Datasheet - Active-Semi

ACT8938
®
Rev 3, 23-Dec-11
Advanced PMU for Marvell Aspen
FEATURES
GENERAL DESCRIPTION
•
•
•
•
•
•
•
•
The ACT8938 is a complete, cost effective, highly
efficient ActivePMUTM power management solution,
optimized for the unique power, voltage
sequencing, and control requirements of the Marvell
Aspen processor.
Optimized for Marvell Aspen Processors
Three Step-Down DC/DC Converters
Four Low-Dropout Linear Regulators
Integrated ActivePathTM Charger
I2CTM Serial Interface
Advanced Enable/Disable Sequencing Controller
Minimal External Components
Tiny 5×5mm TQFN55-40 Package
− 0.75mm Package Height
− Pb-Free and RoHS Compliant
This device features three step-down DC/DC
converters and four low-noise, low-dropout linear
regulators, along with a complete battery charging
solution featuring the advanced ActivePathTM
system-power selection function.
The three DC/DC converters utilize a high
efficiency, fixed-frequency (2MHz), current-mode
PWM control architecture that requires a minimum
number of external components. Two DC/DCs are
capable of supplying up to 1150mA of output
current, while the third supports up to 1300mA. All
four low-dropout linear regulators are highperformance, low-noise regulators that supply up to
150mA, 150mA, 320mA and 320mA respectively.
The ACT8938 is available in a compact, Pb-Free
and RoHS-compliant TQFN55-40 package .
TYPICAL APPLICATION DIAGRAM
Active-Semi
Innovative PowerTM
Active-Semi Proprietary―For Authorized Recipients and Customers
ActivePMUTM and ActivePathTM are trademarks of Active-Semi.
I2CTM is a trademark of NXP.
Marvell
Aspen
-1-
www.active-semi.com
Copyright © 2011 Active-Semi, Inc.
ACT8938
®
Rev 3, 23-Dec-11
TABLE OF CONTENTS
General Information ..................................................................................................................................... p. 01
Functional Block Diagram ............................................................................................................................ p. 03
Ordering Information .................................................................................................................................... p. 04
Pin Configuration ......................................................................................................................................... p. 04
Pin Descriptions ........................................................................................................................................... p. 05
Absolute Maximum Ratings ......................................................................................................................... p. 07
I2C Interface Electrical Characteristics ........................................................................................................ p. 08
Global Register Map .................................................................................................................................... p. 09
Register and Bit Descriptions ...................................................................................................................... p. 10
System Control Electrical Characteristics.................................................................................................... p. 15
Step-Down DC/DC Electrical Characteristics .............................................................................................. p. 16
Low-Noise LDO Electrical Characteristics ................................................................................................... p. 17
ActivePathTM Charger Electrical Characteristics.......................................................................................... p. 18
Typical Performance Characteristics ........................................................................................................... p. 20
System control information .......................................................................................................................... p. 28
Interfacing with the Marvell Aspen ................................................................................................... p. 28
Control Signals ................................................................................................................................. p. 29
Push-Button Control ......................................................................................................................... p. 30
Control Sequences ........................................................................................................................... p. 30
Functional Description ................................................................................................................................. p. 33
I2C Interface ..................................................................................................................................... p. 33
Voltage Monitor and Interrupt........................................................................................................... p. 33
Thermal Shutdown ........................................................................................................................... p. 34
Step-own DC/DC Regulators ....................................................................................................................... p. 35
General Description.......................................................................................................................... p. 35
100% Duty Cycle Operation ............................................................................................................. p. 35
Synchronous Rectification ................................................................................................................ p. 35
Soft-Start .......................................................................................................................................... p. 35
Compensation .................................................................................................................................. p. 35
Configuration Options....................................................................................................................... p. 35
OK[ ] and Output Fault Interrupt ....................................................................................................... p. 36
PCB Layout Considerations ............................................................................................................. p. 36
Low-Noise, Low-Dropout Linear Regulators................................................................................................ p. 37
General Description.......................................................................................................................... p. 37
Output Current Limit ......................................................................................................................... p. 37
Compensation .................................................................................................................................. p. 37
Configuration Options....................................................................................................................... p. 37
OK[ ] and Output Fault Interrupt ....................................................................................................... p. 37
PCB Layout Considerations ............................................................................................................. p. 38
ActivePathTM Charger .................................................................................................................................. p. 39
General Description.......................................................................................................................... p. 39
ActivePath Architecture .................................................................................................................... p. 39
System Configuration Optimization .................................................................................................. p. 39
Input Protection ................................................................................................................................ p. 39
Battery Management ........................................................................................................................ p. 39
Charge Current Programming .......................................................................................................... p. 40
Charge Input Interrupts .................................................................................................................... p. 40
Charge-Control State Machine ......................................................................................................... p. 42
State Machine Interrupts .................................................................................................................. p. 42
Thermal Regulation .......................................................................................................................... p. 43
Charge Safety Timers ...................................................................................................................... p. 43
Charge Timer Interrupts ................................................................................................................... p. 43
Charge Status Indicator.................................................................................................................... p. 43
Reverse-Current Protection ............................................................................................................. p. 43
Battery Temperature Monitoring ...................................................................................................... p. 43
Battery Temperature Interrupts ........................................................................................................ p. 44
TQFN55-40 Package Outline and Dimensions ........................................................................................... p. 45
Innovative PowerTM
Active-Semi Proprietary―For Authorized Recipients and Customers
ActivePMUTM and ActivePathTM are trademarks of Active-Semi.
