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Analog Devices Inc. LT8500EUHH#PBF
- Part No.:
- LT8500EUHH#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- LED Drivers
- Package:
- 56-WFQFN Exposed Pad
- Datasheet:
-
LT8500EUHH#PBF.pdf
- Description:
- IC PWM GENERATOR 56-QFN
- Quantity:
- Payment:
- Shipping:
Inventory:3,509
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Product details
Overview
LT8500EUHH#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% per-channel correction, 50MHz cascadable serial interface, and phase-shifted 16-channel bank operation to reduce EMI. It directly drives three LT3595A LED drivers in large-screen LCD and full-color LED signage applications.
For engineers reviewing the LT8500EUHH#PBF datasheet, LT8500EUHH#PBF pinout, LT8500EUHH#PBF application, or LT8500EUHH#PBF equivalent, key selection considerations include its 56-pin TLA QFN package, 6.1kHz max PWM frequency at 25MHz PWMCK, diagnostic open-LED/sync-error reporting, and 3V–5.5V supply compatibility with TTL/CMOS logic levels.
Technical Context
The LT8500EUHH#PBF implements a fully synchronous, cascadable 5-wire serial interface (SDI/SCKI/LDIBLANK/SDO/SCKO) with internal skew balancing and buffering, enabling reliable daisy-chaining of multiple devices at up to 50MHz SCKI. Its architecture includes a 584-bit shift register, 48 independent 12-bit PWM synchronization registers (PWMRSYNC), and a 6-bit per-channel correction multiplier that scales input data before latching.
Each of the 48 PWM outputs is generated by comparing its PWMRSYNC value against a free-running 12-bit PWMCK counter; output enable/disable is controlled via command frames, and phase-shift mode divides channels into three 16-channel banks operating 120° out-of-phase to suppress current spikes. Diagnostic flags-synchronization error (SYC) and open LED (OLT)-are embedded in status frames read back via SDO.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Channels | 48 independent PWM outputs with individual 12-bit resolution (4096 steps) |
| PWM Clock Frequency | Up to 25MHz PWMCK input → enables 6.1kHz max PWM output frequency (4096-cycle period) |
| Serial Interface Speed | 50MHz SCKI clock → supports 85.5kHz frame rate (584-bit frame + LDI) |
| Correction Range | 6-bit per-channel correction register (±50% of programmed PWM width) |
| Supply Voltage | 3.0V to 5.5V VCC - compatible with standard logic rails and industrial power domains |
| Diagnostic Flags | Synchronization error (SYC) and open LED (OLT) reported in every status frame via SDO |
| Phase Control | Configurable 120° phase shift across three 16-channel banks to reduce system-level EMI and inrush current |
Pinout & Package
LT8500EUHH#PBF is housed in 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 | Individually programmable CMOS outputs; each driven by comparison of PWMRSYNC[n] vs. PWMCK counter |
| OPENLED (B11) | Open-LED diagnostic input | Wired-OR fault reporting pin with internal 100kΩ pull-up; captures LED string open-circuit status on PWMCK edges |
| SDO (A25) | Serial data output | Shift-register output for status frames; cascades to next device or host controller |
| SCKI (B12) | Serial clock input | 50MHz timing reference for command frame shifting and correction calculation - independent of PWMCK |
| VCC (A26) | Power supply input | 3.0V–5.5V analog/digital supply; requires local bypass capacitor to GND |
| SCKO (B13) | Serial clock output | Buffered pass-through of SCKI; enables skew-balanced daisy-chain topology without global clock routing |
| PWMCK (A27) | PWM clock input | 25MHz max clock driving free-running 12-bit counter; defines PWM period and output timing granularity |
| SDI (B14) | Serial data input | Command/data input for update, correction, enable, and diagnostic frames |
| LDIBLANK (A28) | Dual-function latch/blank control | Rising edge latches command frame; >50µs high asserts BLANK (resets all PWM outputs) |
| 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 grayscale control across large LED arrays without external DACs or microcontroller overhead |
| Per-channel 6-bit correction | Compensates for LED forward-voltage variation and driver mismatch - improves uniformity in multi-string displays |
| 50MHz cascadable 5-wire interface | Eliminates global clock routing and reduces PCB layer count in multi-chip LED driver stacks |
| Integrated sync-error and open-LED diagnostics | Reduces system-level fault detection latency - no external monitoring circuitry required |
| 120° phase-shifted bank operation | Lowers peak input current and conducted EMI by distributing switching events across PWM period |
| Direct LT3595A driver compatibility | Optimized timing and signal mapping simplifies design of scalable 48+ channel LED driver systems |
Applications
| Large-Screen LCD Backlighting | Mono-/Full-Color LED Displays |
|---|---|
Use Scenario: Dynamic local dimming in 55″+ commercial LCD panels using segmented LED backlights. IC Role / Device Role / Timing Role: Primary PWM timing and channel control IC; synchronizes dimming zones with video frame updates via LDIBLANK-triggered frames. Use Value: Achieves >10,000:1 contrast ratio through 4096-step brightness control per zone, with phase-shifted banks minimizing power supply ripple. |
Use Scenario: High-fidelity RGB pixel control in indoor rental LED video walls (e.g., P2.5 pitch). IC Role / Device Role / Timing Role: Centralized PWM generator coordinating color balance and gamma correction across 48 parallel LED strings. Use Value: 6-bit per-channel correction compensates for binning variance between red/green/blue LEDs, ensuring consistent white point across display area. |
| LED Billboards & Signage | Industrial Motor/Actuator Control |
Use Scenario: Outdoor advertising displays requiring high reliability, wide temperature operation, and remote diagnostics. IC Role / Device Role / Timing Role: Fault-aware PWM controller interfacing with microcontroller over long cable runs using robust 5-wire daisy chain. Use Value: OPENLED self-test (CMD=0x5X) identifies open-circuit LED failures down to individual string level - enabling predictive maintenance without physical inspection. |
Use Scenario: Precision speed/torque control of small DC brushless motors in automated test equipment positioning stages. IC Role / Device Role / Timing Role: Multi-channel PWM source for gate drivers controlling H-bridge MOSFETs; uses phase-shift to smooth torque ripple. Use Value: 12-bit resolution enables <0.025% duty cycle granularity - critical for low-speed stability and repeatable positioning accuracy. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar 48-channel PWM generator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TLC5947IPWPR | 24-channel, 12-bit PWM with dot-correction; 30MHz SPI interface; no built-in open-LED diagnostics or phase-shift capability | Requires two devices for 48 channels; lacks integrated sync-error flag and cascading skew compensation | Choose when lower channel count suffices and cost-per-channel is prioritized over diagnostic depth |
| IS31FL3731-QFLS4-TR | 28-channel, 12-bit PWM with auto-breathing; I²C interface; integrated LED matrix scan logic - not pin-compatible | Designed for direct LED matrix drive; no support for external LED drivers like LT3595A | Prefer for compact, low-pin-count LED matrix applications where serial daisy-chaining is unnecessary |
Compared with TLC5947IPWPR and IS31FL3731-QFLS4-TR, the LT8500EUHH#PBF uniquely combines 48-channel density, 50MHz cascadable interface with skew balancing, open-LED diagnostics, and configurable 120° phase shift - making it the only option validated for high-reliability, large-scale LED backlight and signage systems requiring synchronized multi-device operation.
