My Inquiry
My Account
Allegro MicroSystems ARG81800KESJSR
- Part No.:
- ARG81800KESJSR
- Manufacturer:
- Allegro MicroSystems
- Package:
- 20-WFQFN Exposed Pad
- Datasheet:
-
ARG81800KESJSR.pdf
- Description:
- IC REG BUCK ADJ 1A 20QFN
- Quantity:
- Payment:
- Shipping:
Inventory:11,904
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
ARG81800KESJSR from Allegro MicroSystems is a 40 V, 1 A synchronous buck regulator with ultralow quiescent current (8 µA in LP mode), ±1.5% output voltage accuracy over –40°C to 150°C, and programmable switching frequency from 250 kHz to 2.4 MHz. It integrates SYNCIN/CLKOUT for EMI-reducing dithering and interleaving, supports pre-bias startup, and delivers robust protection including hiccup-mode OCP, thermal shutdown, and BOOT fault detection - designed for automotive infotainment and ADAS power rails.
For engineers reviewing the ARG81800KESJSR datasheet, ARG81800KESJSR pinout, ARG81800KESJSR application, or ARG81800KESJSR equivalent, key selection considerations include its AEC-Q100 qualification, wettable-flank 20-pin QFN package, 3.5–36 V input range, adjustable soft-start, external compensation flexibility, and dual-mode (PWM/AUTO) operation enabling ultra-low-IQ keep-alive supply functionality.
Technical Context
The ARG81800KESJSR implements current-mode PWM control with slope compensation, transconductance error amplifier (750 µA/V typ.), and programmable oscillator via FSET resistor. Its dual operating modes-forced PWM and AUTO (PWM ↔ Low-Power transition)-are controlled by the PWM/AUTO pin and load-current threshold (400 mA typ. for LP exit).
It features integrated synchronization logic: SYNCIN accepts external clocks (0.25–2.5 MHz) to force PWM mode and trigger CLKOUT dithering; CLKOUT provides phase-shifted, dithered clock for downstream regulator interleaving. Dropout recovery uses frequency foldback (fSW/4), and soft-start is capacitor-programmable (22 nF → 880 µs ramp).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3.5 V to 36 V - supports automotive battery systems including 12 V and 24 V rails; withstands 40 V load-dump surges. |
| Output Current | 1 A continuous - validated for ARG81800KESJSR variant; enables compact PCB layout vs. 500 mA version. |
| Quiescent Current (LP Mode) | 8 µA at 3.3 V/5.0 V out - sustains "keepalive" supply during vehicle sleep mode without draining battery. |
| Switching Frequency Range | 250 kHz to 2.4 MHz - set via FSET resistor; allows optimization of efficiency, inductor size, and EMC performance. |
| Output Voltage Accuracy | ±1.5% over –40°C to 150°C - ensures stable regulation across full automotive temperature range. |
| Protection Features | Pulse-by-pulse current limit, hiccup-mode short-circuit, BOOT open/short, VIN UVLO, VOUT OVP/UVP, thermal shutdown - meets ASIL-B functional safety requirements. |
| Package | 20-pin, 4 mm × 4 mm wettable-flank QFN (ES) with exposed thermal pad - enables automated optical inspection (AOI) and enhanced thermal dissipation (RθJA = 37 °C/W). |
Pinout & Package
ARG81800KESJSR is housed in a 20-pin, 4 mm × 4 mm wettable-flank QFN (ES) package with exposed thermal pad. The package supports solder joint inspection and delivers low thermal resistance (37 °C/W on 4-layer JEDEC board).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1: BOOT | High-side gate driver supply | Connects 100 nF ceramic capacitor to SW; no series resistor allowed - critical for reliable high-side MOSFET turn-on. |
| 2,3: SW | Power switch node | Direct connection point to power inductor; requires short, wide PCB trace to minimize parasitic inductance and EMI. |
| 4: SS | Soft-start timing | Capacitor-to-GND sets startup ramp time (e.g., 22 nF → 880 µs) and hiccup period - controls inrush current into large output caps. |
| 5: EN | Enable control | Logic-high enables regulation; logic-low forces 1 µA shutdown with VOUT = 0 V - supports system-level power sequencing. |
| 6: CLKOUT | Synchronization clock output | Provides dithered, phase-shifted clock for interleaving downstream regulators - reduces input ripple and improves EMI signature. |
