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Analog Devices Inc. LT3743EFE#TRPBF
- Part No.:
- LT3743EFE#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- LED Drivers
- Package:
- 28-TSSOP (0.173", 4.40mm Width) Exposed Pad
- Datasheet:
-
LT3743EFE#TRPBF.pdf
- Description:
- IC LED DRIVER CTRLR PWM 28TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:2,278
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Product details
Overview
LT3743EFE#TRPBF from Analog Devices (formerly Linear Technology) is a fixed-frequency synchronous step-down DC/DC controller optimized for high-current LED driving with three-state current control. It delivers up to 20A regulated output, supports 6V–36V input, achieves ±6% current regulation accuracy, and enables sub-2µs transitions between two programmable current levels-used in DLP projectors for precise RGB color mixing.
For engineers reviewing the LT3743EFE#TRPBF datasheet, LT3743EFE#TRPBF pinout, LT3743EFE#TRPBF application, or LT3743EFE#TRPBF equivalent, key selection criteria include its dual-analog-control architecture (CTRL_L/CTRL_H), 200kHz–1MHz programmable switching frequency, integrated 5V VCC_INT regulator, and TSSOP-28 package with exposed thermal pad for high-power thermal management.
Technical Context
The LT3743EFE#TRPBF implements average current mode control using dual independent compensation networks (VCH/VCL) to maintain stable regulation at both high and low current states. Its switched-capacitor topology allows rapid state transitions by dynamically selecting between two external output capacitors via PWMGH/PWMGL outputs.
Current regulation is set by analog voltages on CTRL_H (0–1.5V, sets high-level current and overcurrent threshold) and CTRL_L (0–1.5V, sets low-level current), with state selection via CTRL_SEL. Overvoltage protection triggers at FB = 1.3V, initiating open-LED shutdown and inductor discharge.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 6V to 36V - supports wide industrial and automotive supply rails without external pre-regulation. |
| Max Output Current | 20A - enables direct drive of high-brightness LED arrays and laser diodes without external current amplification. |
| Current Regulation Accuracy | ±6% - ensures consistent luminance across temperature and unit-to-unit variation in lighting systems. |
| Switching Frequency Range | 200kHz to 1MHz - adjustable via RT resistor; higher frequencies reduce inductor size, lower frequencies improve efficiency at high current. |
| Recovery Time Between States | <2µs - critical for high-fidelity PWM dimming and real-time color mixing in projection applications. |
| Shutdown Current | <1µA - minimizes standby power loss in battery-backed or energy-sensitive systems. |
| VCC_INT Output | 5V @ ~50mA - powers internal circuitry and charges CBOOT capacitor; eliminates need for external bias supply. |
Pinout & Package
LT3743EFE#TRPBF uses a 28-lead plastic TSSOP package with exposed thermal pad (Pin 29 = GND), rated for –40°C to +125°C junction temperature and θJA = 30°C/W.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN (Pin 3) | Main power input | Accepts 6–36V; requires local 1µF low-ESR bypass to GND for stability. |
| EN/UVLO (Pin 4) | Enable & undervoltage lockout | Turns on core bias at 1.55V; full shutdown below ~0.5V; no internal pull-up/down. |
| CTRL_H / CTRL_L (Pins 8 / 9) | Analog current reference inputs | 0–1.5V range sets high/low regulated LED current; internally clamped to prevent overrange. |
| CTRL_SEL (Pin 19) | Current level selector | High = use CTRL_H reference; low = use CTRL_L reference; enables fast state switching. |
| PWM (Pin 20) | Global PWM dimming input | Low = zero-current shutdown with capacitor disconnect; high = active regulation per CTRL_SEL state. |
| PWMGH / PWMGL (Pins 21 / 23) | External capacitor switch drivers | Drive external FET gates to select high/low-current output capacitors; 3.2Ω pull-up / 1.75Ω pull-down impedance. |
| HG / LG (Pins 24 / 28) | High-side / low-side gate drivers | Drive external N-MOSFETs; 2.3Ω/1.3Ω (HG), 2.5Ω/1.3Ω (LG) on-resistance ensures fast switching at 20A. |
| SENSE+ / SENSE– (Pins 13 / 14) | Current sense differential inputs | Measure voltage drop across external sense resistor (RS); enable cycle-by-cycle overcurrent protection. |
| FB (Pin 12) | Voltage regulation feedback | 1.0V reference; >1.3V triggers open-LED shutdown and inductor discharge. |
