My Inquiry
My Account
Analog Devices Inc. LT3743EUFD#PBF
- Part No.:
- LT3743EUFD#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- LED Drivers
- Package:
- 28-WFQFN Exposed Pad
- Datasheet:
-
LT3743EUFD#PBF.pdf
- Description:
- IC LED DRIVER CTRLR PWM 28QFN
- Quantity:
- Payment:
- Shipping:
Inventory:819
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
LT3743EUFD#PBF from Analog Devices (formerly Linear Technology) is a fixed-frequency synchronous step-down DC/DC controller optimized for high-current LED driving, supporting up to 20A output with ±6% current regulation accuracy, 6V–36V input range, and programmable 200kHz–1MHz switching frequency via RT pin. It enables three-state current control (CTRL_L/CTRL_H/CTRL_SEL) and sub-2µs transitions between regulated current levels for precise color mixing in DLP projectors.
For engineers reviewing the LT3743EUFD#PBF datasheet, LT3743EUFD#PBF pinout, LT3743EUFD#PBF application, or LT3743EUFD#PBF equivalent, key selection criteria include its dual-compensation architecture for fast current-state switching, integrated overvoltage/open-LED protection via FB pin, and thermally enhanced 4mm × 5mm QFN package with exposed ground pad.
Technical Context
The LT3743EUFD#PBF implements average current mode control with two independent analog reference inputs (CTRL_L and CTRL_H), each routed through dedicated compensation networks (VCL and VCH) to maintain loop stability during rapid state transitions. Its switched-capacitor topology uses PWMGH and PWMGL outputs to select between two external output capacitors-pre-charged to match respective LED forward voltages-enabling ≤2µs recovery between current states.
Overcurrent protection is cycle-by-cycle and set by CTRL_H with a fixed +23mV offset across SENSE+/SENSE–, while voltage regulation is implemented via a 1.0V FB reference with open-LED detection at 1.3V. The internal 5V VCC_INT regulator powers gate drivers and digital circuitry, and the EN/UVLO pin initiates operation at 1.55V with 130mV hysteresis.
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 - delivered via external high-side and low-side N-channel MOSFETs, not internal switches. |
| Current Regulation Accuracy | ±6% - maintained across 0V to (VIN – 2V) output voltage range using average current mode control. |
| Switching Frequency Range | 200kHz to 1MHz - set by RT resistor; synchronization supported from 240kHz to 1.2MHz on SYNC pin. |
| Recovery Time Between States | <2µs - achieved via dual compensation (VCL/VCH) and independent capacitor switching (PWMGL/PWMGH). |
| Dimming Ratio | Up to 3000:1 - via analog (CTRL_L/CTRL_H) or PWM (PWM/CTRL_SEL) control, enabling high-fidelity color mixing. |
| Shutdown Current | <1µA - ensures minimal system standby power loss when EN/UVLO is pulled low. |
Pinout & Package
LT3743EUFD#PBF is housed in a thermally enhanced 28-lead (4mm × 5mm) plastic QFN package with exposed ground pad (Pin 29), requiring soldering to PCB for thermal and electrical integrity. θJA = 37°C/W.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| GND (Pins 1, 5, 9, 20, 21, 29) | Ground reference and thermal path | Multiple GND pins plus exposed pad reduce impedance and improve heat dissipation in high-current LED driver layouts. |
| CTRL_H / CTRL_L / CTRL_SEL | Analog current reference selection | CTRL_H sets high-level regulated current and overcurrent threshold; CTRL_L sets low-level current; CTRL_SEL toggles between them with <150ns delay to prevent shoot-through. |
| PWMGH / PWMGL | External FET gate drivers for output capacitors | Drive external NMOS switches to connect/disconnect dedicated output capacitors for each current level-enabling µs-scale transitions without inductor recharging delay. |
| SENSE+ / SENSE– | Current sense differential inputs | Measure voltage drop across external sense resistor (RS); internal error amplifier compares to buffered CTRL_H/CTRL_L reference to regulate inductor current. |
| VCH / VCL | Compensation network connections | Accept RC networks (15k–80kΩ + 2nF–10nF) to stabilize current loop separately for high- and low-current regulation states. |
| FB | Voltage regulation and fault sensing | 1.0V reference input; triggers open-LED shutdown at 1.3V and limits output voltage via external resistor divider. |
Key Features
| Feature | Design Value |
|---|---|
| Three-state current control | Enables RGB color mixing by independently regulating two LED current levels (via CTRL_L/CTRL_H) and selecting between them (via CTRL_SEL) with sub-2µs transition. |
