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Texas Instruments LM3405XMK/NOPB
- Part No.:
- LM3405XMK/NOPB
- Manufacturer:
- Texas Instruments
- Category:
- LED Drivers
- Package:
- SOT-23-6 Thin, TSOT-23-6
- Datasheet:
-
LM3405XMK/NOPB.pdf
- Description:
- IC LED DRV RGLTR PWM 1A TSOT23-6
- Quantity:
- Payment:
- Shipping:
Inventory:5,286
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Product details
Overview
LM3405XMK/NOPB from Texas Instruments is a 1.6-MHz, 1-A constant-current buck LED driver in SOT-6 package, featuring 0.205-V feedback reference, 300-mΩ internal NMOS switch, and EN/DIM pin for PWM dimming. It drives up to 5 high-brightness LEDs in series at 1 A from 3–15 V input, used in portable LED flashlights and industrial lighting systems.
For engineers reviewing the LM3405XMK/NOPB datasheet, LM3405XMK/NOPB pinout, LM3405XMK/NOPB application, or LM3405XMK/NOPB equivalent, key selection considerations include its fixed 1.6-MHz switching frequency, thermal shutdown protection, cycle-by-cycle current limit, UVLO with 440-mV hysteresis, and compatibility with ceramic output capacitors for compact layout.
Technical Context
The LM3405XMK/NOPB uses current-mode control with internal compensation and a fixed 1.6-MHz oscillator, enabling stable regulation without external loop compensation. Its 0.205-V FB reference minimizes power loss in the current-sense resistor, while the BOOST/SW bootstrap architecture sustains gate drive voltage between 2.5 V and 5.5 V for optimal RDS(ON) performance.
It implements cycle-by-cycle current limiting (typ. 2 A), overcurrent protection triggered at 328 mV on FB (60% above VFB), and thermal shutdown at 165°C. The EN/DIM pin supports both logic-level enable and PWM dimming (100 Hz–5 kHz), with 100-µs startup delay from enable assertion to full LED current regulation.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VIN Range | 3 V to 15 V - supports single-cell Li-ion to multi-cell battery and 12-V rail inputs without pre-regulation. |
| Switching Frequency | 1.6 MHz (typ.) - enables use of small 1–2.2-µH SMT inductors and low-ESR ceramic capacitors. |
| Feedback Voltage (VFB) | 0.205 V (typ.) - sets LED current via external resistor (IF = 0.205 V / R1); minimizes I²R loss in sense network. |
| RDS(ON) | 300 mΩ (typ.) - limits conduction loss at 1-A load; reduces thermal stress in SOT-6 package. |
| Shutdown Current | 0.3 µA (typ. at VIN = 5 V) - enables ultra-low-power standby in battery-powered LED systems. |
| UVLO Threshold | 2.95 V (rising), 2.3 V (falling) - prevents erratic operation during brown-out; 440-mV hysteresis avoids chatter. |
| Current Limit | 2 A (typ.) - provides cycle-by-cycle protection against shorted LED strings or inductor saturation. |
Pinout & Package
SOT-6 (DDC) package, 2.90 mm × 1.60 mm body size, thermally enhanced bottom-pad design with 182.9°C/W junction-to-ambient thermal resistance.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| BOOST | Bootstrap supply output | Drives NMOS gate; requires external capacitor to SW; must maintain 2.5–5.5 V above SW for reliable switching. |
| GND | Signal and power ground | Reference for FB, EN/DIM, and internal circuits; PCB copper pour under package improves thermal performance. |
| FB | Current-sense feedback input | Monitors cathode-side voltage drop across R1; regulates LED current by holding at 0.205 V. |
| EN/DIM | Enable and PWM dimming control | Logic-high (>1.8 V) enables operation; PWM signal (100 Hz–5 kHz) modulates LED brightness with ~100-µs response. |
| VIN | Main input supply | Accepts 3–15 V; requires local 1-µF ceramic bypass capacitor to GND for stability and noise suppression. |
| SW | Power switch node | Connects to inductor, catch diode anode, and BOOST capacitor; carries high di/dt; requires tight layout to minimize EMI. |
