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Analog Devices Inc. LT3942JUFD#TRPBF
- Part No.:
- LT3942JUFD#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- LED Drivers
- Package:
- 28-WFQFN Exposed Pad
- Datasheet:
-
LT3942JUFD#TRPBF.pdf
- Description:
- IC LED DRIVER RGLTR PWM 2A 28QFN
- Quantity:
- Payment:
- Shipping:
Inventory:3,886
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Product details
Overview
LT3942JUFD#TRPBF from Analog Devices is a monolithic 4-switch synchronous buck-boost DC/DC converter with integrated constant-voltage and constant-current regulation, designed for automotive-grade LED driver and voltage regulator applications. It supports 3V–36V input and 0V–36V output, delivers up to 2A peak switch current, operates from 300kHz to 2MHz, and features ±1.5% output voltage regulation and ±3% output current regulation.
For engineers reviewing the LT3942JUFD#TRPBF datasheet, LT3942JUFD#TRPBF pinout, LT3942JUFD#TRPBF application, or LT3942JUFD#TRPBF equivalent, key selection criteria include its AEC-Q100 qualification, seamless buck/buck-boost/boost mode transition, 5000:1 external PWM dimming capability, and fault reporting for open/short LED conditions.
Technical Context
The LT3942JUFD#TRPBF implements a proprietary peak-buck/peak-boost current-mode control architecture that directly senses inductor current across internal N-channel DMOS switches to enable smooth, low-noise transitions between buck, buck-boost, and boost operating regions. Its dual-loop regulation supports independent voltage (FB) and current (ISP/ISN) feedback paths with dedicated error amplifiers (EA1/EA2) and programmable thresholds.
It integrates four power switches (A–D), two bootstrap drivers (BST1/BST2), a 3.6V INTVCC linear regulator, 2V VREF reference, and digital fault logic that latches FAULT during open LED (VFB > 0.95V & V(ISP−ISN) < 10mV) or short LED (VFB < 0.25V) events. Switching frequency is set via RT resistor or synchronized externally via SYNC/SPRD pin.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3V to 36V - supports wide automotive battery range including cold-crank (4.5V) and load-dump (36V) transients. |
| Output Voltage Range | 0V to 36V - enables direct drive of multi-LED strings without external boost pre-regulator. |
| Switching Frequency | 300kHz to 2MHz - adjustable via RT pin; allows EMI optimization and compact magnetics selection. |
| Output Current Regulation | ±3% accuracy - ensures consistent LED brightness across temperature and line variations. |
| Output Voltage Regulation | ±1.5% accuracy - maintains stable rail for sensitive analog or digital loads. |
| Peak Switch Current Limit | 2.5A typical - sets maximum inductor current to prevent saturation and thermal overload. |
| Operating Junction Temp | –40°C to +150°C - qualified per AEC-Q100 Grade 1, suitable for under-hood automotive lighting. |
Pinout & Package
LT3942JUFD#TRPBF is housed in a 28-lead 4mm × 5mm plastic QFN package (UFD) with exposed thermal pad (Pin 29 = GND). The package supports high-power dissipation (θJC = 3.4°C/W) and is optimized for automotive thermal reliability.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| PVIN, VIN | Power input and bias supply rails | PVIN connects to main input source; VIN powers internal circuitry and INTVCC regulator - requires separate ceramic bypassing. |
| ISP / ISN | High-accuracy current sense differential inputs | Measures voltage drop across external sense resistor (RIS) for LED current regulation; supports Kelvin connection. |
| FB | Voltage loop feedback input | Regulates output voltage to 1.00V reference; also enables open/short LED fault detection via threshold monitoring. |
| CTRL | Current sense threshold programming | Analog input (0.25V–2V) sets full-scale ISP–ISN regulation voltage from 0mV to 100mV linearly. |
| PWM / RP | Dimming control interface | PWM accepts external digital signal or analog voltage for internal PWM dimming; RP sets internal dimming frequency (up to 5000:1 ratio). |
| FAULT | Open-drain fault status output | Pulled low during open LED, short LED, or overvoltage events; updated only during PWM high state and latched. |
| SS | Soft-start timing and fault mode selection | Capacitor-to-ground sets soft-start ramp time; resistor-to-VREF configures fault response (hiccup/latch-off/keep-running). |
Key Features
| Feature | Design Value |
|---|---|
| 4-switch single-inductor topology | Eliminates need for separate buck and boost stages - reduces BOM count, PCB area, and EMI sources. |
