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Analog Devices Inc. LT3745IUJ-1#TRPBF
- Part No.:
- LT3745IUJ-1#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- LED Drivers
- Package:
- 40-WFQFN Exposed Pad
- Datasheet:
-
LT3745IUJ-1#TRPBF.pdf
- Description:
- IC LED DRVR CTRLR PWM 75MA 40QFN
- Quantity:
- Payment:
- Shipping:
Inventory:4,072
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Product details
Overview
LT3745IUJ-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 LT3745IUJ-1#TRPBF datasheet, LT3745IUJ-1#TRPBF pinout, LT3745IUJ-1#TRPBF application, or LT3745IUJ-1#TRPBF equivalent, key selection criteria include its 30MHz cascadable LVDS interface, 0.5µs minimum LED on-time, ±4% inter-channel current matching, thermal/LED fault diagnostics, and 40-lead 6mm × 6mm QFN package with exposed thermal pad.
Technical Context
The LT3745IUJ-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 independently controls up to 75mA with 6-bit dot correction and 12-bit PWM dimming.
Its 30MHz fully-buffered LVDS serial interface enables daisy-chained configuration across multiple devices; fault reporting (open/short LED, overtemperature) is returned via the same interface. The device operates from 6V to 55V input, uses external RT resistor to set switching frequency (200kHz–1MHz), and features dedicated ISET and TSET pins for nominal current and thermal threshold programming.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| LED Channels | 16 independent constant-current sinks, each configurable from 25mA to 75mA |
| Current Matching | ±4% typical mismatch between channels at 50mA - critical for uniform brightness in multi-string displays |
| Dimming Resolution | 12-bit grayscale PWM (4096:1 ratio) with 0.5µs minimum on-time - enables fine-grained brightness control without flicker |
| Buck Input Range | 6V to 55V VIN - supports wide-input industrial and automotive LED power rails |
| Serial Interface | 30MHz cascadable LVDS (SCKI+/−, SDI+/−, SDO+/−, SCKO+/−) + TTL/CMOS LDI - ensures noise-immune, high-speed data chaining |
| Package | 40-lead 6mm × 6mm QFN with exposed GND pad - provides low thermal resistance (θJC = 2.5°C/W) for high-power LED driving |
| Operating Temp | –40°C to +125°C junction temperature - qualified for demanding industrial and outdoor display environments |
Pinout & Package
LT3745IUJ-1#TRPBF is housed in a 40-lead plastic QFN package (6mm × 6mm) with exposed thermal pad (Pin 41 = GND). The package requires soldering of the exposed pad to a continuous PCB ground plane for thermal management and power integrity.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| LED00–LED15 (Pins 2–9, 22–29) | LED cathode current sink outputs | 16 independent linear sinks; each drives up to 75mA into series-connected LEDs up to 36V |
| ISET (Pin 40) | Nominal LED current reference | Resistor-to-ground sets all channel currents; 60.4kΩ yields ~50mA per channel |
| TSET (Pin 39) | Thermal shutdown threshold | Resistor-to-ground programs overtemperature cutoff; 100kΩ sets ~125°C trip point |
| SCKI+/−, SDI+/−, SCKO+/−, SDO+/− (Pins 10–13, 18–21) | LVDS serial interface I/O | Differential clock/data paths enable noise-immune daisy-chaining of multiple ICs at 30MHz |
| LDI (Pin 14) | Asynchronous latch input | TTL/CMOS signal latches incoming GS/DC data into internal registers - decouples timing from LVDS clock domain |
| VIN (Pin 38), GATE (Pin 37), CAP (Pin 36), ISP/ISN (Pins 35/34) | Buck controller power and sensing | Supports external P-MOSFET switch, current-sense resistor, and adaptive bus voltage regulation |
| EN/UVLO (Pin 1), VCC (Pin 15), FB (Pin 33) | Enable, logic supply, and feedback | Enables/disables operation; powers LVDS interface; sets max LED bus voltage via resistor divider |
Key Features
| Feature | Design Value |
|---|---|
| Adaptive LED bus voltage | Dynamic adjustment of buck output to match lowest forward-voltage string - improves system efficiency by minimizing headroom loss |
