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Analog Devices Inc. LT8500ITJ#TRPBF
- Part No.:
- LT8500ITJ#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- LED Drivers
- Package:
- 56-VTLA Exposed Pad
- Datasheet:
-
LT8500ITJ#TRPBF.pdf
- Description:
- IC PWM GENERATOR 56-TLAQFN
- Quantity:
- Payment:
- Shipping:
Inventory:3,129
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Product details
Overview
LT8500ITJ#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% 6-bit correction per channel, operates from 3.0V to 5.5V, and supports a 50MHz cascadable serial interface. Its primary circuit role is synchronized digital PWM signal generation for driving three LT3595A LED drivers in large-screen LCD or full-color LED displays.
For engineers reviewing the LT8500ITJ#TRPBF datasheet, LT8500ITJ#TRPBF pinout, LT8500ITJ#TRPBF application, or LT8500ITJ#TRPBF equivalent, key selection considerations include its 56-pin TLA QFN package, phase-shifted 16-channel bank operation (reducing EMI), diagnostic open-LED/sync-error reporting via status frame, and direct compatibility with LT3595A driver cascades.
Technical Context
The LT8500ITJ#TRPBF implements a 584-bit shift register architecture with dual-clock domains: 50MHz SCKI for command/status framing and independent 25MHz PWMCK for output timing. Each of the 48 PWM channels uses a dedicated 12-bit PWMRSYNC register compared against a free-running PWMCK counter to generate precise duty cycles.
It features on-chip correction multiplication (6-bit × 12-bit) with programmable enable/disable, synchronous/asynchronous update modes, and dual-function LDIBLANK (latch data input + global blank/reset). Diagnostic flags-synchronization error (SYC) and open LED (OLT)-are embedded in every status frame and validated per channel during self-test mode.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Channels | 48 independent PWM outputs with individual 12-bit resolution (0–4095) |
| PWM Frequency | Up to 6.1kHz at 25MHz PWMCK (4096-cycle period); adjustable via external clock |
| Correction Range | ±50% per channel via 6-bit register (0–63), applied as multiplicative offset before PWMRSYNC load |
| Serial Interface | 50MHz TTL/CMOS cascadable 5-wire interface (SDI/SCKI/LDIBLANK/SDO/SCKO) with skew-balancing |
| Supply Voltage | 3.0V to 5.5V - supports direct interfacing with 3.3V and 5V logic systems without level shifting |
| Operating Temp | –40°C to +125°C junction - qualified for industrial and automotive display subsystems |
| Package | 56-lead TLA QFN (6mm × 6mm × 0.78mm) with exposed GND pad - optimized for thermal dissipation in LED driver stacks |
Pinout & Package
LT8500ITJ#TRPBF is housed in a 56-lead plastic TLA QFN package (6mm × 6mm, 0.78mm height) with exposed GND pad (Pin 57) requiring PCB soldering for thermal and electrical integrity.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| PWM[48:1] | 48-channel PWM output terminals | Open-drain compatible; each drives external LED string or LT3595A EN/CTRL input; logic-high when PWMCK count < PWMRSYNC value |
| OPENLED (B11) | Diagnostic status input | Wired-OR fault reporting pin with internal 100kΩ pull-up; captures open-LED state per PWM cycle during self-test; feeds status frame LSBs |
| SDO (A25) | Serial data output | Shift-register output; returns status frame (584 bits) synchronously with SCKO; cascades to next device's SDI |
| SCKI (B12) | Serial clock input | 50MHz master clock for command framing and correction multiplier timing; independent of PWMCK domain |
| VCC (A26) | Power supply | 3.0V–5.5V analog/digital rail; requires local 1µF ceramic bypass to exposed GND pad (Pin 57) |
| SCKO (B13) | Serial clock output | Buffered, skew-compensated replica of SCKI; enables daisy-chain clock distribution without global routing |
| PWMCK (A27) | PWM timing clock input | Up to 25MHz clock source for PWM counter; determines fundamental frequency and resolution granularity |
| SDI (B14) | Serial data input | Receives 584-bit command frames (update/correction/enable); MSB-first, channel-major order |
| LDIBLANK (A28) | Dual-function control input | Rising edge latches command frame; >50µs high asserts BLANK (resets all PWM outputs and shift register) |
| GND (57) | Ground reference | Exposed thermal pad - must be soldered to PCB ground plane for thermal management and noise immunity |
Key Features
| Feature | Design Value |
|---|---|
| Three-phase bank control | Enables 120° phase shift across three 16-channel groups to reduce peak current and EMI in large LED arrays |
| Integrated correction multiplier | Applies per-channel 6-bit scaling (±50%) to 12-bit PWM values before loading into PWMRSYNC registers |
| Real-time diagnostic feedback | Embedded sync-error (SYC) and open-LED (OLT) flags reported in every status frame - no external monitoring required |
| Cascadable 5-wire interface | Eliminates global SCKI routing; SCKO/SDO skew balancing allows >10-device chains at 50MHz without buffer insertion |
| Self-test capability | Diagnostic command (CMD = 0x5X) pulses each PWM output sequentially to isolate open-LED faults in multi-string configurations |
Applications
| Large-Screen LCD Backlighting | Mono-/Full-Color LED Displays |
|---|---|
|
Use Scenario: Dynamic local dimming in 4K/UHD LCD TVs and commercial signage using 48-zone LED backlight arrays. IC Role / Device Role / Timing Role: Primary PWM timing controller generating synchronized, phase-shifted dimming signals for three LT3595A LED drivers. Use Value: Enables 12-bit grayscale precision and reduced switching noise via 120° bank phasing - critical for contrast preservation and EMI compliance. |
Use Scenario: Pixel-level intensity control in outdoor LED billboards with mixed-color (RGB) modules and long cable runs. IC Role / Device Role / Timing Role: Centralized PWM generator interfacing with FPGA host controller via cascadable 5-wire serial bus. Use Value: 50MHz interface sustains >85kHz frame rate (11.7µs/frame), supporting real-time video refresh without visible flicker or latency. |
| Industrial LED Signage | Automated Test Equipment (ATE) |
|
