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Analog Devices Inc. LT3952AHFE#PBF
- Part No.:
- LT3952AHFE#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- LED Drivers
- Package:
- 28-TSSOP (0.173", 4.40mm Width) Exposed Pad
- Datasheet:
-
LT3952AHFE#PBF.pdf
- Description:
- IC LED DRVR RGLTR PWM 4A 28TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:837
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Product details
Overview
LT3952AHFE#PBF from Analog Devices is a 60V, 4A internal DMOS step-up DC/DC LED driver IC with integrated current/voltage regulation, programmable switching frequency (200kHz–3MHz), and AEC-Q100 qualification for automotive lighting. It supports true-color PWM dimming up to 4000:1, open-LED and short-circuit protection, and operates across 3V–42V input with –40°C to +150°C junction temperature range.
For engineers reviewing the LT3952AHFE#PBF datasheet, LT3952AHFE#PBF pinout, LT3952AHFE#PBF application, or LT3952AHFE#PBF equivalent, key selection criteria include its 60V/4A internal switch, dual current-sense monitoring (ISN/ISP and IVINP/IVINN), spread-spectrum EMI reduction, PMOS gate driver (TG), and thermal grade suitability for under-hood automotive LED systems.
Technical Context
The LT3952AHFE#PBF implements a fixed-frequency current-mode boost architecture with three independent regulation loops: output current (via ISP/ISN and CTRL), output voltage (via FB), and input current (via IVINP/IVINN). Its VC node serves as a wired-OR summing point where auxiliary loops only clamp-never boost-the control voltage.
It integrates a 60V, 80mΩ NMOS power switch, a 750mΩ PMOS gate driver (TG) for load-side disconnect, and analog/digital dimming interfaces (CTRL, PWM, DIM). Spread-spectrum modulation on SYNC/SPRD reduces peak EMI without compromising efficiency, while soft-start (SS) and hiccup-mode fault recovery ensure robust startup and fault handling.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3V to 42V - supports wide automotive battery range including cold-crank (6V) and load-dump (42V) transients. |
| Output Switch Rating | 60V, 4A max - enables direct driving of high-voltage LED strings (e.g., 16× 50V LEDs) without external MOSFETs. |
| Switch On-Resistance | 80mΩ - minimizes conduction loss at full 4A load, enabling >90% efficiency in typical boost configurations. |
| Operating Junction Temp | –40°C to +150°C - qualified for under-hood automotive applications per AEC-Q100 Grade H. |
| Dimming Ratio | 4000:1 true-color PWM - preserves color consistency across full brightness range via external PWM signal or internal generator. |
| Switching Frequency | 200kHz to 3MHz - adjustable via RT resistor or synchronizable to external clock; higher frequencies reduce inductor size. |
| Current Sense Accuracy | ±2% full-scale (250mV typ) - ensures precise LED current regulation critical for display backlight uniformity and headlamp photometry. |
Pinout & Package
LT3952AHFE#PBF is housed in a thermally enhanced 28-lead TSSOP package (FE) with exposed pad (Pin 29) soldered to PCB ground for thermal and electrical integrity. θJA = 30°C/W.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| GND (Pins 1, 12, 28, 29) | Ground reference and thermal sink | Exposed pad (Pin 29) must be soldered to large copper pour for thermal management and low-impedance return path. |
| SW (Pins 2, 3, 4) | Internal NMOS switch drain | High di/dt node; requires minimized copper area to reduce EMI and parasitic inductance. |
| ISP / ISN (Pins 27 / 26) | High-side output current sense inputs | Measure LED current via external shunt; support 0V–60V common-mode range for flexible string placement. |
| CTRL (Pin 17) | Current threshold programming input | 0.2V–1.2V input sets ISP–ISN regulation threshold from 0mV to 250mV - enables analog dimming and zero-current shutdown. |
| TG (Pin 25) | PMOS gate driver output | Level-shifted inverted PWM signal driving external PMOS for LED disconnect, PWM dimming, and fault isolation. |
| FB (Pin 16) | Output voltage feedback input | Monitors output via resistor divider; triggers OPENLED flag when within 45mV of 1.2V reference and current drops below 10%. |
| PWM (Pin 20) | Digital ON/OFF and dimming control | 1.2V logic threshold; enables external PWM dimming or activates internal generator when DIM pin is configured. |
