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Allegro MicroSystems A8591KEJTR-J
- Part No.:
- A8591KEJTR-J
- Manufacturer:
- Allegro MicroSystems
- Package:
- 10-WFDFN Exposed Pad
- Datasheet:
-
A8591KEJTR-J.pdf
- Description:
- IC REG BUCK 5V 2A 10DFN
- Quantity:
- Payment:
- Shipping:
Inventory:2,033
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Product details
Overview
A8591KEJTR-J from Allegro MicroSystems is a wide-input, 2 A automotive-grade buck regulator with integrated 110 mΩ high-side MOSFET, ±1% output voltage accuracy at 5 V, pulse-frequency modulation (PFM) low-IQ mode (<10 µA sleep current), and AEC-Q100 qualification - designed for car audio power rails in instrument clusters and infotainment systems.
For engineers reviewing the A8591KEJTR-J datasheet, A8591KEJTR-J pinout, A8591KEJTR-J application, or A8591KEJTR-J equivalent, key selection considerations include its 4–35 V input range, 300 kHz–2.4 MHz adjustable switching frequency, external compensation for stability tuning, NPOR output with 7.5 ms delay, and wettable-flank DFN-10 thermal package for automotive thermal reliability.
Technical Context
The A8591KEJTR-J implements current-mode control with transconductance error amplifier (gm = 88–152 µA/V), slope compensation, and pulse-by-pulse overcurrent protection. Its dual-mode operation switches automatically between PWM (up to 2 A) and low-IQ PFM (≤33 µA at 5 V/40 µA load) based on output current demand.
It features programmable frequency via RFSET resistor, external synchronization capability (0.375–2.4 MHz), BOOT voltage regulation with open/short protection, and pre-bias startup with monotonic VOUT ramp. The device supports dropout operation down to 3.6 VIN and withstands 40 V load-dump surges.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 5 V ±1% accuracy across –40°C to 150°C junction temperature - ensures stable MCU/SoC core rail under automotive thermal stress. |
| Max Output Current | 2 A continuous - sufficient for powering DSPs, amplifiers, and display controllers in head units without external boost stages. |
| Input Voltage Range | 4 V to 35 V - accommodates cold-crank (4 V), normal operation (12–14 V), and load-dump (up to 40 V transient) per ISO 7637-2. |
| Quiescent Current | 10 µA in Sleep mode (EN/SLEEP = low) - enables always-on subsystems with <1 µW standby power draw. |
| Switching Frequency | Adjustable 300 kHz to 2.4 MHz via RFSET - allows EMI optimization and inductor size reduction while supporting external clock sync. |
| Thermal Package | 10-pin 3 × 3 mm wettable-flank DFN with exposed thermal pad (RθJA = 45°C/W on 4-layer JEDEC board) - delivers robust thermal performance in confined automotive PCB layouts. |
| Protection Features | Pulse-by-pulse current limit, hiccup-mode short-circuit, BOOT fault detection, VIN UVLO (3.6 V start), and thermal shutdown (170°C trip) - ensures fail-safe operation in harsh environments. |
Pinout & Package
Package: 10-pin, 3 × 3 mm wettable-flank DFN with exposed thermal pad (EJ suffix), lead-free, 100% matte tin plating - optimized for automated optical inspection (AOI) and thermal reliability in automotive reflow profiles.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 2 - VIN | Power input for control circuitry 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. |
| 3 - EN/SLEEP | Enable and ultralow-power sleep control input | Logic-high (>2.1 V) enables regulation; logic-low forces shutdown with <15 µA IIN; internal 224 µs debounce prevents false sleep triggers. |
| 4 - FSET/SYNCPWM | Frequency setting and external clock synchronization input | Resistor-to-GND sets fSW (300 kHz–2.4 MHz); external clock forces PWM mode and disables dithering - critical for EMI-sensitive infotainment stacks. |
| 5 - VOUT | Regulated 5 V output and internal feedback node | Connects to on-chip 4× resistor divider for 800 mV error amp reference; requires Kelvin routing to maintain ±1% accuracy under load transients. |
| 6 - NPOR | Active-low power-on reset output | Open-drain signal asserts low until VOUT reaches regulation, then releases after 7.5 ms delay - provides deterministic system reset timing for microcontrollers. |
| 7 - COMP | Error amplifier output and loop compensation node | External RZ/CZ/CP network sets phase margin and transient response - enables stable operation with ceramic or electrolytic output capacitors. |
| 8 - GND | Analog and power ground reference | Shared return path for control circuitry; must be connected to thermal pad vias and low-impedance ground plane to minimize noise coupling. |
