MCP1643-I/MC - 550mA Sync Boost LED Driver, 1MHz | Microchip
N.º da peça: MCP1643-I/MC ✓ Ativo| Qtd. | Preço unitário | Total |
|---|---|---|
| 1 | $1.42 | $1,42 |
| 10 | $1.27 | $12,70 |
| 100 | $1.09 | $109,00 |
| 500 | $0.95 | $475,00 |
| 1.000 | $0.82 | $820,00 |
| 3.000 | $0.68 | $2.040,00 |
MCP1643-I/MC Visão geral
A boost (step-up) converter is a switched-mode DC-DC topology that produces an output voltage higher than its input by storing energy in an inductor during the switch-on period and releasing it into the output capacitor through a rectifier during switch-off. Synchronous rectification replaces the external Schottky diode with an internal low-side MOSFET, improving efficiency at light loads and reducing solution size - critical for portable lighting applications where every microwatt counts. The MCP1643 family adds constant-current regulation on top of the boost topology, so LED brightness remains stable as the battery droops or as the LED forward voltage changes with temperature.
Key features include a 550 mA switch current limit, an integrated low-side synchronous switch, 0.65 V input startup voltage, fixed 1 MHz PWM operation, built-in over-temperature protection, and PWM duty-cycle brightness control on the EN/PWM pin. The 8-pin DFN package (2x3 mm) keeps the PCB footprint extremely small, allowing this regulator to fit inside an LED flashlight head or a wearable indicator.
The internal architecture combines a current-mode PWM control core, an N-channel high-side switch, an N-channel synchronous low-side switch, an internal bandgap reference, and a feedback loop that regulates peak switch current - delivering constant LED brightness even as battery voltage drops below the LED forward voltage. The 1 MHz switching frequency allows the use of a tiny 4.7 uH inductor and small ceramic capacitors.
Typical applications include LED flashlight drivers, portable backlight drivers for LCD displays, wearable device indicators, emergency lighting, and battery-powered signage. The wide 0.65 V to 5 V input range makes the device directly compatible with single-cell alkaline, single-cell NiMH, two-cell alkaline, and even USB/Li-ion sources through a simple resistive divider.
When designing with the MCP1643-I/MC, select a 4.7 uH inductor with low DCR and a saturation current above 1 A, place input/output ceramics close to the IC, and use the EN/PWM pin for brightness dimming with a 100 Hz to 1 kHz PWM signal. The exposed pad must be soldered to a grounded copper pour for thermal dissipation.
This page synthesizes distributor pricing, drop-in alternatives, and practical design notes not found in the manufacturer datasheet.
Alternativas drop-in para MCP1643-I/MC — mesmo encapsulamento, compatível pino a pino. Peças de encapsulamento diferente que exigem retrabalho na PCB são excluídas.
Ferramenta de comparação rápida — selecione peças alternativas para comparação lado a lado:
MCP1643-I/MSVAO
✅ Drop-In📋 Alternativa de referência (fora do catálogo)
MCP1643T-I/MC
✅ Drop-In📋 Alternativa de referência (fora do catálogo)
MCP1643T-I/MS
✅ Drop-In📋 Alternativa de referência (fora do catálogo)
MCP1643T-I/MF
✅ Drop-In📋 Alternativa de referência (fora do catálogo)
MCP1643-I/MF
✅ Drop-In📋 Alternativa de referência (fora do catálogo)
MCP1643-I/MC Classificações máximas e características elétricas
| Topologia | Synchronous Step-Up (Boost) |
| Função | LED Constant-Current Driver |
| Faixa de tensão de entrada | 0.65 V to 5 V |
| Tensão de saída - máx. | 5 V |
| Switch Current Limit | 550 mA |
| Frequência de comutação | 1 MHz (fixed) |
| Número de saídas | 1 |
| Dimming Method | PWM (EN/PWM pin) |
| Retificador síncrono | Yes (integrated low-side MOSFET) |
| Faixa de temperatura de operação | -40C to +125C |
| Encapsulamento | 8-pin DFN (2x3 mm) |
| Tipo de montagem | Surface Mount |
| Nível MSL | 1 |
| Thermal Protection | Yes (over-temperature shutdown) |
| Status RoHS | Compliant |
| Low-Battery Start | 0.65 V cold-start capable |
Configuração de pinos do MCP1643-I/MC
| Pino 1 | SW — Switch node - connect to inductor |
| Pino 2 | SW — Switch node - connect to inductor |
| Pino 3 | EN/PWM — Enable and PWM dimming input |
| Pino 4 | GND — Analog ground |
| Pino 5 | FB — Feedback voltage input (Vref = 0.6 V) |
| Pino 6 | VIN — Input supply voltage (0.65 V to 5 V) |
| Pino 7 | VOUT — Regulated output voltage (up to 5 V) |
| Pino 8 | PGND — Power ground and exposed thermal pad |
Aplicações típicas
MCP1643-I/MC é adequado para 6 aplicaçãos: LED Flashlight Driver (Single-Cell Alkaline), Portable LCD Backlight Driver, Wearable Indicator / Status LED, Emergency Lighting / Signage, Two-Cell NiMH / NiCd Battery Lighting, USB-Powered LED Task Light.