| SHORTLED / OPENLED (Pins 21 / 22) | Open-drain fault indicators | Assert low during LED overcurrent (SHORTLED) or open-circuit (OPENLED); require external pull-up for system-level fault reporting. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated 60V/4A DMOS switch | Eliminates need for external high-voltage MOSFET in most automotive LED drivers, reducing BOM count and layout complexity. |
| AEC-Q100 Grade H qualification | Validated for operation from –40°C to +150°C junction temperature, meeting automotive reliability and lifetime requirements. |
| Spread-spectrum frequency modulation | Reduces EMI peak emissions by up to 10dB without sacrificing efficiency or requiring additional filtering components. |
| Dual current sensing (output + input) | Enables simultaneous LED current regulation and input current limiting - critical for battery-fed systems with strict input surge constraints. |
| Programmable open-LED and short-circuit protection | Hardware-based fault detection with dedicated flags (OPENLED/SHORTLED) enables fail-safe system response without MCU intervention. |
| Internal PWM generator with DIM control | Delivers 4000:1 PWM dimming using only a single capacitor on PWM pin - ideal for I/O-constrained microcontrollers. |
Applications
| Automotive Headlamps | Avionic Cabin Lighting |
|---|---|
Use Scenario: High-brightness adaptive front-lighting systems (AFS) requiring precise current regulation and thermal robustness under hood. IC Role / Device Role / Timing Role: Primary LED current source and fault manager; regulates 4A through 60V LED strings while monitoring open/short conditions in real time. Use Value: Enables AEC-Q100-compliant, single-chip solution for DRL and high-beam modules with no external switch or complex protection circuitry. | Use Scenario: Dimmable, EMI-sensitive interior lighting in commercial aircraft cabins with strict DO-160 compliance. IC Role / Device Role / Timing Role: Constant-current LED driver with spread-spectrum modulation and 4000:1 dimming for flicker-free ambient lighting control. Use Value: Meets aviation EMI limits without added shielding, while maintaining color fidelity across full dimming range via true-color PWM. |
| Industrial Display Backlighting | Heavy-Duty Vehicle Lighting |
Use Scenario: Large-format LCD backlights in outdoor kiosks or industrial HMIs exposed to wide temperature swings and vibration. IC Role / Device Role / Timing Role: Boost controller delivering stable 333mA to 16-LED string (57V open-circuit), with open-LED detection and thermal derating. Use Value: Ensures uninterrupted operation across –40°C to +85°C ambient via 150°C-rated silicon and robust fault recovery (hiccup mode). | Use Scenario: LED work lamps and beacon lights on construction equipment operating with 24V nominal but 16–32V transient input. IC Role / Device Role / Timing Role: Input-current-limited LED driver using IVINP/IVINN sensing to prevent battery overload during cold cranking. Use Value: Prevents brown-out by clamping input current at 4A while maintaining regulated LED output - critical for safety-critical lighting. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar LED driver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3783EFE#PBF | 40V max switch voltage, no integrated 4A switch; requires external MOSFET; supports SEPIC/Cuk topologies. | Better suited for multi-topology designs or lower-voltage LED arrays (<40V); lacks AEC-Q100 qualification. | Select when topology flexibility or lower cost per watt outweighs integration and automotive qualification needs. |
| LM3423MH/NOPB | 60V switch, but only 2.5A rating; no spread spectrum; limited to –40°C to +125°C; no IVINP/IVINN input current sensing. | Appropriate for non-automotive industrial LED drivers where thermal margin and input current limiting are not required. | Choose for cost-sensitive, non-automotive applications needing basic 60V boost capability without advanced protection or EMI features. |
Compared with LTC3783EFE#PBF and LM3423MH/NOPB, the LT3952AHFE#PBF delivers higher integration (60V/4A switch), broader temperature range (–40°C to +150°C), and automotive-grade reliability - making it the optimal choice for space-constrained, thermally demanding LED systems requiring minimal external components and certified fault resilience.
Availability
LT3952AHFE#PBF is available at Aetrix Electronics and suitable for automotive headlamps, avionic cabin lighting, and industrial display backlighting requiring stable component supply across extended temperature and long product lifecycles.
