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Analog Devices Inc. LT3922HUFD#PBF
- Part No.:
- LT3922HUFD#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- LED Drivers
- Package:
- 28-WFQFN Exposed Pad
- Datasheet:
-
LT3922HUFD#PBF.pdf
- Description:
- IC LED DRVR CTRLR PWM 2.3A 28QFN
- Quantity:
- Payment:
- Shipping:
Inventory:942
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Product details
Overview
LT3922HUFD#PBF from Analog Devices is a monolithic, synchronous step-up LED driver IC with ±2.5% LED current regulation, 2.8V–36V input range, 2A internal switches, programmable 200kHz–2MHz switching frequency, and integrated PWM dimming control for high-brightness LED strings in automotive and industrial lighting systems.
For engineers reviewing the LT3922HUFD#PBF datasheet, LT3922HUFD#PBF pinout, LT3922HUFD#PBF application, or LT3922HUFD#PBF equivalent, key selection considerations include thermal performance at 150°C junction, open/short LED fault reporting via FAULT pin, spread spectrum EMI reduction, and dual analog/digital (duty-cycle) LED current programming at the CTRL pin.
Technical Context
The LT3922HUFD#PBF implements fixed-frequency peak current mode control with internal 2A synchronous power switches (140mΩ bottom, 155mΩ top), supporting boost, buck, and buck-boost topologies. Its current regulation loop uses ISP/ISN differential sensing and a transconductance amplifier (gm = 140µA/V) referenced to a buffered 2V VREF.
It integrates dual dimming paths: external PWM signal at PWM pin drives PWMTG gate output for high-side PMOS switching, while internal PWM generation (7.34–129kHz) is enabled via RP resistor and controlled by analog voltage (1V–2V) on PWM pin. Fault detection includes open-circuit (FB > 1.14V + low ISP–ISN) and short-circuit (ISP–ISN > 150mV) conditions with open-drain FAULT reporting.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 2.8V to 36V - supports wide-input industrial and automotive battery rails without pre-regulation. |
| LED Current Regulation Accuracy | ±2.5% - ensures consistent brightness across temperature and line/load variations. |
| Switching Frequency Range | 200kHz to 2MHz - enables compact magnetics and EMI optimization via RT resistor or SYNC clock. |
| Max Junction Temperature | 150°C - validated for under-hood automotive and high-ambient industrial environments. |
| Internal Switch Ratings | 2A, 40V - eliminates need for external power MOSFETs in ≤10W LED applications. |
| PWM Dimming Ratio | 5000:1 at 100Hz - achieves deep dimming without color shift in machine vision and display backlighting. |
| Fault Reporting | Open-drain FAULT pin - signals LED open/short conditions with latchoff or hiccup recovery modes selectable via SS pin resistor. |
Pinout & Package
LT3922HUFD#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 dissipation (θJA = 34°C/W).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| SW | Switch Node | Internally connects to both power switches; must be tied together and routed with low-inductance layout for stable operation. |
| BST | Bootstrap Supply | Drives top switch gate; requires 33nF ceramic capacitor to SW close to package for reliable high-side conduction. |
| ISP / ISN | Differential Current Sense Inputs | Kelvin-connected across external sense resistor to enable ±2.5% LED current regulation independent of trace resistance. |
| CTRL | LED Current Programming Input | Accepts analog voltage (0.25V–1.25V) or digital pulse (12.5%–62.5% duty) to set regulated LED current with hysteresis-based disable threshold. |
| PWM / RP / PWMTG | Dimming Control Interface | PWM pin accepts analog voltage or external signal; RP sets internal PWM frequency; PWMTG drives external high-side PMOS for true PWM dimming. |
| FAULT | Open-Drain Fault Indicator | Pulled low during open-circuit (VFB > 1.14V + low ISP–ISN) or short-circuit (ISP–ISN > 150mV) conditions for system-level diagnostics. |
Key Features
| Feature | Design Value |
|---|---|
| Silent Switcher® Architecture | Reduces radiated/conducted EMI through optimized internal layout and balanced switching node routing - critical for automotive EMC compliance. |
| Spread Spectrum Frequency Modulation | Modulates switching frequency by ±25% when SYNC/SPRD = 3V - lowers peak EMI amplitude without affecting regulation performance. |
| Integrated 2V Reference (VREF) | Buffered 2V output with 3.2mA drive capability - supplies precise bias for CTRL and PWM resistor networks without external references. |
| LED Current Monitor (ISMON) | Provides 10mV/mV scaled replica of ISP–ISN voltage - enables real-time current telemetry and closed-loop feedback in smart lighting systems. |
| Thermal Grade H | Guaranteed operation from –40°C to 150°C junction - qualified for engine compartment and high-power industrial LED drivers. |
Applications
| Automotive Headlamp Driver | Industrial Machine Vision Illumination |
|---|---|
Use Scenario: High-intensity LED headlamps requiring adaptive beam shaping and thermal derating in under-hood environments. IC Role / Device Role / Timing Role: Synchronous boost LED driver regulating 30V/333mA string with ±2.5% current accuracy and 150°C junction rating. Use Value: Maintains consistent lumen output across ambient temperatures up to 125°C ambient, supported by thermal shutdown and fault reporting. | Use Scenario: Stroboscopic LED arrays for high-speed inspection cameras requiring precise 5000:1 dimming depth at 100Hz. IC Role / Device Role / Timing Role: PWM-dimming controller generating clean, jitter-free gate drive for external PMOS with <140ns propagation delay. Use Value: Eliminates motion blur via synchronized strobe timing while preserving color fidelity through true current-source dimming. |
| UV-C Disinfection Module | Architectural LED Retrofit Driver |
