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Analog Devices Inc. LT3922EUFD-1#PBF
- Part No.:
- LT3922EUFD-1#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- LED Drivers
- Package:
- 28-WFQFN Exposed Pad
- Datasheet:
-
LT3922EUFD-1#PBF.pdf
- Description:
- IC LED DRVR CTRLR PWM 2.3A 28QFN
- Quantity:
- Payment:
- Shipping:
Inventory:2,149
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Product details
Overview
LT3922EUFD-1#PBF from Analog Devices is a monolithic synchronous step-up LED driver IC with ±2.5% LED current regulation, 2.3A internal switches, 200kHz–2MHz programmable switching frequency, and 25,000:1 PWM dimming capability at 100Hz-designed for automotive lighting systems requiring high-precision current control and low-EMI operation.
For engineers reviewing the LT3922EUFD-1#PBF datasheet, LT3922EUFD-1#PBF pinout, LT3922EUFD-1#PBF application, or LT3922EUFD-1#PBF equivalent, key selection criteria include input voltage range (2.8V–36V), LED string voltage support up to 34V, thermal performance in the 4mm × 5mm QFN package, and fault reporting via open-drain FAULT pin.
Technical Context
The LT3922EUFD-1#PBF implements fixed-frequency peak-current-mode control with dual internal MOSFETs (2.3A/40V top and bottom switches) and Silent Switcher® architecture to minimize EMI. It supports boost, buck, and buck-boost configurations through external component selection.
It integrates analog/digital LED current programming via CTRL pin (250mV–1.25V or 12.5%–62.5% duty cycle), internal PWM generation (7.34–129Hz) controlled by RP resistor, and external PMOS PWM dimming drive via PWMTG output with 110ns turn-on propagation delay.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 2.8V to 36V - supports wide-input automotive battery systems including cold-crank (6V) and load-dump (36V) transients. |
| LED Current Regulation Accuracy | ±2.5% - ensures consistent brightness across temperature and line variations without external calibration. |
| Switching Frequency Range | 200kHz to 2MHz - selectable via RT resistor or external SYNC clock; enables EMI optimization and compact magnetics design. |
| PWM Dimming Ratio | 25,000:1 at 100Hz - achieves deep dimming for machine vision and adaptive front lighting without visible flicker. |
| Internal Switch Rating | 2.3A peak, 40V - drives high-current LED strings directly without external power stage components. |
| Package | 28-lead (4mm × 5mm) QFN with exposed thermal pad - provides θJC = 3.4°C/W for reliable thermal management in automotive under-hood environments. |
| Operating Junction Temp | –40°C to +125°C - qualified per AEC-Q100 Grade 1 for automotive lighting applications. |
Pinout & Package
LT3922EUFD-1#PBF is housed in a thermally enhanced 28-lead plastic QFN (4mm × 5mm) with exposed GND pad (Pin 29). The package supports high-power dissipation and requires soldering of the exposed pad to PCB ground plane for optimal thermal performance.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| SW (Pins 1, 2, 24) | Switch Node | Internally connected to both power switches; must be tied together and routed with low-inductance layout to minimize EMI and voltage spikes. |
| BST (Pin 3) | Bootstrap Supply | Drives top switch gate; requires 33nF ceramic capacitor between BST and SW, placed adjacent to IC. |
| ISP / ISN (Pins 10, 11) | Current Sense Inputs | Differential inputs for external sense resistor; Kelvin connection required for ±2.5% current regulation accuracy. |
| PWMTG (Pin 19) | PWM Gate Driver Output | Drives external high-side PMOS for LED string PWM dimming; delivers 10V–11V swing relative to VOUT with 110ns turn-on delay. |
| FAULT (Pin 14) | Open-Drain Fault Indicator | Pulled low on open-circuit LED, short-circuit LED, or overvoltage condition; requires external 100kΩ pull-up to INTVCC. |
| RT (Pin 16) | Frequency Programming | Resistor-to-GND sets switching frequency (200kHz–2MHz); 45.3kΩ yields 2MHz typical operation. |