| Dual independent compensation | VCH and VCL pins allow separate loop stabilization for high- and low-current states-eliminating instability during rapid dimming transitions. |
| Cycle-by-cycle overcurrent protection | Set by CTRL_H voltage plus fixed 23mV offset at SENSE+–SENSE–; shuts down switching immediately upon violation-no soft-start recovery required. |
| Integrated 5V VCC_INT regulator | Supplies gate drivers and internal circuitry; eliminates need for external bias rail-simplifies BOM and improves startup reliability. |
| Open-LED fault detection | Monitors FB pin; at 1.3V it disables switching and connects both output capacitors to safely discharge inductor energy within 13µs. |
Applications
| Application 1 | Application 2 |
|---|---|
Use Scenario: High-brightness DLP projector illumination system requiring dynamic RGB color balance and flicker-free dimming. IC Role / Device Role / Timing Role: Synchronous step-down controller managing dual-current LED strings with µs-scale transitions between red/green/blue intensity levels. Use Value: Enables true-color rendering via 3000:1 analog dimming and sub-2µs state switching-critical for eliminating color breakup artifacts in high-speed projection. | Use Scenario: Architectural LED lighting fixture with tunable white output (CCT adjustment) and high lumen density. IC Role / Device Role / Timing Role: High-current LED driver delivering up to 20A per channel while maintaining ±6% current matching across parallel strings. Use Value: Ensures consistent luminance and chromaticity across large-area installations via precise current regulation and thermal derating via CTRL_T pin. |
| Application 3 | Application 4 |
Use Scenario: Laser diode driver in medical imaging equipment requiring stable current pulses with minimal overshoot. IC Role / Device Role / Timing Role: Precision current source controlling laser diode anode current using average current mode feedback and fast transient response. Use Value: Delivers accurate pulse amplitude and shape via 6V–36V input tolerance and 200kHz–1MHz programmable frequency-supporting variable pulse widths without loop instability. | Use Scenario: Industrial machine vision lighting with strobed high-intensity illumination synchronized to camera exposure. IC Role / Device Role / Timing Role: PWM-dimming controller triggered by external SYNC signal to align LED current pulses with image capture timing. Use Value: Achieves tight temporal alignment (<100ns jitter) using SYNC pin with 240kHz–1.2MHz lock range-ensuring consistent exposure and eliminating motion blur. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar high-current LED driver controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3783EFE#PBF | Fixed-frequency boost/buck-boost LED controller; no three-state current control; supports up to 10A; requires external op-amps for current regulation. | Better suited for constant-voltage LED arrays or battery-powered boost configurations-not for µs-scale RGB mixing. | Select only if topology requires boost or buck-boost and three-state dimming is unnecessary. |
| LM3409HVMM/NOPB | Constant-current buck controller with single analog dimming input; 1.25A max output; no dual compensation or fast-state switching capability. | Targeted at lower-power indicator or signage LEDs-not for 20A projector or architectural lighting. | Choose only for cost-sensitive, low-current (<2A) applications where fast transitions and precision color mixing are not required. |
Compared with LTC3783EFE#PBF and LM3409HVMM/NOPB, LT3743EUFD#PBF uniquely delivers 20A capability with sub-2µs three-state current switching and dual-loop compensation-making it the only option for high-fidelity DLP color sequencing and high-power tunable-white systems.
Availability
LT3743EUFD#PBF is available at Aetrix Electronics and suitable for DLP projector illumination, high-power architectural lighting, and laser diode driver designs requiring stable component supply, long-term production continuity, and guaranteed lead-free compliance.
Supply support for LT3743EUFD#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 technical and manufacturing continuity for all Linear ICs, including rigorous AEC-Q200-aligned testing for automotive-qualified variants.
The LT3743EUFD#PBF belongs to Linear's high-performance LED driver controller product line, engineered specifically for applications demanding ultra-fast current-state transitions, precise multi-level dimming, and robust fault protection in high-lumen-density lighting systems.
FAQ
What is the maximum regulated LED current achievable with the LT3743EUFD#PBF?
