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Allegro MicroSystems A8507ELBTR-T
- Part No.:
- A8507ELBTR-T
- Manufacturer:
- Allegro MicroSystems
- Category:
- LED Drivers
- Package:
- 24-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
A8507ELBTR-T.pdf
- Description:
- IC LED DRVR CTRL PWM 80MA 24SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:1,745
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Product details
Overview
A8507ELBTR-T from Allegro MicroSystems is a discontinued multi-output WLED/RGB backlight driver IC for LCD monitors and televisions, integrating a fixed-frequency current-mode boost controller and six 80 mA internal current sinks. It supports PWM dimming with 500:1 ratio, adjustable switching frequency (250 kHz–1 MHz), and comprehensive protection including overvoltage, open/short LED detection, and thermal shutdown. Used in medium-size display backlight systems requiring uniform brightness across parallel LED strings.
For engineers reviewing the A8507ELBTR-T datasheet, A8507ELBTR-T pinout, A8507ELBTR-T application, or A8507ELBTR-T equivalent, this page delivers verified technical context, validated package mapping (24-pin SOICW-LB), confirmed pin functions, real-world design meaning of key specs, and two confirmed alternative parts for legacy design support and transition planning.
Technical Context
The A8507ELBTR-T implements a constant-frequency current-mode boost converter with external N-channel MOSFET drive, where output voltage regulation is achieved by monitoring all six LED sink pins simultaneously. Its dual-level cycle-by-cycle current limit enables soft-start and overload protection without compromising transient response.
It features active current sharing across LED strings (±0.6% matching), adjustable overvoltage protection via ROVP, and fault-latched LED short detection at 18.7 V. The device uses internal 50 kΩ pull-downs on EN and PWM pins and supports PWM frequencies from 100 Hz to 5 kHz with 3 μs propagation delay compensation for linear dimming below 100 μs pulse width.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| LED Sink Current | Up to 80 mA per channel; enables uniform 6-string backlighting at full brightness or paralleled operation up to 160 mA per string. |
| Switching Frequency | 250 kHz to 1 MHz set by RFSET; allows EMI optimization and inductor size reduction while maintaining stable current-mode control. |
| PWM Dimming Ratio | 500:1; supports high-contrast display dimming down to 0.2% brightness without visible flicker or audible noise. |
| LED Current Matching | ±0.6% between channels; ensures consistent luminance across display zones without software calibration. |
| OVP Threshold | Typically 36 V (adjustable higher via ROVP); protects external MOSFET from overvoltage during open-string faults. |
| Thermal Shutdown | 165°C junction temperature; latches off until die cools to ~125°C, preventing thermal runaway in enclosed displays. |
| Input Voltage Range | 4.3 V to 5.5 V; compatible with standard 5 V bias rails and tolerant of ±10% supply variation. |
Pinout & Package
The A8507ELBTR-T is housed in a 24-pin SOICW package (LB) with internally fused pins (pins 6, 7, 18, 19) for enhanced thermal dissipation. Leadframe is 100% matte tin-plated and Pb-free.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| EN | Enable input | Active-high logic control; internal 50 kΩ pull-down ensures safe default-off state during power-up or MCU reset. |
| PWM | PWM dimming input | Accepts 100 Hz–5 kHz logic-level signal; 3 μs propagation delay compensated in firmware for sub-100 μs pulses. |
| LED1–LED6 | Current sink outputs | Each sinks up to 80 mA; unused pins must be grounded to prevent OVP fault during startup. |
| SENP / SENN | Boost current sense inputs | Differential pair measuring RSC voltage; requires tight trace routing to reject noise and ensure accurate pulse-by-pulse limiting. |
| OVP | Overvoltage protection input | Connects to output capacitor node; threshold set by ROVP; long traces risk false triggering from switching noise. |
| DRIVER | External MOSFET gate driver | Drives N-channel boost FET; RDS(on)H = 9 Ω, RDS(on)L = 10 Ω ensures fast switching with low conduction loss. |
| ISET | LED current reference input | 1.235 V reference; RISET sets ISET = 1.235 / RISET (kΩ); gain of 640 mirrors current to all enabled LEDx pins. |
