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Allegro MicroSystems A8512ELPTR-T
- Part No.:
- A8512ELPTR-T
- Manufacturer:
- Allegro MicroSystems
- Category:
- LED Drivers
- Package:
- 24-TSSOP (0.173", 4.40mm Width) Exposed Pad
- Datasheet:
-
A8512ELPTR-T.pdf
- Description:
- IC LED DRIVER CTRLR PWM 24TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:3,226
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Product details
Overview
A8512ELPTR-T from Allegro MicroSystems is a discontinued 24-pin TSSOP LED backlight driver IC for LCD monitors and televisions, integrating a programmable-frequency (300 kHz–1 MHz) boost controller with six matched current sinks, 8–24 V input operation, ±0.6% LED current matching, and active open/short LED string protection. It supports PWM dimming up to 5 kHz with 500:1 current ratio and enables master/slave parallel configuration for up to 36 LED strings.
For engineers reviewing the A8512ELPTR-T datasheet, A8512ELPTR-T pinout, A8512ELPTR-T application, or A8512ELPTR-T equivalent, this page delivers verified technical context, thermal performance data (RθJA = 28 °C/W), real-world fault behavior (OVP latch, short-detect shutdown), and validated alternative part selection guidance - all specific to the A8512ELPTR-T TSSOP package variant.
Technical Context
The A8512ELPTR-T implements fixed-frequency current-mode boost control with external MOSFET gate drive (7 V regulated), dual-level cycle-by-cycle current limiting for soft start and overload protection, and simultaneous multi-string regulation via shared sense feedback across all six LED sinks. Its ISET-based current setting (gain = 640, VISET = 1.235 V) enables precise per-channel current programming from 41–190 µA ISET range.
It features active current sharing between LED strings (±0.6% matching), programmable overvoltage protection (19.5–21.0 V base threshold), thermal shutdown at 165 °C, and three independent fault detection mechanisms: open LED (OVP-triggered removal), shorted LED (25 V detect threshold), and overtemperature. All protections are latched and require EN reset.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 8–24 V - supports wide-input industrial and consumer display power rails without external pre-regulation. |
| Switching Frequency | 300 kHz–1 MHz - adjustable via RFSET resistor; higher frequencies reduce inductor size but increase switching loss. |
| LED Current Accuracy | ±0.6% - ensures uniform brightness across all six channels under varying temperature and load conditions. |
| Thermal Resistance | RθJA = 28 °C/W - measured on 4-layer JEDEC PCB; enables 1.2 W dissipation at 85 °C ambient before TJ exceeds 150 °C. |
| PWM Dimming Ratio | 500:1 - achieves deep dimming down to 0.2% current while maintaining linearity via pulse-width compensation. |
| OVP Threshold | 19.5 V base (adjustable with ROVP) - protects external MOSFET, diode, and output capacitors from overvoltage stress. |
| LED Sink Regulation Voltage | 1.4 V at 80 mA - low dropout headroom minimizes power loss in high-Vf LED strings (e.g., 18× white LEDs). |
Pinout & Package
The A8512ELPTR-T is housed in a 24-pin TSSOP package (LP) with exposed thermal pad, optimized for single-sided PCB assembly and enhanced thermal dissipation (RθJA = 28 °C/W). Pin numbering follows standard TSSOP orientation (pin 1 marked).
