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Microchip Technology MCP1643-I/MS
- Part No.:
- MCP1643-I/MS
- Manufacturer:
- Microchip Technology
- Category:
- LED Drivers
- Package:
- 8-TSSOP, 8-MSOP (0.118", 3.00mm Width)
- Datasheet:
-
MCP1643-I/MS.pdf
- Description:
- IC LED DRV RGLTR PWM 550MA 8MSOP
- Quantity:
- Payment:
- Shipping:
Inventory:1,144
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Product details
Overview
MCP1643-I/MS from Microchip Technology is a synchronous step-up DC-DC converter optimized for constant-current LED driving in low-voltage battery-powered systems. It delivers up to 550 mA LED load current with 1.6A typical peak input current limit, operates down to 0.5V input after startup, features 120 mV feedback reference voltage, and integrates internal synchronous rectification and compensation. It is used in portable LED flashlights powered by one or two alkaline/NiMH cells.
For engineers reviewing the MCP1643-I/MS datasheet, MCP1643-I/MS pinout, MCP1643-I/MS application, or MCP1643-I/MS equivalent, key selection considerations include its 0.65V typical start-up voltage, true output disconnect during shutdown, 1 MHz fixed-frequency PWM operation, overvoltage protection clamping VOUT at 5.0V, and dual-package availability (MSOP-8 and 2x3 DFN-8).
Technical Context
The MCP1643-I/MS implements a fixed-frequency (1 MHz) peak-current-mode synchronous boost architecture with integrated N-channel high-side switch and P-channel synchronous rectifier. Its 120 mV VFB reference enables ultra-low-power current sensing via external RSET, minimizing sense resistor losses while maintaining tight LED current regulation across input voltages from 0.5V to 5.0V.
It employs adaptive slope compensation, internal soft-start (240 µs typical), and true output load disconnect-achieved by fully isolating VIN from VOUT via gate control of both switches when EN = GND. Overtemperature protection triggers at +150°C with +25°C hysteresis, and output overvoltage protection disables switching if VOUT exceeds 5.0V.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 0.5 V to 5.0 V - Enables operation from single-cell alkaline (0.9–1.6 V) or NiMH (0.9–1.4 V) and two-cell configurations without external LDO pre-regulation. |
| LED Load Current | Up to 550 mA - Supports high-brightness white or multi-color LED strings in portable lighting with minimal external components. |
| Feedback Reference Voltage | 120 mV ±15 mV - Reduces power loss in RSET to ~12 mW at 100 mA, improving efficiency and thermal performance vs. higher-VREF alternatives. |
| Switching Frequency | 1.0 MHz (0.85–1.15 MHz) - Allows use of compact 4.7 µH inductors and ceramic capacitors while minimizing audible noise in dimming applications. |
| Peak Input Current Limit | 1.6 A typical - Sets maximum inductor and switch stress; defines upper bound on deliverable LED current under low-VIN conditions. |
| Shutdown Quiescent Current | 1.2 µA typical - Extends battery life in standby mode; enables long-term storage in always-on motion-detect lamps. |
| Overvoltage Protection Threshold | 5.0 V typical - Safeguards downstream circuitry if LED opens or fails; prevents uncontrolled VOUT rise during open-load transients. |
| Thermal Shutdown Threshold | +150°C junction temperature - Protects against thermal runaway during sustained high-current or poor PCB heat sinking conditions. |
Pinout & Package
Package: MSOP-8 (MCP1643-I/MS). Exposed thermal pad (EP) must be connected to SGND/PGND on PCB for thermal management.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 EN | Enable logic input | Active-high enable; threshold is 75% of VIN - supports direct battery-sourced PWM dimming without level-shifting. |
| 2 VFB | Current-sense feedback node | Regulates voltage across RSET to 120 mV - sets LED current as ILED = 120 mV / RSET; requires short trace to minimize noise coupling. |
| 3 NC | No-connect terminal | Internally unconnected - must remain floating; no PCB trace or solder mask required. |
| 4 VOUT | Boost output power rail | High-current path to LED anode and output capacitor - connects to integrated P-channel switch source; requires low-ESR ceramic cap (4.7–20 µF). |
| 5 SW | Switch node | Connects to inductor and internal N-channel drain/P-channel source - carries up to 1.6 A peak current; must be routed with short, wide copper. |