| 9 - SW | Switch node connecting internal high-side MOSFET source and external inductor/diode | High dv/dt node requiring short, wide traces; connects to LO and D1 - layout directly impacts efficiency and EMI performance. |
| 10 - BOOT | High-side gate drive bootstrap supply | 47 nF ceramic capacitor from BOOT to SW supplies gate drive; open/short detection prevents shoot-through and ensures reliable MOSFET turn-on. |
| Pad - Exposed Thermal Pad | Primary thermal conduction path to PCB | Must be soldered to solid ground plane with ≥6 thermal vias - accounts for >70% of total heat dissipation in high-current operation. |
Key Features
| Feature | Design Value |
|---|---|
| Low-IQ PFM Mode | Draws only 28–33 µA at 12 VIN/5 VOUT/40 µA load - extends battery life in parked-state audio memory and Bluetooth modules. |
| EMI Reduction Suite | Includes frequency dithering (±7.5%), controlled SW node slew rate (0.72 V/ns), and external sync - meets CISPR-25 Class 5 requirements without added shielding. |
| Pre-Biased Startup | VOUT ramps monotonically from pre-charged state - prevents system resets during hot-plug or brown-out recovery in navigation systems. |
| Automotive Qualification | AEC-Q100 Grade 1 (–40°C to +125°C ambient / –40°C to +150°C junction) - validated for under-hood and dashboard mounting locations. |
| Load-Dump Robustness | Withstands 40 V transients per ISO 7637-2 Pulse 5a - eliminates need for external TVS diodes in cost-sensitive head unit designs. |
| Maximum Duty Cycle Support | Enables operation down to 3.6 VIN at 5 VOUT - sustains audio processor power during engine cranking without brownout. |
Applications
| Instrument Clusters | Car Audio Amplifiers |
|---|---|
Use Scenario: Powering digital gauges, TFT displays, and CAN interface ICs in modern digital dashboards. IC Role / Device Role / Timing Role: Primary 5 V buck regulator supplying microcontroller, graphics processor, and sensor interface rails. Use Value: Delivers stable 5 V ±1% under cold-crank (4 VIN) and load-dump (40 VIN) conditions - ensures uninterrupted display rendering and CAN communication. |
Use Scenario: Generating clean 5 V bias for Class D amplifier controllers and DSPs in OEM head units. IC Role / Device Role / Timing Role: High-efficiency, low-noise DC-DC stage preceding audio signal chain power domains. Use Value: Low-IQ PFM mode reduces quiescent loss during silent playback; EMI features prevent audible switching noise in analog audio paths. |
| Infotainment Head Units | HVAC Control Modules |
Use Scenario: Supplying 5 V to navigation SoCs, Wi-Fi/BT modems, and touch controller ICs in center-stack systems. IC Role / Device Role / Timing Role: Main system power rail with NPOR-synchronized boot sequencing for multi-core processors. Use Value: 7.5 ms NPOR delay aligns with SoC reset timing; external sync capability enables clock domain coherency with display and audio subsystems. |
Use Scenario: Providing regulated 5 V for HVAC microcontrollers, motor drivers, and cabin sensor interfaces. IC Role / Device Role / Timing Role: Robust point-of-load regulator tolerant to battery voltage fluctuations during blower motor startup. Use Value: 2 A current capacity supports simultaneous actuation of multiple stepper motors; thermal pad ensures reliability in enclosed HVAC housing. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MPQ4420AGL-AEC1-Z | 4–36 V input, 2 A, fixed 5 V, no PFM mode, 25 µA no-load IQ, AEC-Q100 Grade 1 | Lacks low-IQ PFM and external sync; higher no-load IQ increases parked-state battery drain | Choose when EMI sync and ultra-low standby power are not required; simpler BOM with integrated compensation. |
| TPS54202HDDCR | 4.5–28 V input, 2 A, adjustable output, 25 µA IQ, no AEC-Q100, no load-dump rating | Non-automotive grade; lacks 40 V surge tolerance and thermal derating data for automotive ambient | Consider only for non-automotive industrial audio systems where qualification and surge immunity are not mandated. |
Compared with MPQ4420AGL-AEC1-Z and TPS54202HDDCR, the A8591KEJTR-J uniquely combines AEC-Q100 Grade 1 qualification, 40 V load-dump resilience, <10 µA sleep current, and external clock synchronization - making it the only option qualified for safety-critical infotainment power rails requiring deterministic timing and zero-battery-drain parking modes.
Availability
A8591KEJTR-J is available at Aetrix Electronics and suitable for automotive instrument clusters, car audio amplifiers, and infotainment head units requiring stable component supply with full AEC-Q100 traceability and long-term production support.
