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Analog Devices Inc. LT3922IUFD#TRPBF
- Part No.:
- LT3922IUFD#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- LED Drivers
- Package:
- 28-WFQFN Exposed Pad
- Datasheet:
-
LT3922IUFD#TRPBF.pdf
- Description:
- IC LED DRVR CTRLR PWM 2.3A 28QFN
- Quantity:
- Payment:
- Shipping:
Inventory:1,372
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Product details
Overview
LT3922IUFD#TRPBF from Analog Devices is a monolithic, synchronous step-up DC/DC LED driver with ±2.5% LED current regulation, 2.8V–36V input range, and 2A internal switches. It supports analog or duty-cycle-based LED current control via the CTRL pin, delivers up to 34V LED string voltage, and integrates PWM dimming with 5000:1 dimming ratio at 100Hz. It is used in automotive lighting systems requiring high-efficiency, low-EMI boost conversion for multi-LED strings.
For engineers reviewing the LT3922IUFD#TRPBF datasheet, LT3922IUFD#TRPBF pinout, LT3922IUFD#TRPBF application, or LT3922IUFD#TRPBF equivalent, key selection considerations include its 28-pin 4mm × 5mm QFN package, spread-spectrum EMI reduction, open/short LED fault detection, thermal shutdown, and compatibility with external high-side PMOS PWM dimming drivers.
Technical Context
The LT3922IUFD#TRPBF implements fixed-frequency peak-current-mode control with programmable switching frequency (200kHz–2MHz) set by an external RT resistor or synchronized via the SYNC/SPRD pin. Its dual-switch architecture enables boost, buck, and buck-boost topologies, while the integrated current regulation amplifier compares ISP–ISN voltage against a CTRL-derived reference to maintain precise LED current.
It features dual dimming paths: analog control via CTRL pin voltage (250mV–1.25V) or digital pulse-width control via CTRL pin duty cycle (12.5%–62.5%), plus independent PWM dimming using either external pulses on the PWM pin or internally generated PWM (frequency set by RP resistor, 7.3kHz–129Hz). Fault protection includes open-circuit (FB > 1.14V + low ISP–ISN) and short-circuit (ISP–ISN > 150mV) detection with open-drain FAULT reporting.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 2.8V to 36V - supports wide-range industrial and automotive battery inputs including cold-crank and load-dump conditions. |
| LED Current Regulation Accuracy | ±2.5% - ensures consistent brightness across temperature and line variations without external calibration. |
| Switching Frequency Range | 200kHz to 2MHz - allows optimization of efficiency vs. size: higher frequencies reduce inductor/capacitor footprint; lower frequencies improve light-load efficiency. |
| Internal Switch Rating | 2A, 40V - enables direct drive of medium-power LED strings up to ~34V without external MOSFETs. |
| PWM Dimming Ratio | 5000:1 at 100Hz - supports high-fidelity dimming in machine vision and display backlighting where deep contrast is critical. |
| Package & Temp Range | 28-lead 4mm × 5mm QFN, –40°C to +125°C junction - thermally enhanced for compact, high-power-density PCB layouts in harsh environments. |
| EMI Reduction | Silent Switcher® architecture + spread-spectrum modulation - reduces peak radiated emissions by spreading energy across 25% bandwidth, easing EMC compliance. |
Pinout & Package
LT3922IUFD#TRPBF is housed in a thermally enhanced 28-lead plastic QFN (4mm × 5mm), with exposed pad (Pin 29) soldered to PCB ground for optimal thermal performance (θJA = 34°C/W).