| 6 PGND | Power ground return | Return path for high-current N-channel switch - separate from SGND to avoid noise injection into feedback loop. |
| 7 SGND | Signal ground reference | Return for VFB amplifier and error circuitry - must tie to PGND externally at single point near device to prevent ground loops. |
| 8 VIN | Input supply pin | Accepts 0.5–5.0 V input - requires local 4.7 µF X7R/X5R ceramic bypass capacitor placed adjacent to pin. |
Key Features
| Feature | Design Value |
|---|---|
| True Output Load Disconnect | EN = GND fully isolates VIN from VOUT by turning off both internal switches - eliminates battery drain and enables fast restart without output capacitor discharge. |
| Low Start-up Voltage | 0.65 V typical (25 mA LED load) - allows reliable ignition from deeply discharged alkaline or NiMH cells where other boost drivers fail to start. |
| Synchronous Rectification | Integrated P-channel rectifier replaces external Schottky diode - eliminates 0.3–0.5 V forward drop, increasing efficiency by ~5–10% at medium loads. |
| Internal Compensation | All loop compensation components embedded - removes need for external RC networks, reducing BOM count and layout sensitivity. |
| PWM Dimming Support | Linear LED current control via EN pin duty cycle - enables smooth brightness adjustment up to 1 kHz without flicker or color shift. |
| Overvoltage & Thermal Protection | Auto-recovering 5.0 V OVP and +150°C TSD with +25°C hysteresis - ensures robustness in open-circuit, over-temp, or short-circuit fault conditions. |
Applications
| LED Flashlight Systems | Rechargeable Headlamps |
|---|---|
|
Use Scenario: Portable handheld flashlight powered by two AA alkaline batteries with momentary ON/OFF and variable brightness. IC Role / Device Role / Timing Role: Constant-current LED driver regulating 350 mA through single white LED using RSET feedback; enables 0.65 V start-up from partially depleted cells. Use Value: Delivers full brightness even at end-of-life battery voltage (~0.9 V/cell), extending usable runtime by >25% versus non-low-VIN boost solutions. |
Use Scenario: Wearable headlamp for outdoor activity with motion-triggered illumination and USB-rechargeable NiMH battery pack. IC Role / Device Role / Timing Role: Synchronous boost controller providing 500 mA regulated current to dual parallel white LEDs; uses EN pin for PWM dimming synchronized to motion sensor output. Use Value: Achieves >85% efficiency at 1.2 V input, minimizing heat buildup in confined headband enclosure and enabling 8+ hours of continuous operation. |
| Wall-Mounted Motion-Sensing Lamps | LED Backlight for Low-Power Displays |
|
Use Scenario: Battery-operated indoor wall lamp activated by PIR sensor, requiring ultra-low quiescent current and instant turn-on. IC Role / Device Role / Timing Role: LED current regulator with true load disconnect - draws only 1.2 µA in shutdown, preserving 10-year shelf life of primary lithium cells. Use Value: Eliminates need for external load-switch FET; enables sub-100 ms wake-up from deep sleep due to retained VOUT charge during EN = GND. |
Use Scenario: Compact medical or industrial display with monochrome LCD requiring uniform edge-lit white LED backlight from coin cell. IC Role / Device Role / Timing Role: Fixed-frequency (1 MHz) boost converter driving 40 mA through series-connected red/green/yellow LEDs; leverages 120 mV VFB for precision current matching. Use Value: Maintains ±3% LED current accuracy across -40°C to +85°C ambient, ensuring consistent brightness and color point in unregulated environments. |
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 2.7V minimum input; 1.2 MHz switching; 28V OVP; no true load disconnect | Better suited for Li-ion (3.0–4.2V) inputs; lacks low-VIN start-up and isolation capability | Select when input is ≥2.7V and OVP margin >5V is required; avoid for alkaline/NiMH primary cells. |
| MAX1910EUT+T | 0.9V min input; 500 kHz switching; 1.25V VFB; external MOSFET required | Requires external high-side switch and compensation network; lower integration | Choose when design flexibility justifies added BOM and layout complexity; not drop-in compatible. |
Compared with TPS61061DRVR and MAX1910EUT+T, the MCP1643-I/MS uniquely combines sub-1V start-up, true output disconnect, and 120 mV VFB in a single MSOP-8 package-making it the only option capable of sustaining regulated LED current from 0.65V input while delivering <2 µA shutdown current.