| 7: SYNCIN | External clock input | Accepts 0.25–2.5 MHz external clock to force PWM mode and synchronize switching - enables deterministic EMI reduction. |
| 8: GND | Analog ground reference | Separate from PGND; must be routed with low-impedance path to minimize noise coupling into feedback and control circuits. |
| 9: FSET | Oscillator frequency setting | Resistor-to-GND (e.g., 14.3 kΩ) programs fSW = 2.15 MHz - enables precise trade-off between efficiency and component size. |
| 10: PWM/AUTO | Mode selection control | High = forced PWM; low = automatic transition between PWM and LP based on load - eliminates manual mode management. |
| 11: COMP | Error amplifier output | External RC network (RZ, CZ, CP) sets loop stability and transient response - supports tuning for fast load steps or high PSRR. |
| 12: PGOOD | Power-good status | Open-drain output with 30 µs startup delay; pulls low if VFB falls outside 740–880 mV window - enables safe system power-up sequencing. |
| 13: BIAS | Internal bias supply | Connected to VOUT; powers internal circuitry when VOUT ≥ 3.3 V - improves light-load efficiency vs. VIN-derived bias. |
| 14: FB | Feedback input | Resistor divider from VOUT sets regulated voltage; 800 mV reference enables 3.3 V, 5.0 V, or custom outputs with ±1.5% accuracy. |
| 15: VREG | Internal LDO bypass | 4.7 µF ceramic cap to PGND stabilizes internal 4.8 V regulator - essential for gate drive and analog circuit integrity. |
| 16,17: PGND | Power ground return | Low-impedance return path for low-side MOSFET, BOOT charge circuit, and SW node - must connect directly to thermal pad vias. |
| 18: NC | No connection | Unbonded pin - must remain unconnected and unpopulated on PCB. |
| 19,20: VIN | Main power input | Supplies control circuitry and high-side MOSFET drain; requires local X7R/X8R ceramic bypass (≥1 µF) near pins 19/20. |
| PAD | Thermal pad | Exposed copper pad under package; must connect to PCB ground plane via ≥6 thermal vias - primary path for heat dissipation. |
Key Features
| Feature | Design Value |
|---|---|
| Ultralow quiescent current (8 µA) | Enables always-on "keepalive" supplies in automotive modules without compromising battery life during extended sleep cycles. |
| Programmable frequency dithering | Reduces peak EMI amplitude by spreading energy across ±5% bandwidth - simplifies compliance with CISPR 25 Class 5 radiated emissions limits. |
| Interleavable CLKOUT with phase shift | Allows synchronized, phase-offset switching of multiple downstream converters - cuts input capacitor RMS current by up to 30% and lowers EMI. |
| Pre-bias startup capability | Permits safe restart into pre-charged output rails - avoids reverse current flow and system resets during hot-plug or brownout recovery. |
| External compensation network | Supports full loop tuning for either fast transient response (e.g., CPU core rail) or high PSRR (e.g., ADC reference supply) without changing IC. |
| AEC-Q100 Grade 0 qualification | Validated for operation from –40°C to +150°C junction temperature - suitable for under-hood and instrument cluster applications. |
Applications
| Infotainment Power Rail | ADAS Camera Module Supply |
|---|---|
|
Use Scenario: Powers SoC, display controller, and audio codec in automotive head units requiring stable 3.3 V/5.0 V during engine start-stop cycles and RF-heavy environments. IC Role / Device Role / Timing Role: Primary DC-DC converter delivering 1 A at ±1.5% accuracy; uses CLKOUT to synchronize secondary regulators for noise-sensitive audio paths. Use Value: 8 µA LP mode extends battery runtime during vehicle off-state; dithering and interleaving meet strict CISPR 25 radiated emissions limits. |
Use Scenario: Supplies image sensor and ISP in forward-facing ADAS cameras where thermal constraints and EMI immunity are critical. IC Role / Device Role / Timing Role: High-efficiency buck regulator with pre-bias startup and soft recovery from dropout - maintains clean power during cold cranking (VIN dips to 6 V). Use Value: 37 °C/W thermal resistance and wettable flank package enable reliable operation at 150°C junction; hiccup-mode OCP prevents thermal runaway during lens heater faults. |
