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Analog Devices Inc. LT3796EFE#TRPBF
- Part No.:
- LT3796EFE#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- LED Drivers
- Package:
- 28-TSSOP (0.173", 4.40mm Width) Exposed Pad
- Datasheet:
-
LT3796EFE#TRPBF.pdf
- Description:
- IC LED DRIVER CTRLR PWM 28TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:3,061
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Product details
Overview
LT3796EFE#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 high-side PMOS gate driver for LED string disconnect - used in industrial LED lighting systems requiring precise current regulation and fault robustness.
For engineers reviewing the LT3796EFE#TRPBF datasheet, LT3796EFE#TRPBF pinout, LT3796EFE#TRPBF application, or LT3796EFE#TRPBF equivalent, key selection criteria include its dual-loop current sensing architecture, VMODE/FAULT open-LED detection logic, C/10 battery charging compatibility, 28-lead TSSOP thermal performance, and independent top-gate enable (TGEN) functionality specific to the LT3796-1 variant family.
Technical Context
The LT3796EFE#TRPBF implements fixed-frequency current-mode control with two ground-referenced FB pins enabling simultaneous constant-voltage regulation (via FB1/FB2) and LED protection. Its dual current sense amplifiers support independent regulation of primary LED current (ISP/ISN) and secondary current/voltage (CSP/CSN), with rail-to-rail input common-mode range up to 100V and programmable full-scale threshold (250mV typical at CTRL = 2V).
It integrates a 7.7V LDO (INTVCC) with 85mA current limit, NMOS GATE driver (20ns rise/18ns fall), and high-side PMOS TG driver (50ns rise/100ns fall) with internal 7V VGS clamp. The device uses a 28-lead TSSOP package with exposed pad (Pin 29) soldered to PCB ground for thermal management and EMI reduction.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 6V to 100V - supports wide-range industrial and automotive inputs including transient surges up to 100V. |
| Switching Frequency | 100kHz to 1MHz - adjustable via RT resistor; enables optimization of efficiency vs. size in high-power LED drivers. |
| Current Sense Threshold | 250mV (full-scale, CTRL = 2V) - sets precise LED current with ±3% tolerance over temperature. |
| FB Regulation Voltage | 1.25V (FB1/FB2) - enables accurate constant-voltage regulation for battery charging or auxiliary rails. |
| VMODE Open-LED Threshold | VFB1 – 60mV (typical) - latches open-circuit fault when ISP–ISN voltage drops below 25mV while FB1 > 1.19V. |
| INTVCC Output | 7.7V @ 85mA - powers internal circuitry and external gate drivers without auxiliary supply. |
| Operating Temperature | –40°C to +125°C - qualified for industrial ambient environments with derating above 125°C junction. |
Pinout & Package
LT3796EFE#TRPBF is housed in a 28-lead plastic TSSOP package (FE) with exposed thermal pad (Pin 29) that must be soldered to PCB ground. Pin count, layout, and thermal design comply with JEDEC MO-153.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| ISP (1) | Positive current sense input / TG driver rail | Serves as high-side reference for LED current sensing and supplies power to TG driver; operates up to 100V. |
| ISN (2) | Negative current sense input | Completes ISP–ISN differential pair; Kelvin-connected to RLED low-side terminal for accurate current measurement. |
| TG (3) | Top-gate PMOS driver output | Drives external high-side PMOS disconnect switch; includes internal 7V VGS clamp for safe MOSFET biasing. |
| GND (4,17,21,22,29) | Ground reference / thermal pad | Multiple ground pins reduce impedance; exposed pad (29) must be soldered to PCB ground plane for thermal dissipation. |
| ISMON (5) | Current report output | Provides analog ILED × RLED × 4 signal for monitoring or closed-loop feedback; sinks to GND during PWM low. |
| FB2 (6) | Secondary voltage loop input | Regulates second output (e.g., auxiliary rail or second LED string); asserts TG high if driven >1.3V for overvoltage shutdown. |
| FB1 (7) | Primary voltage loop / open-LED detect | Enables CV mode or open-LED protection; triggers VMODE flag when VFB1 > 1.19V and VISP–ISN < 25mV. |
| VC (8) | Error amplifier output | Integrates error between sensed current and target; high-impedance during PWM low to retain state across dimming cycles. |
| CTRL (9) | Current threshold programming | Linearly scales full-scale sense threshold from 25mV (0.2V) to 250mV (2V); default 250mV when tied to VREF. |
| VREF (10) | 2.015V precision reference | Stable 2.015V output with ±15mV accuracy; drives CTRL divider or external circuits with ≤100µA load. |
| SS (11) | Soft-start / fault timer | 28µA pull-up charges external capacitor; 2.8µA pull-down discharges on fault (overcurrent, UVLO, thermal) to latch shutdown. |
| RT (12) | Frequency programming | Resistor-to-GND sets oscillator frequency; 82.5k yields ~105kHz, 19.6k yields ~400kHz, 6.65k yields ~1MHz. |
| TGEN (13) | Top-gate enable (LT3796-1 only) | Independent control of TG driver; low disables PMOS regardless of PWM state - enables dual-string sequencing. |
| PWM (14) | Digital dimming input | Active-low signal disables switching, idles oscillator, pulls TG high, and places VC in hold mode for seamless dimming. |
| FAULT (15) | Open-collector fault flag | Pulled low on FB1 overvoltage (>1.3V), INTVCC UVLO (<4V), LED overcurrent (>375mV), or thermal shutdown. |
| VMODE (16) | Open-LED status flag | Open-collector output pulled low when FB1 > 1.19V and ISP–ISN < 25mV - signals open-circuit LED string condition. |
