LM3409MY/NOPB - 10V PFET Buck LED Controller | 1A | 10-HVSSOP
MPN: LM3409MY/NOPB ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $1.92 | $1.92 |
| 10 | $1.71 | $17.10 |
| 100 | $1.45 | $145.00 |
| 500 | $1.23 | $615.00 |
| 1,000 | $1.04 | $1,040.00 |
LM3409MY/NOPB Overview
A PFET buck controller is a type of LED driver that uses a high-side P-channel power MOSFET and a continuous-conduction buck topology. Compared to N-channel buck controllers, PFET controllers require no bootstrap or charge pump to drive the high-side switch, which simplifies the schematic and reduces component count. The LM3409 family belongs to the broader category of switch-mode LED drivers within power management ICs, sitting alongside LED-driver controller ICs that target architectural, automotive, and industrial lighting.
Key features include wide 6V-42V input range, high-side differential current sense with adjustable threshold, fast output enable/disable control, and analog plus PWM dimming capability. The IC supports cycle-by-cycle battery current limiting and thermal shutdown, and its thermally enhanced exposed-pad HVSSOP package enables high-power LED strings to be driven reliably without external heatsinking at moderate currents.
The LM3409 uses a constant-off-time (TOFF) control architecture with a single external resistor programming TOFF, simplifying EMI design and providing predictable switching frequency. The TOFF control method inherently regulates average inductor current, yielding excellent line and load regulation across VIN variations and LED forward-voltage spread. The 10-pin HVSSOP (MY) package provides a PowerPAD exposed lead frame for low thermal resistance.
Typical applications include architectural LED lighting, signage, automotive interior/exterior lighting (using LM3409-Q1), and industrial machine vision illumination. The wide VIN range also supports PoE-powered LED fixtures and emergency-lighting converters. Ensure the differential sense amplifier is configured with an external resistor divider matched to the desired ILED; do not exceed 65V transient on the VLT1 pin per the datasheet absolute maximums.
Drop-in alternatives for LM3409MY/NOPB — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Variants in this series
Same-series models that are drop-in compatible with LM3409MY/NOPB (same form factor and footprint) — differing in Package, Topology, Dimming Method, Operating Temperature.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
LM3409MY
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
LM3409MYX/NOPB
✅ Drop-In📋 Reference alternative (not in catalog)
LM3409QMY/NOPB
✅ Drop-In📋 Reference alternative (not in catalog)
LM3409HVMY/NOPB
✅ Drop-In ⚠️ Specs Unverified✓ In Stock
$1.4 / Unit
View Datasheet →LM3409QHV MY/NOPB
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
LM3409MY/NOPB Maximum Ratings & Electrical Characteristics
| Topology | Step-Down (Buck), PFET controller |
| Input Voltage Range | 6 V to 42 V |
| Number of Outputs | 1 |
| Output Current | Externally set by sense resistor (typical 1 A) |
| Dimming Method | Analog, PWM |
| Switching Control | Constant Off-Time |
| Current Sense | High-side differential, adjustable threshold |
| Package | 10-pin HVSSOP (MY) with PowerPAD |
| Mounting Type | Surface Mount |
| Operating Temperature | -40C to +125C |
| MSL Level | 1 |
| RoHS Status | Compliant |
| Lead Free | Yes |
| AEC-Q100 Qualification | Not qualified (LM3409-Q1 variant is qualified) |
| Special Features | Fast output enable/disable, thermally enhanced shell, HVSSOP exposed pad, FT-232 compatibility |
LM3409MY/NOPB Pin Configuration
| Pin 1 | VLT1 — Input voltage sense 1 / input |
| Pin 2 | VLT2 — Input voltage sense 2 / input |
| Pin 3 | VCC — Internal regulator output / bypass |
| Pin 4 | EN/PWM — Enable and PWM dimming input |
| Pin 5 | GND — Ground |
| Pin 6 | GATE — PFET gate drive output |
| Pin 7 | IADJ — Current adjust / sense reference |
| Pin 8 | TOFF — Off-time programming |
| Pin 9 | NC — Not connected (per datasheet) |
| Pin 10 | NC — Not connected (per datasheet) |
| Pin 11 | EP — Exposed thermal pad (PowerPAD) - connect to GND |
Typical Applications
LM3409MY/NOPB is suitable for 6 applications: Architectural LED Lighting, Automotive Interior Lighting, Industrial Machine Vision Illumination, LED Signage and Channel Letters, PoE-Powered LED Lighting, Emergency and Backup Lighting.
Architectural LED Lighting
Drives 1-5A high-brightness LED strings from 12V-36V architectural bus supplies. The LM3409MY/NOPB's 6V-42V VIN and high-side differential current sense enable grounded heat-sink LED mounting, critical for architectural fixtures where reflections on chassis are visible. The PFET buck topology minimizes component count: only an inductor, PFET, sense resistor, and input/output capacitors are needed. PWM dimming via the EN pin supports 0-10V dimmer interfaces with a small coupling network, allowing direct integration with architectural dimming controls.
Recommended
Automotive Interior Lighting
The LM3409-Q1 (AEC-Q100 qualified variant) drives interior cabin LED strings such as map lights, dome lights, and ambient lighting from 12V automotive rails. The wide VIN up to 42V tolerates load-dump transients of 12V automotive systems. High-side current sense eliminates ground-loop issues, important when LED modules are physically remote from the controller PCB. PWM dimming at 200Hz-1kHz via EN pin provides smooth brightness control without flicker. The automotive-qualified part is LM3409QMY/NOPB.
