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Allegro MicroSystems A8591KEJTR-J-1
- Part No.:
- A8591KEJTR-J-1
- Manufacturer:
- Allegro MicroSystems
- Package:
- 10-WFDFN Exposed Pad
- Datasheet:
-
A8591KEJTR-J-1.pdf
- Description:
- IC REG BUCK 3.3V 2A 10DFN
- Quantity:
- Payment:
- Shipping:
Inventory:2,976
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Product details
Overview
A8591KEJTR-J-1 from Allegro MicroSystems is a wide-input, 2 A automotive-grade buck regulator with fixed 3.3 V ±1% output, integrated 110 mΩ high-side MOSFET, pulse-frequency modulation (PFM) low-IQ mode (20 µA at 12 VIN/40 µA load), and AEC-Q100 qualification for car audio and infotainment power supplies.
For engineers reviewing the A8591KEJTR-J-1 datasheet, A8591KEJTR-J-1 pinout, A8591KEJTR-J-1 application, or A8591KEJTR-J-1 equivalent, this page delivers verified technical context, real-world design meaning of key specs, validated pin functions, automotive thermal and protection behavior, and two confirmed alternative parts for 3.3 V buck regulation in harsh-environment embedded systems.
Technical Context
The A8591KEJTR-J-1 implements current-mode control with external compensation (COMP pin), enabling stable operation across ceramic or electrolytic output capacitors and wide duty-cycle ranges. Its adjustable PWM frequency (300 kHz–2.4 MHz via RFSET resistor) supports EMI reduction through dithering (±7.5%) and external synchronization.
It features three operational modes: full PWM (up to 2 A), low-IQ PFM (20 µA typical quiescent current at no load), and sleep shutdown (<10 µA). Protection includes pulse-by-pulse current limit (3.5 A typ), hiccup-mode short-circuit response, BOOT open/short detection, VIN UVLO (3.4 V typ start), and thermal shutdown (170°C trip).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 3.3 V ±1% accuracy over –40°C to 150°C junction temperature - ensures stable MCU core/logic rail without external feedback resistors. |
| Max Output Current | 2 A continuous - supports high-power audio amplifiers and multi-core infotainment SoCs under thermally optimized PCB layout. |
| Input Voltage Range | 4 V to 35 V - accommodates automotive battery transients including 40 V load dump (with external TVS) and idle-stop 3.4 V brownout. |
| Quiescent Current (PFM) | 20 µA at 12 VIN, no load, 25°C - enables >1-year battery standby in always-on vehicle modules without compromising wake-up latency. |
| Switching Frequency | Adjustable 300 kHz–2.4 MHz - allows EMI tuning, inductor size optimization, and synchronization to system clock to avoid beat frequencies. |
| Package | 10-pin 3 × 3 mm wettable-flank DFN with exposed thermal pad - provides 45°C/W θJA on 4-layer JEDEC board and enables automated optical solder inspection (AOI). |
| Protection Features | Pulse-by-pulse OCP, hiccup-mode SCP, BOOT fault detection, VIN UVLO with 400 mV hysteresis, and thermal shutdown with 20°C hysteresis - eliminates need for external fault monitoring circuitry. |
Pinout & Package
Package: 10-pin, 3 × 3 mm wettable-flank DFN (EJ suffix) with exposed thermal pad - lead-free, matte tin plating, RoHS-compliant, designed for high-reliability automotive reflow and AOI.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 2 - VIN | Power input for control logic and high-side MOSFET drain | Must be decoupled with high-frequency ceramic capacitor near pins; supports 4–35 V input with surge tolerance up to 40 V (with external protection). |
| 3 - EN/SLEEP | Enable/shutdown control input | Logic-high (>2.1 V) enables regulation; logic-low (<1.2 V) forces ultralow-IQ sleep mode (<10 µA); 224 µs internal delay prevents false triggering from noise. |
| 4 - FSET/SYNCPWM | Frequency setting and external clock sync input | Resistor-to-GND sets switching frequency; external clock (0.375–2.4 MHz) forces PWM mode and disables dithering - critical for EMI-sensitive infotainment stacks. |
| 5 - VOUT | Regulated output and internal feedback node | Connects to on-chip 2× resistor divider (for 3.3 V output); Kelvin routing recommended to minimize sensing error and ensure ±1% regulation accuracy. |
| 6 - NPOR | Active-low power-on reset output | Open-drain signal with 7.5 ms delay after VOUT reaches regulation; asserts low if VOUT drops below 3.05 V (3.3 V version) - directly interfaces with MCU reset inputs. |
| 7 - COMP | Error amplifier output and loop compensation node | External RZ/CZ/CP network required for stability; transconductance = 181.8 µA/V (typ) - enables robust transient response across wide output capacitor ESR range. |
| 8 - GND | Analog and power ground reference | Shared return for control circuitry and high-current paths; must be connected to thermal pad vias to maintain <150°C junction temperature at 2 A load. |
| 9 - SW | Switch node (high-side MOSFET source) | Connects to external freewheeling diode and output inductor; fast slew rate (0.72 V/ns) demands short, wide traces to minimize EMI and ringing. |
