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Analog Devices Inc. LT3796IFE#TRPBF
- Part No.:
- LT3796IFE#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- LED Drivers
- Package:
- 28-TSSOP (0.173", 4.40mm Width) Exposed Pad
- Datasheet:
-
LT3796IFE#TRPBF.pdf
- Description:
- IC LED DRIVER CTRLR PWM 28TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:3,551
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Product details
Overview
LT3796IFE#TRPBF from Analog Devices (formerly Linear Technology) is a 100V constant-current/constant-voltage DC/DC controller optimized for high-power LED driving with dual current sense capability. It supports 6V–100V input, delivers up to 3000:1 True Color PWM™ dimming, features rail-to-rail ISP/ISN common-mode range (0–100V), programmable switching frequency (100kHz–1MHz), and integrated top-gate PMOS driver for high-side disconnect - used in automotive exterior lighting and industrial high-voltage LED arrays.
For engineers reviewing the LT3796IFE#TRPBF datasheet, LT3796IFE#TRPBF pinout, LT3796IFE#TRPBF application, or LT3796IFE#TRPBF equivalent, key selection criteria include its dual-loop regulation architecture (FB1/FB2), independent top-gate enable (TGEN), C/10 battery charging detection, open-LED protection with VMODE flag, and 28-lead TSSOP package with exposed thermal pad.
Technical Context
The LT3796IFE#TRPBF implements fixed-frequency current-mode control with two ground-referenced feedback pins (FB1, FB2) enabling simultaneous constant-voltage and constant-current regulation. Its dual current sense amplifiers support independent monitoring of LED string current (ISP/ISN) and input supply current (CSP/CSN), with rail-to-rail 0–100V common-mode range and ±3mV input offset.
It integrates a 7.7V LDO (INTVCC) with 85mA current limit, NMOS gate driver (20ns rise, 18ns fall), top-gate PMOS driver (50ns rise, 100ns fall), and programmable soft-start/fault restart timer via SS pin. The LT3796-1 variant (this part) includes TGEN pin for independent PMOS loop disable - distinct from SYNC on LT3796 - enabling dual-string or extended analog dimming configurations.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 6V to 100V - supports wide-range industrial and automotive inputs including 48V systems and transient-tolerant 85V LED strings. |
| Switching Frequency | 100kHz to 1MHz - set by RT resistor; enables optimization of efficiency vs. size for high-power LED drivers. |
| Current Sense Threshold | 100mV to 125mV (SENSE pin) - precise overcurrent protection with 113mV typical limit, independent of load voltage. |
| FB1/FB2 Regulation Voltage | 1.238V (typical) - tight 1.230V–1.270V tolerance enables accurate CV regulation and open-LED fault detection. |
| VREF Output | 2.015V (typical) - stable internal reference for CTRL biasing and analog dimming scaling. |
| Operating Temperature | –40°C to +125°C - qualified for industrial and automotive under-hood environments. |
| Package | 28-Lead TSSOP with exposed pad - thermally enhanced for >4W dissipation in compact LED driver PCBs. |
Pinout & Package
LT3796IFE#TRPBF is housed in a 28-lead plastic TSSOP (FE package) with exposed thermal pad (Pin 29 = GND). The package requires soldering of the exposed pad to PCB ground plane for thermal and electrical integrity.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| ISP (1) | Positive current sense input / TG driver rail | Connects to LED string anode; supplies power to top-gate driver; supports 0–100V common-mode operation. |
| ISN (2) | Negative current sense input | Kelvin connection to current-sense resistor low side; enables accurate LED current regulation independent of ground noise. |
| TG (3) | Top-gate PMOS driver output | Drives external high-side PMOS switch; clamped to VISP – 7V for safe gate drive; inverted PWM logic. |
| GND (4,17,21,22,29) | Power and signal ground | Multiple ground pins reduce impedance; exposed pad (29) must be soldered to PCB ground plane for thermal management. |
