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Analog Devices Inc. LT3942HUFD#TRPBF
- Part No.:
- LT3942HUFD#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- LED Drivers
- Package:
- 28-WFQFN Exposed Pad
- Datasheet:
-
LT3942HUFD#TRPBF.pdf
- Description:
- IC LED DRIVER RGLTR PWM 2A 28QFN
- Quantity:
- Payment:
- Shipping:
Inventory:2,343
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Product details
Overview
LT3942HUFD#TRPBF from Analog Devices is a monolithic 4-switch synchronous buck-boost converter with integrated constant-voltage and constant-current regulation, designed for automotive-grade LED driver and voltage regulator applications. It supports 3V–36V input, 0V–36V output, ±1.5% output voltage regulation, ±3% output current regulation, and operates at 300kHz–2MHz switching frequency with spread-spectrum EMI reduction. Used in adaptive automotive lighting systems requiring seamless mode transition.
For engineers reviewing the LT3942HUFD#TRPBF datasheet, LT3942HUFD#TRPBF pinout, LT3942HUFD#TRPBF application, or LT3942HUFD#TRPBF equivalent, key selection criteria include its AEC-Q100 qualification, 28-pin QFN (4mm × 5mm) package with exposed thermal pad, dual regulation capability (CV/CC), 128:1 internal / 5000:1 external PWM dimming, and fault reporting for open/short LED conditions.
Technical Context
The LT3942HUFD#TRPBF implements a proprietary peak-buck/peak-boost current-mode control architecture that enables continuous conduction across buck, buck-boost, and boost regions without audible noise or output discontinuity. Its four N-channel DMOS switches are driven by integrated high-side gate drivers requiring only two external bootstrap capacitors.
It features independent ISP/ISN current sensing with programmable full-scale threshold (via CTRL pin), FB-based voltage loop with 1.00V reference, and dedicated FAULT pin reporting open LED (VFB > 0.95V & V(ISP−ISN) < 10mV), short LED (VFB < 0.25V), and overvoltage (VFB > 1.05V) events - all validated over −40°C to +150°C junction temperature.
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 stage. |
| Switching Frequency | 300kHz to 2MHz - adjustable via RT resistor; synchronizable externally or configurable for 25% triangle spread spectrum to reduce EMI peaks. |
| Output Regulation Accuracy | ±1.5% VOUT, ±3% IOUT - ensures stable illumination intensity and consistent power delivery under varying thermal/load conditions. |
| Operating Junction Temp | −40°C to +150°C - qualified per AEC-Q100 Grade H, suitable for under-hood automotive lighting modules. |
| Dimming Ratio | 5000:1 external PWM, 128:1 internal PWM - enables flicker-free, high-resolution brightness control in headlight DRL and matrix beam applications. |
| Fault Protection | Open/short LED detection with FAULT pin assertion and configurable SS-latch behavior - provides system-level safety compliance for ISO 26262 ASIL-B relevant functions. |
Pinout & Package
LT3942HUFD#TRPBF is housed in a 28-lead plastic QFN package (4mm × 5mm) with exposed thermal pad (Pin 29 = GND), θJA = 43°C/W, θJC = 3.4°C/W. The exposed pad must be soldered to PCB ground plane for thermal and electrical integrity.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| PVIN, VIN | Power input & bias supply rails | PVIN connects to main input source; VIN powers internal circuitry and INTVCC LDO - decoupling required on both pins for stability. |
| ISP / ISN | Differential current sense inputs | Kelvin-connected across external RIS to enable accurate LED current regulation with ±3% tolerance over temp. |
| FB | Voltage feedback input | Regulates output to 1.00V reference; triggers FAULT on open (VFB > 0.95V) or short (VFB < 0.25V) LED conditions. |
| CTRL | Current sense threshold programming | Analog input setting full-scale V(ISP−ISN) from 0mV to 100mV - enables dynamic current scaling for multi-zone lighting control. |
| PWMTG | High-side PMOS gate driver output | Drives external PMOS switch with rail-to-rail swing (PVOUT − 5V to PVOUT); enables true high-side PWM dimming with no low-side current path. |
| FAULT | Open-drain fault status output | Pulled low during open/short LED or overvoltage - requires external pull-up; status updated only during PWM high phase. |
| RT | Oscillator frequency set | Resistor-to-ground sets switching frequency from 300kHz to 2MHz - critical for EMI compliance and inductor size optimization. |