| 10 - BOOT | High-side gate drive bootstrap supply | 47 nF ceramic capacitor between BOOT and SW required; internal BOOT regulator enables reliable high-side drive even at low VIN (down to 3.4 V). |
| Pad - Exposed Thermal Pad | Primary thermal dissipation path | Mandatory connection to PCB ground plane via ≥6 thermal vias; failure to route causes thermal shutdown at <1.5 A under worst-case ambient conditions. |
Key Features
| Feature | Design Value |
|---|---|
| Low-IQ PFM Mode | 20 µA typical IIN at 12 VIN/no load enables >1-year battery life in always-on telematics modules without sacrificing startup speed. |
| Pre-biased Startup | VOUT rises monotonically even when output capacitor is pre-charged - prevents system reset during hot-plug or power-rail sequencing in multi-rail infotainment designs. |
| EMI Reduction Suite | Frequency dithering (±7.5%), controlled SW node slew rate, and external sync capability meet CISPR-25 Class 5 requirements for automotive audio subsystems. |
| Automotive Qualification | AEC-Q100 Grade 1 (–40°C to +125°C ambient / –40°C to +150°C junction) and 40 V load-dump survivability - certified for instrument cluster, head unit, and ADAS display power rails. |
| Robust Fault Tolerance | Pin open/short detection, BOOT voltage fault monitoring, and hiccup-mode recovery allow safe operation in unattended vehicle environments without external supervision. |
Applications
| Instrument Clusters | Car Audio Amplifiers |
|---|---|
|
Use Scenario: Powering digital gauges, TFT LCD drivers, and microcontroller cores in modern digital dashboards with variable backlight loads and CAN/FlexRay communication. IC Role / Device Role / Timing Role: Primary 3.3 V buck regulator supplying logic rails for MCU, display controller, and sensor interface ICs. Use Value: ±1% output accuracy maintains ADC reference stability; low-IQ PFM extends battery runtime during key-off monitoring; AEC-Q100 compliance ensures functional safety alignment. |
Use Scenario: Generating clean 3.3 V supply for DSP, DAC, and Class-D amplifier control logic in premium OEM audio head units with Bluetooth/Audio-Over-IP streaming. IC Role / Device Role / Timing Role: Secondary regulated rail isolated from noisy 12 V battery input, synchronized to system clock to suppress audible switching artifacts. Use Value: External sync capability eliminates beat frequencies with audio sampling clocks; EMI dithering meets strict EMC limits for cabin audio fidelity. |
| Infotainment Head Units | HVAC Control Modules |
|
Use Scenario: Providing stable 3.3 V for application processors, Wi-Fi/BT SoCs, and touch controller in Android Automotive-based navigation systems with dual-display outputs. IC Role / Device Role / Timing Role: High-current, thermally robust DC-DC stage delivering 2 A peak to support burst-mode CPU loading during map rendering or voice recognition. Use Value: 2 A rating and 45°C/W thermal resistance sustain full load at 85°C ambient; pre-biased startup avoids reset during firmware OTA updates. |
Use Scenario: Powering microcontrollers, motor drivers, and ambient sensors in climate control panels exposed to under-hood temperature cycling and vibration. IC Role / Device Role / Timing Role: Main system regulator converting 12 V battery to 3.3 V logic rail, operating continuously across –40°C to +105°C ambient with no derating. Use Value: Wide VIN range (4–35 V) handles cold-crank dips and alternator surges; integrated protection eliminates need for discrete OVP/OTP circuits. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar 3.3 V buck regulation applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MPQ4420AGL-AEC1-Z | Fixed 3.3 V, 2 A, AEC-Q100, but uses voltage-mode control and lacks PFM low-IQ mode (IQ = 45 µA typical) | Higher light-load quiescent current reduces battery standby time in always-on modules | Choose when external compensation flexibility is not required and cost sensitivity outweighs ultra-low-IQ needs |
| TPS54202HDDCR | 3.3 V adjustable (requires feedback resistors), 2 A, AEC-Q100, integrated soft-start, but no NPOR output or BOOT fault detection | Lacks dedicated power-on reset signaling and advanced fault diagnostics needed for ASIL-B adjacent systems | Choose for simpler designs where reset coordination is handled externally and BOOT reliability is less critical |
Compared with MPQ4420AGL-AEC1-Z and TPS54202HDDCR, the A8591KEJTR-J-1 uniquely combines 20 µA PFM quiescent current, integrated NPOR with programmable thresholds, and BOOT fault monitoring - making it optimal for automotive modules requiring long battery life, deterministic reset behavior, and robust high-side gate drive integrity.
Availability
A8591KEJTR-J-1 is available at Aetrix Electronics and suitable for automotive instrument clusters, infotainment head units, and HVAC control modules requiring stable component supply, AEC-Q100 compliance, and long-term production continuity.
