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Analog Devices Inc. LT3932IUFD-1#PBF
- Part No.:
- LT3932IUFD-1#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- LED Drivers
- Package:
- 28-WFQFN Exposed Pad
- Datasheet:
-
LT3932IUFD-1#PBF.pdf
- Description:
- IC LED DRIVER RGLTR PWM 2A 28QFN
- Quantity:
- Payment:
- Shipping:
Inventory:3,744
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Product details
Overview
LT3932IUFD-1#PBF from Analog Devices is a 36V, 2A synchronous step-down LED driver with internal PWM dimming, ±1.5% LED current regulation, and AEC-Q100 qualification for automotive lighting. It supports analog/duty-cycle LED current control (20:1 range), 5000:1 external PWM dimming at 100Hz, and operates from 3.6V to 36V input across –40°C to 125°C.
For engineers reviewing the LT3932IUFD-1#PBF datasheet, LT3932IUFD-1#PBF pinout, LT3932IUFD-1#PBF application, or LT3932IUFD-1#PBF equivalent, key selection criteria include its 28-pin 4mm × 5mm QFN package, Silent Switcher® architecture for low EMI, programmable 200kHz–2MHz switching frequency, and support for both external high-side PMOS PWM dimming and internal PWM generation.
Technical Context
The LT3932IUFD-1#PBF implements fixed-frequency peak-current-mode control with dual power switches and integrated gate drivers. Its current regulation loop uses a transconductance amplifier (200 µA/V) comparing ISP/ISN sense voltage against CTRL-derived reference, while voltage regulation overrides via FB pin when output exceeds 1.05V.
It features dual dimming paths: external PWM pulses applied to PWM pin drive PWMTG output for high-side PMOS control, or DC voltage on PWM pin (1.0V–2.0V) combined with RP resistor sets internal PWM frequency (7.4–128 kHz) and duty ratio (0–100%). The LT3932-1 variant enables higher dimming ratios than standard LT3932.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3.6V to 36V - supports wide automotive battery and industrial supply rails without pre-regulation. |
| Max Output Current | 2A - delivers sufficient drive for multi-LED strings in headlamps and machine vision illumination. |
| LED Current Accuracy | ±1.5% - ensures consistent brightness and color matching across production units. |
| Switching Frequency | 200kHz to 2MHz - selectable via RT resistor or SYNC clock; enables compact magnetics and EMI optimization. |
| PWM Dimming Ratio | 5000:1 (external), 128:1 (internal) - meets stringent contrast requirements in automotive adaptive driving beams. |
| Operating Temp Range | –40°C to +125°C - qualified per AEC-Q100 Grade I for under-hood and exterior lighting applications. |
| Package | 28-pin 4mm × 5mm QFN with exposed thermal pad - provides low θJA (25°C/W) for thermally constrained PCB layouts. |
Pinout & Package
LT3932IUFD-1#PBF is housed in a thermally enhanced 28-pin (4mm × 5mm) plastic QFN package (UFD) with exposed GND pad (Pin 29) requiring soldering to PCB for thermal and electrical integrity.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN (Pins 1, 2, 4, 5, 14) | Input Power Supply | Supplies analog circuitry and inductor current during top-switch conduction; requires local 2.2µF ceramic bypass. |
| ISP / ISN (Pins 6, 7) | Current Sense Inputs | Differential inputs to 200 µA/V error amplifier; sense voltage range 4–101.5 mV maps to 5–100% LED current. |
| CTRL (Pin 15) | LED Current Programming | Accepts 250mV–1.25V analog voltage or 100kHz–1MHz pulse (12.5–62.5% duty) to set regulated current. |
| PWM (Pin 22) | Dimming Control Input | DC voltage (1.0–2.0V) selects internal PWM duty; digital pulse enables external high-side PMOS switching. |
| PWMTG (Pin 23) | High-Side PMOS Gate Driver | Open-drain output capable of 10–11V swing (VOUT–VPWMTG); drives external PMOS for precise PWM dimming. |
| FB (Pin 4) | Output Voltage Feedback | Monitors LED string voltage via resistor divider; triggers overvoltage lockout at 1.05V and fault reporting at 0.18–0.97V. |
| FAULT (Pin 8) | Open/Short-Circuit Indicator | Open-drain output pulled low for open-circuit (FB > 950mV + ISMON < 10mV) or short-circuit (FB < 200mV). |
Key Features
| Feature | Design Value |
|---|---|