Supply support for A8591KEJTR-J 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 and industrial applications.
The A8591 family is part of Allegro's automotive power management portfolio, engineered specifically for next-generation car audio and infotainment systems demanding high efficiency, ultra-low standby power, and robust transient immunity.
FAQ
What is the maximum input voltage the A8591KEJTR-J can withstand during load dump events?
The A8591KEJTR-J is rated to withstand 40 V input transients per ISO 7637-2 Pulse 5a, enabling direct connection to automotive battery rails without external TVS diodes. This surge rating is verified per AEC-Q100 stress testing and applies across the full –40°C to +150°C junction temperature range. The device enters hiccup-mode protection if sustained overvoltage exceeds absolute maximum ratings, ensuring safe operation during real-world load-dump scenarios encountered in vehicle electrical systems. A8591KEJTR-J maintains this capability without derating or additional external components.
Does the A8591KEJTR-J support pre-biased startup, and how does it behave when VOUT is initially charged?
Yes, the A8591KEJTR-J supports pre-biased startup: when enabled with a pre-charged VOUT, the output voltage increases monotonically without droop or reversal, preventing unintended system resets. This behavior is achieved through internal circuitry that disables the high-side MOSFET until the error amplifier detects rising feedback voltage, eliminating inrush current conflicts. The feature is confirmed in the Functional Block Diagram and validated across –40°C to +150°C. A8591KEJTR-J guarantees monotonic ramp regardless of initial VOUT voltage, making it suitable for hot-plug and brown-out recovery in infotainment modules.
What is the exact switching frequency range of the A8591KEJTR-J, and how is it set?
The A8591KEJTR-J supports an adjustable PWM switching frequency from 300 kHz to 2.4 MHz, set by an external resistor (RFSET) connected from the FSET/SYNCPWM pin to GND. Specific values include 300 kHz (RFSET = 86.6 kΩ), 415 kHz (61.9 kΩ), and 2 MHz (9.31 kΩ), with ±10% tolerance over temperature. Frequency dithering (±7.5%) is enabled by default to reduce EMI peaks but disabled during external clock synchronization. A8591KEJTR-J maintains stable operation across this full range with proper external compensation, as verified in the Electrical Characteristics table and Characteristic Performance plots.
How does the A8591KEJTR-J manage thermal performance in automotive environments?
The A8591KEJTR-J uses a thermally enhanced 3 × 3 mm wettable-flank DFN package with an exposed pad connected to PCB ground via ≥6 vias, achieving 45°C/W junction-to-ambient thermal resistance on a 4-layer JEDEC board. It incorporates thermal shutdown at 170°C (with 20°C hysteresis) and derates output current based on ambient temperature, airflow, and PCB layout - documented in Figure 3 of the datasheet. A8591KEJTR-J operates continuously from –40°C to +150°C junction temperature, meeting AEC-Q100 Grade 1 requirements for under-dash and under-hood placements without forced cooling.
Is the A8591KEJTR-J pin-compatible with the A8591KEJTR-J-1 variant?
No, the A8591KEJTR-J (5 V fixed) and A8591KEJTR-J-1 (3.3 V fixed) are not pin-compatible due to different internal feedback dividers and NPOR threshold voltages - though they share identical pinout, package, and functional architecture. Swapping them requires updating the NPOR monitoring circuit and verifying system-level reset timing, as VNPORUV and VNPOROV thresholds differ by ~1.5 V between variants. A8591KEJTR-J must be used only in 5 V rail designs; substitution with the -1 variant will cause incorrect power-on reset assertion and potential system instability.
A8591KEJTR-J 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):
- 5V
- 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 FAQ
1.How can I place an order for A8591KEJTR-J through Aetrix?
Please submit a Request for Quotation (RFQ) for A8591KEJTR-J 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 reliable?
The price and inventory of A8591KEJTR-J 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 is usually 5 days.
3.What payment methods are accepted for A8591KEJTR-J?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for A8591KEJTR-J transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for A8591KEJTR-J?
A8591KEJTR-J orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your A8591KEJTR-J 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?
For technical support, including A8591KEJTR-J datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your A8591KEJTR-J requirements.
6.How does Aetrix verify that A8591KEJTR-J is sourced from the original manufacturer or authorized distributors?
All A8591KEJTR-J 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 meets industry standards.
7.What is the process for return or replacement of A8591KEJTR-J?
All A8591KEJTR-J units undergo pre-shipment inspection (PSI). If there is an issue with A8591KEJTR-J, 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 part is unused and in its original packaging.
Return procedure for A8591KEJTR-J:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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