| SYNC/SPRD | Freq sync input / spread-spectrum enable | Ground = internal oscillator; INTVCC = 25% triangle spread spectrum; external clock = synchronization to system master clock. |
Key Features
| Feature | Design Value |
|---|---|
| 4-switch single-inductor topology | Enables seamless VIN-to-VOUT transition across buck/boost boundaries without mode-hopping artifacts or output ripple spikes. |
| AEC-Q100 Grade H qualification | Validated for −40°C to +150°C operation - meets automotive reliability requirements for front-end lighting and ADAS illumination subsystems. |
| Integrated 3.6V INTVCC LDO | Supplies internal logic and gate drivers from VIN; 40mA current limit and 120mV dropout at 10mA ensure robust startup under low-input conditions. |
| Programmable soft-start (SS) | Capacitor-to-ground sets ramp time; resistor-to-VREF configures fault response (hiccup/latch-off/keep-running) during LED faults. |
| Independent CV and CC regulation | Simultaneous voltage regulation (via FB) and current regulation (via ISP/ISN) - supports dual-role use as LED driver or general-purpose buck-boost regulator. |
| Spread-spectrum EMI reduction | 25% triangle modulation above base frequency reduces peak radiated emissions - simplifies EMC filter design in space-constrained automotive modules. |
Applications
| Automotive Adaptive Front Lighting | Industrial High-Bay LED Driver |
|---|---|
Use Scenario: Matrix LED headlight system with individually addressable segments for glare-free high-beam assist and cornering light. IC Role / Device Role / Timing Role: Primary LED current controller with per-string 128:1 internal PWM dimming and real-time open-circuit fault detection. Use Value: Enables ASIL-B compliant illumination control with <100ns fault response latency and seamless dimming across 0–100% duty cycle without color shift. | Use Scenario: 150W industrial LED fixture operating from 24VDC factory bus with 36V max input transient tolerance. IC Role / Device Role / Timing Role: Constant-current buck-boost regulator driving 12-series LED string with 32V output requirement. Use Value: Eliminates need for separate boost stage; achieves >93% efficiency at 2MHz switching while maintaining <10mV current ripple. |
| Automotive Interior Ambient Lighting | Medical Diagnostic Illumination |
Use Scenario: RGBW cabin lighting module requiring precise white-point tuning and smooth 0.02% dimming resolution. IC Role / Device Role / Timing Role: Multi-channel current source with independent CTRL pin programming per channel and synchronized PWM dimming. Use Value: Delivers 5000:1 external PWM dimming ratio with zero flicker, meeting IEC 62471 photobiological safety requirements. | Use Scenario: Ophthalmic imaging light source requiring stable, ripple-free 350mA output with rapid on/off sequencing. IC Role / Device Role / Timing Role: Precision constant-current driver with <1µs PWM-to-output propagation delay and <0.5% current drift over 8-hour operation. Use Value: Guarantees repeatable exposure intensity across imaging sessions; FAULT pin integration enables automatic lamp health monitoring. |
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 |
|---|---|---|---|
| LT3932EUFD#TRPBF | Single-output, non-synchronous boost-only topology; 60V max input; no buck-boost capability; no ISP/ISN current sense. | Limited to boost-only LED strings; unsuitable for VIN-above-VOUT or wide-input-range automotive applications. | Select only when output voltage always exceeds input and AEC-Q100 qualification is not required. |
| TPS92692QPWPRQ1 | Two-channel, current-mode boost controller; supports external MOSFETs; no integrated switches; 65V max input; no spread spectrum. | Requires external power stage; higher BOM count; lacks seamless buck-boost transition and integrated fault reporting. | Prefer for high-power (>200W), thermally isolated designs where discrete FET selection is mandatory. |
Compared with LT3932EUFD#TRPBF and TPS92692QPWPRQ1, the LT3942HUFD#TRPBF uniquely integrates 4-switch buck-boost conversion, AEC-Q100 qualification, and unified CV/CC regulation - reducing component count by 40% and enabling single-chip solutions for adaptive lighting systems requiring input voltage flexibility and functional safety support.
Availability
LT3942HUFD#TRPBF is available at Aetrix Electronics and suitable for automotive lighting, industrial LED drivers, and medical illumination systems requiring stable component supply, extended temperature operation, and AEC-Q100 compliance.
