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Analog Devices Inc. LT3950JMSE#TRPBF
- Part No.:
- LT3950JMSE#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- LED Drivers
- Package:
- 16-TFSOP (0.118", 3.00mm Width) Exposed Pad
- Datasheet:
-
LT3950JMSE#TRPBF.pdf
- Description:
- IC LED DRV RGLTR PWM 1.5A 16MSOP
- Quantity:
- Payment:
- Shipping:
Inventory:1,612
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Product details
Overview
LT3950JMSE#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 lighting systems requiring robust open/short LED protection.
For engineers reviewing the LT3950JMSE#TRPBF datasheet, LT3950JMSE#TRPBF pinout, LT3950JMSE#TRPBF application, or LT3950JMSE#TRPBF equivalent, key selection criteria include AEC-Q100 qualification, 300kHz–2MHz programmable switching frequency, internal spread spectrum EMI reduction, PMOS gate driver (PWMTG), and 16-lead MSOP package with exposed thermal pad.
Technical Context
The LT3950JMSE#TRPBF implements a constant-frequency, current-mode DC/DC controller with dual-loop regulation: primary current-sense loop (ISP/ISN) for LED current control and secondary voltage-feedback loop (FB) for overvoltage/LED-open protection. Its internal 1.5A, 60V DMOS switch enables high-efficiency operation across multitopology configurations without external high-side switches.
It integrates an analog-controlled dimming path (CTRL pin, 0.2V–1.2V linear mapping to 0–250mV sense threshold) and two independent PWM dimming methods: external TTL-compatible PWM input (PWM pin) and internal 7-bit exponential-scale generator (RP-programmed 100Hz–1kHz frequency). Fault handling includes open/short LED detection, overcurrent (700mV ISP–ISN threshold), and FB overvoltage (1.3V) shutdown with open-drain FAULT reporting.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3V to 60V - supports wide automotive battery range including cold-crank and load-dump transients up to 48V. |
| Switch Rating | 1.5A, 60V DMOS - enables direct drive of high-brightness LED strings without external high-side switch in buck/boost modes. |
| LED Current Accuracy | ±2% - ensures consistent luminance across temperature and unit-to-unit variation in display backlighting. |
| Dimming Resolution | 128:1 internal exponential scale - preserves perceptual brightness resolution across full 0.1%–100% dimming range. |
| Switching Frequency | 300kHz to 2MHz - allows optimization for EMI (lower fSW) or compact magnetics (higher fSW). |
| Thermal Rating | J-grade: –40°C to +150°C junction - qualified per AEC-Q100 Grade 1 for under-hood automotive lighting. |
| Protection Features | Open/short LED, overvoltage (FB >1.3V), overcurrent (ISP–ISN >700mV), UVLO with hysteresis - eliminates need for external fault monitoring circuitry. |
Pinout & Package
LT3950JMSE#TRPBF is housed in a 16-lead plastic MSOP package with exposed thermal pad (Pin 17 = GND), optimized for thermal dissipation in space-constrained automotive modules. The exposed pad must be soldered to PCB ground plane for proper thermal and electrical performance.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| ISP / ISN | High-side Kelvin current sense inputs | Measure voltage drop across external RSENSE; enable precise 250mV-setpoint current regulation with offset control via CTRL pin. |
| FB | Output voltage feedback input | Enters CV mode when ≥1.2V; triggers FAULT at 1.3V (overvoltage) or <300mV (shorted LED); supports level-shifter networks in buck/buck-boost. |
| CTRL | Analog dimming control | Linearly scales LED current from 0% to 100% as voltage ramps from 0.2V to 1.2V; also accepts low-frequency PWM (≤1kHz). |
| PWM | Internal/external PWM dimming input | Accepts analog voltage (0.2–1.2V) for exponential dimming or digital signal (≥1.3V ON / ≤0.1V OFF) for direct PWM control. |
| PWMTG | PMOS gate driver output | Drives external high-side PMOS to disconnect LED string during PWM off-time or fault events; clamped to VISP − 7.5V max. |
| SYNC/SPRD | Frequency sync / spread-spectrum enable | Tied to INTVCC for EMI reduction; driven by external clock for precise synchronization (e.g., to camera shutter timing). |
| RT / RP | Switching / PWM frequency programming | RT sets fSW (300kHz–2MHz); RP sets internal PWM frequency (100Hz–1kHz); both use single resistors to GND. |