Key Features
| Feature | Design Value |
|---|---|
| Internally compensated current-mode control | Eliminates need for external compensation components; ensures stable regulation across input/output/temperature variations. |
| 1.6-MHz fixed-frequency operation | Enables compact BOM with standard 1.0–2.2-µH shielded ferrite inductors and X5R/X7R ceramic output capacitors. |
| 0.205-V precision feedback reference | Reduces power dissipation in current-sense resistor by >5× vs. typical 1.25-V references, critical for high-current LED apps. |
| Thermal shutdown + cycle-by-cycle current limit | Provides dual-layer protection: immediate per-cycle cutoff for transient overloads and sustained thermal fault shutdown at 165°C. |
| EN/DIM pin with 100-µs startup latency | Supports both hard enable and analog-equivalent PWM dimming; predictable timing enables synchronization with system controllers. |
Applications
| Portable LED Flashlights | Automotive Interior Lighting |
|---|---|
|
Use Scenario: High-intensity handheld illumination powered by single Li-ion cell (3.0–4.2 V). IC Role / Device Role / Timing Role: Constant-current buck regulator maintaining 1-A LED string current despite battery voltage sag. Use Value: Delivers consistent lumen output over full battery discharge curve using only 6-pin SOT-6 footprint and no external compensation. |
Use Scenario: Map light or dome light module requiring adjustable brightness and EMI-compliant operation. IC Role / Device Role / Timing Role: PWM-dimmable LED driver synchronized to vehicle microcontroller via EN/DIM pin. Use Value: Achieves flicker-free dimming from 100 Hz to 5 kHz with <100-µs enable latency and built-in overcurrent/thermal protection. |
| Industrial Panel Indicators | USB-Powered LED Task Lights |
|
Use Scenario: Status indicators on factory HMIs requiring long-life, stable brightness under 12-V DC supply. IC Role / Device Role / Timing Role: Fixed-frequency buck controller driving 3-series white LEDs with minimal component count. Use Value: Enables compact PCB layout with 1.6-MHz switching, eliminating need for large electrolytic capacitors or magnetic shielding. |
Use Scenario: Low-cost desk lamp powered directly from USB 5-V source with brightness control. IC Role / Device Role / Timing Role: Efficient 5-V-to-LED-string converter with shutdown current <0.5 µA for USB suspend compliance. Use Value: Meets USB power budget constraints while delivering full 1-A LED current and supporting software-controlled dimming. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar constant-current LED driver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM3404MH/NOPB | Higher 1.6-A current limit, 500-kHz switching, SO-8 package - larger footprint, lower frequency allows bigger inductors. | Better suited for higher-power LED arrays (>1 A) where thermal headroom and lower EMI priority over size. | Select when >1-A peak current capability or SO-8 thermal mass is required; not pin-compatible with LM3405XMK/NOPB. |
| TPS61061DRVR | Boost topology, 40-V output, 0.5-A max, 1.2-MHz, 6-pin WSON - supports >5-LED strings but cannot step down. | Required when input voltage is below LED forward voltage (e.g., 3.3-V rail driving 3×3.7-V LEDs). | Choose for boost-based designs; incompatible for buck-only topologies; different pinout and control scheme. |
Compared with LM3404MH/NOPB and TPS61061DRVR, the LM3405XMK/NOPB uniquely balances 1-A buck capability, 1.6-MHz frequency, and SOT-6 size-making it optimal for space-constrained, medium-power LED applications where input exceeds LED string VF.
Availability
LM3405XMK/NOPB is available at Aetrix Electronics and suitable for portable LED flashlights, automotive interior lighting, and industrial panel indicators requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.
