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Analog Devices Inc. LT3796IFE-1#TRPBF
- Part No.:
- LT3796IFE-1#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- LED Drivers
- Package:
- 28-TSSOP (0.173", 4.40mm Width) Exposed Pad
- Datasheet:
-
LT3796IFE-1#TRPBF.pdf
- Description:
- IC LED DRIVER CTRLR PWM 28TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:1,286
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Product details
Overview
LT3796IFE-1#TRPBF from Analog Devices (formerly Linear Technology) is a 100V constant-current/constant-voltage DC/DC controller optimized for dual-string LED driving and high-voltage battery/supercapacitor charging. It features dual current sense amplifiers (ISP/ISN and CSP/CSN), programmable full-scale current threshold (250 mV), 100 kHz–1 MHz adjustable switching frequency, and independent top-gate enable (TGEN) for PMOS control. It operates in boost, buck-boost, or SEPIC topologies with true-color PWM dimming up to 3000:1.
For engineers reviewing the LT3796IFE-1#TRPBF datasheet, LT3796IFE-1#TRPBF pinout, LT3796IFE-1#TRPBF application, or LT3796IFE-1#TRPBF equivalent, key selection considerations include its dual-loop current regulation capability, 28-lead TSSOP package with exposed thermal pad, –40°C to +125°C industrial temperature grade, rail-to-rail ISP/ISN common-mode range (0 V to 100 V), and dedicated TGEN pin for second-string loop enable/disable - distinct from the LT3796 variant's SYNC function.
Technical Context
The LT3796IFE-1#TRPBF implements a fixed-frequency, current-mode control architecture with two independent transconductance error amplifiers (FB1/FB2) regulating to 1.25 V, enabling simultaneous constant-voltage and constant-current operation. Its dual current sensing paths support primary LED string regulation via ISP/ISN and secondary monitoring or auxiliary regulation via CSP/CSN, with CSOUT reporting scaled current (×4) for system telemetry.
It integrates a high-side PMOS driver (TG) with internal 7 V gate clamp and a low-side NMOS gate driver (GATE), both synchronized to an oscillator whose frequency is set by RT (85–1150 kHz). The TGEN pin (Pin 13) provides direct, PWM-independent control of the TG output - a defining feature distinguishing the LT3796-1 family from LT3796 - enabling dynamic deactivation of a second current loop without affecting main converter operation.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 6 V to 100 V - supports wide-range industrial and automotive input rails, including transient-tolerant 85 V LED strings. |
| Switching Frequency | 100 kHz to 1 MHz - adjustable via RT resistor; enables optimization of efficiency, EMI, and magnetics size. |
| Current Sense Threshold | 250 mV full-scale (typical) - sets precise LED current with linear CTRL pin scaling (0.25 × VCTRL + offset). |
| ISP/ISN Common-Mode Range | 0 V to 100 V - allows high-side or low-side current sensing in high-voltage LED strings without level-shifting. |
| Operating Temperature | –40°C to +125°C - qualified for industrial and harsh-environment applications requiring extended thermal reliability. |
| PWM Dimming Ratio | Up to 3000:1 - enables high-fidelity color-matching in architectural and display lighting without flicker. |
| Package | 28-Lead TSSOP with exposed pad - provides enhanced thermal dissipation for high-power LED driver designs. |
Pinout & Package
LT3796IFE-1#TRPBF is housed in a 28-lead plastic TSSOP (FE package) with exposed thermal pad (Pin 29), which must be soldered to PCB ground for thermal and electrical integrity. Pin functions are validated per Linear Technology Document 3796fb Rev. D.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| ISP (1) | Positive current sense input / TG driver rail | Serves as high-side reference for primary LED current sensing and supplies voltage to TG driver; supports up to 100 V common-mode. |
| ISN (2) | Negative current sense input | Completes primary current sense path with ISP; Kelvin-connected to RLED negative terminal for accurate regulation. |
| TG (3) | Top-gate PMOS driver output | Drives external high-side PMOS switch; clamped to ISP − 7 V to protect gate oxide; controlled by TGEN or PWM. |
| GND (4,17,21,22,29) | Ground reference / thermal pad | Multiple GND pins provide low-impedance return paths; exposed pad (29) is mandatory for thermal management. |
| ISMON (5) | Primary current monitor output | Reports ILED × RLED × 4 as analog voltage; used for system-level current telemetry or closed-loop feedback. |
| FB2 (6) | Secondary voltage feedback input | Regulates to 1.25 V; on LT3796-1, enables overvoltage protection by pulling TG high and GATE low if driven above 1.3 V. |
| FB1 (7) | Primary voltage feedback / open-LED detection | Regulates to 1.25 V nominal; asserts VMODE flag when V(ISP−ISN) < 25 mV and FB1 > 1.19 V, signaling open-circuit fault. |