| Pin | Circuit Role | Design Meaning |
|---|---|---|
| EN | Device Enable | Logic-high activates IC; low disables all functions including gate driver and LED sinks - used for system-level power sequencing. |
| PWM | Pulse-width modulation input | Directly controls LED current duty cycle; supports 100 Hz–5 kHz signals with <5 µs propagation delay to 90% ILED. |
| ISET | Current reference input | Sets full-scale LED current via external resistor (RISET); 1.235 V reference × 640 gain yields 64–130 mA/channel. |
| FSET | Frequency set input | Connects to ground via RFSET (51–174 kΩ) to program switching frequency from 300 kHz to 1 MHz. |
| SENSE1/SENSE2 | Boost current sense inputs | Differential pair measuring RSC voltage drop; enables cycle-by-cycle current limiting and soft-start control. |
| LED1–LED6 | LED current sink outputs | Each sinks up to 130 mA; unused pins must be grounded to prevent OVP fault during startup detection. |
| OVP | Overvoltage protection input | Connects to output capacitor via ROVP; trips shutdown when internal comparator detects >200 µA current. |
| FAULT | Open-drain fault indicator | Pulled low during OVP, short-detect, or thermal shutdown; requires external pull-up for system-level fault monitoring. |
Key Features
| Feature | Design Value |
|---|---|
| Parallel master/slave architecture | One master controls boost stage while up to five slaves act as current sinks - enables 36-LED-string scalability with single inductor. |
| No-audible-noise PWM dimming | Eliminates MLCC piezoelectric squeal by avoiding sub-20 kHz switching artifacts during dimming transitions. |
| Dual-level cycle-by-cycle current limit | Provides controlled soft-start ramp and robust overload protection without requiring external timing components. |
| Active current sharing | Maintains ±0.6% matching between enabled LED strings - critical for uniform luminance in multi-zone local dimming displays. |
| Exposed thermal pad (TSSOP-LP) | Enables 28 °C/W junction-to-ambient thermal resistance on 4-layer PCB - reduces thermal derating vs. SOICW (51 °C/W). |
Applications
| LCD Monitor Backlight | Television Local Dimming |
|---|---|
Use Scenario: Driving 6 parallel WLED strings (14–18 LEDs each) in 24–32 inch LCD monitors with dynamic brightness control. IC Role / Device Role / Timing Role: Primary LED current regulator and boost controller; manages PWM dimming synchronization and open-string recovery. Use Value: Enables consistent panel luminance with <±0.6% channel matching and automatic removal of failed strings without display blackout. |
Use Scenario: Multi-zone backlight control in 43–55 inch TVs using stacked A8512ELPTR-T devices (master + slaves) per zone. IC Role / Device Role / Timing Role: Zone-specific current sink controller; coordinates with master boost stage to regulate voltage only to active zones. Use Value: Reduces power consumption by 18–22% versus fixed-voltage boost by dynamically adjusting VOUT to minimum required for active LED strings. |
| Industrial Display Lighting | Medical Imaging Backlight |
Use Scenario: High-reliability backlight for ruggedized medical and industrial LCD panels operating in –40 to 85 °C ambient. IC Role / Device Role / Timing Role: Fault-tolerant LED driver with latched OVP, short-detect, and thermal shutdown - meets IEC 60601 safety margins. Use Value: Prevents catastrophic failure during LED string degradation; maintains partial illumination during single-string faults. |
Use Scenario: DICOM-compliant grayscale backlight for diagnostic monitors requiring stable luminance over 10,000-hour lifetime. IC Role / Device Role / Timing Role: Precision current source with <±0.6% matching and <0.2% PWM-induced current ripple at 200 Hz. Use Value: Eliminates luminance drift across gray levels - critical for accurate tissue contrast interpretation in radiology applications. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar LED backlight driver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM3409MH/NOPB | Single-channel buck-boost LED driver; no integrated current sinks; requires external FET and sense resistors per channel. | Designed for automotive headlamp and industrial lighting - lacks multi-string matching and master/slave sync capability. | Choose for cost-sensitive single-string designs where ±5% current matching is acceptable and board space allows discrete layout. |
| TPS61165DRVR | Single-output WLED driver with integrated boost and 40 V OVP; no multi-sink architecture or parallel operation support. | Targeted at portable displays (tablets, laptops); limited to 30 mA max per string and no thermal pad in 6-pin SOT-23. | Use only for low-power (<1 W) applications where A8512ELPTR-T's 36-string scalability and 130 mA/channel capability are unnecessary. |
Compared with A8512ELPTR-T, LM3409MH/NOPB offers greater flexibility in topology but requires significant external component count and lacks inherent current matching, while TPS61165DRVR provides simpler integration for small displays but cannot scale beyond one string or support the thermal and current demands of medium-size LCD backlights.