| SENSE (18) | Switch current sense input | Kelvin-connected to high-side of RSENSE; monitors N-MOSFET source current with 113mV current-limit threshold. |
| GATE (19) | N-MOSFET gate driver | Drives external low-side switch between INTVCC and GND; 20ns rise/18ns fall into 3300pF load. |
| INTVCC (20) | Internal LDO output | 7.7V regulated supply for gate drivers and logic; requires 4.7µF local ceramic bypass capacitor. |
| VIN (23) | Main input supply | Accepts 6–100V input; must be bypassed with ≥0.22µF ceramic capacitor close to pin. |
| EN/UVLO (24) | Enable / undervoltage lockout | 1.22V falling threshold with programmable hysteresis; 3µA internal pull-down enables resistor-divider hysteresis design. |
| VS (25) | Current sense amplifier supply | Power rail for CSP/CSN amplifier; operates from 3V to 100V - enables high-side current sensing without level shifters. |
| CSN (26) | Negative current sense input | Reference node for CSP amplifier; typically tied to VS and CSP in servo configuration per Figure 9. |
| CSP (27) | Positive current sense input | Sinks current proportional to VSENSE/RIN1; enables reporting of high-side current via CSOUT. |
| CSOUT (28) | Current sense amplifier output | Sources current ICSOUT = VSENSE/RIN1; used for current monitoring or secondary regulation loops. |
Key Features
| Feature | Design Value |
|---|---|
| Dual independent current sense paths | ISP/ISN for primary LED current regulation; CSP/CSN for secondary current or voltage regulation - enables dual-string or charger applications. |
| True-color PWM dimming | 3000:1 dimming ratio with no color shift - achieved via precise current regulation and fast gate drivers minimizing duty-cycle distortion. |
| Programmable open-LED protection | VMODE flag asserts when FB1 > 1.19V and ISP–ISN < 25mV; configurable hysteresis prevents false triggering during transients. |
| C/10 battery charging detection | 25mV comparator threshold (VMODE falling) enables accurate end-of-charge detection for Li-ion and supercapacitor systems. |
| High-side PMOS disconnect driver | TG pin provides controlled turn-on/turn-off of series PMOS with internal 7V VGS clamp - eliminates need for external level-shifting circuitry. |
| Adjustable frequency synchronization | SYNC pin (LT3796) or TGEN pin (LT3796-1) allows external clock alignment or independent top-gate control - critical for EMI reduction in multi-channel systems. |
Applications
| High-Power LED Street Lighting | Battery & Supercapacitor Charging |
|---|---|
Use Scenario: Outdoor LED luminaires powered from 24–72V DC distribution lines with surge immunity requirements up to 100V. IC Role / Device Role / Timing Role: Constant-current controller regulating 1–5A LED strings; uses ISP/ISN sensing and TG-driven PMOS disconnect for fail-safe open-circuit protection. Use Value: Enables >100,000-hour lifetime with 3000:1 dimming, thermal foldback, and VMODE-latched fault signaling for remote maintenance. | Use Scenario: Precision charging of 48V LiFePO₄ battery banks or 50V supercapacitor arrays in energy storage systems. IC Role / Device Role / Timing Role: Accurate current-limited voltage regulator using FB1 for CV stage and C/10 detection (25mV threshold) for charge termination. Use Value: Achieves ±1.5% current accuracy and 1.25V FB regulation enables <±1% voltage tolerance during constant-voltage phase. |
| Dual-String Architectural LED Drivers | Industrial High-Voltage LED Backlighting |
Use Scenario: Multi-zone architectural lighting with independent dimming of warm-white and cool-white LED strings. IC Role / Device Role / Timing Role: Dual-loop controller using ISP/ISN for main string and CSP/CSN + FB2 for secondary string; TGEN enables staggered enable/disable sequencing. Use Value: Eliminates separate controllers per string - reduces BOM cost by 40% and PCB area by 35% versus discrete solutions. | Use Scenario: High-brightness LCD backlights in medical imaging or industrial HMI displays requiring 80–100V LED strings. IC Role / Device Role / Timing Role: Boost-mode constant-current driver with 100V input tolerance and rail-to-rail ISP/ISN sensing up to 100V common-mode. Use Value: Supports direct connection to 96V DC bus without pre-regulator; 113mV SENSE threshold ensures stable current limiting under high dv/dt conditions. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar constant-current LED controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3783EFE#TRPBF | Single current sense path; no CSP/CSN amplifier; no TGEN pin; 60V max input; 500kHz max frequency. | Targeted at lower-voltage single-string LED drivers; lacks dual-loop capability and 100V operation. | Select when cost-sensitive designs require only basic CC/CV control below 60V with no secondary regulation need. |
| LM3410XSDX/NOPB | Monolithic 1.6A buck LED driver; integrated MOSFET; 40V max input; no ISP/ISN sensing; no TG driver. | Entry-level solution for low-power portable LED lighting; no high-side disconnect or programmable dimming. | Select for compact, low-BOM-cost applications under 40V input and <1A output where system-level protection is handled externally. |
Compared with LTC3783EFE#TRPBF and LM3410XSDX/NOPB, the LT3796EFE#TRPBF uniquely supports 100V operation, dual independent current loops, and integrated high-side PMOS control - making it the only option among the three suitable for industrial-grade, multi-string, high-voltage LED systems requiring C/10 charging and open-LED latching.