| ISMON (5) | Current monitor reporting output | Sources ILED × RLED × 4 - provides isolated analog current readback without shunt resistor duplication. |
| FB2 (6) | Secondary voltage feedback input | Regulates auxiliary voltage rail to 1.25V; triggers TG high and GATE low if driven above 1.3V for overvoltage shutdown. |
| FB1 (7) | Primary voltage feedback / open-LED detect | Enables CV mode or open-circuit detection; asserts VMODE when V(ISP−ISN) < 25mV and FB1 > 1.19V. |
| VC (8) | Error amplifier output | High-impedance during PWM low; stores demand state for seamless dimming transitions; requires RC compensation. |
| CTRL (9) | Current threshold programming | Sets V(ISP−ISN) threshold from 16mV to 250mV via 0.2V–1.2V input; enables linear analog dimming and temperature compensation. |
| VREF (10) | 2.015V reference output | Stable reference for CTRL biasing; capable of sourcing 100µA for external resistor dividers. |
| SS (11) | Soft-start / fault timer | 28µA pull-up to 2.5V sets soft-start time; switches to 2.8µA pull-down during faults to implement restart delay. |
| RT (12) | Frequency programming | Resistor to GND sets oscillator frequency; 82.5k yields 250kHz, 19.6k yields 400kHz, 6.65k yields 1MHz. |
| TGEN (13) | Top-gate enable (LT3796-1 only) | Low signal forces TG high to disable PMOS loop independently of PWM - enables dual-string or extended dimming range. |
| PWM (14) | Digital dimming input | Active-low PWM disables switching, idles oscillator, pulls TG high, and places VC in hold mode for flicker-free dimming. |
| FAULT (15) | Open-collector fault flag | Pulled low on FB1 overvoltage, INTVCC UVLO, LED overcurrent (>375mV), or thermal shutdown; latched during PWM low. |
| VMODE (16) | Open-LED status flag | Open-collector output pulled low when FB1 > 1.19V and V(ISP−ISN) < 25mV - signals open-circuit condition with hysteresis. |
| SENSE (18) | Switch current sense input | Kelvin-connected to high-side of RSENSE; monitors MOSFET conduction current for peak-current-mode control. |
| GATE (19) | NMOS gate driver output | Swings between INTVCC and GND; drives external N-channel MOSFET; pulled low during fault/idle for safety. |
| INTVCC (20) | Internal LDO output | 7.7V regulated supply for gate drivers and internal circuitry; requires 4.7µF local bypass; can be tied to VIN if VIN ≤ 7V. |
| VIN (23) | Main input supply | Accepts 6V–100V; requires ≥0.22µF local ceramic bypass; withstands 100V transients per Absolute Maximum Ratings. |
| EN/UVLO (24) | Enable and undervoltage lockout | 1.22V falling threshold with user-programmable hysteresis; sub-µA quiescent current when disabled. |
| VS (25) | Current sense amplifier supply | 3V–100V supply for ISP/ISN amplifier; enables high-side current sensing without level-shifting components. |
| CSN (26) | Current sense amplifier negative input | Paired with CSP; supports 0–100V common-mode; typically tied to VS for input current monitoring. |
| CSP (27) | Current sense amplifier positive input | Connected to VIN via RIN1; generates CSOUT = (VISP−VISN)/RIN1 for input current reporting. |
| CSOUT (28) | Current sense amplifier output | Sources current proportional to input current; used with external resistor to generate analog monitor voltage. |
Key Features
| Feature | Design Value |
|---|---|
| Dual current sense architecture | Independent ISP/ISN (LED current) and CSP/CSN (input current) paths with rail-to-rail 0–100V common-mode range enable system-level power monitoring and fault isolation. |
| True Color PWM™ dimming | 3000:1 dimming ratio achieved via synchronized PWM input and high-speed gate drivers - preserves LED color consistency across full brightness range. |
| Programmable open-LED protection | VMODE flag asserts with configurable hysteresis when V(ISP−ISN) drops below 25mV while FB1 remains active - prevents thermal runaway in failed-string conditions. |
| C/10 battery charging detection | Integrated comparator triggers at V(ISP−ISN) = 25mV when FB1 = 1.25V - enables accurate end-of-charge detection for Li-ion and supercapacitor systems. |