Availability
MCP1643-I/MS is available at Aetrix Electronics and suitable for portable LED lighting, motion-activated wall lamps, and rechargeable headlamps requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.
Supply support for MCP1643-I/MS 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 company specializing in microcontrollers, analog devices, and power management ICs for industrial, automotive, and consumer applications.
The MCP1643-I/MS belongs to Microchip's LED driver product line, designed specifically for high-efficiency, low-input-voltage constant-current boosting in battery-powered portable lighting systems.
FAQ
What is the minimum input voltage required for MCP1643-I/MS to start up and regulate LED current?
The MCP1643-I/MS has a typical start-up voltage of 0.65 V with a 25 mA LED load. After start-up, it continues operating down to 0.5 V input. This ultra-low start-up threshold enables reliable operation from nearly depleted alkaline or NiMH cells. The actual start-up voltage may be lower if the output capacitor retains residual charge, but 0.65 V is the guaranteed minimum under specified test conditions per DS20005208A.
How does the MCP1643-I/MS achieve true output load disconnect during shutdown?
When EN is pulled low (GND), the MCP1643-I/MS turns off both its internal N-channel boost switch and P-channel synchronous rectifier, physically breaking the DC conduction path between VIN and VOUT. This eliminates leakage through the body diode of the P-channel switch, resulting in true isolation and only 1.2 µA typical shutdown current. This feature is confirmed in Section 4.2.4.1 of the MCP1643-I/MS datasheet.
Can the MCP1643-I/MS drive two white LEDs in series?
No, the MCP1643-I/MS cannot reliably drive two white LEDs in series. White LEDs typically require 2.7–3.2 V forward voltage each, totaling >5.4 V, exceeding the device's 5.0 V overvoltage protection threshold and maximum output voltage. However, it can drive two red/green/yellow LEDs in series (VF ≈ 1.8–2.4 V each) or multiple white LEDs in parallel with individual current-setting resistors, as documented in Section 5.5 of the MCP1643-I/MS datasheet.
What is the purpose of the 120 mV feedback reference voltage (VFB) in the MCP1643-I/MS?
The 120 mV VFB reference minimizes power dissipation in the external current-sense resistor (RSET), calculated as ILED × 0.12 V. For example, at 100 mA LED current, only 12 mW is lost in RSET-significantly reducing thermal load and improving overall efficiency compared to drivers with 0.6–1.25 V references. This low-VFB architecture is central to the MCP1643-I/MS design for battery-constrained applications.
Does the MCP1643-I/MS support PWM dimming, and what are the frequency limitations?
Yes, the MCP1643-I/MS supports linear PWM dimming via the EN pin. The LED current scales proportionally with EN duty cycle (Figure 2-8). Maximum dimming frequency is limited by the internal soft-start time of 240 µs (typical), making 1 kHz the practical upper limit. Lower frequencies (e.g., 400 Hz) are recommended for stable operation across temperature and load variations, as verified in the Typical Performance Curves of the MCP1643-I/MS datasheet.
MCP1643-I/MS Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- 8-TSSOP, 8-MSOP (0.118", 3.00mm Width)
- 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-MSOP
MCP1643-I/MS FAQ
1.How can I place an order for MCP1643-I/MS through Aetrix?
Please submit a Request for Quotation (RFQ) for MCP1643-I/MS 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/MS reliable?
The price and inventory of MCP1643-I/MS 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/MS is usually 5 days.
3.What payment methods are accepted for MCP1643-I/MS?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MCP1643-I/MS transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MCP1643-I/MS?
MCP1643-I/MS orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MCP1643-I/MS 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/MS?
For technical support, including MCP1643-I/MS datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MCP1643-I/MS requirements.
6.How does Aetrix verify that MCP1643-I/MS is sourced from the original manufacturer or authorized distributors?
All MCP1643-I/MS 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/MS meets industry standards.
7.What is the process for return or replacement of MCP1643-I/MS?
All MCP1643-I/MS units undergo pre-shipment inspection (PSI). If there is an issue with MCP1643-I/MS, 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/MS part is unused and in its original packaging.
Return procedure for MCP1643-I/MS:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
MCP1643-I/MS Tags
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BCR430UXTSA2
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BCR420UE6433HTMA1
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HV9910CLG-G
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