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Analog Devices Inc. LT3922EUFD#PBF
- Part No.:
- LT3922EUFD#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- LED Drivers
- Package:
- 28-WFQFN Exposed Pad
- Datasheet:
-
LT3922EUFD#PBF.pdf
- Description:
- IC LED DRVR CTRLR PWM 2.3A 28QFN
- Quantity:
- Payment:
- Shipping:
Inventory:7,491
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Product details
Overview
LT3922EUFD#PBF from Analog Devices is a monolithic synchronous step-up LED driver IC with fixed-frequency peak current control, ±2.5% LED current regulation accuracy, 2.8V–36V input range, 34V max LED string voltage, and integrated 2A/40V internal power switches. It supports analog or duty-cycle-based LED current programming and operates in boost, buck, and buck-boost topologies for automotive lighting and machine vision systems.
For engineers reviewing the LT3922EUFD#PBF datasheet, LT3922EUFD#PBF pinout, LT3922EUFD#PBF application, or LT3922EUFD#PBF equivalent, key selection considerations include PWM dimming resolution (5000:1 at 100Hz), spread spectrum EMI reduction, open/short LED fault reporting, thermal shutdown, and compatibility with external high-side PMOS PWM dimming drivers.
Technical Context
The LT3922EUFD#PBF implements a dual-switch synchronous boost architecture with independent current and voltage regulation loops. Its peak current comparator uses VC-pin feedback stabilized by an external RC network, while the FB pin enables overvoltage protection via a resistor divider from VOUT.
It integrates a 2V reference (VREF) with ±0.5% tolerance, programmable switching frequency (200kHz–2MHz via RT pin), and dual dimming control: external digital PWM pulses on the PWM pin or analog voltage-controlled internal PWM generation (0–100% duty cycle) using RP-resistor-set frequency and PWM-pin voltage.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 2.8V to 36V - supports wide-range industrial and automotive battery inputs without pre-regulation. |
| LED Current Regulation Accuracy | ±2.5% - ensures consistent luminance across temperature and line/load variations. |
| Max LED String Voltage | 34V - enables driving up to ~11 white LEDs (3.0V/V) or 12 red/amber LEDs (2.8V/V) in series. |
| Switching Frequency Range | 200kHz to 2MHz - allows optimization of inductor size (e.g., 4.7µH at 2MHz) and EMI profile. |
| PWM Dimming Ratio | 5000:1 at 100Hz - delivers high-fidelity grayscale control for machine vision and display backlighting. |
| Internal Switch Rating | 2A, 40V - handles peak currents for 10W+ LED loads (e.g., 30V × 333mA) with 93% efficiency. |
| Operating Junction Temp | –40°C to +125°C - qualified for under-hood automotive and industrial ambient environments. |
Pinout & Package
LT3922EUFD#PBF is housed in a thermally enhanced 28-lead (4mm × 5mm) plastic QFN package with exposed pad (Pin 29) soldered to PCB ground for optimal thermal performance (θJA = 34°C/W).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| SW | Switch Node | Internally connects both power switches; must be tied together and routed with low-inductance layout for efficient energy transfer. |
| BST | Bootstrap Supply | Drives top switch gate via 33nF capacitor to SW; critical for sustaining high-side FET conduction during boost operation. |
| ISP / ISN | Differential Current Sense Inputs | Kelvin-connected across external sense resistor; enables ±2.5% LED current regulation independent of VOUT. |
| CTRL | LED Current Programming Input | Accepts analog voltage (0.25–1.25V) or 10–62.5% duty-cycle pulse to set regulated LED current with 50mV/mA scaling. |
| PWM / RP / PWMTG | Dimming Control Interface | PWM pin accepts external signal or sets internal PWM duty; RP sets internal frequency; PWMTG drives external high-side PMOS for true PWM dimming. |
| FAULT | Open/Short LED Fault Indicator | Open-drain output pulled low on open-circuit (VFB > 1.14V & ISP−ISN < 10mV) or short-circuit (ISP−ISN > 150mV). |
Key Features
| Feature | Design Value |
|---|---|
| Silent Switcher® Architecture | Reduces radiated EMI through optimized internal layout and differential switching node routing - meets CISPR 25 Class 5 requirements without shielding. |
| Spread Spectrum Frequency Modulation | Modulates switching frequency by ±25% when SYNC/SPRD = 3V - lowers peak EMI amplitude across 100–200MHz band. |
| Integrated Dual Regulation Loops | Simultaneous current (via ISP/ISN) and voltage (via FB) regulation prevents LED overvoltage damage during open-circuit faults. |
| Thermal Shutdown Protection | Halts switching when junction temperature exceeds 150°C (LT3922H grade) or 125°C (E/I grades) - protects against sustained overload conditions. |
| Accurate 2V Reference (VREF) | Stable ±0.5% buffered output capable of sourcing 3mA - used to bias CTRL, PWM, and RP networks without external references. |
Applications
| Automotive Headlamp Systems | Machine Vision Illumination |
|---|---|
Use Scenario: High-brightness adaptive front lighting with dynamic beam shaping and daylight-synchronized intensity control. IC Role / Device Role / Timing Role: Primary LED current regulator and PWM dimming controller managing multiple LED strings in boost configuration. Use Value: ±2.5% current regulation ensures consistent lumen output across battery voltage swings (9–16V), while 5000:1 dimming enables precise glare-free object detection. | Use Scenario: Stroboscopic illumination synchronized to high-speed camera exposure for defect inspection on production lines. IC Role / Device Role / Timing Role: Synchronous boost converter with external PMOS PWM gating, triggered by camera sync signal via PWM pin. Use Value: 110ns PWM-to-PWMTG propagation delay and 2MHz switching enable sub-millisecond flash timing accuracy and minimal motion blur. |
| Industrial Backlighting | UV-C LED Disinfection Modules |
