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Allegro MicroSystems A8515GLPTR-T
- Part No.:
- A8515GLPTR-T
- Manufacturer:
- Allegro MicroSystems
- Category:
- LED Drivers
- Package:
- 16-TSSOP (0.173", 4.40mm Width) Exposed Pad
- Datasheet:
-
A8515GLPTR-T.pdf
- Description:
- IC LED DRVR RGLTR PWM 16ETSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:4,823
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Product details
Overview
A8515GLPTR-T from Allegro MicroSystems is a discontinued wide-input, high-efficiency multi-output white LED driver IC for LCD backlighting. It integrates a current-mode boost converter with internal 60 V DMOS switch and two matched current sinks (120 mA per string), operates from 5–40 V input, delivers up to 24 LEDs (12 per string), and features 720 mV LED regulation voltage for minimal power loss in desktop FPDs and industrial monitors.
For engineers reviewing the A8515GLPTR-T datasheet, A8515GLPTR-T pinout, A8515GLPTR-T application, or A8515GLPTR-T equivalent, key selection considerations include its dual-string WLED sink architecture, 2.3 MHz sync-capable switching frequency, fault-tolerant protection suite (OVP, OTP, open/short LED detect), and TSSOP-16 LP package with exposed thermal pad - all critical for legacy display backlight design validation and obsolescence mitigation.
Technical Context
The A8515GLPTR-T implements adaptive output voltage regulation using equation VOUT = max(VLED1, VLED2) + 0.72 V, minimizing boost stage losses. Its current-mode control loop uses COMP pin compensation via RZ/CZ network and supports external synchronization up to 2.3 MHz on the FSET/SYNC pin.
Power-up includes mandatory LED pin short-to-GND detection (thresholds: <70 mV = halt, >325 mV = active), followed by soft-start with reduced switch current limit (700 mA) before transitioning to full 3.5 A cycle-by-cycle limiting. EN/PWM serves dual enable/dimming function with sub-500 ns LED turn-on/off delays.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 5–40 V - supports wide-range industrial supplies and automotive-derived rails without pre-regulation |
| Max LED Current per String | 120 mA - enables driving 12-series white LEDs at typical forward voltage (~3.2 V each) |
| LED Regulation Voltage | 720 mV - reduces conduction loss in current sinks, improving system efficiency by ~2–3% vs. higher-drop alternatives |
| Switching Frequency Range | 580 kHz–2.3 MHz - allows compact magnetics and EMI tuning via RFSET resistor or external SYNC signal |
| LED Accuracy & Matching | ±0.5% typical - ensures uniform brightness across dual strings without external calibration |
| Thermal Resistance (RθJA) | 34 °C/W on 4-layer PCB - requires exposed pad soldered with ≥8 thermal vias to ground plane for reliable 105°C operation |
| Protection Features | OVP (8.1 V threshold), OTP (165°C shutdown), open/short LED detect, cycle-by-cycle current limit - eliminates need for discrete fault monitoring circuitry |
Pinout & Package
The A8515GLPTR-T is housed in a 16-pin TSSOP package with exposed thermal pad (suffix LP), Pb-free with 100% matte-tin leadframe plating. The exposed pad must be connected to PCB ground plane via ≥8 thermal vias for thermal performance compliance.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VDD | Internal LDO output | Supplies bias for internal circuits; requires 0.1 µF decoupling to PGND |
| PGND | Power ground return | Low-impedance path for boost switch and LED sink currents; separate from AGND |
| OVP | Overvoltage sense input | Connects to VOUT via ROVP resistor to set 7.7–8.5 V OVP threshold |
| SW | Boost switch drain node | Drives external inductor; rated for 62 V transient, 3.5 A continuous switching |
| GATE | External PMOS driver output | Controls input disconnect FET with –6.7 V gate-source swing relative to VIN |
| VSENSE | Current-sense reference | Senses voltage drop across RSC; trip point is VIN – VSENSE = 180 mV |
| VIN | Main power input | Supplies boost stage and internal LDO; UVLO activates at 4.35 V rising |
| FAULT | Open-drain fault indicator | Pulled low during OVP, OTP, LED fault, or sync loss; requires 100 kΩ pull-up |
| COMP | Error amplifier output | Compensation node for stability tuning; connect RZ/CZ to AGND |
| APWM | Analog PWM dimming input | Digital signal (20–1000 kHz) that trims ISET current proportionally |
| EN/PWM | Enable & PWM dimming input | Logic-high enables device; PWM toggling dims LEDs with 0.5–500 ns response |
