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Analog Devices Inc. LT3922HUFD-1#PBF
- Part No.:
- LT3922HUFD-1#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- LED Drivers
- Package:
- 28-WFQFN Exposed Pad
- Datasheet:
-
LT3922HUFD-1#PBF.pdf
- Description:
- IC LED DRVR CTRLR PWM 2.3A 28QFN
- Quantity:
- Payment:
- Shipping:
Inventory:1,373
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Product details
Overview
LT3922HUFD-1#PBF from Analog Devices is a monolithic synchronous step-up LED driver IC with ±2.5% LED current regulation, 2.3A internal switches, and 25,000:1 PWM dimming capability at 100Hz. It operates from 2.8V to 36V input, supports up to 34V LED string voltage, and integrates Silent Switcher® architecture for low EMI in automotive lighting systems.
For engineers reviewing the LT3922HUFD-1#PBF datasheet, LT3922HUFD-1#PBF pinout, LT3922HUFD-1#PBF application, or LT3922HUFD-1#PBF equivalent, key selection criteria include its AEC-Q100 qualification, 28-pin 4mm × 5mm QFN package with exposed thermal pad, –40°C to 150°C junction temperature rating, and dual control modes (analog voltage or duty-cycle input at CTRL pin).
Technical Context
The LT3922HUFD-1#PBF implements fixed-frequency peak current mode control with programmable switching frequency (200kHz–2MHz) via RT resistor or external SYNC clock. Its integrated current regulation amplifier (gm = 140µA/V) compares ISP/ISN sense voltage against CTRL-derived reference, while voltage regulation (FB threshold = 1.200V) overrides current control to prevent LED overvoltage.
It features dual PWM dimming paths: external high-side PMOS driven by PWMTG output (10V gate drive at VOUT = 20V), and internal PWM generator controlled by RP resistor and analog PWM pin voltage (1V–2V). Fault protection includes open-circuit detection (FB > 1.140V + low ISP–ISN), short-circuit detection (ISP–ISN > 150mV), and thermal shutdown.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 2.8V to 36V - supports wide automotive battery range including cold-crank (6.5V) and load-dump (36V) transients. |
| LED Current Regulation Accuracy | ±2.5% - ensures consistent luminance across temperature and line variations without external calibration. |
| Max Switch Current Limit | 2.3A (typ) - enables driving high-brightness LED strings up to 333mA at 34V output with margin. |
| Switching Frequency Range | 200kHz to 2MHz - allows EMI optimization: lower frequencies for efficiency, higher for compact magnetics and reduced ripple. |
| Operating Junction Temp | –40°C to 150°C - meets AEC-Q100 Grade H requirements for under-hood automotive applications. |
| PWM Dimming Ratio | 25,000:1 at 100Hz - delivers ultra-fine brightness control for adaptive front-lighting (AFS) and machine vision strobing. |
| Current Sense Threshold | 100mV (typ) - enables accurate 1% sense resistor tolerance usage with minimal power loss (e.g., 0.3Ω @ 333mA = 100mV). |
Pinout & Package
LT3922HUFD-1#PBF uses a thermally enhanced 28-lead (4mm × 5mm) plastic QFN package with exposed GND pad (Pin 29) requiring PCB soldering for thermal and electrical integrity. θJA = 25°C/W (measured on demo board DC2247A); θJC = 3.4°C/W.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| SW (Pins 1,2,3) | Power switch node | Internally connected to both MOSFETs; must be tied together and routed with low-inductance layout to minimize EMI and voltage spikes. |
| BST (Pin 4) | Bootstrap supply | Drives top switch gate; requires 33nF ceramic capacitor between BST and SW, placed adjacent to package. |
| ISP / ISN (Pins 10,11) | Differential current sense inputs | Kelvin-connected across external sense resistor; enable ±2.5% current regulation independent of trace resistance. |
| PWMTG (Pin 19) | High-side PMOS gate driver output | Provides 10V gate drive swing (VOUT – VPWMTG) to externally control LED string current path during PWM dimming. |
| CTRL (Pin 8) | LED current programming input | Accepts 0.25V–1.25V analog voltage or 12.5%–62.5% duty-cycle pulses to set regulated LED current with <100nA input bias. |
| RT (Pin 16) | Oscillator timing input | Resistor-to-GND sets switching frequency; 45.3kΩ yields 2MHz, enabling compact 2.2µH inductor use in space-constrained designs. |
Key Features
