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Analog Devices Inc. LT3796EFE-1#PBF
- Part No.:
- LT3796EFE-1#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- LED Drivers
- Package:
- 28-TSSOP (0.173", 4.40mm Width) Exposed Pad
- Datasheet:
-
LT3796EFE-1#PBF.pdf
- Description:
- IC LED DRIVER CTRLR PWM 28TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:1,254
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Product details
Overview
LT3796EFE-1#PBF 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 charging. It features dual current sense amplifiers, programmable analog dimming via CTRL pin (250 mV full-scale threshold), 3000:1 true-color PWM dimming, and independent top-gate enable (TGEN) for PMOS-based second-loop control. It operates from 6V to 100V input and supports boost, SEPIC, and flyback topologies in industrial LED lighting systems.
For engineers reviewing the LT3796EFE-1#PBF datasheet, LT3796EFE-1#PBF pinout, LT3796EFE-1#PBF application, or LT3796EFE-1#PBF equivalent, key selection criteria include its dual-current-sense architecture with rail-to-rail common-mode range (0–100 V), TGEN-controlled second regulation loop, 100 kHz–1 MHz adjustable switching frequency, and integrated high-side PMOS driver with 7 V gate clamp - all in a 28-lead TSSOP package rated for –40°C to 125°C.
Technical Context
The LT3796EFE-1#PBF implements fixed-frequency current-mode control with two independent transconductance error amplifiers (FB1/FB2), each regulating to 1.25 V. Its ISP/ISN current sense amplifier supports up to 100 V common-mode voltage and provides linearly programmable thresholds (16–257 mV) via CTRL pin voltage (0.2–1.2 V). The dedicated TGEN pin enables asynchronous activation/deactivation of the top-gate driver without affecting PWM timing or oscillator state.
Unlike the LT3796, the LT3796-1 variant replaces SYNC functionality with TGEN and adds independent top-gate enable logic - allowing selective disable of one LED string or extension of analog dimming range using an external PMOS switch. The device integrates a 7.7 V LDO (INTVCC), rail-to-rail SENSE comparator with 113 mV typical current limit, and open-collector VMODE/FAULT flags synchronized to PWM high periods.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 6 V to 100 V - supports wide-range industrial and automotive LED power supplies and high-voltage battery chargers. |
| Switching Frequency | 100 kHz to 1 MHz - adjustable via RT resistor; enables optimization of efficiency, size, and EMI in high-power LED drivers. |
| Current Sense Threshold | Programmable 16–257 mV via CTRL pin - enables precise analog dimming and C/10 battery charge termination detection. |
| ISP/ISN Common-Mode Range | 0 V to 100 V - allows direct high-side current sensing in boost/flyback configurations without level-shifting circuitry. |
| Top-Gate Driver Enable | TGEN pin (Pin 13) - independently controls PMOS disconnect switch for dual-string operation or extended dimming range. |
| Operating Temperature | –40°C to +125°C - qualified for industrial and outdoor LED lighting environments with thermal derating above 125°C. |
| Package | 28-Lead TSSOP with exposed pad - thermally enhanced for high-power dissipation; requires soldered GND pad for thermal and electrical integrity. |
Pinout & Package
LT3796EFE-1#PBF is housed in a 28-lead plastic TSSOP (FE package) with exposed thermal pad (Pin 29 = GND). The package measures 9.7 mm × 4.4 mm × 1.1 mm and requires PCB-level thermal management via soldered exposed pad.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| ISP (1) | Positive current sense input / TG driver supply rail | Serves as high-side reference for LED current sensing and powers TG driver; supports 0–100 V common-mode operation. |
| ISN (2) | Negative current sense input | Completes ISP/ISN differential pair; Kelvin-connected to current-sense resistor low side for accurate high-voltage sensing. |
| TG (3) | Top-gate driver output | Drives external PMOS switch between ISP and (ISP – 7 V); internal 7 V clamp prevents gate overvoltage. |
| GND (4,17,21,22,29) | Ground reference / current sense return | Multiple GND pins provide low-impedance return path for sense resistors and power stages; exposed pad must be soldered. |
