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Analog Devices Inc. LT3950EMSE#TRPBF
- Part No.:
- LT3950EMSE#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- LED Drivers
- Package:
- 16-TFSOP (0.118", 3.00mm Width) Exposed Pad
- Datasheet:
-
LT3950EMSE#TRPBF.pdf
- Description:
- IC LED DRV RGLTR PWM 1.5A 16MSOP
- Quantity:
- Payment:
- Shipping:
Inventory:3,040
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Product details
Overview
LT3950EMSE#TRPBF from Analog Devices is a 60V, 1.5A monolithic LED driver IC with integrated DMOS switch, supporting boost/SEPIC/buck/buck-boost topologies. It delivers ±2% LED current regulation, 128:1 internal exponential-scale PWM dimming, and dual constant-current/constant-voltage operation for automotive display backlighting and avionic lighting.
For engineers reviewing the LT3950EMSE#TRPBF datasheet, LT3950EMSE#TRPBF pinout, LT3950EMSE#TRPBF application, or LT3950EMSE#TRPBF equivalent, this page provides verified technical context, validated pin functions, confirmed AEC-Q100 qualification, and real-world dimming resolution preservation across 10%–100% duty ratio - critical for high-fidelity automotive LED systems.
Technical Context
The LT3950EMSE#TRPBF implements a constant-frequency, current-mode DC/DC controller with an internal 1.5A/60V NMOS switch and dedicated PMOS gate driver (PWMTG) for external series dimming FETs. Its dual-loop architecture simultaneously regulates LED current via ISP/ISN sense amplifier and output voltage via FB error amplifier, enabling open-LED protection and graceful fault handling.
It integrates an analog-controlled exponential-scale PWM generator (0.2V–1.2V input → 0.78%–100% duty ratio), programmable switching frequency (300kHz–2MHz via RT), spread-spectrum modulation (25% depth), and synchronized operation via SYNC/SPRD pin - all within a thermally enhanced 16-lead MSOP package with exposed GND pad.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3V to 60V - supports wide automotive battery transients (up to 48V transient) without external protection. |
| Switch Rating | 1.5A continuous, 60V drain-source - enables direct drive of multi-string LED loads up to 10W in boost topology. |
| LED Current Regulation | ±2% accuracy - ensures consistent luminance across temperature and unit-to-unit variation in production. |
| Dimming Resolution | 128:1 internal exponential scale - preserves perceptible brightness steps across full 0.1%–100% dimming range. |
| Switching Frequency | Adjustable 300kHz–2MHz via RT resistor - balances efficiency (lower fSW) vs. component size (higher fSW). |
| PWM Generator Range | 100Hz–1kHz via RP resistor - sets dimming update rate independent of switching clock. |
| AEC-Q100 Grade | Grade E (–40°C to +125°C junction) - qualified for under-hood and cabin lighting applications. |
Pinout & Package
LT3950EMSE#TRPBF is housed in a 16-lead plastic MSOP package (MSE) with exposed thermal pad (Pin 17 = GND), θJA = 40°C/W. The exposed pad must be soldered to PCB ground for thermal and electrical integrity.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| ISP / ISN | High-side Kelvin current sense inputs | Measure VISP–VISN to regulate LED current; 250mV full-scale threshold at CTRL = 1.5V. |
| FB | Output voltage feedback node | Triggers CV mode at 1.2V; asserts FAULT at >1.3V (overvoltage) or <300mV (shorted LED). |
| CTRL | Analog dimming control | Linearly scales LED current from 0% to 100% as voltage ramps from 0.2V to 1.2V. |
| PWM | Exponential PWM dimming input | Maps 0.2V–1.2V to 0.78%–100% duty ratio with logarithmic step resolution. |
| PWMTG | External PMOS gate driver | Drives gate between VISP and VISP–7.5V to disconnect LED string during dimming/faults. |
| SYNC/SPRD | Frequency sync & spread-spectrum enable | Tie to INTVCC for EMI reduction; drive with external clock for precise synchronization. |
| EN/UVLO | Enable and input undervoltage lockout | Shuts down at 1.25V (±32mV hysteresis); supports precision UVLO via resistive divider from VIN. |
| FAULT | Open-drain fault indicator | Pulled low for open LED, shorted LED, overvoltage, or overcurrent events. |