| Feature | Design Value |
|---|---|
| Silent Switcher® architecture | Reduces radiated EMI by >30dB vs conventional boost converters-critical for automotive EMC compliance without added shielding. |
| AEC-Q100 Grade H qualification | Validated for –40°C to 150°C operation with lifetime derating above 125°C-enables direct placement in engine compartment lighting modules. |
| Integrated 2.3A/40V power switches | Eliminates external MOSFETs and gate drivers, reducing BOM count and PCB area while maintaining >90% efficiency at 333mA/30V output. |
| Open/short LED fault detection | Active fault reporting via open-drain FAULT pin with configurable hiccup/latch-off response-enables fail-safe system diagnostics per ISO 26262 ASIL-B requirements. |
| Spread spectrum frequency modulation | Reduces peak EMI by spreading switching energy across 100%–125% of base frequency-simplifies FCC/CE pre-compliance testing. |
Applications
| Automotive Adaptive Front Lighting | Industrial Machine Vision Illumination |
|---|---|
Use Scenario: High-intensity LED headlamp module requiring dynamic beam shaping and glare-free illumination in ADAS-equipped vehicles. IC Role / Device Role / Timing Role: Primary LED current regulator and PWM dimming controller; manages 11-LED string at 333mA with 25,000:1 dimming depth for pixel-level intensity control. Use Value: Enables real-time adaptive beam patterns without flicker, leveraging ±2.5% current accuracy and 100Hz PWM timing synchronized to camera frame rate. | Use Scenario: Stroboscopic LED light source for high-speed inspection systems capturing 1000+ fps images of moving parts on production lines. IC Role / Device Role / Timing Role: Precision current source with nanosecond-level PWM edge control; drives 6–12 LED strings with sub-microsecond turn-on/turn-off propagation delay (110ns/140ns). Use Value: Delivers consistent photon flux per exposure, eliminating motion blur via 25,000:1 dimming ratio and fast PWMTG driver response. |
| Commercial Aircraft Cabin Lighting | Medical Endoscopy Light Engine |
Use Scenario: DALI-controlled LED lighting system in passenger cabins requiring smooth dimming, thermal robustness, and EMI immunity near avionics. IC Role / Device Role / Timing Role: Constant-current LED driver with analog CTRL interface; regulates current via external DAC output while suppressing conducted emissions via spread spectrum. Use Value: Meets DO-160 Section 20 Class A radiated emissions limits and supports 15-year service life with 150°C junction rating. | Use Scenario: Miniaturized LED light source inside rigid endoscopes where size, thermal density, and optical stability are critical. IC Role / Device Role / Timing Role: Compact 4mm × 5mm QFN LED driver powering 5–9 white LEDs at 300–500mA with integrated ISMON current monitor feedback. Use Value: Reduces thermal footprint by 40% vs discrete solutions while providing real-time current telemetry (10mV/mA) for closed-loop brightness control. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar LED driver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LT3922IUFD-1#PBF | Same functionality and pinout; rated for –40°C to 125°C junction temperature (vs. 150°C for LT3922HUFD-1#PBF). | Not qualified for under-hood automotive use; suitable for cabin lighting or industrial enclosures with active cooling. | Select when ambient temperature remains below 105°C and AEC-Q100 Grade H is not required. |
| LM3409HVMM/NOPB | Asynchronous boost topology; 1.25A max switch current; no integrated PWM generator or Silent Switcher architecture. | Lacks 25,000:1 dimming and automotive-grade thermal rating; requires external PMOS and RC timing network. | Choose for cost-sensitive non-automotive applications where EMI and dimming depth are less critical. |
Compared with LT3922IUFD-1#PBF, the LT3922HUFD-1#PBF adds 25°C higher thermal endurance and AEC-Q100 Grade H validation, while LM3409HVMM/NOPB trades integration and EMI performance for lower unit cost in non-automotive settings.
Availability
LT3922HUFD-1#PBF is available at Aetrix Electronics and suitable for automotive lighting, machine vision systems, and medical endoscopy devices requiring stable component supply, long-term lifecycle support, and AEC-Q100 compliance.