I2CTM is a trademark of NXP.
-2-
www.active-semi.com
Copyright © 2011 Active-Semi, Inc.
ACT8938
®
Rev 3, 23-Dec-11
FUNCTIONAL BLOCK DIAGRAM
(Optional)
AC Adaptor
Active-Semi
BODY
SWITCH
ACT8938
4.35V to 6V CHGIN
VSYS
System Supply
BAT
Li+ Battery
USB
ACIN
BODY
SWITCH
ActivePath
Control
VSYS
nSTAT
+
102µA
CURRENT SENSE
CHARGE STATUS
TH
VOLTAGE SENSE
Charge
Control
CHGLEV
PRECONDITION
2.85V
VP1
ISET
THERMAL
REGULATION
OUT2
To VSYS
110°C
SW1
OUT1
nRSTO
OUT1
VSYS
GP12
nPBIN
PUSH BUTTON
VP2
OUT2
To VSYS
SW2
nPBSTAT
OUT2
OUT2
OUT2
GP12
nIRQ
VP3
To VSYS
SW3
PWRHLD
OUT3
OUT3
System
Control
nHIB
GP3
VSEL
INL
SCL
REG4
LDO
SDA
BAT
LBI
1.2V
VSYS
REG5
LDO
+
REG6
LDO
nLBO
REG7
LDO
REFBP
To VSYS
OUT4
OUT4
OUT5
OUT5
OUT6
OUT6
OUT7
OUT7
Reference
GA
Innovative PowerTM
Active-Semi Proprietary―For Authorized Recipients and Customers
ActivePMUTM and ActivePathTM are trademarks of Active-Semi.
I2CTM is a trademark of NXP.
EP
-3-
www.active-semi.com
Copyright © 2011 Active-Semi, Inc.
ACT8938
®
Rev 3, 23-Dec-11
ORDERING INFORMATION
PART NUMBER VOUT1/VSTBY1 VOUT2/VSTBY2 VOUT3/VSTBY3 VOUT4 VOUT5 VOUT6 VOUT7 PACKAGE PINS
TEMPERATURE
RANGE
ACT8938QJ133-T 1.8V/1.8V
3.3V/3.3V
1.2V/1.1V 1.8V 3.3V 3.3V 3.3V TQFN55-40 40
-40°C to +85°C
ACT8938QJ131-T 1.8V/1.8V
3.3V/3.3V
1.1V/1.0V 1.8V 3.3V 3.3V 3.3V TQFN55-40 40
-40°C to +85°C
: All Active-Semi components are RoHS Compliant and with Pb-free plating unless otherwise specified.
: Standard product options are listed in this table. Contact factory for custom options. Minimum order quantity is 12,000 units.
: To select VSTBYx as the output regulation voltage for REGx, drive VSEL to logic high. VSTBYx can be set by software via I2C interface.
Refer to appropriate sections of this datasheet for VSTBYx setting.
ACT8938QJ_ _ _-T
Active-Semi
Product Number
Package Code
Pin Count
Option Code
Tape and Reel
PIN CONFIGURATION
VSYS
CHGIN
VSYS
OUT2
VP2
SW2
GP12
SW1
VP1
NC
TOP VIEW
REFBP
BAT
OUT1
BAT
GA
nSTAT
OUT4
SDA
ACTIVE
AA33
DATE CODE
OUT5
INL
OUT7
SCL
VSEL
TH
OUT6
ISET
nPBIN
CHGLEV
EP
LBI
nLBO
PWREN
OUT3
VP3
SW3
GP3
nPBSTAT
nIRQ
ACIN
nRSTO
PWRHLD
Thin - QFN (TQFN55-40)
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Active-Semi Proprietary―For Authorized Recipients and Customers
ActivePMUTM and ActivePathTM are trademarks of Active-Semi.
I2CTM is a trademark of NXP.
-4-
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Copyright © 2011 Active-Semi, Inc.
ACT8938
®
Rev 3, 23-Dec-11
PIN DESCRIPTIONS
PIN
NAME
DESCRIPTION
1
REFBP
2
OUT1
3
GA
4
OUT4
REG4 output. Capable of delivering up to 150mA of output current. Connect a 1.5µF ceramic
capacitor from OUT4 to GA. The output is discharged to GA with 1.5kΩ resistor when disabled.
5
OUT5
REG5 output. Capable of delivering up to 150mA of output current. Connect a 1.5µF ceramic
capacitor from OUT5 to GA. The output is discharged to GA with 1.5kΩ resistor when disabled.
6
INL
7
OUT7
REG7 output. Capable of delivering up to 320mA of output current. Connect a 3.3µF ceramic
capacitor from OUT7 to GA. The output is discharged to GA with 1.5kΩ resistor when disabled.