LED Flashlight Driver (Single-Cell Alkaline)
The MCP1643-I/MC is purpose-built for single-cell alkaline LED flashlight drivers, leveraging its 0.65 V cold-start capability - the lowest startup voltage of any synchronous boost LED regulator in its class per the Microchip datasheet. A depleted alkaline cell at ~0.9 V still powers a 1 W white LED (~3.0 V Vf) because the boost topology generates the higher LED voltage while the synchronous rectifier keeps efficiency above 85%. Placed between the battery and the LED with a 4.7 uH inductor and 1 uF ceramic caps, the device delivers up to 550 mA switch current for >200 lumen output. Unlike non-synchronous boost LEDs that lose ~250 mV in a Schottky diode, the integrated low-side MOSFET saves enough power to extend runtime by 15-20% on the same battery.
Recomendado
Portable LCD Backlight Driver
The MCP1643-I/MC drives portable LCD backlight LEDs from a single-cell Li-ion or two-cell alkaline source, providing constant current regulation that prevents brightness variation as the battery droops. With a fixed 1 MHz PWM frequency per the Microchip datasheet, the device allows a 4.7 uH inductor and tiny ceramic capacitors - critical for the sub-30 mm^2 backlight area in wearable displays. The EN/PWM pin accepts a 100 Hz to 1 kHz dimming signal directly from the host MCU, enabling software brightness control without additional analog circuitry. Compared to charge-pump backlight drivers the synchronous boost topology delivers higher efficiency at the larger Vf deltas typical of 3-4 series backlight LEDs.
Recomendado
Wearable Indicator / Status LED
The MCP1643-I/MC's tiny 8-pin DFN (2x3 mm) footprint makes it ideal for wearable indicator LEDs in fitness bands, smart watches and Bluetooth beacons where board space is measured in square millimeters. Operating from a 3 V coin cell or small LiPo, the synchronous boost topology delivers stable LED brightness for status indication or RGB signaling without draining the battery. The constant-current regulation prevents visible brightness drift as the battery discharges from 4.2 V to 3.0 V over the device's lifetime. The exposed pad provides sufficient thermal dissipation for the 200-300 mW typical dissipation in indicator duty cycles.
Recomendado
Emergency Lighting / Signage
The MCP1643-I/MC is well suited to emergency exit signs and battery-backed safety lighting, providing reliable LED illumination from a primary battery source for the multi-year shelf life of safety equipment. Its 0.65 V startup voltage ensures the LED lights even when the battery has partially self-discharged during storage, eliminating the common failure mode of competitors that require 0.9 V or higher to start. The built-in over-temperature protection prevents thermal runaway if the LED is mis-wired or shorted, a critical reliability feature for safety-certified products. Efficiency above 85% extends runtime during power outages compared to non-synchronous alternatives.
Recomendado
Two-Cell NiMH / NiCd Battery Lighting
The MCP1643-I/MC's wide 0.65 V to 5 V input range covers two-cell NiMH or NiCd battery packs delivering 2.0 V to 3.0 V nominal, making it ideal for cordless task lighting, garden lights and rechargeable flashlights. The synchronous boost maintains constant LED brightness throughout the discharge curve, unlike resistive current-limiters that let the LED fade as the battery drains. The 1 MHz switching frequency stays above the AM radio band, avoiding audible interference in radio-equipped products. Microchip's datasheet specifies a 4.7 uH inductor as the recommended value for two-cell NiMH operation.
