Processor Power Management Subsystem

The WM8325 is an integrated power-management subsystem which provides a cost-effective, flexible, single-chip solution for power management. It is specifically targeted at the requirements of a range of low-power portable consumer products, but is suitable to any application with a multimedia processor. The WM8325 is designed to operate as a system PMIC supporting the ARM9™, ARM11™ and ARM Cortex-A™ processors, but is also capable of supporting the majority of application and mobile processors at the heart of a wide range of low-power consumer multimedia applications. The start-up behaviour and configuration is fully programmable in an integrated OTP non-volatile memory. This highly flexible solution helps reduce time-to-market, as changing application requirements can be very easily accommodated in the OTP. The InstantConfig™ interface enables an external EEPROM to configure the WM8325. The WM8325 power management subsystem comprises four programmable DC-DC converters and eleven LDO regulators (four of which are low-noise for supplying sensitive analogue subsystems). The integrated OTP bootstrap circuitry controls the start-up sequencing and voltages of the converters and regulators as well as the sequencing of system clocks. The DC-DC converters deliver high performance and high efficiency across a wide range of operating conditions. They are optimised to support the high load current transients seen in modern processor core domains. DC-DC3 / DC-DC4 can be connected together and operated in ‘dual’ mode to support an increased current load of up to 1.6A. An on-chip regulator provides power for always-on PMIC functions such as register map and the RTC. The device provides autonomous backup battery switchover. A low-power LDO is included to support ‘Alive’ processor power domains external to the WM8325. A 12-bit Auxiliary ADC supports a wide range of applications for internal as well as external analogue sampling, such as voltage detection and temperature measurement. WM8325 includes a crystal oscillator and an internal RC oscillator to generate all clock signals for autonomous system start-up and processor clocking. A Secure Real-time Clock (SRTC) and alarm function is included, capable of waking up the system from low-power modes. A watchdog function is provided to ensure system integrity. To maximise battery life, highly-granular power management enables each function in the WM8325 subsystem to be independently powered down through a control interface or alternatively through register and OTP-configurable GPIOs. The device offers a standby power consumption of <7µA, making it particularly suitable for portable applications. The WM8325 is supplied in an 8x8mm 81-lead QFN package, ideal for use in portable systems. The WM8325 forms part of the Cirrus Logic series of audio and power management solutions, and is widely register compatible with the WM831X devices.

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Power Management


Power Management
  • 1 x DC-DC synchronous buck converter (0.6V - 1.8V, 2.5A, DVS)
  • 1 x DC-DC synchronous buck converter (0.6V - 1.8V, 1.25A, DVS)
  • 2 x DC-DC synchronous buck converters (0.85V - 3.4V, 1A)
  • 1 x LDO regulator (0.9V - 3.3V, 300mA, 1Ω)
  • 2 x LDO regulators (0.9V - 3.3V, 200mA, 1Ω)
  • 3 x LDO regulators (0.9V - 3.3V, 100mA, 2Ω)
  • 2 x Low-noise LDO regulators (1.0V - 3.5V, 200mA, 1Ω)
  • 2 x Low-noise LDO regulators (1.0V - 3.5V, 150mA, 2Ω)
  • 1 x ‘Alive’ regulator (0.8V – 1.55V, up to 25mA)
System Control
  • I²C or SPI compatible primary control interface
  • Comprehensive interrupt scheme
  • Watchdog timer and system reset control
  • Autonomous power sequencing and fault detection
  • OTP memory bootstrap configuration function
Additional Features
  • Auxiliary ADC for multi-function analog measurement
  • 128-bit pseudo-random unique ID
  • Secure Real-Time Clock with wake-up alarm
  • 12 x configurable multi-function (GPIO) pins
  • Comprehensive clocking scheme: low-power 32kHz RTC crystal oscillator, GPIO clock output and 4MHz RC clock for power management
  • System LED outputs indicating device power state, and fault status
Package Options
  • 8 x 8 x 0.85mm, 81-lead QFN package

Parametric Specifications

Switching Frequency Selectable (2 or 4 MHz)
GPIOs 12
DC-DC Step-Down/Step-Up 4/0
LDO 13
Battery Charger false
Package 81 QFN

Software and Tools

WM8325 Setup

Oct 8, 2018, Rev 2.0 : 1.9Mb

WM8326 WISCE Install Kit

Oct 8, 2018, Rev 1 : 1.9 Mb


Comprehensive Solutions