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Analog Devices Inc. LT8500ETJ#TRPBF
- Part No.:
- LT8500ETJ#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- LED Drivers
- Package:
- 56-VTLA Exposed Pad
- Datasheet:
-
LT8500ETJ#TRPBF.pdf
- Description:
- IC PWM GENERATOR 56-TLAQFN
- Quantity:
- Payment:
- Shipping:
Inventory:3,002
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Product details
Overview
LT8500ETJ#TRPBF from Analog Devices is a 48-channel, 12-bit PWM generator IC designed for high-precision LED backlighting and display control. It delivers independent 4096-step PWM outputs with ±50% per-channel correction, 50MHz cascadable serial interface, and phase-shifted bank operation (120°) to reduce EMI. It directly drives three LT3595A LED drivers in large-screen LCD and full-color LED signage applications.
For engineers reviewing the LT8500ETJ#TRPBF datasheet, LT8500ETJ#TRPBF pinout, LT8500ETJ#TRPBF application, or LT8500ETJ#TRPBF equivalent, key selection considerations include its 56-pin TLA QFN package, 3V–5.5V supply range, diagnostic open-LED/sync-error flags, 6.1kHz max PWM frequency at 25MHz PWMCK, and cascaded 5-wire serial topology supporting up to dozens of daisy-chained units.
Technical Context
The LT8500ETJ#TRPBF implements a fully synchronous, clock-domain-separated architecture: SCKI (up to 50MHz) controls serial frame loading and correction multiplier computation, while PWMCK (up to 25MHz) independently clocks the 4096-step counter driving all 48 PWM outputs. Its 584-bit shift register supports command, update, correction, and status frames - including real-time OPENLED fault reporting and synchronization error detection.
Three 16-channel banks can be phase-shifted 120° via command register bit PHS, distributing switching transients across the PWM period. The internal correction multiplier applies 6-bit (64-step) scaling to each 12-bit channel value before latching into PWMRSYNC, enabling per-output brightness calibration without host-side computation.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Channels | 48 independent PWM outputs with individual 12-bit resolution (0–4095) |
| PWM Resolution | 12-bit (4096 steps); defines minimum duty cycle granularity (0.024% at 6.1kHz) |
| Correction Range | 6-bit (64 steps), ±50% adjustment per channel relative to programmed width |
| Max PWM Frequency | 6.1kHz at 25MHz PWMCK input; sets maximum refresh rate for flicker-free LED dimming |
| Serial Interface Speed | 50MHz SCKI; enables full 584-bit frame transfer in 11.7µs (85.5kHz frame rate) |
| Supply Voltage | 3.0V to 5.5V; compatible with standard logic I/O domains and mixed-voltage systems |
| Operating Temp | –40°C to +125°C junction; qualified for industrial and automotive display environments |
Pinout & Package
LT8500ETJ#TRPBF uses a 56-lead plastic TLA QFN package (6mm × 6mm × 0.78mm) with exposed thermal pad (Pin 57 = GND). The package supports high-density PCB layout and efficient thermal dissipation in LED driver modules.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| PWM[48:1] | 48-channel PWM output terminals | Open-drain CMOS outputs; drive external LED drivers (e.g., LT3595A) or FET gates directly |
| OPENLED (B11) | Diagnostic status input | Wired-OR open-collector input with 100kΩ internal pull-up; reports LED string open faults during self-test |
| SDO (A25) | Serial data output | Shift-register output; returns status frames (fault flags, COR registers, OLT/PHS/SYC bits) to host or next device |
| SCKI (B12) | Serial clock input | Primary timing reference for command/data loading; independent of PWMCK domain |
| VCC (A26) | Power supply | 3.0V–5.5V analog/digital supply; requires local 0.1µF bypass capacitor to exposed GND pad |
| SCKO (B13) | Serial clock output | Buffered SCKI pass-through; enables skew-balanced daisy-chaining in 5-wire topology |
| PWMCK (A27) | PWM clock input | Free-running counter clock (≤25MHz); determines PWM period and output frequency |
| SDI (B14) | Serial data input | Command/data input; accepts 584-bit frames (48×12-bit PWM + 48×6-bit COR + 8-bit CMD) |
| LDIBLANK (A28) | Dual-function control input | Rising edge latches frame; >50µs high asserts BLANK (resets all outputs), <5µs enables LDI only |
| GND (Pin 57) | Ground reference | Exposed thermal pad; must be soldered to PCB ground plane for thermal and electrical integrity |