| Silent Switcher® Architecture | Minimizes EMI/EMC emissions via symmetrical layout and integrated hot-loop capacitors - reduces need for shielding and filtering. |
| Spread-Spectrum Frequency Modulation | Reduces peak EMI by varying switching frequency ±25% around programmed value when SYNC/SPRD = 3.3V. |
| Accurate LED Current Monitor (ISMON) | Provides buffered 10× scaled replica of ISP–ISN voltage (10mV/mV) for real-time current diagnostics and closed-loop feedback. |
| Programmable UVLO with Hysteresis | EN/UVLO threshold = 1.15V (rising), 1.09V (falling) with 20mV hysteresis - prevents erratic startup during battery sag. |
| Thermal Shutdown Protection | Activates above 150°C junction temperature and recovers automatically after cooldown - safeguards against sustained overload. |
Applications
| Automotive Headlamps | Industrial Machine Vision Lighting |
|---|---|
|
Use Scenario: Adaptive front-lighting systems requiring dynamic beam shaping and high-contrast dimming. IC Role / Device Role / Timing Role: Primary LED current regulator and PWM dimming controller for high-brightness LED arrays. Use Value: 5000:1 external PWM dimming ratio and ±1.5% current accuracy enable pixel-level intensity control in matrix LED headlamps. |
Use Scenario: High-speed inspection systems needing strobed, uniform illumination synchronized to camera exposure. IC Role / Device Role / Timing Role: Synchronous step-down driver with precise current regulation and fast PWM response for strobe timing. Use Value: 7.8kHz internal PWM frequency and <200ns propagation delay ensure sub-millisecond LED turn-on/off for accurate motion capture. |
| Commercial Signage Backlighting | Medical Endoscopic Illumination |
|
Use Scenario: Large-area LED panels requiring stable brightness across wide ambient temperature ranges. IC Role / Device Role / Timing Role: Constant-current LED driver with analog dimming interface and thermal derating capability. Use Value: –40°C to +125°C operating range and ±1.2% output voltage regulation maintain consistent luminance in outdoor enclosures. |
Use Scenario: Sterilizable endoscope light engines demanding high reliability, low EMI, and precise intensity control. IC Role / Device Role / Timing Role: Low-noise, AEC-Q100 qualified LED driver with fault reporting for safety-critical illumination. Use Value: Open/short LED protection and FAULT pin reporting enable real-time diagnostics and fail-safe shutdown in medical devices. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar LED driver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LT3932IUFD#PBF | Lacks -1 suffix; supports only up to 1000:1 external PWM dimming vs. 5000:1 in LT3932IUFD-1#PBF. | Not suitable for adaptive driving beam systems requiring ultra-high dimming ratios. | Select LT3932IUFD-1#PBF when >1000:1 dimming resolution is required; otherwise LT3932IUFD#PBF offers cost advantage. |
| LM3409QMY/NOPB | Lower max current (1.5A), no internal PWM generator, no spread-spectrum modulation, non-AEC-Q100. | Targeted at cost-sensitive industrial lighting, not automotive-grade systems. | Choose LM3409QMY/NOPB for non-automotive applications where EMI and dimming ratio are less critical. |
Compared with LT3932IUFD#PBF, the LT3932IUFD-1#PBF delivers 5× higher external PWM dimming ratio and maintains AEC-Q100 compliance, while LM3409QMY/NOPB trades automotive qualification and advanced dimming for lower BOM cost in non-safety-critical lighting.
Availability
LT3932IUFD-1#PBF is available at Aetrix Electronics and suitable for automotive lighting, industrial machine vision, and medical endoscopic illumination requiring stable component supply, AEC-Q100 qualification, and high-precision LED current regulation.
Supply support for LT3932IUFD-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 automotive, industrial, communications, and healthcare markets.
The LT3932 family is designed specifically for high-efficiency, low-EMI LED driving in demanding environments - emphasizing precision current regulation, robust fault protection, and automotive-grade reliability.
FAQ
What distinguishes LT3932IUFD-1#PBF from the standard LT3932IUFD#PBF?
