Maxim Debuts Single Input Multiple Output (SIMO) Power Management IC (PMIC)
The unit offers a 300mA battery charger, three independent power rails, and a separate LDO output.
The MAX77659 from Maxim Integrated (now part of Analog Devices) offers two inputs, battery, and charger. The unit integrates a switched-mode, buck-boost regulator that provides the battery charging rail and also three outputs that are separately programmable over a range of 0.5 to 5.5V. An internal LDO also provides a low ripple output of up to 100mA, useful for noise-sensitive applications such as audio.
Simplified block diagram for the MAX77659. Image courtesy of Maxim.
By utilizing just one inductor to power three different voltage rails, the MAX77659 frees up the board space that separate inductors would otherwise take up. The level of integration serves to lower BOM count, freeing up still more precious board space. The unit operates at 91% efficiency when powering moderate or heavy loads, and when powering only light loads, the PMIC draws only 5µA. The Shutdown current is 0.3µA.
The Utility of SIMO Technology When Saving Space is Essential
As noted by Roger Yeung, Executive Business Manager for the Battery Power Solutions Business Unit at Maxim Integrated, now part of Analog Devices, “Analog Devices’ SIMO product technology shrinks size and boosts performance in the smallest of hearable and wearable devices.” He goes on to state that, “The MAX77659 brings the ‘on-the-go’ lifestyle to the next level by minimizing plug-in time and maximizing play time. The MAX77659 PMIC frees up board real estate to pack in additional features such as expanded memory storage, location tracking, and vital sensing demanded by today’s portable consumer and medical devices.”
The MAX77659 is Optimized for Small Sized Batteries
The PMIC can charge an array of lithium-ion batteries with a range of charge current specifications and termination voltage options. At the same time, it also minimizes heat generation even during fast charging.
The input operating voltage can be from 3.4V to 5.5V, and the fast charge current is programmable from 7.5mA to 300mA. Battery regulation voltage and termination current are also both programmable, from 3.6V to 4.6V and from 0.375mA to 45mA, respectively. The MAX77659 also features thermal regulation and Japan Electronics and Information Technology (JEITA) compliance.
The three power rails, SBB0, SBB1, and SBB2, can deliver up to 500mA in total. Conditions are outlined in the datasheet.
Flexibility and Configurability
The PMIC features two GPIO pins and a bidirectional I2C interface to establish the unit’s configuration and for status checking. The device also has one-time programmable (OTP) features that are set by the manufacturer.
- Bluetooth headphones and hearables
- True wireless stereo (TWS) earbuds
- Medical wearables
- Hearing aids
- The MAX77659 is available in a 6 x 5, 30-bump, 0.4mm pitch wafer level package (WLP). Dimensions are 2.55mm x 2.37mm.
- Operating temperature range is from -40°C to +85°C.
- Versions are RoHS compatible
Getting to Market Faster
Maxim offers the MAX77659 evaluation kit to allow designers to explore the MAX77659’s extensive range of features and capabilities. The kit’s software runs on Microsoft Windows and provides an easy-to-use graphical interface, and also a register-based interface, to exercise the many features of the PMIC.