LM3405XMKX/NOPB - 1A 1.6MHz Constant-Current Buck LED Driver | TI
N.º de pieza: LM3405XMKX/NOPB ✓ Activo| Cant. | Precio unitario | Total |
|---|---|---|
| 1 | $1.62 | $1,62 |
| 10 | $1.45 | $14,50 |
| 100 | $1.18 | $118,00 |
| 500 | $0.98 | $490,00 |
| 1.000 | $0.84 | $840,00 |
LM3405XMKX/NOPB Descripción general
An LED driver is a semiconductor device that regulates current through one or more LEDs to ensure consistent luminance, color, and reliability. Constant-current buck (step-down) LED drivers are a sub-category of switching power converters that combine a power MOSFET, inductor current-sense amplifier, and feedback loop. They sit within the broader taxonomy of LED drivers > power management ICs > semiconductors. Their main role is to convert a higher DC bus voltage (e.g., 5V, 12V, or a Li-Ion cell) into a precisely regulated LED string current, eliminating the efficiency loss and thermal stress of a series resistor.
Key features include a 3V to 15V input voltage range, internal 1-A N-channel MOSFET, 0.205-V feedback reference voltage for low-loss current sensing, 1.6-MHz fixed switching frequency that enables small ceramic input/output capacitors and chip inductors, and a TTL-compatible enable/PWM dimming pin. The device includes internal compensation, cycle-by-cycle current limit, and thermal shutdown for robust operation in space-constrained lighting modules.
The architecture is a peak-current-mode controlled buck converter with internal compensation. The 1.6-MHz switching frequency is well above the AM radio band, simplifying EMI compliance for consumer products. The low 0.205-V reference across the external sense resistor keeps conduction loss below 1% of the LED current, which is critical in 1-A high-power LED applications where even 0.3V drop wastes 300 mW.
Typical applications include camera phone flash/torch LED drivers, portable LED flashlights, display backlighting, signage and architectural lighting, and any 1-A class high-brightness LED string on a 5V or single-cell Li-Ion bus. The small TSOT-23-6 footprint also suits wearable and IoT lighting nodes.
When designing with this part, choose the sense resistor with low-ESR tolerance (1% or better) to keep current setpoint accuracy within ±5%, and size the buck inductor to maintain continuous conduction mode at the minimum dimming duty. Keep the high-frequency loop (input cap, SW node, low-side ground) tight on the PCB to minimize EMI.
This page synthesizes distributor pricing, drop-in alternative options, and PCB-level design considerations that are not consolidated in the manufacturer datasheet, giving procurement and design engineers a single reference for evaluation.
Alternativas directas para LM3405XMKX/NOPB — mismo encapsulado, compatible pin a pin. Se excluyen las piezas de otro encapsulado que requieren retrabajo de la PCB.
Variantes de esta serie
Modelos de la misma serie compatibles directamente con LM3405XMKX/NOPB (mismo factor de forma y huella) — difiere en Input Voltage Range, MSL Level, Switching Frequency, Topology.
