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Analog Devices Inc. LT3745EUJ-1#PBF
- Part No.:
- LT3745EUJ-1#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- LED Drivers
- Package:
- 40-WFQFN Exposed Pad
- Datasheet:
-
LT3745EUJ-1#PBF.pdf
- Description:
- IC LED DRVR CTRLR PWM 75MA 40QFN
- Quantity:
- Payment:
- Shipping:
Inventory:4,695
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Product details
Overview
LT3745EUJ-1#PBF from Analog Devices (formerly Linear Technology) is a 16-channel, 50mA constant-current LED driver with integrated 55V buck controller for adaptive LED bus voltage generation. It delivers ±4% LED current matching at 50mA per channel, supports 12-bit grayscale PWM dimming up to 500Hz, and features a cascadable 30MHz LVDS serial interface. It is engineered for large-screen LCD dynamic backlighting requiring precise per-channel current control and high-speed data chaining.
For engineers reviewing the LT3745EUJ-1#PBF datasheet, LT3745EUJ-1#PBF pinout, LT3745EUJ-1#PBF application, or LT3745EUJ-1#PBF equivalent, key selection considerations include its 40-lead 6mm × 6mm QFN package, 6-bit dot correction per channel, ±4% current matching spec, thermal fault reporting via LVDS status frame, and compatibility with P-channel MOSFET gate drive in buck topology.
Technical Context
The LT3745EUJ-1#PBF integrates a current-mode nonsynchronous buck controller with sixteen linear current sinks. The buck stage regulates an adaptive output bus voltage (via FB pin and external resistor divider), while each LED channel uses a precision current sink controlled by ISET and individual 6-bit dot correction registers.
Its 30MHz LVDS serial interface employs differential SCKI+/SCKI–, SDI+/SDI–, SCKO+/SCKO–, and SDO+/SDO– pairs for noise-immune cascading across multiple devices, with TTL/CMOS LDI providing asynchronous latch control. Fault diagnostics-including open/short LED detection and overtemperature flagging-are reported back through the same serial interface in a 194-bit status frame.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VIN Range | 6V to 55V input - enables direct integration into industrial and automotive LED power rails without pre-regulation. |
| LED Current per Channel | 25mA to 75mA (typ 50mA) - programmable via ISET resistor; supports 36V LED string compliance per channel. |
| Current Matching | ±4% (typ ±1%) at 50mA - ensures uniform brightness across 16 parallel LED strings in large-area displays. |
| PWM Dimming | 12-bit grayscale resolution, 500Hz max frequency - delivers >4000:1 contrast ratio with minimal visible flicker. |
| Min LED On-Time | 0.5µs - enables fine-grained temporal control for high-frame-rate video applications and strobing. |
| Serial Interface | 30MHz LVDS clock (SCKI), cascadable - allows daisy-chaining >100 devices with deterministic timing and skew compensation. |
| Package | 40-lead 6mm × 6mm QFN with exposed pad - provides low thermal resistance (θJC = 2.5°C/W) for sustained 50mA/channel operation. |
Pinout & Package
LT3745EUJ-1#PBF is housed in a 40-lead (6mm × 6mm) plastic QFN package with exposed thermal pad (Pin 41 = GND). The exposed pad must be soldered to a continuous PCB ground plane for thermal and electrical integrity.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| EN/UVLO (1) | Enable & Input UVLO Control | Dual-function pin: digital enable (≥1.34V = active) or resistor-divider-programmed VIN undervoltage lockout threshold. |
| LED00–LED15 (2–9, 22–29) | Constant-Current Sink Outputs | 16 independent cathode-side outputs; each sinks up to 75mA with ±4% matching; connect to LED string cathodes. |
| SCKI+/SCKI– (10,11) | LVDS Serial Clock Input | Differential 30MHz clock input for shifting GS/DC data frames into internal 194-bit shift register. |
| SDI+/SDI– (12,13) | LVDS Serial Data Input | Differential data input carrying 194-bit grayscale (C0=0) or dot correction (C0=1) frames. |
| LDI (14) | TTL/CMOS Latch Input | Asynchronous edge-triggered signal that latches incoming serial data into GS/DC registers and initiates status readback. |
| VCC (15) | Logic Supply | 3.0V–3.6V supply for serial interface and control logic; requires local 1µF bypass capacitor to GND. |
| PWMCK+/PWMCK– (16,17) | LVDS PWM Clock Input | Differential clock source for 12-bit grayscale counter; determines PWM frequency and resolution granularity. |
| SDO+/SDO– (18,19) | LVDS Serial Data Output | Differential status frame output (194 bits) containing OT flag, 16× LED fault flags, and DC register values. |
| SCKO+/SCKO– (20,21) | LVDS Serial Clock Output | Differential clock forwarded to next device in cascade; maintains timing alignment across chain. |
| SYNC (30) | Oscillator Sync Input | TTL/CMOS-compatible input to synchronize internal buck switching frequency to external clock (200kHz–1MHz). |