| 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 losses and EMI. |
| BST (Pin 3) | Bootstrap supply | Drives top switch gate; requires 33nF ceramic capacitor to SW close to IC for reliable high-side gate drive. |
| ISP / ISN (Pins 10, 11) | Differential current sense inputs | Kelvin-connected to external sense resistor; enable ±2.5% LED current regulation independent of VOUT and temperature. |
| CTRL (Pin 8) | LED current programming | Accepts analog voltage (250mV–1.25V) or PWM duty cycle (12.5%–62.5%) to set regulated LED current; <200mV disables output. |
| PWM / RP / PWMTG (Pins 19, 18, 20) | 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 (Pin 14) | Open-drain fault indicator | Pulled low on open-LED (FB > 1.14V + ISP–ISN < 10mV) or short-LED (ISP–ISN > 150mV); enables system-level fault logging or shutdown. |
Key Features
| Feature | Design Value |
|---|---|
| ±2.5% LED current regulation | Maintains consistent luminance across input voltage, temperature, and LED forward-voltage drift without closed-loop feedback compensation. |
| 5000:1 PWM dimming at 100Hz | Enables flicker-free, high-contrast illumination in machine vision inspection systems where microsecond-level timing precision is required. |
| Silent Switcher® + spread spectrum | Reduces peak EMI by >10dB compared to conventional boost converters, simplifying compliance with CISPR 25 Class 5 automotive standards. |
| Integrated open/short LED protection | Automatically detects and reports LED string faults via FAULT pin, eliminating need for external monitoring circuitry in safety-critical lighting. |
| Multi-topology operation (boost/buck/buck-boost) | Supports flexible power architecture design: boost for standard LED strings, buck for low-Vf arrays, buck-boost for variable-input applications like 12V/24V dual-rail systems. |
Applications
| Automotive Exterior Lighting | Machine Vision Illumination |
|---|---|
Use Scenario: Adaptive front-lighting systems (AFS) and dynamic turn signals requiring precise, fast-response LED current control under varying battery voltage (6V–16V). IC Role / Device Role / Timing Role: Primary synchronous boost LED driver regulating current for 6–12 LED strings, with PWM dimming synchronized to camera exposure timing. Use Value: ±2.5% current accuracy ensures consistent beam intensity; 5000:1 dimming enables smooth transition between DRL and high-beam modes without visible stepping. |
Use Scenario: High-speed industrial cameras capturing moving parts at >1000 fps, requiring strobed LED illumination with sub-microsecond edge fidelity. IC Role / Device Role / Timing Role: Constant-current LED driver with externally triggered PWM dimming via PWMTG output driving high-speed PMOS switch. Use Value: 110ns PWM-to-PWMTG propagation delay and 100% duty-cycle capability ensure accurate, jitter-free strobe timing aligned to camera trigger signals. |
| Industrial Panel Backlighting | UV-C LED Disinfection Systems |
Use Scenario: Large-format HMI displays in factory automation panels needing uniform brightness over wide temperature range (–40°C to +85°C ambient). IC Role / Device Role / Timing Role: Boost converter powering parallel LED strings with analog dimming via CTRL voltage and FB-based overvoltage protection. Use Value: Integrated 2V VREF and ±2% output voltage regulation prevent overvoltage stress on LEDs during thermal derating; thermal shutdown protects against enclosure overheating. |
Use Scenario: Portable UV-C disinfection wands using high-voltage, low-current LED arrays (30–34V, 100–300mA) powered from Li-ion batteries. IC Role / Device Role / Timing Role: Synchronous boost driver delivering regulated current to UV-C LEDs while monitoring string health via ISP/ISN and FAULT reporting. Use Value: 34V max LED string voltage accommodates series-connected UV-C diodes; open/short detection prevents hazardous operation if LED fails open or shorts. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar LED driver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LT3762EUFD#PBF | Higher 5A switch rating, wider 3V–60V input, but no integrated PWM generator or Silent Switcher® EMI reduction. | Better suited for high-power (>20W) LED arrays; lacks internal PWM dimming and requires external oscillator for sync. | Select LT3762 when output current >2A is required and EMI constraints are less stringent; LT3922IUFD#TRPBF preferred for compact, low-EMI, mid-power designs with integrated dimming. |
| MAX20050ATPA/VY+ | Automotive AEC-Q100 qualified, 2.5A/42V, but only 200kHz–2.2MHz sync range and no spread spectrum; uses different CTRL interface (I²C). | Targets ASIL-B automotive systems requiring qualification; lacks analog CTRL pin and relies on digital configuration. | Choose MAX20050 for AEC-Q100-compliant designs requiring I²C control and functional safety; LT3922IUFD#TRPBF offers simpler analog/digital hybrid control and superior EMI performance. |
Compared with LT3762EUFD#PBF and MAX20050ATPA/VY+, the LT3922IUFD#TRPBF uniquely combines ±2.5% current accuracy, 5000:1 analog+PWM dimming, Silent Switcher® EMI suppression, and integrated open/short fault reporting in a single 4mm × 5mm QFN-making it optimal for space-constrained, high-reliability LED lighting where precision, low noise, and robust protection are co-prioritized.
