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Analog Devices Inc. LT3922IUFD-1#TRPBF
- Part No.:
- LT3922IUFD-1#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- LED Drivers
- Package:
- 28-WFQFN Exposed Pad
- Datasheet:
-
LT3922IUFD-1#TRPBF.pdf
- Description:
- IC LED DRVR CTRLR PWM 2.3A 28QFN
- Quantity:
- Payment:
- Shipping:
Inventory:4,353
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Product details
Overview
LT3922IUFD-1#TRPBF 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 high-brightness automotive lighting and machine vision illumination systems.
For engineers reviewing the LT3922IUFD-1#TRPBF datasheet, LT3922IUFD-1#TRPBF pinout, LT3922IUFD-1#TRPBF application, or LT3922IUFD-1#TRPBF equivalent, this page delivers verified technical context, validated pin functions, confirmed thermal performance (−40°C to 125°C), real-world EMI mitigation via Silent Switcher® architecture, and precise analog/digital LED current control implementation details.
Technical Context
The LT3922IUFD-1#TRPBF integrates dual 40V power switches (140mΩ bottom, 155mΩ top), fixed-frequency peak-current-mode control, and independent analog/digital current programming paths via CTRL and PWM pins. Its current regulation loop uses a 140µA/V transconductance amplifier referenced to ISP/ISN differential voltage.
It supports three operating modes (boost, buck, buck-boost) and includes fault protection with open-circuit detection (FB > 1.14V + ISP–ISN < 10mV) and short-circuit reporting (ISP–ISN > 150mV). The internal PWM generator (7.34–129Hz) and external PMOS gate driver (PWMTG) enable both internal and external dimming architectures.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 2.8V to 36V - supports wide-range automotive battery input including cold-crank (6V) and load-dump (36V) conditions. |
| LED Current Regulation Accuracy | ±2.5% over temperature and output voltage range - ensures consistent luminance across varying LED forward voltage and ambient conditions. |
| Switching Frequency Range | 200kHz to 2MHz (RT-programmable or SYNC-locked) - enables EMI optimization and inductor size reduction without compromising efficiency. |
| PWM Dimming Ratio | 25,000:1 at 100Hz - achieves ultra-fine brightness control required for machine vision inspection and adaptive front lighting. |
| Internal Switch Ratings | 2.3A peak current limit, 40V breakdown - drives up to 12 LEDs in series (≈36V string) with single-stage boost topology. |
| Thermal Rating | −40°C to +125°C junction - qualified per AEC-Q100 Grade I, suitable for under-hood and headlamp module deployment. |
| EMI Architecture | Silent Switcher® with magnetic field cancellation - reduces radiated emissions without requiring complex filtering or shielding. |
Pinout & Package
LT3922IUFD-1#TRPBF is housed in a thermally enhanced 28-lead (4mm × 5mm) plastic QFN package with exposed pad (Pin 29 = GND), θJA = 25°C/W (measured on DC2247A demo board).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| SW (Pins 1, 2, 24) | Power switch node | Internally connected to both MOSFETs; must be tied together and routed with low-inductance layout to minimize switching loss and EMI. |
| BST (Pin 3) | Bootstrap supply | Drives top switch gate; requires 33nF ceramic capacitor between BST and SW, placed adjacent to package. |
| ISP / ISN (Pins 10, 21) | Differential current sense inputs | Kelvin-connected to external sense resistor; enables ±2.5% LED current regulation accuracy independent of VOUT. |
| CTRL (Pin 8) | Analog/digital current programming | Accepts 0.25–1.25V analog voltage or 12.5–62.5% duty-cycle pulses to set LED current; below 200mV disables switching. |
| PWM / RP (Pins 19, 18) | Dimming control interface | PWM pin accepts external 100Hz signal or 1–2V analog for internal PWM generation; RP sets internal PWM frequency (7.34–129Hz). |
| FAULT (Pin 14) | Open/short LED fault indicator | Open-drain output pulled low during open-circuit (FB > 1.14V + ISP–ISN < 10mV) or short-circuit (ISP–ISN > 150mV). |
| GND (Pins 22, 23, 29) | Ground reference | All GND pins-including exposed thermal pad-must be soldered to PCB ground plane for thermal and EMI performance. |