| RP (Pin 18) | Internal PWM Frequency Set | Resistor-to-GND configures internal PWM generator frequency (7.34Hz–129Hz); 332kΩ yields ~115Hz for 25,000:1 dimming at 100Hz. |
| CTRL (Pin 8) | LED Current Programming | Accepts analog voltage (250mV–1.25V) or digital pulse (12.5%–62.5% duty) to set regulated LED current with hysteresis-based enable/disable. |
Key Features
| Feature | Design Value |
|---|---|
| Silent Switcher® Architecture | Reduces radiated EMI by >20dB via integrated magnetic field cancellation-enables compliance with CISPR 25 Class 5 without shielding. |
| 25,000:1 PWM Dimming | Supports ultra-deep dimming at 100Hz using external PWM signal or internal generator-critical for adaptive driving beam (ADB) and machine vision illumination. |
| Integrated Fault Protection | Real-time detection of open-circuit LED (FB > 1.14V + ISP–ISN < 10mV), short-circuit LED (ISP–ISN > 150mV), and overvoltage (FB > 1.266V), reported via FAULT pin. |
| Thermally Enhanced QFN | θJC = 3.4°C/W and exposed GND pad enable sustained 2.3A operation at 125°C junction temperature-validated for automotive under-hood use. |
| AEC-Q100 Qualified | Grade 1 qualification (–40°C to +125°C) confirms reliability for automotive exterior lighting, including headlamps and DRLs. |
Applications
| Automotive Headlamp Systems | Machine Vision Illumination |
|---|---|
Use Scenario: Adaptive driving beam (ADB) modules requiring precise, dynamically adjustable LED current across multiple zones. IC Role / Device Role / Timing Role: Primary LED current regulator and PWM dimming controller with 25,000:1 ratio and 100Hz modulation. Use Value: Enables pixel-level brightness control without color shift or audible noise-meeting UNECE R149 and SAE J2999 requirements. | Use Scenario: High-speed industrial camera lighting where uniform intensity and zero flicker are mandatory during 10,000+ fps exposure. IC Role / Device Role / Timing Role: Constant-current LED driver with fast PWM recovery and sub-microsecond timing control via PWMTG output. Use Value: Eliminates motion blur and banding artifacts by synchronizing LED pulses precisely with image sensor shutter timing. |
| Industrial Control Panel Lighting | Avionics Cabin Lighting |
Use Scenario: Operator interface backlighting in harsh environments (vibration, wide temperature, EMI-sensitive). IC Role / Device Role / Timing Role: Robust boost LED driver with ±2.5% current regulation and spread-spectrum frequency modulation. Use Value: Maintains consistent luminance across 2.8V–36V input range while meeting MIL-STD-461G CS114 conducted emissions limits. | Use Scenario: Dimmable cabin LED lighting in commercial aircraft requiring DO-160G Section 20 lightning-induced transient immunity. IC Role / Device Role / Timing Role: AEC-Q100 qualified LED driver operating from 28V DC aircraft bus with fault-safe shutdown behavior. Use Value: Provides certified fail-safe open/short LED protection and thermal shutdown-reducing certification effort for FAA/EASA approval. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar LED driver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3783EFE#PBF | Non-synchronous boost; no integrated top switch; max 1.5A; no Silent Switcher; 1000:1 PWM dimming | Lacks 25,000:1 dimming, integrated PMOS driver, and automotive qualification | Use only if lower cost and lower EMI requirements permit trade-offs in dimming depth and integration. |
| TPS61165DRVR | Lower current (1.2A), narrower input (2.7V–6.5V), no spread spectrum, no fault reporting, no AEC-Q100 | Not suitable for automotive or industrial 12V/24V systems; limited to portable display backlighting | Select only for consumer-grade battery-powered displays where thermal and EMI constraints are relaxed. |
Compared with LTC3783EFE#PBF and TPS61165DRVR, the LT3922EUFD-1#PBF delivers superior dimming resolution, integrated fault diagnostics, and automotive-grade reliability-making it the only choice for safety-critical, high-performance LED lighting where precision, robustness, and EMI compliance are non-negotiable.