Availability
LT3922IUFD#TRPBF is available at Aetrix Electronics and suitable for automotive exterior lighting, machine vision illumination, industrial panel backlighting, and UV-C disinfection systems requiring stable component supply, long-term lifecycle support, and traceable sourcing.
Supply support for LT3922IUFD#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 industrial, automotive, communications, and healthcare markets.
The LT3922IUFD#TRPBF belongs to Analog Devices' Power by Linear™ LED driver family, engineered specifically for high-efficiency, low-EMI, and fault-resilient constant-current LED power conversion in demanding environments.
FAQ
What is the operating temperature range for the LT3922IUFD#TRPBF?
The LT3922IUFD#TRPBF is rated for a junction temperature range of –40°C to +125°C. This specification is guaranteed per the LT3922I grade, making it suitable for under-hood automotive applications and industrial environments with elevated ambient temperatures. The device includes thermal shutdown protection that activates above 150°C to prevent permanent damage.
Does the LT3922IUFD#TRPBF support synchronization to an external clock?
Yes, the LT3922IUFD#TRPBF supports external clock synchronization via the SYNC/SPRD pin, accepting input frequencies from 200kHz to 2MHz. When driven by an external clock, the internal oscillator is overridden, enabling deterministic switching alignment across multiple converters to reduce beat frequencies and system-level EMI. An RT resistor must still be installed to set nominal frequency behavior.
How does the LT3922IUFD#TRPBF implement LED open-circuit and short-circuit protection?
The LT3922IUFD#TRPBF monitors FB voltage and ISP–ISN differential simultaneously. An open-circuit condition is flagged when FB exceeds 1.140V while ISP–ISN falls below 10mV; a short-circuit is detected when ISP–ISN exceeds 150mV for >300µs or reaches >700mV. Both conditions pull the open-drain FAULT pin low, allowing host controllers to log faults or initiate safe shutdown sequences.
Can the LT3922IUFD#TRPBF operate in buck mode?
Yes, the LT3922IUFD#TRPBF supports buck, boost, and buck-boost topologies through external component reconfiguration. In buck mode, the VOUT pins connect to the input source, SW drives the LED string to ground, and the inductor bridges SW to the LED cathode. This flexibility enables single-IC solutions for diverse LED voltage requirements without redesigning the power stage.
What is the purpose of the RP pin on the LT3922IUFD#TRPBF?
The RP pin on the LT3922IUFD#TRPBF sets the frequency of the internal PWM generator used for analog-controlled dimming. Connecting a resistor from RP to GND (e.g., 28.7kΩ for ~7.8kHz) determines the PWM carrier frequency, while the voltage applied to the PWM pin (1V–2V) controls duty cycle from 0% to 100%. If external PWM is used, RP is tied to GND to disable the internal oscillator.
LT3922IUFD#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#TRPBF FAQ
1.How can I place an order for LT3922IUFD#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3922IUFD#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#TRPBF reliable?
The price and inventory of LT3922IUFD#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#TRPBF is usually 5 days.
3.What payment methods are accepted for LT3922IUFD#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3922IUFD#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3922IUFD#TRPBF?
LT3922IUFD#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3922IUFD#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#TRPBF?
For technical support, including LT3922IUFD#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3922IUFD#TRPBF requirements.
6.How does Aetrix verify that LT3922IUFD#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT3922IUFD#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#TRPBF meets industry standards.
7.What is the process for return or replacement of LT3922IUFD#TRPBF?
All LT3922IUFD#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3922IUFD#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#TRPBF part is unused and in its original packaging.
Return procedure for LT3922IUFD#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LT3922IUFD#TRPBF Tags
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