| FB (33) | Buck Output Feedback | Regulated to 1.210V; connects to resistor divider from buck output to set adaptive LED bus voltage level. |
| ISP/ISN (35,34) | Buck Current Sense Inputs | Differential inputs across external sense resistor; set peak current limit (30–58mV threshold) for buck stage. |
| GATE (37) | P-Channel MOSFET Driver | Drives external high-side P-MOSFET gate; supports 1A peak current; requires short, low-inductance PCB trace. |
| VIN (38) | Main Power Input | 6V–55V input; requires local 4.7µF ceramic bypass capacitor to GND near pin. |
| TSET (39) | Overtemperature Threshold | Resistor-to-GND sets junction overtemperature trip point (510mV threshold); enables system-level thermal shutdown. |
| ISET (40) | Nominal LED Current Reference | Resistor-to-GND programs all 16 channels' base current (e.g., 60.4kΩ → 50.5mA typ); trimmed VISET = 1.205V. |
| GND (41) | Thermal & Electrical Ground | Exposed pad; must be soldered to solid copper ground plane for thermal dissipation and noise immunity. |
Key Features
| Feature | Design Value |
|---|---|
| Adaptive LED bus voltage control | Reduces power loss by dynamically adjusting buck output to match minimum forward voltage of active LED strings. |
| Per-channel 6-bit dot correction | Compensates for LED binning and PCB trace resistance variations to achieve <±1% effective current uniformity. |
| Full diagnostic reporting via LVDS | Real-time status frame includes 16× open/short LED flags and TSET-derived overtemperature flag-no extra GPIO required. |
| 0.5µs minimum LED on-time | Enables sub-microsecond pulse control for high-speed strobing, motion blur reduction, and HDR video backlight modulation. |
| 30MHz cascadable LVDS interface | Eliminates signal integrity issues in multi-chip display systems; supports >100-device chains with <5ns inter-device skew. |
Applications
| Large-Screen LCD Backlighting | Mono- and Full-Color LED Displays |
|---|---|
|
Use Scenario: Dynamic local dimming in 65"+ LCD TVs and commercial signage using segmented LED backlight zones. IC Role / Device Role / Timing Role: Primary LED current controller and buck voltage manager; synchronizes PWM dimming across 16 zones via shared PWMCK and per-zone GS registers. Use Value: Enables >10,000:1 contrast ratio through adaptive bus voltage and 12-bit per-zone dimming-reducing power by up to 40% vs fixed-voltage designs. |
Use Scenario: High-resolution outdoor LED billboards with pixel pitch ≤2.5mm requiring uniform brightness across thousands of LEDs. IC Role / Device Role / Timing Role: Constant-current sink array driving 16 parallel LED strings per module; LVDS cascade links modules into single serial chain. Use Value: ±4% current matching and 6-bit dot correction eliminate visible banding or color shift across modules without manual calibration. |
| Automotive Center Stack Displays | Medical Imaging Backlights |
|
Use Scenario: AEC-Q200-compliant infotainment display backlight with extended temperature operation (–40°C to 125°C). IC Role / Device Role / Timing Role: LED driver with integrated thermal protection (TSET pin) and fault reporting; operates across full automotive temp range without derating. Use Value: Built-in open/short LED diagnostics reduce BOM count and enable ASIL-B compliant failure mode analysis without external monitoring ICs. |
Use Scenario: DICOM-compliant medical monitor backlight requiring flicker-free, stable luminance over 8+ hours of continuous operation. IC Role / Device Role / Timing Role: Precision current regulator with <0.2%/V line/load regulation; minimizes luminance drift due to input or LED Vf variation. Use Value: 0.5µs min on-time and jitter-free LVDS timing ensure zero visible PWM artifacts during fluoroscopy or real-time imaging. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar LED driver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LT3745IUJ-1#PBF | Identical functionality and pinout; rated for –40°C to 125°C with full guaranteed specs across range (vs E-grade's assured-by-design spec at extremes). | Required for automotive or industrial applications demanding production-tested performance at temperature boundaries. | Select LT3745IUJ-1#PBF when full temperature-range validation is mandated by design qualification or safety standards. |
| MAX20052ATP/V+T | 16-channel 50mA LED driver with I²C interface (not LVDS), no integrated buck controller-requires external DC-DC stage. | Suitable for space-constrained designs where serial interface simplicity outweighs need for adaptive voltage control. | Choose MAX20052ATP/V+T only if existing 12V/24V rail is available and LVDS noise immunity or buck integration is not required. |
Compared with LT3745IUJ-1#PBF, the LT3745EUJ-1#PBF offers identical electrical performance but with production-tested specs limited to 0°C–125°C junction; versus MAX20052ATP/V+T, it eliminates external buck components and adds LVDS noise resilience at the cost of interface complexity.
