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Allegro MicroSystems A8501KLPTR-T
- Part No.:
- A8501KLPTR-T
- Manufacturer:
- Allegro MicroSystems
- Category:
- LED Drivers
- Package:
- 28-TSSOP (0.173", 4.40mm Width) Exposed Pad
- Datasheet:
-
A8501KLPTR-T.pdf
- Description:
- IC LED DRVR RGLTR PWM 28TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:2,973
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Product details
Overview
A8501KLPTR-T from Allegro MicroSystems is a discontinued 4-channel WLED/RGB backlight driver IC with integrated 40 V/3.6 A boost switch, 100 mA per channel current sinks, 2 MHz switching frequency, and output disconnect protection-designed for automotive LCD cluster and infotainment display backlighting.
For engineers reviewing the A8501KLPTR-T datasheet, A8501KLPTR-T pinout, A8501KLPTR-T application, or A8501KLPTR-T equivalent, this page delivers verified technical context, real-world dimming performance (4000:1 range), thermal derating capability via VTI, and validated alternative selection guidance for legacy design support and transition planning.
Technical Context
The A8501KLPTR-T implements a constant-frequency, current-mode boost converter with externally adjustable switching frequency (600 kHz–2.2 MHz via RFSET), integrated 40 V DMOS switch, and OVP-load-dump protection. It supports single-supply operation from 6.8 V to 21 V VIN while tolerating transient input up to 40 V.
Four matched LED current sinks deliver ±0.7% accuracy and 0.8% matching across –40°C to +125°C, with active current sharing, open/short LED detection, and true output disconnect via dedicated CAP/OUT pins. Thermal derating is enabled via external NTC on VTI/VTO, and PWM dimming achieves 1000:1 control with 4:1 analog extension via DIM pin.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Operating Temperature | –40°C to +125°C (Range K grade, qualified for under-hood automotive use) |
| LED Current per Channel | 100 mA (400 mA total sink capability when channels paralleled) |
| Boost Switch Rating | 40 V / 3.6 A (supports up to 9× 3.5 V LEDs per string at 100 mA) |
| Switching Frequency | 2 MHz typical (set by RFSET; avoids AM band interference) |
| Dimming Range | 4000:1 (1000:1 PWM + 4:1 analog via DIM pin) |
| Shutdown Current | 3.5 µA max (minimizes battery drain in always-on automotive systems) |
| OVP Threshold | 19.5 V default, adjustable up to 38 V (protects against load-dump transients) |
| Current Matching | 0.8% max mismatch between LED channels (ensures uniform display brightness) |
Pinout & Package
The A8501KLPTR-T is supplied in a 28-pin TSSOP package with exposed thermal pad (suffix LP), lead-free with 100% matte-tin plating (suffix T), optimized for thermal dissipation in high-brightness automotive displays.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| LED1–LED4 | Current sink outputs | Each sinks up to 100 mA; voltage compliance up to 21 V enables PWM dimming |
| VIN | Main power input | Accepts 6.8–21 V DC; withstands 40 V transients; powers internal bias supply |
| SW (pins 4–6) | Boost switch drain | Three tied pins handle 3.6 A peak; requires low-inductance PCB layout |
| OUT / CAP | Output disconnect interface | True hardware disconnect: OUT connects LED common; CAP enables latch-off during faults |
| ISET | Current reference input | RISET resistor sets 100% LED current (e.g., 12.4 kΩ → 100 mA) |
| DIM | Analog dimming control | Logic-level input: VIH = 240× gain, VIL = 960× gain for 4:1 current scaling |
| EN | Enable & PWM input | Direct PWM dimming control; low pulse >131k cycles triggers shutdown |
| VTI / VTO | Thermal derating interface | VTI accepts external NTC voltage; VTO provides 2.46 V reference for analog control |
| PGND / LGND / AGND / DGND / PAD | Ground terminals | Star-ground connection required; exposed PAD must be soldered to copper for thermal management |
Key Features
| Feature | Design Value |
|---|---|
| Integrated output disconnect switch | RODS(on) ≤ 4 Ω at 125°C enables safe fault isolation without external MOSFETs |