| Instrument Cluster Display Backlight | Telematics Control Unit (TCU) Core Rail |
|
Use Scenario: Provides adjustable 5.0 V output for LED backlight drivers in digital instrument clusters with variable brightness and dimming profiles. IC Role / Device Role / Timing Role: Regulator with programmable soft-start (via SS pin) and adjustable output voltage - prevents inrush-induced voltage droop during rapid brightness changes. Use Value: External compensation allows tuning for high PSRR (>60 dB @ 100 kHz), rejecting noise from CAN/LIN transceivers sharing same PCB ground. |
Use Scenario: Generates 1.2 V core supply for LTE/C-V2X modems in TCUs requiring low-noise, high-transient-response power under varying cellular signal loads. IC Role / Device Role / Timing Role: Synchronous buck with current-mode control and slope compensation - delivers <10 µs transient response to 500 mA load steps. Use Value: PWM/AUTO pin enables dynamic mode switching: PWM for active data transmission, LP mode during idle - reducing average system power by >40%. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar synchronous buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MPQ4420AGL-A | 2.5 A rating, fixed 500 kHz fSW, no CLKOUT/SYNCIN, 17 µA IQ in shutdown only | Lacks dithering, interleaving, and AEC-Q100 Grade 0 - suitable for non-automotive industrial use with higher current demand | Select when higher output current is required and EMI synchronization is not needed; verify thermal design for 2.5 A continuous load. |
| TPS54560BQPWPRQ1 | 3.5–60 V input, 5 A, 100 µA IQ in eco-mode, no LP mode below 8 µA, no CLKOUT | Higher IQ, no wettable flank package, no frequency dithering - targets cost-sensitive automotive body electronics | Choose for wider input range and higher current where ultra-low-IQ keepalive is not mandatory; confirm PCB AOI compatibility without wettable flanks. |
Compared with MPQ4420AGL-A and TPS54560BQPWPRQ1, ARG81800KESJSR uniquely combines AEC-Q100 Grade 0, 8 µA LP mode, CLKOUT dithering, and wettable-flank QFN - making it the only option qualified for safety-critical, EMI-sensitive, always-on automotive domains like ADAS and digital clusters.
Availability
ARG81800KESJSR is available at Aetrix Electronics and suitable for automotive infotainment, ADAS camera modules, and instrument cluster power systems requiring stable component supply, long-term lifecycle support, and AEC-Q100-compliant sourcing.
Supply support for ARG81800KESJSR 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 global leader in precision sensing and power ICs, specializing in magnetic sensors, motor drivers, and high-reliability power management solutions for automotive and industrial markets.
The ARG81800 product line was engineered specifically for automotive power conversion - emphasizing ultralow quiescent current, AEC-Q100 Grade 0 operation, EMI-aware synchronization, and robust fault protection in harsh environments.
FAQ
What is the maximum input voltage the ARG81800KESJSR can withstand during load dump events?
The ARG81800KESJSR is rated to withstand surge voltages up to 40 V during load dump conditions while operating within its 3.5–36 V nominal input range. This capability is explicitly specified in the Absolute Maximum Ratings table and validated per ISO 7637-2 Pulse 5a testing requirements for automotive applications. The device remains functional and protected without external TVS clamping under these transient conditions.
Does the ARG81800KESJSR support pre-bias startup, and how does it behave when enabled?
Yes, the ARG81800KESJSR supports pre-bias startup. When the output is already biased (e.g., from another regulator or residual charge), the device starts switching without forcing reverse current into the output capacitor. During startup, the internal control logic monitors the FB pin and gradually ramps the duty cycle via the SS pin capacitor - ensuring monotonic VOUT rise and preventing system resets in hot-plug scenarios.
