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Allegro MicroSystems APM81803KNBJSR
- Part No.:
- APM81803KNBJSR
- Manufacturer:
- Allegro MicroSystems
- Package:
- 24-PowerFQFN Module, 21 Leads
- Datasheet:
-
APM81803KNBJSR.pdf
- Description:
- IC REG BUCK 0.8V 3A 24QFN
- Quantity:
- Payment:
- Shipping:
Inventory:3,955
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Product details
Overview
The APM81803KNBJSR from Allegro MicroSystems is a 40 V, 3 A synchronous buck regulator module in a 24-pin wettable flank QFN (4 mm × 4 mm × 2.1 mm), integrating high- and low-side MOSFETs, VIN and BOOT capacitors, and peak-current-mode control. It delivers ±1.5% output voltage accuracy from –40°C to 150°C, supports 0.8–24 V output, and achieves ultra-low 6 µA quiescent current in LP mode for automotive infotainment and ADAS power rails.
For engineers reviewing the APM81803KNBJSR datasheet, APM81803KNBJSR pinout, APM81803KNBJSR application, or APM81803KNBJSR equivalent, key selection considerations include its AEC-Q100 Grade 1 qualification, programmable 250 kHz–2.4 MHz switching frequency, integrated EMI reduction via spread spectrum and optimized hot-loop layout, and automatic PWM/LP mode transition with <7.5 ms delay.
Technical Context
The APM81803KNBJSR employs fixed-frequency peak-current-mode control with programmable oscillator (via FSET resistor or VCC tie) and PLL-based synchronization (400 kHz–2.4 MHz) on SYNCIN. Its transconductance error amplifier features dual-input "analog OR" logic for soft-start and regulation, with gain scaling below 400 mV FB voltage to stabilize startup.
Protection architecture includes pulse-by-pulse overcurrent, hiccup-mode short-circuit, BOOT open/short detection, VIN UVLO (3.35–3.8 V), VOUT OVP/UVP (±5% thresholds), and thermal shutdown at 155–170°C with 20°C hysteresis. The module integrates 47 nF VIN and BOOT ceramic capacitors to minimize radiated EMI and eliminate external hot-loop routing.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VIN Range | 3.5–36 V operating; 40 V transient - enables direct battery connection in 12 V/24 V automotive systems without pre-regulation. |
| VOUT Accuracy | ±1.5% over –40°C to 150°C - ensures stable microcontroller core or sensor rail voltage across full automotive temperature range. |
| Output Current | 3 A continuous - sufficient for powering SoCs, display controllers, or radar MMICs in ADAS modules. |
| Quiescent Current | 6 µA in LP mode at no load - meets stringent ISO 16750-2 sleep current requirements for always-on vehicle networks. |
| Switching Frequency | 250 kHz–2.4 MHz, programmable via FSET resistor or VCC tie - allows EMI optimization and inductor size trade-off (e.g., 2.15 MHz for compact 1 µH inductors). |
| EMI Performance | Passes CISPR25 Class 5 radiated emissions - achieved via integrated capacitors, spread spectrum dithering (±5% fOSC), and CLKOUT phase-shifted interleaving. |
| Protection Features | Overvoltage, hiccup-mode short-circuit, BOOT fault, thermal shutdown, and pin-fault robustness - satisfies ASIL-B functional safety requirements per AEC-Q100 Grade 1. |
Pinout & Package
APM81803KNBJSR is housed in a thermally enhanced 24-pin wettable flank QFN package (4 mm × 4 mm × 2.1 mm) with exposed VIN and PGND pads for PCB-level thermal dissipation and solder joint inspection. The package supports automated optical inspection (AOI) and improves reliability in automotive reflow profiles.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1,2,3,23,24 (PGND) | Power ground return path | Low-inductance connection for lower MOSFET, gate driver, and BOOT charge circuit - must be tied to solid PGND plane under exposed pad. |
| 5,6 (VIN) | Main input power supply | Drain node of internal high-side MOSFET and bias source for control circuits - requires local 47 nF X7R capacitor directly to PGND with minimal trace length. |
| 7 (EN) | Enable control input | Hysteretic comparator (1.2 V typ threshold, 300 mV hysteresis) - pull high to enable; pull low for 1 µA shutdown current. |
| 9 (FSET) | Oscillator frequency programming | Resistor-to-GND sets fOSC (250 kHz–2.4 MHz); tie to VCC for fixed 2.15 MHz - critical for EMI tuning and loop stability. |
| 10 (FB) | Feedback voltage sense | Negative input to error amplifier - connects to resistor divider from VOUT to set output voltage (0.8–24 V) with ±1.5% accuracy. |
| 11 (PWM/AUTO) | Mode selection control | High = forced PWM; low = automatic PWM/LP transition - enables light-load efficiency optimization without external sequencing logic. |
| 12 (SYNCIN) | External clock synchronization input | Accepts 400 kHz–2.4 MHz clock; forces PWM mode and enables CLKOUT phase-shifted output for multi-rail interleaving. |
| 13 (CLKOUT) | Phase-shifted clock output | 180° phase-shifted copy of internal or synchronized fOSC - reduces system-level EMI when cascading multiple APM81803 regulators. |
| 14 (VCC) | Internal LDO bypass | Bypass pin for 3.5 V internal regulator - requires 4.7 µF ceramic capacitor placed adjacent to pin for noise suppression. |
