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Analog Devices Inc. LT3942EUFD#TRPBF
- Part No.:
- LT3942EUFD#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- LED Drivers
- Package:
- 28-WFQFN Exposed Pad
- Datasheet:
-
LT3942EUFD#TRPBF.pdf
- Description:
- IC LED DRIVER RGLTR PWM 2A 28QFN
- Quantity:
- Payment:
- Shipping:
Inventory:4,521
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Product details
Overview
LT3942EUFD#TRPBF from Analog Devices is a monolithic 4-switch synchronous buck-boost DC/DC converter with integrated constant-voltage and constant-current regulation, supporting both voltage regulator and high-precision LED driver applications. It operates across 3V–36V input and 0V–36V output ranges, delivers up to 2A peak switch current, achieves ±1.5% output voltage regulation and ±3% output current regulation, and enables flicker-free 5000:1 external PWM dimming - used in automotive headlight modules requiring seamless VIN-to-VOUT transition.
For engineers reviewing the LT3942EUFD#TRPBF datasheet, LT3942EUFD#TRPBF pinout, LT3942EUFD#TRPBF application, or LT3942EUFD#TRPBF equivalent, key selection considerations include its 4-switch single-inductor architecture enabling buck/boost/buck-boost operation without mode switching noise, AEC-Q100 qualification for automotive temperature range (–40°C to 125°C), and dual regulation capability with independent ISP/ISN current sensing and FB voltage feedback.
Technical Context
The LT3942EUFD#TRPBF implements Analog Devices' proprietary peak-buck/peak-boost current mode control, dynamically selecting between four operating states based on PVIN/PVOUT ratio to ensure smooth, low-noise transitions across buck (PVIN ≫ VOUT), buck-boost (PVIN ≈ VOUT), and boost (PVIN ≪ VOUT) regions. Its internal error amplifiers drive VC to set inductor current thresholds for both buck and boost comparators (A1/A2), while separate ISP/ISN and FB inputs enable simultaneous current and voltage loop regulation.
It integrates four N-channel DMOS power switches (150 mΩ RDS(on) each), dual bootstrap drivers (BST1/BST2), and a programmable oscillator (300 kHz–2 MHz via RT pin) with spread-spectrum option (SYNC/SPRD pin). Fault protection includes open/short LED detection via FB and ISP/ISN thresholds, overvoltage lockout (OVLO), and thermal shutdown - all coordinated through dedicated FAULT and SS pins.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3V to 36V - supports wide-input industrial and automotive battery systems including 12V/24V rails and cold-crank transients. |
| Output Voltage Range | 0V to 36V - enables direct LED string drive without external boost stage and flexible CV/CV+CC power supply design. |
| Switch Current Limit | 2.2A typical peak - sets maximum inductor current during buck or boost operation, limiting power stage stress under load or fault. |
| Output Voltage Regulation | ±1.5% over temperature - ensures stable reference for precision voltage rails or LED forward voltage compensation. |
| Output Current Regulation | ±3% over temperature - guarantees accurate LED current matching across strings in multi-lamp lighting systems. |
| Dimming Ratio | 5000:1 external PWM - eliminates visible flicker at low brightness in automotive DRLs and adaptive headlights. |
| Switching Frequency | 300 kHz to 2 MHz - allows optimization of magnetics size vs EMI; synchronized externally or operated with 25% triangle spread spectrum. |
Pinout & Package
LT3942EUFD#TRPBF is housed in a 28-lead (4 mm × 5 mm) plastic QFN package with exposed thermal pad (Pin 29 = GND), θJA = 43°C/W, θJC = 3.4°C/W. The package supports high-power density layout with low-inductance ground path via soldered exposed pad.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| PVIN, VIN | Power input and bias supply | PVIN connects to main input rail; VIN powers internal circuitry and INTVCC LDO - decoupling required separately for low-noise gate drive. |
| ISP / ISN | Current sense differential inputs | Measures voltage across external sense resistor (RIS) to regulate LED or load current; Kelvin connection mandatory for ±3% accuracy. |
| FB | Voltage feedback input | Sets output voltage by regulating to 1.00V reference; also triggers open/short LED fault when VFB exceeds 0.95V or falls below 0.25V. |
| CTRL | Current threshold programming | Analog input scaling ISP/ISN full-scale threshold from 0 mV to 100 mV - enables dimming curve shaping and current derating. |
| PWM / RP | Dimming interface | PWM accepts digital signal for external dimming; RP sets internal PWM frequency - tied to GND for LED driver mode or VREF for voltage regulator. |
| SW1 / SW2 | Buck and boost switch nodes | SW1 connects to buck-side inductor node; SW2 to boost-side - both require minimized trace area to reduce EMI and ringing. |