Availability
LT8500EUHH#PBF 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, extended temperature operation, and long-term production continuity.
Supply support for LT8500EUHH#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, Inc. is a global semiconductor leader specializing in high-performance analog, mixed-signal, and digital signal processing technologies for precision instrumentation, industrial automation, and communications infrastructure.
The LT8500EUHH#PBF belongs to Analog Devices' LED driver and timing control product line, engineered specifically for high-channel-count, low-noise, diagnostic-capable PWM generation in professional display and lighting systems.
FAQ
What is the maximum PWM output frequency supported by the LT8500EUHH#PBF?
The LT8500EUHH#PBF achieves a maximum PWM output frequency of 6.1kHz when driven by a 25MHz PWMCK input signal. This corresponds to a full 4096-cycle period (2¹²), and the frequency scales linearly with PWMCK - e.g., 12.5MHz PWMCK yields ~3.05kHz. The LT8500EUHH#PBF does not support variable-frequency PWM per channel; all outputs share the same PWMCK-derived timing base.
How does the LT8500EUHH#PBF handle open-LED fault detection?
The LT8500EUHH#PBF monitors the OPENLED (B11) pin - an open-collector input typically tied to wired-OR outputs of LT3595A drivers. It reports fault status in two modes: continuous monitoring (status frame LSBs reflect real-time pin state), and diagnostic self-test (CMD=0x5X), which sequentially pulses each PWM output while sampling OPENLED to identify the exact faulty string. Both methods are reported in the status frame shifted out on SDO.
Can the LT8500EUHH#PBF be cascaded with other LT8500 devices, and what is the recommended topology?
Yes, the LT8500EUHH#PBF supports robust daisy-chaining via its 5-wire interface (SDI/SCKI/LDIBLANK/SDO/SCKO). Analog Devices recommends the novel 5-wire topology - where SCKO from one device clocks the next - to eliminate global SCKI routing, balance inter-device skew, and enable longer chains at 50MHz. The LT8500EUHH#PBF's internal skew compensation ensures timing compliance across ≥10 devices in this configuration.
What is the function of the LDIBLANK pin on the LT8500EUHH#PBF, and how do LDI and BLANK modes differ?
The LDIBLANK (A28) pin on the LT8500EUHH#PBF serves dual functions: Latch Data In (LDI) and BLANK. A rising edge always triggers LDI - ending the current command frame and executing its CMD field. Holding LDIBLANK high >50µs asserts BLANK, which immediately disables all 48 PWM outputs and resets internal registers. To avoid unintended reset, pulse duration must stay below 5µs for pure LDI operation - the window between 5µs and 50µs is undefined.
Does the LT8500EUHH#PBF require external components for basic operation?
Yes, the LT8500EUHH#PBF requires a minimum of two external components: a 0.1µF ceramic bypass capacitor between VCC (A26) and GND (Pin 57), and a series resistor (typically 33Ω) on the SCKI line to dampen ringing in high-speed layouts. The OPENLED pin has an internal 100kΩ pull-up, so no external resistor is needed unless interfacing with non-5V-tolerant drivers. All other functionality is self-contained within the LT8500EUHH#PBF die.
LT8500EUHH#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)
LT8500EUHH#PBF FAQ
1.How can I place an order for LT8500EUHH#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT8500EUHH#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 LT8500EUHH#PBF reliable?
The price and inventory of LT8500EUHH#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT8500EUHH#PBF is usually 5 days.
3.What payment methods are accepted for LT8500EUHH#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT8500EUHH#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT8500EUHH#PBF?
LT8500EUHH#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT8500EUHH#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 LT8500EUHH#PBF?
For technical support, including LT8500EUHH#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT8500EUHH#PBF requirements.
6.How does Aetrix verify that LT8500EUHH#PBF is sourced from the original manufacturer or authorized distributors?
All LT8500EUHH#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 LT8500EUHH#PBF meets industry standards.
7.What is the process for return or replacement of LT8500EUHH#PBF?
All LT8500EUHH#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT8500EUHH#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 LT8500EUHH#PBF part is unused and in its original packaging.
Return procedure for LT8500EUHH#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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