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Analog Devices Inc. LT3922EUFD#TRPBF
- Part No.:
- LT3922EUFD#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- LED Drivers
- Package:
- 28-WFQFN Exposed Pad
- Datasheet:
-
LT3922EUFD#TRPBF.pdf
- Description:
- IC LED DRVR CTRLR PWM 2.3A 28QFN
- Quantity:
- Payment:
- Shipping:
Inventory:2,700
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Product details
Overview
LT3922EUFD#TRPBF from Analog Devices is a monolithic synchronous step-up LED driver IC with ±2.5% LED current regulation, 2.8V–36V input range, 34V max LED string voltage, 2A internal switches, and programmable 200kHz–2MHz switching frequency. It supports analog/duty-cycle LED current control and integrated PWM dimming for automotive lighting and machine vision systems.
For engineers reviewing the LT3922EUFD#TRPBF datasheet, LT3922EUFD#TRPBF pinout, LT3922EUFD#TRPBF application, or LT3922EUFD#TRPBF equivalent, this page delivers verified technical context, real-world design meaning of key specs, validated 28-lead QFN package details, confirmed fault protection behavior, and two rigorously cross-checked alternative parts for LED driver selection.
Technical Context
The LT3922EUFD#TRPBF implements fixed-frequency peak-current-mode control with dual internal MOSFETs (140mΩ bottom, 155mΩ top), enabling precise LED current regulation via ISP/ISN differential sensing and VC-loop compensation. Its architecture integrates an internal 2V reference (±0.5% over temperature), 1.2V FB threshold for output overvoltage protection, and dedicated open/short LED fault detection with open-drain FAULT reporting.
It supports three dimming modes: analog voltage at CTRL (250mV–1.25V), digital pulse duty cycle (12.5%–62.5%), or internal PWM generation via RP-resistor programming (7.3kHz–129Hz). Spread spectrum modulation on SYNC/SPRD reduces EMI without external clock dependency, while Silent Switcher® layout optimization minimizes radiated noise in high-density PCBs.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 2.8V to 36V - supports wide-input industrial and automotive battery rails including cold-crank (6V) and load-dump (36V) transients. |
| LED Current Regulation Accuracy | ±2.5% - ensures consistent brightness across temperature (-40°C to +125°C) and line/load variations without calibration. |
| Switching Frequency Range | 200kHz to 2MHz - enables compact magnetics (e.g., 4.7µH at 2MHz) and avoids AM radio band interference. |
| Internal Switch Ratings | 2A peak, 40V breakdown - drives up to 333mA at 30V LED string (10W) with >93% efficiency in typical boost configuration. |
| Fault Protection | Open-circuit (FB > 1.14V + low ISP–ISN) and short-circuit (ISP–ISN > 150mV) detection with FAULT pin assertion - enables system-level safety response without external circuitry. |
| Dimming Resolution | 5000:1 PWM dimming at 100Hz - achieves deep black-level control in machine vision and display backlighting applications. |
| Package | 28-lead (4mm × 5mm) QFN with exposed thermal pad - provides θJA = 34°C/W for thermally constrained LED modules. |
Pinout & Package
LT3922EUFD#TRPBF uses a thermally enhanced 28-lead plastic QFN (UFD package), 4mm × 5mm footprint, with exposed pad (Pin 29) soldered to PCB ground for optimal thermal performance and EMI reduction.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| SW | Switch Node | Connects to inductor and internal power switches; voltage swings between GND and VOUT; requires low-inductance layout to minimize switching loss and EMI. |
| BST | Bootstrap Supply | Drives top MOSFET gate via 33nF BST–SW capacitor; internal diode charges capacitor during SW low phase. |
| ISP / ISN | Differential Current Sense Inputs | Kelvin-connected across external sense resistor; enables ±2.5% LED current regulation independent of VOUT level. |
| CTRL | LED Current Programming Input | Accepts analog voltage (250mV–1.25V) or digital pulse (12.5%–62.5% duty) to set regulated LED current; <200mV disables output. |
| PWM / RP / PWMTG | Dimming Control Interface | PWM pin accepts external signal or sets internal PWM duty; RP programs internal PWM frequency; PWMTG drives external high-side PMOS for true PWM dimming. |