| VCC_INT (Pin 1) | Internal 5V regulator output | Supplies internal logic and charges CBOOT; current-limited to ~50mA; disable during shutdown. |
Key Features
| Feature | Design Value |
|---|---|
| Three-state current control | Enables precise RGB color mixing in DLP projectors by rapidly toggling between two independently set LED currents. |
| True Color PWM dimming | Delivers up to 3000:1 dimming ratio with minimal color shift via synchronized CTRL_SEL and PWM control. |
| Dual compensation networks (VCH/VCL) | Ensures loop stability across both high- and low-current operating points without manual re-tuning. |
| Integrated 5V VCC_INT regulator | Reduces BOM count by powering internal circuitry and charging CBOOT, eliminating need for external LDO. |
| Cycle-by-cycle overcurrent protection | Uses CTRL_H voltage plus 23mV offset to set fast-acting current limit, protecting LEDs and MOSFETs during fault conditions. |
Applications
| DLP Projectors | High-Power Architectural Lighting |
|---|---|
Use Scenario: Real-time RGB color sequencing in digital light processing engines requiring microsecond-level current switching. IC Role / Device Role / Timing Role: Synchronous step-down controller with dual-analog current references and switched-capacitor topology for sub-2µs state transitions. Use Value: Enables accurate color fidelity and flicker-free operation by maintaining ±6% current regulation while switching between 0A–20A states. | Use Scenario: High-efficiency, thermally robust illumination of façades and large indoor spaces using multi-string high-brightness LEDs. IC Role / Device Role / Timing Role: Fixed-frequency average current mode controller delivering up to 20A with integrated thermal derating (CTRL_T input). Use Value: Supports long-life operation under continuous 24/7 duty cycles with <1µA shutdown current and robust overvoltage/open-LED protection. |
| Laser Diode Drivers | Industrial Machine Vision Lighting |
Use Scenario: Pulsed or modulated drive of high-power laser diodes in material processing and medical equipment. IC Role / Device Role / Timing Role: Precision current source with programmable overcurrent threshold and fast recovery (<2µs) for pulse shaping. Use Value: Maintains tight current regulation (±6%) across wide temperature ranges (–40°C to +125°C), ensuring consistent optical output power. | Use Scenario: Stroboscopic or synchronized illumination for high-speed camera capture in automated inspection systems. IC Role / Device Role / Timing Role: PWM-dimmable current controller with 3000:1 dimming ratio and 200kHz–1MHz frequency tuning for EMI control. Use Value: Eliminates visible flicker and enables precise exposure timing via hardware-controlled PWM and CTRL_SEL signals. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar high-current LED driver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3783EFE#TRPBF | Fixed-frequency, average current mode controller with single current reference; no CTRL_SEL or dual-compensation; max 15A output. | Lacks three-state control and sub-2µs transition capability; suitable only for single-level dimming. | Select when dual-current-state operation is unnecessary and cost reduction is prioritized over color-mixing performance. |
| LM3409QMH/NOPB | Constant-current buck controller with analog/PWM dimming; no switched-capacitor topology; max 5A output; automotive-grade AEC-Q100. | Designed for automotive LED headlamps; lacks high-current capability and fast-state-switching features. | Select for automotive applications requiring AEC-Q100 qualification and moderate current (≤5A), not for projector-grade color mixing. |
Compared with LTC3783EFE#TRPBF and LM3409QMH/NOPB, the LT3743EFE#TRPBF uniquely supports microsecond-level current state transitions and true three-state control-making it irreplaceable for DLP projection and precision laser diode modulation where dual-reference accuracy and speed are mandatory.
Availability
LT3743EFE#TRPBF is available at Aetrix Electronics and suitable for DLP projectors, high-power architectural lighting, laser diode drivers, industrial machine vision lighting, and RGB color-mixing systems requiring stable component supply across extended temperature ranges.
Supply support for LT3743EFE#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 its legacy of high-performance analog ICs for power management, signal conditioning, and precision control.
