Product Descriptions

The RK818 is a complex power-management integrated circuit (PMIC) for multi-core system applications powered by a Li-ion or a Li-ion polymer battery cell, or by a 5V input either from an USB port or from an adaptor. The RK818 can provide a complete power management solution with very few external components.

The RK818 provides four configurable synchronous step-down converters and one synchronous step-up converter with current capability up to 4A and 2.5A, respectively. The device also contains 9 LDO regulators, one linear switch, one switch-mode charger, a battery fuel gauge, and the power path management function. Power-up/power-down controller is configurable and can support any customized power-up/power-down sequences (OTP based). A real-time clock (RTC) is also integrated to provide a 32-kHz output buffer, and real time function. The RK818 supports 32-kHz clock generation based on a crystal oscillator. 

The switch-mode charger, together with the power path controller integrated in the RK818, allows supplying power to the loads while it is charging the battery. The charger provides functions such as input current limiting, trickle current charging, constant current (CC)/constant voltage (CV) charging, charging termination, charging over time protection, etc. All these functions can be conveniently configured through the I2C digital interface. The input current limit can be set to maximum 3A to accommodate a power adaptor as the input supply. When an input current limiting is triggered, the power path controller will distribute the input power in a way that the loads have the higher priority than the battery to take the input power. The difference between the input and output power will be used to charge the battery. In a case that the output power required by the loads exceeds the input power, the power path controller will automatically turn on the battery switch so that the battery can supply extra power to the loads together with the input supply. A “battery fuel gauge” is also integrated in the RK818. Using the proprietary algorithms and the sensed battery current and voltage, the gauge can accurately calculate the battery capacity based on the charging/discharging characteristics of the battery preloaded in the system. The gauge then sends the battery capacity information to the processor through the I2C interface. Other functions that the charger provides includes tiny current charging for an over discharged battery, or so called “dead battery”, battery temperature monitoring, safe charging timer and over temperature shut down.

The RK818 can dynamically adjust the output voltage of each DC-DC converter, as required by the processor based on the processor’s operation status so as to maximize the system efficiency. The output voltages of most channels can be configured through the I2C interface. The inputs of all channels have soft start function, which greatly reduces the inrush current at the startup. The frequency compensations of all the control loops are implemented internally to eliminate external compensation components. 

The 2MHz switching frequency allows small size inductors to be used for both buck and boost converters. Also, as all the power switches are integrated on chip, no external power switches and Schottky diodes are needed, which reduces the system cost significantly.

The RK818 is available in a QFN68 7.0 mm x 7.0 mm package, with a 0.35-mm pin pitch.

Product Features

 Input range: 3.8V - 6V for USB input； 2.7V - 4.5V for BAT input 

 Switch mode Li-ion battery charger providing charging current up to 3A.  

 Power path controller with 5A current path. 

 Accurate battery fuel gauge. 

 Real time clock（RTC） 

 Low standby current of less than 40uA (at 32KHz clock frequency) 

 2MHz switching frequency for the buck converters  

 1MHz switching frequency for the boost converter 

 Fast transient response due to the current mode architecture 

 Internal frequency compensation and soft start  

 Programmable output voltage and power up/down sequence through I2C interface 

 Proprietary circuit architecture achieving high efficiency 

 Internal discharge path in off state for BUCs and LDOs 

 Power channels:

 Ch1: Synchronous buck converter, 4A max 

 Ch2: Synchronous buck converter, 4A max 

 Ch3: Synchronous buck converter, 2.5A max 

 Ch4: Synchronous buck converter, 2.5A max 

 Ch5: Synchronous boost converter, 2.5A max 

 Ch6－7, Ch9 and Ch11: LDOs, 150mA max 

 Ch8: Low noise, high PSRR LDO ,100mA max 

 Ch10, 12,14: LDOs, 300mA max 

 Ch13: LDO, 400mA max

 Ch15: Low Rdson switch,0.15ohm（Vgs=3V） 

 Ch16: HDMI5V switch， 80mA max 

 Ch17：OTG switch，800mA max 

 Fixed and programmable power up/down sequences 

 Package: 7mmx7mm QFN68

Actual product photos

Product Data Manual：

For more product information, please download the PDF

Payment&Transportation

Official Certificate&Certificate

Multiple product supply

Company office environment

Warehouse Real Shot

Standard packaging

We also provide ：