My Inquiry
My Account
Allegro MicroSystems A8522KLPTR-T
- Part No.:
- A8522KLPTR-T
- Manufacturer:
- Allegro MicroSystems
- Category:
- LED Drivers
- Package:
- 28-TSSOP (0.173", 4.40mm Width) Exposed Pad
- Datasheet:
-
A8522KLPTR-T.pdf
- Description:
- IC LED DRV RGLTR I2C 28TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:2,324
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
A8522KLPTR-T from Allegro MicroSystems is a fault-tolerant, I²C-programmable 8-channel LED driver IC for automotive LCD backlighting. It integrates a current-mode boost converter with internal DMOS switch, delivers up to 60 mA per channel, operates from 4.5 V to 36 V input, and withstands 40 V load-dump transients-enabling direct integration into infotainment and cluster displays.
For engineers reviewing the A8522KLPTR-T datasheet, A8522KLPTR-T pinout, A8522KLPTR-T application, or A8522KLPTR-T equivalent, this page provides verified technical context, real-world dimming performance (10,000:1 PWM), thermal derating behavior, and validated alternative options for automotive LED backlight systems requiring AEC-Q100 compliance and independent per-channel control.
Technical Context
The A8522KLPTR-T implements a fixed-frequency, current-mode boost regulator with programmable switching frequency (400 kHz–2.3 MHz) and dithering for EMI reduction. Its control loop includes soft-start, output voltage hysteresis, and polyphase PWM staggering across eight LED sinks to minimize input ripple and visible flicker.
It features dual-cycle-by-cycle switch current limiting (4.2 A typical), integrated OVP/UVP via OVP pin (programmable 7.5–40 V), thermal warning at 150°C and shutdown at 170°C, and comprehensive fault detection-including open/shorted LED pins, boost diode faults, and input overcurrent via INS/VIN differential sensing.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 4.5 V to 36 V - supports full automotive battery range including cold-crank (3.9 V dropout) and 40 V load-dump survival. |
| LED Current per Channel | Up to 60 mA (typical) - digitally programmable in 64 steps (1 mA resolution), with ±0.7% accuracy and ±0.8% channel-to-channel matching. |
| PWM Dimming Range | 10,000:1 at 100 Hz - enables ultra-fine local dimming control without visible flicker using polyphase staggered timing. |
| Boost Switch RDS(on) | 220 mΩ (typical) - internal NMOS switch reduces external component count and improves efficiency at high output power. |
| Thermal Protection | Warning at 150°C, shutdown at 170°C - automatic LED current derating above warning threshold ensures safe operation under sustained high ambient. |
| I²C Interface | Standard-mode (400 kHz max) - supports bidirectional fault reporting, register-based configuration of current, PWM, and protection thresholds per channel. |
| AEC-Q100 Grade | Grade 1 (–40°C to +125°C) - qualified for under-hood and display module applications in passenger vehicles. |
Pinout & Package
Package: 28-pin TSSOP with exposed thermal pad (suffix LP); RoHS-compliant, 100% matte tin plating; θJA = 28°C/W on 4-layer JEDEC board.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| GATE | External PMOS gate drive | Controls optional input-disconnect switch during overcurrent faults; sinks 115 µA, sources –6 mA when tripped. |
| INS | Input current sense input | Differential pair with VIN detects >105 mV drop (≈5.8 A at 18 mΩ RSENSE) to trigger input overcurrent protection. |
| LED1–LED8 | Current sink outputs | Eight independent, thermally compensated sinks; each configurable up to 60 mA with 0.85 V regulation voltage. |
| COMP | Error amplifier compensation node | Connects type-2 feedback network (R/C) to stabilize boost loop; ±200 µA sourcing/sinking capability. |
| FSET/SYNC | Frequency set/synchronization input | Resistor-to-GND sets fSW (400 kHz–2.3 MHz); accepts external clock for AM-band avoidance or EMI reduction. |
| FLAG | Active-low fault interrupt | Open-drain status indicator; asserts low on startup, fault, or thermal warning; requires 10–100 kΩ pull-up. |
| SDA / SCL | I²C bidirectional data/clock | Supports standard-mode communication (≤400 kHz); logic levels: VIL ≤ 0.8 V, VIH ≥ 2.3 V. |
| PAD | Exposed thermal pad | Must connect to PCB ground plane via ≥8 vias; primary thermal path for junction-to-board heat transfer. |
Key Features
| Feature | Design Value |
|---|---|
| Programmable polyphase PWM | Staggers LED channel on-times to reduce peak input current by >40% and eliminate visible flicker in high-resolution displays. |
| Integrated boost with OVP | Internal 220 mΩ NMOS switch + programmable output overvoltage protection (7.5–40 V) eliminates need for external OVP circuitry. |
| Automotive-grade fault coverage | Detects and reports open/shorted LED pins, missing boost diode, shorted inductor, IC overtemperature, and output-to-GND shorts. |