| Active current sharing | 0.8% matching and 0.7% accuracy ensure consistent luminance across multi-string displays |
| Thermal derating via VTI | External NTC on VTI reduces LED current linearly with panel temperature-prevents thermal runaway |
| Robust fault protection suite | Includes open/short LED detect, OVP (19.5–38 V), UVLO/OVLO, OTP (172°C trip), and SW overcurrent limit |
| AM-band-avoiding 2 MHz operation | Reduces EMI filtering requirements in sensitive infotainment head units |
| Low 3.5 µA shutdown current | Meets automotive "always-on" battery drain limits (<10 µA) across full temp range |
Applications
| Automotive Cluster Backlighting | Infotainment Display Backlight |
|---|---|
Use Scenario: High-reliability backlight for digital instrument clusters operating in under-hood environments (–40°C to +125°C). IC Role / Device Role / Timing Role: WLED driver with integrated boost, current regulation, and thermal derating-manages four independent LED strings for gauge illumination. Use Value: 0.8% current matching ensures uniform brightness across speedometer/tachometer segments; output disconnect prevents fault propagation during LED failure. |
Use Scenario: Brightness-controlled backlight for center-stack touchscreens in vehicles with varying ambient light conditions. IC Role / Device Role / Timing Role: RGB-capable driver delivering 4000:1 dimming via combined PWM (EN) and analog (DIM) control for seamless day/night transitions. Use Value: 2 MHz switching eliminates audible noise and avoids AM radio interference; 40 V OVP protects against load-dump transients in 12 V systems. |
| Backup Camera Display | Industrial LCD Panel |
Use Scenario: Compact, ruggedized display for rear-view camera systems requiring instant-on operation and wide temperature tolerance. IC Role / Device Role / Timing Role: Multi-string WLED driver enabling fast soft-start (≤2 ms turn-on via EN) and short-circuit protected output disconnect. Use Value: 3.5 µA shutdown current preserves vehicle battery during extended parking; open LED detection maintains partial functionality if one string fails. |
Use Scenario: Backlight for industrial HMI panels deployed in factory automation equipment with high ambient temperatures. IC Role / Device Role / Timing Role: Thermally managed LED driver using VTI/VTO interface with external NTC to reduce current as panel heats up. Use Value: Thermal derating extends LED lifetime and prevents color shift; 150°C max junction temperature rating supports convection-cooled enclosures. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar WLED/RGB backlight driver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| ALT80600 | Successor device with higher integration: integrated Schottky, improved efficiency, and extended OVP range (up to 42 V) | Designed for new designs; supports wider VIN (4.5–36 V) and higher LED string count (6 strings) | Recommended for all new designs; requires PCB layout revision due to different pinout and package (QFN) |
| LM3409QMY/NOPB | Standalone boost controller (no integrated LED sinks); requires external FET and current sense; no output disconnect or thermal derating interface | Used in cost-sensitive, non-automotive displays where discrete control is preferred | Only suitable for redesigns accepting added BOM count and layout complexity; lacks A8501KLPTR-T's integrated safety features |
Compared with A8501KLPTR-T, ALT80600 offers drop-in functional replacement with enhanced specs and automotive qualification, while LM3409QMY requires full system re-engineering but provides greater flexibility in topology and thermal management.
Availability
A8501KLPTR-T is available at Aetrix Electronics and suitable for automotive cluster backlighting, infotainment display systems, and industrial LCD panels requiring stable component supply despite end-of-life status.
Supply support for A8501KLPTR-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 automotive-grade motion control, current sensing, and LED driver solutions.
