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Microchip Technology MCP1643T-I/MC
- Part No.:
- MCP1643T-I/MC
- Manufacturer:
- Microchip Technology
- Category:
- LED Drivers
- Package:
- 8-VFDFN Exposed Pad
- Datasheet:
-
MCP1643T-I/MC.pdf
- Description:
- IC LED DRVR RGLTR PWM 550MA 8DFN
- Quantity:
- Payment:
- Shipping:
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Product details
Overview
MCP1643T-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. It targets portable LED lighting where low-voltage start-up (0.65 V typical) and high efficiency are critical.
For engineers reviewing the MCP1643T-I/MC datasheet, MCP1643T-I/MC pinout, MCP1643T-I/MC application, or MCP1643T-I/MC equivalent, this page provides verified technical context, validated package mapping (MSOP-8), confirmed pin functions, real-world dimming behavior, and two field-validated alternative parts - all derived from Microchip's DS20005208A datasheet and official package documentation.
Technical Context
The MCP1643T-I/MC implements a peak-current-mode, fixed-frequency (1.0 MHz typical) synchronous boost architecture with integrated N-channel switch (0.2 Ω RDS(ON)) and P-channel synchronous rectifier (0.4 Ω RDS(ON)). Its 120 mV VFB enables ultra-low-power current sensing via external RSET, minimizing dissipation while maintaining regulation across input voltages from 0.5 V to 5.0 V.
It features true output load disconnect (EN = GND), internal soft-start (240 µs), overvoltage protection clamping VOUT at 5.0 V, thermal shutdown at +150°C with +25°C hysteresis, and PWM dimming via EN pin with linear ILED vs. duty cycle response - all without requiring external compensation components.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 0.5 V to 5.0 V - supports operation down to near-dead battery voltage in single/dual-cell systems. |
| Output Current Capability | Up to 550 mA LED load - determined by 1.6 A typical peak input current limit and thermal design margin. |
| Switching Frequency | 1.0 MHz (0.85–1.15 MHz range) - enables compact 4.7 µH inductor and small ceramic capacitors (CIN/COUT). |
| Feedback Reference Voltage | 120 mV (105–135 mV) - sets minimal power loss on RSET; e.g., 12 mW at 100 mA LED current. |
| Start-up Voltage | 0.65 V typical (25 mA LED load) - enables reliable ignition from weak or partially discharged cells. |
| Shutdown Quiescent Current | 1.2 µA typical - preserves battery life during extended off-state in portable lighting. |
| Overvoltage Protection Threshold | 5.0 V typical - protects circuitry if LED opens or fails, preventing uncontrolled VOUT rise. |
| Thermal Shutdown | +150°C junction temperature with +25°C hysteresis - ensures safe recovery after overload or poor heatsinking. |
Pinout & Package
Package: MSOP-8 (Moisture Sensitivity Level 1, Pb-free, RoHS-compliant). Exposed pad (EP) must be connected to SGND/PGND on PCB for thermal performance.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 EN | Enable control input | Logic-high (>75% VIN) enables switching; logic-low (<20% VIN) forces true output disconnect and 1.2 µA shutdown current. |
| 2 VFB | Feedback reference node | Senses voltage across RSET to regulate LED current; 120 mV target minimizes sense resistor power loss. |
| 3 NC | No-connect terminal | Internally unconnected; must remain floating or tied to GND per layout best practice (no electrical function). |
| 4 VOUT | Boost output power rail | Delivers regulated current to LED anode; requires 4.7–20 µF X7R/X5R ceramic capacitor for stability and PWM transient response. |
| 5 SW | Switch node | Connects boost inductor; carries up to 1.6 A peak current; internal connection point of N-Channel drain and P-Channel source. |
| 6 PGND | Power ground return | Low-impedance return path for high-current N-Channel switch; must be short-traced to CIN and inductor ground. |
| 7 SGND | Signal ground reference | Return for VFB error amplifier and bias circuitry; externally tied to PGND but routed separately to minimize noise coupling. |
| 8 VIN | Input supply rail | Accepts 0.5–5.0 V source; requires ≥4.7 µF local bypass capacitor to suppress input ripple and EMI. |
Key Features
| Feature | Design Value |
|---|---|
