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Analog Devices Inc. LT3922HUFD#TRPBF
- Part No.:
- LT3922HUFD#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- LED Drivers
- Package:
- 28-WFQFN Exposed Pad
- Datasheet:
-
LT3922HUFD#TRPBF.pdf
- Description:
- IC LED DRVR CTRLR PWM 2.3A 28QFN
- Quantity:
- Payment:
- Shipping:
Inventory:4,603
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Product details
Overview
LT3922HUFD#TRPBF from Analog Devices is a monolithic, synchronous step-up LED driver IC with ±2.5% LED current regulation, 2.8V–36V input range, and 2A internal switches. It supports PWM and analog dimming, operates in boost/buck-boost modes, and delivers up to 34V LED string voltage for automotive lighting and machine vision systems.
For engineers reviewing the LT3922HUFD#TRPBF datasheet, LT3922HUFD#TRPBF pinout, LT3922HUFD#TRPBF application, or LT3922HUFD#TRPBF equivalent, key selection factors include its 200kHz–2MHz programmable switching frequency, spread-spectrum EMI reduction, open/short LED fault reporting, thermal shutdown at 150°C junction, and integrated PWM driver for external high-side PMOS dimming control.
Technical Context
The LT3922HUFD#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 oscillator supports RT-resistor programming or external SYNC clock injection.
It integrates an internal 2V reference (±0.5% over temperature), 1.2V FB threshold for output overvoltage protection, and dedicated fault logic that pulls FAULT low on open-circuit (FB > 1.14V + low sense) or short-circuit (ISP–ISN > 150mV) conditions - all validated across –40°C to 150°C junction range.
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% - maintained over full output voltage range using external sense resistor feedback. |
| Switching Frequency Range | 200kHz to 2MHz - programmable via RT pin resistor or external SYNC signal for EMI optimization. |
| Internal Switch Ratings | 2A peak, 40V max - enables direct drive of medium-power LED strings without external FETs. |
| Junction Temperature Range | –40°C to 150°C - qualified for under-hood automotive and high-ambient industrial environments. |
| Dimming Capability | 5000:1 PWM dimming at 100Hz - achieved via external PWM signal or internal generator with RP-set frequency. |
| Fault Reporting | Open/short LED detection with open-drain FAULT pin - enables system-level diagnostics and safety response. |
Pinout & Package
LT3922HUFD#TRPBF uses a thermally enhanced 28-lead (4mm × 5mm) plastic QFN package with exposed pad (Pin 29) soldered to PCB ground for thermal management (θJA = 34°C/W).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| SW | Switch Node | Internally connected 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 capacitor to SW for charge pump operation. |
| INTVCC | Internal LDO Output | Supplies gate drivers; bypass with 2.2µF ceramic capacitor to GND near package. |
| EN/UVLO | Enable & Undervoltage Lockout | Enables switching above 1.33V; hysteresis ensures clean startup/shutdown during brownout. |
| CTRL | LED Current Programming | Accepts analog voltage (0.25–1.25V) or digital pulse duty cycle (12.5–62.5%) to set regulated LED current. |
| ISP / ISN | Differential Current Sense Inputs | Kelvin-connected across external sense resistor to enable ±2.5% current regulation accuracy. |
| FB | Voltage Feedback Input | Monitors LED string voltage; triggers overvoltage lockout at 1.266V to protect LEDs. |
| PWMTG | PWM Gate Driver Output | Drives external high-side PMOS for PWM dimming; supports fast turn-on/turn-off (110/140ns propagation). |
| FAULT | Open-Drain Fault Indicator | Pulled low on open-circuit (FB > 1.14V + low ISP–ISN) or short-circuit (ISP–ISN > 150mV) conditions. |
| RT | Frequency Programming | Resistor to GND sets switching frequency; 45.3kΩ yields 2MHz, 499kΩ yields ~200kHz. |
| SYNC/SPRD | External Clock Input / Spread Spectrum Enable | Tied to INTVCC to activate spread-spectrum modulation; driven externally for synchronization. |
| RP | Internal PWM Frequency Set | Resistor to GND programs internal PWM frequency (7.3–129kHz); tie to GND for external PWM control. |
Key Features
| Feature | Design Value |
|---|---|
| Silent Switcher® architecture | Reduces radiated/conducted EMI through optimized internal layout and spread-spectrum frequency modulation. |
| Multi-mode topology support | Operates in boost, buck, and buck-boost configurations - enables flexible LED string voltage management. |
| Integrated PWM driver | Drives external high-side PMOS with 11V gate swing (VOUT – VPWMTG) for robust dimming control. |
| Accurate current monitor | ISMON pin outputs 10mV per 1mV ISP–ISN differential - provides real-time LED current telemetry. |
| Thermal and fault protection | Includes thermal shutdown, open/short LED detection, input OVLO, and FB overvoltage lockout. |
Applications
| Automotive Headlamp Systems | Industrial Machine Vision Lighting |
|---|---|
|
Use Scenario: High-intensity, thermally demanding LED arrays in vehicle headlamps requiring precise current control and fault resilience. IC Role / Device Role / Timing Role: Primary LED current regulator and PWM dimming controller with open/short LED fault reporting for ASIL-B–compatible lighting modules. Use Value: ±2.5% current regulation ensures consistent lumen output across temperature; 150°C junction rating supports under-hood placement without derating. |
Use Scenario: Stroboscopic illumination for high-speed inspection cameras where timing precision and flicker-free dimming are critical. IC Role / Device Role / Timing Role: Synchronous boost converter with 5000:1 PWM dimming and <140ns PWM-to-PWMTG propagation for sub-millisecond exposure control. Use Value: Internal PWM generator (7.3–129kHz) eliminates need for external timing IC; spread-spectrum mode reduces EMI interference with image sensors. |
| Outdoor Signage Power Supplies | Medical Endoscope Illumination |
|
Use Scenario: Outdoor LED signage exposed to wide ambient temperatures and variable input voltages from solar/battery sources. IC Role / Device Role / Timing Role: Wide-input (2.8–36V) boost LED driver with UVLO/OVLO protection and thermal shutdown for unattended operation. Use Value: 200kHz–2MHz frequency programming allows optimization for efficiency vs. size; 34V max VOUT supports multi-LED series strings. |