| BST1 / BST2 | Bootstrap supplies | Drive high-side N-FET gates; require ceramic capacitors (e.g., 0.1 µF) from BSTx to respective SWx pins. |
| FAULT | Open-drain fault indicator | Pulled low on open LED (VFB > 0.95V & V(ISP−ISN) < 10 mV), short LED (VFB < 0.25V), or OVLO - requires external pull-up for system-level fault reporting. |
Key Features
| Feature | Design Value |
|---|---|
| 4-switch single-inductor topology | Eliminates need for separate buck/boost ICs or complex multi-rail designs; enables seamless mode transition without audible noise or output glitch. |
| AEC-Q100 qualified (Grade E) | Validated for automotive ambient temperatures (–40°C to +125°C junction), including thermal cycling, HTOL, and ESD testing per automotive reliability standards. |
| Dual regulation loops (CV + CC) | Simultaneously regulates output voltage via FB and load current via ISP/ISN - essential for LED drivers with variable Vf and voltage regulators with precise current limiting. |
| Flicker-free 5000:1 external PWM dimming | Supports high-frequency (>1 kHz) digital dimming without visible artifacts - meets UNECE R149 and SAE J2359 requirements for adaptive front lighting. |
| Programmable soft-start and fault response | SS pin capacitor sets ramp time; resistor from SS to VREF selects hiccup/latch-off/keep-running behavior during LED faults - configurable per system safety policy. |
Applications
| Automotive Adaptive Headlights | Industrial High-Bay LED Drivers |
|---|---|
Use Scenario: Dynamic beam shaping using multiple independently controlled LED strings in vehicle headlamp assemblies. IC Role / Device Role / Timing Role: Constant-current LED driver with 5000:1 PWM dimming and open/short LED fault reporting via FAULT pin. Use Value: Enables pixel-level illumination control with ±3% current matching across strings and seamless buck-boost operation during 6V–16V battery transients. | Use Scenario: High-efficiency 48V DC-powered LED fixtures for warehouse and factory lighting. IC Role / Device Role / Timing Role: Buck-boost voltage regulator delivering regulated 42V output from varying 36V–57V input bus. Use Value: Maintains stable light output despite input ripple and line variation; 93% efficiency at 12W reduces thermal load in enclosed fixtures. |
| Automotive Interior Ambient Lighting | Medical Diagnostic Display Backlight |
Use Scenario: RGBW LED modules for customizable cabin lighting with smooth color mixing and low-noise dimming. IC Role / Device Role / Timing Role: Multi-channel constant-current source with independent CTRL-based current scaling per channel. Use Value: Achieves flicker-free dimming down to 0.02% brightness using external PWM, meeting IEC 62471 photobiological safety requirements. | Use Scenario: High-contrast, low-flicker backlight for surgical monitors requiring Class I medical EMC compliance. IC Role / Device Role / Timing Role: Low-EMI buck-boost LED driver with 25% triangle spread spectrum and synchronized switching. Use Value: Reduces radiated emissions by >10 dBµV/m in 30–1000 MHz band - simplifies system-level EMC filtering and certification. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar buck-boost LED driver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3789EUF#PBF | Requires external MOSFETs; no integrated current regulation; only CV mode; no ISP/ISN sensing or FAULT reporting. | Suitable for high-current DC/DC conversion but not direct LED current control; lacks built-in LED protection logic. | Select when designing custom high-power (>5A) buck-boost converters with discrete FETs and external current sensing. |
| LM34927QMH/NOPB | Fixed 2.2MHz frequency; only boost-only topology; max 40V input; no buck-boost capability; no AEC-Q100 rating. | Limited to step-up LED drivers with fixed Vout; unsuitable for automotive VIN-to-VOUT crossover applications. | Select for cost-sensitive, non-automotive boost-only LED drivers where input always remains below output voltage. |
Compared with LTC3789EUF#PBF and LM34927QMH/NOPB, the LT3942EUFD#TRPBF uniquely integrates 4-switch buck-boost power stage, dual CV/CC regulation, AEC-Q100 qualification, and comprehensive LED fault handling - making it the only single-chip solution for automotive-grade adaptive lighting with seamless mode transition.
Availability
LT3942EUFD#TRPBF is available at Aetrix Electronics and suitable for automotive lighting, industrial LED drivers, and medical display backlighting requiring stable component supply, long-term lifecycle support, and AEC-Q100-compliant performance.
Supply support for LT3942EUFD#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, Inc. is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving industrial, automotive, communications, and healthcare markets.