| FAULT | Open-drain fault indicator | Pulled low on open LED, short LED, overvoltage, or overcurrent; requires external pull-up to VIN or INTVCC. |
Key Features
| Feature | Design Value |
|---|---|
| Multitopology support | Operates in boost, SEPIC, buck, and buck-boost configurations - enables single IC solution for diverse LED voltage requirements (e.g., 12V input → 48V headlight or 5V input → 3.3V tail light). |
| AEC-Q100 Grade 1 qualification | Validated for –40°C to +150°C junction operation - meets automotive reliability standards for front-end lighting and interior ambient modules. |
| Integrated spread spectrum modulation | Reduces peak EMI by >10dB without external components - simplifies CISPR-25 Class 5 compliance in vehicle ECU designs. |
| Dual-loop CC/CV regulation | Prevents catastrophic failure during open-circuit LED faults by transitioning to voltage regulation before FAULT assertion - maintains system stability without external crowbar circuits. |
| Programmable UVLO with hysteresis | EN/UVLO threshold (1.25V typ.) with 32mV hysteresis - enables clean startup/shutdown sequencing aligned with vehicle battery management systems. |
Applications
| Automotive Headlights | Avionic Cabin Lighting |
|---|---|
Use Scenario: High-intensity LED arrays in adaptive driving beam (ADB) systems requiring precise current control and fast PWM dimming for dynamic light shaping. IC Role / Device Role / Timing Role: Constant-current LED driver with 2MHz switching and internal exponential PWM generator synchronized to camera frame rate via SYNC/SPRD pin. Use Value: Enables 128:1 dimming resolution while maintaining thermal stability at 150°C junction temperature - critical for sealed headlamp housings. | Use Scenario: Dimmable white LED strips in aircraft passenger service units (PSUs), operating from 28V DC aircraft bus with strict EMI limits. IC Role / Device Role / Timing Role: Boost-mode LED driver with spread spectrum enabled via SYNC/SPRD tied to INTVCC, delivering 90% efficiency at 10W output. Use Value: Meets DO-160 Section 20 radiated emissions requirements without added filtering - reduces BOM cost and board area. |
| Industrial Display Backlighting | Commercial Vehicle Signage |
Use Scenario: Large-format LCD backlights in outdoor kiosks exposed to wide ambient temperature swings (–40°C to +85°C). IC Role / Device Role / Timing Role: SEPIC topology driver providing stable 1.5A current despite input voltage sag during generator brownouts (down to 3V). Use Value: Maintains ±2% current accuracy across full temperature range - prevents visible luminance drift in sunlight-readable displays. | Use Scenario: Red/amber LED arrays in truck trailer brake lights and turn signals, powered from 12V/24V battery with load-dump transients up to 48V. IC Role / Device Role / Timing Role: Buck-mode driver with 60V switch rating and programmable UVLO to ignore brief transients while ensuring reliable startup after deep discharge. Use Value: Eliminates need for external TVS and pre-regulator - achieves IP67-compliant design with minimal component count. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar LED driver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM3409QMH/NOPB | 40V max input, 1.25A switch, no internal PWM generator, requires external MOSFET for high-side dimming | Lacks exponential dimming and integrated PWMTG - needs additional gate driver and PWM controller for comparable functionality | Choose LM3409QMH/NOPB only if lower input voltage (<40V) and discrete dimming control are acceptable trade-offs for cost-sensitive non-AEC-Q100 designs. |
| MAX20050ATP/V+T | AEC-Q100 Grade 1, 65V input, 2.2A switch, integrated I²C interface, but no internal exponential PWM generator | Supports digital configuration and diagnostics via I²C - adds flexibility but increases firmware complexity versus LT3950JMSE#TRPBF's analog simplicity | Select MAX20050ATP/V+T when system-level telemetry (e.g., LED health monitoring) justifies added software overhead and higher BOM cost. |
Compared with LM3409QMH/NOPB and MAX20050ATP/V+T, the LT3950JMSE#TRPBF uniquely combines AEC-Q100 qualification, integrated 128:1 exponential PWM, and dual CC/CV safety regulation in a single 16-pin MSOP - reducing design cycle time and layout risk for automotive lighting OEMs.