Supply support for LM3405XMK/NOPB 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
Texas Instruments is a global semiconductor company designing analog ICs, embedded processors, and power management solutions for industrial, automotive, and consumer applications.
The LM3405XMK/NOPB belongs to TI's LED driver product line, engineered specifically for compact, high-efficiency constant-current buck conversion in portable and space-sensitive lighting systems.
FAQ
What is the recommended inductor value for LM3405XMK/NOPB operating at 1 A LED current?
The LM3405XMK/NOPB datasheet recommends 1.0–2.2 µH for 1-A operation at 1.6 MHz. A 1.5-µH shielded ferrite inductor with ≥2-A saturation current and low DCR ensures stable ripple ratio (~0.35) and avoids saturation during startup transients. TI's reference design TIDA-00225 validates 1.5 µH as optimal for efficiency and thermal performance in SOT-6 layout.
Can LM3405XMK/NOPB drive more than 5 LEDs in series?
No - the LM3405XMK/NOPB is rated to drive up to 5 high-brightness LEDs in series at 1 A, assuming ~3.7 V per LED (18.5 V total VF). With maximum input of 15 V, the device cannot sustain regulation beyond ~3 LEDs at 1 A. For longer strings, a boost or buck-boost topology like TPS61061DRVR is required.
What is the minimum LED current supported by LM3405XMK/NOPB without instability?
The LM3405XMK/NOPB requires ≥200 mA average LED current for stable regulation in constant-current mode. Below this, current-loop stability degrades. For dimmed operation below 200 mA, PWM dimming via the EN/DIM pin is recommended - the IC maintains full 1-A capability during active on-time, ensuring precise low-duty-cycle control.
Does LM3405XMK/NOPB require external compensation components?
No - the LM3405XMK/NOPB features internally compensated current-mode control. No external compensation network (e.g., Type II/III compensator) is needed. This simplifies design, reduces BOM count, and guarantees stability across all recommended operating conditions (3–15 V input, –40°C to 125°C).
How does the BOOST pin function in LM3405XMK/NOPB, and what capacitor value is recommended?
The BOOST pin supplies gate drive voltage to the internal NMOS switch via a bootstrap capacitor connected to SW. A 0.1-µF X7R ceramic capacitor (rated ≥10 V) is recommended between BOOST and SW. This ensures sufficient charge storage to maintain 2.5–5.5 V gate drive during each switching cycle, minimizing RDS(ON) and conduction loss.
LM3405XMK/NOPB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- SOT-23-6 Thin, TSOT-23-6
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Type:
- DC DC Regulator
- Topology:
- Step-Down (Buck)
- Internal Switch(s):
- Yes
- Number of Outputs:
- 1
- Voltage - Supply (Min):
- 3V
- Voltage - Supply (Max):
- 15V
- Voltage - Output:
- 13.5V
- Current - Output / Channel:
- 1A
- Frequency:
- 1.6MHz
- Dimming:
- PWM
- Applications:
- Lighting
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- TSOT-23-6
LM3405XMK/NOPB FAQ
1.How can I place an order for LM3405XMK/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM3405XMK/NOPB 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 LM3405XMK/NOPB reliable?
The price and inventory of LM3405XMK/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM3405XMK/NOPB is usually 5 days.
3.What payment methods are accepted for LM3405XMK/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM3405XMK/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM3405XMK/NOPB?
LM3405XMK/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM3405XMK/NOPB 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 LM3405XMK/NOPB?
For technical support, including LM3405XMK/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM3405XMK/NOPB requirements.
6.How does Aetrix verify that LM3405XMK/NOPB is sourced from the original manufacturer or authorized distributors?
All LM3405XMK/NOPB 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 LM3405XMK/NOPB meets industry standards.
7.What is the process for return or replacement of LM3405XMK/NOPB?
All LM3405XMK/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM3405XMK/NOPB, 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 LM3405XMK/NOPB part is unused and in its original packaging.
Return procedure for LM3405XMK/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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