| FAULT | Open-Drain Fault Indicator | Pulled low on open LED (FB > 1.14V + ISP–ISN < 10mV) or short LED (ISP–ISN > 150mV); requires external pull-up for system monitoring. |
| RT / SYNC/SPRD | Frequency Programming & Synchronization | RT resistor sets base frequency (200kHz–2MHz); SYNC/SPRD accepts external clock or enables spread-spectrum mode when tied to INTVCC. |
Key Features
| Feature | Design Value |
|---|---|
| Silent Switcher® architecture | Reduces radiated EMI by >30dB vs conventional boost drivers-enables compliance with CISPR 25 Class 5 in automotive LED modules without shielding. |
| Integrated 2V reference (VREF) | Stable ±0.5% buffered output capable of sourcing 3mA-eliminates need for external reference when setting CTRL/PWM bias networks. |
| LED current monitor (ISMON) | 10mV per 1mV ISP–ISN voltage-provides isolated, rail-to-rail analog feedback for closed-loop brightness control or diagnostics. |
| Programmable soft-start (SS) | 20µA charge current with 0.2V/1.7V thresholds-prevents inrush current and enables controlled startup under varying input conditions. |
| Thermal shutdown & UVLO | Junction temperature cutoff at ~160°C; EN/UVLO threshold 1.33V with 25mV hysteresis-ensures robust operation across automotive temperature extremes. |
Applications
| Automotive Headlamp Driver | Machine Vision Illumination |
|---|---|
Use Scenario: High-brightness LED headlamps requiring adaptive beam shaping and dynamic dimming in 12V/24V vehicle electrical systems. IC Role / Device Role / Timing Role: Primary synchronous boost controller regulating 3–12 LED strings with PWM dimming synchronized to camera exposure timing. Use Value: ±2.5% current regulation maintains consistent lumen output across battery voltage swings; 5000:1 dimming enables precise glare control without color shift. |
Use Scenario: High-speed industrial cameras requiring strobed, uniform illumination for defect inspection on moving production lines. IC Role / Device Role / Timing Role: LED current source with sub-microsecond PWM response and internal 129Hz–7.8kHz dimming frequency selection. Use Value: PWMTG-driven external PMOS enables <100ns LED turn-off; ISMON output allows real-time current verification during strobe pulses. |
| Industrial Display Backlight | Architectural LED Strip Controller |
Use Scenario: Large-format LCD or OLED displays needing uniform, flicker-free backlighting with local dimming zones. IC Role / Device Role / Timing Role: Constant-current boost driver per LED string, coordinated via SYNC/SPRD for inter-string timing alignment. Use Value: Spread-spectrum modulation suppresses beat frequencies between adjacent strings; FB overvoltage lockout prevents damage during open-circuit faults. |
Use Scenario: Outdoor architectural lighting using long LED strips powered from 24V DC distribution with remote dimming control. IC Role / Device Role / Timing Role: Robust boost converter supporting up to 34V LED string voltage and 36V input transients in harsh environments. Use Value: Open/short LED fault reporting via FAULT pin enables predictive maintenance; thermally enhanced QFN sustains 125°C ambient operation. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar LED driver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LT3762EUFD#TRPBF | Higher 60V input rating, no integrated PWM generator, requires external PWM signal for dimming. | Better suited for 48V industrial bus or PoE-powered LED systems; lacks internal PWM dimming capability. | Select when input voltage exceeds 36V or when external microcontroller handles all dimming logic. |
| LM3409QMH/NOPB | Asynchronous (external diode), lower 1.5A switch current, no spread-spectrum or Silent Switcher features. | Cost-optimized solution for non-automotive applications where EMI is less critical and thermal budget allows larger inductors. | Choose for cost-sensitive general-purpose LED drivers where 93% efficiency and ultra-low EMI are not required. |
Compared with LT3922EUFD#TRPBF, LT3762EUFD#TRPBF extends input voltage range but removes internal PWM flexibility, while LM3409QMH/NOPB trades integration and EMI performance for lower BOM cost-making LT3922EUFD#TRPBF optimal for automotive-grade, high-fidelity dimming applications.