Availability
A8512ELPTR-T is available at Aetrix Electronics and suitable for LCD monitor backlighting, television local dimming systems, and industrial display lighting requiring stable component supply despite end-of-life status.
Supply support for A8512ELPTR-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 semiconductor company specializing in high-performance power ICs and magnetic sensors for automotive, industrial, and consumer applications.
The A8512 product line was designed specifically for medium-size LCD display backlighting, emphasizing multi-string current matching, scalable parallel architecture, and robust fault protection in thermally constrained environments.
FAQ
Is A8512ELPTR-T still in production?
No, A8512ELPTR-T is a discontinued product. Allegro MicroSystems ceased production as of December 1, 2015. It should not be selected for new design applications, and samples are no longer available. Aetrix Electronics maintains limited legacy stock for replacement and repair use only - verify current inventory before ordering A8512ELPTR-T.
What is the maximum LED current per channel for A8512ELPTR-T?
The A8512ELPTR-T supports up to 130 mA per LED channel, set by the ISET resistor value (RISET = 1.235 V / ISET). At 12.4 kΩ, it delivers 100 mA per string; lower RISET values increase current, but thermal limits constrain sustained operation above ~110 mA/channel on standard 4-layer PCBs.
How does A8512ELPTR-T handle an open LED string during operation?
When an open LED string occurs, A8512ELPTR-T detects the resulting voltage rise on the corresponding LEDx pin and triggers overvoltage protection. The faulty string is removed from regulation, while remaining strings continue normal operation at full current - preventing total backlight failure. Reconnecting the string restores regulation automatically.
Can A8512ELPTR-T be used without an external MOSFET?
No, A8512ELPTR-T requires an external N-channel MOSFET for its boost converter stage. It integrates only the gate driver (7 V regulated), current sensing, and feedback control. The MOSFET must be selected for voltage/current ratings matching the LED string requirements - e.g., IRFR120N or FQB17N08L as referenced in the A8512 datasheet.
What is the purpose of the exposed thermal pad on the A8512ELPTR-T TSSOP package?
The exposed thermal pad on the A8512ELPTR-T package must be soldered to a PCB ground plane to achieve its specified RθJA of 28 °C/W. Without proper thermal pad connection, junction temperature rises significantly - risking thermal shutdown at >1.0 W dissipation. This pad is electrically connected to PGND and LGND internally.
A8512ELPTR-T Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Allegro MicroSystems
- Series:
- -
- Package/Case:
- 24-TSSOP (0.173", 4.40mm Width) Exposed Pad
- 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):
- 8V
- Voltage - Supply (Max):
- 24V
- Voltage - Output:
- -
- Current - Output / Channel:
- -
- Frequency:
- 1MHz
- Dimming:
- PWM
- Applications:
- Backlight
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 24-TSSOP-EP
A8512ELPTR-T FAQ
1.How can I place an order for A8512ELPTR-T through Aetrix?
Please submit a Request for Quotation (RFQ) for A8512ELPTR-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 A8512ELPTR-T reliable?
The price and inventory of A8512ELPTR-T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for A8512ELPTR-T is usually 5 days.
3.What payment methods are accepted for A8512ELPTR-T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for A8512ELPTR-T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for A8512ELPTR-T?
A8512ELPTR-T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your A8512ELPTR-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 A8512ELPTR-T?
For technical support, including A8512ELPTR-T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your A8512ELPTR-T requirements.
6.How does Aetrix verify that A8512ELPTR-T is sourced from the original manufacturer or authorized distributors?
All A8512ELPTR-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 A8512ELPTR-T meets industry standards.
7.What is the process for return or replacement of A8512ELPTR-T?
All A8512ELPTR-T units undergo pre-shipment inspection (PSI). If there is an issue with A8512ELPTR-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 A8512ELPTR-T part is unused and in its original packaging.
Return procedure for A8512ELPTR-T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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