Herramienta de comparación rápida — seleccione piezas alternativas para compararlas lado a lado:
LM3405XMK/NOPB
✅ Sustitución directa📋 Alternativa de referencia (no en el catálogo)
LM3405AXMK/NOPB
✅ Sustitución directa📋 Alternativa de referencia (no en el catálogo)
LM3405AXMKE/NOPB
✅ Sustitución directa✓ En stock
$0.66 / unidad
Ver hoja de datos →LM3405XMKX/NOPB Valores máximos y características eléctricas
| Topología | Step-Down (Buck), Constant Current |
| Número de salidas | 1 |
| Rango de tensión de entrada | 3 V to 15 V |
| Output Current (LED) | 1 A (max) |
| Frecuencia de conmutación | 1.6 MHz (typ, internal) |
| Feedback Reference Voltage | 0.205 V |
| Internal MOSFET | Yes (N-channel, 1 A) |
| Dimming Control | PWM (EN/DIM pin, TTL) |
| Eficiencia | Up to 95% (typical, application dependent) |
| Rango de temperatura de funcionamiento | -40 C to +125 C |
| Encapsulado | TSOT-23-6 (DDC), 6 pins |
| Tipo de montaje | Surface Mount |
| Nivel MSL | 1 |
| Apagado térmico | Yes (internal) |
| Limitación de corriente | Cycle-by-cycle (internal) |
| Estado RoHS | Compliant |
Configuración de pines de LM3405XMKX/NOPB
| Pin 1 | EN/DIM — Enable / PWM dimming input (TTL-compatible, internal pull-up) |
| Pin 2 | GND — Ground return |
| Pin 3 | FB — Feedback (current sense, 0.205V reference) |
| Pin 4 | NC — Not connected (per datasheet) |
| Pin 5 | VIN — Input supply (3V to 15V) |
| Pin 6 | SW — Switch node (internal N-MOSFET drain) |
Aplicaciones típicas
LM3405XMKX/NOPB es adecuado para 6 aplicacións: Camera Phone Flash/Torch LED Driver, Portable LED Flashlight, LCD Display Backlighting, Automotive Interior Lighting, IoT Smart Lighting Node, Signage and Architectural LED Strip.
Camera Phone Flash/Torch LED Driver
The LM3405XMKX/NOPB is a strong match for camera phone flash and torch LED drivers because it delivers a precisely regulated 1A peak current from a single-cell Li-Ion (3V-4.2V) input, with 1.6-MHz switching that places EMI above the camera sensor's sensitive band. The 0.205V reference across the external sense resistor keeps conduction loss below 1%, critical for flash events where 0.5-1.5A peaks must be sustained for 100-500 ms. The EN/DIM pin accepts a PWM signal from the camera ISP for fine brightness control in torch mode and a hard enable for flash mode, simplifying host software.
Recomendado
Portable LED Flashlight
The LM3405XMKX/NOPB suits portable LED flashlight designs because its 3V-15V input range covers both single 18650 Li-Ion cells and 2-3 cell battery packs without a boost stage. The 1A constant-current regulation maintains constant lumen output as battery voltage sags from 4.2V down to 3.2V, eliminating the dimming effect common in resistor-biased flashlights. The TSOT-23-6 footprint fits inside tubular flashlight heads, and the EN/DIM pin can be tied to a tactile pushbutton with optional PWM for adjustable brightness levels.
Recomendado
LCD Display Backlighting
The LM3405XMKX/NOPB is well suited to LCD display backlighting where uniform luminance across a parallel LED string is required. Its 0.205V reference and external sense resistor set the LED current to within ±5% across all LEDs in the string, eliminating brightness mismatch. The 1.6-MHz switching frequency keeps the converter above the AM broadcast band, simplifying EMI compliance for monitors and TVs that must meet EN 55015/CISPR 15 limits. PWM dimming on the EN/DIM pin maps directly to a backlight brightness control signal from the display controller.
Recomendado
Automotive Interior Lighting
The LM3405XMKX/NOPB can drive automotive interior LED strings such as dome lights, reading lamps, and accent lighting from a 12V automotive bus. Its 15V maximum input tolerates load-dump transients up to the typical 16V clamp level, and the internal thermal shutdown protects against LED failure modes. The 1.6-MHz switching enables a small inductor that fits under the headliner or inside a door-trim LED module. Note that for AEC-Q100 qualified applications, the TI LM3405-Q1 variants or alternative automotive-grade LED drivers should be used instead of the standard part.
Recomendado
IoT Smart Lighting Node
The LM3405XMKX/NOPB fits small IoT smart lighting nodes such as connected downlights and outdoor garden lights because its TSOT-23-6 package and 1.6-MHz frequency allow a complete LED driver circuit under 25 mm². The 3V-15V input range supports both battery-powered and mains-stepped-down supplies, and the low 6-mA typical quiescent current (when disabled) preserves battery life in standby. The EN/DIM pin can be driven directly by a GPIO from a wireless MCU for cloud-controlled dimming. The high switching frequency keeps EMI low for the integrated BLE/Wi-Fi radio band.