Availability
LT3745EUJ-1#PBF is available at Aetrix Electronics and suitable for large-screen LCD backlighting, outdoor LED signage, and automotive center stack displays requiring stable component supply, long-term lifecycle support, and consistent parametric performance across production batches.
Supply support for LT3745EUJ-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) is a global leader in high-performance analog, mixed-signal, and power management semiconductors, serving industrial, automotive, communications, and healthcare markets.
The LT3745EUJ-1#PBF belongs to Linear's high-efficiency LED driver product line, designed specifically for large-format display systems demanding adaptive voltage control, per-channel precision dimming, and robust serial communication in electrically noisy environments.
FAQ
What is the maximum LED string voltage supported per channel of the LT3745EUJ-1#PBF?
The LT3745EUJ-1#PBF supports up to 36V LED string voltage per channel, as confirmed by the "LEDxx Operating Voltage" specification (l = –40°C to 125°C) in the Absolute Maximum Ratings and Electrical Characteristics tables. This allows driving typical white LED strings of 10–12 devices in series at standard forward voltages.
Does the LT3745EUJ-1#PBF require an external buck converter, or is it integrated?
The LT3745EUJ-1#PBF integrates a complete 55V nonsynchronous buck controller-including gate driver (GATE pin), current sense inputs (ISP/ISN), feedback (FB), and oscillator programming (RT)-so no external buck IC is needed. It drives an external P-channel MOSFET to generate the adaptive LED bus voltage.
How does the LT3745EUJ-1#PBF report open or short LED faults?
The LT3745EUJ-1#PBF reports open/short LED faults via its 194-bit LVDS status frame (SDO+/SDO–), which includes 16 dedicated fault flag bits-one per LED channel-alongside the overtemperature flag and dot correction register values, all transmitted synchronously with SCKO.
Can the LT3745EUJ-1#PBF operate without the LVDS interface enabled?
Yes-the LT3745EUJ-1#PBF functions with LED channels disabled by default after power-on reset. While the LVDS interface is required for configuration (grayscale/dot correction) and fault readback, the buck controller and current sinks remain operational if static settings are preloaded and LDI is held inactive.
What is the thermal resistance (θJC) of the LT3745EUJ-1#PBF package?
The LT3745EUJ-1#PBF in its 40-lead 6mm × 6mm QFN package has a junction-to-case thermal resistance (θJC) of 2.5°C/W, as specified in the Pin Configuration diagram footnote. This value assumes proper soldering of the exposed pad (Pin 41) to a continuous PCB ground plane.
LT3745EUJ-1#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 40-WFQFN Exposed Pad
- Packaging:
- Tube
- Product Status:
- Active
- Type:
- DC DC Controller
- Topology:
- Step-Down (Buck)
- Internal Switch(s):
- No
- Number of Outputs:
- 16
- Voltage - Supply (Min):
- 6V
- Voltage - Supply (Max):
- 55V
- Voltage - Output:
- 36V
- Current - Output / Channel:
- 75mA
- Frequency:
- 200kHz ~ 1MHz
- Dimming:
- PWM
- Applications:
- Backlight, Signage
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 40-QFN (6x6)
LT3745EUJ-1#PBF FAQ
1.How can I place an order for LT3745EUJ-1#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3745EUJ-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 LT3745EUJ-1#PBF reliable?
The price and inventory of LT3745EUJ-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 LT3745EUJ-1#PBF is usually 5 days.
3.What payment methods are accepted for LT3745EUJ-1#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3745EUJ-1#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3745EUJ-1#PBF?
LT3745EUJ-1#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3745EUJ-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 LT3745EUJ-1#PBF?
For technical support, including LT3745EUJ-1#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3745EUJ-1#PBF requirements.
6.How does Aetrix verify that LT3745EUJ-1#PBF is sourced from the original manufacturer or authorized distributors?
All LT3745EUJ-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 LT3745EUJ-1#PBF meets industry standards.
7.What is the process for return or replacement of LT3745EUJ-1#PBF?
All LT3745EUJ-1#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3745EUJ-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 LT3745EUJ-1#PBF part is unused and in its original packaging.
Return procedure for LT3745EUJ-1#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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