8
OUT6
REG6 output. Capable of delivering up to 320mA of output current. Connect a 3.3µF ceramic
capacitor from OUT6 to GA. The output is discharged to GA with 1.5kΩ resistor when disabled.
9
nPBIN
Master Enable Input. Drive nPBIN to GA through a 50kΩ resistor to enable the IC, drive nPBIN
directly to GA to assert a manual reset condition. Refer to the nPBIN Multi-Function Input section
for more information. nPBIN is internally pulled up to VSYS through a 35kΩ resistor.
10
PWRHLD
Power Hold Input. Refer to the Control Sequences section for more information.
11
nRSTO
Active Low Reset Output. See the nRSTO Output section for more information.
12
nIRQ
13
nPBSTAT
14
GP3
Power Ground for REG3. Connect GA, GP12, and GP3 together at a single point as close to the
IC as possible.
15
SW3
Switching Node Output for REG3.
16
VP3
Power Input for REG3. Bypass to GP3 with a high quality ceramic capacitor placed as close to the
IC as possible.
17
OUT3
Output Feedback Sense for REG3.
18
nHIB
Hibernate Mode Input. Refer to the Control Sequences section for more information.
19
nLBO
Low Battery Indicator Output. nLBO is asserted low whenever the voltage at LBI is lower than
1.2V, and is high-Z otherwise. See the Precision Voltage Detector section for more information.
20
LBI
21
ACIN
22
CHGLEV
Reference Bypass. Connect a 0.047μF ceramic capacitor from REFBP to GA. This pin is
discharged to GA in shutdown.
Output Feedback Sense for REG1. Connect this pin directly to the output node to connect the
internal feedback network to the output voltage.
Analog Ground. Connect GA directly to a quiet ground node. Connect GA, GP12 and GP3
together at a single point as close to the IC as possible.
Power Input for REG4, REG5, REG6, and REG7. Bypass to GA with a high quality ceramic
capacitor placed as close to the IC as possible.
Open-Drain Interrupt Output. nIRQ is asserted any time an unmasked fault condition exists or a
charger interrupt occurs. See the nIRQ Output section for more information.
Active-Low Open-Drain Push-Button Status Output. nPBSTAT is asserted low whenever the
nPBIN is pushed, and is high-Z otherwise. See the nPBSTAT Output section for more information.
Low Battery Input. The input voltage is compared to 1.2V and the output of this comparison drives
nLBO. See the Precision Voltage Detector section for more information.
AC Input Supply Detection. See the Charge Current Programming section for more information.
Charge Current Selection Input. See the Charge Current Programming section for more information.
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Active-Semi Proprietary―For Authorized Recipients and Customers
ActivePMUTM and ActivePathTM are trademarks of Active-Semi.
I2CTM is a trademark of NXP.
-5-
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Copyright © 2011 Active-Semi, Inc.
ACT8938
®
Rev 3, 23-Dec-11
PIN DESCRIPTIONS CONT’D
PIN
NAME
DESCRIPTION
23
ISET
24
TH
Temperature Sensing Input. Connect to battery thermistor. TH is pulled up with a 102µA (typ) current
internally. See the Battery Temperature Monitoring section for more information.
25
VSEL
Step-Down DC/DCs Output Voltage Selection. Drive to logic low to select default output voltage.
Drive to logic high to select secondary output voltage. See the Output Voltage Programming
section for more information.
26
SCL
Clock Input for I2C Serial Interface.
27
SDA
Data Input for I2C Serial Interface. Data is read on the rising edge of SCL.
28
nSTAT
29, 30
BAT
31, 32
VSYS
System Output Pin. Bypass to GA with a 10µF or larger ceramic capacitor.
33
CHGIN
Power Input for the Battery Charger. Bypass CHGIN to GA with a capacitor placed as close to
the IC as possible. The battery charger is automatically enabled when a valid voltage is present
on CHGIN.
34
OUT2
Output Feedback Sense for REG2.
35
VP2
Power Input for REG2. Bypass to GP12 with a high quality ceramic capacitor placed as close to
the IC as possible.
36
SW2
Switching Node Output for REG2.
37
GP12
Power Ground for REG1 and REG2. Connect GA, GP12 and GP3 together at a single point as
close to the IC as possible.
38
SW1
Switching Node Output for REG1.
39
VP1
Power Input for REG1. Bypass to GP12 with a high quality ceramic capacitor placed as close to
the IC as possible.
40
NC
No Connect. Not internally connected.
EP
EP
Exposed Pad. Must be soldered to ground on PCB.
Charge Current Set. Program the charge current by connecting a resistor (RISET) between ISET
and GA. See the Charge Current Programming section for more information.
Active-Low Open-Drain Charger Status Output. nSTAT has a 8mA (typ) current limit, allowing it
to directly drive an indicator LED without additional external components. See the Charge Status
Indicator section for more information.
Battery Charger Output. Connect this pin directly to the battery anode (+ terminal)
Innovative PowerTM
Active-Semi Proprietary―For Authorized Recipients and Customers
ActivePMUTM and ActivePathTM are trademarks of Active-Semi.
I2CTM is a trademark of NXP.
-6-
www.active-semi.com
Copyright © 2011 Active-Semi, Inc.