| Thermal derating with warning | Reduces LED current linearly above 150°C case temperature-preserves display brightness while preventing thermal runaway. |
| Load-dump tolerant design | Withstands 40 V transients on VIN and LEDx pins per AEC-Q100 stress testing-no external TVS required for ISO 7637-2 Pulse 5a. |
Applications
| Infotainment Display Backlight | Instrument Cluster Lighting |
|---|---|
|
Use Scenario: High-brightness, dynamically dimmed LCD backlight in center-stack infotainment units with variable ambient light conditions. IC Role / Device Role / Timing Role: Primary LED driver managing eight parallel strings (e.g., 7-series LEDs × 8 channels), delivering precise current and synchronized PWM dimming. Use Value: Enables 10,000:1 dimming ratio and polyphase timing to eliminate AM-band interference and ensure flicker-free video playback. |
Use Scenario: Compact, thermally constrained instrument cluster with segmented backlight zones requiring independent brightness control. IC Role / Device Role / Timing Role: Single-chip solution driving multiple LED zones (e.g., speedometer, tachometer, warning icons) with individual I²C-addressable current and PWM settings. Use Value: Reduces BOM count vs. discrete drivers; thermal derating maintains consistent luminance across –40°C to +125°C operating range. |
| Head-Up Display (HUD) Illumination | Daytime Running Light (DRL) Control |
|
Use Scenario: HUD projection system requiring stable, low-noise LED current to avoid image distortion and maintain contrast in bright sunlight. IC Role / Device Role / Timing Role: Precision current sink providing <±0.7% accuracy and <±0.8% matching across channels for uniform optical output. Use Value: Minimizes luminance variation between projector segments; COMP-loop stability prevents brightness drift during rapid temperature changes. |
Use Scenario: Automotive DRL module needing robust operation during engine cranking (3.9 V minimum) and load-dump events (40 V). IC Role / Device Role / Timing Role: Fault-tolerant LED driver with UVLO hysteresis (400 mV), load-dump immunity, and integrated diagnostics for ASIL-B–aligned systems. Use Value: Eliminates need for external protection components; FLAG pin enables real-time fault logging for functional safety compliance. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar multi-channel LED driver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX20052ATP/V+T | 6-channel, 100 mA/channel; no integrated boost; requires external inductor and diode; 3.5–36 V input. | Lacks integrated boost and polyphase PWM; suitable only where board space allows external power stage and lower channel count suffices. | Choose when higher per-channel current (>60 mA) is needed and external boost design is acceptable. |
| TPS92692QPWPRQ1 | 2-channel, 150 mA/channel; integrated boost; I²C + analog dimming; 4.5–40 V input; no polyphase or load-dump rating. | Lower channel count; lacks AEC-Q100 Grade 1 thermal range and 40 V transient tolerance; no thermal derating feature. | Choose for simpler 2-string designs where AEC-Q100 Grade 0 (–40°C to +105°C) suffices and polyphase is unnecessary. |
Compared with MAX20052ATP/V+T and TPS92692QPWPRQ1, the A8522KLPTR-T uniquely combines 8-channel integration, internal boost, AEC-Q100 Grade 1 qualification, 40 V load-dump tolerance, and polyphase PWM-making it the only single-package solution for high-channel-count automotive displays requiring flicker-free dimming and full transient robustness.
Availability
A8522KLPTR-T is available at Aetrix Electronics and suitable for automotive infotainment systems, digital instrument clusters, and head-up displays requiring stable component supply, AEC-Q100 compliance, and long-term production continuity.
Supply support for A8522KLPTR-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 power ICs and magnetic sensors, specializing in automotive and industrial motion control solutions.
The A8522 product line was developed specifically for fault-tolerant, multi-zone LED backlighting in automotive displays-emphasizing AEC-Q100 reliability, wide-input resilience, and software-configurable dimming precision.
FAQ
What is the maximum LED string voltage supported by the A8522KLPTR-T?
The A8522KLPTR-T does not specify a fixed maximum LED string voltage; instead, its output overvoltage protection (OVP) is programmable from 7.5 V to 40 V via the OVP register. The secondary OVP threshold at the SW pin is 44 V, ensuring safe operation even during transient overvoltage events. Actual string voltage depends on LED count, forward voltage, and boost inductor selection-but must remain below the configured OVP limit to avoid shutdown.
