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Analog Devices Inc. LT3932IUFD#TRPBF
- Part No.:
- LT3932IUFD#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- LED Drivers
- Package:
- 28-WFQFN Exposed Pad
- Datasheet:
-
LT3932IUFD#TRPBF.pdf
- Description:
- IC LED DRIVER RGLTR PWM 2A 28QFN
- Quantity:
- Payment:
- Shipping:
Inventory:1,540
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Product details
Overview
LT3932IUFD#TRPBF from Analog Devices is a 36V, 2A synchronous step-down LED driver with integrated PWM dimming control, ±1.5% LED current regulation, and Silent Switcher® architecture for low EMI. It supports analog or duty-cycle-based LED current programming via the CTRL pin and features open/short LED fault detection with FAULT pin reporting - used in automotive headlight modules requiring precise, high-reliability dimming.
For engineers reviewing the LT3932IUFD#TRPBF datasheet, LT3932IUFD#TRPBF pinout, LT3932IUFD#TRPBF application, or LT3932IUFD#TRPBF equivalent, key selection criteria include input voltage range (3.6V–36V), programmable switching frequency (200kHz–2MHz), internal PWM dimming capability (128:1 ratio), thermal shutdown, and AEC-Q100 qualification for automotive lighting systems.
Technical Context
The LT3932IUFD#TRPBF implements fixed-frequency peak-current-mode control with dual power switches and integrated gate drivers. Its current regulation loop uses a transconductance amplifier (gm = 200 µA/V) comparing ISP–ISN voltage against a CTRL-derived reference, while voltage regulation overrides current control when FB approaches 1.000 V.
It integrates a spread-spectrum oscillator (RT/SYNC/SPRD pins), internal PWM generator (RP-programmed, 7.4–128 kHz), and high-side PMOS driver (PWMTG) with 10–11 V gate drive swing. Fault logic monitors FB for open-circuit (>950 mV) and short-circuit (<200 mV) conditions, pulling FAULT low with 100 µA sink capability.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3.6 V to 36 V - supports wide automotive battery range including cold-crank (6 V) and load-dump (36 V) transients. |
| LED Current Accuracy | ±1.5 % - ensures consistent luminance across LED strings without external calibration. |
| Switching Frequency | 200 kHz to 2 MHz - adjustable via RT resistor or external SYNC clock; enables EMI optimization and compact magnetics. |
| Internal PWM Dimming Ratio | 128:1 - provides fine-grained brightness control using RP-resistor-set frequency and PWM pin voltage (1.0–2.0 V). |
| Output Voltage Limit | Programmable via FB divider - protects LED string from overvoltage by disabling switching at 1.05 V FB threshold. |
| Operating Junction Temp | –40°C to +125°C - qualified per AEC-Q100 Grade I, suitable for under-hood automotive lighting environments. |
| Package | 28-pin (4 mm × 5 mm) QFN with exposed thermal pad - enables efficient heat dissipation in space-constrained PCB layouts. |
Pinout & Package
LT3932IUFD#TRPBF is housed in a thermally enhanced 28-lead plastic QFN (4 mm × 5 mm), with exposed pad (Pin 29) soldered to PCB ground for thermal and electrical integrity. θJA = 25°C/W measured on DC2286A evaluation board.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN (Pins 1, 4, 5, 14, 17) | Input Power Supply | Supplies analog circuitry and inductor current during top-switch conduction; requires local 2.2 µF ceramic bypass to GND. |
| ISP / ISN (Pins 6, 7) | Current Sense Inputs | Differential inputs to sense voltage across external sense resistor (e.g., 50 mΩ); common-mode range 0–36 V supports high-side sensing. |
| CTRL (Pin 15) | LED Current Programming | Accepts analog voltage (250–1250 mV) or digital pulse (100–1000 kHz, 12.5–62.5% duty) to set regulated LED current. |
| FB (Pin 4) | Output Voltage Feedback | Monitors LED string voltage via resistor divider; triggers overvoltage lockout at 1.05 V and fault reporting at <200 mV (short) or >950 mV (open). |
| PWM / RP / PWMTG (Pins 22, 9, 12) | Dimming Control Interface | PWM pin accepts external signal or sets internal PWM duty (1–2 V); RP sets internal PWM frequency; PWMTG drives external high-side PMOS gate. |
| FAULT (Pin 8) | Open/Short Fault Indicator | Open-drain output pulled low during LED open-circuit (FB > 950 mV + ISP–ISN < 10 mV) or short-circuit (FB < 200 mV). |