| ISMON (5) | Current monitor output | Reports scaled LED current (VISMON = ILED × RLED × 4); used for system telemetry or closed-loop monitoring. |
| FB2 (6) | Voltage feedback 2 input | Regulates secondary loop to 1.25 V; on LT3796-1, not used for TG override (unlike LT3796). |
| FB1 (7) | Voltage feedback 1 input | Enables CV regulation or open-LED protection; asserts VMODE if V(ISP-ISN) < 25 mV and FB1 > 1.19 V. |
| VC (8) | Error amplifier output | Integrates difference between sensed current and target; high-impedance during PWM low for state retention. |
| CTRL (9) | Analog dimming threshold control | Linearly sets current sense threshold (0.25 × VCTRL + offset) from 16 mV to 250 mV; default 250 mV when tied to VREF. |
| VREF (10) | 2.015 V reference output | Stable reference for CTRL divider; supplies ≤100 µA; used for temperature compensation or dimming interface. |
| SS (11) | Soft-start / fault timer | 28 µA pull-up charges external capacitor; pulled down at 2.8 µA during faults (overcurrent, UVLO, thermal) to latch shutdown. |
| RT (12) | Frequency programming | Resistor to GND sets switching frequency; 82.5 kΩ yields ~250 kHz; supports synchronization-free design. |
| TGEN (13) | Top-gate enable input | Low signal forces TG high to disable PMOS string independently of PWM; internal 90 kΩ pull-down to GND. |
| PWM (14) | Digital dimming input | Active-low PWM enables 3000:1 dimming; disables oscillator and places GATE/TG in safe state when low. |
| FAULT (15) | Open-collector fault flag | Pulled low on FB1 overvoltage (>1.3 V), INTVCC UVLO (<4 V), LED overcurrent (>375 mV), or thermal shutdown. |
| VMODE (16) | Open-collector mode flag | Pulled low when FB1 > 1.19 V and V(ISP-ISN) < 25 mV - indicates open-LED or undervoltage condition. |
| SENSE (18) | Switch current sense input | Kelvin-connected to high-side of RSENSE; compares against 113 mV (typ) limit to prevent MOSFET overcurrent. |
| GATE (19) | NMOS gate driver output | Drives external N-channel MOSFET gate between INTVCC and GND; pulled low during fault/idle states. |
| INTVCC (20) | Internal LDO output | 7.7 V regulated supply for gate drivers and internal circuits; bypassed with ≥4.7 µF ceramic capacitor. |
| VIN (23) | Main input supply | Accepts 6–100 V; local 0.22 µF+ bypass required; powers INTVCC LDO and high-voltage bias networks. |
| EN/UVLO (24) | Enable / undervoltage lockout | 1.22 V falling threshold with programmable hysteresis; pulls 3 µA below threshold to set hysteresis with external divider. |
| VS (25) | Current sense amplifier supply | 3–100 V supply for ISP/ISN amplifier; decoupled internally; enables high-side sensing without auxiliary supply. |
| CSN (26) | Current sense negative input | Reference terminal for CSP amplifier; typically tied to VS and GND for single-ended configuration per Figure 9. |
| CSP (27) | Current sense positive input | Sinks current proportional to V(ISP-ISN); used with RIN1 to generate CSOUT = V(ISP-ISN)/RIN1. |
| CSOUT (28) | Current sense amplifier output | Sources current proportional to ISP/ISN differential; routed to external resistor for voltage output or ADC interface. |
Key Features
| Feature | Design Value |
|---|---|
| Dual current sense amplifiers | Independent ISP/ISN and CSP/CSN paths support simultaneous LED string regulation and input current monitoring up to 100 V. |
| Programmable analog dimming | CTRL pin sets full-scale current threshold from 16 mV to 250 mV with linear 0.25× scaling - enables precise thermal derating and battery C/10 cutoff. |
| TGEN-controlled top-gate enable | Asynchronous PMOS string disable via TGEN pin allows dual-string operation or analog dimming extension without PWM interference. |
| Rail-to-rail ISP/ISN common-mode range | 0–100 V sensing capability eliminates need for level shifters in high-side boost/flyback LED drivers and HV battery chargers. |
| True-color PWM dimming | 3000:1 dimming ratio with minimal color shift achieved via synchronous current regulation and fast gate drivers (20 ns rise, 18 ns fall). |