ACT8938
®
Rev 3, 23-Dec-11
ABSOLUTE MAXIMUM RATINGS
PARAMETER
VALUE
UNIT
VP1, VP2 to GP12
VP3 to GP3
-0.3 to +6
V
BAT, VSYS, INL to GA
-0.3 to +6
V
CHGIN to GA
-0.3 to +14
V
SW1, OUT1 to GP12
-0.3 to (VVP1 + 0.3)
V
SW2, OUT2 to GP12
-0.3 to (VVP2 + 0.3)
V
SW3, OUT3 to GP3
-0.3 to (VVP3 + 0.3)
V
-0.3 to +6
V
nPBIN, ACIN, CHGLEV, ISET, LBI, PWRHLD, nHIB, REFBP, SCL, SDA, TH, VSEL to
GA
-0.3 to (VSYS+0.3)
V
OUT4, OUT5, OUT6, OUT7 to GA
-0.3 to (VINL + 0.3)
V
-0.3 to +0.3
V
Operating Ambient Temperature
-40 to 85
°C
Maximum Junction Temperature
125
°C
Maximum Power Dissipation
TQFN55-40 (Thermal Resistance θJA = 30oC/W)
2.7
W
-65 to 150
°C
300
°C
nIRQ, nLBO, nPBSTAT, nRSTO, nSTAT to GA
GP12, GP3 to GA
Storage Temperature
Lead Temperature (Soldering, 10 sec)
: Do not exceed these limits to prevent damage to the device. Exposure to absolute maximum rating conditions for long periods may
affect device reliability.
Innovative PowerTM
Active-Semi Proprietary―For Authorized Recipients and Customers
ActivePMUTM and ActivePathTM are trademarks of Active-Semi.
I2CTM is a trademark of NXP.
-7-
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Copyright © 2011 Active-Semi, Inc.
ACT8938
®
Rev 3, 23-Dec-11
I2C INTERFACE ELECTRICAL CHARACTERISTICS
(VVSYS = 3.6V, TA = 25°C, unless otherwise specified.)
PARAMETER
TEST CONDITIONS
MIN
SCL, SDA Input Low
VVSYS = 3.1V to 5.5V, TA = -40ºC to 85ºC
SCL, SDA Input High
VVSYS = 3.1V to 5.5V, TA = -40ºC to 85ºC
TYP
UNIT
0.35
V
1.55
V
SDA Leakage Current
SCL Leakage Current
8
SDA Output Low
MAX
IOL = 5mA
1
µA
18
µA
0.35
V
SCL Clock Period, tSCL
1.5
µs
SDA Data Setup Time, tSU
100
ns
SDA Data Hold Time, tHD
300
ns
Start Setup Time, tST
For Start Condition
100
ns
Stop Setup Time, tSP
For Stop Condition
100
ns
Figure 1:
I2C Compatible Serial Bus Timing
tSCL
SCL
tST
tHD
tSU
tSP
SDA
Start
condition
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Active-Semi Proprietary―For Authorized Recipients and Customers
ActivePMUTM and ActivePathTM are trademarks of Active-Semi.
I2CTM is a trademark of NXP.
Stop
condition
-8-
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Copyright © 2011 Active-Semi, Inc.
ACT8938
®
Rev 3, 23-Dec-11
GLOBAL REGISTER MAP
BITS
OUTPUT ADDRESS
SYS
0x00
SYS
0x01
REG1
REG1
0x20
0x21
REG1
0x22
REG2
0x30
REG2
REG2
0x31
0x32
REG3
0x40
REG3
0x41
REG3
REG4
0x42
0x50
REG4
0x51
REG5
0x54
REG5
REG6
0x55
0x60
REG6
0x61
REG7
0x64
REG7
APCH
0x65
0x70
APCH
0x71
APCH
0x78
APCH
APCH
0x79
0x7A
D7
NAME
DEFAULT
NAME
DEFAULT
NAME
DEFAULT
NAME
DEFAULT
NAME
DEFAULT
NAME
DEFAULT
NAME
DEFAULT
NAME
DEFAULT
NAME
DEFAULT
NAME
DEFAULT
NAME
DEFAULT
NAME
DEFAULT
NAME
DEFAULT
NAME
DEFAULT
NAME
DEFAULT
NAME
DEFAULT
NAME
DEFAULT
NAME
DEFAULT
NAME
DEFAULT
NAME
DEFAULT
NAME
DEFAULT
NAME
DEFAULT
NAME
DEFAULT
NAME
DEFAULT
TRST
D6
D5
D4
nSYSMODE nSYSLEVMSK nSYSSTAT
D3
SYSLEV[3]
D2
D1
SYSLEV[2] SYSLEV[1]
D0
SYSLEV[0]
1
1
0
R
0
1
1
1
Reserved
FRC_ON1
Reserved
Reserved
SCRATCH
SCRATCH
HBRDY
SCRATCH
0
0
0
0
0
0
0
0
Reserved
Reserved
VSET1[5]
VSET1[4]
VSET1[3]
VSET1[2]
VSET1[1]
VSET1[0]
0
0
1
