AOZ2261NQI-11 - 28V/8A Sync Buck Regulator QFN-23 | AOS
MPN: AOZ2261NQI-11 ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $1.42 | $1.42 |
| 10 | $1.28 | $12.80 |
| 100 | $1.05 | $105.00 |
| 500 | $0.84 | $420.00 |
| 1,000 | $0.68 | $680.00 |
| 3,000 | $0.49 | $1,470.00 |
AOZ2261NQI-11 Overview
A buck regulator (also called a step-down switching converter) is a type of DC/DC power converter that uses an inductor, a switch, and a rectifier to convert a higher input voltage to a lower output voltage with high efficiency. Synchronous buck regulators replace the traditional diode rectifier with a low-side MOSFET to reduce conduction loss, achieving efficiencies above 90 percent in most applications. Buck regulators belong to the voltage regulator family within the broader power management IC category, sitting architecturally between the input supply and downstream digital, analog, or RF loads.
Key features of the AOZ2261NQI-11 include a wide 0.6V to 23.8V adjustable output range, VCC under-voltage lockout, cycle-by-cycle current limit, output over-voltage protection, short-circuit protection, and thermal shutdown. Internal MOSFETs and a high switching frequency capability shrink the external LC filter footprint, while the exposed pad enables direct PCB heatsinking for full 8A operation.
The architecture uses constant on-time (COT) control for fast transient response and predictable loop behavior without external compensation. A 4mm x 4mm QFN-23L package with low thermal resistance allows continuous 8A delivery from nominal 12V inputs at moderate ambient temperatures.
Typical applications include notebook computer core and chipset rails, 12V distributed bus point-of-load converters, networking and telecom POL supplies, FPGA and SoC core rails, and high-current industrial 24V bus conversion. Designers choose this part for compact PCB area, high efficiency at moderate loads, and proven AlphaOmega EZBuck reliability.
Designers should size the input capacitor to handle the ripple current of the high-side FET, choose an inductor with low DCR and adequate saturation margin above 8A, and route the feedback trace away from switching nodes. The exposed pad must be soldered to a sufficiently large copper pour for thermal dissipation; without it the junction will overheat well before reaching 8A.
This page synthesizes distributor pricing from DigiKey, Mouser, and LCSC, cross-references pin-compatible drop-in alternatives, and adds practical thermal and layout guidance not present in the stock datasheet summary.
Drop-in alternatives for AOZ2261NQI-11 — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
AOZ2261NQI
✅ Drop-In📋 Reference alternative (not in catalog)
AOZ2261AQI-15
✅ Drop-In📋 Reference alternative (not in catalog)
AOZ2261NQI-12
✅ Drop-In📋 Reference alternative (not in catalog)
AOZ2261BQI-11
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
AOZ2261NQI-10
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
AOZ2261CQI-11
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
AOZ2261NQI-11 Maximum Ratings & Electrical Characteristics
| Topology | Synchronous Buck (Step-Down) |
| Input Voltage Range | Up to 28 V |
| Continuous Output Current | 8 A |
| Output Voltage Range | 0.6 V to 23.8 V (adjustable, +/-1%) |
| Reference Voltage Accuracy | +/-1% |
| Programmable On-Time | 100 ns to 2.6 microseconds |
| Switching Control | Constant On-Time (COT) |
| Internal MOSFETs | High-side and low-side N-channel (integrated) |
| Package | QFN-23L (4 mm x 4 mm, PowerTFQFN with exposed pad) |
| Operating Temperature Range | -40C to +85C (ambient) |
| Protection Features | VCC UVLO, cycle-by-cycle current limit, output OVP, short-circuit protection, thermal shutdown |
| Mounting Type | Surface Mount |
| RoHS Status | Compliant |
| Marking Code | ALNB |
| Output Type | Adjustable (Positive) |
| Number of Outputs | 1 |
AOZ2261NQI-11 Pin Configuration
| Pin 1 | PGND — Power ground return for low-side FET |
| Pin 2 | LX — Switching node, connect to output inductor |
| Pin 3 | LX — Switching node, connect to output inductor |
| Pin 4 | PGND — Power ground return for low-side FET |
| Pin 5 | VIN — Main input supply voltage |
| Pin 6 | VIN — Main input supply voltage |
| Pin 7 | BST — Bootstrap capacitor node for high-side gate drive |
| Pin 8 | NC — Not connected |
| Pin 9 | EN — Enable input, active high |
| Pin 10 | VCC — Internal 5V LDO output for gate drive |
| Pin 11 | PGOOD — Power good open-drain output |
| Pin 12 | AGND — Analog ground, connect to PGND at single point |
| Pin 13 | FB — Feedback voltage input from output divider |
| Pin 14 | COMP — Compensation node for constant on-time loop |
| Pin 15 | TON — On-time programming resistor input |
| Pin 16 | SS — Soft-start capacitor node |
| Pin 17 | NC — Not connected |
| Pin 18 | NC — Not connected |
| Pin 19 | NC — Not connected |
| Pin 20 | PGND — Power ground return |
| Pin 21 | PGND — Power ground return |
| Pin 22 | PGND — Power ground return |
| Pin 23 | PGND — Power ground return |
Typical Applications
AOZ2261NQI-11 is suitable for 7 applications: Notebook Computer Core and Chipset Rails, 12V Distributed Bus Point-of-Load Converters, Networking and Telecom POL Supplies, FPGA and SoC Core Rails, Industrial 24V Bus Power Conversion, Solid-State Drive and Storage Power, Automotive Infotainment and ADAS Power.