| Integrated fault protection | Open-LED (VMODE), overcurrent (FAULT), INTVCC UVLO, and thermal shutdown with latched SS discharge requirement ensure robust system reliability. |
Applications
| High-Power Architectural LED Lighting | Dual-String Automotive Headlamp Drivers |
|---|---|
Use Scenario: Driving multiple high-brightness LED strings (e.g., 85 V, 400 mA) in commercial building façade lighting with strict thermal management and long lifetime requirements. IC Role / Device Role / Timing Role: Constant-current controller managing boost topology; regulates LED current via ISP/ISN feedback while using TGEN to selectively deactivate auxiliary strings during low-load conditions. Use Value: Enables dynamic string reconfiguration without firmware intervention, reducing thermal stress and extending LED life by 25% under partial-load operation. | Use Scenario: Independent control of low-beam and high-beam LED arrays in automotive headlamps, requiring fail-safe dimming and ASIL-B compatible fault reporting. IC Role / Device Role / Timing Role: Dual-loop controller using FB1 for CV-based safety margin and ISP/ISN for CC regulation; VMODE/FAULT flags feed microcontroller for ISO 26262 diagnostics. Use Value: Provides hardware-level open-circuit detection and overcurrent shutdown within <100 µs, meeting ASIL-B timing constraints for functional safety. |
| High-Voltage SuperCapacitor Chargers | Industrial UV-C LED Disinfection Systems |
Use Scenario: Charging 75 V supercapacitor banks from 24 V industrial bus with C/10 termination and voltage limiting to prevent electrolyte degradation. IC Role / Device Role / Timing Role: Constant-current/constant-voltage regulator using CTRL pin for C/10 threshold (25 mV) and FB1 for 75 V voltage clamp; ISMON provides real-time charge current telemetry. Use Value: Achieves ±1% charge current accuracy and automatic transition from CC to CV mode at 99.2% of target voltage, extending supercap lifetime by 40%. | Use Scenario: Driving high-power 275 nm UV-C LEDs (120 V, 350 mA) in medical-grade disinfection equipment requiring stable optical output and rapid on/off cycling. IC Role / Device Role / Timing Role: High-voltage boost controller with 100 V absolute max rating; uses PWM input for microsecond-level on/off control and TGEN for standby string isolation. Use Value: Delivers 98.5% current regulation stability across 0–85°C ambient, ensuring consistent germicidal irradiance without spectral drift. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar constant-current LED driver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3789EFE#PBF | Single-output synchronous buck-boost controller; no TGEN pin; supports only one current sense path; 40 V max input. | Best suited for lower-voltage, single-string applications where bidirectional voltage conversion is needed but dual-loop control is unnecessary. | Select LTC3789EFE#PBF only when input voltage stays below 40 V and dual-string or high-side sensing is not required. |
| LT3762EFE#PBF | Single current sense amplifier; no TGEN or dual-FB architecture; lacks ISP/ISN rail-to-rail common-mode range (max 60 V); no ISMON output. | Targeted at cost-sensitive, single-string boost LED drivers with input <60 V and no need for telemetry or redundant regulation loops. | Choose LT3762EFE#PBF for simpler, lower-voltage LED systems where dual-loop redundancy and 100 V capability are not critical. |
Compared with LTC3789EFE#PBF and LT3762EFE#PBF, the LT3796EFE-1#PBF uniquely delivers 100 V ISP/ISN sensing, TGEN-enabled dual-loop control, and integrated ISMON telemetry - making it the only option for high-reliability, high-voltage dual-string LED and supercapacitor charging applications requiring hardware-level fault isolation.
Availability
LT3796EFE-1#PBF is available at Aetrix Electronics and suitable for high-voltage LED lighting, automotive headlamp drivers, and industrial supercapacitor charging applications requiring stable component supply, long-term lifecycle support, and guaranteed -40°C to +125°C operation.
Supply support for LT3796EFE-1#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 acquired Linear Technology in 2017 and maintains full product support, documentation, and manufacturing continuity for the LT3796 family.
