AXP323 Power Management IC PMIC 3xDCDC+3xLDO QFN-20-EP (3×3mm)

AXP323 Product Overview

The AXP323 is a highly integrated Power Management IC (PMIC) from X-Powers, distributed and supported by Allwinner, in QFN-20-EP (3×3mm) ultra-compact package. The chip integrates 3 high-performance DCDC buck converters and 3 LDO linear regulators, supporting TWSI (Two Wire Serial Interface) communication with configurable slave address of 0x36 or 0x37. The AXP323 is an enhanced version of the AXP313A, with the key difference being that DCDC1 and DCDC2 support dual-phase operation, increasing maximum output current to 5A. The chip is widely used in OTT boxes, IP cameras, smart speakers, and Allwinner A523 platforms for low-power applications. It can be used standalone or combined with other PMICs like the AXP717 for multi-rail power solutions.

AXP323 Core Features

3-Channel High-Performance DCDC Converters： DCDC1 supports 0.5~1.2V (10mV/step), 1.22~1.54V (20mV/step), 1.6~3.4V (0.1V/step), IMAX=3A@VIN=5V. DCDC2 supports 0.5~1.2V (10mV/step), 1.22~1.54V (20mV/step), IMAX=3A@VIN=5V. DCDC3 supports 0.5~1.2V (10mV/step), 1.22~1.84V (20mV/step), IMAX=3A@VIN=5V. All DCDCs use COT architecture with efficiency up to 82%@5V-0.9V-1A

Dual-Phase Operation Mode： DCDC1 and DCDC2 support dual-phase operation. When combined, the maximum output current reaches 5A, providing ample power delivery for high-performance application processors. This is the key difference between AXP323 and AXP313A

3-Channel LDO Regulators： RTCLDO supports 1.8/2.5/2.8/3.3V, IMAX=30mA; ALDO1 supports 0.5~3.5V (0.1V/step), IMAX=300mA with peak >600mA; DLDO1 supports 0.5~3.5V (0.1V/step), IMAX=500mA with peak >900mA

TWSI Communication Interface： Supports TWSI (Two Wire Serial Interface) communication mode with configurable slave address of 0x36 or 0x37 (7 bits), enabling the host processor to manage power and monitor status

Sequencing and Customization： Power-up sequencing and default voltages for DCDC/LDO are customizable, meeting the strict timing requirements of various application processors

Comprehensive Protection Features： Integrated internal temperature sensor with overtemperature protection, DCDC undervoltage/overvoltage protection (OVP/UVP), and overcurrent protection (OCP) ensure safe and stable power system operation

Ultra-Compact Package： QFN-20-EP (3×3mm) package with exposed pad for thermal dissipation, ideal for space-constrained compact PCB designs

Allwinner A523 Platform Companion： The AXP323 is designed as the companion power solution for Allwinner's next-generation processors like A523, with mainline Linux and U-Boot support

AXP323 Applications

Allwinner A523 Platform Companion Power： Complete power management solution for Allwinner A523 processors, with official mainline Linux kernel and U-Boot support

OTT Boxes and TV Boxes： Main power management IC for home entertainment devices such as network media players and smart TV boxes

IP Cameras： Core power management chip for network cameras in security surveillance applications

Smart Speakers： Core PMIC for smart speaker products, providing multiple power rails for processors, audio amplifiers, and wireless modules

Embedded Boards： Power management for industrial embedded boards, development boards, and other applications requiring multiple power outputs

Battery-Powered Portable Devices： Can be combined with a BMU (Battery Management Unit) for complete battery application power solutions

AXP323 Key Advantages

5A Output via Dual-Phase Mode： The key differentiator between AXP323 and AXP313A is dual-phase operation support for DCDC1 and DCDC2. When combined, maximum output current reaches 5A, providing ample power margin for high-performance application processors, especially suitable for higher-frequency processor platforms

High Integration Design： Single chip integrates 3 DCDCs and 3 LDOs, totaling 6 power rails. Combined with QFN-20-EP ultra-small package, this significantly saves PCB area and reduces external component count, lowering BOM cost and design complexity

Flexible Programmable Configuration： TWSI bus enables dynamic configuration of output voltages. DCDC/LDO sequencing and default voltages are customizable, allowing the same hardware platform to adapt to different processors and system requirements

Comprehensive Protection Mechanisms： Integrated overvoltage protection (OVP), undervoltage protection (UVP), overcurrent protection (OCP), and overtemperature protection (OTP) prevent system damage under abnormal conditions

Excellent Power Conversion Efficiency： DCDC converters use COT architecture with efficiency up to 82%@5V-0.9V-1A, reducing energy loss and heat generation, particularly suitable for thermally constrained compact products

Complete Mainline Linux/U-Boot Support： AXP323 has official support in mainline Linux kernel and U-Boot, sharing driver code with AXP313A, resulting in very low software adaptation cost

Seamless Allwinner SoC Integration： Forms a complete Turnkey solution with Allwinner's next-generation processors like A523, with reference designs and driver support from the original manufacturer

Reliable Supply Chain： Genuine Allwinner/X-Powers product with stable supply, transparent pricing, and clear cost advantages for volume purchasing

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FAQ:

1. What is the AXP323 PMIC and its key specifications?
   The AXP323 is a highly integrated Power Management Integrated Circuit (PMIC) from X‑Powers, designed for low‑power embedded applications. It integrates 3 synchronous step‑down DC‑DC converters (bucks) and 3 low‑dropout regulators (LDOs). Key features: input voltage range 2.7 V – 5.5 V, I2C control (default address 0x34), and a tiny QFN‑20‑EP package (only 3 mm × 3 mm). It does not include a battery charger, making it ideal for mains‑powered or battery‑free designs that require only efficient voltage regulation and power sequencing.