Notebook Computer Core and Chipset Rails
The AOZ2261NQI-11 fits notebook core and chipset rails because its 8A continuous output, 0.6V minimum VOUT, and 28V input cover the full range from 19V adapter input to modern sub-1V SoC cores. With 90%+ efficiency from constant on-time control and integrated high-side/low-side FETs in a 4mm x 4mm QFN, it removes the external MOSFETs and Schottky diode that bulk up discrete buck designs. Designers save roughly 60 percent PCB area compared to a controller-plus-discrete-FET solution at the same 8A load, and the 100ns-2.6us programmable on-time lets them push switching frequency above 1 MHz to shrink the output inductor below 1 uH.
Recommended
12V Distributed Bus Point-of-Load Converters
On 12V distributed power rails, the AOZ2261NQI-11 converts system bus voltage down to 0.6V-5V for downstream ASICs, FPGAs, and DDR memory with one converter per load zone. Its 28V absolute maximum tolerates transients and load-dump events common on industrial 12V buses, while the integrated synchronous FETs and constant on-time control deliver fast transient response without external compensation. At 12V to 1.8V at 8A, typical efficiency lands near 92 percent, reducing heatsinking versus a linear regulator that would dissipate approximately 80W at the same load. The 4mm x 4mm QFN footprint fits directly under the BGA of dense POL arrays.
Recommended
Networking and Telecom POL Supplies
Networking switches, routers, and telecom line cards use 28V or 12V intermediate bus architectures where the AOZ2261NQI-11 acts as the final point-of-load step-down to 1V-3.3V for processors and SerDes PHYs. Its 0.6V minimum output supports modern ASIC core voltages, while integrated OVP, SCP, UVLO, and thermal shutdown provide the fault tolerance required in always-on telecom equipment. The constant on-time architecture reacts within one switching cycle to load steps, critical when a SerDes PHY suddenly demands bursts of current for line-rate packet processing. The exposed thermal pad handles the full 8A continuous load at 70C ambient when laid out on 1 square inch of copper.
Recommended
FPGA and SoC Core Rails
FPGAs and high-performance SoCs require multiple low-voltage rails often below 1V at currents up to 8A. The AOZ2261NQI-11 covers 0.6V-1.2V core rails, while the 0.6V minimum enables direct powering of the lowest-voltage processor cores without a stacked second stage. Constant on-time control responds within microseconds to load steps when the FPGA transitions between idle and full fabric utilization, avoiding the droop that triggers brown-out resets. The 4mm x 4mm footprint mounts directly under the BGA on the bottom side of the PCB, freeing the top side for signal routing and decoupling capacitors near the load pins.
Recommended
Industrial 24V Bus Power Conversion
Industrial automation, motor control, and PLC systems often run on a 24V nominal bus with transients above 30V. The AOZ2261NQI-11's 28V absolute maximum and 8A continuous output let it step the 24V bus down to 5V, 3.3V, or 1.8V for digital logic, sensor interfaces, and communication PHYs. Its wide VOUT range from 0.6V to 23.8V means the same part covers both high-current 24V-to-5V conversion and low-voltage 5V-to-1V downstream conversion, reducing the BOM diversity in an industrial product family. Integrated protection features (UVLO, OVP, SCP, OCP, OTP) satisfy the fault-tolerance requirements of IEC 61131-2 industrial control equipment.
Recommended
Solid-State Drive and Storage Power
Enterprise SSDs and NVMe storage devices need compact, high-efficiency 12V-to-1.2V or 5V-to-0.8V conversion for NAND and controller ICs. The AOZ2261NQI-11's 8A output supports multi-NAND-pack designs at 0.8V-1.2V, while its 4mm x 4mm QFN fits inside the thermally constrained M.2 or U.2 form factor. With constant on-time control the part avoids the subharmonic instability that plagues voltage-mode controllers at high step-down ratios above 10:1, common in 12V-to-1V storage power trees. Integrated thermal shutdown plus exposed-pad cooling handles the sustained 6-8A load of read/write bursts without throttling.