0
0
1
0
0
Reserved
Reserved
VSET2[5]
VSET2[4]
VSET2[3]
VSET2[2]
VSET2[1]
VSET2[0]
0
0
1
0
0
1
0
0
ON
PHASE
MODE
DELAY[2]
DELAY[1]
DELAY[0]
nFLTMSK
OK
0
0
0
0
1
0
0
R
Reserved
Reserved
VSET1[5]
VSET1[4]
VSET1[3]
VSET1[2]
VSET1[1]
VSET1[0]
0
0
1
1
1
0
0
1
Reserved
Reserved
VSET2[5]
VSET2[4]
VSET2[3]
VSET2[2]
VSET2[1]
VSET2[0]
0
0
1
1
1
0
0
1
ON
PHASE
MODE
DELAY[2]
DELAY[1]
DELAY[0]
nFLTMSK
OK
0
0
0
0
0
0
0
R
Reserved
Reserved
VSET1[5]
VSET1[4]
VSET1[3]
VSET1[2]
VSET1[1]
VSET1[0]
0
0
0
1
1
0
0
0
Reserved
Reserved
VSET2[5]
VSET2[4]
VSET2[3]
VSET2[2]
VSET2[1]
VSET2[0]
0
0
0
1
0
1
0
0
ON
Reserved
MODE
DELAY[2]
DELAY[1]
DELAY[0]
nFLTMSK
OK
0
0
0
0
0
1
0
R
Reserved
Reserved
VSET[5]
VSET[4]
VSET[3]
VSET[2]
VSET[1]
VSET[0]
0
0
1
0
0
1
0
0
ON
DIS
LOWIQ
DELAY[2]
DELAY[1]
DELAY[0]
nFLTMSK
OK
0
1
0
0
0
0
0
R
Reserved
Reserved
VSET[5]
VSET[4]
VSET[3]
VSET[2]
VSET[1]
VSET[0]
0
0
1
1
1
0
0
1
ON
DIS
LOWIQ
DELAY[2]
DELAY[1]
DELAY[0]
nFLTMSK
OK
0
1
0
0
1
1
0
R
Reserved
Reserved
VSET[5]
VSET[4]
VSET[3]
VSET[2]
VSET[1]
VSET[0]
0
0
1
1
1
0
0
1
ON
DIS
LOWIQ
DELAY[2]
DELAY[1]
DELAY[0]
nFLTMSK
OK
0
1
0
0
0
0
0
R
Reserved
Reserved
VSET[5]
VSET[4]
VSET[3]
VSET[2]
VSET[1]
VSET[0]
0
0
1
1
1
0
0
1
ON
DIS
LOWIQ
DELAY[2]
DELAY[1]
DELAY[0]
nFLTMSK
OK
0
1
0
0
0
0
0
R
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
0
1
0
0
0
0
1
SUSCHG
Reserved
0
0
TIMRSTAT TEMPSTAT
TOTTIMO[1] TOTTIMO[0] PRETIMO[1] PRETIMO[0] OVPSET[1]
0
OVPSET[0]
1
0
1
0
0
0
CHGDAT
INSTAT
CHGSTAT
TIMRDAT
TEMPDAT
INDAT
0
0
0
0
R
R
R
R
TIMRTOT
TEMPIN
INCON
CHGEOCIN
TIMRPRE
TEMPOUT
INDIS
CHGEOCOUT
0
0
0
0
0
0
0
0
Reserved
Reserved
CSTATE[0]
CSTATE[1]
Reserved
Reserved
ACINSTAT
Reserved
0
0
R
R
R
R
R
R
: Default values of ACT8938QJ133-T.
2: All bits are automatically cleared to default values when the input power is removed or falls below the system UVLO.
Innovative PowerTM
Active-Semi Proprietary―For Authorized Recipients and Customers
ActivePMUTM and ActivePathTM are trademarks of Active-Semi.
I2CTM is a trademark of NXP.
-9-
www.active-semi.com
Copyright © 2011 Active-Semi, Inc.
ACT8938
®
Rev 3, 23-Dec-11
REGISTER AND BIT DESCRIPTIONS
Table 1:
Global Register Map
OUTPUT ADDRESS BIT
NAME
ACCESS
DESCRIPTION
SYS
0x00
[7]
TRST
R/W
Reset Timer Setting. Defines the reset time-out threshold. Reset
time-out is 65ms when value is 1, reset time-out is 260ms when
value is 0. See nRSTO Output section for more information.
SYS
0x00
[6]
nSYSMODE
R/W
SYSLEV Mode Select. Defines the response to the SYSLEV
voltage detector, 1: Generate an interrupt when VVSYS falls below
the programmed SYSLEV threshold, 0: automatic shutdown
when VVSYS falls below the programmed SYSLEV threshold.
R/W
System Voltage Level Interrupt Mask. SYSLEV interrupt is
masked by default, set to 1 to unmask this interrupt. See the
Programmable System Voltage Monitor section for more
information
SYS
0x00
[5] nSYSLEVMSK
SYS
0x00
[4]
nSYSSTAT
R
System Voltage Status. Value is 1 when VVSYS is lower than the
SYSLEV voltage threshold, value is 0 when VVSYS is higher than
the system voltage detection threshold.