How does the PWM/AUTO pin affect the operating mode of the ARG81800KESJSR?
The PWM/AUTO pin determines whether the ARG81800KESJSR operates in forced PWM mode (pin high) or automatic PWM/LP transition mode (pin low). In AUTO mode, the device dynamically switches to Low-Power mode below ~400 mA load current, reducing IQ to 8 µA; above that threshold, it seamlessly reverts to PWM mode. This pin enables system-level control over efficiency versus responsiveness trade-offs.
What is the purpose of the CLKOUT pin on the ARG81800KESJSR, and how is it used in multi-regulator systems?
The CLKOUT pin on the ARG81800KESJSR outputs a dithered, phase-shifted version of the internal switching clock. In multi-regulator systems, this signal drives the SYNCIN pins of downstream buck converters, enabling precise interleaving (e.g., 180° phase offset) and collective frequency dithering - which reduces input ripple RMS current and spreads EMI energy across a broader spectrum for easier EMC compliance.
What thermal performance can be expected from the ARG81800KESJSR in a standard 4-layer PCB layout?
In a JEDEC-standard 4-layer PCB layout, the ARG81800KESJSR achieves a junction-to-ambient thermal resistance (RθJA) of 37 °C/W. With its exposed thermal pad connected to the ground plane via ≥6 vias, the device sustains 1 A continuous output at ambient temperatures up to +85°C without derating - assuming typical airflow and no additional heatsinking. Full thermal calculations require validation using Allegro's published power dissipation models.
ARG81800KESJSR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Allegro MicroSystems
- Series:
- -
- Package/Case:
- 20-WFQFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 3.5V
- Voltage - Input (Max):
- 36V
- Voltage - Output (Min/Fixed):
- 0.8V
- Voltage - Output (Max):
- 36V
- Current - Output:
- 1A
- Frequency - Switching:
- 250kHz ~ 2.4MHz
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -40°C ~ 150°C (TJ)
- Grade:
- Automotive
- Qualification:
- AEC-Q100
- Mounting Type:
- Surface Mount, Wettable Flank
- Supplier Device Package:
- 20-QFN (4x4)
ARG81800KESJSR FAQ
1.How can I place an order for ARG81800KESJSR through Aetrix?
Please submit a Request for Quotation (RFQ) for ARG81800KESJSR 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 ARG81800KESJSR reliable?
The price and inventory of ARG81800KESJSR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for ARG81800KESJSR is usually 5 days.
3.What payment methods are accepted for ARG81800KESJSR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for ARG81800KESJSR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for ARG81800KESJSR?
ARG81800KESJSR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your ARG81800KESJSR 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 ARG81800KESJSR?
For technical support, including ARG81800KESJSR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your ARG81800KESJSR requirements.
6.How does Aetrix verify that ARG81800KESJSR is sourced from the original manufacturer or authorized distributors?
All ARG81800KESJSR 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 ARG81800KESJSR meets industry standards.
7.What is the process for return or replacement of ARG81800KESJSR?
All ARG81800KESJSR units undergo pre-shipment inspection (PSI). If there is an issue with ARG81800KESJSR, 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 ARG81800KESJSR part is unused and in its original packaging.
Return procedure for ARG81800KESJSR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
ARG81800KESJSR Tags
-
TPS562201DDCR
Texas Instruments
-
MC34063ABD-TR
STMicroelectronics
-
TPS561201DDCR
Texas Instruments
-
MC33063ADR
Texas Instruments
-
MC34063ADR
Texas Instruments
-
TPS560200DBVR
Texas Instruments
-
AP3012KTR-G1
Diodes Incorporated
-
TLV61048DBVR
Texas Instruments
-
AZ34063UMTR-G1
Diodes Incorporated
-
TPS562200DDCR
Texas Instruments
-
AP62300TWU-7
Diodes Incorporated
-
MC34063EBD-TR
STMicroelectronics
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…
