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Allegro MicroSystems A8518KLPTR-T
- Part No.:
- A8518KLPTR-T
- Manufacturer:
- Allegro MicroSystems
- Category:
- LED Drivers
- Package:
- 16-TSSOP (0.173", 4.40mm Width) Exposed Pad
- Datasheet:
-
A8518KLPTR-T.pdf
- Description:
- IC LED DRVR RGLTR PWM 16ETSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:4,867
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Product details
Overview
A8518KLPTR-T from Allegro MicroSystems is a discontinued automotive-grade LED driver IC designed for dual-string LCD backlighting in infotainment and instrument cluster systems. It integrates a 2.15 MHz current-mode boost converter with internal 42 V MOSFET, two matched 200 mA LED current sinks, and fault-tolerant protection including OVP, OTP, LED short/open detection, and input overcurrent latching. It operates from 4.5–40 V input and supports 10,000:1 PWM dimming at 100 Hz.
For engineers reviewing the A8518KLPTR-T datasheet, A8518KLPTR-T pinout, A8518KLPTR-T application, or A8518KLPTR-T equivalent, this page delivers verified technical context on its fixed-frequency boost architecture, dithering-enabled EMI reduction, thermal shutdown behavior at 170°C, gate driver capability for external P-channel disconnect switches, and precise LED current matching (±0.8%) - all critical for legacy automotive backlight redesigns and lifecycle management.
Technical Context
The A8518KLPTR-T implements a current-mode boost controller with a fixed 2.15 MHz switching frequency and integrated dithering to suppress EMI peaks. Its dual independent LED current sinks are trimmed for 0.7% absolute accuracy and 0.8% inter-string matching, referenced to a 1.017 V ISET pin voltage.
Protection logic includes cycle-by-cycle boost switch current limiting (3.65 A typ), VOUT-to-GND short detection via GATE-controlled P-MOSFET, and thermal shutdown at 170°C with 20°C hysteresis. The device uses a dedicated VSENSE pin for input current sensing with 110 mV trip threshold and supports analog trimming via APWM pin at 40–1000 kHz.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 4.5–40 V - withstands automotive load dump transients up to 40 V and supports idle-stop operation down to 3.9 V after startup. |
| Boost Switching Frequency | 2.15 MHz (±10%) with dithering - operates above AM band and reduces conducted EMI without external filters. |
| LED Current per String | 200 mA - set by RISET resistor (e.g., 7.15 kΩ) with 0.7% accuracy and 0.8% matching between LED1/LED2 sinks. |
| PWM Dimming Ratio | 10,000:1 at 100 Hz - enables ultra-low-duty-cycle backlight control (1 µs on-time) with sub-500 ns LED turn-on delay. |
| Thermal Shutdown Threshold | 170°C (rising) with 20°C hysteresis - protects against sustained overtemperature in enclosed automotive enclosures. |
| OVP Protection Level | Adjustable via ROVP resistor; typical 8.3 V threshold at OVP pin with ±5% accuracy - prevents LED string overvoltage damage. |
| Package Thermal Resistance | 34°C/W (JEDEC 4-layer PCB) - requires exposed thermal pad soldered with ≥8 vias to AGND for reliable 125°C ambient operation. |
Pinout & Package
Package: 16-pin TSSOP with exposed thermal pad (suffix LP); RoHS-compliant, 100% matte tin leadframe plating.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 COMP | Error amplifier output & compensation node | Connect RZ-CZ-CP network to ground for loop stability; sets boost regulation bandwidth and transient response. |
| 2 PGND | Power ground for internal N-MOSFET | Must be low-inductance connection to PCB ground plane; separates power return from signal ground (AGND). |
| 3 OVP | Overvoltage sense input | Connect ROVP from VOUT to set OVP threshold (e.g., 160 kΩ → ~8.3 V); trips if VOUT exceeds programmed level. |
| 4 VOUT | Boost output voltage node | Direct connection to boost capacitor; monitored for OVP, UVP, and VOUT-to-GND short detection during startup. |
| 5 SW | Internal N-MOSFET drain | Switches at 2.15 MHz; rated for 48 V transient; connects to boost inductor and diode anode. |
| 6 GATE | External P-MOSFET gate driver | Drives high-side disconnect switch during faults; sinks –113 µA and sources 6 mA during OCP events. |
| 7 VSENSE | Input current sense reference | Senses VIN–VSENSE differential; 110 mV trip point enables input overcurrent protection and latch-off behavior. |
| 8 VIN | Main power input | Supplies IC bias and boost switch; UVLO activates at 4.35 V rising, deactivates at 3.9 V falling. |
| 9 FAULT | Open-drain fault indicator | Pulled low on OVP, OTP, LED short/open, or input OCP; requires 100 kΩ pull-up to logic voltage. |
| 10 VDD | Internal LDO output | Provides 5 V bias for internal circuitry; requires 1 µF ceramic decoupling capacitor to AGND. |
| 11 PWM | Enable & digital dimming input | High = enable + 100% LED current; low = shutdown; supports 100–400 Hz PWM dimming with <0.5 µs timing delays. |
| 12 APWM | Analog trim/dimming control | 40–1000 kHz digital input; duty cycle inversely controls ISET current to adjust max LED current without changing RISET. |