Recomendado
USB-Powered LED Task Light
The MCP1643-I/MC operates from a 5 V USB rail directly, making it suitable for USB-powered task lights, USB reading lamps and USB-powered grow-light strips. The constant-current regulation protects the connected LEDs from USB voltage variations and inrush events. The PWM dimming capability on the EN/PWM pin allows USB hosts or simple button-interface circuits to control brightness in 256 or 1000 steps. The 8-DFN package's small footprint and exposed thermal pad enable fanless designs that meet USB 2.0/3.0 enclosure thermal limits.
Recomendado
Resumo dos produtos recomendados
Dados de referência de engenharia para MCP1643-I/MC — comparação, orientação de projeto e informações de conformidade.
Guia de seleção
Comparação com alternativas
| Parâmetro | Este produto | MCP1643-I/MSVAO | MCP1643T-I/MC | MCP1643T-I/MS | MCP1643T-I/MF | MCP1643-I/MF |
|---|---|---|---|---|---|---|
| Package | 8-DFN (2x3 mm) | 8-MSOP (different package) | 8-DFN (2x3 mm) - same | 8-MSOP (different package) | 8-DFN (2x3 mm) - same | 8-DFN (2x3 mm) - same |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Input Voltage Range | 0.65 V to 5 V | 0.65 V to 5 V | 0.65 V to 5 V | 0.65 V to 5 V | 0.65 V to 5 V | 0.65 V to 5 V |
| Switch Current Limit | 550 mA | 550 mA | 550 mA | 550 mA | 550 mA | 550 mA |
| Switching Frequency | 1 MHz | 1 MHz | 1 MHz | 1 MHz | 1 MHz | 1 MHz |
| Automotive Grade (AEC-Q100) | No | Yes | No | No | No | No |
| Output Voltage (Max) | 5 V | 5 V | 5 V | 5 V | 5 V | 5 V |
| Topology | Synchronous Boost | Synchronous Boost | Synchronous Boost | Synchronous Boost | Synchronous Boost | Synchronous Boost |
Principais diferenciais
- Lowest startup voltage of any synchronous boost LED driver in its class (vs TI LM3561)
- Synchronous rectification with integrated low-side switch (vs Non-synchronous boost LED drivers (e.g. LM3561))
- Automotive grade variant available in same die (vs MCP1643-I/MC (industrial) vs MCP1643-I/MSVAO (AEC-Q100))
Notas de projeto
Select a 4.7 uH inductor with DCR below 100 mohm and saturation current rated above 1 A (1.5x the 550 mA switch limit). The MCP1643 datasheet recommends a shielded power inductor such as the Coilcraft XPL2010 or equivalent. Using a smaller inductor (2.2 uH) increases ripple current and may trigger the current limit prematurely; using a larger inductor (10 uH) reduces ripple but increases solution size and may slow the transient response below audible requirements.
Estimated: at VIN=1.5 V, VOUT=3.3 V, and IOUT=200 mA the device dissipates roughly (3.3-1.5)*0.2 + switching losses = ~0.4 W. The 8-DFN package's exposed thermal pad must be soldered to a grounded copper pour of at least 100 mm^2 on the top layer to keep the junction temperature below 125C. Without the thermal pad properly soldered the device may enter thermal shutdown at higher load currents.
Place the input capacitor (1 uF X7R ceramic) within 2 mm of the VIN pin and the output capacitor (1 uF X7R ceramic) within 2 mm of the VOUT pin to minimize switching noise coupling. Keep the switch-node (SW) trace short and away from sensitive analog traces. Route the feedback (FB) trace away from the SW node and use a ground guard ring around the feedback resistor divider to prevent noise injection that could cause LED flicker.
Do not omit the input capacitor - the MCP1643's synchronous boost topology requires a local input reservoir to handle the discontinuous input current. Without CIN, VIN droop during switch transitions can cause the device to reset or oscillate. Similarly, do not use the EN/PWM pin as an analog dimming input - the pin is a digital input, and analog voltages between thresholds cause unpredictable LED brightness. Use PWM dimming only.
Informações de conformidade
RoHS and REACH compliant per Microchip product page. Not AEC-Q100 qualified - choose MCP1643-I/MSVAO suffix for automotive applications. Halogen-free per Microchip material declaration.
