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Texas Instruments LM3405AXMKE/NOPB
- Part No.:
- LM3405AXMKE/NOPB
- Manufacturer:
- Texas Instruments
- Category:
- LED Drivers
- Package:
- SOT-23-6 Thin, TSOT-23-6
- Datasheet:
-
LM3405AXMKE/NOPB.pdf
- Description:
- IC LED DRV RGLTR PWM 1A TSOT23-6
- Quantity:
- Payment:
- Shipping:
Inventory:1,463
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Product details
Overview
LM3405AXMKE/NOPB from Texas Instruments is a 1.6-MHz, 1-A constant-current buck LED driver IC in MSOP-PowerPAD™-8 package, featuring internal compensation, 0.205-V feedback reference, 360-mΩ NMOS switch, and EN/DIM pin for PWM dimming. It drives up to five 3.7-V HB-LEDs in series for industrial lighting and flashlight applications.
For engineers reviewing the LM3405AXMKE/NOPB datasheet, LM3405AXMKE/NOPB pinout, LM3405AXMKE/NOPB application, or LM3405AXMKE/NOPB equivalent, key selection criteria include input voltage range (3–22 V), thermal performance (RθJA = 55.3°C/W), shutdown current (0.3 µA), switching frequency stability (1.2–1.9 MHz), and FB pin bias current (10–250 nA).
Technical Context
The LM3405AXMKE/NOPB implements current-mode control with internal compensation, enabling stable regulation without external loop components. Its 1.6-MHz fixed-frequency operation supports compact ceramic inductors and capacitors while maintaining cycle-by-cycle current limiting and UVLO with 440-mV hysteresis.
It uses an internal NMOS switch with RDS(ON) = 360 mΩ (typ.) at VBOOST–VSW = 3 V and delivers regulated LED current via feedback at the FB pin referenced to 0.205 V. The EN/DIM pin provides both enable control and PWM dimming capability across 100 Hz–5 kHz.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VIN Range | 3 V to 22 V - supports wide-input industrial and automotive LED systems without pre-regulation |
| Switching Frequency | 1.2–1.9 MHz (typ. 1.6 MHz) - enables use of sub-2.2-µH SMT inductors and low-ESR ceramic output caps |
| Feedback Voltage (VFB) | 0.188–0.220 V (typ. 0.205 V) - sets LED current with ±5% accuracy using single external resistor |
| RDS(ON) | 360–700 mΩ - determines conduction loss and thermal rise in MSOP-PowerPAD package |
| Quiescent Current | 2.8 mA (operating), 0.3 µA (shutdown) - minimizes standby power in battery-powered flashlights |
| UVLO Threshold | Rising: 2.74–2.95 V; Falling: 1.9–2.3 V - prevents erratic startup during brownout conditions |
| Thermal Resistance | RθJA = 55.3°C/W - defines maximum power dissipation limit (≈1.8 W) before thermal shutdown at 125°C ambient |
Pinout & Package
LM3405AXMKE/NOPB is housed in an 8-pin MSOP-PowerPAD™ package (3.00 mm × 3.00 mm) with exposed thermal pad (DAP) soldered to PCB ground for enhanced heat dissipation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| BOOST (Pin 4) | Bootstrap gate drive supply | Charged via external diode/capacitor to generate ≥2.5 V above SW for NMOS turn-on; must stay ≤5.5 V above SW |
| GND (Pins 2, 7) | Signal and power ground | Common return for feedback network, thermal pad (DAP), and catch diode cathode; critical for noise immunity and thermal path |
| FB (Pin 1) | Current-sense feedback input | Monitors voltage across external sense resistor; regulates LED current by holding at 0.205 V ±1.7% |
| EN/DIM (Pin 8) | Enable and PWM dimming control | Logic-high (>1.8 V) enables operation; toggling at 100 Hz–5 kHz dims LEDs with minimal current overshoot |
| VIN (Pin 6) | Main input supply | Accepts 3–22 V; requires local 1-µF ceramic bypass capacitor to GND for EMI suppression and transient response |
| SW (Pin 5) | Switch node | Connects to inductor, catch diode anode, and bootstrap capacitor; swings between VIN and –VD1 during operation |
| NC (Pin 3) | No connection | Unbonded pad - must remain unconnected and unpopulated on PCB |
Key Features
| Feature | Design Value |
|---|---|
| Internally compensated current-mode control | Eliminates need for external compensation network; ensures stable regulation across 3–22 V input and 200 mA–1 A load |
