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Analog Devices Inc. LT3952AIFE#PBF
- Part No.:
- LT3952AIFE#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- LED Drivers
- Package:
- 28-TSSOP (0.173", 4.40mm Width) Exposed Pad
- Datasheet:
-
LT3952AIFE#PBF.pdf
- Description:
- IC LED DRVR RGLTR PWM 4A 28TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:110
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Product details
Overview
LT3952AIFE#PBF from Analog Devices is a 60V, 4A internal DMOS step-up DC/DC LED driver IC with dual current regulation (input and output), constant-voltage feedback, and integrated PMOS gate driver for load disconnect. It delivers true-color PWM dimming up to 4000:1, supports 3V–42V input, regulates output up to 60V, and features spread-spectrum frequency modulation for EMI reduction in automotive lighting and display backlighting.
For engineers reviewing the LT3952AIFE#PBF datasheet, LT3952AIFE#PBF pinout, LT3952AIFE#PBF application, or LT3952AIFE#PBF equivalent, key selection criteria include its 28-lead TSSOP thermal performance, AEC-Q100 qualification for automotive use, programmable 200kHz–3MHz switching frequency, and dual-loop regulation enabling robust high-power LED driving under variable input and load conditions.
Technical Context
The LT3952AIFE#PBF implements fixed-frequency current-mode control with slope compensation, integrating three independent regulation loops-output current (via ISP/ISN and CTRL), input current (via IVINP/IVINN and IVINCOMP), and output voltage (via FB)-wired-OR'd to limit VC and prevent overregulation. Its internal 60V/80mΩ NMOS switch enables boost topologies up to 60V output while supporting analog and PWM dimming simultaneously.
It embeds a 20μA constant-current DIM pin for triangle-wave generation, a 4× buffered ISMON output for real-time LED current monitoring, and fault flags (SHORTLED/OPENLED) with hysteresis and update gating synchronized to PWM high time-ensuring precise, responsive protection in safety-critical lighting systems.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3V to 42V - supports wide-range battery and industrial supply inputs without external pre-regulation. |
| Output Voltage Capability | 0V to 60V - enables direct drive of multi-string high-Vf LED arrays (e.g., 16× 50V LEDs) in boost configuration. |
| Switch Current Limit | 4A typical (4.5A max) - sets peak inductor current for thermal and efficiency optimization in 40W+ LED drivers. |
| Dimming Ratio | 4000:1 true-color PWM - preserves chromaticity across full brightness range via synchronous external PWM or internal generator. |
| Switching Frequency Range | 200kHz to 3MHz (adjustable via RT resistor or SYNC clock) - allows trade-off between EMI, inductor size, and efficiency. |
| Operating Temperature | –40°C to +125°C junction - qualified per AEC-Q100 Grade I for under-hood automotive lighting applications. |
| Package | 28-lead TSSOP with exposed thermal pad - provides 30°C/W θJA for reliable power dissipation at 4A switch current. |
Pinout & Package
LT3952AIFE#PBF is housed in a thermally enhanced 28-lead plastic TSSOP (FE package) with exposed GND pad (Pin 29) requiring soldering to PCB copper for thermal and electrical integrity. Pin pitch is 0.65mm; body dimensions are 9.7mm × 4.4mm × 1.1mm.
