Item specifics
Description
RK816B-3 Product Overview
The RK816B-3 is a complex Power Management Integrated Circuit (PMIC) from Rockchip, packaged in QFN-40 (5×5×0.8mm, 0.4mm pitch). Designed for multi-core systems powered by lithium-ion polymer batteries or 5V input from USB ports/power adapters, the device integrates 4 high-efficiency synchronous step-down DCDC converters, 6 LDO linear regulators, and complete battery charging management.
The PMIC supports USB input (3.8V to 5.5V) and battery input (2.7V to 4.5V) with terminal battery voltage up to 4.35V, featuring OTG output capability up to 850mA. Operating temperature range is -40°C to 125°C for industrial applications. The RK816B-3 is primarily paired with Rockchip RK3308 and PX3-SE application processors.
RK816B-3 Core Features
DCDC Converters： 4 synchronous buck converters. BUCK1/BUCK2: 2.7V-5.5V input, 0.7125V-2.3V output, 2A max. BUCK3/BUCK4: 2.7V-5.5V input, up to 1A output
LDO Linear Regulators： 6 LDOs with 2.7V-5.5V input, 0.8V-3.4V output. LDO3: low-noise high-PSRR, 100mA max. Others: 300mA max
Battery Charging Management： Integrated charger for lithium-ion polymer batteries. USB input 3.8V-5.5V, battery input 2.7V-4.5V, terminal voltage up to 4.35V
OTG Function： Integrated OTG output up to 850mA for USB On-The-Go capability
Power Sequencing： Programmable power-up/down sequencing with Dynamic Voltage Scaling (DVS) support
Protection Features： Built-in overcurrent and overtemperature protection
Package Type： QFN-40 (5×5×0.8mm) with 0.4mm pitch, exposed pad
Temperature Range： Industrial grade -40°C to 125°C
Environmental Compliance： Lead free, RoHS compliant
RK816B-3 Applications
Smart Audio Devices： Paired with RK3308 for smart speakers, voice assistants, audio players
Embedded Systems： Paired with PX3-SE for industrial motherboards, HMIs, IoT gateways
Portable Devices： Handheld devices, portable media players, e-readers
Industrial Control： Industrial automation equipment, PLC controllers, field instruments
IoT Devices： Smart home gateways, sensor nodes, edge computing devices
RK816B-3 Key Advantages
High Integration Power+Charger 2-in-1： Single RK816B-3 integrates 4 DCDCs, 6 LDOs, and battery charger with total 10 power channels, saving PCB area and BOM cost
Complete Charging Management： Supports USB and battery inputs with terminal voltage up to 4.35V. Built-in charging eliminates external charger ICs
Industrial Grade Wide Temperature： -40°C to 125°C operating range for industrial equipment, outdoor devices, and 24/7 IoT products
Flexible Power Configuration： 4 DCDCs from 0.7125V to 3.5V with 2A/1A options. 6 LDOs with low-noise high-PSRR option for sensitive analog circuits
Integrated OTG Functionality： 850mA OTG output for reverse charging of smartphones and peripherals
Proven Embedded Application Support： Qualified for RK3308 and PX3-SE processors with complete reference designs and mature application cases in smart speakers and industrial embedded systems
Mature Ecosystem： Rockchip provides complete reference designs, datasheets, and application guides with rich development resources and comprehensive technical support
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FAQ:
What is the RK816B-3 PMIC and its key specifications?
The RK816B-3 is a highly integrated Power Management IC (PMIC) from Rockchip, designed to supply and manage power for portable and embedded devices. It combines 4 DC‑DC synchronous buck converters, 6 LDOs, a complete single‑cell Li‑Ion battery charger, a fuel gauge, and an RTC. The device communicates via I2C (default address 0x1A) and is housed in a compact QFN‑40 package (5 mm × 5 mm). Key input voltage range: 2.7 V – 5.5 V. It is a cost‑optimized, all‑in‑one power solution primarily targeted at Rockchip SoCs that do not require an integrated audio codec.
How many DC‑DC buck channels and LDOs does the RK816B-3 have, and what are their output capabilities?