Key Features
| Feature | Design Value |
|---|---|
| 48-channel 12-bit PWM generation | Enables precise, independent dimming control for large-format displays without external DACs or microcontroller overhead |
| Per-channel 6-bit correction (±50%) | Compensates for LED binning, trace resistance, and driver mismatch - eliminates manual calibration per channel |
| 50MHz cascadable 5-wire interface | Supports daisy-chained configurations of dozens of LT8500ETJ#TRPBF units with balanced SCKO/SDO skew and no global clock routing |
| Real-time diagnostic flags | Synchronization error (SYC) and open-LED (OLT/NOL[48:1]) reporting via status frame enable automated fault isolation in production test and field service |
| 120° phase-shifted bank operation | Reduces peak current demand and conducted EMI by staggering turn-on of three 16-channel groups across the PWM period |
Applications
| Large-Screen LCD Backlighting | Mono-/Full-Color LED Signage |
|---|---|
Use Scenario: Dynamic local dimming in 55"+ commercial LCD panels using edge-lit or direct-lit LED arrays. IC Role / Device Role / Timing Role: Primary PWM controller synchronizing backlight zones with video content; interfaces to FPGA or MCU over 50MHz serial bus. Use Value: 48 independent channels map directly to 48 backlight zones; 12-bit resolution enables smooth gradation without visible banding; phase-shift reduces power supply ripple. |
Use Scenario: Outdoor LED billboards requiring high-brightness, uniform color mixing across RGB pixel clusters. IC Role / Device Role / Timing Role: Centralized PWM generator driving multiple LT3595A LED drivers; handles per-pixel intensity scaling via correction registers. Use Value: Per-channel ±50% correction compensates for LED forward voltage variance and thermal drift; diagnostic OPENLED flag enables rapid open-string identification during maintenance. |
| Automated Test Equipment (ATE) | Industrial Motor Control |
Use Scenario: Programmable multi-channel intensity source for optical sensor calibration rigs. IC Role / Device Role / Timing Role: Precision PWM stimulus generator; receives frame commands from host PC via SPI-to-serial bridge. Use Value: 584-bit frame structure allows deterministic, low-jitter updates; 6.1kHz PWM frequency avoids audible noise while maintaining fast response for closed-loop feedback. |
Use Scenario: Multi-axis stepper/servo motor current profiling in CNC controllers and robotics. IC Role / Device Role / Timing Role: High-resolution PWM signal source for gate drivers; synchronized across axes using phase-shift mode. Use Value: 120° phase shift between banks distributes switching events across time, lowering RMS current stress on shared DC bus capacitors and reducing EMI in compact enclosures. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar PWM generator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LT8500ITJ#TRPBF | Identical functionality and pinout; guaranteed –40°C to +125°C operation across full temp range (vs. LT8500ETJ#TRPBF's design-assured range) | Suitable for extended-temperature industrial or automotive under-hood applications where full characterization is required | Select LT8500ITJ#TRPBF when full temperature-range testing and guaranteed specs are mandated by system qualification. |
| TLC5947IPWR | 24-channel, 12-bit PWM driver with dot-correction; 30MHz SPI interface; no phase-shift or OPENLED diagnostics | Limited to smaller displays or non-diagnostic LED arrays; lacks cascading skew balancing and sync-error detection | Choose TLC5947IPWR only for cost-sensitive, lower-channel-count designs where diagnostic capability and daisy-chain scalability are not required. |
Compared with LT8500ITJ#TRPBF, the LT8500ETJ#TRPBF offers identical performance but with design-assured (not fully tested) specs over –40°C to +125°C; compared with TLC5947IPWR, it doubles channel count, adds robust diagnostics and scalable cascadable timing - making it essential for large-format, mission-critical LED systems.
Availability
LT8500ETJ#TRPBF is available at Aetrix Electronics and suitable for large-screen LCD backlighting, full-color LED signage, and industrial motor control applications requiring stable component supply, long-term lifecycle support, and traceable sourcing.