Key Features
| Feature | Design Value |
|---|---|
| Silent Switcher® architecture | Minimizes EMI/EMC emissions via balanced layout and integrated input capacitors - reduces need for external EMI filters in automotive designs. |
| Integrated PWM dimming generator | Eliminates need for external PWM controller IC; RP-resistor sets frequency (7.4–128 kHz), PWM pin voltage sets duty (0–100%) - simplifies BOM and layout. |
| Accurate LED current monitor (ISMON) | Provides buffered 10× scaled replica of ISP–ISN voltage (e.g., 100 mV sense → 1.00 V ISMON) - enables real-time current diagnostics without signal conditioning. |
| Programmable UVLO with hysteresis | EN/UVLO threshold = 1.15 V (rising), 1.09 V (falling), 20 mV hysteresis - ensures clean startup/shutdown during battery voltage sag or recovery. |
| Thermal shutdown protection | Activates at junction temperature >150°C (LT3932I grade), with automatic recovery after cooldown - prevents permanent damage during overload or poor heatsinking. |
Applications
| Automotive Headlights | Industrial Machine Vision Lighting |
|---|---|
|
Use Scenario: Adaptive front-lighting system (AFS) with dynamic beam shaping and daytime running light (DRL) dimming. IC Role / Device Role / Timing Role: Primary LED current regulator and PWM dimming controller; manages up to 2 A string current with ±1.5% accuracy and 128:1 dimming ratio. Use Value: Enables compliance with UNECE R149 photometric requirements through precise, repeatable current control and fast PWM response (100 ns propagation delay). |
Use Scenario: High-speed inspection systems requiring strobed LED illumination synchronized to camera exposure. IC Role / Device Role / Timing Role: Synchronous LED driver with external PWM gating via PWMTG; supports external trigger input and internal PWM generation for flexible timing. Use Value: Delivers sub-microsecond PWM edge control and stable current during rapid on/off cycling - eliminates image blur and ensures consistent illumination intensity. |
| Commercial Architectural Lighting | Medical Endoscopic Illumination |
|
Use Scenario: DALI- or 0–10 V-controlled LED troffers and downlights in office and retail spaces. IC Role / Device Role / Timing Role: Constant-current LED driver accepting analog 0–10 V or PWM input; regulates current via CTRL pin with 20:1 analog control range. Use Value: Achieves flicker-free dimming down to 0.5% output using combined analog + PWM control - meets IEEE 1789-2015 low-risk flicker guidelines. |
Use Scenario: Compact, sterilizable endoscope light engines requiring low-EMI, thermally robust LED drive. IC Role / Device Role / Timing Role: High-efficiency (≥95% at 1 A) step-down driver with Silent Switcher® EMI reduction and 125°C operation. Use Value: Reduces conducted/radiated noise that could interfere with adjacent imaging sensors or RF telemetry - critical for FDA Class II medical device EMC compliance. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar LED driver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LT3932EUFD#TRPBF | Same silicon, –40°C to +125°C operating range (Grade E vs Grade I); identical electrical specs and pinout. | Not AEC-Q100 qualified; intended for industrial, not automotive, use cases. | Select LT3932IUFD#TRPBF for automotive applications requiring AEC-Q100 Grade I reliability; choose LT3932EUFD#TRPBF only for non-automotive designs with identical performance needs. |
| LT3932-1IUFD#TRPBF | Enhanced version supporting ≥5000:1 PWM dimming ratio (vs 128:1); same package, pinout, and thermal rating. | Enables ultra-low-light operation (e.g., night vision modes) where deeper dimming is required beyond standard 128:1 capability. | Choose LT3932-1IUFD#TRPBF when >1000:1 dimming is mandatory; otherwise, LT3932IUFD#TRPBF offers optimal cost/performance for standard automotive lighting. |
Compared with LT3932EUFD#TRPBF, the LT3932IUFD#TRPBF adds AEC-Q100 qualification and tighter production testing for automotive use, while LT3932-1IUFD#TRPBF extends dimming resolution - making the base LT3932IUFD#TRPBF the preferred choice for cost-sensitive, Grade I-compliant headlight and DRL systems.