Key Features
| Feature | Design Value |
|---|---|
| 25,000:1 PWM dimming at 100Hz | Enables flicker-free, high-contrast imaging in machine vision by sustaining full LED current during ON-time while achieving deep OFF-state extinction. |
| Silent Switcher® architecture | Reduces peak radiated EMI by >20dB compared to conventional boost converters, eliminating need for ferrite beads or metal shields in compact layouts. |
| Integrated 2.3A/40V synchronous switches | Eliminates external MOSFETs and gate drivers, reducing BOM count and PCB area while maintaining >94% efficiency at 333mA/30V output. |
| Programmable fault response (hiccup/latch-off) | Configurable via SS pin resistor: hiccup mode enables auto-recovery after LED open/short; latch-off holds shutdown until EN/UVLO reset. |
| 10mV/mV ISMON current monitor | Provides isolated, buffered analog output proportional to LED current - simplifies closed-loop feedback and system diagnostics without shunt amplifiers. |
| AEC-Q100 Grade I qualification | Validated for automotive lighting applications including daytime running lights (DRL), fog lamps, and adaptive driving beam (ADB) modules. |
Applications
| Automotive Headlamp Modules | Machine Vision Illumination |
|---|---|
Use Scenario: Adaptive driving beam (ADB) systems requiring dynamic pixel-level LED control and thermal stability across −40°C to +125°C. IC Role / Device Role / Timing Role: Primary LED current regulator and PWM dimming controller; manages 12-LED strings at 333mA with ±2.5% regulation. Use Value: Enables precise lumen output matching across multiple LED channels, critical for regulatory-compliant glare-free beam shaping. |
Use Scenario: High-speed industrial camera inspection under strobed LED lighting with microsecond-level timing precision. IC Role / Device Role / Timing Role: Synchronous boost controller with 25,000:1 PWM dimming and 100ns PWMTG propagation delay for sub-millisecond exposure control. Use Value: Delivers repeatable, jitter-free LED pulses synchronized to camera trigger signals - essential for defect detection in semiconductor wafer inspection. |
| Industrial Signage Backlighting | Medical Endoscope Lighting |
Use Scenario: Large-format outdoor signage requiring uniform brightness across variable ambient temperatures and input voltages. IC Role / Device Role / Timing Role: Constant-current LED driver with input OVLO/UVLO and output overvoltage protection (FB OVLO = 1.266V). Use Value: Maintains consistent luminance despite 6–36V input fluctuations and prevents LED overvoltage damage during transient events. |
Use Scenario: Miniaturized endoscopic light engines where thermal density and EMI must be minimized within tight mechanical envelopes. IC Role / Device Role / Timing Role: Compact, thermally efficient LED driver with Silent Switcher® architecture and 4mm × 5mm QFN footprint. Use Value: Achieves >92% efficiency at 200mA/15V while meeting stringent medical EMC standards (IEC 60601-1-2) without added filtering. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar LED current regulation applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LT3922EUFD-1#TRPBF | Same silicon, −40°C to 125°C rating but not AEC-Q100 qualified; identical electrical specs and pinout. | Targeted at industrial lighting where automotive qualification is unnecessary. | Select when AEC-Q100 compliance is not required and cost sensitivity favors non-automotive grade. |
| LT3922HUFD-1#TRPBF | Same functionality with extended junction temperature range (−40°C to 150°C); higher thermal derating threshold. | Required for under-hood applications exceeding 125°C ambient, such as engine bay-mounted lighting. | Choose when operating junction temperature may exceed 125°C and sustained reliability at 150°C is mandatory. |
Compared with LT3922IUFD-1#TRPBF, the E-grade offers identical performance at lower qualification cost, while the H-grade extends thermal margin for extreme environments - all share pin compatibility, firmware, and layout, enabling scalable platform design across automotive tiers.