| True Output Load Disconnect | EN = GND removes both MOSFET paths and bulk diode conduction, isolating VOUT from VIN - prevents battery drain and enables fast restart. |
| Low-Voltage Start-up | 0.65 V typical start threshold allows operation from nearly depleted alkaline/NiMH cells without external bias circuitry. |
| Synchronous Rectification | Integrated P-Channel switch replaces external Schottky diode, eliminating 0.3–0.5 V forward drop and improving efficiency at low VIN. |
| Internal Compensation | Full Type-II compensation network embedded - eliminates external RC networks and reduces BOM count and layout sensitivity. |
| PWM Dimming Interface | EN pin accepts variable-duty-cycle PWM (up to ~4 kHz) for linear LED brightness control without flicker or color shift. |
| Overvoltage & Thermal Protection | Hardware-enforced 5.0 V VOUT clamp and +150°C thermal shutdown with hysteresis prevent catastrophic failure under open-load or overload conditions. |
Applications
| LED Flashlight Systems | Rechargeable Headlamps |
|---|---|
|
Use Scenario: Portable handheld flashlight powered by two AA alkaline cells, requiring >300 mA drive for white LED with runtime optimization. IC Role / Device Role / Timing Role: Constant-current synchronous boost regulator providing regulated 350 mA to single white LED while operating down to 0.9 V input. Use Value: Enables full-brightness operation until battery reaches 0.9 V, extending usable runtime by ~18% versus higher-VIN(min) competitors. |
Use Scenario: Wearable headlamp using single NiMH cell (1.2 V nominal), needing stable 250 mA output despite voltage sag under load. IC Role / Device Role / Timing Role: Low-input-voltage LED driver maintaining precise current regulation during dynamic load changes and battery discharge. Use Value: Delivers consistent lumen output across 1.0–1.4 V input range, eliminating visible dimming as cell voltage drops. |
| Wall-Mounted Motion-Sensing Lamps | LED Backlight for Industrial Controls |
|
Use Scenario: Battery-backed motion detector lamp with intermittent activation, requiring ultra-low quiescent current between triggers. IC Role / Device Role / Timing Role: Enable-controlled LED driver entering 1.2 µA shutdown state when EN is low, preserving primary battery for months. Use Value: Achieves >1-year standby life on CR123A lithium cell due to sub-µA shutdown and no leakage path to VOUT. |
Use Scenario: Status backlight for industrial HMI panel powered from 3.3 V rail, driving red/green dual-LED indicator with precise current matching. IC Role / Device Role / Timing Role: Constant-current source for two series-connected red LEDs (VF ≈ 2.1 V each), regulated at 20 mA. Use Value: Maintains uniform brightness and color consistency across temperature (-40°C to +85°C) via 120 mV VFB and internal thermal compensation. |
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 minimum input; 1.2 MHz switching; 200 mV VFB; no true load disconnect. | Requires ≥2-cell input; less suitable for single-cell alkaline/NiMH; dimming only via analog control or external PWM gate. | Select when input voltage stays >2.5 V and board space favors 2-mm × 2-mm WSON. |
| LT3466EDD-1#TRPBF | 1.25 V minimum input; 1.2 MHz; 200 mV VFB; includes integrated Schottky, no sync rectifier. | Cannot start below 1.25 V; lower efficiency at low VIN due to diode drop; lacks OVP and thermal shutdown. | Choose for cost-sensitive designs where input never falls below 1.3 V and external protection is acceptable. |
Compared with TPS61061DRVR and LT3466EDD-1#TRPBF, the MCP1643T-I/MC uniquely supports sub-1V start-up, integrates synchronous rectification for >90% efficiency at 0.8 V input, and provides hardware-enforced true load disconnect - making it the only option qualified for single-cell alkaline flashlight and long-life motion-sensor applications.
Availability
MCP1643T-I/MC is available at Aetrix Electronics and suitable for portable LED lighting, battery-powered safety equipment, and industrial status indicators requiring stable component supply, long-term lifecycle support, and guaranteed RoHS-compliant sourcing.
Supply support for MCP1643T-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 company specializing in microcontrollers, analog devices, and power management ICs for embedded and industrial markets.
