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Texas Instruments LM3405XMKX/NOPB
- Part No.:
- LM3405XMKX/NOPB
- Manufacturer:
- Texas Instruments
- Category:
- LED Drivers
- Package:
- SOT-23-6 Thin, TSOT-23-6
- Datasheet:
-
LM3405XMKX/NOPB.pdf
- Description:
- IC LED DRV RGLTR PWM 1A TSOT23-6
- Quantity:
- Payment:
- Shipping:
Inventory:5,205
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Product details
Overview
LM3405XMKX/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 NMOS switch, and EN/DIM pin for PWM dimming. It drives up to five high-brightness LEDs in series and supports input voltages from 3 V to 15 V, making it suitable for portable LED flashlights and industrial lighting systems.
For engineers reviewing the LM3405XMKX/NOPB datasheet, LM3405XMKX/NOPB pinout, LM3405XMKX/NOPB application, or LM3405XMKX/NOPB equivalent, key selection criteria include regulated current accuracy (±8.5% over temperature), thermal shutdown at 165°C, UVLO with 440-mV hysteresis, and compatibility with ceramic output capacitors due to 1.6-MHz switching frequency.
Technical Context
The LM3405XMKX/NOPB uses current-mode control with internal compensation and fixed 1.6-MHz oscillator, enabling stable regulation without external loop compensation. Its cycle-by-cycle current limit (2 A typical) and overcurrent protection (328 mV FB threshold) operate independently of feedback loop dynamics.
Boost voltage generation relies on external bootstrap capacitor and diode, requiring VBOOST–VSW between 2.5 V and 5.5 V for proper NMOS gate drive. The EN/DIM pin provides both enable control and PWM dimming interface with 100-µs startup delay and 100 Hz–5 kHz usable frequency range.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VFB | 0.205 V nominal; sets LED current via external resistor (IF = VFB/R1) with ±8.5% variation over –40°C to 125°C |
| fSW | 1.6 MHz typical; enables use of small ceramic inductors & capacitors, reducing board area and EMI filter complexity |
| RDS(ON) | 300 mΩ max at VBOOST–VSW = 3 V; limits conduction loss at 1-A load to ≤300 mW |
| IQ (shutdown) | 0.3 µA typical at VIN = 5 V; supports ultra-low-power standby in battery-powered LED flashlights |
| UVLO threshold | 2.95 V rising / 2.3 V falling; 440-mV hysteresis prevents oscillation during non-monotonic input ramp-up |
| Thermal shutdown | 165°C junction activation; disables switch until TJ drops to ~150°C, protecting against sustained overload |
| EN/DIM logic threshold | 1.8 V enable / 0.4 V shutdown; supports direct connection to microcontroller GPIO or dedicated PWM source |
Pinout & Package
LM3405XMKX/NOPB is housed in a 6-pin SOT-6 (DDC) package measuring 2.90 mm × 1.60 mm, with exposed thermal pad for enhanced power dissipation (RθJA = 182.9°C/W).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - BOOST | Bootstrap voltage supply | Drives NMOS gate; requires external capacitor to SW; must maintain 2.5–5.5 V above SW for full RDS(ON) performance |
| 2 - GND | Signal and power ground | Reference for FB divider and internal circuits; bottom resistor of feedback network must be placed adjacent to this pin |
| 3 - FB | Current-sense feedback input | Monitors LED string cathode voltage; regulates IF by holding at 0.205 V; sensitive to PCB layout parasitics |
| 4 - EN/DIM | Enable and PWM dimming control | Logic-high (>1.8 V) enables operation; toggling at 100 Hz–5 kHz dims LED brightness; floating state disables device |
| 5 - VIN | Main input supply | Accepts 3–15 V; requires local bypass capacitor; powers internal circuitry and supplies BOOST charging current |
| 6 - SW | Switch node | Connects to inductor, catch diode anode, and BOOST capacitor; swings from near-GND to VIN minus RDS(ON)×IL |
Key Features
| Feature | Design Value |
|---|---|
| Internally compensated current-mode control | Eliminates need for external compensation network; ensures stable regulation across 3–15 V input and 0.2–1 A output current |
| 0.205-V precision feedback reference | Minimizes power loss in current-setting resistor; enables accurate LED current programming with standard 1% tolerance resistors |
| 1.6-MHz fixed-frequency operation | Reduces required inductor size to <1.5 µH and output capacitance to <10 µF, supporting compact PCB layouts |
| Cycle-by-cycle current limiting | Protects internal NMOS switch under short-circuit or overcurrent transients by limiting peak switch current to 2 A typical |
| Thermal shutdown with hysteresis | Prevents thermal runaway by disabling switching at 165°C and resuming only after junction cools to ~150°C |
Applications
| Portable LED Flashlights | Industrial Panel Lighting |
|---|---|
|
Use Scenario: Handheld illumination tool powered by single Li-ion cell (3.0–4.2 V) with adjustable brightness. IC Role / Device Role / Timing Role: Constant-current buck regulator controlling 3-series white LEDs at 1 A, using EN/DIM for user-adjustable PWM dimming. Use Value: Delivers >85% efficiency at 3.7 VLED × 3 + 0.205 V, with 0.3 µA shutdown current extending battery life between uses. |
Use Scenario: DIN-rail mounted control panel with status indicators requiring consistent luminance across ambient temperatures. IC Role / Device Role / Timing Role: Fixed-current driver powering 5-series high-brightness LEDs from 12-V DC rail, leveraging thermal shutdown for reliability in enclosed enclosures. Use Value: Maintains ±8.5% current accuracy from –40°C to 125°C, eliminating visible brightness drift during thermal cycling. |
| Automotive Interior Lighting | Architectural Accent Lighting |
|
Use Scenario: Map light or dome light in 12-V vehicle system with cold-crank immunity down to 6 V. IC Role / Device Role / Timing Role: Buck LED driver operating from unregulated automotive supply, using UVLO hysteresis to prevent flicker during engine start. Use Value: Starts reliably at 2.95 V and remains active down to 2.3 V, avoiding dropout during transient brownouts. |