| Full diagnostic reporting | Individual open/short LED and overtemperature fault status returned via LVDS serial interface - enables real-time display health monitoring |
| 6-bit dot correction | Per-channel analog current trim (64 steps) compensates for LED binning and PCB trace resistance variation - ensures pixel-level luminance uniformity |
| 12-bit grayscale PWM | 4096-step intensity control with sub-microsecond timing resolution - eliminates visible contouring in high-dynamic-range video content |
| Cascadable LVDS interface | 30MHz differential signaling with built-in buffers allows >100-device chains without signal degradation - scales to ultra-large-format signage |
| Thermal protection with programmable threshold | External resistor on TSET pin sets precise overtemperature trip point - avoids premature shutdown while ensuring safe SOA operation |
Applications
| Large-Screen LCD Backlighting | Mono- and Full-Color LED Displays |
|---|---|
|
Use Scenario: Dynamic local dimming in 65"+ commercial LCD panels using segmented LED backlight zones. IC Role / Device Role / Timing Role: LT3745IUJ-1#TRPBF acts as zone-specific LED current controller and bus voltage manager, synchronized to video frame timing via PWMCK input. Use Value: Enables >10,000:1 contrast ratio through per-zone 12-bit dimming and adaptive voltage scaling - reduces power by up to 35% vs fixed-bus designs. |
Use Scenario: High-resolution indoor LED video wall with pixel pitch ≤2.5mm requiring uniform brightness across 10,000+ modules. IC Role / Device Role / Timing Role: LT3745IUJ-1#TRPBF serves as per-module 16-channel driver, receiving grayscale/dot-correction data via daisy-chained LVDS interface. Use Value: ±4% current matching and 6-bit dot correction eliminate visible banding and color shift - meets ISO 12233 visual uniformity standards. |
| Outdoor LED Billboards | Industrial Control Panel Indicators |
|
Use Scenario: 10m×5m highway-facing digital billboard operating continuously under ambient temperatures from –40°C to +85°C. IC Role / Device Role / Timing Role: LT3745IUJ-1#TRPBF drives parallel LED strings per module, with thermal fault detection and UVLO protection against brownouts. Use Value: –40°C to +125°C operation and robust open/short LED diagnostics ensure >99.9% uptime - reduces field service calls by 60%. |
Use Scenario: HMI panel in factory automation system requiring reliable status indication under EMI-heavy motor drive environments. IC Role / Device Role / Timing Role: LT3745IUJ-1#TRPBF powers discrete indicator LEDs with noise-immune LVDS control and fault reporting to PLC. Use Value: Differential LVDS interface rejects >100mV common-mode noise - prevents false status changes during VFD switching transients. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar LED driver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LT3745EUJ-1#TRPBF | Same silicon, extended temperature grade (–40°C to +125°C) with tighter initial current tolerance (±1% vs ±4%) | Preferred for aerospace or military-grade displays where calibration stability is critical | Select when guaranteed ±1% channel matching over full temp range is required; otherwise LT3745IUJ-1#TRPBF offers identical functionality at lower cost |
| MAX20052ATP/V+T | 16-channel 50mA LED driver with I²C interface, no integrated buck controller - requires external DC-DC stage | Suitable for systems with existing 5V/12V bus architecture; lacks adaptive bus voltage and LVDS chaining | Choose when board space permits separate buck converter and I²C control suffices; avoid if adaptive efficiency or >10-device chaining is needed |
Compared with LT3745EUJ-1#TRPBF, the LT3745IUJ-1#TRPBF trades tighter initial matching for cost efficiency while retaining identical pinout, LVDS protocol, and thermal performance; versus MAX20052ATP/V+T, it integrates buck control and LVDS scalability but requires higher VIN and more complex layout.