| Independent top-gate enable (TGEN) | TGEN pin allows hardware-level disable of PMOS disconnect loop without affecting PWM timing - critical for dual-string LED architectures and analog dimming extension. |
| Thermal fault management | Integrated thermal shutdown with automatic restart via SS pin discharge - eliminates need for external thermal sensors in compact LED driver designs. |
Applications
| Automotive Exterior Lighting | Industrial High-Voltage LED Arrays |
|---|---|
|
Use Scenario: Driving 85V LED strings in headlamps and fog lamps with adaptive beam control. IC Role / Device Role / Timing Role: Constant-current controller regulating LED current up to 4A while synchronizing PWM dimming with vehicle CAN bus commands. Use Value: Enables 3000:1 True Color PWM™ dimming without color shift, supports 100V transient immunity, and provides VMODE-fault signaling for ASIL-B functional safety compliance. |
Use Scenario: Powering 48V–72V industrial LED fixtures in factory automation and warehouse lighting. IC Role / Device Role / Timing Role: Dual-loop regulator maintaining constant current for LEDs while monitoring input current for predictive maintenance and energy metering. Use Value: CSP/CSN current sense amplifier delivers real-time input power data; TGEN pin enables staged startup of multi-string arrays to limit inrush. |
| Battery & Supercapacitor Chargers | Accurate Current-Limited Voltage Regulators |
|
Use Scenario: Charging 24V LiFePO₄ battery packs and 48V supercapacitor banks in renewable energy storage systems. IC Role / Device Role / Timing Role: C/10 detection comparator and programmable current limit enforce precise constant-current/constant-voltage charge profiles. Use Value: Eliminates need for external op-amps and comparators; 25mV C/10 threshold ensures ±1% charge termination accuracy across temperature. |
Use Scenario: Providing stable 12V/3A regulated output for sensitive instrumentation in test equipment. IC Role / Device Role / Timing Role: Constant-voltage regulator using FB2 feedback with 1.238V reference and 100ppm/°C drift - configured as precision linear post-regulator. Use Value: 1.230V–1.270V FB2 tolerance and 1.5m%/V line regulation ensure <±0.5% output variation across 6V–100V input range. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar constant-current/constant-voltage controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3789EUF#TRPBF | Single-loop synchronous buck-boost controller; no ISP/ISN dual sense; lacks TGEN and VMODE; 40V max input. | Targeted at lower-voltage battery-powered LED systems; no high-side PMOS driver or open-LED flag. | Select when input voltage stays below 40V and dual-string or fault-flagging is unnecessary. |
| LT3965EFE#TRPBF | 8-channel LED driver with integrated MOSFETs; 60V max input; fixed 200kHz–2MHz frequency; no CSP/CSN input monitoring. | Designed for multi-zone architectural lighting; not suitable for >60V or high-power single-string applications. | Choose for distributed multi-string control where board space is constrained and discrete FETs are undesirable. |
Compared with LTC3789EUF#TRPBF and LT3965EFE#TRPBF, the LT3796IFE#TRPBF uniquely combines 100V operation, dual current sense (LED + input), TGEN-controlled loop disable, and VMODE open-LED signaling - making it the only option for high-reliability, high-voltage LED drivers requiring system-level diagnostics and staged power delivery.
Availability
LT3796IFE#TRPBF is available at Aetrix Electronics and suitable for automotive lighting, industrial LED arrays, and battery charging systems requiring stable component supply, long-term lifecycle support, and guaranteed -40°C to +125°C operation.
Supply support for LT3796IFE#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 acquired Linear Technology in 2017 and maintains full product support, datasheets, and application engineering for legacy Linear parts including the LT3796 family.