| 1.6-MHz fixed-frequency operation | Reduces inductor size to <2.2 µH and enables full-ceramic BOM with no electrolytic capacitors |
| 0.205-V precision feedback reference | Enables accurate LED current setting (±5%) with standard 1% resistors; minimizes I²R loss in sense resistor |
| Integrated 360-mΩ NMOS switch | Supports 1-A continuous LED current in MSOP-PowerPAD package with RθJA = 55.3°C/W |
| EN/DIM pin with 100-Hz–5-kHz PWM dimming | Provides flicker-free brightness control without external MOSFET drivers or timing components |
Applications
| Industrial Lighting | LED Flashlights |
|---|---|
Use Scenario: High-bay LED luminaires powered from 12–24 VDC industrial bus with thermal constraints. IC Role / Device Role / Timing Role: Constant-current buck regulator delivering 1 A to 5-series HB-LED string with internal compensation and thermal shutdown. Use Value: Enables compact, fanless fixture design using only ceramic passives and achieves >88% efficiency at 12 VIN/3.7 VLED×5. | Use Scenario: Rechargeable handheld flashlight requiring long runtime, instant on/off, and adjustable brightness. IC Role / Device Role / Timing Role: Primary LED driver with ultra-low shutdown current (0.3 µA) and fast EN/DIM response (<100 µs). Use Value: Extends Li-ion battery life by >30% versus discrete solutions; supports smooth 10:1 dimming ratio via PWM without color shift. |
| LED Lightbulbs | Automotive Interior Lighting |
Use Scenario: Retrofit A19 LED bulb operating from rectified AC line (12–20 V DC bus) with space-limited E26 base. IC Role / Device Role / Timing Role: Compact buck controller driving 4–5 white LEDs in series with integrated thermal foldback. Use Value: Fits within 12-mm diameter PCB area; maintains constant lumen output over temperature via 0.205-V reference stability. | Use Scenario: Map light or footwell illumination powered from 12 V vehicle battery with cold-crank tolerance. IC Role / Device Role / Timing Role: Robust LED driver surviving 4.5–22 V input transients and providing UVLO hysteresis (440 mV) for clean startup. Use Value: Eliminates need for external LDO or supervisor IC; operates down to 2.74 V during cranking without dropout. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar constant-current buck LED driver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM3405AMKE/NOPB | SOT-6 package (2.90 mm × 1.60 mm); lower current rating (400 mA max); RθJA = 182.9°C/W | Space-constrained portable devices where 1-A output not required; higher thermal resistance limits continuous power | Select when board area is critical and LED current ≤400 mA; verify thermal margin under worst-case ambient |
| TPS61061DRVR | Boost topology; 40-V output capability; 0.5-A switch; 1.2-MHz switching; no internal compensation | Required for single-cell Li-ion (2.7–4.2 V) powering >3.3-V LED strings; needs external compensation and feedback divider | Choose for low-input-voltage boost applications; avoid for 3–22 V buck scenarios due to topology mismatch |
Compared with LM3405AXMKE/NOPB, the LM3405AMKE/NOPB offers identical functionality in a smaller footprint but reduced current and thermal capability, while the TPS61061DRVR serves different input/output voltage relationships and requires additional external components for stability.
Availability
LM3405AXMKE/NOPB is available at Aetrix Electronics and suitable for industrial lighting, LED flashlights, and automotive interior lighting requiring stable component supply, long-term lifecycle support, and consistent parametric performance across production batches.
Supply support for LM3405AXMKE/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 leader specializing in analog, embedded processing, and power management technologies with over 50 years of innovation in high-reliability IC design.
The LM3405A product line delivers highly integrated, thermally optimized constant-current LED drivers for space- and efficiency-sensitive applications including portable lighting and industrial solid-state illumination.