Does the A8522KLPTR-T support synchronization to an external clock source?
Yes, the A8522KLPTR-T supports external synchronization via the FSET/SYNC pin. When driven with a clean square wave (≥150 ns min on/off time, logic-high ≥2 V), the internal boost switching frequency locks to the external signal across 400 kHz–2.3 MHz. This enables EMI reduction by shifting switching noise away from sensitive bands (e.g., AM radio) and facilitates multi-IC phase alignment in large display systems.
How does thermal derating work on the A8522KLPTR-T?
The A8522KLPTR-T monitors die temperature and triggers thermal warning at 150°C, initiating linear LED current reduction. At 170°C, it enters thermal shutdown. Derating begins gradually above the warning threshold-ensuring display brightness remains usable while preventing damage. The slope and offset are factory-trimmed; no external components or register writes are needed to activate this behavior.
Can unused LEDx pins be left floating on the A8522KLPTR-T?
No. Per the datasheet (page A-8), all unused LEDx pins must be connected to GND through a 4.7 kΩ resistor. Floating LEDx pins may cause unpredictable current leakage, false fault detection, or instability in the current-sink reference. This requirement applies to any channel not actively driving an LED string-even if disabled via I²C register.
What protection features are implemented in hardware versus firmware on the A8522KLPTR-T?
Hardware protections include cycle-by-cycle switch current limiting (4.2 A typical), input overcurrent detection (via INS/VIN differential), output overvoltage/undervoltage (OVP pin), thermal shutdown (170°C), and LED open/short detection-all active without I²C communication. Firmware-configurable protections (e.g., programmable OVP threshold, short-detect voltage, thermal warning level) rely on register writes but execute in dedicated analog comparators-not software polling.
A8522KLPTR-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:
- Active
- Type:
- DC DC Regulator
- Topology:
- Step-Up (Boost)
- Internal Switch(s):
- Yes
- Number of Outputs:
- 8
- Voltage - Supply (Min):
- 4.5V
- Voltage - Supply (Max):
- 36V
- Voltage - Output:
- 40V
- Current - Output / Channel:
- 60mA
- Frequency:
- 400kHz ~ 2.3MHz
- Dimming:
- I2C, PWM
- Applications:
- Backlight, Lighting
- Operating Temperature:
- -40°C ~ 125°C (TA)
- Grade:
- Automotive
- Qualification:
- AEC-Q100
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 28-TSSOP-EP
A8522KLPTR-T FAQ
1.How can I place an order for A8522KLPTR-T through Aetrix?
Please submit a Request for Quotation (RFQ) for A8522KLPTR-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 A8522KLPTR-T reliable?
The price and inventory of A8522KLPTR-T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for A8522KLPTR-T is usually 5 days.
3.What payment methods are accepted for A8522KLPTR-T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for A8522KLPTR-T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for A8522KLPTR-T?
A8522KLPTR-T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your A8522KLPTR-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 A8522KLPTR-T?
For technical support, including A8522KLPTR-T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your A8522KLPTR-T requirements.
6.How does Aetrix verify that A8522KLPTR-T is sourced from the original manufacturer or authorized distributors?
All A8522KLPTR-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 A8522KLPTR-T meets industry standards.
7.What is the process for return or replacement of A8522KLPTR-T?
All A8522KLPTR-T units undergo pre-shipment inspection (PSI). If there is an issue with A8522KLPTR-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 A8522KLPTR-T part is unused and in its original packaging.
Return procedure for A8522KLPTR-T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
A8522KLPTR-T Tags
-
BCR402RE6327HTSA1
Infineon Technologies
-
BCR430UXTSA2
Infineon Technologies
-
BCR420UE6433HTMA1
Infineon Technologies
-
BCR420UE6327HTSA1
Infineon Technologies
-
BCR421UE6327HTSA1
Infineon Technologies
-
LYT1604D-TL
Power Integrations
-
HV9910CLG-G
Microchip Technology
-
CL2N8-G
Microchip Technology
-
BCR420UW6-7
Diodes Incorporated
-
BCR421UW6-7
Diodes Incorporated
-
BCR420UFD-7
Diodes Incorporated
-
BCR421UFD-7
Diodes Incorporated
Tech Hub
A practical engineering and sourcing framework covering lifecycle verification, lifetime-buy calculations, replacement qualification, supplier checks and counterfeit-risk controls.
TTL and CMOS logic families differ in thresholds, loading, output drive, power and timing. This engineering guide compares 74HC and 74HCT, calculates noise margins and checks 3.3 V/5 V compatibility.
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…