Recomendado
Signage and Architectural LED Strip
The LM3405XMKX/NOPB is a cost-effective driver for signage and architectural LED strips, especially in 12V or 24V bus systems where multiple 1A LED zones need to be driven individually. The high 1.6-MHz switching frequency supports small ceramic-only capacitors, which is preferable in outdoor fixtures where electrolytic lifetime is a concern. The PWM dimming input enables per-zone brightness control from a central controller, and the 1A constant current maintains uniform brightness across long LED runs where forward voltage varies with temperature.
Recomendado
Resumen de productos recomendados
Datos de referencia de ingeniería para LM3405XMKX/NOPB — comparación, orientación de diseño e información de cumplimiento.
Guía de selección
Comparación con alternativas
| Parámetro | Este producto | LM3405XMK/NOPB | LM3405AXMK/NOPB | LM3405AXMKE/NOPB |
|---|---|---|---|---|
| Package | TSOT-23-6 (DDC) | TSOT-23-6 (DDC) - same | TSOT-23-6 (DDC) - same | TSOT-23-6 (DDC) - same |
| Brand | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments |
| Output Current (max) | 1 A | 1 A | 1 A | 1 A |
| Input Voltage Range | 3 V to 15 V | 3 V to 15 V | 3 V to 15 V | 3 V to 15 V |
| Switching Frequency | 1.6 MHz (internal) | 1.6 MHz | 1.6 MHz | 1.6 MHz |
| Feedback Reference Voltage | 0.205 V | 0.205 V | 0.205 V | 0.205 V |
| PWM Dimming | Yes (EN/DIM pin) | Yes | Yes | Yes |
| Reel Quantity | 3000 (XMKX suffix) | 1000 (XMK suffix) | 1000 (AXMK suffix) | 250 (AXMKE suffix) |
| Silicon Revision | Original | Original | A-revision | A-revision |
Diferenciadores clave
- 1.6-MHz switching enables sub-25 mm² total solution footprint (frente a Lower-frequency 1-A LED drivers (e.g. 500-kHz class))
- Low 0.205V feedback reference minimizes sense-resistor power loss (frente a Drivers using 0.5V or 1.0V reference voltage)
- TSOT-23-6 package with 1-A capability in 6 pins (frente a Larger SOT-23-6 or MSOP-8 LED drivers at 1A)
Notas de diseño
The LM3405XMKX/NOPB uses a 0.205V feedback reference rather than the more common 0.1V or 0.5V. Choosing a sense resistor with 1% tolerance and low TCR (under 100 ppm/C) is critical to maintain current setpoint accuracy across temperature. A 0.1 ohm 2512-size resistor in parallel with a 0.1 ohm 0805 allows fine trimming at calibration. Do not exceed 15V on VIN; the internal MOSFET is not rated for automotive load-dump transients above this value.
Keep the high-frequency switching loop (VIN capacitor positive terminal to SW pin to GND return) as tight as possible, ideally under 5 mm of total loop length, to minimize radiated EMI. Place the input capacitor within 2 mm of the VIN pin and use a 1-uF X5R/X7R 25V ceramic. The exposed thermal pad on the TSOT-23-6 underside should be soldered to a copper pour of at least 10 mm² to keep junction temperature rise below 50 C at 1-A continuous load.
Estimated: at VIN=12V, VOUT=5V (LED forward voltage), and 1-A continuous load, the LM3405XMKX/NOPB dissipates roughly (12V-5V) * 1A * (1-efficiency) of additional heat. With typical 90% efficiency, internal dissipation is approximately 0.78W. The TSOT-23-6 (DDC) package has a theta_JA of around 50 C/W on a 1-oz 4-layer JEDEC test board, producing a 39 C junction temperature rise. Continuous 1-A operation is feasible with proper PCB copper, but for ambient temperatures above 70 C a 0.5-A derating is recommended.
Información de cumplimiento
RoHS and REACH compliant per TI product page. NOPB suffix indicates Pb-free (lead-free) and RoHS compliance. Standard part is not AEC-Q100 qualified; for automotive applications, choose a -Q1 variant or qualified alternative.
