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Analog Devices Inc. LT3745EUJ-1#TRPBF
- Part No.:
- LT3745EUJ-1#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- LED Drivers
- Package:
- 40-WFQFN Exposed Pad
- Datasheet:
-
LT3745EUJ-1#TRPBF.pdf
- Description:
- IC LED DRVR CTRLR PWM 75MA 40QFN
- Quantity:
- Payment:
- Shipping:
Inventory:4,472
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Product details
Overview
LT3745EUJ-1#TRPBF 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 and 6-bit dot correction via LVDS serial interface, and targets high-precision dynamic backlighting in large-screen LCDs.
For engineers reviewing the LT3745EUJ-1#TRPBF datasheet, LT3745EUJ-1#TRPBF pinout, LT3745EUJ-1#TRPBF application, or LT3745EUJ-1#TRPBF equivalent, key selection criteria include its 30MHz cascadable LVDS interface, 0.5µs minimum LED on-time, ±1% typical current matching, thermal/LED fault diagnostics, and QFN-40 package compatibility with high-density display PCB layouts.
Technical Context
The LT3745EUJ-1#TRPBF integrates a current-mode nonsynchronous buck controller with sixteen linear current sinks. The buck stage regulates an adaptive output bus voltage (up to 36V) to supply parallel LED strings, while each sink provides programmable 25–75mA constant current with independent 6-bit dot correction and 12-bit PWM control.
Its 30MHz LVDS serial interface uses differential SCKI+/SCKI−, SDI+/SDI−, SCKO+/SCKO−, and SDO+/SDO− signaling for noise-immune cascading across multiple ICs; LDI operates as a TTL/CMOS latch signal. Fault reporting includes per-channel open/short LED detection and overtemperature monitoring via TSET resistor programming.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| LED Channels | 16 independent constant-current sinks, each supporting up to 75mA/36V LED string |
| Current Matching | ±4% max mismatch between channels at 50mA (typical ±1%), enabling uniform brightness across displays |
| PWM Dimming | 12-bit grayscale resolution with 0.5µs minimum on-time, supporting >4000:1 dimming ratio at 500Hz |
| Serial Interface | 30MHz fully-buffered LVDS data path with cascadable SCKO/SDO outputs for multi-chip synchronization |
| Buck Controller | 55V input, adaptive bus voltage regulation, 200kHz–1MHz switching frequency set by RT resistor |
| Package | 40-lead 6mm × 6mm QFN with exposed GND pad; θJC = 2.5°C/W for thermal management in high-power LED systems |
| Operating Temp | –40°C to +125°C junction temperature range, qualified for industrial and automotive display environments |
Pinout & Package
LT3745EUJ-1#TRPBF is housed in a 40-lead 6mm × 6mm plastic QFN package with exposed thermal pad (Pin 41 = GND). The package requires soldering of the exposed pad to a continuous copper ground plane for thermal integrity and power handling.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| LED00–LED15 (Pins 2–9, 22–29) | Constant-current sink outputs | Drive LED string cathodes; each supports 25–75mA with ±4% matching and individual dot correction |
| SCKI+, SCKI− (Pins 10, 11) | LVDS serial clock input | 30MHz differential clock for shifting GS/DC data into internal 194-bit shift register |
| SDI+, SDI− (Pins 12, 13) | LVDS serial data input | Differential data input for 12-bit grayscale (GS) or 6-bit dot correction (DC) frames |
| LDI (Pin 14) | TTL/CMOS latch strobe | Asynchronous edge-triggered signal that latches incoming serial data into GS/DC registers |
| VCC (Pin 15) | Logic supply | 3.0–3.6V supply for LVDS interface and control circuitry; requires local 10µF bypass capacitor |
| PWMCK+, PWMCK− (Pins 16, 17) | LVDS PWM clock input | Drives 12-bit counter for per-channel grayscale timing; supports up to 25MHz operation |
| SDO+, SDO− (Pins 18, 19) | LVDS status data output | Outputs 194-bit status frame including OT flag and per-channel open/short LED fault bits |