| Flicker-free spread spectrum | 25% triangle modulation on internal oscillator - lowers peak EMI without affecting dimming performance. |
| Integrated 3.6V INTVCC regulator | Supplies gate drivers and control logic from VIN - removes need for external bias rail in most designs. |
| AEC-Q100 Grade 1 qualification | Validated for automotive ambient temperatures up to +150°C - meets stringent reliability requirements for headlamp and DRL systems. |
| Programmable fault response | Three SS-pin configurations (hiccup/latch-off/keep-running) allow system-level safety strategy alignment. |
Applications
| Automotive Headlamp Driver | Industrial Constant-Current Supply |
|---|---|
Use Scenario: Driving high-brightness white LED arrays in adaptive front-lighting systems (AFS) with input voltage varying from 6V (cold crank) to 16V (running). IC Role / Device Role / Timing Role: Primary buck-boost LED driver providing precise constant-current regulation, PWM dimming, and real-time fault reporting. Use Value: Seamless mode transition avoids output glitches during battery transients; ±3% current accuracy ensures consistent lumen output across temperature. | Use Scenario: Powering precision LED-based optical sensors in factory automation equipment requiring stable current over 0–36V output range. IC Role / Device Role / Timing Role: Voltage-regulated current source with programmable dimming and overtemperature protection. Use Value: 5000:1 external PWM dimming enables fine-grained intensity control; AEC-Q100 qualification ensures long-term reliability in harsh industrial environments. |
| Automotive Rear Lighting | General-Purpose Buck-Boost Regulator |
Use Scenario: Driving brake/tail/turn LED strings in vehicles where input voltage may dip below nominal 12V during engine start. IC Role / Device Role / Timing Role: Constant-current LED driver with open/short LED detection and FAULT pin reporting to vehicle CAN bus controller. Use Value: Fault latching during PWM low state enables diagnostic logging; ±1.5% voltage regulation stabilizes auxiliary circuits powered from same rail. | Use Scenario: Generating regulated 5V/3.3V rails from variable input sources such as USB PD, PoE, or battery packs with wide voltage ranges. IC Role / Device Role / Timing Role: Synchronous buck-boost voltage regulator supporting input above, below, or equal to output. Use Value: Single-inductor architecture simplifies design vs. discrete buck+boost solutions; 93% efficiency at 12V/1A reduces thermal management burden. |
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 | External MOSFET controller (no integrated switches); requires 4 external FETs and gate drivers. | Lacks integrated current regulation and LED-specific fault logic; suited for higher-power (>5A) custom designs. | Select when higher output current or thermal separation is required; not drop-in compatible due to different pinout and control scheme. |
| LM34927QMH/NOPB | Fixed-frequency 2-switch buck-boost controller; no constant-current regulation; no AEC-Q100 rating. | Designed for general-purpose DC/DC conversion only; lacks ISP/ISN sensing, PWM dimming, and LED fault protection. | Choose for cost-sensitive non-automotive applications where LED driving is not required; requires external current-sense amplifier for LED use. |
Compared with LTC3789EUF#PBF and LM34927QMH/NOPB, the LT3942JUFD#TRPBF provides fully integrated switching, native LED current regulation, automotive qualification, and unified fault reporting - reducing total solution size by ~40% and eliminating 12+ external components in typical LED driver layouts.
Availability
LT3942JUFD#TRPBF is available at Aetrix Electronics and suitable for automotive lighting, industrial LED power supplies, and wide-input DC/DC regulation requiring stable component supply, AEC-Q100 compliance, and long-term production continuity.
Supply support for LT3942JUFD#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. (ADI) is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving industrial, automotive, communications, and healthcare markets.
The LT3942 product line was developed specifically for high-reliability automotive and industrial LED lighting applications, combining robust 4-switch buck-boost topology with integrated current/voltage regulation and comprehensive fault management.
FAQ
What is the maximum output current capability of the LT3942JUFD#TRPBF?