| 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 PCB copper area to maintain ≤125°C junction temperature at full load. |
| SW (Pins 2, 3, 4) | Internal NMOS switch drain nodes | Parallel connection reduces conduction loss and EMI; requires minimized copper area to limit parasitic inductance. |
| ISP / ISN (Pins 27 / 26) | High-side output current sense inputs | Measure differential voltage across external sense resistor; support 0–60V common-mode range for boost output monitoring. |
| CTRL (Pin 17) | Current threshold programming input | 0.2V–1.2V input sets ISP–ISN threshold from 0mV to 250mV, enabling 0–100% LED current scaling with 10:1 analog dimming. |
| PWM (Pin 20) | Digital ON/OFF and PWM dimming control | 1.2V logic threshold; drives internal latch and TG output; also sources/sinks ±10µA for external capacitor-based triangle wave generation. |
| TG (Pin 25) | PMOS gate driver output | Inverted, level-shifted signal drives external PMOS (e.g., Si7309) for LED load disconnect, PWM dimming, and short-circuit isolation. |
| FB (Pin 16) | Output voltage feedback input | 1.2V internal reference; used for open-LED protection (asserts OPENLED when VFB within 45mV of 1.2V and current drops to 10% full scale). |
| SHORTLED / OPENLED (Pins 21 / 22) | Open-drain fault flag outputs | Active-low indicators updated only during PWM high time; require external pull-up; sink ≤2mA for logic-level interfacing. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated 60V/80mΩ NMOS switch | Eliminates external high-voltage switch, reducing BOM count and layout complexity in 40W+ LED boost drivers. |
| 4000:1 true-color PWM dimming | Maintains consistent LED color point across full intensity range by synchronizing PWM edges with switching cycle and avoiding current ripple artifacts. |
| Spread-spectrum frequency modulation (SSFM) | Reduces peak EMI by ±1% to ±31% frequency dithering-enables compliance with CISPR 25 Class 5 without added shielding or filtering. |
| Programmable input current limit (IVINP/IVINN) | Prevents source overload using auxiliary sense resistor; protects batteries or DC supplies during cold-crank or transient events. |
| AEC-Q100 Grade I qualification | Validated for automotive ambient temperatures (–40°C to +125°C), including HTOL, TC, and ESD testing-suitable for headlamp and DRL modules. |
| Real-time current monitoring (ISMON) | 4× buffered ISP–ISN output provides instantaneous LED current feedback for closed-loop brightness control or diagnostics without ADC overhead. |
Applications
| Automotive Headlamps | Industrial Display Backlighting |
|---|---|
|
Use Scenario: High-brightness adaptive driving beam (ADB) headlamps requiring precise current control across varying battery voltage (6V–16V) and ambient temperature (–40°C to +105°C). IC Role / Device Role / Timing Role: Primary boost LED driver with dual-loop regulation, PMOS load disconnect for fail-safe shutdown, and SHORTLED/OPENLED fault reporting to vehicle CAN bus. Use Value: Enables AEC-Q100-compliant, 4000:1 dimming with <±2% current accuracy over temperature-critical for glare-free dynamic beam shaping. |
Use Scenario: Large-format LCD backlights (e.g., medical monitors, kiosks) needing uniform brightness across 12–24 parallel LED strings driven from 12V or 24V rails. IC Role / Device Role / Timing Role: Constant-current boost controller regulating total string current while using FB loop for overvoltage clamp and open-circuit detection. Use Value: Delivers stable 4A output with <1% current matching between strings and SSFM-enabled EMI reduction-eliminates need for external EMI filters in Class B environments. |
| Avionic Cabin Lighting | UV-C Sterilization Modules |
|
Use Scenario: FAA-certified LED cabin lights operating from 28V aircraft bus with strict EMI limits and thermal constraints in confined ceiling spaces. IC Role / Device Role / Timing Role: High-efficiency boost driver with spread-spectrum clocking and thermal foldback via junction temperature sensing. Use Value: Achieves >92% efficiency at 36V input/48V output while meeting RTCA/DO-160 Section 21 Level A radiated emissions-reducing system-level certification risk. |
Use Scenario: Pulsed UV-C LED arrays (275nm) requiring precise current pulses (100–500mA, 1–10kHz) for surface disinfection with minimal thermal drift. IC Role / Device Role / Timing Role: Fast-response current regulator using ISMON feedback and PWM-triggered soft-start to manage inrush and duty-cycle transients. Use Value: Maintains ±1.5% current accuracy across pulse trains and 0–85°C ambient-ensuring repeatable germicidal dose delivery without optical feedback sensors. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar high-voltage LED driver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3783EFE#PBF | 40V max output, no integrated switch, requires external MOSFET; lacks ISMON and SSFM; supports 100kHz–1MHz only. | Suitable for lower-power (<25W), non-automotive designs where board space and EMI are less constrained. | Select when cost sensitivity outweighs integration and EMI performance; requires additional gate driver and current sense amplifier. |
| LM3414HVMM/NOPB | 65V max output but only 1.5A switch current; no input current regulation or OPENLED/SHORTLED flags; no AEC-Q100 rating. | Fits basic industrial LED lighting where fault reporting and automotive qualification are not required. | Choose for simpler, lower-current applications (<20W); lacks dual-loop control and diagnostic capability of LT3952AIFE#PBF. |
Compared with LTC3783EFE#PBF and LM3414HVMM/NOPB, the LT3952AIFE#PBF uniquely integrates 4A/60V switching, AEC-Q100 qualification, real-time ISMON feedback, and spread-spectrum EMI reduction-making it the only option for compact, high-reliability automotive and avionic LED drivers demanding full-feature protection and dimming.