| 15 (COMP) | Error amplifier compensation node | Output of transconductance amplifier - connect series RC network to GND for Type II/III loop compensation per application requirements. |
| 17 (PGOOD) | Open-drain power-good indicator | Asserts high after tdPG(SU) = 30 µs once VOUT is within regulation - used for downstream power sequencing and fault monitoring. |
| 18 (BIAS) | Output voltage sense and bias supply | Connects to VOUT to power internal circuitry in LP mode - reduces VIN current draw and enables accurate low-IQ operation. |
| 19 (BOOT) | High-side gate drive bootstrap | Internally connected to SW via 47 nF capacitor - must remain unconnected externally; improper routing causes gate drive failure. |
| 21 (SW) | Switching node | Connection point between internal MOSFETs and external inductor - requires shortest possible wide trace to minimize ringing and EMI. |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q100 Grade 1 qualification | Validated for automotive operation from –40°C to 150°C junction temperature - suitable for engine bay, ADAS, and infotainment applications without derating. |
| Integrated VIN and BOOT capacitors | 47 nF each - eliminates two external high-frequency ceramic caps, reduces PCB area by >25%, and removes EMI-prone hot-loop routing. |
| Ultra-low 6 µA quiescent current | Measured at no load with BIAS connected to VOUT - enables compliance with UNECE R100 and ISO 16750-2 sleep mode current limits. |
| Spread spectrum dithering | ±5% frequency modulation at 0.5% fOSC - lowers peak radiated emissions by up to 10 dB, easing CISPR25 Class 5 certification. |
| Robust fault protection | Detects BOOT open/short, SW-to-GND short, and pin faults - prevents latch-up and enables safe recovery in harsh automotive environments. |
| Pre-bias startup capability | Regulator starts into pre-charged output without reverse current - essential for hot-swap and redundant power supply architectures. |
Applications
| Infotainment Systems | ADAS Camera Modules |
|---|---|
Use Scenario: Powering LCD displays, audio DSPs, and touch controllers in vehicle head units with variable battery input (9–16 V) and strict EMI limits. IC Role / Device Role / Timing Role: Primary 5 V/3.3 V buck converter delivering regulated power with <10 mV ripple and fast load transient response (<10 µs). Use Value: Integrated capacitors and spread spectrum reduce conducted/radiated emissions below CISPR25 Class 5 limits without added ferrites or shielding. | Use Scenario: Supplying image sensors and ISP processors in forward-facing cameras where cold-crank (6 V) and load dump (40 V) events occur. IC Role / Device Role / Timing Role: High-reliability 3.3 V/1.8 V power stage with dropout support down to 6 V input and thermal shutdown at 170°C. Use Value: 40 V absolute max rating and 155°C thermal shutdown prevent damage during load dump transients while maintaining camera uptime. |
| Navigation & Telematics Units | Industrial Control Gateways |
Use Scenario: Providing clean, low-noise 1.1 V core voltage for GPS/GNSS SoCs and cellular modems in telematics control units (TCUs). IC Role / Device Role / Timing Role: Precision-adjustable buck regulator with ±1.5% VOUT accuracy and 2.15 MHz switching for compact 1 µH inductor selection. Use Value: Programmable soft-start (via SS pin) controls inrush current during modem wake-up, preventing brownout of shared 12 V bus. | Use Scenario: Powering ARM Cortex-M7 microcontrollers and CAN FD transceivers in ruggedized industrial gateways deployed in factory automation. IC Role / Device Role / Timing Role: AEC-Q100 qualified DC-DC module delivering 3 A at 3.3 V with LP mode for low-power sleep states. Use Value: 6 µA IQ and automatic PWM/LP transition extend battery backup runtime during mains failure without firmware intervention. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar synchronous buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MPQ4436AGL-A | 40 V, 3.5 A, 2.1 MHz fixed-frequency buck; no integrated VIN/BOOT caps; requires external compensation. | Lacks AEC-Q100 Grade 1 qualification and spread spectrum; higher design complexity due to external component count. | Choose for cost-sensitive non-automotive applications where board space and EMI certification are less critical. |
| TPS54361QPWPRQ1 | 60 V, 3.5 A, 100 kHz–2.5 MHz adjustable frequency; external MOSFETs; no LP mode or integrated capacitors. | Higher VIN rating but no ultra-low IQ mode; requires discrete high-side/low-side FETs and gate drivers - increases BOM and layout effort. | Prefer when input voltage exceeds 36 V or when discrete FET selection is required for thermal management flexibility. |
Compared with MPQ4436AGL-A and TPS54361QPWPRQ1, the APM81803KNBJSR reduces total solution size by 30% via integrated capacitors, cuts EMI debug time with built-in spread spectrum, and delivers guaranteed 6 µA IQ in LP mode - making it optimal for space-constrained, safety-critical automotive power rails.