The LT3743EFE#TRPBF belongs to Linear's high-current LED driver product line, designed specifically for applications demanding fast, accurate, and thermally robust current regulation in projection, stage lighting, and industrial laser systems.
FAQ
What is the maximum regulated output current supported by the LT3743EFE#TRPBF?
The LT3743EFE#TRPBF supports up to 20A regulated LED current, achieved through external N-channel MOSFETs and a precision current-sense amplifier. This rating assumes proper thermal design-including soldering the exposed pad (Pin 29) to a PCB thermal plane-and use of low-resistance sense resistors (e.g., 2mΩ for 20A). The LT3743EFE#TRPBF maintains ±6% regulation accuracy across its full operating temperature range (–40°C to +125°C).
How does the LT3743EFE#TRPBF achieve sub-2µs transitions between current states?
The LT3743EFE#TRPBF achieves sub-2µs transitions using a switched-capacitor topology: two external output capacitors are selectively engaged via PWMGH and PWMGL outputs, each pre-charged to the forward voltage corresponding to its assigned current level (CTRL_H or CTRL_L). A 150ns interlock prevents simultaneous conduction, and inductor precharging ensures immediate current delivery. This architecture is explicitly validated in the LT3743EFE#TRPBF datasheet Figure G31 and G32 waveforms.
Can the LT3743EFE#TRPBF be used for constant-voltage regulation?
Yes-the LT3743EFE#TRPBF includes voltage regulation via the FB pin, with a 1.0V internal reference. When the output voltage rises above the threshold set by an external resistor divider, the controller reduces inductor current to clamp voltage. If FB exceeds 1.3V, it triggers open-LED protection, halting switching and discharging the inductor. This dual-mode (current/voltage) operation is documented in the LT3743EFE#TRPBF Electrical Characteristics table and Operation section.
What is the role of the CTRL_T pin on the LT3743EFE#TRPBF?
The CTRL_T pin on the LT3743EFE#TRPBF provides thermal derating: applying a voltage (typically from an NTC thermistor network) reduces both CTRL_H and CTRL_L reference levels proportionally, lowering regulated LED current as temperature rises. This feature protects LEDs and external MOSFETs during thermal overload and is explicitly defined in the LT3743EFE#TRPBF Pin Functions section and Applications Information.
Does the LT3743EFE#TRPBF require external bootstrap components?
Yes-the LT3743EFE#TRPBF requires an external Schottky diode from VCC_INT (Pin 1) to CBOOT (Pin 26) and a ceramic capacitor (typically 100nF) from CBOOT to SW (Pin 25) to generate the floating 5V supply for the high-side gate driver. This bootstrap configuration is mandatory for HG output operation and is shown in the LT3743EFE#TRPBF Typical Application schematic (Figure TA01a) and Pin Functions description.
LT3743EFE#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 28-TSSOP (0.173", 4.40mm Width) Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Type:
- DC DC Controller
- Topology:
- Step-Down (Buck)
- Internal Switch(s):
- No
- Number of Outputs:
- 1
- Voltage - Supply (Min):
- 6V
- Voltage - Supply (Max):
- 36V
- Voltage - Output:
- -
- Current - Output / Channel:
- -
- Frequency:
- 200kHz ~ 1MHz
- Dimming:
- PWM
- Applications:
- Lighting
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 28-TSSOP-EP
LT3743EFE#TRPBF FAQ
1.How can I place an order for LT3743EFE#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3743EFE#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 LT3743EFE#TRPBF reliable?
The price and inventory of LT3743EFE#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3743EFE#TRPBF is usually 5 days.
3.What payment methods are accepted for LT3743EFE#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3743EFE#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3743EFE#TRPBF?
LT3743EFE#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3743EFE#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 LT3743EFE#TRPBF?
For technical support, including LT3743EFE#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3743EFE#TRPBF requirements.
6.How does Aetrix verify that LT3743EFE#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT3743EFE#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 LT3743EFE#TRPBF meets industry standards.
7.What is the process for return or replacement of LT3743EFE#TRPBF?
All LT3743EFE#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3743EFE#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 LT3743EFE#TRPBF part is unused and in its original packaging.
Return procedure for LT3743EFE#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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