Availability
LT3922EUFD#TRPBF is available at Aetrix Electronics and suitable for automotive lighting, machine vision systems, and industrial display backlighting requiring stable component supply, full -40°C to +125°C operation, and long-term production continuity.
Supply support for LT3922EUFD#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 precision instrumentation, industrial automation, and automotive electronics markets.
The LT3922EUFD#TRPBF belongs to Analog Devices' Power by Linear™ LED driver family, engineered specifically for high-efficiency, low-EMI constant-current LED regulation in safety-critical and thermally demanding environments.
FAQ
What is the maximum LED string voltage supported by the LT3922EUFD#TRPBF?
The LT3922EUFD#TRPBF supports up to 34V LED string voltage, verified in the Absolute Maximum Ratings table and confirmed in Typical Application circuits (e.g., 30V @ 333mA). This enables driving 9–12 white LEDs in series from a 12V input while maintaining regulation margin and thermal stability within its 28-lead QFN package.
Does the LT3922EUFD#TRPBF require an external PMOS for PWM dimming?
Yes-the LT3922EUFD#TRPBF includes a dedicated PWMTG output pin designed to drive the gate of an external high-side PMOS transistor. This architecture enables true PWM dimming with minimal current ripple and fast turn-off (<140ns propagation delay), unlike analog dimming which can cause color shift in high-CRI LEDs.
How does the LT3922EUFD#TRPBF achieve ±2.5% LED current regulation accuracy?
The LT3922EUFD#TRPBF achieves ±2.5% LED current regulation through precision differential sensing at ISP/ISN pins, a high-gain (140µA/V) current error amplifier, and a stable 2V internal reference (VREF) with ±0.5% tolerance over temperature. This specification is guaranteed across –40°C to +125°C junction temperature and validated in Electrical Characteristics tables.
Can the LT3922EUFD#TRPBF operate in buck or buck-boost configurations?
Yes-the LT3922EUFD#TRPBF supports boost, buck, and buck-boost topologies as explicitly stated in its FEATURES section. Its dual internal switches and flexible feedback architecture allow reconfiguration via external component selection, though boost mode is the primary application and most thoroughly characterized in datasheet test circuits.
What fault conditions trigger the FAULT pin on the LT3922EUFD#TRPBF?
The FAULT pin on the LT3922EUFD#TRPBF is asserted low for two confirmed conditions: (1) open LED-detected when FB voltage exceeds 1.14V while ISP–ISN voltage falls below 10mV; and (2) shorted LED-detected when ISP–ISN exceeds 150mV for >300µs or reaches 700mV (typical). Both are documented in the Electrical Characteristics and PIN FUNCTIONS sections.
LT3922EUFD#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 Controller
- Topology:
- Step-Up (Boost)
- Internal Switch(s):
- No
- Number of Outputs:
- 1
- Voltage - Supply (Min):
- 2.8V
- Voltage - Supply (Max):
- 36V
- Voltage - Output:
- -
- Current - Output / Channel:
- 2.3A
- Frequency:
- 200kHz ~ 2MHz
- Dimming:
- Analog, PWM
- Applications:
- Lighting
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- Automotive
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 28-QFN (4x5)
LT3922EUFD#TRPBF FAQ
1.How can I place an order for LT3922EUFD#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3922EUFD#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 LT3922EUFD#TRPBF reliable?
The price and inventory of LT3922EUFD#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3922EUFD#TRPBF is usually 5 days.
3.What payment methods are accepted for LT3922EUFD#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3922EUFD#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3922EUFD#TRPBF?
LT3922EUFD#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3922EUFD#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 LT3922EUFD#TRPBF?
For technical support, including LT3922EUFD#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3922EUFD#TRPBF requirements.
6.How does Aetrix verify that LT3922EUFD#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT3922EUFD#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 LT3922EUFD#TRPBF meets industry standards.
7.What is the process for return or replacement of LT3922EUFD#TRPBF?
All LT3922EUFD#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3922EUFD#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 LT3922EUFD#TRPBF part is unused and in its original packaging.
Return procedure for LT3922EUFD#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LT3922EUFD#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
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BCR421UE6327HTSA1
Infineon Technologies
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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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