The LT3796EFE-1#PBF belongs to Linear's high-voltage LED controller product line, designed specifically for precision constant-current regulation in demanding architectural, automotive, and industrial lighting systems requiring dual-loop control and 100 V capability.
FAQ
What is the maximum input voltage rating for the LT3796EFE-1#PBF?
The LT3796EFE-1#PBF has an absolute maximum input voltage rating of 100 V on VIN, ISP, ISN, CSP, CSN, and VS pins. This allows direct operation from high-voltage industrial buses or photovoltaic sources without external clamping. Operation above 6 V is required for normal regulation, and transient spikes up to 100 V are supported per the datasheet Absolute Maximum Ratings table.
How does the TGEN pin on the LT3796EFE-1#PBF differ from the SYNC pin on the LT3796?
The TGEN pin on the LT3796EFE-1#PBF replaces the SYNC pin found on the LT3796 and serves as a dedicated top-gate enable control. When pulled low, TGEN forces the TG pin high to disable an external PMOS switch independently of PWM timing - enabling dual-string deactivation or analog dimming extension. Unlike SYNC, TGEN does not affect oscillator synchronization or switching frequency.
Can the LT3796EFE-1#PBF regulate both constant-current and constant-voltage simultaneously?
Yes - the LT3796EFE-1#PBF supports simultaneous CC/CV regulation using its dual FB inputs: FB1 regulates voltage (e.g., for overvoltage protection or CV charging), while ISP/ISN regulates current. When FB1 reaches its 1.25 V threshold before current regulation is satisfied, the device transitions to CV mode, preventing overvoltage damage to LEDs or batteries.
What is the purpose of the ISMON pin on the LT3796EFE-1#PBF?
The ISMON pin on the LT3796EFE-1#PBF outputs a voltage proportional to LED current (VISMON = ILED × RLED × 4), providing real-time current telemetry without additional sensing circuitry. This enables system-level monitoring, closed-loop brightness control, or diagnostic logging - especially valuable in safety-critical or remote LED installations where current drift must be tracked.
Does the LT3796EFE-1#PBF require external components for soft-start and fault recovery?
Yes - soft-start is implemented using an external capacitor on the SS pin, charged by an internal 28 µA current source. Fault recovery requires discharging this capacitor below 0.2 V to reset latched faults (e.g., overcurrent, thermal shutdown). A simple RC network or microcontroller-driven discharge circuit ensures controlled restart behavior after fault conditions clear.
LT3796EFE-1#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 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-1#PBF FAQ
1.How can I place an order for LT3796EFE-1#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3796EFE-1#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 LT3796EFE-1#PBF reliable?
The price and inventory of LT3796EFE-1#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3796EFE-1#PBF is usually 5 days.
3.What payment methods are accepted for LT3796EFE-1#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3796EFE-1#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3796EFE-1#PBF?
LT3796EFE-1#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3796EFE-1#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 LT3796EFE-1#PBF?
For technical support, including LT3796EFE-1#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3796EFE-1#PBF requirements.
6.How does Aetrix verify that LT3796EFE-1#PBF is sourced from the original manufacturer or authorized distributors?
All LT3796EFE-1#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 LT3796EFE-1#PBF meets industry standards.
7.What is the process for return or replacement of LT3796EFE-1#PBF?
All LT3796EFE-1#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3796EFE-1#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 LT3796EFE-1#PBF part is unused and in its original packaging.
Return procedure for LT3796EFE-1#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LT3796EFE-1#PBF Tags
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BCR402RE6327HTSA1
Infineon Technologies
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BCR430UXTSA2
Infineon Technologies
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BCR420UE6433HTMA1
Infineon Technologies
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BCR420UE6327HTSA1
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BCR421UE6327HTSA1
Infineon Technologies
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LYT1604D-TL
Power Integrations
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HV9910CLG-G
Microchip Technology
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CL2N8-G
Microchip Technology
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BCR420UW6-7
Diodes Incorporated
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BCR421UW6-7
Diodes Incorporated
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BCR420UFD-7
Diodes Incorporated
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BCR421UFD-7
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