Use Scenario: High-voltage UV-C LED strings (up to 34V) powered from 12V DC bus in portable sterilization devices. IC Role / Device Role / Timing Role: Boost converter with open/short LED protection and FB overvoltage lockout (1.266V threshold) preventing catastrophic failure. Use Value: Ensures safe operation during LED degradation or cold-start surge by disabling output before overvoltage stress occurs. | Use Scenario: Retrofit LED tubes replacing fluorescent fixtures, operating from 24V–36V industrial supply with minimal board space. IC Role / Device Role / Timing Role: Compact 4mm × 5mm QFN LED driver supporting buck-boost topology to maintain regulation as input drops below VOUT. Use Value: Enables single-driver solution across varying input voltages without topology change or external FETs. |
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; 100kHz–1MHz range. | Lacks integrated 2A switches and PWM dimming driver; suited for higher-power designs where discrete FETs are preferred. | Select when >2A output current or custom gate drive timing is required; not drop-in compatible. |
| MAX20050ATPA/VY+ | Automotive-grade 2.2MHz boost LED driver; 3.5A switches; AEC-Q100 Grade 1; no internal PWM generator. | Higher current rating and automotive qualification, but lacks RP-based internal PWM dimming and Silent Switcher EMI reduction. | Prefer for AEC-Q100-compliant headlamp modules needing >2A; requires external PWM source for dimming. |
Compared with LTC3783EFE#PBF and MAX20050ATPA/VY+, the LT3922HUFD#PBF delivers integrated 2A switches, ±2.5% current regulation, and on-chip PWM generation - reducing BOM count and PCB area while maintaining 150°C operation and EMI robustness for space-constrained industrial and automotive LED systems.
Availability
LT3922HUFD#PBF is available at Aetrix Electronics and suitable for automotive headlamps, industrial machine vision systems, UV-C disinfection modules, and architectural LED retrofit drivers requiring stable component supply with extended temperature support.
Supply support for LT3922HUFD#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 precision instrumentation, industrial automation, and automotive safety markets.
The LT3922 product line delivers high-efficiency, thermally robust LED drivers with integrated diagnostics and EMI mitigation - designed specifically for demanding lighting applications where reliability, dimming fidelity, and thermal resilience are critical.
FAQ
What is the maximum operating junction temperature for the LT3922HUFD#PBF?
The LT3922HUFD#PBF is rated for continuous operation up to 150°C junction temperature, verified per Analog Devices' H-grade qualification. This exceeds standard E/I-grade parts (125°C) and enables deployment in under-hood automotive and high-ambient industrial environments. Thermal shutdown activates above this limit to protect device integrity, and θJA = 34°C/W assumes proper PCB copper pour under the exposed pad.
How does the LT3922HUFD#PBF achieve 5000:1 PWM dimming ratio?
The LT3922HUFD#PBF achieves 5000:1 PWM dimming at 100Hz by combining precise analog current regulation (±2.5%) with fast, low-jitter gate drive on the PWMTG pin (<140ns turn-off delay). It supports external PWM signals or generates internal PWM using the RP resistor, enabling deep dimming without LED color shift or flicker - critical for machine vision and medical imaging applications.
Can the LT3922HUFD#PBF operate in buck mode, and what design changes are needed?
Yes, the LT3922HUFD#PBF supports buck, boost, and buck-boost configurations per its block diagram and application notes. In buck mode, the LED string connects between VOUT and GND (not high-side), and the FB network is reconfigured to regulate output voltage instead of current. No internal changes are required - only external component selection (inductor, sense resistor, feedback dividers) differs per topology.
What fault conditions does the FAULT pin report on the LT3922HUFD#PBF?
The FAULT pin on the LT3922HUFD#PBF reports two primary conditions: (1) Open LED, detected when FB voltage exceeds 1.14V while ISP–ISN falls below 10mV; and (2) Shorted LED, triggered when ISP–ISN exceeds 150mV for >300µs or reaches 700mV (typical). The FAULT pin pulls low in either case, and recovery behavior (hiccup vs. latchoff) is selected via SS pin resistor configuration.
Is spread spectrum frequency modulation (SSFM) enabled by default on the LT3922HUFD#PBF?
No, spread spectrum frequency modulation is not enabled by default on the LT3922HUFD#PBF. SSFM activates only when the SYNC/SPRD pin is pulled to INTVCC (typically ~3V). With SYNC/SPRD grounded or floating, the device operates at the frequency set by the RT resistor. When SSFM is active, switching frequency varies ±25% around the RT-set center frequency to reduce EMI peaks.
LT3922HUFD#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 ~ 150°C (TJ)
- Grade:
- Automotive
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 28-QFN (4x5)
LT3922HUFD#PBF FAQ
1.How can I place an order for LT3922HUFD#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3922HUFD#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 LT3922HUFD#PBF reliable?
The price and inventory of LT3922HUFD#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3922HUFD#PBF is usually 5 days.
3.What payment methods are accepted for LT3922HUFD#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3922HUFD#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3922HUFD#PBF?
LT3922HUFD#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3922HUFD#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 LT3922HUFD#PBF?
For technical support, including LT3922HUFD#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3922HUFD#PBF requirements.
6.How does Aetrix verify that LT3922HUFD#PBF is sourced from the original manufacturer or authorized distributors?
All LT3922HUFD#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 LT3922HUFD#PBF meets industry standards.
7.What is the process for return or replacement of LT3922HUFD#PBF?
All LT3922HUFD#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3922HUFD#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 LT3922HUFD#PBF part is unused and in its original packaging.
Return procedure for LT3922HUFD#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LT3922HUFD#PBF Tags
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