The LT3796 series was designed specifically for high-power LED drivers requiring dual-loop regulation, high-voltage robustness, and diagnostic capabilities - targeting automotive, industrial, and energy storage applications.
FAQ
What is the maximum input voltage rating for the LT3796IFE#TRPBF?
The LT3796IFE#TRPBF has an absolute maximum input voltage (VIN) rating of 100V, as specified in the Absolute Maximum Ratings table. It is designed to operate continuously from 6V to 100V input, with transient tolerance up to 100V - making it suitable for 48V and 72V industrial systems and automotive applications with load-dump protection requirements. Operation beyond 100V risks permanent damage.
Does the LT3796IFE#TRPBF support dual LED string regulation?
Yes, the LT3796IFE#TRPBF supports dual LED string regulation via its LT3796-1 architecture. The TGEN pin enables independent hardware disable of the top-gate PMOS loop, allowing one string to be deactivated while the other remains active - ideal for adaptive lighting or redundancy schemes. This functionality is absent in the base LT3796 variant and confirmed in the Pin Functions section for Pin 13 (TGEN).
How does the VMODE pin function in the LT3796IFE#TRPBF?
The VMODE pin on the LT3796IFE#TRPBF is an open-collector output that asserts low when FB1 exceeds 1.19V (typical) and V(ISP−ISN) falls below 25mV (typical), indicating an open-LED condition. It updates only during PWM high time and latches during PWM low, providing reliable fault signaling without false triggers from transient noise. An external pull-up resistor is required for proper operation.
Can the LT3796IFE#TRPBF be used for battery charging applications?
Yes, the LT3796IFE#TRPBF includes dedicated C/10 charging detection with a 25mV threshold (when FB1 = 1.25V), enabling precise end-of-charge detection for lithium-based batteries and supercapacitors. Its constant-current/constant-voltage regulation, programmable current limit, and thermal fault management make it suitable for 24V–48V battery charger designs requiring high accuracy and reliability.
What is the purpose of the TGEN pin on the LT3796IFE#TRPBF?
The TGEN pin is exclusive to the LT3796-1 variant (including LT3796IFE#TRPBF) and provides independent hardware control of the top-gate PMOS driver. When pulled low, TGEN forces TG high to disable the PMOS loop regardless of PWM state - enabling dual-string sequencing, analog dimming extension, or fault-isolation modes not possible with PWM-only control. It is not present on the LT3796 (SYNC version).
LT3796IFE#TRPBF 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:
- Tape & Reel (TR)
- Product Status:
- Active
- Type:
- DC DC Controller
- Topology:
- SEPIC, Step-Down (Buck), Step-Up (Boost)
- Internal Switch(s):
- No
- Number of Outputs:
- 1
- Voltage - Supply (Min):
- 6V
- Voltage - Supply (Max):
- 100V
- Voltage - Output:
- -
- Current - Output / Channel:
- -
- Frequency:
- 100kHz ~ 1MHz
- Dimming:
- Analog, PWM
- Applications:
- -
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 28-TSSOP-EP
LT3796IFE#TRPBF FAQ
1.How can I place an order for LT3796IFE#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3796IFE#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 LT3796IFE#TRPBF reliable?
The price and inventory of LT3796IFE#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3796IFE#TRPBF is usually 5 days.
3.What payment methods are accepted for LT3796IFE#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3796IFE#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3796IFE#TRPBF?
LT3796IFE#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3796IFE#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 LT3796IFE#TRPBF?
For technical support, including LT3796IFE#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3796IFE#TRPBF requirements.
6.How does Aetrix verify that LT3796IFE#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT3796IFE#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 LT3796IFE#TRPBF meets industry standards.
7.What is the process for return or replacement of LT3796IFE#TRPBF?
All LT3796IFE#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3796IFE#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 LT3796IFE#TRPBF part is unused and in its original packaging.
Return procedure for LT3796IFE#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LT3796IFE#TRPBF Tags
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