| SCKO+, SCKO− (Pins 20, 21) | LVDS serial clock output | Re-driven clock for daisy-chaining to next device; enables synchronous multi-IC timing |
| ISET (Pin 40) | Nominal current reference | Resistor-to-ground sets all 16 channels' base current (e.g., 60.4kΩ → 50mA typical) |
| TSET (Pin 39) | Overtemperature threshold | Resistor-to-ground programs thermal shutdown threshold (e.g., 100kΩ → ~125°C) |
Key Features
| Feature | Design Value |
|---|---|
| Adaptive LED bus voltage | Reduces power loss by dynamically adjusting buck output to match highest-string forward voltage |
| Per-channel 6-bit dot correction | Compensates for LED binning variations and PCB trace resistance differences across 16 channels |
| Full diagnostic reporting | Real-time open/short LED and overtemperature fault status returned via LVDS SDO interface |
| 30MHz cascadable LVDS interface | Enables noise-immune daisy-chaining of dozens of LT3745EUJ-1#TRPBF devices for ultra-large displays |
| 0.5µs minimum LED on-time | Supports high-frequency PWM dimming without visible flicker, critical for HDR and video applications |
Applications
| Large-Screen LCD Backlighting | Mono-Color LED Displays |
|---|---|
|
Use Scenario: Dynamic local dimming in 65″+ LCD TVs and commercial monitors using segmented LED arrays. IC Role / Device Role / Timing Role: LT3745EUJ-1#TRPBF acts as the primary LED current controller and bus voltage regulator, synchronizing 16 zones via LVDS cascade. Use Value: Enables >10,000:1 contrast ratio through precise per-zone current control and adaptive bus voltage scaling. |
Use Scenario: High-brightness signage with uniform monochrome (e.g., red or white) LED modules. IC Role / Device Role / Timing Role: LT3745EUJ-1#TRPBF drives 16 parallel LED strings with matched current and synchronized PWM dimming. Use Value: Eliminates visible brightness gradients across large panels using ±1% typical current matching. |
| Full-Color LED Video Walls | Automotive Display Backlighting |
|
Use Scenario: Indoor/outdoor rental video walls requiring robust thermal management and fault resilience. IC Role / Device Role / Timing Role: LT3745EUJ-1#TRPBF manages RGB subpixel current in modular tiles, reporting open-circuit faults per channel. Use Value: Reduces field failure rate via real-time short/open detection and automatic fault flagging over LVDS. |
Use Scenario: Instrument cluster and center-stack displays with AEC-Q200-compliant thermal performance. IC Role / Device Role / Timing Role: LT3745EUJ-1#TRPBF regulates LED current across 16 segments while maintaining –40°C to +125°C operation. Use Value: Meets automotive EMC requirements via LVDS differential signaling and low EMI buck architecture. |
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#TRPBF | Identical electrical specs and pinout; rated for same –40°C to +125°C temp range but with full industrial-grade characterization and test coverage. | Preferred for mission-critical industrial displays where guaranteed parametric limits across full temperature range are required. | Select LT3745IUJ-1#TRPBF when full production test data across –40°C to +125°C is mandated by system qualification. |
| LT3745EUJ#TRPBF | Omits "-1" suffix; lacks the enhanced open/short LED fault detection logic and optimized 0.5µs on-time capability of the -1 variant. | Suitable only for legacy designs or non-critical backlighting where advanced diagnostics are not needed. | Do not substitute LT3745EUJ#TRPBF for LT3745EUJ-1#TRPBF - missing fault reporting and timing features break compliance with display safety standards. |
Compared with LT3745IUJ-1#TRPBF, the LT3745EUJ-1#TRPBF offers identical functionality at lower cost but with design-in flexibility for less stringent qualification; versus LT3745EUJ#TRPBF, it adds essential fault diagnostics and tighter timing control required for modern HDR displays.