FAQ
What is the maximum LED string voltage supported by LM3405AXMKE/NOPB?
The LM3405AXMKE/NOPB supports up to five 3.7-V high-brightness LEDs in series, yielding a maximum output voltage of approximately 18.7 V (5 × 3.7 V + 0.205 V). This assumes VIN ≥ 22 V and accounts for the 0.205-V FB reference. Operation beyond this requires verifying that VOUT = (n × VF) + VFB stays within the device's duty-cycle and thermal limits. The LM3405AXMKE/NOPB itself does not regulate output voltage directly-it regulates current, so string voltage depends entirely on LED forward characteristics.
Can LM3405AXMKE/NOPB operate from a 5-V USB source?
Yes, LM3405AXMKE/NOPB operates from 3 V to 22 V, making it compatible with 5-V USB sources. At 5 V input, it can drive up to two 3.7-V LEDs in series (VOUT ≈ 7.6 V), provided the duty cycle remains feasible and thermal limits are observed. Efficiency drops at low VIN due to higher duty cycle and increased conduction loss; typical efficiency at 5 V/350 mA is ~82%. The LM3405AXMKE/NOPB UVLO ensures reliable startup above 2.74 V.
How does the EN/DIM pin function in LM3405AXMKE/NOPB?
The EN/DIM pin on LM3405AXMKE/NOPB serves dual roles: applying >1.8 V enables operation, while applying a logic square wave (100 Hz–5 kHz) enables PWM dimming. There is a ~100-µs delay from EN/DIM high to full LED current establishment. The pin draws only 0.01 µA, allowing direct MCU GPIO control without buffering. Floating the pin disables the device; it must never exceed VIN + 0.3 V. The LM3405AXMKE/NOPB does not support analog dimming-only digital PWM via this pin.
What is the purpose of the BOOST pin on LM3405AXMKE/NOPB?
The BOOST pin on LM3405AXMKE/NOPB supplies gate drive voltage to the internal NMOS switch. It must be ≥2.5 V above SW during turn-on and ≤5.5 V above SW to ensure reliable switching and minimize RDS(ON). A bootstrap capacitor (C3) and diode (D2) form the charge pump. In the standard configuration, C3 charges from VIN through D2; during SW low-time, VBOOST ≈ VIN − VD2 + VD1. Proper BOOST voltage is essential for achieving the specified 360-mΩ RDS(ON) and 1-A output capability in the LM3405AXMKE/NOPB.
Does LM3405AXMKE/NOPB require external compensation components?
No, LM3405AXMKE/NOPB features fully internal compensation for its current-mode control loop. No external capacitors or resistors are needed to stabilize regulation-only the mandatory external components: input capacitor, output capacitor, inductor, catch diode, feedback resistor, and bootstrap capacitor/diode. This simplifies layout, reduces BOM count, and guarantees stability across all recommended operating conditions (3–22 V input, –40°C to 125°C junction). The LM3405AXMKE/NOPB datasheet confirms internal compensation in both Features and Detailed Description sections.
LM3405AXMKE/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):
- 22V
- Voltage - Output:
- -
- 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
LM3405AXMKE/NOPB FAQ
1.How can I place an order for LM3405AXMKE/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM3405AXMKE/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 LM3405AXMKE/NOPB reliable?
The price and inventory of LM3405AXMKE/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM3405AXMKE/NOPB is usually 5 days.
3.What payment methods are accepted for LM3405AXMKE/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM3405AXMKE/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM3405AXMKE/NOPB?
LM3405AXMKE/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM3405AXMKE/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 LM3405AXMKE/NOPB?
For technical support, including LM3405AXMKE/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM3405AXMKE/NOPB requirements.
6.How does Aetrix verify that LM3405AXMKE/NOPB is sourced from the original manufacturer or authorized distributors?
All LM3405AXMKE/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 LM3405AXMKE/NOPB meets industry standards.
7.What is the process for return or replacement of LM3405AXMKE/NOPB?
All LM3405AXMKE/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM3405AXMKE/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 LM3405AXMKE/NOPB part is unused and in its original packaging.
Return procedure for LM3405AXMKE/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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