My Inquiry
My Account
Analog Devices Inc. LT3743EFE#PBF
- Part No.:
- LT3743EFE#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- LED Drivers
- Package:
- 28-TSSOP (0.173", 4.40mm Width) Exposed Pad
- Datasheet:
-
LT3743EFE#PBF.pdf
- Description:
- IC LED DRIVER CTRLR PWM 28TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:1,333
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
LT3743EFE#PBF 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 LED current, supports 6V–36V input, achieves ±6% current regulation accuracy, and enables sub-2µs transitions between two current levels-used in DLP projectors for RGB color mixing via rapid analog/PWM dimming.
For engineers reviewing the LT3743EFE#PBF datasheet, LT3743EFE#PBF pinout, LT3743EFE#PBF application, or LT3743EFE#PBF equivalent, key selection considerations include its dual-compensation average current mode architecture, CTRL_SEL–driven fast current-state switching, 28-pin TSSOP thermal performance (θJA = 30°C/W), and integrated overvoltage/open-LED protection via FB pin.
Technical Context
The LT3743EFE#PBF implements average current mode control with two independent reference inputs (CTRL_H/CTRL_L), each routed through dedicated compensation networks (VCH/VCL) to maintain loop stability across distinct current states. Its switched-capacitor topology uses PWMGH/PWMGL outputs to select between two output capacitors-enabling <2µs recovery between regulated current levels without compromising regulation accuracy.
Current regulation is set by voltage on CTRL_H (0–1.5V, clamped) and CTRL_L (0–1.5V), translating to 48–54mV sensed differential across RS via internal gm amplifier (475µA/V). Overcurrent protection is cycle-by-cycle, triggered at CTRL_H-set level +23mV SENSE+–SENSE– offset, while voltage regulation engages when FB exceeds 1.0V and shuts down switching at 1.3V (open-LED flag).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 6V to 36V - supports wide industrial and automotive LED power rails without external pre-regulation. |
| Max Output Current | 20A - delivered via external high-side/low-side MOSFETs; requires ≥20% inductor saturation margin. |
| Current Regulation Accuracy | ±6% - maintained over temperature and output voltage range (0V to VIN – 2V). |
| Switching Frequency Range | 200kHz to 1MHz - set by RT resistor; sync-compatible up to 1.2MHz with 20% margin. |
| Recovery Time Between States | <2µs - enables true-color PWM dimming with 3000:1 ratio in projector color-mixing applications. |
| Shutdown Quiescent Current | <1µA - minimizes standby power loss in battery-backed or always-on lighting systems. |
| Thermal Resistance (θJA) | 30°C/W - measured for 28-pin TSSOP package with exposed pad soldered to PCB ground plane. |
Pinout & Package
LT3743EFE#PBF is housed in a 28-lead plastic TSSOP package with exposed thermal pad (Pin 29 = GND). The package measures 9.7mm × 4.4mm × 1.1mm and requires PCB-level thermal management via soldered exposed pad.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| GND (Pins 2, 7, 11, 22, 27, Exposed Pad 29) | Power and signal reference ground | Multiple GND pins and exposed pad reduce impedance and improve thermal dissipation; pad must be soldered. |
| CTRL_H / CTRL_L / CTRL_SEL | Analog current reference selection interface | CTRL_H sets high-current level (0–1.5V); CTRL_L sets low level; CTRL_SEL selects between them with 150ns delay to prevent capacitor shoot-through. |
| PWMGH / PWMGL | External FET gate drivers for output capacitor switching | Drive external NMOS switches to connect/disconnect dedicated output capacitors per current state; 3.2Ω pull-up / 1.75Ω pull-down impedance. |
| SENSE+ / SENSE− | Differential current sense inputs | Measure voltage drop across external sense resistor (RS); internal gm amp converts to regulated inductor current with 475µA/V transconductance. |
| VCH / VCL | Compensation network connections | Separate RC networks (15k–80k Ω, 2nF–10nF) stabilize current loop for high/low current states independently. |
Key Features
| Feature | Design Value |
|---|---|
| Three-State Current Control | Enables precise RGB LED color mixing in DLP projectors by switching between two analog-set current levels plus zero-current PWM off-state. |
