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Analog Devices Inc. LT3795HFE#PBF
- Part No.:
- LT3795HFE#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- LED Drivers
- Package:
- 28-TSSOP (0.173", 4.40mm Width) Exposed Pad
- Datasheet:
-
LT3795HFE#PBF.pdf
- Description:
- IC LED DRIVER CTRLR PWM 28TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:4,403
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Product details
Overview
LT3795HFE#PBF from Analog Devices is a high-voltage 110V constant-current/constant-voltage DC/DC LED controller with spread spectrum frequency modulation (SSFM), designed to drive high-power LEDs in automotive and industrial lighting systems. It features ±3% constant current regulation across 0V–110V output, 3000:1 true-color PWM dimming, and integrated PMOS gate driver for output disconnect. The device operates from 4.5V to 110V input and supports programmable input current limiting.
For engineers reviewing the LT3795HFE#PBF datasheet, LT3795HFE#PBF pinout, LT3795HFE#PBF application, or LT3795HFE#PBF equivalent, key selection criteria include its AEC-Q100 qualification for automotive use, 28-lead TSSOP package with exposed pad thermal management, –40°C to 150°C junction temperature rating, and dual analog dimming via CTRL1/CTRL2 inputs with rail-to-rail ISP/ISN common-mode range.
Technical Context
The LT3795HFE#PBF implements a fixed-frequency current-mode control architecture with internal 7.7V INTVCC regulator, enabling stable operation across wide VIN (4.5V–110V) and VOUT (0V–110V) ranges. Its error amplifier compares ISP–ISN voltage against a programmable threshold set by CTRL1/CTRL2, delivering precise LED current regulation independent of output voltage.
It integrates dedicated circuitry for system protection: OPENLED flag triggers when FB > 1.20V and V(ISP–ISN) < 25mV; SHORTLED asserts on FB < 0.3V post-startup or V(ISP–ISN) > 375mV; SS pin enables fault restart timing with 2.8µA pull-down after overcurrent, thermal, or undervoltage events.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 4.5V to 110V - supports wide-range industrial and automotive battery inputs including 48V, 60V, and transient-tolerant 110V systems. |
| Constant Current Accuracy | ±3% over 0V ≤ VOUT ≤ 110V - ensures consistent LED brightness across full output voltage swing without recalibration. |
| Switching Frequency Range | 100kHz to 1MHz - adjustable via RT resistor; enables optimization of efficiency vs. EMI trade-offs in high-power LED drivers. |
| Junction Temperature Range | –40°C to +150°C - qualified per AEC-Q100 Grade H; suitable for under-hood automotive LED headlamp and fog lamp applications. |
| PWM Dimming Ratio | 3000:1 - enables high-fidelity color-matching in RGB LED arrays and smooth low-brightness illumination without flicker. |
| Input Current Sensing | Programmable 57mV–63mV threshold - allows accurate input current limiting using external RINSENSE, critical for battery charger and power supply compliance. |
| Spread Spectrum Modulation | 70% frequency spread - reduces peak EMI emissions by spreading switching energy across bandwidth, easing EMC certification. |
Pinout & Package
LT3795HFE#PBF is housed in a 28-lead plastic TSSOP package with exposed thermal pad (Pin 29 = GND), optimized for high-power dissipation in compact LED driver designs. Thermal resistance θJA = 30°C/W and θJC = 10°C/W support reliable operation at 150°C junction temperature.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| ISP / ISN (Pins 1, 2) | LED current sense differential inputs | Kelvin-connected to RLED; 0V–110V common-mode range enables high-side sensing in boost/buck-boost topologies. |
| TG (Pin 3) | Inverted PMOS gate driver output | Drives series PMOS switch between ISP and (ISP – 7V); internal 7V clamp protects gate oxide during high-voltage transients. |
| GATE (Pin 19) | N-channel MOSFET gate driver | Switches between INTVCC (7.7V) and GND; drives low-side switch with 20ns rise/fall time into 3300pF load. |
| FB (Pin 7) | Voltage feedback / open-LED detection | Regulates to 1.25V nominal; asserts OPENLED if FB > 1.20V and V(ISP–ISN) < 25mV - detects broken LED string without additional circuitry. |
| CTRL1 / CTRL2 (Pins 6, 9) | Analog dimming threshold control | Set LED current threshold linearly from 0% to 100%; lowest voltage dominates - enables redundant dimming or temperature compensation. |