Recommended
Automotive Infotainment and ADAS Power
Automotive infotainment head units and ADAS domain controllers operate from 12V battery rails with load-dump transients up to 35V. While the AOZ2261NQI-11's 28V absolute maximum does not cover the full automotive load-dump profile without external TVS protection, it fits comfortably in cabin-electronics subsystems where transients are clamped below 28V. The 8A output powers multiple SoCs, DDR rails, and display controllers from a single converter, and the small QFN-23L footprint integrates into space-constrained head-unit PCBs. Designers should add external automotive-qualified TVS and input fusing for full ISO 7637-2 compliance.
Recommended
Recommended Products Summary
Engineering reference data for AOZ2261NQI-11 — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | AOZ2261NQI | AOZ2261AQI-15 | AOZ2261NQI-10 |
|---|---|---|---|---|
| Brand | Alpha & Omega Semiconductor | Alpha & Omega Semiconductor | Alpha & Omega Semiconductor | Alpha & Omega Semiconductor |
| Package | QFN-23L (4x4 mm) | QFN-23L (4x4 mm) - same | QFN-23L (4x4 mm) - same | QFN-23L (4x4 mm) - same |
| Input Voltage (max) | 28 V | 28 V | 28 V | 28 V |
| Output Current (continuous) | 8 A | 8 A | 8 A | 8 A |
| Output Voltage Range | 0.6 V to 23.8 V | 0.6 V to 23.8 V | 0.8 V to 23.8 V | 0.6 V to 23.8 V |
| On-Time Range | 100 ns to 2.6 microseconds | 100 ns to 2.6 microseconds | 100 ns to 2.6 microseconds | 100 ns to 2.6 microseconds |
| Control Topology | Constant On-Time (COT) | Constant On-Time (COT) | Constant On-Time (COT) | Constant On-Time (COT) |
| Integrated FETs | Yes (high-side + low-side) | Yes (high-side + low-side) | Yes (high-side + low-side) | Yes (high-side + low-side) |
| Reference Voltage Accuracy | +/-1% | +/-1% | +/-1% | +/-1% |
Key Differentiators
- Lowest VOUT in AOS 8A EZBuck family (vs AOZ2261AQI-15)
- Drop-in backward compatibility with predecessor (vs AOZ2261NQI)
- Higher switching frequency capability than older AOS bucks (vs AOZ2261NQI-10)
Design Notes
Estimated: at VIN=12V, VOUT=3.3V, and 8A continuous load, the AOZ2261NQI-11 dissipates approximately (12V - 3.3V) x 8A x (1 - efficiency)/efficiency. Assuming 92 percent efficiency, that is roughly 6W. Without a generous copper pour on the exposed thermal pad (at least 1 square inch of 2 oz copper), the junction temperature will exceed 125C and trigger thermal shutdown. For full 8A continuous operation at 12V input, place thermal vias under the exposed pad on a 1.0mm pitch and connect them to an internal copper plane on the bottom layer.
Place the input ceramic bypass capacitors (typically 22 microfarad X5R or better, 25V or higher rating) within 2mm of the VIN and PGND pins to suppress switching-node ringing. Keep the BST capacitor trace short (under 5mm) and route the LX node away from FB and AGND to avoid noise coupling. The output inductor should be placed within 3mm of LX, and the output ceramic capacitors (typically 2 x 22 microfarad X5R) should sit at the inductor pad to minimize the high-frequency loop area.
Do not exceed the 28V absolute maximum VIN rating; add a TVS diode or input fuse on 24V industrial buses that can see transients above 28V. The TON programming resistor sets the on-time and therefore the switching frequency - choosing too small a value pushes switching frequency above 1 MHz and reduces efficiency; too large a value risks subharmonic instability. Always populate the SS capacitor to control inrush current during startup; leaving SS floating disables soft-start and can trigger OVP during heavy load transients.
The FB trace must be routed away from the LX switching node and the BST trace to avoid injected ripple that causes output voltage jitter. Use a Kelvin connection to the output capacitors at the load point for the feedback divider, and keep the FB trace short (under 10mm) and surrounded by AGND copper. For output voltages below 1V, use a low-offset precision resistor divider (1 percent or better) on FB to maintain regulation accuracy within the +/-1 percent reference tolerance.
Compliance Information
RoHS compliant per AOS product page. AEC-Q100 not qualified - not recommended for automotive safety-critical applications. Halogen-free status not explicitly stated in provided data.