The LT3932IUFD-1#PBF supports up to 5000:1 external PWM dimming ratio at 100Hz, whereas the standard LT3932IUFD#PBF is limited to 1000:1. This higher ratio enables finer intensity control in adaptive driving beam systems. Both share identical pinout, package, and AEC-Q100 qualification, but the -1 variant is optimized for ultra-high-contrast applications requiring extended dimming resolution. LT3932IUFD-1#PBF retains all other specifications including ±1.5% LED current accuracy and Silent Switcher® EMI performance.
How does the LT3932IUFD-1#PBF implement internal PWM dimming without an external signal?
The LT3932IUFD-1#PBF generates internal PWM signals using its on-chip oscillator and RP resistor network. When a resistor (e.g., 28.7kΩ) is connected from RP pin to GND, and a DC voltage between 1.0V and 2.0V is applied to the PWM pin, the IC produces a corresponding duty-ratio PWM waveform at PWMTG output. For example, 1.1V yields ~10% duty, 1.9V yields ~90%. This eliminates need for external PWM generators in space-constrained designs. LT3932IUFD-1#PBF supports frequencies from 7.4kHz to 128Hz depending on RP value.
Can LT3932IUFD-1#PBF operate safely with LED string voltages up to 36V?
Yes - the LT3932IUFD-1#PBF supports 0V to 36V LED string voltage (VOUT) and integrates overvoltage protection that disables switching if FB pin voltage exceeds 1.05V. Its ISP/ISN pins tolerate common-mode voltages up to 36V, enabling direct sensing across high-voltage LED strings. Combined with 36V maximum input rating and 99.9% maximum duty cycle, LT3932IUFD-1#PBF is engineered for single-stage buck operation across full automotive battery range (cold crank to load dump) without external pre-regulators.
What thermal management provisions does LT3932IUFD-1#PBF include?
LT3932IUFD-1#PBF features an exposed thermal pad (Pin 29) that must be soldered to the PCB ground plane to achieve θJA = 25°C/W. It incorporates thermal shutdown that activates above 150°C junction temperature and auto-recovers after cooldown. The device also includes thermal derating behavior: continuous operation above 125°C reduces lifetime and requires design margining. Layout best practices - such as minimizing thermal resistance from die to copper and using multiple vias under the exposed pad - are essential to sustain 2A output in high-ambient environments. LT3932IUFD-1#PBF's specification guarantees performance from –40°C to +125°C.
How does the FAULT pin indicate open-circuit versus short-circuit conditions?
The FAULT pin on LT3932IUFD-1#PBF is an open-drain output pulled low under two distinct fault conditions: (1) Open-circuit - when FB voltage rises above 950mV *and* ISMON output falls below 10mV (indicating zero current), or (2) Short-circuit - when FB voltage drops below 200mV (indicating near-zero LED string voltage). These thresholds are internally trimmed and specified over temperature. The FAULT signal remains asserted until the condition clears or the part resets via EN/UVLO cycling. This dual-threshold detection allows unambiguous fault diagnosis in automated lighting systems. LT3932IUFD-1#PBF provides this functionality without external comparators.
LT3932IUFD-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 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-1#PBF FAQ
1.How can I place an order for LT3932IUFD-1#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3932IUFD-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 LT3932IUFD-1#PBF reliable?
The price and inventory of LT3932IUFD-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 LT3932IUFD-1#PBF is usually 5 days.
3.What payment methods are accepted for LT3932IUFD-1#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3932IUFD-1#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3932IUFD-1#PBF?
LT3932IUFD-1#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3932IUFD-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 LT3932IUFD-1#PBF?
For technical support, including LT3932IUFD-1#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3932IUFD-1#PBF requirements.
6.How does Aetrix verify that LT3932IUFD-1#PBF is sourced from the original manufacturer or authorized distributors?
All LT3932IUFD-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 LT3932IUFD-1#PBF meets industry standards.
7.What is the process for return or replacement of LT3932IUFD-1#PBF?
All LT3932IUFD-1#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3932IUFD-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 LT3932IUFD-1#PBF part is unused and in its original packaging.
Return procedure for LT3932IUFD-1#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LT3932IUFD-1#PBF Tags
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BCR402RE6327HTSA1
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BCR430UXTSA2
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BCR420UE6433HTMA1
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BCR420UE6327HTSA1
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BCR421UE6327HTSA1
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LYT1604D-TL
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HV9910CLG-G
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CL2N8-G
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BCR420UW6-7
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BCR421UW6-7
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BCR420UFD-7
Diodes Incorporated
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BCR421UFD-7
Diodes Incorporated
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