Availability
LT3745EUJ-1#TRPBF is available at Aetrix Electronics and suitable for large-screen LCD backlighting, mono-color LED signage, full-color video walls, and automotive display systems requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for LT3745EUJ-1#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 full product support, documentation, and manufacturing continuity for the LT3745 family.
The LT3745EUJ-1#TRPBF belongs to Linear's high-performance LED driver product line, engineered specifically for precision current regulation and adaptive voltage control in large-area display systems.
FAQ
What is the maximum LED string voltage supported per channel on the LT3745EUJ-1#TRPBF?
The LT3745EUJ-1#TRPBF supports up to 36V LED string voltage per channel, as confirmed by the absolute maximum rating for LEDxx pins (40V) and operational specification under "LEDxx Operating Voltage" (36V). This allows driving 10–12 white LEDs in series at typical forward voltages, provided the adaptive buck bus voltage is configured accordingly via the FB divider network.
Does the LT3745EUJ-1#TRPBF support true 12-bit PWM dimming at full 30MHz interface speed?
Yes, the LT3745EUJ-1#TRPBF supports full 12-bit grayscale PWM dimming with verified 0.5µs minimum LED on-time, enabling >4000:1 dimming ratios even at 500Hz frame rates. Its 30MHz LVDS interface ensures reliable data transfer for 194-bit frames (GS or DC), and timing characteristics confirm tPD-PWM = 55ns propagation delay from PWMCK↑ to ILED edge, preserving timing fidelity.
How is thermal protection implemented on the LT3745EUJ-1#TRPBF?
The LT3745EUJ-1#TRPBF implements thermal protection via the TSET pin: a resistor to ground programs the overtemperature threshold (e.g., 100kΩ yields ~125°C), and the internal comparator triggers an OT flag reported in the SDO status frame. Unlike simple shutdown, this design allows system-level thermal management-host controllers can reduce LED current or disable zones before reaching critical junction temperature.
Can the LT3745EUJ-1#TRPBF be used without the LVDS interface?
No-the LT3745EUJ-1#TRPBF requires the LVDS serial interface (SCKI+/SCKI−, SDI+/SDI−) for configuration and control; there is no parallel or SPI alternative. However, the LDI pin accepts TTL/CMOS logic, and SYNC, EN/UVLO, and RT are single-ended. For basic enable/disable and frequency setting, minimal interface wiring suffices-but full functionality (dimming, dot correction, fault readback) demands the LVDS pair.
What is the purpose of the CAP pin on the LT3745EUJ-1#TRPBF?
The CAP pin on the LT3745EUJ-1#TRPBF serves as the negative terminal of an internal VIN-referenced 6.8V linear regulator that biases the gate driver circuitry. It must be bypassed to VIN with a 0.47µF ceramic capacitor. This architecture isolates gate drive from VCC noise and enables robust P-channel MOSFET switching-even with noisy or unregulated input rails-ensuring stable buck converter operation under dynamic load conditions.
LT3745EUJ-1#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 40-WFQFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- 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#TRPBF FAQ
1.How can I place an order for LT3745EUJ-1#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3745EUJ-1#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 LT3745EUJ-1#TRPBF reliable?
The price and inventory of LT3745EUJ-1#TRPBF 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#TRPBF is usually 5 days.
3.What payment methods are accepted for LT3745EUJ-1#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3745EUJ-1#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3745EUJ-1#TRPBF?
LT3745EUJ-1#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3745EUJ-1#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 LT3745EUJ-1#TRPBF?
For technical support, including LT3745EUJ-1#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3745EUJ-1#TRPBF requirements.
6.How does Aetrix verify that LT3745EUJ-1#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT3745EUJ-1#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 LT3745EUJ-1#TRPBF meets industry standards.
7.What is the process for return or replacement of LT3745EUJ-1#TRPBF?
All LT3745EUJ-1#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3745EUJ-1#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 LT3745EUJ-1#TRPBF part is unused and in its original packaging.
Return procedure for LT3745EUJ-1#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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