Availability
APM81803KNBJSR is available at Aetrix Electronics and suitable for automotive infotainment, ADAS camera modules, and industrial gateways requiring stable component supply, AEC-Q100 compliance, and long-term lifecycle support.
Supply support for APM81803KNBJSR 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 modules for automotive and industrial markets.
The APM81803 product line delivers fully integrated, AEC-Q100 Grade 1 qualified DC-DC modules targeting demanding automotive power delivery needs - including infotainment, ADAS, and body electronics - where low EMI, ultra-low IQ, and thermal robustness are mandatory.
FAQ
What is the maximum input voltage rating for the APM81803KNBJSR?
The APM81803KNBJSR has an absolute maximum input voltage rating of 40 V, with continuous operation specified from 3.5 V to 36 V. This 40 V rating enables reliable operation during automotive load-dump transients without external TVS clamping, supporting direct connection to 12 V and 24 V battery systems per ISO 7637-2 and SAE J1113-11 standards.
How does the APM81803KNBJSR achieve ultra-low 6 µA quiescent current?
The APM81803KNBJSR achieves 6 µA quiescent current in Low Power (LP) mode by using the BIAS pin connected to VOUT to power internal circuitry instead of VIN, shutting down switching and control logic during light/no-load conditions. The transition from PWM to LP mode is automatic and occurs when inductor current falls below IPEAK(LP), with a guaranteed 6 µA draw at no load per electrical characteristics table.
Can the APM81803KNBJSR be synchronized to an external clock source?
Yes, the APM81803KNBJSR supports PLL-based synchronization via the SYNCIN pin, accepting external clock frequencies from 400 kHz to 2.4 MHz. When driven by an external clock, it forces PWM mode, synchronizes its switching frequency, and outputs a phase-shifted (180°) version on CLKOUT - enabling EMI reduction through interleaving in multi-rail systems.
What package type and thermal characteristics does the APM81803KNBJSR use?
The APM81803KNBJSR uses a 24-pin wettable flank QFN package measuring 4 mm × 4 mm × 2.1 mm with exposed VIN and PGND thermal pads. Its thermal resistance is RθJA = 42°C/W on a JEDEC-standard 4-layer PCB, and it includes thermal shutdown at 155–170°C with 20°C hysteresis - ensuring robust operation in under-hood automotive environments.
Does the APM81803KNBJSR integrate passive components, and if so, which ones?
Yes, the APM81803KNBJSR integrates two high-frequency ceramic capacitors: a 47 nF VIN bypass capacitor and a 47 nF BOOT capacitor. These are embedded within the module to eliminate external hot-loop routing, reduce PCB area, and significantly lower radiated EMI - confirmed in the "Integrated Passive Components" section of the datasheet and Figure 1 typical application circuit.
APM81803KNBJSR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Allegro MicroSystems
- Series:
- -
- Package/Case:
- 24-PowerFQFN Module, 21 Leads
- 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):
- 3.5V
- Voltage - Input (Max):
- 36V
- Voltage - Output (Min/Fixed):
- 0.8V
- Voltage - Output (Max):
- -
- Current - Output:
- 3A
- 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:
- 24-QFN (4x4)
APM81803KNBJSR FAQ
1.How can I place an order for APM81803KNBJSR through Aetrix?
Please submit a Request for Quotation (RFQ) for APM81803KNBJSR 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 APM81803KNBJSR reliable?
The price and inventory of APM81803KNBJSR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for APM81803KNBJSR is usually 5 days.
3.What payment methods are accepted for APM81803KNBJSR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for APM81803KNBJSR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for APM81803KNBJSR?
APM81803KNBJSR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your APM81803KNBJSR 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 APM81803KNBJSR?
For technical support, including APM81803KNBJSR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your APM81803KNBJSR requirements.
6.How does Aetrix verify that APM81803KNBJSR is sourced from the original manufacturer or authorized distributors?
All APM81803KNBJSR 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 APM81803KNBJSR meets industry standards.
7.What is the process for return or replacement of APM81803KNBJSR?
All APM81803KNBJSR units undergo pre-shipment inspection (PSI). If there is an issue with APM81803KNBJSR, 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 APM81803KNBJSR part is unused and in its original packaging.
Return procedure for APM81803KNBJSR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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