Supply support for LT3942HUFD#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 for precision instrumentation, industrial automation, and automotive electronics.
The LT3942HUFD#TRPBF belongs to Analog Devices' Power by Linear™ family of high-reliability DC/DC converters, engineered specifically for demanding automotive LED lighting applications requiring wide input range, precise current regulation, and robust fault handling.
FAQ
What is the maximum junction temperature rating for the LT3942HUFD#TRPBF?
The LT3942HUFD#TRPBF is rated for operation up to +150°C junction temperature and is qualified per AEC-Q100 Grade H. This specification is guaranteed across the full −40°C to +150°C operating junction temperature range, making it suitable for under-hood automotive environments where thermal stress is extreme. The device includes thermal shutdown protection that activates above this threshold to prevent permanent damage.
Does the LT3942HUFD#TRPBF support both constant-voltage and constant-current regulation simultaneously?
No - the LT3942HUFD#TRPBF operates in either constant-voltage (CV) mode using the FB pin or constant-current (CC) mode using the ISP/ISN differential inputs, but not both simultaneously in active regulation. However, it uses FB for CV regulation *and* for LED open/short fault detection during CC operation, providing dual-loop supervision. The LT3942HUFD#TRPBF's architecture allows seamless reconfiguration between modes via external component selection without changing the IC.
How is PWM dimming implemented on the LT3942HUFD#TRPBF?
The LT3942HUFD#TRPBF supports two independent PWM dimming methods: external digital PWM applied to the PWM pin (up to 5000:1 ratio), and internal analog-controlled PWM generated from a 1V–2V CTRL voltage (up to 128:1 ratio). The PWMTG pin provides a buffered, inverted gate drive signal for an external high-side PMOS switch, ensuring clean, low-jitter dimming with no shoot-through risk. Both methods are validated across the full −40°C to +150°C range.
What package type and thermal characteristics does the LT3942HUFD#TRPBF use?
The LT3942HUFD#TRPBF uses a 28-lead plastic QFN package measuring 4mm × 5mm with an exposed thermal pad (Pin 29 = GND). Its thermal resistance is θJA = 43°C/W and θJC = 3.4°C/W. The exposed pad must be soldered directly to a PCB ground plane with multiple thermal vias to achieve rated performance and maintain junction temperature within limits during 2A continuous operation.
Can the LT3942HUFD#TRPBF be synchronized to an external clock source?
Yes - the LT3942HUFD#TRPBF supports external frequency synchronization via the SYNC/SPRD pin. When driven with a TTL/CMOS-compatible clock signal between 300kHz and 2MHz, the internal oscillator locks to the external source, enabling deterministic EMI placement and multi-phase interleaving in systems with multiple LT3942HUFD#TRPBF devices. This capability is fully specified and tested across temperature and voltage ranges.
LT3942HUFD#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)
LT3942HUFD#TRPBF FAQ
1.How can I place an order for LT3942HUFD#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3942HUFD#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 LT3942HUFD#TRPBF reliable?
The price and inventory of LT3942HUFD#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3942HUFD#TRPBF is usually 5 days.
3.What payment methods are accepted for LT3942HUFD#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3942HUFD#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3942HUFD#TRPBF?
LT3942HUFD#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3942HUFD#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 LT3942HUFD#TRPBF?
For technical support, including LT3942HUFD#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3942HUFD#TRPBF requirements.
6.How does Aetrix verify that LT3942HUFD#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT3942HUFD#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 LT3942HUFD#TRPBF meets industry standards.
7.What is the process for return or replacement of LT3942HUFD#TRPBF?
All LT3942HUFD#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3942HUFD#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 LT3942HUFD#TRPBF part is unused and in its original packaging.
Return procedure for LT3942HUFD#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LT3942HUFD#TRPBF Tags
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BCR402RE6327HTSA1
Infineon Technologies
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BCR430UXTSA2
Infineon Technologies
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BCR420UE6433HTMA1
Infineon Technologies
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BCR420UE6327HTSA1
Infineon Technologies
-
BCR421UE6327HTSA1
Infineon Technologies
-
LYT1604D-TL
Power Integrations
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HV9910CLG-G
Microchip Technology
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CL2N8-G
Microchip Technology
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BCR420UW6-7
Diodes Incorporated
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BCR421UW6-7
Diodes Incorporated
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BCR420UFD-7
Diodes Incorporated
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BCR421UFD-7
Diodes Incorporated
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