min):
- 0.5V
- Voltage - Supply (Max):
- 5V
- Voltage - Output:
- 5V
- Current - Output / Channel:
- 550mA
- Frequency:
- 1MHz
- Dimming:
- PWM
- Applications:
- Backlight
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-DFN (2x3)
MCP1643-I/MC FAQ
1.How can I place an order for MCP1643-I/MC through Aetrix?
Please submit a Request for Quotation (RFQ) for MCP1643-I/MC on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for MCP1643-I/MC reliable?
The price and inventory of MCP1643-I/MC are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MCP1643-I/MC is usually 5 days.
3.What payment methods are accepted for MCP1643-I/MC?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MCP1643-I/MC transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MCP1643-I/MC?
MCP1643-I/MC orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MCP1643-I/MC order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for MCP1643-I/MC?
For technical support, including MCP1643-I/MC datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MCP1643-I/MC requirements.
6.How does Aetrix verify that MCP1643-I/MC is sourced from the original manufacturer or authorized distributors?
All MCP1643-I/MC products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that MCP1643-I/MC meets industry standards.
7.What is the process for return or replacement of MCP1643-I/MC?
All MCP1643-I/MC units undergo pre-shipment inspection (PSI). If there is an issue with MCP1643-I/MC, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The MCP1643-I/MC part is unused and in its original packaging.
Return procedure for MCP1643-I/MC:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
MCP1643-I/MC Tags
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BCR402RE6327HTSA1
Infineon Technologies
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BCR430UXTSA2
Infineon Technologies
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BCR420UE6433HTMA1
Infineon Technologies
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BCR420UE6327HTSA1
Infineon Technologies
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BCR421UE6327HTSA1
Infineon Technologies
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LYT1604D-TL
Power Integrations
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HV9910CLG-G
Microchip Technology
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CL2N8-G
Microchip Technology
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BCR420UW6-7
Diodes Incorporated
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BCR421UW6-7
Diodes Incorporated
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BCR420UFD-7
Diodes Incorporated
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BCR421UFD-7
Diodes Incorporated
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