| True Color PWM Dimming | 3000:1 dimming ratio achieved via synchronized CTRL_SEL and PWM signals with <2µs transition-no visible color shift during brightness changes. |
| Dual Compensation Architecture | VCH and VCL pins allow independent loop tuning for high/low current states, eliminating instability during rapid state transitions. |
| Integrated Open-LED Protection | FB pin monitors output voltage; at 1.3V it triggers 13µs shutdown and discharges inductor via both output capacitors-preventing LED overvoltage damage. |
| Robust Overcurrent Protection | Cycle-by-cycle limiting at CTRL_H-set level +23mV offset ensures immediate response without soft-start delay-critical for high-power LED reliability. |
Applications
| DLP Projector Light Engine | High-Power Architectural Lighting |
|---|---|
Use Scenario: RGB LED arrays require microsecond-level current switching to generate pure colors without hue shift during brightness modulation. IC Role / Device Role / Timing Role: LT3743EFE#PBF acts as a dual-state synchronous buck controller with independent current regulation loops and switched-capacitor topology. Use Value: Enables <2µs current-state transitions and 3000:1 dimming ratio-meeting DLP color fidelity and flicker-free requirements. |
Use Scenario: Outdoor LED luminaires demand stable 10–20A drive under wide ambient temperature and input voltage variation (e.g., 12–36V solar/battery systems). IC Role / Device Role / Timing Role: LT3743EFE#PBF provides average current mode control with ±6% accuracy and open-LED fault detection. Use Value: Maintains consistent lumen output despite LED Vf drift and prevents catastrophic failure during LED string open-circuit events. |
| Laser Diode Driver | Industrial Machine Vision Illumination |
Use Scenario: Pulsed laser diodes require precise, repeatable current pulses with minimal overshoot and fast turn-off to avoid thermal runaway. IC Role / Device Role / Timing Role: LT3743EFE#PBF serves as a programmable current source with cycle-by-cycle overcurrent limiting and <1µA shutdown current. Use Value: Delivers accurate current pulses up to 20A with 23mV overcurrent threshold margin-ensuring safe diode operation. |
Use Scenario: High-speed inspection systems need strobed LED illumination synchronized to camera exposure with nanosecond timing precision. IC Role / Device Role / Timing Role: LT3743EFE#PBF functions as a PWM-gated current controller with 10ns-level signal propagation (CTRL_SEL → PWMGH delay). Use Value: Supports sub-microsecond strobe timing and eliminates residual current tail-critical for motion-blur-free imaging. |
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 | Single-output, no CTRL_SEL pin; lacks three-state control and <2µs transition capability; supports only one regulated current level. | Suitable for constant-current LED drivers without color mixing or rapid dimming needs. | Select LTC3783EFE#PBF only when dual-state switching is unnecessary and board space allows larger external compensation components. |
| LM3423MH/NOPB | Asynchronous buck controller; no integrated gate drivers; requires external high-side driver; max 5A output; no VCH/VCL dual compensation. | Targeted at mid-power LED applications (<5A) with simpler thermal and layout constraints. | Choose LM3423MH/NOPB for cost-sensitive, lower-current designs where <2µs transitions and 20A capability are not required. |
Compared with LTC3783EFE#PBF and LM3423MH/NOPB, the LT3743EFE#PBF uniquely delivers three-state current control with sub-2µs transitions, dual compensation, and integrated PWMGH/PWMGL drivers-making it the only option for DLP projector-grade RGB mixing and high-fidelity PWM dimming above 10A.
Availability
LT3743EFE#PBF is available at Aetrix Electronics and suitable for DLP projector light engines, high-power architectural lighting, and industrial machine vision illumination requiring stable component supply, long-term BOM continuity, and guaranteed lead-free compliance.
Supply support for LT3743EFE#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 all Linear ICs including the LT3743 series.