Availability
LT3932IUFD#TRPBF is available at Aetrix Electronics and suitable for automotive lighting, industrial machine vision systems, and commercial architectural LED applications requiring stable component supply, AEC-Q100 compliance, and long-term production continuity.
Supply support for LT3932IUFD#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 automotive, industrial, communications, and healthcare markets with precision power and signal chain solutions.
The LT3932IUFD#TRPBF belongs to Analog Devices' Silent Switcher LED driver product line, engineered specifically for automotive-grade, low-EMI constant-current LED regulation in safety-critical lighting systems.
FAQ
What is the maximum LED string voltage supported by the LT3932IUFD#TRPBF?
The LT3932IUFD#TRPBF supports 0 V to 36 V LED string voltage, with output voltage limit programmable via the FB pin resistor divider. The internal overvoltage protection disables switching when FB reaches 1.05 V, preventing damage to LEDs during transient overvoltage events. This allows safe operation across diverse LED configurations - from single high-brightness emitters to multi-LED strings in automotive forward lighting.
Does the LT3932IUFD#TRPBF require an external PWM controller for dimming?
No, the LT3932IUFD#TRPBF integrates a complete PWM dimming subsystem: the RP pin sets internal PWM frequency (7.4–128 kHz), the PWM pin accepts either an external logic signal or a DC voltage (1.0–2.0 V) to define duty cycle (0–100%), and the PWMTG pin drives an external high-side PMOS. This eliminates the need for a separate PWM controller IC, reducing system complexity and PCB area in designs like adaptive driving beams.
How does the LT3932IUFD#TRPBF handle LED open-circuit and short-circuit faults?
The LT3932IUFD#TRPBF continuously monitors FB voltage and ISP–ISN differential. An open-circuit condition (FB > 950 mV + ISP–ISN < 10 mV) or short-circuit (FB < 200 mV) pulls the open-drain FAULT pin low with 100 µA sink capability. This signal can directly interface with microcontroller GPIOs or system supervisors to trigger fail-safe responses such as lamp-off or diagnostic logging - critical for ASIL-B compliant lighting systems.
Can the LT3932IUFD#TRPBF operate from a 12 V automotive battery during cranking?
Yes, the LT3932IUFD#TRPBF operates from 3.6 V to 36 V input, covering full automotive battery range including cold-crank dips down to ~6 V. Its EN/UVLO pin has a guaranteed 300 mV shutdown threshold and 1.09–1.21 V enable threshold with 20 mV hysteresis, ensuring reliable restart after voltage recovery without oscillation - essential for headlight systems that must remain functional during engine start.
What thermal performance can be expected from the LT3932IUFD#TRPBF in a typical 2-layer PCB layout?
On a standard 2-layer PCB with 1 oz copper and the exposed thermal pad (Pin 29) fully soldered to a 2 cm² internal ground plane, the LT3932IUFD#TRPBF achieves θJA ≈ 25°C/W (per DC2286A evaluation board data). At 2 A LED current and 12 V input, typical power dissipation is <1.2 W - resulting in ~30°C junction-to-ambient rise, well within the –40°C to +125°C operating range and enabling fanless operation in sealed headlamp housings.
LT3932IUFD#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 Regulator
- Topology:
- Step-Down (Buck)
- Internal Switch(s):
- Yes
- Number of Outputs:
- 1
- Voltage - Supply (Min):
- 3.6V
- Voltage - Supply (Max):
- 36V
- Voltage - Output:
- -
- Current - Output / Channel:
- 2A
- 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)
LT3932IUFD#TRPBF FAQ
1.How can I place an order for LT3932IUFD#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3932IUFD#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 LT3932IUFD#TRPBF reliable?
The price and inventory of LT3932IUFD#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3932IUFD#TRPBF is usually 5 days.
3.What payment methods are accepted for LT3932IUFD#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3932IUFD#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3932IUFD#TRPBF?
LT3932IUFD#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3932IUFD#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 LT3932IUFD#TRPBF?
For technical support, including LT3932IUFD#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3932IUFD#TRPBF requirements.
6.How does Aetrix verify that LT3932IUFD#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT3932IUFD#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 LT3932IUFD#TRPBF meets industry standards.
7.What is the process for return or replacement of LT3932IUFD#TRPBF?
All LT3932IUFD#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3932IUFD#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 LT3932IUFD#TRPBF part is unused and in its original packaging.
Return procedure for LT3932IUFD#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LT3932IUFD#TRPBF Tags
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