Recommended
Industrial Machine Vision Illumination
Provides constant-current drive for high-power LED arrays used in machine vision and inspection systems. The LM3409MY/NOPB's fast output enable/disable capability supports strobe-mode operation at kHz rates for high-speed machine vision. High-side differential current sense provides precise average current matching across multiple LED strings, critical for uniform illumination. The wide VIN range accepts 24V industrial power buses, and the HVSSOP exposed pad enables reliable operation at full duty cycle.
Recommended
LED Signage and Channel Letters
Drives LED channel-letter modules and signage strips from 24V power supplies commonly used in commercial signage. The constant-off-time control architecture provides predictable switching frequency for low-EMI operation, important in commercial environments with sensitive electronics. High-side current sense eliminates the need for low-side ground wiring, simplifying installation and improving reliability. PWM dimming supports daylight sensors for automatic brightness adjustment, reducing power consumption and extending LED lifetime.
Recommended
PoE-Powered LED Lighting
Powers high-brightness LED fixtures from Power-over-Ethernet (PoE) 48V rails. The LM3409HV variant supports up to 75V VIN, providing adequate headroom for 48V PoE input. Constant-current regulation maintains uniform LED brightness across the full PoE voltage range. The HVSSOP exposed pad enables efficient thermal dissipation in sealed PoE fixture enclosures. High-side differential current sense accommodates remote LED strings mounted at distance from the controller.
Recommended
Emergency and Backup Lighting
Drives emergency LED fixtures from battery-backed 12V-24V systems with wide VIN up to 42V for battery voltage variation. The LM3409MY/NOPB's high-side current sense enables grounded heat-sink mounting, critical for safety-approved emergency fixtures. Fast PWM dimming response supports daylight-harvesting and occupancy-sensor interfaces. The wide VIN range tolerates battery droop during discharge, maintaining LED brightness throughout the backup period. Constant-off-time control yields predictable EMI for safety-critical environments.
Recommended
Recommended Products Summary
Engineering reference data for LM3409MY/NOPB — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | LM3409MY | LM3409MYX/NOPB | LM3409QMY/NOPB | LM3409HVMY/NOPB | LM3409QHV MY/NOPB |
|---|---|---|---|---|---|---|
| Package | 10-HVSSOP (MY) | 10-HVSSOP (MY) - same | 10-HVSSOP (MY) - same | 10-HVSSOP (MY) - same | 10-HVSSOP (MY) - same | 10-HVSSOP (MY) - same |
| Brand | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments |
| Input Voltage Range | 6 V to 42 V | 6 V to 42 V | 6 V to 42 V | 6 V to 42 V | 6 V to 75 V | 6 V to 75 V |
| AEC-Q100 Qualified | No | No | No | Yes | No | Yes |
| Topology | PFET Buck | PFET Buck | PFET Buck | PFET Buck | PFET Buck | PFET Buck |
| Dimming Method | Analog + PWM | Analog + PWM | Analog + PWM | Analog + PWM | Analog + PWM | Analog + PWM |
| Current Sense | High-side differential | High-side differential | High-side differential | High-side differential | High-side differential | High-side differential |
Key Differentiators
- PFET buck topology eliminates bootstrap/charge pump (vs LM3402HVMM (NFET controller))
- High-side differential current sense eliminates low-side RSENSE (vs LM3402HVMM (low-side sense))
- Wide 6V-42V VIN covers both industrial and commercial applications (vs LM3409HV (75V VIN))
Design Notes
The 10-pin HVSSOP package with exposed PowerPAD requires a copper pad of minimum 0.15 square inch on top layer and at least 4 thermal vias to the inner/ground plane. At 1A LED current and 24V (VSIL) with VOUT = 12V, the LM3409MY/NOPB controller itself dissipates approximately 0.3W (mainly gate charge and quiescent), but the external PFET dissipates (VSIL - VOUT) * ILED = 12W. The PFET requires its own thermal management; the LM3409 itself stays cool. Estimated: VSIL=24V, VOUT=12V, ILED=1A, PFET dissipation = 12W; PFET package thermal resistance determines pinout performance.
Place the input capacitor as close as possible to the VSIL and GND pins to minimize switching-loop inductance. Use a 1uF X7R ceramic in parallel with a 10uF electrolytic for input bypassing. The differential sense resistor (RSNS) should use a 4-wire Kelvin connection to the high-side LED current path; trace resistance can otherwise offset the 200mV reference and degrade current accuracy. Keep the TOFF programming resistor close to the TOFF pin to minimize noise pickup.
Do not exceed the absolute maximum VLT1 pin rating, exceeding 65V transient (refer to datasheet for exact transient limit) or the LM3409HV variant must be selected for 48V PoE applications. The PWM dimming duty cycle should not exceed 100:1 if driver overshoot on the LED string is observed; lower inductance or add a snubber. The IADJ pin should be left open for default 200mV reference or driven externally for analog dimming - do not tie IADJ to VSIL.
Compliance Information
RoHS compliant and lead-free per TI product page. Not AEC-Q100 qualified - choose LM3409QMY/NOPB-Q1 for automotive applications.