Use Scenario: Low-profile linear LED strip for retail display cabinets powered from 15-V centralized supply. IC Role / Device Role / Timing Role: High-efficiency current source driving long LED strings with minimal heat generation in thermally constrained spaces. Use Value: 300-mΩ RDS(ON) limits conduction loss to <300 mW at 1 A, reducing heatsink requirements and enabling plastic housing designs. |
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 |
|---|---|---|---|
| LM3404MHX/NOPB | Higher 1.6-A current capability; 500-kHz switching frequency; HTSSOP-8 package with thermal pad | Better suited for higher-power LED arrays requiring >1 A; lower frequency increases inductor size but reduces EMI | Select when output current >1 A or thermal performance is critical; not pin-compatible with LM3405XMKX/NOPB |
| TPS61165DRVR | Boost topology; 40-V output capability; integrated 2-A switch; 1.2-MHz switching | Supports LED strings exceeding input voltage (e.g., 5×3.7 V from 5-V supply); requires different external component set | Choose for boost-based designs where VIN < VLED×n; incompatible topology prevents direct substitution |
Compared with LM3405XMKX/NOPB, LM3404MHX/NOPB offers higher current and better thermal handling in larger package, while TPS61165DRVR enables higher-voltage LED strings via boost architecture-neither is pin-compatible, and topology or current rating differences require schematic revision.
Availability
LM3405XMKX/NOPB is available at Aetrix Electronics and suitable for portable LED flashlights, industrial panel lighting, and automotive interior lighting requiring stable component supply with guaranteed long-term sourcing.
Supply support for LM3405XMKX/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 specializing in analog and embedded processing technologies, with leadership in power management ICs and LED driver solutions.
The LM3405XMKX/NOPB belongs to TI's constant-current buck LED driver product line, designed specifically for high-efficiency, compact, and thermally robust illumination systems in portable and industrial environments.
FAQ
What is the recommended minimum and maximum value for the current-setting resistor R1 in LM3405XMKX/NOPB applications?
The LM3405XMKX/NOPB requires R1 to set LED current via IF = 0.205 V / R1. To stay within its 1-A output capability and ensure stable operation, R1 must be ≥0.205 Ω (for 1 A) and ≤1.025 Ω (for 200 mA minimum). Values outside this range risk current regulation failure or thermal overload. Standard 1% metal-film resistors are recommended for accuracy and stability.
Can LM3405XMKX/NOPB drive more than five LEDs in series?
No-LM3405XMKX/NOPB is specified to drive up to five high-brightness LEDs in series at 1 A, assuming ~3.7 V forward voltage per LED (totaling ~18.5 V + 0.205 V). With maximum VIN = 15 V, the output voltage cannot exceed VIN – VSW drop, limiting practical string length. Attempting six LEDs would violate the device's output voltage headroom and cause regulation loss or shutdown.
How does the EN/DIM pin function during PWM dimming, and what is its timing behavior?
The EN/DIM pin on LM3405XMKX/NOPB serves dual purpose: logic-high (>1.8 V) enables operation, while PWM signals (100 Hz–5 kHz) modulate LED brightness by rapidly enabling/disabling the internal switch. Each enable transition incurs ~100 µs delay before full LED current is established, limiting minimum off-time and defining the upper usable frequency bound.
What thermal considerations apply to LM3405XMKX/NOPB in continuous 1-A operation?
In continuous 1-A operation at VIN = 12 V and VLED = 15 V, LM3405XMKX/NOPB dissipates ~3 W. With RθJA = 182.9°C/W, junction temperature rise exceeds safe limits without PCB copper thermal relief. Use of 2-in² 2-oz copper pour under the exposed pad is essential; thermal shutdown activates at 165°C to prevent damage.
Is LM3405XMKX/NOPB compatible with ceramic output capacitors, and why?
Yes-LM3405XMKX/NOPB is fully compatible with ceramic output capacitors due to its 1.6-MHz switching frequency, which ensures sufficient control-loop bandwidth and transient response. Ceramic capacitors provide low ESR, reduce output ripple, and eliminate electrolytic aging concerns-critical for long-life LED lighting applications where reliability is paramount.
LM3405XMKX/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
LM3405XMKX/NOPB FAQ
1.How can I place an order for LM3405XMKX/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM3405XMKX/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 LM3405XMKX/NOPB reliable?
The price and inventory of LM3405XMKX/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM3405XMKX/NOPB is usually 5 days.
3.What payment methods are accepted for LM3405XMKX/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM3405XMKX/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM3405XMKX/NOPB?
LM3405XMKX/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM3405XMKX/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 LM3405XMKX/NOPB?
For technical support, including LM3405XMKX/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM3405XMKX/NOPB requirements.
6.How does Aetrix verify that LM3405XMKX/NOPB is sourced from the original manufacturer or authorized distributors?
All LM3405XMKX/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 LM3405XMKX/NOPB meets industry standards.
7.What is the process for return or replacement of LM3405XMKX/NOPB?
All LM3405XMKX/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM3405XMKX/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 LM3405XMKX/NOPB part is unused and in its original packaging.
Return procedure for LM3405XMKX/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LM3405XMKX/NOPB Tags
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