Availability
LT3952AIFE#PBF is available at Aetrix Electronics and suitable for automotive headlamps, industrial display backlighting, avionic cabin lighting, and UV-C sterilization modules requiring stable component supply, long-term lifecycle support, and AEC-Q100-compliant sourcing.
Supply support for LT3952AIFE#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, Inc. is a global semiconductor leader specializing in high-performance analog, mixed-signal, and digital signal processing technologies for precision instrumentation, industrial automation, and automotive systems.
The LT3952A product line is designed specifically for high-reliability, high-power LED driving in harsh environments-emphasizing integrated protection, EMI robustness, and AEC-Q100 qualification for next-generation automotive lighting and safety-critical illumination.
FAQ
What is the maximum output voltage supported by the LT3952AIFE#PBF?
The LT3952AIFE#PBF supports output voltages up to 60V, enabled by its internal 60V-rated DMOS power switch and high-side current sense architecture (ISP/ISN). This allows direct driving of high-Vf LED strings-such as 16× 50V LEDs-in boost configuration without external high-voltage components. The FB loop provides overvoltage protection up to 1.23V reference +30mV threshold.
Does the LT3952AIFE#PBF support both analog and PWM dimming simultaneously?
Yes, the LT3952AIFE#PBF supports combined analog and PWM dimming: CTRL pin adjusts full-scale current (0–100%) for 10:1 analog control, while PWM pin enables true-color 4000:1 digital dimming. Below 100mV, CTRL doubles as an auxiliary PWM input-allowing single-pin hybrid dimming without external logic. This dual-path capability is confirmed in the Functional Block Diagram and Electrical Characteristics tables.
How does the LT3952AIFE#PBF implement short-circuit and open-LED protection?
The LT3952AIFE#PBF uses dedicated open-drain flags: SHORTLED pulls low when ISP–ISN exceeds 375mV (indicating LED overcurrent), and OPENLED pulls low when FB voltage rises within 45mV of 1.2V *and* LED current falls below 10% full scale. Both flags update only during PWM high time and require external pull-up resistors-providing deterministic, noise-immune fault signaling for system-level safety monitoring.
Is the LT3952AIFE#PBF pin-compatible with earlier LT3952 variants?
No, the LT3952AIFE#PBF is not pin-compatible with non-A revisions. The "A" suffix denotes functional enhancements including improved CTRL pin linearity, tighter ISP–ISN accuracy (±2% vs ±3%), reduced SSFM step resolution, and updated fault flag timing behavior. Pin count and physical layout match the 28-lead TSSOP package, but electrical behavior and register mapping differ-requiring schematic and firmware validation for migration.
What thermal design guidance applies to the LT3952AIFE#PBF's exposed pad?
The exposed pad (Pin 29) of the LT3952AIFE#PBF must be soldered to a minimum 200mm² copper area with ≥4 thermal vias (0.3mm diameter, spaced ≤2mm apart) connecting to inner ground planes. Per the Absolute Maximum Ratings table, θJA = 30°C/W assumes this layout; insufficient copper increases junction temperature beyond the 125°C limit-triggering thermal shutdown and degrading long-term reliability in continuous 4A operation.
LT3952AIFE#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 ~ 125°C (TJ)
- Grade:
- Automotive
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 28-TSSOP-EP
LT3952AIFE#PBF FAQ
1.How can I place an order for LT3952AIFE#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3952AIFE#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 LT3952AIFE#PBF reliable?
The price and inventory of LT3952AIFE#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3952AIFE#PBF is usually 5 days.
3.What payment methods are accepted for LT3952AIFE#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3952AIFE#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3952AIFE#PBF?
LT3952AIFE#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3952AIFE#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 LT3952AIFE#PBF?
For technical support, including LT3952AIFE#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3952AIFE#PBF requirements.
6.How does Aetrix verify that LT3952AIFE#PBF is sourced from the original manufacturer or authorized distributors?
All LT3952AIFE#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 LT3952AIFE#PBF meets industry standards.
7.What is the process for return or replacement of LT3952AIFE#PBF?
All LT3952AIFE#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3952AIFE#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 LT3952AIFE#PBF part is unused and in its original packaging.
Return procedure for LT3952AIFE#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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