ACT8870 datasheet(22/49 Pages) QORVO

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ACT8870

Advanced PMU for Microcontrollers

and Solid State Drive Applications

Data Sheet Rev. 7.0, Feb. 18, 2020 | Subject to change without notice

22 of 49

www.qorvo.com

SYSTEM CONTROL INFORMATION

General

The ACT8870 is a single-chip integrated power

management

solution

designed

power

many

processors such as the Atmel SAMA5D3. It integrates

four highly efficient buck regulators, three LDOs, and an

integrated load bypass switch. Its high integration and

high switching frequency result in an extremely small

footprint and lost power solution. It contains a master

controller that manages startup sequencing, timing,

voltages, slew rates, sleep states, and fault conditions.

I2C configurability allows system level changes without

the need for costly PCB changes. The built-in load

bypass switch enables full sequencing configurability in

3.3V systems.

The ACT8870 master controller monitors all outputs and

reports faults via I2C and hardwired status signals.

Faults can masked and fault levels and responses are

configurable via I2C.

Many

the

ACT8870 pins

and functions

are

configurable. The IC’s default functionality is defined by

the default CMI (Code Matrix Index), but much of this

functionality can be changed via I2C. The first part of

the datasheet describes basic IC functionality and

default pin functions. The end of the datasheet provides

the configuration and functionality specific to each CMI

version. Contact sales@active-semi.com for additional

information about other configurations.

I2C Serial Interface

To ensure compatibility with a wide range of systems,

the ACT8870 uses standard I2C commands. The

ACT8870 operates as a slave device, and is addressed

using a 7-bit slave address followed by an eighth bit,

which indicates whether the transaction is a read-

operation or a write-operation. As an example, the 7-bit

slave address 0x5Ah follows the format 1011010x

where “x” is a 0 for write operation and 1 for a read

operation. This results in 0xB4h for write operations and

0xB5h for read operations. Refer to each specific CMI

for the IC’s slave address

7-Bit Slave Address

8-Bit Write

Address

8-Bit Read

Address

0x5Ah

101 1010b

0xB4h

0xB5h

0x5Bh

101 1011b

0xB6h

0xB7h

0x53h

101 0011b

0xA6h

0xA7h

0x55h

101 0101b

0xAAh

0xABh

There is no timeout function in the I2C packet

processing state machine, however, any time the I2C

state machine receives a start bit command, it

immediately resets the packet processing, even if it is in

the middle of a valid packet.

The ACT8870 holds the I2C state machine in reset

during the RESET, Idle, OVUVFLT, and THERMAL

states to avoid a corruption of registers when the

voltage regulators are out of spec.

I2C commands are communicated using the SCL and

SDA pins. SCL is the I2C serial clock input. SDA is the

data input and output. SDA is open drain and must have

a pullup resistor. Signals on these pins must meet timing

requirements in the Electrical Characteristics Table.

I2C Registers

The ACT8870 contains an array of internal registers

contain the IC’s basic instructions for setting up the IC

configuration,

output

voltages,

sequencing,

fault

thresholds, fault masks, etc. These registers are what

give the IC its operating flexibility. The two types of

registers are described below.

Basic Volatile – These are R/W (Read and Write) and

RO (Read only). After the IC is powered, the user can

modify

the

R/W

values

change

functionality. Changes in functionality include things like

masking certain faults. The RO registers communicate

IC status such as fault conditions. Any changes to these

registers are lost when power is recycled. The default

values are fixed and cannot be changed by the factory

or the end user.

Basic Non-Volatile – These are R/W and RO. After the

IC is powered, the user can modify the R/W register

values

change

functionality.

Changes

functionality include things like output voltage settings,

startup delay time, and current limit thresholds. Any

changes to these registers are lost when power is

recycled. The default values can be modified at the

factory

optimize

functionality

for

specific

applications. Please consult sales@active-semi.com for

custom options and minimum order quantities.

When modifying only certain bits within a register, take

care

not

inadvertently

change

other

bits.

Inadvertently changing register contents can lead to

unexpected device behavior.

State Machine

The ACT8870 contains an internal state machine with

five internal states.

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