Availability
LT3745IUJ-1#TRPBF is available at Aetrix Electronics and suitable for large-screen LCD backlighting, mono-/full-color LED displays, outdoor billboards, and industrial HMI panels requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for LT3745IUJ-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 its high-performance analog/mixed-signal product lines, including precision power management ICs for demanding industrial and display applications.
The LT3745IUJ-1#TRPBF belongs to Linear's LED driver portfolio designed specifically for high-channel-count, high-accuracy display illumination - emphasizing adaptive efficiency, diagnostic integrity, and scalable serial control.
FAQ
What is the maximum LED string voltage supported per channel of the LT3745IUJ-1#TRPBF?
The LT3745IUJ-1#TRPBF supports up to 36V LED string voltage per channel, as confirmed by the "LEDxx Operating Voltage" specification (36V min) in the Electrical Characteristics table. This allows driving 10–12 white LEDs in series at typical forward voltages (~3.2V–3.6V each) while maintaining regulation margin. Exceeding 36V risks violating absolute maximum ratings and may trigger open-LED fault detection.
Does the LT3745IUJ-1#TRPBF require an external microcontroller to operate?
No, the LT3745IUJ-1#TRPBF does not require an external microcontroller to function - it operates autonomously once configured. However, a host controller (FPGA, DSP, or MCU) is necessary to send grayscale and dot correction data via its LVDS serial interface. The device includes internal registers, PWM counters, and fault logic that run independently after initialization.
How is thermal protection implemented in the LT3745IUJ-1#TRPBF?
The LT3745IUJ-1#TRPBF implements thermal protection via the TSET pin: an external resistor to ground programs the overtemperature threshold (e.g., 100kΩ sets ~125°C). When die temperature exceeds this threshold, the OT flag is asserted and reported via the LVDS status frame. The device continues operation but disables LED channels if sustained - no automatic shutdown occurs unless externally commanded.
Can the LT3745IUJ-1#TRPBF be used without the integrated buck controller?
Yes, the LT3745IUJ-1#TRPBF's LED driver section can operate with an externally supplied LED bus voltage. To disable the buck controller, tie the SYNC pin to GND or VCC and leave RT, FB, ISP, ISN, GATE, and CAP unconnected or floating (per datasheet recommendations). The 16 current sinks remain fully functional with valid VIN (6V–55V) and proper ISET configuration.
What is the purpose of the LDI pin on the LT3745IUJ-1#TRPBF?
The LDI (Latch Data Input) pin on the LT3745IUJ-1#TRPBF is a TTL/CMOS-compatible asynchronous signal that latches incoming grayscale (GS) or dot correction (DC) data from the 194-bit shift register into the corresponding internal registers. Unlike the LVDS clocked data path, LDI operates independently - enabling precise frame-aligned updates without dependency on SCKI edge timing.
LT3745IUJ-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)
LT3745IUJ-1#TRPBF FAQ
1.How can I place an order for LT3745IUJ-1#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3745IUJ-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 LT3745IUJ-1#TRPBF reliable?
The price and inventory of LT3745IUJ-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 LT3745IUJ-1#TRPBF is usually 5 days.
3.What payment methods are accepted for LT3745IUJ-1#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3745IUJ-1#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3745IUJ-1#TRPBF?
LT3745IUJ-1#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3745IUJ-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 LT3745IUJ-1#TRPBF?
For technical support, including LT3745IUJ-1#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3745IUJ-1#TRPBF requirements.
6.How does Aetrix verify that LT3745IUJ-1#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT3745IUJ-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 LT3745IUJ-1#TRPBF meets industry standards.
7.What is the process for return or replacement of LT3745IUJ-1#TRPBF?
All LT3745IUJ-1#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3745IUJ-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 LT3745IUJ-1#TRPBF part is unused and in its original packaging.
Return procedure for LT3745IUJ-1#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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