2. What are the output capabilities of the three DC‑DC buck converters?
   The three buck converters provide the main power rails: DCDC1 is typically fixed at 3.3 V (optionally 3.0 V or 2.5 V) and can source up to 1.2 A. DCDC2 is adjustable from 1.0 V to 1.5 V (often set to 1.2 V or 1.35 V for CPU core) and also delivers up to 1.2 A. DCDC3 provides a selectable output such as 3.3 V or 1.8 V with up to 1.2 A. All outputs are enabled and set via I2C registers.

3. What are the LDO outputs and their current ratings?
   The three LDOs supply low‑noise, low‑power rails: LDO1 is typically configured for 2.5 V or 3.0 V (analog supply) at up to 200 mA. LDO2 provides 1.8 V (often for digital I/O or PLL) with up to 200 mA. LDO3 is the always‑on RTC supply, outputting 1.8 V or 1.2 V with a very low quiescent current (suitable for backup domain). These LDOs are ideal for powering external sensors, audio codecs, and other sensitive analog circuits.

4. How do I control the AXP323, and what is its I2C address?
   All voltage settings, power‑on sequencing, and status monitoring are done through a standard I2C serial interface (up to 400 kHz). The default 7‑bit I2C address is 0x34 (write). By reading and writing internal registers, the host SoC can dynamically set output voltages, enable or disable individual power channels, read power‑good status, and handle interrupt events. This level of control enables efficient power management and dynamic voltage scaling in embedded systems.

5. What protection features does the AXP323 include?
   The AXP323 provides comprehensive hardware protections: over‑current protection (OCP) per channel, over‑temperature protection (OTP) with hysteresis, under‑voltage lockout (UVLO) on the input, and soft‑start on all power outputs to limit inrush current. It also includes a power‑good (PG) indicator and an interrupt output to notify the host of fault conditions, ensuring safe operation in industrial and consumer devices.

6. What is the typical input voltage range, and what supplies can power the AXP323?
   The PMIC accepts a wide input voltage from 2.7 V to 5.5 V. This means it can be powered directly from a 5 V USB rail, a single‑cell Li‑Ion battery (3.0 V – 4.2 V) (when a separate charger is used), or a standard 3.3 V or 5 V regulated supply. The wide range gives designers flexibility for battery‑backed and mains‑powered applications without additional converters.

7. How does the AXP323 differ from the AXP209 or AXP228 PMICs?
   The AXP209 and AXP228 are higher‑end PMICs that include an integrated Li‑Ion battery charger and a larger number of DCDC/LDO channels. The AXP323 is a more streamlined, cost‑effective solution that does not have a charger and provides only 3 DCDC + 3 LDO channels. It is designed for systems that either do not need a battery (mains‑powered) or use an external charger IC. This makes the AXP323 smaller (QFN‑20‑EP, 3×3 mm) and more efficient for simple power‑regulation tasks.

8. What Allwinner SoCs and platforms typically use the AXP323?
   The AXP323 is commonly paired with entry‑level and cost‑sensitive Allwinner processors, such as the Allwinner A33, R16, V3s, V3, and S3. These SoCs often appear in tablets, IoT devices, smart speakers, and industrial control panels that require a compact, reliable PMIC without battery charging. The AXP323 is designed to work seamlessly with these chips, providing the required core, memory, and I/O voltages under software control.

9. What are the package dimensions and PCB design considerations?
   The AXP323 uses a very small QFN‑20‑EP package measuring only 3 mm × 3 mm, with a lead pitch of 0.4 mm. The exposed thermal pad on the bottom must be soldered to a ground plane for heat dissipation. Thanks to the high switching frequency of the DCDC converters (typically 2.25 MHz), small external inductors and capacitors can be used, making the total solution footprint extremely compact — ideal for space‑constrained designs such as wearables, camera modules, and compact IoT nodes.

10. Can the AXP323 be used in battery‑powered devices?
    Yes, but only if an external battery charger is added. The AXP323 itself does not charge a battery, but it can be powered from a single‑cell Li‑Ion battery (3.0 V – 4.2 V) and regulate the system voltages. The built‑in LDO3 is designed as an always‑on RTC supply, drawing extremely low quiescent current to keep time and critical registers alive during power‑down. For applications requiring a complete power and charging solution, the AXP209 or AXP228 would be more suitable.