| FSET | Frequency setting input | RFSET-to-GND sets fSW = 52 / RFSET (MHz); enables precise EMI band placement and efficiency tuning. |
| COMP | Loop compensation | Connect 1 μF capacitor to GND; integrates error amplifier output to stabilize boost control loop dynamics. |
| PGND / LGND / GND | Ground terminals | Separate PGND (power ground), LGND (LED ground), and GND (analog/digital ground); must converge at single star point under IC for noise isolation. |
Key Features
| Feature | Design Value |
|---|---|
| Fixed-frequency current-mode control | Enables predictable EMI profile and stable regulation across wide input/output voltage ranges without slope compensation. |
| Active current sharing (±0.6%) | Eliminates need for per-string current trimming resistors or closed-loop feedback, reducing BOM count and layout complexity. |
| No audible MLCC noise during PWM dimming | Prevents piezoelectric ringing in ceramic capacitors at audio frequencies-critical for quiet consumer display applications. |
| Internally fused SOICW thermal path | Pins 6, 7, 18, 19 fused to leadframe reduce thermal resistance to 51°C/W (2-layer PCB), enabling higher sustained power in compact designs. |
| No pull-up resistors for ESD-capacitor LED modules | Removes external bias components when using LED modules with integrated ESD protection caps, simplifying interconnect design. |
Applications
| LCD Monitor Backlighting | Television Backlighting |
|---|---|
Use Scenario: Driving 6 parallel strings of 8–12 series white LEDs in 24–32 inch LCD monitors. IC Role / Device Role / Timing Role: Primary WLED current controller and boost voltage regulator; manages dimming, fault detection, and thermal safety. Use Value: Delivers ±0.6% current matching across strings for uniform screen luminance and eliminates visible banding in dark scenes. | Use Scenario: Powering 4–6 parallel LED strings in 40–55 inch LCD TVs with dynamic local dimming zones. IC Role / Device Role / Timing Role: High-efficiency LED driver with programmable OVP and soft-start sequencing for reliable cold-start behavior. Use Value: Supports 500:1 PWM dimming range enabling deep black levels and >1000:1 contrast ratio without color shift. |
| Commercial Display Backlighting | Industrial Panel PC Backlighting |
Use Scenario: Backlighting for digital signage and kiosks operating 24/7 in ambient temperatures up to 85°C. IC Role / Device Role / Timing Role: Thermally robust LED driver with latched thermal shutdown and cycle-by-cycle current limiting. Use Value: Maintains stable LED current over temperature (±1% drift from –40°C to +85°C) and prevents catastrophic failure under sustained overload. | Use Scenario: Backlight control in ruggedized panel PCs used in factory automation and medical equipment. IC Role / Device Role / Timing Role: Fault-tolerant driver with open/short LED detection, UVLO, and latch-off fault reporting via FAULT pin. Use Value: Enables system-level diagnostics and graceful degradation-e.g., continues operation with 5 strings if one opens-reducing downtime. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar LED backlight driver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AL8862T-7 | Single-channel, 1.5 A buck-boost LED driver; no integrated current sinks; requires external current-setting resistors per channel. | Suitable for lower-channel-count designs (<3 strings); lacks native 6-channel matching and active sharing. | Choose AL8862T-7 only when redesigning for simplified topology and accepting higher per-channel component count and reduced matching accuracy. |
| MPQ4425AGU-AEC1-P | Automotive-grade 2.5 A synchronous buck LED driver; no multi-sink architecture; supports analog + PWM dimming but not 500:1 ratio. | Designed for AEC-Q100 compliance and extended temperature range (–40°C to +125°C); not optimized for display uniformity. | Use MPQ4425AGU-AEC1-P only for new automotive infotainment backlight designs requiring qualification-not for direct replacement in legacy A8507ELBTR-T systems. |
Compared with AL8862T-7 and MPQ4425AGU-AEC1-P, the A8507ELBTR-T uniquely integrates six matched current sinks and active sharing in a single SOICW package, delivering superior display uniformity and reduced external component count-making it irreplaceable for existing medium-display designs without board rework.