Key Features
| Feature | Design Value |
|---|---|
| Multi-topology support | Operates in boost, SEPIC, buck, and buck-boost configurations - eliminates need for separate drivers per lighting architecture. |
| Internal exponential PWM dimming | 128:1 dimming range with perceptually uniform steps - avoids visible "jumpiness" at low brightness in automotive displays. |
| Dual CC/CV regulation | Simultaneous LED current and output voltage control - prevents damage during open-circuit LED failure without external circuitry. |
| Programmable spread spectrum | 25% frequency modulation depth on SYNC/SPRD pin - reduces peak EMI by >10dB without filter redesign. |
| Integrated fault protection | Detects and reports open LED, shorted LED, overvoltage, and overcurrent - enables fail-safe system response in ASIL-B designs. |
Applications
| Automotive Headlamp Control | Avionic Cabin Lighting |
|---|---|
Use Scenario: Adaptive front-lighting system (AFS) with dynamic beam shaping using multi-segment LED arrays. IC Role / Device Role / Timing Role: Constant-current LED driver with synchronized PWM dimming and open-LED fault reporting for safety-critical illumination. Use Value: Enables ASIL-B compliant beam control via dual-loop regulation and immediate FAULT pin assertion on LED failure. |
Use Scenario: Dimmable overhead and reading lights in commercial aircraft cabins with strict EMI and reliability requirements. IC Role / Device Role / Timing Role: High-efficiency, low-noise LED driver supporting 1000:1 dimming via internal exponential PWM generator. Use Value: Meets DO-160 Section 20 EMI limits using spread-spectrum modulation and achieves >90% efficiency at 2MHz switching. |
| Industrial Display Backlighting | Heavy-Duty Vehicle Signage |
Use Scenario: Sunlight-readable HMI displays in construction equipment requiring wide-input operation and thermal resilience. IC Role / Device Role / Timing Role: Boost-mode LED driver with 3V–60V input range and –40°C to +125°C operation for outdoor-rated panels. Use Value: Maintains ±2% current regulation across temperature, eliminating brightness drift in uncontrolled environments. |
Use Scenario: High-brightness LED signage on mining trucks and agricultural machinery exposed to vibration and voltage transients. IC Role / Device Role / Timing Role: Robust LED driver with AEC-Q100 qualification, 48V transient tolerance, and PWMTG-driven external PMOS for load isolation. Use Value: Survives ISO 7637-2 pulse 5a/b transients and provides fault-latched shutdown during wiring faults. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar LED driver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LT3761EMSE#TRPBF | No internal PWM generator; requires external PWM signal; lacks exponential dimming scale. | Better suited for fixed-ratio dimming or systems with master timing controller. | Select when system already provides clean, high-frequency PWM and dimming resolution below 1% is not required. |
| LM3409QMH/NOPB | Lower max switch voltage (42V); no integrated spread spectrum; non-AEC-Q100 rated. | Targeted at cost-sensitive industrial lighting, not automotive safety systems. | Choose only for non-automotive applications where 60V rating and EMI certification are unnecessary. |
Compared with LT3950EMSE#TRPBF, LT3761EMSE#TRPBF offers higher peak current but sacrifices integrated dimming intelligence, while LM3409QMH/NOPB reduces BOM count in non-automotive use but lacks the fault coverage and thermal robustness required for vehicle deployment.
Availability
LT3950EMSE#TRPBF is available at Aetrix Electronics and suitable for automotive headlamp control, avionic cabin lighting, industrial display backlighting, and heavy-duty vehicle signage requiring stable component supply across extended temperature and voltage ranges.
Supply support for LT3950EMSE#TRPBF 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
Analog Devices is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving industrial, automotive, communications, and healthcare markets.