The LT3942JUFD#TRPBF supports up to 2A peak switch current per internal MOSFET (A–D), enabling continuous LED current up to 1.5A depending on thermal design and layout. Its ±3% current regulation accuracy ensures stable light output across temperature and input voltage variations, making it suitable for demanding automotive headlamp applications where the LT3942JUFD#TRPBF is commonly deployed.
Does the LT3942JUFD#TRPBF support synchronization to an external clock?
Yes, the LT3942JUFD#TRPBF supports external frequency synchronization via the SYNC/SPRD pin. When driven with a clean CMOS clock signal between 300kHz and 2MHz, the device locks its internal oscillator to the external source - enabling EMI reduction through frequency dithering or deterministic noise placement in multi-rail systems. This capability is documented in the LT3942JUFD#TRPBF datasheet Section 8, Electrical Characteristics.
How does the LT3942JUFD#TRPBF handle LED open-circuit faults?
The LT3942JUFD#TRPBF detects open LED conditions when FB voltage exceeds 0.95V while ISP–ISN voltage falls below 10mV. Upon detection, it pulls the open-drain FAULT pin low and enters a user-configurable fault mode (hiccup, latch-off, or keep-running) based on the SS pin configuration. This behavior is active during PWM high states and latched during low states - ensuring reliable diagnostics in the LT3942JUFD#TRPBF's automotive lighting implementations.
Can the LT3942JUFD#TRPBF operate as a pure voltage regulator without LED current sensing?
Yes, the LT3942JUFD#TRPBF can be configured as a constant-voltage regulator by connecting the ISP and ISN pins together (or leaving them unconnected) and using only the FB feedback loop. In this mode, it provides ±1.5% output voltage regulation, input/output current monitoring via ISMON, and full protection features including overvoltage lockout (OVLO) and thermal shutdown - retaining all core functionality of the LT3942JUFD#TRPBF outside LED-specific functions.
What is the purpose of the PWMTG pin on the LT3942JUFD#TRPBF?
The PWMTG pin on the LT3942JUFD#TRPBF provides a buffered, inverted version of the PWM input signal to drive an external high-side PMOS transistor for PWM dimming. It swings from (PVOUT − 5V) to PVOUT, enabling efficient gate drive without level-shifting circuitry. When unused, PWMTG must be left floating - tying it to ground or VOUT will disrupt internal logic. This feature is integral to the LT3942JUFD#TRPBF's flicker-free dimming architecture.
LT3942JUFD#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 ~ 150°C (TJ)
- Grade:
- Automotive
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 28-QFN (4x5)
LT3942JUFD#TRPBF FAQ
1.How can I place an order for LT3942JUFD#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3942JUFD#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 LT3942JUFD#TRPBF reliable?
The price and inventory of LT3942JUFD#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3942JUFD#TRPBF is usually 5 days.
3.What payment methods are accepted for LT3942JUFD#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3942JUFD#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3942JUFD#TRPBF?
LT3942JUFD#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3942JUFD#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 LT3942JUFD#TRPBF?
For technical support, including LT3942JUFD#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3942JUFD#TRPBF requirements.
6.How does Aetrix verify that LT3942JUFD#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT3942JUFD#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 LT3942JUFD#TRPBF meets industry standards.
7.What is the process for return or replacement of LT3942JUFD#TRPBF?
All LT3942JUFD#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3942JUFD#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 LT3942JUFD#TRPBF part is unused and in its original packaging.
Return procedure for LT3942JUFD#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LT3942JUFD#TRPBF Tags
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BCR402RE6327HTSA1
Infineon Technologies
-
BCR430UXTSA2
Infineon Technologies
-
BCR420UE6433HTMA1
Infineon Technologies
-
BCR420UE6327HTSA1
Infineon Technologies
-
BCR421UE6327HTSA1
Infineon Technologies
-
LYT1604D-TL
Power Integrations
-
HV9910CLG-G
Microchip Technology
-
CL2N8-G
Microchip Technology
-
BCR420UW6-7
Diodes Incorporated
-
BCR421UW6-7
Diodes Incorporated
-
BCR420UFD-7
Diodes Incorporated
-
BCR421UFD-7
Diodes Incorporated
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