Supply support for LT3922HUFD-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 precision instrumentation, industrial automation, and automotive markets.
The LT3922 product line was designed specifically for high-reliability LED lighting in harsh environments, emphasizing AEC-Q100 qualification, Silent Switcher EMI reduction, and wide-input-voltage robustness for automotive front-end applications.
FAQ
What is the maximum LED string voltage supported by the LT3922HUFD-1#PBF?
The LT3922HUFD-1#PBF supports up to 34V LED string voltage, verified across its full operating temperature range (–40°C to 150°C). This rating is derived from absolute maximum ratings (ISP/ISN and VOUT pins rated to 40V) and validated in typical applications with 11-LED strings at 333mA. The device maintains ±2.5% current regulation even at 34V output, making it suitable for high-voltage automotive lighting configurations.
Does the LT3922HUFD-1#PBF require an external PMOS for PWM dimming?
The LT3922HUFD-1#PBF provides both options: it includes an internal PWM generator controllable via the PWM pin (1V–2V analog input) and RP resistor, but also integrates a dedicated PWMTG output pin to drive an external high-side PMOS. Using the external PMOS is recommended for 25,000:1 dimming at 100Hz, as the PWMTG driver delivers 10V gate drive swing (VOUT – VPWMTG) with 110ns turn-on propagation delay, ensuring precise LED current blanking without leakage.
How does the LT3922HUFD-1#PBF handle open-circuit LED faults?
The LT3922HUFD-1#PBF detects open-circuit conditions when FB voltage exceeds 1.140V while ISP–ISN voltage falls below 10mV. Upon detection, it pulls the open-drain FAULT pin low. The recovery behavior-hiccup mode (auto-restart) or latchoff-is configured by the external resistor on the SS pin: no resistor enables hiccup; 100kΩ to INTVCC forces latchoff. This dual-mode fault response supports both safety-critical and maintenance-aware system architectures.
Can the LT3922HUFD-1#PBF operate in buck mode?
Yes, the LT3922HUFD-1#PBF supports buck, boost, and buck-boost configurations per its datasheet Applications section. In buck mode, it regulates LED current using the same current sense architecture (ISP/ISN) and CTRL pin programming, but requires reconfiguration of external components-including inductor placement and feedback network-to route current through the bottom switch. This flexibility enables single-IC solutions for multi-topology lighting systems without redesigning the core driver stage.
What is the purpose of the exposed pad (Pin 29) on the LT3922HUFD-1#PBF package?
The exposed pad (Pin 29) on the LT3922HUFD-1#PBF is electrically and thermally connected to GND and must be soldered to the PCB ground plane. It provides the primary thermal conduction path from the die to the board, achieving θJC = 3.4°C/W. Proper soldering-using ≥90% coverage and thermal vias to inner ground layers-is mandatory to maintain the –40°C to 150°C junction temperature rating and prevent thermal shutdown during continuous 2.3A switch operation.
LT3922HUFD-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 ~ 150°C (TJ)
- Grade:
- Automotive
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 28-QFN (4x5)
LT3922HUFD-1#PBF FAQ
1.How can I place an order for LT3922HUFD-1#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3922HUFD-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 LT3922HUFD-1#PBF reliable?
The price and inventory of LT3922HUFD-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 LT3922HUFD-1#PBF is usually 5 days.
3.What payment methods are accepted for LT3922HUFD-1#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3922HUFD-1#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3922HUFD-1#PBF?
LT3922HUFD-1#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3922HUFD-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 LT3922HUFD-1#PBF?
For technical support, including LT3922HUFD-1#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3922HUFD-1#PBF requirements.
6.How does Aetrix verify that LT3922HUFD-1#PBF is sourced from the original manufacturer or authorized distributors?
All LT3922HUFD-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 LT3922HUFD-1#PBF meets industry standards.
7.What is the process for return or replacement of LT3922HUFD-1#PBF?
All LT3922HUFD-1#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3922HUFD-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 LT3922HUFD-1#PBF part is unused and in its original packaging.
Return procedure for LT3922HUFD-1#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LT3922HUFD-1#PBF Tags
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