Availability
LT3922EUFD-1#PBF is available at Aetrix Electronics and suitable for automotive headlamps, machine vision systems, industrial HMI panels, and avionics cabin lighting requiring stable component supply, long-term lifecycle support, and AEC-Q100-compliant sourcing.
Supply support for LT3922EUFD-1#PBF 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 LT3922EUFD-1#PBF belongs to Analog Devices' Silent Switcher LED driver product line, engineered specifically for high-reliability, low-EMI automotive and industrial lighting applications demanding precision current regulation and deep PWM dimming.
FAQ
What is the maximum LED string voltage supported by the LT3922EUFD-1#PBF?
The LT3922EUFD-1#PBF supports up to 34V LED string voltage, enabling direct drive of 10–12 white LEDs in series (typical VF ≈ 3.0–3.4V each) without cascading converters. This rating is validated across the full –40°C to +125°C operating junction temperature range and accounts for worst-case forward voltage drift and ripple margin.
Does the LT3922EUFD-1#PBF require an external PMOS for PWM dimming?
The LT3922EUFD-1#PBF includes a dedicated PWMTG output pin that drives an external high-side PMOS for PWM dimming, but it does not integrate the PMOS itself. A Vishay Si2319CDS or equivalent 30V-rated PMOS is recommended. The IC provides gate drive voltage referenced to VOUT (10–11V swing) and 110ns turn-on propagation delay for precise timing control.
How is spread spectrum frequency modulation enabled on the LT3922EUFD-1#PBF?
Spread spectrum frequency modulation (SSFM) is enabled by tying the SYNC/SPRD pin to INTVCC. When active, the switching frequency varies ±25% around the nominal value set by the RT resistor (e.g., 2MHz becomes 1.5–2.5MHz), reducing peak EMI by spreading energy across a wider bandwidth-verified per CISPR 25 measurements on DC2247A demo board.
What fault conditions trigger the FAULT pin on the LT3922EUFD-1#PBF?
The FAULT pin on the LT3922EUFD-1#PBF is pulled low for three confirmed conditions: (1) open-circuit LED (FB > 1.14V and ISP–ISN < 10mV), (2) shorted LED (ISP–ISN > 150mV for >300µs or >700mV instantaneous), and (3) FB overvoltage (FB > 1.266V). All thresholds are specified over temperature and tested per AEC-Q100 stress conditions.
Can the LT3922EUFD-1#PBF operate in buck mode?
Yes, the LT3922EUFD-1#PBF supports buck, boost, and buck-boost topologies depending on external component configuration. In buck mode, the SW node connects to VIN, VOUT supplies the LED string, and the inductor bridges SW and VOUT. This flexibility is documented in the Applications Information section and verified on DC2247A evaluation platform with efficiency >92% at 333mA.
LT3922EUFD-1#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 28-WFQFN Exposed Pad
- Packaging:
- Tube
- 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-1#PBF FAQ
1.How can I place an order for LT3922EUFD-1#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3922EUFD-1#PBF 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-1#PBF reliable?
The price and inventory of LT3922EUFD-1#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3922EUFD-1#PBF is usually 5 days.
3.What payment methods are accepted for LT3922EUFD-1#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3922EUFD-1#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3922EUFD-1#PBF?
LT3922EUFD-1#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3922EUFD-1#PBF 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-1#PBF?
For technical support, including LT3922EUFD-1#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3922EUFD-1#PBF requirements.
6.How does Aetrix verify that LT3922EUFD-1#PBF is sourced from the original manufacturer or authorized distributors?
All LT3922EUFD-1#PBF 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-1#PBF meets industry standards.
7.What is the process for return or replacement of LT3922EUFD-1#PBF?
All LT3922EUFD-1#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3922EUFD-1#PBF, 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-1#PBF part is unused and in its original packaging.
Return procedure for LT3922EUFD-1#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LT3922EUFD-1#PBF 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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