ACT5880 datasheet(68/87 Pages) ACTIVE-SEMI

68 / 87 page

ACT5880

Rev 2, 03-Sep-13

- 68 -

www.active-semi.com

ActivePMU

TM and ActivePathTM are trademarks of Active-Semi.

I2CTM is a trademark of NXP.

Active-Semi Confidential―Do Not Copy or Distribute

General Description

There are total 13 low drop-out linear regulators in

the ACT5880. Except for the one for backup battery

charger and the always-on LDO, the rest 11 LDOs

have similar way to control and to program through

the access of sets of registers, but the one tied for

REG2 has an additional control access though a

joint manipulation. Refer to Table 5 for a quick

summary of output currents and default output

voltages for each LDOs.

Table 5

The Key Specifications of LDOs.

The OUT6 and the OUT9 also have pin control

inputs for controlling their on/off together with the

on/off bit controls through the register access.

When both the ON bit and ON pin input are used for

control, the later change takes effect. Upon the

power up, if the default of ON bit is different than

the ON pin input, the OUT is ON. In other words,

the OUT upon power on is off only both the ON bit

and ON pin input are set for off. This arbitration is

enough and does well to most cases. However, if

one input sets the OUT to have a status that it

already outputs for in the condition that the OUT

sets for the complementary status by other input,

the input should send out a toggle, instead of repeat

the same logic volume.

Output Current Limit

Each LDO contains current-limit circuitry featuring a

current-limit fold-back function. During normal and

moderate overload conditions, the regulators can

support more than their rated output currents.

During extreme overload conditions, however, the

current limit is reduced by approximately 30%,

reducing power dissipation within the IC.

Configuration Options

Output Voltage Programming

By default, each LDO powers up and regulates to

its default output voltage. Once the system is

enabled, each output voltage may be independently

programmed to a different value by writing to the

regulator's VSET[-] register via the I2C serial

interface as shown in the STEP-DOWN DC/DC

and LDO OUTPUT VOLTAGE SETTING table.

Enable / Disable Control

During normal operation, each LDO may be

enabled or disabled via the I2C interface by writing

to that LDO's ON[ ] bit. To enable the LDO set ON[ ]

to 1, to disable the LDO clear ON[ ] to 0.

Output Discharge

Each of the ACT5880’s LDOs features an optional

output discharge function, which discharges the

output to ground through a 1kΩ resistance when the

LDO is disabled. This feature may be enabled or

disabled by setting DIS[-] via; set DIS[-] to 1 to

enable this function, clear DIS[-] to 0 to disable it.

Low-Power Mode

Each of ACT5880's LDOs features a LOWIQ[-] bit

which, when set to 1, reduces the LDO's quiescent

current by about 30%, saving power and extending

battery lifetime.

OK[ ] and Output Fault Interrupt

Each LDO features a power-OK status bit that can

be read by the system microprocessor via the

interface. If an output voltage is lower than the

power-OK threshold, typically 7% below the

programmed regulation voltage, the value of that

regulator's OK[-] bit will be 0.

If a LDO's nFLTMSK[-] bit is set to 1, the ACT5880

will interrupt the processor if that LDO's output

voltage falls below the power-OK threshold. In this

case, nIRQ will assert low and remain asserted until

the OK[-] bit has been read via I2C.

LOW-NOISE, LOW-DROPOUT LINEAR REGULATORS

NAME

DEFAULT

STATUS

REG4

REG5

REG6

OFF

REG7

REG8

REG9

OFF

DEFAULT

OUTPUT(V)

2.9

3.0

2.5

1.2

MAXIMUM

OUTPUT

(mA)

360

250

360

250

REG10

3.3

150

REG11

OFF

1.8

REG12

OFF

1.8

250

REG13

OFF

2.8

150

LDO tied in

REG2

OFF

1.8

Backup Battery

Charger

2.7

Always-on LDO

1.8

3.5

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