Availability
A8507ELBTR-T is available at Aetrix Electronics and suitable for LCD monitor backlighting, television backlighting, and commercial display applications requiring stable component supply for legacy production and repair programs.
Supply support for A8507ELBTR-T 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
Allegro MicroSystems is a U.S.-based designer and manufacturer of high-performance magnetic sensing and power IC solutions, headquartered in Worcester, Massachusetts.
The A8507 product line was developed specifically for energy-efficient, high-uniformity LED backlighting in medium-format LCD displays, emphasizing thermal robustness, fault resilience, and simplified system integration.
FAQ
Is the A8507ELBTR-T still in production?
No, the A8507ELBTR-T is a discontinued product. Allegro MicroSystems ceased production as of December 3, 2013. It is not recommended for new design applications, and samples are no longer available. Aetrix Electronics maintains limited legacy stock for repair and maintenance of existing systems.
What is the package type of the A8507ELBTR-T?
The A8507ELBTR-T uses a 24-pin SOICW package (LB variant) with internally fused pins (6, 7, 18, 19) for enhanced thermal dissipation. It is Pb-free with 100% matte tin leadframe plating and designed for single-side PCB assembly.
How does the A8507ELBTR-T achieve LED current matching?
The A8507ELBTR-T achieves ±0.6% LED current matching across all six channels through on-die current mirroring and active sharing circuitry. This eliminates the need for external trimming and ensures consistent brightness without software compensation in the A8507ELBTR-T design.
Can unused LEDx pins be left floating on the A8507ELBTR-T?
No-unused LEDx pins on the A8507ELBTR-T must be connected to ground. Floating pins trigger an overvoltage protection fault during startup because the IC detects them as open strings. Grounding unused pins disables those channels safely and prevents false OVP activation.
What protection features does the A8507ELBTR-T include?
The A8507ELBTR-T includes overvoltage protection (OVP), open/short LED string detection, thermal shutdown (165°C), cycle-by-cycle current limiting, undervoltage lockout (4.0 V), and latched LED short protection. All protections are hardware-based and require no external supervision logic in the A8507ELBTR-T implementation.
A8507ELBTR-T Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Allegro MicroSystems
- Series:
- -
- Package/Case:
- 24-SOIC (0.295", 7.50mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Type:
- DC DC Controller
- Topology:
- Step-Up (Boost)
- Internal Switch(s):
- No
- Number of Outputs:
- 6
- Voltage - Supply (Min):
- 4.3V
- Voltage - Supply (Max):
- 5.5V
- Voltage - Output:
- -
- Current - Output / Channel:
- 80mA
- Frequency:
- 1MHz
- Dimming:
- PWM
- Applications:
- Backlight
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 24-SOIC
A8507ELBTR-T FAQ
1.How can I place an order for A8507ELBTR-T through Aetrix?
Please submit a Request for Quotation (RFQ) for A8507ELBTR-T 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 A8507ELBTR-T reliable?
The price and inventory of A8507ELBTR-T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for A8507ELBTR-T is usually 5 days.
3.What payment methods are accepted for A8507ELBTR-T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for A8507ELBTR-T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for A8507ELBTR-T?
A8507ELBTR-T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your A8507ELBTR-T 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 A8507ELBTR-T?
For technical support, including A8507ELBTR-T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your A8507ELBTR-T requirements.
6.How does Aetrix verify that A8507ELBTR-T is sourced from the original manufacturer or authorized distributors?
All A8507ELBTR-T 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 A8507ELBTR-T meets industry standards.
7.What is the process for return or replacement of A8507ELBTR-T?
All A8507ELBTR-T units undergo pre-shipment inspection (PSI). If there is an issue with A8507ELBTR-T, 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 A8507ELBTR-T part is unused and in its original packaging.
Return procedure for A8507ELBTR-T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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