The LT3743 product line was designed specifically for high-current, high-dynamic-range LED driving-emphasizing fast current-state transitions, robust fault protection, and analog/PWM hybrid dimming for professional display and illumination systems.
FAQ
What is the maximum regulated LED current achievable with the LT3743EFE#PBF?
The LT3743EFE#PBF supports up to 20A regulated LED current when paired with appropriately rated external MOSFETs and inductors. This is confirmed in the Typical Application section and Electrical Characteristics table, where "92% Efficient 20A LED Driver" is explicitly stated. The actual current depends on the external sense resistor value (RS) and CTRL_H voltage, per the formula IO = VCTRL / (30 × RS). For example, with VCTRL_H = 1.5V and RS = 2.5mΩ, LT3743EFE#PBF delivers 20A.
How does the LT3743EFE#PBF achieve <2µs current-state transitions?
The LT3743EFE#PBF achieves <2µs transitions using a switched-capacitor topology with two independent output capacitors and dedicated PWMGH/PWMGL gate drivers. When CTRL_SEL toggles, a 150ns delay prevents shoot-through, then PWMGH or PWMGL connects the pre-charged capacitor matching the target current level. The inductor is precharged to 70% of the new regulation level immediately after the gate signal asserts-verified in Typical Performance Characteristic Figure G30. This architecture is intrinsic to LT3743EFE#PBF and not dependent on external components.
What is the function of the VCH and VCL pins on the LT3743EFE#PBF?
VCH and VCL are dedicated compensation network connections for the average current mode control loop-one for the high-current state (VCH) and one for the low-current state (VCL). Each accepts a series RC network (typically 15k–80k Ω resistor and 2nF–10nF capacitor) to stabilize the error amplifier during its respective regulation mode. This dual-compensation design prevents loop instability during rapid CTRL_SEL transitions and is a defining feature of LT3743EFE#PBF's architecture.
Does the LT3743EFE#PBF provide open-LED protection, and how does it work?
Yes, the LT3743EFE#PBF provides open-LED protection via the FB pin. When the feedback voltage exceeds 1.3V-indicating an open LED string-the device disables switching for 13µs and simultaneously connects both output capacitors to fully discharge the inductor current. This action prevents damaging voltage spikes and is documented in the Block Diagram (Figure 1), Applications Information, and Typical Performance Characteristic G15–G16. The 1.0V FB regulation threshold and 1.3V lockout threshold are hard-coded internal references in LT3743EFE#PBF.
What is the thermal performance difference between the LT3743EFE#PBF (TSSOP) and LT3743EUFD#PBF (QFN)?
The LT3743EFE#PBF in 28-lead TSSOP has θJA = 30°C/W, while the LT3743EUFD#PBF in 4mm × 5mm QFN has θJA = 37°C/W-making the TSSOP variant thermally superior for high-power operation. This 7°C/W difference arises from the TSSOP's larger exposed pad area and more favorable PCB copper spreading characteristics. Both packages share identical junction temperature limits (TJMAX = 125°C), but LT3743EFE#PBF sustains higher continuous current in constrained thermal environments without derating.
LT3743EFE#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 28-TSSOP (0.173", 4.40mm Width) 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-TSSOP-EP
LT3743EFE#PBF FAQ
1.How can I place an order for LT3743EFE#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3743EFE#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 LT3743EFE#PBF reliable?
The price and inventory of LT3743EFE#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3743EFE#PBF is usually 5 days.
3.What payment methods are accepted for LT3743EFE#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3743EFE#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3743EFE#PBF?
LT3743EFE#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3743EFE#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 LT3743EFE#PBF?
For technical support, including LT3743EFE#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3743EFE#PBF requirements.
6.How does Aetrix verify that LT3743EFE#PBF is sourced from the original manufacturer or authorized distributors?
All LT3743EFE#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 LT3743EFE#PBF meets industry standards.
7.What is the process for return or replacement of LT3743EFE#PBF?
All LT3743EFE#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3743EFE#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 LT3743EFE#PBF part is unused and in its original packaging.
Return procedure for LT3743EFE#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LT3743EFE#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…