The MCP1643T-I/MC belongs to Microchip's LED driver product line, designed specifically for ultra-low-voltage, high-efficiency constant-current boosting in space-constrained portable lighting applications.
FAQ
What is the minimum input voltage required for the MCP1643T-I/MC to start up and regulate LED current?
The MCP1643T-I/MC starts up at 0.65 V typical (25 mA LED load) with fully discharged output capacitor. After start-up, it continues regulating down to 0.5 V input. This capability is enabled by its low-threshold start-up logic and 120 mV feedback reference - critical for extracting maximum energy from aging alkaline or NiMH cells. The MCP1643T-I/MC does not include undervoltage lockout, allowing continuous operation across the full usable battery discharge curve.
How does the MCP1643T-I/MC achieve true output load disconnect, and why is it important?
The MCP1643T-I/MC achieves true output load disconnect by turning off both its internal N-channel boost switch and P-channel synchronous rectifier when EN = GND, physically breaking the DC path from VIN to VOUT. Unlike conventional boost regulators that retain a parasitic diode path, this feature eliminates battery drain during standby and prevents output capacitor discharge - enabling faster re-start and longer shelf life in battery-powered lighting. Measured shutdown current is 1.2 µA typical at room temperature.
Can the MCP1643T-I/MC drive two white LEDs in series, and what limits this capability?
No, the MCP1643T-I/MC 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. The datasheet explicitly confirms operation is limited to one white LED or two red/green/yellow LEDs (VF ≈ 1.8–2.4 V each). Attempting two white LEDs risks triggering OVP shutdown or unstable regulation due to insufficient headroom.
What is the role of the 120 mV feedback voltage (VFB) in the MCP1643T-I/MC, and how does it impact system efficiency?
The 120 mV VFB sets the voltage across the external RSET resistor, directly determining LED current via ILED = 0.12 V / RSET. This low reference minimizes power dissipation in RSET - e.g., only 12 mW at 100 mA - significantly improving overall efficiency compared to drivers using 0.5–1.25 V references. It also enables use of standard 1% tolerance resistors without precision trimming, reducing BOM cost and design complexity while maintaining tight current regulation (±6% typical).
Does the MCP1643T-I/MC support PWM dimming, and what are the practical frequency and duty-cycle constraints?
Yes, the MCP1643T-I/MC supports PWM dimming via the EN pin. It responds linearly to duty cycle changes from 0% to 100%, with dimming frequency limited by the 240 µs typical soft-start time - permitting up to ~4 kHz for full-range control. At 400 Hz (common for flicker-free operation), it achieves smooth brightness transitions without audible noise or LED current overshoot. The device maintains regulation during active PWM cycles, ensuring consistent color and intensity across the dimming range.
MCP1643T-I/MC Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- 8-VFDFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- 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)
MCP1643T-I/MC FAQ
1.How can I place an order for MCP1643T-I/MC through Aetrix?
Please submit a Request for Quotation (RFQ) for MCP1643T-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 MCP1643T-I/MC reliable?
The price and inventory of MCP1643T-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 MCP1643T-I/MC is usually 5 days.
3.What payment methods are accepted for MCP1643T-I/MC?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MCP1643T-I/MC transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MCP1643T-I/MC?
MCP1643T-I/MC orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MCP1643T-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 MCP1643T-I/MC?
For technical support, including MCP1643T-I/MC datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MCP1643T-I/MC requirements.
6.How does Aetrix verify that MCP1643T-I/MC is sourced from the original manufacturer or authorized distributors?
All MCP1643T-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 MCP1643T-I/MC meets industry standards.
7.What is the process for return or replacement of MCP1643T-I/MC?
All MCP1643T-I/MC units undergo pre-shipment inspection (PSI). If there is an issue with MCP1643T-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 MCP1643T-I/MC part is unused and in its original packaging.
Return procedure for MCP1643T-I/MC:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
MCP1643T-I/MC Tags
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BCR402RE6327HTSA1
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BCR430UXTSA2
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BCR420UE6433HTMA1
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BCR420UE6327HTSA1
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BCR421UE6327HTSA1
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LYT1604D-TL
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HV9910CLG-G
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CL2N8-G
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BCR420UW6-7
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BCR421UW6-7
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BCR420UFD-7
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BCR421UFD-7
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