| 13 ISET | LED current reference input | 1.017 V reference; connect RISET to AGND to set LED current (e.g., 7.15 kΩ → 200 mA per string). |
| 14 AGND | LED current sink ground | Separate ground return for LED strings; must tie to system ground with low-impedance path. |
| 15 LED1 | First LED current sink output | Connect cathode of first LED string; unused pin must terminate to AGND via 1.54 kΩ resistor. |
| 16 LED2 | Second LED current sink output | Connect cathode of second LED string; same termination requirement as LED1 when unused. |
| PAD | Exposed thermal pad | Mandatory connection to AGND plane with ≥8 thermal vias; primary path for heat dissipation in high-power operation. |
Key Features
| Feature | Design Value |
|---|---|
| Dithered 2.15 MHz boost switching | Reduces EMI peak amplitude by spreading energy across 100–200 kHz bandwidth - eliminates need for large EMI filters in space-constrained clusters. |
| Matched dual 200 mA LED sinks | 0.8% inter-string current matching ensures uniform brightness across left/right display zones without software calibration. |
| VOUT-to-GND short protection | Uses GATE-driven external P-MOSFET to disconnect VIN within 3 µs of fault detection - prevents catastrophic failure during assembly or field shorts. |
| 10,000:1 PWM dimming at 100 Hz | Enables 1 µs minimum on-time with <500 ns LED turn-on delay - supports deep dimming for night-mode displays without visible flicker. |
| Automotive AEC-Q100 Grade 1 qualified | Rated for –40°C to +125°C ambient operation with full electrical specs guaranteed - validated for under-hood and dashboard environments. |
Applications
| Automotive Infotainment Backlighting | Automotive Instrument Cluster |
|---|---|
|
Use Scenario: Driving 11-white-LED strings per channel in center-stack touchscreen displays with dynamic brightness control. IC Role / Device Role / Timing Role: Dual-string LED driver with integrated boost converter and dithered 2.15 MHz switching for EMI compliance in crowded RF environments. Use Value: Eliminates need for external boost controller and discrete current sinks while maintaining 0.8% string matching for consistent color temperature. |
Use Scenario: Powering segmented LCD gauges and warning indicators requiring stable 200 mA per string across wide temperature and input voltage ranges. IC Role / Device Role / Timing Role: Fault-tolerant LED driver with OVP, OTP, and LED open/short detection to ensure fail-safe illumination in safety-critical instrumentation. Use Value: Built-in diagnostics reduce BOM count and enable early fault reporting via FAULT pin, supporting ASIL-B functional safety requirements. |
| Automotive Center Stack | Commercial Vehicle Display Modules |
|
Use Scenario: Backlighting multi-zone LCD panels in premium vehicle center consoles with independent dimming per zone using APWM trimming. IC Role / Device Role / Timing Role: Analog-trimmable LED driver enabling fine-grained current adjustment (via APWM pin) without hardware changes to RISET resistors. Use Value: Supports post-production brightness calibration and aging compensation through digital APWM signals, extending display lifetime. |
Use Scenario: Illuminating ruggedized displays in trucks and construction equipment exposed to 40 V load dump transients and extended temperature cycles. IC Role / Device Role / Timing Role: Wide-input (4.5–40 V), AEC-Q100 qualified LED driver with 34°C/W thermal resistance for reliable operation in uncooled enclosures. Use Value: Withstands automotive-grade surge conditions without external TVS, reducing system-level protection component count and cost. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar LED driver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AL8862T-7 | Fixed 2.2 MHz frequency, no dithering; 150 mA max per channel; no APWM pin; requires external boost MOSFET. | Lacks integrated switch and analog trim, limiting use to lower-current, non-automotive displays where EMI is less constrained. | Select AL8862T-7 only for cost-sensitive non-AEC-Q100 designs with ≤150 mA per string and no need for VOUT-to-GND short protection. |
| LM3409QMY/NOPB | Adjustable 200–2000 kHz frequency; 1.25 A switch current; no integrated LED sinks; requires external current sense and PWM interface. | Requires full external LED current regulation circuitry; suitable for high-current single-string or custom multi-string topologies. | Choose LM3409QMY/NOPB when designing flexible, scalable LED drivers beyond 200 mA per string or needing programmable frequency tuning. |
Compared with A8518KLPTR-T, AL8862T-7 offers lower integration and reduced EMI mitigation, while LM3409QMY/NOPB provides higher current capability but demands significantly more external components and layout effort - making A8518KLPTR-T optimal for compact, AEC-Q100-compliant dual-string automotive backlighting where dithering and fault tolerance are mandatory.
