ACT88321 datasheet(27/55 Pages) QORVO

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ACT88321

Advanced PMIC with 3 Bucks, 2 LDOs, and Load Bypass Switches

Datasheet Rev. D , June 17, 2022 | Subject to change without notice

27 of 55

www.qorvo.com

Sequencing

The ACT88321 provides the end user with extremely

versatile sequencing capability that can be optimized for

many different applications. Each of the five outputs has

five basic sequencing parameters: input trigger, turn-on

delay, turn-off delay, softstart time, and output voltage.

Each of these parameters is controlled via the ICs inter-

nal registers. Contact Qorvo for custom sequencing

configurations. Refer to the Qorvo Application Note de-

scribing the Register Map for full details on I2C function-

ality and programming ranges.

Turn on and Turn off Options. The ACT88321 pro-

vides several options for enabling the IC. These include

automatic power up when input power is applied as well

as power up with a digital input signal to a GPIO. The

GPIO can be configured to latch the IC on with an input

pulse or to be level triggered. Once powered on, the IC

can be turned off with either the GPIO or an I2C com-

mand.

Input trigger. The input trigger for a regulator is the

event that turns that regulator on. Each output can have

a separate input trigger. The input trigger can be the in-

ternal power ok (POK) signal from one of the other reg-

ulators, the internal VIN POK signal, or an external sig-

nal applied to a GPIO. This flexibility allows a wide

range of sequencing possibilities, including having

some of the outputs be sequenced with another external

power supply or a control signal from the host. As an

example, if the LDO1 input trigger is Buck1, LDO1 will

not turn on until Buck1 is in regulation. Input triggers are

defined at the factory and can be changed with a cus-

tom CMI configuration. The GPIOs can be internally

connected to a power supply’s internal POK signal and

used as an output to turn on external supplies in the

overall sequencing scheme.

Turn-on Delay. The turn-on delay is the time between

an input trigger going active and the output starting to

turn on. Each output’s turn-on delay is configured via its

I2C bit ON_DELAY. Turn-on delays can be changed af-

ter the IC is powered on, but they are volatile and reset

to the factory defaults when power is recycled.

Turn-off Delay. The turn-off delay is the time between

the input trigger for SLEEP or DPSLP Mode being as-

serted and when each output starts to turn off. Each out-

put’s turn-off delay is configured via its I2C bit OFF_DE-

LAY. Turn-off delays can be changed after the IC is

powered on, but they are volatile and reset to the factory

defaults when power is recycled.

Softstart Time. The softstart time is the time it takes an

output to ramp from 10% to 90% to its programmed volt-

age. Each output’s softstart time is configured sepa-

rately via its I2C softstart bits. Softstart times can be

changed after the IC is powered on, but they are volatile

and reset to the factory defaults when power is recycled.

Output Voltage. Each buck’s output voltage is pro-

grammed via its I2C bits Bx_VSET0 and Bx_VSET1.

Note that in all conditions Bx_VSET0 must be pro-

grammed to a higher voltage than Bx_VSET1. Buck2

regulates to its B2_VSET0 voltage in ACTIVE mode. It

can be programmed to regulate to B2_VSET1 in DVS

mode, SLEEP state or by a GPIO input. Buck2 can

change between B2_VSET0 and B2_VSET1 on-the-fly.

Buck1/3 cannot change between Bx_VSET0 and

Bx_SET1 on-the-fly. Typically, Buck1/3 operate at the

Bx_VSET0 voltage. If a system requires two different

voltage options, a GPIO can be programmed as a volt-

age pinstrap input. The pinstrap input must be set be-

fore the output is enabled. The pinstrap input cannot be

changed while the converter is running. If the input is a

logic L, Buck1/3 operates from Bx_VSET0 and if the in-

put is a logic H, Buck1/3 operate from VSET1. This po-

larity can be reversed. The LDOs only have a single reg-

ister, LDOx_VSET, to set their output voltage.

Each output’s Bx_VSET0 and Bx_VSET1 voltage can

be changed via I2C after the IC is powered on, but the

new setting is volatile and is reset to the factory defaults

when power is recycled. All bucks and LDO output volt-

ages can be changed on-the-fly by writing a new value

into their I2C registers. The Buck1 and Buck3 output

voltage should only be changed by the minimum step

size for each I2C write. The Buck2, LDO1, and LDO2

output voltages can be changed with larger step sizes,

but Qorvo recommends minimizing the step size

change to prevent the IC from detecting an instantane-

ous over or under voltage condition due to fault thresh-

olds being immediately changed, but output voltage tak-

ing time to respond.

Dynamic Voltage Scaling

On-the-fly dynamic voltage scaling (DVS) for Buck2 is

available via the I2C interface. Note that Buck1/3 output

voltage cannot be changed on-the-fly. DVS allows sys-

tems to save power by quickly adjusting the micropro-

cessor performance level when the workload changes.

Note that DVS is not a different operating state. The IC

operates in the ACTIVE state, but just regulates the out-

puts to a different voltage. For fault free operation, the

user must ensure output load conditions plus the current

required to charge the output capacitance during a DVS

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