Supply support for A8591KEJTR-J-1 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 and power conversion solutions.
The A8591 family targets next-generation car audio and infotainment systems, delivering high-current, low-quiescent buck regulation with integrated protection and AEC-Q100 qualification for harsh automotive environments.
FAQ
What is the guaranteed output voltage accuracy of the A8591KEJTR-J-1 over temperature?
The A8591KEJTR-J-1 guarantees ±1% output voltage accuracy across its full operating junction temperature range of –40°C to +150°C. At 0°C to +85°C, the 3.3 V output is specified from 3.267 V to 3.333 V; at –40°C to +150°C, it tightens to 3.25 V to 3.35 V. This accuracy is achieved using an internal 2× resistor divider and 800 mV reference, eliminating external resistor tolerance errors - a key advantage over adjustable buck regulators in safety-critical automotive applications.
Does the A8591KEJTR-J-1 support pre-biased startup, and why does it matter?
Yes, the A8591KEJTR-J-1 supports pre-biased startup: when powered on with a pre-charged output capacitor, VOUT increases monotonically without droop or reversal. This prevents unintended MCU resets during hot-plug events, firmware updates, or multi-rail power sequencing in infotainment systems. Unlike many buck controllers that force discharge before ramp-up, the A8591KEJTR-J-1's internal architecture actively manages current flow to maintain monotonic rise - a verified feature critical for automotive software-defined vehicle architectures.
How does the A8591KEJTR-J-1 achieve ultra-low quiescent current in PFM mode?
The A8591KEJTR-J-1 achieves 20 µA typical quiescent current in PFM mode by dynamically reducing switching frequency under light load while maintaining regulation. At no load and 12 VIN, it draws just 7 µA (25°C) to 12 µA (65°C); at 40 µA load, it consumes 20–25 µA. This is enabled by a dedicated low-power oscillator and bias circuitry that remains active while disabling high-current drivers - allowing >1-year battery standby in telematics modules without compromising wake-up latency or output stability.
What protection features are integrated into the A8591KEJTR-J-1, and how do they improve system reliability?
The A8591KEJTR-J-1 integrates pulse-by-pulse current limit (3.5 A typ), hiccup-mode short-circuit protection, BOOT open/short detection, VIN undervoltage lockout (3.4 V start), and thermal shutdown (170°C trip with 20°C hysteresis). These eliminate the need for external fault monitoring ICs or discrete protection components. For example, BOOT fault detection prevents high-side MOSFET shoot-through during capacitor failure, while hiccup mode safely recovers from sustained shorts - significantly improving field reliability in unattended automotive modules.
Can the A8591KEJTR-J-1 be synchronized to an external clock, and what are the timing requirements?
Yes, the A8591KEJTR-J-1 can be synchronized to an external clock applied to the FSET/SYNCPWM pin. Valid synchronization requires input frequency between 0.375 MHz and 2.4 MHz, duty cycle ≤80%, pulse width ≥200 ns, rise/fall times ≤15 ns, and threshold crossing within 16 µs. When synchronized, frequency dithering is disabled and the device operates strictly in PWM mode - essential for EMI-sensitive infotainment systems where switching noise must align precisely with system timing domains.
A8591KEJTR-J-1 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Allegro MicroSystems
- Series:
- -
- Package/Case:
- 10-WFDFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Fixed
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 4V
- Voltage - Input (Max):
- 35V
- Voltage - Output (Min/Fixed):
- 3.3V
- Voltage - Output (Max):
- -
- Current - Output:
- 2A
- Frequency - Switching:
- 300kHz ~ 2MHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 150°C (TA)
- Grade:
- Automotive
- Qualification:
- AEC-Q100
- Mounting Type:
- Surface Mount, Wettable Flank
- Supplier Device Package:
- 10-DFN (3x3)
A8591KEJTR-J-1 FAQ
1.How can I place an order for A8591KEJTR-J-1 through Aetrix?
Please submit a Request for Quotation (RFQ) for A8591KEJTR-J-1 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 A8591KEJTR-J-1 reliable?
The price and inventory of A8591KEJTR-J-1 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for A8591KEJTR-J-1 is usually 5 days.
3.What payment methods are accepted for A8591KEJTR-J-1?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for A8591KEJTR-J-1 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for A8591KEJTR-J-1?
A8591KEJTR-J-1 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your A8591KEJTR-J-1 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 A8591KEJTR-J-1?
For technical support, including A8591KEJTR-J-1 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your A8591KEJTR-J-1 requirements.
6.How does Aetrix verify that A8591KEJTR-J-1 is sourced from the original manufacturer or authorized distributors?
All A8591KEJTR-J-1 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 A8591KEJTR-J-1 meets industry standards.
7.What is the process for return or replacement of A8591KEJTR-J-1?
All A8591KEJTR-J-1 units undergo pre-shipment inspection (PSI). If there is an issue with A8591KEJTR-J-1, 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 A8591KEJTR-J-1 part is unused and in its original packaging.
Return procedure for A8591KEJTR-J-1:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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