Use Scenario: Compact, low-noise LED light source inside endoscopes requiring silent operation and minimal electromagnetic interference. IC Role / Device Role / Timing Role: Low-EMI LED driver with Silent Switcher® architecture and internal soft-start to prevent inrush-induced mechanical vibration. Use Value: Spread-spectrum modulation and optimized layout reduce conducted noise below medical EMC limits; ISMON enables closed-loop brightness calibration. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar LED driver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3783EFE#TRPBF | Non-synchronous boost controller; requires external MOSFETs; no integrated PWM driver or ISMON. | Lacks internal PWM dimming and fault reporting; suited for higher-power discrete designs with custom gate drive. | Select when >2A output or discrete FET optimization is required; not drop-in compatible due to different pinout and control scheme. |
| LM3409QMY/NOPB | Asynchronous boost LED driver; 1.25A max; no spread spectrum; lower temp grade (–40°C to 125°C). | No internal PWM generator or Silent Switcher® EMI reduction; limited to lower-current, cost-sensitive applications. | Choose for simpler, lower-cost designs where 5000:1 dimming and automotive-grade thermal performance are not required. |
Compared with LTC3783EFE#TRPBF and LM3409QMY/NOPB, the LT3922HUFD#TRPBF delivers higher integration (dual switches, PWM driver, ISMON), superior thermal capability (150°C), and advanced EMI mitigation - making it optimal for space-constrained, high-reliability LED systems.
Availability
LT3922HUFD#TRPBF is available at Aetrix Electronics and suitable for automotive lighting, machine vision systems, and outdoor signage requiring stable component supply, long-term lifecycle support, and AEC-Q100–aligned reliability.
Supply support for LT3922HUFD#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 industrial, automotive, communications, and healthcare markets.
The LT3922 product line was designed for high-efficiency, high-reliability LED lighting in thermally demanding environments - emphasizing precision current regulation, fault resilience, and EMI-conscious architecture.
FAQ
What is the maximum LED string voltage supported by the LT3922HUFD#TRPBF?
The LT3922HUFD#TRPBF supports up to 34V LED string voltage, verified across its full operating temperature range (–40°C to 150°C). This enables driving medium-length LED strings (e.g., 10–12 white LEDs at 3V each) directly from 12V or 24V rails without intermediate conversion stages. The FB overvoltage threshold (1.266V) ensures automatic shutdown if the string voltage exceeds safe limits.
Does the LT3922HUFD#TRPBF support both analog and PWM dimming simultaneously?
No - the LT3922HUFD#TRPBF supports either analog dimming (via CTRL pin voltage) or PWM dimming (via PWM pin or internal generator), but not simultaneous dual-mode control. When using internal PWM dimming, the RP pin sets frequency and the PWM pin sets duty cycle (1V–2V); for analog control, the CTRL pin is used while RP is grounded. Mixing both invalidates regulation accuracy.
How does the LT3922HUFD#TRPBF handle open-circuit LED faults?
The LT3922HUFD#TRPBF detects open-circuit conditions when FB voltage rises above 1.140V while ISP–ISN falls below 10mV, pulling the open-drain FAULT pin low. This event triggers hiccup-mode restart (if SS pin has no resistor) or latch-off (if 100kΩ resistor connects SS to INTVCC), providing configurable safety response per IEC 62368-1 requirements.
What is the purpose of the SYNC/SPRD pin on the LT3922HUFD#TRPBF?
The SYNC/SPRD pin on the LT3922HUFD#TRPBF serves dual functions: (1) accepting external clock signals (200kHz–2MHz) to synchronize switching frequency across multiple converters, and (2) enabling spread-spectrum frequency modulation (SSFM) when tied to INTVCC - reducing peak EMI by dithering frequency between 100% and 125% of nominal value.
Can the LT3922HUFD#TRPBF operate in buck mode, and what are the requirements?
Yes - the LT3922HUFD#TRPBF supports buck-mode operation when configured with appropriate external components (e.g., input capacitor, inductor, and diode). In buck mode, VIN must exceed VOUT, and the SW node connects to the input rail while VOUT supplies the LED string. The datasheet confirms functional validation in buck, boost, and buck-boost topologies across the full –40°C to 150°C range.
LT3922HUFD#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 ~ 150°C (TJ)
- Grade:
- Automotive
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 28-QFN (4x5)
LT3922HUFD#TRPBF FAQ
1.How can I place an order for LT3922HUFD#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3922HUFD#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 LT3922HUFD#TRPBF reliable?
The price and inventory of LT3922HUFD#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3922HUFD#TRPBF is usually 5 days.
3.What payment methods are accepted for LT3922HUFD#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3922HUFD#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3922HUFD#TRPBF?
LT3922HUFD#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3922HUFD#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 LT3922HUFD#TRPBF?
For technical support, including LT3922HUFD#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3922HUFD#TRPBF requirements.
6.How does Aetrix verify that LT3922HUFD#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT3922HUFD#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 LT3922HUFD#TRPBF meets industry standards.
7.What is the process for return or replacement of LT3922HUFD#TRPBF?
All LT3922HUFD#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3922HUFD#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 LT3922HUFD#TRPBF part is unused and in its original packaging.
Return procedure for LT3922HUFD#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LT3922HUFD#TRPBF Tags
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