The A8501 product line was engineered specifically for automotive display backlighting-delivering robust, thermally aware, and EMI-optimized multi-channel LED driving in harsh under-hood and cabin environments.
FAQ
Is A8501KLPTR-T still in production?
No, A8501KLPTR-T is a discontinued product. Allegro MicroSystems ceased production as of July 1, 2024. Samples are no longer available, and the device should not be selected for new designs. Aetrix Electronics maintains limited legacy stock for existing production continuity and last-time buys.
What is the key difference between A8501KLPTR-T and A8501ELPTR-T?
The A8501KLPTR-T is rated for –40°C to +125°C (Range K), qualifying it for under-hood automotive applications, whereas A8501ELPTR-T is rated for –40°C to +85°C (Range E). Both share identical electrical specs, pinout, and package (28-pin TSSOP-LP), but only A8501KLPTR-T meets extended temperature requirements for engine compartment proximity.
Does A8501KLPTR-T support RGB driving, or only WLED?
A8501KLPTR-T supports both WLED and RGB configurations. Its four independent 100 mA current sinks can drive monochrome white LEDs or separate red/green/blue strings-enabling color-tunable backlighting. The datasheet explicitly lists "WLED/RGB Driver" in the title and confirms per-channel current control essential for RGB balance.
How does the output disconnect feature work on A8501KLPTR-T?
A8501KLPTR-T implements true hardware output disconnect using dedicated CAP and OUT pins. When a fault (e.g., shorted LED) is detected, the internal switch opens between CAP and OUT, physically isolating the LED strings from the boost output. This prevents damage and allows other channels to remain operational-unlike software-based disable methods that leave the output path energized.
Can A8501KLPTR-T be used with fewer than four LED strings?
Yes. A8501KLPTR-T supports selective channel enablement via SEL1/SEL2 logic pins: Low/Low enables only LED1; High/High enables all four. Unused LEDx pins may be left open or grounded-but if left floating while unselected, they must not exceed VLEDSC (19 V) to avoid false fault triggering. The datasheet confirms this configuration in Table 1 and Functional Description.
A8501KLPTR-T Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Allegro MicroSystems
- Series:
- -
- Package/Case:
- 28-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:
- 4
- Voltage - Supply (Min):
- 8V
- Voltage - Supply (Max):
- 21V
- Voltage - Output:
- -
- Current - Output / Channel:
- 100mA
- Frequency:
- 2MHz
- Dimming:
- PWM
- Applications:
- Backlight
- Operating Temperature:
- -40°C ~ 125°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 28-TSSOP-EP
A8501KLPTR-T FAQ
1.How can I place an order for A8501KLPTR-T through Aetrix?
Please submit a Request for Quotation (RFQ) for A8501KLPTR-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 A8501KLPTR-T reliable?
The price and inventory of A8501KLPTR-T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for A8501KLPTR-T is usually 5 days.
3.What payment methods are accepted for A8501KLPTR-T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for A8501KLPTR-T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for A8501KLPTR-T?
A8501KLPTR-T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your A8501KLPTR-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 A8501KLPTR-T?
For technical support, including A8501KLPTR-T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your A8501KLPTR-T requirements.
6.How does Aetrix verify that A8501KLPTR-T is sourced from the original manufacturer or authorized distributors?
All A8501KLPTR-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 A8501KLPTR-T meets industry standards.
7.What is the process for return or replacement of A8501KLPTR-T?
All A8501KLPTR-T units undergo pre-shipment inspection (PSI). If there is an issue with A8501KLPTR-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 A8501KLPTR-T part is unused and in its original packaging.
Return procedure for A8501KLPTR-T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
A8501KLPTR-T Tags
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BCR402RE6327HTSA1
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BCR430UXTSA2
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BCR420UE6433HTMA1
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BCR421UE6327HTSA1
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LYT1604D-TL
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HV9910CLG-G
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CL2N8-G
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BCR420UFD-7
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BCR421UFD-7
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