Supply support for LT3952AHFE#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 LT3952A product line delivers highly integrated, thermally robust LED drivers optimized for automotive lighting systems requiring AEC-Q100 qualification, precise current regulation, and comprehensive fault protection.
FAQ
What is the maximum junction temperature rating for the LT3952AHFE#PBF?
The LT3952AHFE#PBF is rated for continuous operation from –40°C to +150°C junction temperature and is AEC-Q100 qualified for automotive Grade H applications. This rating is confirmed in the Absolute Maximum Ratings table and applies specifically to the "H" grade variant, distinguishing it from the "E" (–40°C to +125°C) and "I" (–40°C to +125°C, guaranteed) grades.
Does the LT3952AHFE#PBF support both analog and PWM dimming simultaneously?
Yes, the LT3952AHFE#PBF supports combined analog/PWM dimming via the CTRL pin: applying a voltage between 0.1V and 0.125V enables auxiliary PWM input functionality on CTRL, allowing analog current scaling and digital PWM switching on a single pin. This feature is documented in the Electrical Characteristics table under "CTRL PWM Shutdown Threshold" and "CTRL PWM Threshold Hysteresis".
How does the LT3952AHFE#PBF implement open-LED protection?
The LT3952AHFE#PBF detects open-LED conditions by monitoring both FB voltage and output current: when FB rises within 45mV of its 1.2V regulation threshold *and* ISMON indicates LED current has dropped below 10% of full scale, the OPENLED pin asserts low. This dual-condition detection prevents false triggers during transient overvoltage events and is explicitly defined in the Pin Functions section for Pin 22.
Can the LT3952AHFE#PBF drive LEDs directly without an external PMOS transistor?
No - the LT3952AHFE#PBF requires an external PMOS transistor driven by the TG pin for LED on/off control, PWM dimming, and output disconnect during fault conditions. The TG output is an inverted, level-shifted signal referenced to ISP, capable of driving the gate of a PMOS placed between ISP and the LED cathode. This architecture is detailed in the Pin Functions description for Pin 25 and the Typical Application schematic.
What is the purpose of the IVINP and IVINN pins on the LT3952AHFE#PBF?
The IVINP and IVINN pins form an auxiliary current-sense amplifier that monitors input current independently of the main LED current loop. When the differential voltage across an external sense resistor exceeds 60mV, the IC reduces VC to limit input current - a critical feature for protecting batteries or upstream converters during inrush or overload. This function is specified in the Electrical Characteristics table under "IVIN Regulation Threshold" and described in Pin Functions for Pins 6 and 5.
LT3952AHFE#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- True Color PWM™
- Package/Case:
- 28-TSSOP (0.173", 4.40mm Width) Exposed Pad
- Packaging:
- Tube
- Product Status:
- Active
- Type:
- DC DC Regulator
- Topology:
- Step-Up (Boost)
- Internal Switch(s):
- Yes
- Number of Outputs:
- 1
- Voltage - Supply (Min):
- 3V
- Voltage - Supply (Max):
- 42V
- Voltage - Output:
- 60V
- Current - Output / Channel:
- 4A (Switch)
- Frequency:
- 215kHz ~ 3MHz
- Dimming:
- Analog, PWM
- Applications:
- Backlight
- Operating Temperature:
- -40°C ~ 150°C (TJ)
- Grade:
- Automotive
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 28-TSSOP-EP
LT3952AHFE#PBF FAQ
1.How can I place an order for LT3952AHFE#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3952AHFE#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 LT3952AHFE#PBF reliable?
The price and inventory of LT3952AHFE#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3952AHFE#PBF is usually 5 days.
3.What payment methods are accepted for LT3952AHFE#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3952AHFE#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3952AHFE#PBF?
LT3952AHFE#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3952AHFE#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 LT3952AHFE#PBF?
For technical support, including LT3952AHFE#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3952AHFE#PBF requirements.
6.How does Aetrix verify that LT3952AHFE#PBF is sourced from the original manufacturer or authorized distributors?
All LT3952AHFE#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 LT3952AHFE#PBF meets industry standards.
7.What is the process for return or replacement of LT3952AHFE#PBF?
All LT3952AHFE#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3952AHFE#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 LT3952AHFE#PBF part is unused and in its original packaging.
Return procedure for LT3952AHFE#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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