SYS
0x00
[3:0]
SYSLEV
R/W
System Voltage Detect Threshold. Defines the SYSLEV voltage
threshold. See the Programmable System Voltage Monitor
section for more information.
SYS
0x01
[7]
-
R/W
Reserved.
SYS
0x01
[6]
FRC_ON1
R/W
Force-On bit for REG1. Set bit to 1 before entering Hibernate
mode to keep REG1 ON during Hibernate even when PWRHLD
is de-asserted. Clear bit to 0 after waking from Hibernate mode.
SYS
0x01
[5:4]
-
R/W
Reserved.
SYS
0x01
[3:2]
SCRATCH
R/W
Scratchpad Bits. Non-functional bits, maybe be used by user to
store system status information. Volatile bits, which are cleared
when system voltage falls below UVLO threshold.
SYS
0x01
[1]
HBRDY
R/W
Hibernate Ready Flag. Set bit to 1 before entering
Hibernate mode, then read this bit during enable sequence
to identify system status: if bit value is 1 the system is
waking from Hibernate mode, if bit value is 0 the system is
waking from a disabled state.
SYS
0x01
[0]
SCRATCH
R/W
Scratchpad Bit. Non-functional bit, maybe be used by user to
store system status information. Volatile bit, which is cleared
when system voltage falls below UVLO threshold.
REG1
0x20
[7:6]
-
R
Reserved.
Primary Output Voltage Selection. Valid when VSEL is driven low.
See the Output Voltage Programming section for more
information.
REG1
0x20
[5:0]
VSET1
R/W
REG1
0x21
[7:6]
-
R
REG1
0x21
[5:0]
VSET2
R/W
Secondary Output Voltage Selection. Valid when VSEL is driven
high. See the Output Voltage Programming section for more
information.
REG1
0x22
[7]
ON
R/W
Regulator Enable Bit. Set bit to 1 to enable the regulator, clear bit
to 0 to disable the regulator.
REG1
0x22
[6]
PHASE
R/W
Regulator Phase Control. Set bit to 1 for the regulator to operate
180° out of phase with the oscillator, clear bit to 0 for the
regulator to operate in phase with the oscillator.
REG1
0x22
[5]
MODE
R/W
Regulator Mode Select. Set bit to 1 for fixed-frequency PWM
under all load conditions, clear bit to 0 to transit to power-savings
mode under light-load conditions.
REG1
0x22
[4:2]
DELAY
R/W
Regulator Turn-On Delay Control. See the REG1, REG2, REG3
Turn-on Delay section for more information.
Reserved.
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ACT8938
®
Rev 3, 23-Dec-11
REGISTER AND BIT DESCRIPTIONS CONT’D
OUTPUT
ADDRESS
BIT
NAME
ACCESS
DESCRIPTION
REG1
0x22
[1]
nFLTMSK
R/W
REG1
0x22
[0]
OK
R
Regulator Power-OK Status. Value is 1 when output voltage
exceeds the power-OK threshold, value is 0 otherwise.
REG2
0x30
[7:6]
-
R
Reserved.
REG2
0x30
[5:0]
VSET1
R/W
REG2
0x31
[7:6]
-
R
Regulator Fault Mask Control. Set bit to 1 enable faultinterrupts, clear bit to 0 to disable fault-interrupts.
Primary Output Voltage Selection. Valid when VSEL is driven
low. See the Output Voltage Programming section for more
information.
Reserved.
REG2
0x31
[5:0]
VSET2
R/W
Secondary Output Voltage Selection. Valid when VSEL is
driven high. See the Output Voltage Programming section for
more information.
REG2
0x32
[7]
ON
R/W
Regulator Enable Bit. Set bit to 1 to enable the regulator, clear
bit to 0 to disable the regulator.
REG2
0x32
[6]
PHASE
R/W
Regulator Phase Control. Set bit to 1 for the regulator to
operate 180° out of phase with the oscillator, clear bit to 0 for
the regulator to operate in phase with the oscillator.
REG2
0x32
[5]
MODE
R/W
Regulator Mode Select. Set bit to 1 for fixed-frequency PWM
under all load conditions, clear bit to 0 to transit to powersavings mode under light-load conditions.
REG2
0x32
[4:2]
DELAY
R/W
Regulator Turn-On Delay Control. See the REG1, REG2,
REG3 Turn-on Delay section for more information.
REG2
0x32
[1]
nFLTMSK
R/W
Regulator Fault Mask Control. Set bit to 1 enable faultinterrupts, clear bit to 0 to disable fault-interrupts.
REG2
0x32
[0]
OK
R
Regulator Power-OK Status. Value is 1 when output voltage
exceeds the power-OK threshold, value is 0 otherwise.
REG3
0x40
[7:6]
-
R
Reserved.
REG3
0x40
[5:0]
VSET1
R/W
REG3
0x41
[7:6]
-
R
Primary Output Voltage Selection. Valid when VSEL is driven
low. See the Output Voltage Programming section for more
information.
Reserved.
REG3
0x41
[5:0]
VSET2
R/W
Secondary Output Voltage Selection. Valid when VSEL is
driven high. See the Output Voltage Programming section for
more information.
