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Analog Devices Inc. LT8500IUHH#PBF
- Part No.:
- LT8500IUHH#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- LED Drivers
- Package:
- 56-WFQFN Exposed Pad
- Datasheet:
-
LT8500IUHH#PBF.pdf
- Description:
- IC PWM GENERATOR 56-QFN
- Quantity:
- Payment:
- Shipping:
Inventory:3,222
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Product details
Overview
LT8500IUHH#PBF 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, supports 50MHz TTL/CMOS serial interface, and operates from 3V to 5.5V supply. Its phase-shift capability reduces EMI in large-screen LCD dynamic backlighting systems.
For engineers reviewing the LT8500IUHH#PBF datasheet, LT8500IUHH#PBF pinout, LT8500IUHH#PBF application, or LT8500IUHH#PBF equivalent, key selection criteria include cascadable 5-wire serial timing (SCKI/SDO/SCKO/LDIBLANK/SDI), diagnostic open-LED flag reporting, synchronous/asynchronous update modes, and direct compatibility with LT3595A LED drivers.
Technical Context
The LT8500IUHH#PBF implements a 584-bit shift register architecture with three 16-channel banks configurable for 120° phase-shifted operation, reducing switching noise in multi-LED systems. Its dual-clock domain separates 50MHz SCKI (serial control) from 25MHz PWMCK (output timing), enabling independent frame loading and PWM generation.
Diagnostic functionality integrates real-time OPENLED status capture-either continuously or via self-test mode-and embeds synchronization error (SYC), phase-shift (PHS), and correction disable (CRD) flags into every status frame. The internal 100kΩ pull-up on OPENLED enables wired-OR fault detection with LT3595A drivers without external components.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Channels | 48 independent PWM outputs with individual 12-bit resolution (4096 steps) |
| PWM Clock Max | 25MHz PWMCK input supports up to 6.1kHz output frequency (4096-cycle period) |
| Serial Interface | 50MHz TTL/CMOS 5-wire interface (SDI/SCKI/LDIBLANK/SDO/SCKO) with skew-balanced buffering |
| Correction Range | 6-bit (64-step) per-channel correction register enabling ±50% PWM width adjustment |
| Supply Voltage | 3.0V to 5.5V operation with rail-to-rail digital I/O compatibility |
| Operating Temp | –40°C to +125°C junction temperature range, qualified for industrial environments |
| Package | 56-pin TLA QFN (6mm × 6mm × 0.78mm) with exposed GND pad for thermal management |
Pinout & Package
LT8500IUHH#PBF uses 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 outputs; each driven by comparison of PWMRSYNC register value against free-running PWMCK counter |
| OPENLED (B11) | Diagnostic input | Wired-OR fault reporting pin with internal 100kΩ pull-up; captures open-LED status per PWM cycle or during self-test mode |
| SDO (A25) | Serial data output | Shift register output cascading status frames (584 bits) to downstream devices or host controller |
| SCKI (B12) | Serial clock input | 50MHz master clock for command frame shifting and correction multiplier calculation; independent of PWMCK |
| VCC (A26) | Power supply | 3.0V–5.5V analog/digital supply requiring local bypass capacitor to GND |
| SCKO (B13) | Serial clock output | Buffered pass-through of SCKI for daisy-chained topology; enables skew-balanced cascading without global clock routing |
| PWMCK (A27) | PWM timing clock input | 25MHz max clock defining PWM period (4096 cycles); drives internal counter for all 48 channels |
| SDI (B14) | Serial data input | Command frame input (584 bits) containing 48×12-bit PWM values + 8-bit command field |
| LDIBLANK (A28) | Dual-function control input | Rising edge latches command frame; >50µs high pulse blanks all outputs and resets chip; >5µs but <50µs enables LDI only |
| GND (Pin 57) | Ground reference | Exposed thermal pad serving as primary ground connection; must be soldered to PCB plane |
Key Features
| Feature | Design Value |
|---|---|
| 48-channel phase-shifted PWM | Three 16-channel banks configurable for 120° out-of-phase operation to reduce peak current and EMI |
| Integrated diagnostic flags | Synchronization error (SYC) and open-LED (OLT) status reported in every 584-bit status frame |
| Programmable correction multiplier | 6-bit per-channel correction register scales 12-bit PWM data with ±50% linear adjustment before storage |
| Cascadable 5-wire interface | Eliminates global SCKI routing; SCKO/SDO skew balancing enables >10-device chains at 50MHz |
| Self-test diagnostic mode | Command-triggered sequential PWM pulsing (64 cycles/channel) identifies open-LED faults per string when used with LT3595A |
Applications
| Large-Screen LCD Backlighting | Mono-/Full-Color LED Displays |
|---|---|
Use Scenario: Dynamic local dimming in 4K/UHD TV backlights using 48 individually controlled LED zones. IC Role / Device Role / Timing Role: Primary PWM generator synchronizing brightness across multiple LED driver ICs (e.g., LT3595A) with phase-shifted timing to minimize power supply ripple. Use Value: Enables 12-bit grayscale depth and flicker-free dimming down to 0.02% duty cycle while maintaining <1% inter-zone intensity variation. |
Use Scenario: Pixel-level intensity control in outdoor LED billboards requiring high reliability and fault visibility. IC Role / Device Role / Timing Role: Centralized PWM controller interfacing with microcontroller over 50MHz serial bus; reports open-LED faults via OPENLED pin and status frame. Use Value: Reduces system-level diagnostics time by 70% through per-channel fault identification without external sensing circuitry. |
| Industrial Motor Control | Automated Test Equipment |
Use Scenario: Precision speed/torque modulation in multi-axis servo drives using PWM-modulated gate drivers. IC Role / Device Role / Timing Role: High-resolution timing source generating synchronized PWM waveforms across 48 IGBT/MOSFET gate drivers with jitter <2ns. Use Value: Achieves <0.1% speed regulation accuracy under variable load by eliminating inter-channel timing skew via phase-shifted banks. |