| FSET/SYNC | Frequency set/synchronization | Resistor sets fSW (580 kHz–2.3 MHz); accepts external clock up to 2.3 MHz |
| ISET | LED current programming | RISET resistor (e.g., 8.25 kΩ for 120 mA) sets full-scale LED current gain of 980 A/A |
| AGND | Analog ground reference | Reference for LED sinks and analog blocks; separate from PGND to avoid noise coupling |
| LED1 / LED2 | LED string cathode outputs | Each sinks up to 120 mA; paralleled for 240 mA total; short-detect enabled |
| PAD | Exposed thermal pad | Must be soldered to PCB ground plane with ≥8 thermal vias for RθJA = 34 °C/W |
Key Features
| Feature | Design Value |
|---|---|
| Adaptive VOUT regulation | Maintains minimum required output voltage (VLED_max + 0.72 V), reducing boost losses by up to 15% vs. fixed-output designs |
| Integrated 60 V DMOS switch | Eliminates external high-voltage MOSFET and associated gate drive complexity in boost stage |
| Single EN/PWM interface | Combines enable and PWM dimming functions, simplifying control logic and reducing GPIO count |
| LED pin short-to-GND detection | Halts power-up if LEDx voltage <70 mV, preventing uncontrolled current flow and potential damage |
| Sync-capable oscillator | Enables deterministic EMI reduction by locking multiple A8515GLPTR-T devices to common clock source |
| Internal bias supply | Allows single-supply operation (8–24 V VIN range) without external LDO for VDD generation |
Applications
| Desktop LCD Flat Panel Displays | Industrial Monitor Backlighting |
|---|---|
Use Scenario: Driving dual 10-LED strings in 24-inch desktop monitors with 120 mA per string and 200–1000 Hz PWM dimming. IC Role / Device Role / Timing Role: Primary WLED backlight controller providing regulated current, adaptive boost voltage, and fault-safe startup sequencing. Use Value: Enables uniform brightness, >85% peak efficiency at 12 V input, and automatic open/short LED detection without added components. | Use Scenario: Powering ruggedized 15-inch industrial displays operating from 24 VDC rails in factory automation panels. IC Role / Device Role / Timing Role: Fault-tolerant LED driver with overtemperature (165°C) and overvoltage (8.1 V) protection for extended thermal cycles. Use Value: Ensures backlight reliability under 105°C ambient conditions and withstands 40 V transients without latch-up or damage. |
| LCD TV Local Dimming Zones | Medical Imaging Display Backlights |
Use Scenario: Controlling individual LED zones in entry-level LCD TVs using two A8515GLPTR-T per zone for independent dimming. IC Role / Device Role / Timing Role: Dual-channel current sink enabling per-zone brightness control via synchronized EN/PWM signals. Use Value: Achieves <0.5% LED-to-LED matching across zones, critical for contrast consistency in segmented backlight architectures. | Use Scenario: Backlighting diagnostic-grade grayscale medical monitors requiring stable luminance over 8-hour shifts. IC Role / Device Role / Timing Role: Precision LED current regulator with ±0.5% accuracy and thermal derating support for continuous operation. Use Value: Maintains calibrated brightness levels across temperature (-40°C to 105°C) without recalibration, meeting DICOM GSDF requirements. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar LED driver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM3409QMHX/NOPB | Adjustable constant-current buck-boost LED driver; no integrated switch; requires external MOSFET and sense resistor | Supports higher output voltages (>60 V) but lacks built-in LED short/open detection and dual-sink integration | Preferred when designing for >40 V input or needing programmable fault thresholds beyond A8515GLPTR-T's fixed OVP/OTP points |
| TPS61165DRVR | Single-string 40 V boost LED driver with I²C interface; no dual-sink capability; lower max current (40 mA) | Offers digital dimming control and diagnostics via I²C, but cannot replace dual 120 mA strings without parallel ICs | Selected for space-constrained designs requiring telemetry and software-configurable dimming, not for high-current dual-string replacement |
Compared with LM3409QMHX/NOPB and TPS61165DRVR, the A8515GLPTR-T provides integrated dual 120 mA sinks, adaptive VOUT regulation, and comprehensive hardware-based fault protection - making it uniquely suited for cost-sensitive, high-reliability dual-string LCD backlighting where board area and BOM count are prioritized over digital configurability.