REG3
0x42
[7]
ON
R/W
Regulator Enable Bit. Set bit to 1 to enable the regulator, clear
bit to 0 to disable the regulator.
REG3
0x42
[6]
-
R/W
Reserved.
REG3
0x42
[5]
MODE
R/W
Regulator Mode Select. Set bit to 1 for fixed-frequency PWM
under all load conditions, clear bit to 0 to transit to powersavings mode under light-load conditions.
REG3
0x42
[4:2]
DELAY
R/W
Regulator Turn-On Delay Control. See the REG1, REG2,
REG3 Turn-on Delay section for more information.
REG3
0x42
[1]
nFLTMSK
R/W
Regulator Fault Mask Control. Set bit to 1 enable faultinterrupts, clear bit to 0 to disable fault-interrupts.
REG3
0x42
[0]
OK
R
Regulator Power-OK Status. Value is 1 when output voltage
exceeds the power-OK threshold, value is 0 otherwise.
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ACT8938
®
Rev 3, 23-Dec-11
REGISTER AND BIT DESCRIPTIONS CONT’D
OUTPUT
ADDRESS
BIT
NAME
ACCESS
DESCRIPTION
REG4
0x50
[7:6]
-
R
REG4
0x50
[5:0]
VSET
R/W
Output Voltage Selection. See the Output Voltage
Programming section for more information.
REG4
0x51
[7]
ON
R/W
Regulator Enable Bit. Set bit to 1 to enable the regulator,
clear bit to 0 to disable the regulator.
Reserved.
REG4
0x51
[6]
DIS
R/W
Output Discharge Control. When activated, LDO output is
discharged to GA through 1.5kΩ resistor when in shutdown.
Set bit to 1 to enable output voltage discharge in shutdown,
clear bit to 0 to disable this function.
REG4
0x51
[5]
LOWIQ
R/W
LDO Low-IQ Mode Control. Set bit to 1 for low-power
operating mode, clear bit to 0 for normal mode.
REG4
0x51
[4:2]
DELAY
R/W
Regulator Turn-On Delay Control. See the REG4, REG5,
REG6, REG7 Turn-on Delay section for more information.
REG4
0x51
[1]
nFLTMSK
R/W
Regulator Fault Mask Control. Set bit to 1 enable faultinterrupts, clear bit to 0 to disable fault-interrupts.
REG4
0x51
[0]
OK
R
Regulator Power-OK Status. Value is 1 when output voltage
exceeds the power-OK threshold, value is 0 otherwise.
REG5
0x54
[7:6]
-
R
Reserved.
REG5
0x54
[5:0]
VSET
R/W
Output Voltage Selection. See the Output Voltage
Programming section for more information.
REG5
0x55
[7]
ON
R/W
Regulator Enable Bit. Set bit to 1 to enable the regulator,
clear bit to 0 to disable the regulator.
REG5
0x55
[6]
DIS
R/W
Output Discharge Control. When activated, LDO output is
discharged to GA through 1.5kΩ resistor when in shutdown.
Set bit to 1 to enable output voltage discharge in shutdown,
clear bit to 0 to disable this function.
REG5
0x55
[5]
LOWIQ
R/W
LDO Low-IQ Mode Control. Set bit to 1 for low-power
operating mode, clear bit to 0 for normal mode.
REG5
0x55
[4:2]
DELAY
R/W
Regulator Turn-On Delay Control. See the REG4, REG5,
REG6 , REG7 Turn-on Delay section for more information.
REG5
0x55
[1]
nFLTMSK
R/W
Regulator Fault Mask Control. Set bit to 1 enable faultinterrupts, clear bit to 0 to disable fault-interrupts.
REG5
0x55
[0]
OK
R
Regulator Power-OK Status. Value is 1 when output voltage
exceeds the power-OK threshold, value is 0 otherwise.
REG6
0x60
[7:6]
-
R
Reserved.
REG6
0x60
[5:0]
VSET
R/W
Output Voltage Selection. See the Output Voltage
Programming section for more information.
REG6
0x61
[7]
ON
R/W
Regulator Enable Bit. Set bit to 1 to enable the regulator,
clear bit to 0 to disable the regulator.
REG6
0x61
[6]
DIS
R/W
Output Discharge Control. When activated, LDO output is
discharged to GA through 1.5kΩ resistor when in shutdown.
Set bit to 1 to enable output voltage discharge in shutdown,
clear bit to 0 to disable this function.
REG6
0x61
[5]
LOWIQ
R/W
LDO Low-IQ Mode Control. Set bit to 1 for low-power
operating mode, clear bit to 0 for normal mode.
REG6
0x61
[4:2]
DELAY
R/W
Regulator Turn-On Delay Control. See the REG4, REG5,
REG6, REG7 Turn-on Delay section for more information.
REG6
0x61
[1]
nFLTMSK
R/W
Regulator Fault Mask Control. Set bit to 1 enable faultinterrupts, clear bit to 0 to disable fault-interrupts.