The LT3942EUFD#TRPBF belongs to Analog Devices' Power by Linear™ family of high-efficiency, high-reliability DC/DC converters designed specifically for demanding automotive and industrial LED lighting and power regulation applications.
FAQ
What is the operating temperature range for the LT3942EUFD#TRPBF?
The LT3942EUFD#TRPBF is rated for –40°C to +125°C junction temperature and is AEC-Q100 qualified (Grade E). This specification ensures reliable operation in automotive engine compartments and industrial environments where ambient temperatures exceed 85°C. The device includes thermal shutdown protection that activates above 150°C to prevent permanent damage, and its θJC of 3.4°C/W enables efficient heat transfer to the PCB ground plane via the exposed pad.
Does the LT3942EUFD#TRPBF support both constant-voltage and constant-current regulation simultaneously?
Yes, the LT3942EUFD#TRPBF supports concurrent constant-voltage (CV) and constant-current (CC) regulation using independent feedback paths: FB pin regulates output voltage to 1.00V, while ISP/ISN differential inputs regulate load current with ±3% accuracy. In LED driver mode, CV loop maintains safe VOUT headroom; in voltage regulator mode, CC loop acts as precise programmable current limit. Both loops are active and coordinated internally - no external multiplexing or mode switching is required.
How does the LT3942EUFD#TRPBF handle LED open-circuit and short-circuit faults?
The LT3942EUFD#TRPBF detects LED open-circuit when VFB > 0.95V and V(ISP−ISN) < 10 mV, and short-circuit when VFB < 0.25V. Upon detection, it pulls the open-drain FAULT pin low and enters a user-configurable fault response (hiccup, latch-off, or keep-running) determined by the resistor connected from SS to VREF. Fault status is updated only during PWM high time and latched during low time - ensuring deterministic behavior in dimmed operation.
Can the LT3942EUFD#TRPBF be synchronized to an external clock?
Yes, the LT3942EUFD#TRPBF supports external frequency synchronization via the SYNC/SPRD pin. When driven with a clean CMOS/TTL clock signal (300 kHz–2 MHz), the internal oscillator locks to the external frequency with minimal jitter. This capability enables EMI reduction in dense PCB layouts and timing coordination across multiple converters in multi-string LED systems - critical for automotive lighting modules requiring synchronized dimming across zones.
What is the purpose of the CTRL pin on the LT3942EUFD#TRPBF?
The CTRL pin on the LT3942EUFD#TRPBF programs the full-scale current sense threshold at the ISP/ISN inputs. Applying a voltage from 0.25V to 2.0V scales the regulated current linearly from 0 mV to 100 mV across RIS, enabling analog dimming, thermal derating, or dynamic current adjustment. For example, 1.0V on CTRL yields ~50 mV full-scale threshold, corresponding to half the maximum LED current. Tying CTRL to VREF (2.0V) sets full-scale at 100 mV - the default for maximum current regulation in the LT3942EUFD#TRPBF.
LT3942EUFD#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 28-WFQFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Type:
- DC DC Regulator
- Topology:
- Step-Down (Buck), Step-Up (Boost)
- Internal Switch(s):
- Yes
- Number of Outputs:
- 1
- Voltage - Supply (Min):
- 3V
- Voltage - Supply (Max):
- 36V
- Voltage - Output:
- 0V ~ 36V
- Current - Output / Channel:
- 2A
- Frequency:
- 300kHz ~ 2MHz
- Dimming:
- Analog, PWM
- Applications:
- General Purpose, Lighting
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- Automotive
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 28-QFN (4x5)
LT3942EUFD#TRPBF FAQ
1.How can I place an order for LT3942EUFD#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3942EUFD#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 LT3942EUFD#TRPBF reliable?
The price and inventory of LT3942EUFD#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3942EUFD#TRPBF is usually 5 days.
3.What payment methods are accepted for LT3942EUFD#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3942EUFD#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3942EUFD#TRPBF?
LT3942EUFD#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3942EUFD#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 LT3942EUFD#TRPBF?
For technical support, including LT3942EUFD#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3942EUFD#TRPBF requirements.
6.How does Aetrix verify that LT3942EUFD#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT3942EUFD#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 LT3942EUFD#TRPBF meets industry standards.
7.What is the process for return or replacement of LT3942EUFD#TRPBF?
All LT3942EUFD#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3942EUFD#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 LT3942EUFD#TRPBF part is unused and in its original packaging.
Return procedure for LT3942EUFD#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LT3942EUFD#TRPBF Tags
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BCR420UE6433HTMA1
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CL2N8-G
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