The RK816B-3 integrates four synchronous buck converters: BUCK1 and BUCK2 can each deliver up to 2.5 A, BUCK3 up to 1.5 A, and BUCK4 up to 2 A. It also includes six LDO channels, each typically capable of supplying 200 mA – 300 mA. All output voltages are programmable via I2C, allowing the host processor to adjust core, I/O, and peripheral voltages dynamically for power‑saving modes (DVFS).
Does the RK816B-3 support battery charging? What are the charging specifications?
Yes, it includes a switching battery charger designed for single‑cell Li‑Ion/Li‑Poly batteries. The charging current can be programmed up to 2 A, with a dedicated charger input voltage of 4.5 V – 5.5 V. It supports constant‑current/constant‑voltage (CC/CV) charging, battery temperature monitoring, and automatic power‑path management to power the system while charging. A built‑in fuel gauge estimates battery capacity using voltage‑based algorithms.
How does the RK816B-3 differ from the RK817-5 PMIC?
While both are Rockchip PMICs with similar DCDC/LDO and charging capabilities, the main difference is that the RK817-5 includes an integrated audio codec (DAC, headphone amp, microphone input), whereas the RK816B-3 does not have any audio functions. The RK816B-3 also comes in a smaller QFN‑40 (5×5 mm) package compared to the RK817-5’s QFN‑68 (7×7 mm), making it a more compact and cost‑effective choice for applications that do not need on‑chip audio. Both support I2C control and battery charging.
How do I control the RK816B-3, and what is its I2C address?
All functions are controlled through a standard I2C serial interface. The default 7‑bit I2C address is 0x1A (write). The host SoC can read and write internal registers to set output voltages, enable or disable power channels, adjust charging parameters, and read status flags. The I2C interface operates at up to 400 kHz.
What protection features does the RK816B-3 include?
The RK816B-3 provides comprehensive safeguards: cycle‑by‑cycle over‑current protection (OCP) on each DCDC and LDO, over‑temperature protection (OTP) with hysteresis, under‑voltage lockout (UVLO) on the main input, battery over‑voltage / over‑discharge protection, and a thermal shutdown mechanism. These features help ensure safe operation under fault conditions and prolong battery life.
What is the input voltage range, and what power sources can be used?
The main system input voltage range is 2.7 V to 5.5 V, allowing the PMIC to be powered directly from a USB port (5 V), a single‑cell Li‑Ion battery (3.0 V – 4.2 V), or a regulated 3.3 V / 5 V supply. The separate charger input accepts 4.5 V – 5.5 V, typically connected to a USB or adapter input. This flexibility supports both battery‑only and always‑powered applications.
How small is the QFN‑40 package, and what are the PCB design implications?
The RK816B-3 comes in a QFN‑40 package measuring only 5 mm × 5 mm with a lead pitch of 0.4 mm. It features an exposed thermal pad on the bottom for efficient heat dissipation. The tiny footprint, combined with high integration, significantly reduces the overall PCB area required for the power management subsystem, making it ideal for space‑constrained designs such as IoT modules, portable media devices, and compact embedded systems.
What are the most typical applications for the RK816B-3?
This PMIC is widely used in portable IoT devices, smart sensors, tablets and e‑readers (without audio requirements), industrial handhelds, and other battery‑powered products that use Rockchip SoCs such as RK3128, RK3288, PX30, RK3326, and similar. Its compact size, integrated charger, and I2C programmability make it a one‑chip solution for many cost‑sensitive, space‑limited designs.
How does the RK816B-3 compare to the RK818 or RK805 PMICs?
Compared to the older RK818 (which also includes audio and a larger package), the RK816B-3 offers a simpler, more compact solution for designs where audio is handled elsewhere or not needed. The RK805 is a smaller PMIC with fewer DCDC channels and no charger; the RK816B-3 provides higher integration with battery management in a still‑small footprint. Therefore, the RK816B-3 is the preferred choice for a balanced, cost‑effective power solution with charging capability for mainstream Rockchip platforms.