| TGEN (13) | Top-gate enable input (LT3796-1 only) | Low signal forces TG high to disable PMOS independently of PWM; enables selective deactivation of second current loop. |
| PWM (14) | Digital dimming control input | High = active regulation; low = shutdown with VC hold, TG high, GATE low - preserves state for seamless restart. |
| FAULT (15) | Open-collector fault indicator | Pulled low on FB1 overvoltage, INTVCC undervoltage, LED overcurrent (>375 mV), or thermal shutdown. |
Key Features
| Feature | Design Value |
|---|---|
| Dual independent current sense paths | ISP/ISN for primary LED regulation + CSP/CSN for secondary current/voltage monitoring or C/10 battery charging detection. |
| True-color PWM dimming (3000:1) | Preserves LED spectral consistency across dimming range by avoiding low-frequency current modulation artifacts. |
| Programmable current threshold via CTRL pin | Linear 0.25 × VCTRL scaling (0.1–1.0 V) plus offset enables analog dimming and temperature-compensated current setting. |
| Independent TGEN control for second loop | Enables dynamic activation/deactivation of a second LED string or auxiliary regulation path without disrupting main converter timing. |
| Rail-to-rail ISP/ISN common-mode range (0–100 V) | Eliminates need for external level shifters in high-voltage LED arrays, simplifying layout and improving noise immunity. |
| Integrated 7.7 V LDO (INTVCC) | Self-powered gate drivers and internal circuitry reduce external supply complexity; supports VIN ≥ 6 V operation. |
Applications
| High-Power Architectural LED Lighting | Dual-String Automotive Headlamp Control |
|---|---|
|
Use Scenario: Driving multiple high-brightness LED strings in commercial façade lighting with strict thermal and dimming fidelity requirements. IC Role / Device Role / Timing Role: Constant-current controller managing two independent LED strings via ISP/ISN and TGEN-enabled secondary loop, with 3000:1 PWM dimming synchronized to building automation signals. Use Value: Enables precise lumen matching between strings and eliminates color shift during dimming-critical for premium architectural installations. |
Use Scenario: Controlling low-beam and high-beam LED arrays in adaptive front-lighting systems (AFS), requiring independent current regulation and fast fault response. IC Role / Device Role / Timing Role: Dual-loop regulator using ISP/ISN for low-beam and CSP/CSN + TGEN for high-beam enable/disable, with VMODE/FAULT flags feeding vehicle CAN diagnostics. Use Value: Provides fail-safe open-LED detection and independent string control-meeting ISO 13849 PLd functional safety requirements for headlamp systems. |
| Industrial Battery & Supercapacitor Chargers | High-Voltage Industrial Power Supplies |
|
Use Scenario: Charging 48 V lithium-iron-phosphate batteries or 60 V supercapacitor banks from unregulated 6–100 V DC sources in energy storage systems. IC Role / Device Role / Timing Role: Constant-current/constant-voltage regulator using FB1 for voltage regulation and ISP/ISN for C/10 termination detection at 25 mV threshold. Use Value: Delivers accurate CC/CV transition and end-of-charge detection without external comparators-reducing BOM count and calibration overhead. |
Use Scenario: Providing stable 24 V or 48 V outputs from variable industrial DC bus (e.g., traction power, telecom rectifiers) with stringent load regulation and fault logging. IC Role / Device Role / Timing Role: High-input-voltage buck-boost controller using FB2 for CV regulation and ISMON for real-time output current telemetry. Use Value: Maintains ±1% output voltage regulation across 6–100 V input while reporting load current digitally via CSOUT-enabling predictive maintenance. |
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 |
|---|---|---|---|
| LTC3789EFE#TRPBF | Single-loop synchronous buck-boost controller; no ISP/ISN dual-sense, no TGEN, no 100 V rating (max 38 V VIN). | Targeted at lower-voltage portable power and USB PD applications; lacks LED-specific protections (VMODE, open-LED detection). | Select LTC3789EFE#TRPBF only for compact, high-efficiency 12–24 V systems where dual-string control and 100 V tolerance are unnecessary. |
| LT3762EFE#TRPBF | 100 V boost/buck-boost LED controller with single ISP/ISN sense; no CSP/CSN path, no TGEN, no C/10 detection. | Optimized for single-string high-brightness LED drivers; lacks secondary regulation capability and battery charging features. | Choose LT3762EFE#TRPBF for cost-sensitive, single-string LED applications where dual-loop flexibility and charger functionality are not required. |
Compared with LTC3789EFE#TRPBF and LT3762EFE#TRPBF, the LT3796IFE-1#TRPBF uniquely delivers dual independent current regulation loops, 100 V input tolerance, and integrated battery charging features - making it the only option among the three suitable for high-reliability dual-string LED systems with auxiliary power management.