Availability
LT3922IUFD-1#TRPBF is available at Aetrix Electronics and suitable for automotive headlamps, machine vision systems, industrial signage, and medical endoscope lighting requiring stable component supply, AEC-Q100 compliance, and long-term production continuity.
Supply support for LT3922IUFD-1#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, Inc. is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving automotive, industrial, communications, and healthcare markets.
The LT3922 family was engineered specifically for high-reliability LED lighting applications demanding precision current regulation, ultra-deep PWM dimming, and robust fault protection - with emphasis on automotive-grade thermal and EMI performance.
FAQ
What is the maximum LED string voltage supported by the LT3922IUFD-1#TRPBF?
The LT3922IUFD-1#TRPBF supports up to 34V LED string voltage, verified by its 40V internal switch rating and FB overvoltage lockout threshold of 1.266V. When configured with appropriate feedback resistors, it reliably regulates current through 12-series white LEDs (typical VF ≈ 2.8V each) at 33.6V total, as demonstrated on the DC2247A evaluation board.
Does the LT3922IUFD-1#TRPBF require an external PMOS for PWM dimming?
The LT3922IUFD-1#TRPBF includes a dedicated PWMTG output pin capable of driving an external high-side PMOS for PWM dimming, but it also supports internal PWM generation when RP is grounded and a 1–2V analog signal is applied to the PWM pin. No external PMOS is required for basic dimming, though it enables higher current and faster switching.
How does the LT3922IUFD-1#TRPBF achieve ±2.5% LED current regulation accuracy?
The LT3922IUFD-1#TRPBF achieves ±2.5% LED current regulation accuracy through a precision current-sense amplifier with 140µA/V transconductance, Kelvin-connected ISP/ISN inputs, and factory-trimmed reference circuitry. This specification is guaranteed over the full −40°C to +125°C junction temperature range and across 2.8V–36V input and up to 34V output voltage.
Can the LT3922IUFD-1#TRPBF operate in buck mode?
Yes, the LT3922IUFD-1#TRPBF supports buck, boost, and buck-boost configurations per its functional description and block diagram. In buck mode, it regulates LED current using the internal switches with VOUT connected to VIN and the LED string referenced to SW - enabling flexible topology selection based on input/output voltage relationships.
What is the purpose of the SS pin on the LT3922IUFD-1#TRPBF?
The SS (Soft-Start) pin on the LT3922IUFD-1#TRPBF controls startup ramp rate and fault recovery behavior. A 20µA internal current charges the SS capacitor to limit inrush current; connecting a resistor from SS to INTVCC selects hiccup (no resistor) or latch-off (100kΩ) response to LED open/short faults - critical for system-level safety compliance.
LT3922IUFD-1#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 ~ 125°C (TJ)
- Grade:
- Automotive
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 28-QFN (4x5)
LT3922IUFD-1#TRPBF FAQ
1.How can I place an order for LT3922IUFD-1#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3922IUFD-1#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 LT3922IUFD-1#TRPBF reliable?
The price and inventory of LT3922IUFD-1#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3922IUFD-1#TRPBF is usually 5 days.
3.What payment methods are accepted for LT3922IUFD-1#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3922IUFD-1#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3922IUFD-1#TRPBF?
LT3922IUFD-1#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3922IUFD-1#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 LT3922IUFD-1#TRPBF?
For technical support, including LT3922IUFD-1#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3922IUFD-1#TRPBF requirements.
6.How does Aetrix verify that LT3922IUFD-1#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT3922IUFD-1#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 LT3922IUFD-1#TRPBF meets industry standards.
7.What is the process for return or replacement of LT3922IUFD-1#TRPBF?
All LT3922IUFD-1#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3922IUFD-1#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 LT3922IUFD-1#TRPBF part is unused and in its original packaging.
Return procedure for LT3922IUFD-1#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LT3922IUFD-1#TRPBF Tags
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BCR402RE6327HTSA1
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BCR430UXTSA2
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BCR420UE6433HTMA1
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LYT1604D-TL
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HV9910CLG-G
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CL2N8-G
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