Availability
LT3950JMSE#TRPBF is available at Aetrix Electronics and suitable for automotive lighting, avionic cabin systems, industrial display backlighting, and commercial vehicle signage requiring stable component supply and long-term lifecycle support.
Supply support for LT3950JMSE#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 automotive, industrial, communications, and healthcare markets.
The LT3950 product line delivers highly integrated, AEC-Q100-qualified LED drivers targeting demanding automotive exterior and interior lighting applications where reliability, thermal robustness, and EMI control are critical.
FAQ
What is the maximum junction temperature rating for LT3950JMSE#TRPBF?
The LT3950JMSE#TRPBF is rated for –40°C to +150°C junction temperature and is AEC-Q100 Grade 1 qualified. This specification ensures reliable operation in under-hood automotive environments where ambient temperatures exceed 125°C. The exposed thermal pad (Pin 17) must be soldered to a PCB ground plane to maintain thermal resistance below θJA = 40°C/W and prevent derating above 125°C junction.
Does LT3950JMSE#TRPBF support buck-mode LED driving?
Yes, LT3950JMSE#TRPBF supports buck-mode operation, enabling step-down conversion from higher input voltages (e.g., 48V bus) to lower LED string voltages (e.g., 12V). In buck configuration, the FB pin requires a level-shifter network (e.g., NPN-based) to reference the regulated output voltage to ground, as described in the Applications Information section of the datasheet. The internal 1.5A, 60V switch handles full load current without external components.
How does the internal exponential PWM dimming work on LT3950JMSE#TRPBF?
The LT3950JMSE#TRPBF uses a 7-bit ADC to convert the analog voltage on the PWM pin (0.2V–1.2V) into a digital code, where each 7.8mV step changes the duty ratio exponentially. For example, a 7.8mV increment near 10% yields ~0.4% absolute change (9.6%→10%), while the same increment near 100% yields ~4% change (96%→100%). This preserves perceptual dimming resolution across the full range without requiring microcontroller-based logarithmic lookup tables.
Can LT3950JMSE#TRPBF operate with input voltage below 3V?
No, LT3950JMSE#TRPBF has a minimum specified input voltage of 3V per Absolute Maximum Ratings and Electrical Characteristics tables. Operation below 3V is not guaranteed and may result in unstable regulation, failure to initiate soft-start, or undefined behavior of the internal LDO (INTVCC). For sub-3V applications, consider alternative drivers such as the LT3965 or discrete controller solutions with external bias supplies.
What protection features does LT3950JMSE#TRPBF provide for LED fault conditions?
LT3950JMSE#TRPBF provides comprehensive LED fault protection: open LED detection (via FB pin voltage drop below 10% full-scale while in CV mode), shorted LED detection (FB <300mV), overvoltage (FB >1.3V), and overcurrent (ISP–ISN >700mV). All faults assert the open-drain FAULT pin low and disable switching; PWMTG is driven high to disconnect the LED string. No external fault logic is required.
LT3950JMSE#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 ~ 150°C (TA)
- Grade:
- Automotive
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-MSOP-EP
LT3950JMSE#TRPBF FAQ
1.How can I place an order for LT3950JMSE#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3950JMSE#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 LT3950JMSE#TRPBF reliable?
The price and inventory of LT3950JMSE#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3950JMSE#TRPBF is usually 5 days.
3.What payment methods are accepted for LT3950JMSE#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3950JMSE#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3950JMSE#TRPBF?
LT3950JMSE#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3950JMSE#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 LT3950JMSE#TRPBF?
For technical support, including LT3950JMSE#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3950JMSE#TRPBF requirements.
6.How does Aetrix verify that LT3950JMSE#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT3950JMSE#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 LT3950JMSE#TRPBF meets industry standards.
7.What is the process for return or replacement of LT3950JMSE#TRPBF?
All LT3950JMSE#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3950JMSE#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 LT3950JMSE#TRPBF part is unused and in its original packaging.
Return procedure for LT3950JMSE#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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