Availability
LT3796IFE-1#TRPBF is available at Aetrix Electronics and suitable for high-power LED lighting, automotive adaptive lighting, and industrial battery charging applications requiring stable component supply, long-term lifecycle support, and guaranteed industrial temperature performance.
Supply support for LT3796IFE-1#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, Inc. (acquired Linear Technology in 2017) is a global leader in high-performance analog, mixed-signal, and power management semiconductors, serving industrial, automotive, communications, and healthcare markets.
The LT3796IFE-1#TRPBF belongs to Linear Technology's LED driver and high-voltage DC/DC controller product line, designed specifically for precision constant-current regulation in demanding lighting and power conversion applications where reliability, dimming fidelity, and multi-string flexibility are critical.
FAQ
What is the key functional difference between LT3796IFE-1#TRPBF and LT3796IFE#TRPBF?
The LT3796IFE-1#TRPBF features a TGEN (Top Gate Enable) pin (Pin 13) that provides independent, PWM-free control of the TG output to enable or disable a second current regulation loop - such as a second LED string or auxiliary charging path. In contrast, the LT3796IFE#TRPBF uses Pin 13 as SYNC for oscillator synchronization and lacks this dedicated loop-control capability. This makes LT3796IFE-1#TRPBF essential for dual-string or hybrid LED+charger architectures requiring asynchronous loop management.
Does LT3796IFE-1#TRPBF support open-LED fault detection, and how is it implemented?
Yes, LT3796IFE-1#TRPBF implements open-LED detection via the VMODE flag. When FB1 is regulating and the voltage across ISP–ISN drops below 25 mV (indicating no current flow), and FB1 exceeds 1.19 V, the VMODE pin is pulled low. This flag is updated only during PWM high time and latched during PWM low time, providing robust fault signaling compatible with microcontroller GPIO polling. The LT3796IFE-1#TRPBF also supports programmable thresholds via FB1 overvoltage (1.3 V) and C/10 detection (25 mV) for battery charging applications.
What is the maximum allowable voltage on the ISP and ISN pins of LT3796IFE-1#TRPBF?
The absolute maximum rating for both ISP and ISN pins is 100 V, with a guaranteed rail-to-rail common-mode input range of 0 V to 100 V across the full operating temperature range. This allows direct high-side current sensing in 85 V LED strings or 48 V battery systems without external level-shifting circuitry. The device maintains accuracy and stability even at 100 V common-mode, as confirmed by Electrical Characteristics Table entries for ISP/ISN input bias current and offset voltage under VS = 48 V and 0 V conditions.
Can LT3796IFE-1#TRPBF be used in buck-boost or SEPIC topologies, or is it limited to boost-only operation?
LT3796IFE-1#TRPBF is topology-flexible and supports boost, buck-boost, SEPIC, and flyback configurations - confirmed by its current-mode architecture, separate SENSE and ISP/ISN inputs, and dual feedback (FB1/FB2) capability. The datasheet Typical Applications section shows verified SEPIC and buck-boost implementations. Its ability to regulate based on either switch current (SENSE) or load current (ISP/ISN) enables stable operation across discontinuous and continuous conduction modes in non-boost topologies - unlike fixed-topology LED drivers.
What thermal management requirements apply to the LT3796IFE-1#TRPBF package?
The LT3796IFE-1#TRPBF uses a 28-lead TSSOP with exposed thermal pad (Pin 29), which must be soldered directly to a PCB ground plane to achieve θJC = 10°C/W and maintain junction temperature ≤125°C under full load. The datasheet specifies TJMAX = 150°C but guarantees performance only to +125°C for the I-grade part. Layout best practices include using ≥4 thermal vias under the pad, connecting all GND pins (4, 17, 21, 22, 29) to the same low-impedance plane, and avoiding copper isolation around the pad - failure to follow these reduces thermal margin by >25°C in typical 5 W LED driver designs.
LT3796IFE-1#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-1#TRPBF FAQ
1.How can I place an order for LT3796IFE-1#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3796IFE-1#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-1#TRPBF reliable?
The price and inventory of LT3796IFE-1#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-1#TRPBF is usually 5 days.
3.What payment methods are accepted for LT3796IFE-1#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3796IFE-1#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3796IFE-1#TRPBF?
LT3796IFE-1#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3796IFE-1#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-1#TRPBF?
For technical support, including LT3796IFE-1#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3796IFE-1#TRPBF requirements.
6.How does Aetrix verify that LT3796IFE-1#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT3796IFE-1#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-1#TRPBF meets industry standards.
7.What is the process for return or replacement of LT3796IFE-1#TRPBF?
All LT3796IFE-1#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3796IFE-1#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-1#TRPBF part is unused and in its original packaging.
Return procedure for LT3796IFE-1#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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