Availability
LT3796EFE#TRPBF is available at Aetrix Electronics and suitable for high-power LED lighting, battery/supercapacitor charging, and industrial backlighting applications requiring stable component supply, long-term lifecycle assurance, and traceable sourcing from authorized channels.
Supply support for LT3796EFE#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 design tools for the LT3796 family.
The LT3796 product line was designed specifically for high-reliability, high-voltage LED driver and precision current-limited power supply applications - emphasizing dual-loop sensing, robust fault handling, and thermal resilience in industrial environments.
FAQ
What is the maximum input voltage rating for the LT3796EFE#TRPBF?
The LT3796EFE#TRPBF has an absolute maximum input voltage rating of 100V on VIN, EN/UVLO, ISP, ISN, CSP, CSN, and VS pins. This allows direct operation from unregulated 48V, 72V, or 96V industrial DC buses with transient surge tolerance - critical for outdoor LED lighting and energy storage systems where input rails may experience lightning-induced spikes.
Does the LT3796EFE#TRPBF support dual independent LED string control?
Yes, the LT3796EFE#TRPBF supports dual independent current regulation: ISP/ISN controls the primary LED string, while CSP/CSN - combined with FB2 - regulates a secondary current or voltage output. The LT3796-1 variant adds TGEN for independent sequencing, enabling true dual-string architectures without external multiplexing or additional controllers.
How does open-LED protection work on the LT3796EFE#TRPBF?
Open-LED protection on the LT3796EFE#TRPBF uses VMODE flag assertion: when FB1 exceeds 1.19V (indicating regulated voltage present) and ISP–ISN drops below 25mV (indicating no current flow), the VMODE pin pulls low. This latched signal remains active until SS is discharged below 0.2V - providing reliable fault indication even during PWM dimming intervals.
Can the LT3796EFE#TRPBF be used for battery charging applications?
Yes, the LT3796EFE#TRPBF is explicitly designed for battery and supercapacitor charging. Its C/10 comparator (25mV threshold) enables precise end-of-charge detection, while FB1 regulation (1.25V) and current-sense accuracy (±3%) support constant-current/constant-voltage charging profiles for Li-ion, LiFePO₄, and supercapacitors up to 100V.
What is the purpose of the TGEN pin on the LT3796EFE#TRPBF?
The TGEN pin is exclusive to the LT3796-1 variant and provides independent control of the TG driver. When TGEN is pulled low, TG transitions high to disable the external PMOS switch - regardless of PWM state. This enables dual-string sequencing, safety interlocks, or analog dimming extension without disrupting the main PWM dimming waveform.
LT3796EFE#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
LT3796EFE#TRPBF FAQ
1.How can I place an order for LT3796EFE#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3796EFE#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 LT3796EFE#TRPBF reliable?
The price and inventory of LT3796EFE#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3796EFE#TRPBF is usually 5 days.
3.What payment methods are accepted for LT3796EFE#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3796EFE#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3796EFE#TRPBF?
LT3796EFE#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3796EFE#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 LT3796EFE#TRPBF?
For technical support, including LT3796EFE#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3796EFE#TRPBF requirements.
6.How does Aetrix verify that LT3796EFE#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT3796EFE#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 LT3796EFE#TRPBF meets industry standards.
7.What is the process for return or replacement of LT3796EFE#TRPBF?
All LT3796EFE#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3796EFE#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 LT3796EFE#TRPBF part is unused and in its original packaging.
Return procedure for LT3796EFE#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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