Use Scenario: Stimulus generation for LED-based optical sensor calibration systems requiring repeatable, calibrated light pulses. IC Role / Device Role / Timing Role: Programmable waveform engine delivering precise 12-bit intensity steps and 6.1kHz repetition rate with sub-microsecond timing stability. Use Value: Eliminates need for external DACs or FPGA logic; reduces BOM count by 3 components per channel versus discrete solutions. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar PWM generator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TLC5947IPWPR | 24-channel, 12-bit PWM with dot-correction; no phase-shift or OPENLED diagnostic; 30MHz SPI interface | Lacks cascadable 5-wire topology and integrated open-LED fault reporting; requires external fault detection circuitry | Choose for cost-sensitive, lower-channel-count designs where diagnostic reporting is handled externally |
| IS31FL3731-QFLS4-TR | 28-channel, 8-bit PWM with auto-breathing; I²C interface; no correction register or PWMCK clock input | Fixed 8-bit resolution limits grayscale depth; lacks programmable correction and phase-shift capability | Choose for simple RGB LED matrix control where 12-bit precision and EMI reduction are not required |
Compared with TLC5947IPWPR and IS31FL3731-QFLS4-TR, the LT8500IUHH#PBF uniquely combines 48-channel 12-bit resolution, per-channel correction, phase-shifted operation, and embedded OPENLED diagnostics-making it the only option supporting full-system fault isolation in large-scale LED driver stacks without additional ICs.
Availability
LT8500IUHH#PBF is available at Aetrix Electronics and suitable for large-screen LCD backlighting, mono-/full-color LED displays, LED billboards and signboards, industrial motor control, and automated test equipment requiring stable component supply across extended temperature ranges.
Supply support for LT8500IUHH#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 is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving industrial, automotive, communications, and healthcare markets.
The LT8500IUHH#PBF belongs to Analog Devices' LED lighting and display controller product line, engineered specifically for high-channel-count, high-resolution PWM applications demanding low EMI, robust diagnostics, and seamless cascading in large-format visual systems.
FAQ
What is the maximum PWM frequency supported by the LT8500IUHH#PBF?
The LT8500IUHH#PBF supports a maximum PWM frequency of 6.1kHz when driven by a 25MHz PWMCK clock signal, corresponding to a 4096-cycle period. This frequency is fixed by the 12-bit counter depth and PWMCK input rate; users cannot exceed this limit without modifying the internal counter architecture, which is not user-configurable.
How does the LT8500IUHH#PBF handle open-LED fault detection?
The LT8500IUHH#PBF detects open-LED faults via its OPENLED pin, which connects to wired-OR outputs of companion LED drivers like the LT3595A. During self-test mode (CMD = 0x5X), it sequentially pulses each PWM output and samples OPENLED state per channel, reporting results in the status frame's NOL[48:1] bits-enabling precise fault localization without external circuitry.
Can the LT8500IUHH#PBF be cascaded with more than two devices?
Yes-the LT8500IUHH#PBF supports daisy-chaining via its 5-wire interface (SDI/SCKI/LDIBLANK/SDO/SCKO). Skew-balanced SCKO/SDO outputs enable reliable cascading of over 10 devices at 50MHz, provided PCB routing maintains matched trace lengths between SCKO and SDO to adjacent device's SCKI and SDI pins.
What is the function of the LDIBLANK pin on the LT8500IUHH#PBF?
The LDIBLANK pin on the LT8500IUHH#PBF serves dual functions: a rising edge triggers LDI (latch data input) to end command frames and execute commands, while a high pulse exceeding 50µs asserts BLANK-immediately disabling all 48 PWM outputs and resetting internal registers. Pulses between 5µs and 50µs activate only LDI, avoiding unintended reset.
Does the LT8500IUHH#PBF require external components for basic operation?
The LT8500IUHH#PBF requires only a local 0.1µF ceramic bypass capacitor on VCC to GND for stable operation. No external pull-ups, level shifters, or timing resistors are needed-the OPENLED pin includes an internal 100kΩ pull-up, and all digital I/Os are TTL/CMOS compatible across 3V–5.5V supply.
LT8500IUHH#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 56-WFQFN Exposed Pad
- Packaging:
- Tube
- Product Status:
- Obsolete
- Type:
- PWM Generator
- 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-QFN (5x9)
LT8500IUHH#PBF FAQ
1.How can I place an order for LT8500IUHH#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT8500IUHH#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 LT8500IUHH#PBF reliable?
The price and inventory of LT8500IUHH#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT8500IUHH#PBF is usually 5 days.
3.What payment methods are accepted for LT8500IUHH#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT8500IUHH#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT8500IUHH#PBF?
LT8500IUHH#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT8500IUHH#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 LT8500IUHH#PBF?
For technical support, including LT8500IUHH#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT8500IUHH#PBF requirements.
6.How does Aetrix verify that LT8500IUHH#PBF is sourced from the original manufacturer or authorized distributors?
All LT8500IUHH#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 LT8500IUHH#PBF meets industry standards.
7.What is the process for return or replacement of LT8500IUHH#PBF?
All LT8500IUHH#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT8500IUHH#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 LT8500IUHH#PBF part is unused and in its original packaging.
Return procedure for LT8500IUHH#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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