| SS (Pin 11) | Soft-start & fault timer | 28µA pull-up to 2.5V; switches to 2.8µA pull-down on fault - enables programmable restart delay without external timer IC. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated PMOS disconnect driver | Enables safe output disconnection during PWM off-time - eliminates leakage current through LED string in standby mode. |
| Programmable input current limit | 60mV threshold with ±3mV accuracy - allows precise IIN = 60mV/RINSENSE setting for battery charging and input surge protection. |
| C/10 battery charge detection | Uses ISP–ISN comparator with 25mV threshold - provides automatic termination signal for Li-ion/LiFePO4 chargers without external op-amps. |
| AEC-Q100 Grade H qualification | Validated for –40°C to +150°C operation - meets automotive reliability requirements for front-end lighting and ADAS illumination modules. |
| Rail-to-rail ISP/ISN common-mode range | 0V to 110V - supports direct sensing in high-side configurations across buck, boost, and SEPIC LED drivers without level-shifting. |
Applications
| Automotive LED Headlamps | Industrial High-Voltage LED Drivers |
|---|---|
Use Scenario: Adaptive driving beam (ADB) systems requiring precise current control across multiple LED segments under 12V–48V vehicle bus with load-dump transients. IC Role / Device Role / Timing Role: Constant-current controller managing up to 110V LED strings; TG pin drives PMOS for segment isolation; SS pin enforces fault recovery timing after overvoltage events. Use Value: ±3% current accuracy maintains consistent lumen output across temperature; AEC-Q100 H-grade ensures 15-year reliability in under-hood environments. |
Use Scenario: Outdoor signage and street lighting powered from 48V DC microgrids or PoE++ infrastructure with strict EMI limits. IC Role / Device Role / Timing Role: Primary DC/DC controller implementing spread-spectrum modulation (SSFM) and programmable frequency to meet CISPR-15 Class B radiated emissions. Use Value: 70% frequency spread reduces peak EMI by >10dB; 100kHz–1MHz tuning enables layout optimization for thermal and noise performance. |
| Battery-Powered LED Lighting | Accurate Current-Limited Voltage Regulators |
Use Scenario: Portable medical lighting and emergency beacons using Li-ion packs (3.0V–12.6V) driving high-brightness white LEDs at constant current. IC Role / Device Role / Timing Role: Dual-mode controller operating in constant-current mode for LED drive and constant-voltage mode for auxiliary 5V/3.3V rails via FB pin. Use Value: 3000:1 PWM dimming preserves color fidelity; C/10 detection (25mV threshold) enables autonomous battery charge termination without MCU intervention. |
Use Scenario: Precision lab equipment requiring stable, current-limited 5V/12V outputs with fast transient response and overcurrent foldback. IC Role / Device Role / Timing Role: Voltage-regulating controller using FB loop with ±2% regulation; SENSE pin monitors output current for programmable foldback limiting. Use Value: ±2% CV regulation and 113mV SENSE threshold enable sub-1% output tolerance; rail-to-rail ISP/ISN allows direct current monitoring in high-side configurations. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar LED controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3783EFE#PBF | Fixed 200kHz–2MHz frequency range; no SSFM; lacks PMOS TG driver and OPENLED/SHORTLED flags. | Suitable for non-automotive, lower-EMI-sensitive applications where input current limiting and fault reporting are secondary. | Select LTC3783EFE#PBF only when spread-spectrum EMI reduction and automotive diagnostics are not required. |
| LM3423MH/NOPB | Lower max input voltage (75V); no C/10 detection; CTRL dimming limited to single-input analog control. | Targeted at cost-sensitive commercial lighting; lacks AEC-Q100 qualification and 110V transient tolerance. | Choose LM3423MH/NOPB for 48V LED systems where 150°C operation and battery charge integration are unnecessary. |
Compared with LTC3783EFE#PBF and LM3423MH/NOPB, LT3795HFE#PBF uniquely combines 110V input tolerance, AEC-Q100 H-grade reliability, integrated SSFM, and dual-analog-dimming capability - making it the only option for automotive adaptive front-lighting and high-reliability industrial LED drivers demanding full diagnostic visibility.
Availability
LT3795HFE#PBF is available at Aetrix Electronics and suitable for automotive LED headlamps, industrial high-voltage signage, and battery-powered medical lighting requiring stable component supply with guaranteed long-term availability and automotive-grade traceability.