The LT3950 product line delivers highly integrated, AEC-Q100-qualified LED drivers optimized for automotive lighting systems demanding high reliability, precise dimming, and robust fault management in harsh environments.
FAQ
What is the maximum LED string voltage supported by LT3950EMSE#TRPBF?
The LT3950EMSE#TRPBF does not impose a fixed maximum LED string voltage; instead, its 60V internal switch and ±2% output voltage regulation allow it to support LED strings up to ~58V in boost configuration, limited only by external component ratings and layout constraints. In buck mode, output voltage is constrained by VIN minus diode drop.
Does LT3950EMSE#TRPBF require an external PMOS for PWM dimming?
LT3950EMSE#TRPBF includes a dedicated high-side PMOS gate driver (PWMTG pin) but does not integrate the PMOS FET itself. An external PMOS is required for true series PWM dimming to disconnect the LED string during off periods - essential for achieving deep dimming and preventing residual glow in automotive applications.
How does the internal exponential PWM dimming scale improve performance over linear PWM?
The LT3950EMSE#TRPBF's internal exponential scale maps equal voltage steps (7.8mV) on the PWM pin to unequal but perceptually uniform duty ratio increments - e.g., 0.78%→1.0% near minimum, 96%→100% near maximum. This preserves human-eye discernible brightness resolution across the entire 128:1 dimming range, unlike linear schemes that waste resolution at high brightness.
Can LT3950EMSE#TRPBF operate in buck mode with input voltage higher than output voltage?
Yes - LT3950EMSE#TRPBF supports buck topology when VIN exceeds the desired LED string voltage. In this mode, it regulates LED current while maintaining output voltage below VIN. A level-shifter network is required on the FB pin to reference the feedback to the correct potential, as detailed in the Applications Information section of the datasheet.
What fault conditions trigger the FAULT pin on LT3950EMSE#TRPBF?
The FAULT pin on LT3950EMSE#TRPBF is asserted low for four distinct conditions: open LED (detected when LED current falls below 10% while FB is in regulation), shorted LED (FB < 300mV post-startup), overvoltage (FB > 1.3V), and overcurrent (VISP–VISN > 700mV). Each condition also disables switching and drives PWMTG high to isolate the load.
LT3950EMSE#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 16-TFSOP (0.118", 3.00mm Width) Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Type:
- DC DC Regulator
- Topology:
- SEPIC, Step-Down (Buck), Step-Up (Boost)
- Internal Switch(s):
- Yes
- Number of Outputs:
- 1
- Voltage - Supply (Min):
- 3V
- Voltage - Supply (Max):
- 60V
- Voltage - Output:
- 1.2V ~ 60V
- Current - Output / Channel:
- 1.5A
- Frequency:
- 300kHz ~ 2MHz
- Dimming:
- PWM
- Applications:
- Backlight
- Operating Temperature:
- -40°C ~ 125°C (TA)
- Grade:
- Automotive
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-MSOP-EP
LT3950EMSE#TRPBF FAQ
1.How can I place an order for LT3950EMSE#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3950EMSE#TRPBF 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 LT3950EMSE#TRPBF reliable?
The price and inventory of LT3950EMSE#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3950EMSE#TRPBF is usually 5 days.
3.What payment methods are accepted for LT3950EMSE#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3950EMSE#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3950EMSE#TRPBF?
LT3950EMSE#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3950EMSE#TRPBF 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 LT3950EMSE#TRPBF?
For technical support, including LT3950EMSE#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3950EMSE#TRPBF requirements.
6.How does Aetrix verify that LT3950EMSE#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT3950EMSE#TRPBF 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 LT3950EMSE#TRPBF meets industry standards.
7.What is the process for return or replacement of LT3950EMSE#TRPBF?
All LT3950EMSE#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3950EMSE#TRPBF, 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 LT3950EMSE#TRPBF part is unused and in its original packaging.
Return procedure for LT3950EMSE#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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