Availability
A85515GLPTR-T is available at Aetrix Electronics and suitable for legacy display repair, industrial monitor refurbishment, and medical equipment maintenance requiring stable component supply despite end-of-life status.
Supply support for A8515GLPTR-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 of high-performance magnetic sensing and power ICs, specializing in motion control, energy-efficient power conversion, and robust automotive-grade semiconductor solutions.
The A8515 product line was engineered specifically for high-efficiency, fault-resilient LCD backlighting in consumer and industrial flat-panel displays - emphasizing thermal robustness, integrated protection, and simplified system-level design.
FAQ
Is the A8515GLPTR-T still in production?
No, the A8515GLPTR-T is a discontinued product. Allegro MicroSystems has ceased production, and samples are no longer available. It should not be selected for new design applications. However, Aetrix Electronics maintains limited legacy inventory for repair, maintenance, and obsolescence mitigation of existing systems relying on the A8515GLPTR-T.
What is the maximum number of LEDs the A8515GLPTR-T can drive?
The A8515GLPTR-T can drive up to 24 white LEDs total - 12 LEDs per string across two independent current sinks (LED1 and LED2), each capable of 120 mA. When both sinks are paralleled, the device supports up to 240 mA total LED current, enabling configurations such as 24-series single-string operation with appropriate external circuitry.
Does the A8515GLPTR-T support analog dimming?
Yes, the A8515GLPTR-T supports analog dimming via the APWM pin, which accepts a digital PWM signal (20–1000 kHz) to proportionally adjust the ISET current and thus the LED current level. This provides an alternative to EN/PWM pin-based digital dimming and enables finer brightness control without visible flicker at low duty cycles.
What thermal management is required for the A8515GLPTR-T?
The A8515GLPTR-T requires connection of its exposed thermal pad to the PCB ground plane using at least eight thermal vias. On a 4-layer JEDEC-standard board, this achieves RθJA = 34 °C/W. Without proper pad grounding, junction temperature may exceed 150°C under full load, triggering thermal shutdown. Derating is necessary above 85°C ambient.
Can the A8515GLPTR-T synchronize with other switching regulators?
Yes, the A8515GLPTR-T supports external synchronization via its FSET/SYNC pin, accepting clock inputs up to 2.3 MHz. This allows multiple A8515GLPTR-T devices - or mixed Allegro LED drivers - to operate at identical frequencies, minimizing beat frequencies and simplifying EMI filter design in multi-backlight systems.
A8515GLPTR-T Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Allegro MicroSystems
- Series:
- -
- Package/Case:
- 16-TSSOP (0.173", 4.40mm Width) Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Type:
- DC DC Regulator
- Topology:
- Step-Up (Boost)
- Internal Switch(s):
- Yes
- Number of Outputs:
- 2
- Voltage - Supply (Min):
- 5V
- Voltage - Supply (Max):
- 40V
- Voltage - Output:
- -
- Current - Output / Channel:
- 120mA
- Frequency:
- 2.3MHz
- Dimming:
- Analog, PWM
- Applications:
- Backlight
- Operating Temperature:
- -40°C ~ 105°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-eTSSOP-EP
A8515GLPTR-T FAQ
1.How can I place an order for A8515GLPTR-T through Aetrix?
Please submit a Request for Quotation (RFQ) for A8515GLPTR-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 A8515GLPTR-T reliable?
The price and inventory of A8515GLPTR-T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for A8515GLPTR-T is usually 5 days.
3.What payment methods are accepted for A8515GLPTR-T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for A8515GLPTR-T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for A8515GLPTR-T?
A8515GLPTR-T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your A8515GLPTR-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 A8515GLPTR-T?
For technical support, including A8515GLPTR-T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your A8515GLPTR-T requirements.
6.How does Aetrix verify that A8515GLPTR-T is sourced from the original manufacturer or authorized distributors?
All A8515GLPTR-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 A8515GLPTR-T meets industry standards.
7.What is the process for return or replacement of A8515GLPTR-T?
All A8515GLPTR-T units undergo pre-shipment inspection (PSI). If there is an issue with A8515GLPTR-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 A8515GLPTR-T part is unused and in its original packaging.
Return procedure for A8515GLPTR-T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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