Supply support for LT3795HFE#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 industrial, automotive, communications, and healthcare markets with precision power management solutions.
The LT3795HFE#PBF belongs to Analog Devices' high-voltage LED controller product line, engineered specifically for automotive-grade, high-reliability LED lighting systems requiring robust fault protection, wide input range, and EMI-compliant operation.
FAQ
What is the maximum operating junction temperature for LT3795HFE#PBF?
The LT3795HFE#PBF is rated for a maximum junction temperature of +150°C and is fully specified over the –40°C to +150°C operating junction temperature range. This Grade H qualification meets AEC-Q100 requirements for under-hood automotive applications. Derating guidelines apply above 125°C to ensure long-term reliability; thermal design must maintain θJA ≤ 30°C/W using the exposed pad soldered to PCB ground plane.
How does LT3795HFE#PBF implement open-LED protection?
The LT3795HFE#PBF implements open-LED protection by monitoring both FB voltage and ISP–ISN differential voltage. When FB exceeds 1.20V (typical) and V(ISP–ISN) falls below 25mV (typical), the OPENLED pin asserts a low signal. This dual-condition logic prevents false triggering during startup or dimming transitions. The LT3795HFE#PBF requires an external pull-up resistor on OPENLED and updates status only during PWM high states.
Can LT3795HFE#PBF operate in constant-voltage mode?
Yes, the LT3795HFE#PBF supports constant-voltage regulation via the FB pin, which is internally regulated to 1.25V (±2%) with a transconductance amplifier driving the VC pin. In CV mode, the controller regulates output voltage while maintaining ±2% accuracy across load and line variations. The same FB pin also serves open-LED detection, allowing dual functionality without external components - a key feature of the LT3795HFE#PBF design.
What is the purpose of the TG pin on LT3795HFE#PBF?
The TG pin on the LT3795HFE#PBF is a dedicated top-gate driver that inverts and level-shifts the PWM signal to drive the gate of an external high-side PMOS transistor. It operates between ISP and (ISP – 7V), with internal clamping to protect the PMOS gate oxide. This enables safe output disconnect during PWM off-time - eliminating leakage current through the LED string and improving system efficiency in standby mode. The LT3795HFE#PBF's TG pin is essential for fail-safe LED string isolation.
Does LT3795HFE#PBF support spread-spectrum frequency modulation (SSFM)?
Yes, the LT3795HFE#PBF includes built-in spread-spectrum frequency modulation (SSFM) controlled via the RAMP pin. Applying a capacitor to RAMP spreads the switching frequency by up to 70% around the nominal value set by the RT resistor, reducing peak EMI emissions and easing compliance with CISPR-15 and other radiated emissions standards. SSFM is enabled by default and requires no external clock source - a core differentiator of the LT3795HFE#PBF in high-power LED driver applications.
LT3795HFE#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 28-TSSOP (0.173", 4.40mm Width) Exposed Pad
- Packaging:
- Tube
- Product Status:
- Active
- Type:
- DC DC Controller
- Topology:
- -
- Internal Switch(s):
- No
- Number of Outputs:
- 1
- Voltage - Supply (Min):
- 4.5V
- Voltage - Supply (Max):
- 110V
- Voltage - Output:
- -
- Current - Output / Channel:
- -
- Frequency:
- 100kHz ~ 1MHz
- Dimming:
- Analog, PWM
- Applications:
- -
- Operating Temperature:
- -40°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 28-TSSOP-EP
LT3795HFE#PBF FAQ
1.How can I place an order for LT3795HFE#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3795HFE#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 LT3795HFE#PBF reliable?
The price and inventory of LT3795HFE#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3795HFE#PBF is usually 5 days.
3.What payment methods are accepted for LT3795HFE#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3795HFE#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3795HFE#PBF?
LT3795HFE#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3795HFE#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 LT3795HFE#PBF?
For technical support, including LT3795HFE#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3795HFE#PBF requirements.
6.How does Aetrix verify that LT3795HFE#PBF is sourced from the original manufacturer or authorized distributors?
All LT3795HFE#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 LT3795HFE#PBF meets industry standards.
7.What is the process for return or replacement of LT3795HFE#PBF?
All LT3795HFE#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3795HFE#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 LT3795HFE#PBF part is unused and in its original packaging.
Return procedure for LT3795HFE#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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