Use Scenario: Wide-input (12–36V) constant-current supply for edge-lit LCD panels requiring flicker-free dimming. IC Role / Device Role / Timing Role: Buck-boost capable LED driver supporting variable VOUT as panel brightness changes, with analog CTRL dimming. Use Value: 2.8V–36V input range eliminates need for separate DC/DC pre-regulator; internal 2V reference simplifies analog dimming circuitry. | Use Scenario: Precision current source for pulsed UV-C LED arrays (265nm) used in medical-grade surface sterilization. IC Role / Device Role / Timing Role: High-efficiency boost driver with open/short LED fault detection and thermal derating for safe pulsed operation. Use Value: Open-circuit fault reporting prevents uncontrolled voltage rise on failed UV-C strings; 125°C operating range supports enclosed thermal environments. |
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 switches; requires external MOSFETs and diode; 1.5A max output current. | Lacks integrated 2A switches and Silent Switcher EMI reduction; suited for lower-power or cost-sensitive designs where board space is less constrained. | Select when discrete power stage optimization is required or when thermal constraints allow external FET placement. |
| LM3409QMH/NOPB | Asynchronous boost; N-channel MOSFET driver only; no internal switches; 1.25A typical output; no spread spectrum or internal PWM generator. | Requires external Schottky diode and gate driver; lacks analog/digital dual-mode CTRL and integrated fault reporting. | Choose for legacy designs or where AEC-Q100 qualification is mandatory (LM3409Q is automotive-grade). |
Compared with LTC3783EFE#PBF and LM3409QMH/NOPB, the LT3922EUFD#PBF provides higher integration (dual internal switches, VREF, PWM generator), superior EMI performance (Silent Switcher + SSFM), and tighter current regulation (±2.5% vs ±5%), making it optimal for space-constrained, high-reliability LED systems demanding flicker-free dimming and robust fault handling.
Availability
LT3922EUFD#PBF is available at Aetrix Electronics and suitable for automotive headlamps, machine vision systems, industrial backlighting, and UV-C disinfection modules requiring stable component supply, long-term lifecycle support, and AEC-Q100-aligned reliability.
Supply support for LT3922EUFD#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, Inc. is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving precision instrumentation, industrial automation, communications, and automotive markets.
The LT3922EUFD#PBF belongs to Analog Devices' Power by Linear™ LED driver product line, engineered specifically for high-efficiency, low-EMI, and fault-resilient constant-current LED control in demanding automotive and industrial environments.
FAQ
What is the maximum LED string voltage supported by the LT3922EUFD#PBF?
The LT3922EUFD#PBF supports up to 34V LED string voltage, verified in the Absolute Maximum Ratings table and confirmed by typical application circuits delivering 30V at 333mA. This enables driving 10–12 series-connected LEDs depending on forward voltage, and is enforced by internal overvoltage protection on the FB pin (1.266V threshold).
Does the LT3922EUFD#PBF require an external PMOS for PWM dimming?
No - the LT3922EUFD#PBF includes a dedicated PWMTG pin that drives an external high-side PMOS for true PWM dimming, but it also features an internal PWM generator controllable via the PWM and RP pins. When RP is grounded, external PWM signals are accepted; when RP is connected to GND via a resistor (e.g., 28.7kΩ), the IC generates its own PWM waveform with adjustable frequency and duty cycle.
How does the LT3922EUFD#PBF handle open-circuit LED faults?
The LT3922EUFD#PBF detects open-circuit LED faults when FB voltage rises above 1.140V while ISP–ISN falls below 10mV, pulling the FAULT pin low. The response mode (hiccup restart or latch-off) is selected by configuring the SS pin: no resistor enables hiccup mode; a 100kΩ resistor to INTVCC enables latch-off, as specified in the Applications Information section.
Can the LT3922EUFD#PBF operate in buck topology?
Yes - the LT3922EUFD#PBF supports buck, boost, and buck-boost configurations per the Features list and Block Diagram. In buck mode, it regulates LED current using the same ISP/ISN sensing and CTRL programming, with VOUT connected to VIN and the LED string referenced to SW. This is validated in application notes and typical schematics for low-VF LED arrays.
What is the purpose of the SYNC/SPRD pin on the LT3922EUFD#PBF?
The SYNC/SPRD pin serves three functions: (1) overriding the RT-programmed frequency with an external clock (200kHz–2MHz), (2) enabling spread spectrum frequency modulation (SSFM) when tied to INTVCC, reducing EMI peaks, and (3) disabling synchronization when tied to GND. Its rising threshold is 1.4V with 0.2V hysteresis, and it draws <100nA - ensuring minimal system loading.
LT3922EUFD#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#PBF FAQ
1.How can I place an order for LT3922EUFD#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3922EUFD#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#PBF reliable?
The price and inventory of LT3922EUFD#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#PBF is usually 5 days.
3.What payment methods are accepted for LT3922EUFD#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3922EUFD#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3922EUFD#PBF?
LT3922EUFD#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3922EUFD#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#PBF?
For technical support, including LT3922EUFD#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3922EUFD#PBF requirements.
6.How does Aetrix verify that LT3922EUFD#PBF is sourced from the original manufacturer or authorized distributors?
All LT3922EUFD#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#PBF meets industry standards.
7.What is the process for return or replacement of LT3922EUFD#PBF?
All LT3922EUFD#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3922EUFD#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#PBF part is unused and in its original packaging.
Return procedure for LT3922EUFD#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LT3922EUFD#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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