Supply support for LT8500ETJ#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, Inc. is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving industrial, communications, automotive, and consumer markets.
The LT8500ETJ#TRPBF belongs to Analog Devices' LED lighting and precision timing product line, engineered specifically for high-channel-count, high-fidelity PWM control in demanding display and illumination systems.
FAQ
What is the maximum number of LT8500ETJ#TRPBF devices that can be daisy-chained reliably?
The LT8500ETJ#TRPBF supports robust daisy-chaining via its 5-wire interface (SCKI/SDI/SCKO/SDO/LDIBLANK) with internal skew balancing. While Analog Devices does not specify an absolute limit, application notes confirm stable operation with ≥12 devices in cascade at 50MHz SCKI when PCB layout follows controlled-impedance and parallel routing guidelines for SCKO/SDO pairs. Signal integrity - not device count - is the primary constraint.
Does the LT8500ETJ#TRPBF require external components for basic operation?
Yes - the LT8500ETJ#TRPBF requires a 0.1µF ceramic bypass capacitor between VCC (A26) and the exposed GND pad (Pin 57), plus appropriate series termination (typically 22–33Ω) on SDI and SCKI lines for impedance matching. No external oscillator or clock generator is needed, as both SCKI and PWMCK are driven externally, and OPENLED has an integrated 100kΩ pull-up.
How does the LT8500ETJ#TRPBF handle open-LED fault detection?
The LT8500ETJ#TRPBF detects open-LED faults via its OPENLED (B11) pin, which connects to wired-OR open-collector outputs of downstream LED drivers like the LT3595A. During a diagnostic self-test frame (CMD = 0x5X), it sequentially pulses each PWM output and samples OPENLED state per channel, reporting results as 48 individual NOL[48:1] bits in the status frame - enabling precise fault localization without additional sensors.
Can the LT8500ETJ#TRPBF operate with a 3.3V supply and 5V-tolerant logic inputs?
Yes - the LT8500ETJ#TRPBF operates from 3.0V to 5.5V and features 5V-tolerant digital inputs (SDI, SCKI, LDIBLANK, OPENLED, PWMCK) across its full supply range. At VCC = 3.3V, VIH is guaranteed ≥2.7V and VIL ≤0.6V, ensuring reliable interfacing with 3.3V microcontrollers and FPGAs without level-shifting circuitry.
What is the function of the LDIBLANK pin on the LT8500ETJ#TRPBF, and how is it used?
The LDIBLANK (A28) pin serves dual functions: a rising edge always acts as Latch Data In (LDI), terminating serial frames and executing commands; holding it high >50µs asserts BLANK, disabling all PWM outputs and resetting internal registers. To avoid unintended reset, pulse duration must stay below 5µs for LDI-only operation - critical for reliable frame synchronization in high-speed systems.
LT8500ETJ#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 56-VTLA Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Type:
- -
- Topology:
- -
- Internal Switch(s):
- -
- Number of Outputs:
- -
- Voltage - Supply (Min):
- -
- Voltage - Supply (Max):
- -
- Voltage - Output:
- -
- Current - Output / Channel:
- -
- Frequency:
- -
- Dimming:
- -
- Applications:
- -
- Operating Temperature:
- -40°C ~ 125°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 56-TLAQFN (6x6)
LT8500ETJ#TRPBF FAQ
1.How can I place an order for LT8500ETJ#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT8500ETJ#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 LT8500ETJ#TRPBF reliable?
The price and inventory of LT8500ETJ#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT8500ETJ#TRPBF is usually 5 days.
3.What payment methods are accepted for LT8500ETJ#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT8500ETJ#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT8500ETJ#TRPBF?
LT8500ETJ#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT8500ETJ#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 LT8500ETJ#TRPBF?
For technical support, including LT8500ETJ#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT8500ETJ#TRPBF requirements.
6.How does Aetrix verify that LT8500ETJ#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT8500ETJ#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 LT8500ETJ#TRPBF meets industry standards.
7.What is the process for return or replacement of LT8500ETJ#TRPBF?
All LT8500ETJ#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT8500ETJ#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 LT8500ETJ#TRPBF part is unused and in its original packaging.
Return procedure for LT8500ETJ#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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