Availability
A8518KLPTR-T is available at Aetrix Electronics and suitable for automotive infotainment backlighting, instrument cluster illumination, and commercial vehicle display modules requiring stable component supply despite end-of-life status.
Supply support for A8518KLPTR-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 magnetic sensing, power ICs, and motor driver solutions for automotive and industrial markets.
The A8518 product line was engineered specifically for AEC-Q100-compliant automotive LCD backlighting, emphasizing fault tolerance, wide-input operation, and EMI-reduced switching to meet stringent OEM EMC requirements.
FAQ
Is the A8518KLPTR-T still in production?
No, the A8518KLPTR-T is a discontinued product. Allegro MicroSystems officially ended production as of September 11, 2024. 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 of existing systems.
What is the key functional difference between A8518KLPTR-T and A8518KLPTR-T-1?
The A8518KLPTR-T includes boost switching frequency dithering to reduce EMI, while the A8518KLPTR-T-1 omits this feature. All other electrical specifications, pinout, package, and protection functions are identical between the two variants.
Can the A8518KLPTR-T drive more than 200 mA per LED string?
No - the A8518KLPTR-T is specified for maximum 200 mA per string. However, its two current sinks can be paralleled externally to achieve up to 400 mA total output, provided thermal limits and PCB layout support the increased current density and power dissipation.
Does the A8518KLPTR-T support analog dimming alone, or only in combination with PWM?
The A8518KLPTR-T supports analog dimming exclusively via the APWM pin, which adjusts the ISET current digitally. It does not support continuous analog voltage-based dimming. For highest contrast ratios, Allegro recommends combining APWM trimming with PWM dimming to achieve 100,000:1.
What thermal derating applies to the A8518KLPTR-T at 125°C ambient?
At 125°C ambient, the A8518KLPTR-T's maximum allowable power dissipation is limited by its 34°C/W junction-to-ambient thermal resistance and 150°C max junction temperature. This results in ~7.4 W absolute maximum power, requiring careful layout with the exposed pad fully soldered and thermally vias to maintain safe operation.
A8518KLPTR-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):
- 4.5V
- Voltage - Supply (Max):
- 40V
- Voltage - Output:
- 40V
- Current - Output / Channel:
- 200mA
- Frequency:
- 2.15MHz
- Dimming:
- Analog, PWM
- Applications:
- Backlight
- Operating Temperature:
- -40°C ~ 125°C (TA)
- Grade:
- Automotive
- Qualification:
- AEC-Q100
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-eTSSOP-EP
A8518KLPTR-T FAQ
1.How can I place an order for A8518KLPTR-T through Aetrix?
Please submit a Request for Quotation (RFQ) for A8518KLPTR-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 A8518KLPTR-T reliable?
The price and inventory of A8518KLPTR-T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for A8518KLPTR-T is usually 5 days.
3.What payment methods are accepted for A8518KLPTR-T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for A8518KLPTR-T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for A8518KLPTR-T?
A8518KLPTR-T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your A8518KLPTR-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 A8518KLPTR-T?
For technical support, including A8518KLPTR-T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your A8518KLPTR-T requirements.
6.How does Aetrix verify that A8518KLPTR-T is sourced from the original manufacturer or authorized distributors?
All A8518KLPTR-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 A8518KLPTR-T meets industry standards.
7.What is the process for return or replacement of A8518KLPTR-T?
All A8518KLPTR-T units undergo pre-shipment inspection (PSI). If there is an issue with A8518KLPTR-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 A8518KLPTR-T part is unused and in its original packaging.
Return procedure for A8518KLPTR-T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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