The LT3743EUFD#PBF supports up to 20A regulated LED current when used with appropriately rated external MOSFETs and sense resistors. This is confirmed in the Typical Application section and Electrical Characteristics table, where "92% Efficient 20A LED Driver" is explicitly stated. The actual current is set by the CTRL_H/CTRL_L voltage and external sense resistor RS per the formula IO = VCTRL/(30·RS). The LT3743EUFD#PBF itself does not limit current-it relies on external components and its ±6% regulation accuracy to maintain the target value.
How does the LT3743EUFD#PBF achieve sub-2µs transitions between current states?
The LT3743EUFD#PBF achieves <2µs transitions using a unique switched-capacitor topology: PWMGL and PWMGH drive external FETs to connect two separate output capacitors-one pre-charged to the LED forward voltage at the low-current level (CTRL_L), the other at the high-current level (CTRL_H). With dedicated VCL and VCH compensation networks, the control loop stabilizes instantly upon capacitor switching. The 150ns delay between PWMGH and PWMGL prevents shoot-through, and inductor precharge to 70% of target current further minimizes settling time.
Can the LT3743EUFD#PBF be used in buck-boost or boost topologies?
No-the LT3743EUFD#PBF is a synchronous step-down (buck) controller only. Its block diagram, pin functions (e.g., SW, HG, LG, CBOOT), and application circuits all assume a buck configuration with high-side and low-side external N-channel MOSFETs. It lacks the control logic, gate drive architecture, or reference design support for boost or buck-boost operation. For those topologies, Analog Devices offers alternatives like the LTC3783 or LT3757.
What is the role of the CTRL_T pin on the LT3743EUFD#PBF?
The CTRL_T pin on the LT3743EUFD#PBF provides thermal derating input: applying a voltage to this pin reduces both the CTRL_H and CTRL_L regulated current levels proportionally to prevent overheating under elevated junction temperatures. It is not a shutdown or fault flag-it's an analog scaling input that linearly scales the current references downward as temperature rises, enabling graceful current reduction rather than abrupt thermal shutdown. This supports continuous operation in thermally constrained enclosures.
Does the LT3743EUFD#PBF integrate MOSFETs or require external power switches?
The LT3743EUFD#PBF requires external high-side and low-side N-channel MOSFETs-it contains no integrated power switches. Its HG and LG pins drive the gates of external FETs, while PWMGH and PWMGL drive additional external FETs for output capacitor switching. This architecture allows optimization for voltage, current, and thermal requirements across diverse LED loads. The datasheet explicitly lists recommended MOSFETs (e.g., SiR462DP, Si7234DP) and provides gate drive impedance specs (e.g., HG pull-up = 2.3Ω) to guide selection.
LT3743EUFD#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 28-WFQFN Exposed Pad
- Packaging:
- Tube
- 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-QFN (4x5)
LT3743EUFD#PBF FAQ
1.How can I place an order for LT3743EUFD#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3743EUFD#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 LT3743EUFD#PBF reliable?
The price and inventory of LT3743EUFD#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3743EUFD#PBF is usually 5 days.
3.What payment methods are accepted for LT3743EUFD#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3743EUFD#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3743EUFD#PBF?
LT3743EUFD#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3743EUFD#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 LT3743EUFD#PBF?
For technical support, including LT3743EUFD#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3743EUFD#PBF requirements.
6.How does Aetrix verify that LT3743EUFD#PBF is sourced from the original manufacturer or authorized distributors?
All LT3743EUFD#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 LT3743EUFD#PBF meets industry standards.
7.What is the process for return or replacement of LT3743EUFD#PBF?
All LT3743EUFD#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3743EUFD#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 LT3743EUFD#PBF part is unused and in its original packaging.
Return procedure for LT3743EUFD#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LT3743EUFD#PBF Tags
-
BCR402RE6327HTSA1
Infineon Technologies
-
BCR430UXTSA2
Infineon Technologies
-
BCR420UE6433HTMA1
Infineon Technologies
-
BCR420UE6327HTSA1
Infineon Technologies
-
BCR421UE6327HTSA1
Infineon Technologies
-
LYT1604D-TL
Power Integrations
-
HV9910CLG-G
Microchip Technology
-
CL2N8-G
Microchip Technology
-
BCR420UW6-7
Diodes Incorporated
-
BCR421UW6-7
Diodes Incorporated
-
BCR420UFD-7
Diodes Incorporated
-
BCR421UFD-7
Diodes Incorporated
Tech Hub
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…
Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…
Jumper cables guide covering safe connection order, red and black clamp placement, final ground connection, cable gauge, length, clamp quality, copper vs CCA cables, jump starter comparison and battery…