Use Scenario: High-reliability indoor/outdoor signage operating continuously at –40°C to +125°C ambient. IC Role / Device Role / Timing Role: Robust PWM engine with built-in open-LED diagnostics and sync-error detection for predictive maintenance. Use Value: On-chip OPENLED self-test (CMD = 0x5X) identifies failed LED strings without external sensors - reducing field service cost. |
Use Scenario: Programmable stimulus generation for LED driver IC validation across voltage, temperature, and timing corners. IC Role / Device Role / Timing Role: Precision waveform source providing calibrated, independently adjustable PWM signals to DUT inputs. Use Value: 12-bit resolution and 6-bit correction allow sub-0.1% duty cycle repeatability - essential for parametric test accuracy. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar PWM generator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LT8500ETJ#TRPBF | Same silicon, rated for 0°C to 125°C junction - lacks guaranteed performance below 0°C | Suitable for commercial-grade displays but not industrial/automotive environments requiring –40°C operation | Select LT8500ITJ#TRPBF when full –40°C to +125°C qualification is mandated by system spec or safety standard. |
| TLC5947IPWPR | 24-channel, 12-bit PWM driver with integrated constant-current sinks; no cascading or phase-shift capability | Targeted at low-channel-count RGB LED modules - lacks diagnostic flags, OPENLED interface, or LT3595A integration | Choose TLC5947IPWPR only for space-constrained, single-chip 24-output designs where cascading and fault reporting are unnecessary. |
Compared with LT8500ETJ#TRPBF, the LT8500ITJ#TRPBF guarantees full –40°C to +125°C operation and includes extended characterization for industrial reliability; versus TLC5947IPWPR, it provides double the channel count, cascadability, and system-level diagnostics - making it uniquely suited for large-scale LED display infrastructure.
Availability
LT8500ITJ#TRPBF is available at Aetrix Electronics and suitable for large-screen LCD backlighting, mono-/full-color LED displays, and industrial LED signage requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for LT8500ITJ#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. (ADI) is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving industrial, automotive, communications, and healthcare markets.
The LT8500ITJ#TRPBF belongs to ADI's LED lighting and display controller product line, engineered specifically for high-channel-count, high-resolution dynamic backlighting and multi-color LED array control with integrated diagnostics and noise reduction.
FAQ
What is the maximum PWM frequency supported by the LT8500ITJ#TRPBF?
The LT8500ITJ#TRPBF achieves up to 6.1kHz PWM frequency when driven by a 25MHz PWMCK clock (4096-cycle period). The actual output frequency scales linearly with the applied PWMCK frequency - for example, a 12.5MHz input yields ~3.05kHz. This relationship is fixed by the 12-bit counter depth and cannot be altered via configuration.
How does the LT8500ITJ#TRPBF handle open-LED fault detection?
The LT8500ITJ#TRPBF monitors the OPENLED pin (B11) - which connects to wired-OR outputs of LT3595A drivers - and reports fault status in two modes. During normal operation, it captures the pin state once per frame and duplicates it across all 48 status bits. In diagnostic self-test mode (CMD = 0x5X), it pulses each PWM output individually and records OPENLED state per channel, enabling precise fault localization.
Can the LT8500ITJ#TRPBF be cascaded with other devices, and what topology is recommended?
Yes, the LT8500ITJ#TRPBF supports robust cascading via its 5-wire interface (SDI/SCKI/LDIBLANK/SDO/SCKO). The recommended topology uses SCKO and SDO to drive the next device's SCKI and SDI, eliminating global clock routing and enabling >10-device chains at 50MHz. For low-speed or short-chain applications, the 4-wire variant (ignoring SCKO) is also supported.
What is the function of the LDIBLANK pin on the LT8500ITJ#TRPBF?
The LDIBLANK pin (A28) serves two distinct functions based on pulse width: a rising edge ≤5µs wide acts as LDI (latch data input), terminating command frames and executing commands; a pulse >50µs wide asserts BLANK, disabling all 48 PWM outputs and resetting internal registers. Pulses between 5µs and 50µs cause undefined behavior and must be avoided.
Does the LT8500ITJ#TRPBF require external components for basic operation?
Yes - the LT8500ITJ#TRPBF requires a minimum 1µF ceramic capacitor between VCC (A26) and the exposed GND pad (Pin 57) for power supply decoupling. No external resistors or timing components are needed for core PWM or serial interface functionality; all timing is derived from the supplied SCKI and PWMCK clocks.
LT8500ITJ#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)
LT8500ITJ#TRPBF FAQ
1.How can I place an order for LT8500ITJ#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT8500ITJ#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 LT8500ITJ#TRPBF reliable?
The price and inventory of LT8500ITJ#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT8500ITJ#TRPBF is usually 5 days.
3.What payment methods are accepted for LT8500ITJ#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT8500ITJ#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT8500ITJ#TRPBF?
LT8500ITJ#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT8500ITJ#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 LT8500ITJ#TRPBF?
For technical support, including LT8500ITJ#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT8500ITJ#TRPBF requirements.
6.How does Aetrix verify that LT8500ITJ#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT8500ITJ#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 LT8500ITJ#TRPBF meets industry standards.
7.What is the process for return or replacement of LT8500ITJ#TRPBF?
All LT8500ITJ#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT8500ITJ#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 LT8500ITJ#TRPBF part is unused and in its original packaging.
Return procedure for LT8500ITJ#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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