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ACT8938
®
Rev 3, 23-Dec-11
REGISTER AND BIT DESCRIPTIONS CONT’D
OUTPUT ADDRESS
BIT
NAME
ACCESS
REG6
0x61
[0]
OK
R
REG7
0x64
[7:6]
-
R
DESCRIPTION
Regulator Power-OK Status. Value is 1 when output voltage
exceeds the power-OK threshold, value is 0 otherwise.
Reserved.
REG7
0x64
[5:0]
VSET
R/W
Output Voltage Selection. See the Output Voltage
Programming section for more information.
REG7
0x65
[7]
ON
R/W
Regulator Enable Bit. Set bit to 1 to enable the regulator, clear
bit to 0 to disable the regulator.
REG7
0x65
[6]
DIS
R/W
Output Discharge Control. When activated, LDO output is
discharged to GA through 1.5kΩ resistor when in shutdown.
Set bit to 1 to enable output voltage discharge in shutdown,
clear bit to 0 to disable this function.
REG7
0x65
[5]
LOWIQ
R/W
LDO Low-IQ Mode Control. Set bit to 1 for low-power
operating mode, clear bit to 0 for normal mode.
REG7
0x65
[4:2]
DELAY
R/W
Regulator Turn-On Delay Control. See the REG4, REG5,
REG6, REG7 Turn-on Delay section for more information.
REG7
0x65
[1]
nFLTMSK
R/W
Regulator Fault Mask Control. Set bit to 1 enable faultinterrupts, clear bit to 0 to disable fault-interrupts.
REG7
0x65
[0]
OK
R
APCH
0x70
[7:0]
-
R/W
Reserved.
APCH
0x71
[7]
SUSCHG
R/W
Charge Suspend Control Input. Set bit to 1 to suspend
charging, clear bit to 0 to allow charging to resume.
APCH
0x71
[6]
-
R/W
Reserved.
APCH
0x71
[5:4]
TOTTIMO
R/W
Total Charge Time-out Selection. See the Charge Safety
Timers section for more information.
APCH
0x71
[3:2]
PRETIMO
R/W
Precondition Charge Time-out Selection. See the Charge
Safety Timers section for more information.
APCH
0x71
[1:0]
OVPSET
R/W
Input Over-Voltage Protection Threshold Selection. See the
Input Over-Voltage Protection section for more information.
R/W
Charge Time-out Interrupt Status. Set this bit with
TIMRPRE[ ] and/or TIMRTOT[ ] to 1 to generate an interrupt
when charge safety timers expire, read this bit to get charge
time-out interrupt status. See the Charge Safety Timers
section for more information.
R/W
Battery Temperature Interrupt Status. Set this bit with
TEMPIN[ ] and/or TEMPOUT[ ] to 1 to generate an interrupt
when a battery temperature event occurs, read this bit to get
the battery temperature interrupt status. See the Battery
Temperature Monitoring section for more information.
R/W
Input Voltage Interrupt Status. Set this bit with INCON[ ] and/or
INDIS[ ] to generate an interrupt when UVLO or OVP condition
occurs, read this bit to get the input voltage interrupt status.
See the Charge Current Programming section for more
information.
Charge State Interrupt Status. Set this bit with
CHGEOCIN[ ] and/or CHGEOCOUT[ ] to 1 to generate an
interrupt when the state machine gets in or out of EOC state,
read this bit to get the charger state interrupt status. See the
State Machine Interrupts section for more information.
APCH
APCH
APCH
0x78
0x78
0x78
[7]
[6]
[5]
TIMRSTAT1
TEMPSTAT1
INSTAT
APCH
0x78
[4]
CHGSTAT1
R/W
APCH
0x78
[3]
TIMRDAT1
R
Regulator Power-OK Status. Value is 1 when output voltage
exceeds the power-OK threshold, value is 0 otherwise.
Charge Timer Status. Value is 1 when precondition time-out or
total charge time-out occurs. Value is 0 in other case.
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ACT8938
®
Rev 3, 23-Dec-11
REGISTER AND BIT DESCRIPTIONS CONT’D
OUTPUT ADDRESS
BIT
NAME
ACCESS
DESCRIPTION
APCH
0x78
[2]
TEMPDAT1
R
Temperature Status. Value is 0 when battery temperature is
outside of valid range. Value is 1 when battery temperature
is inside of valid range.
APCH
0x78
[1]
INDAT
R
Input Voltage Status. Value is 1 when a valid input at
CHGIN is present. Value is 0 when a valid input at CHGIN
is not present.
APCH
0x78
[0]
CHGDAT1
R
Charge State Machine Status. Value is 1 indicates the
charger state machine is in EOC state, value is 0 indicates
the charger state machine is in other states.
APCH
0x79
[7]
TIMRTOT
R/W
Total Charge Time-out Interrupt Control. Set both this bit
and TIMRSTAT[ ] to 1 to generate an interrupt when a total
charge time-out occurs. See the Charge Safety Timers
section for more information.
APCH
0x79
[6]
TEMPIN
R/W
Battery Temperature Interrupt Control. Set both this bit and
TEMPSTAT[ ] to 1 to generate an interrupt when the battery
temperature goes into the valid range. See the Battery
Temperature Monitoring section for more information.
R/W
Input Voltage Interrupt Control. Set both this bit and
INSTAT[ ] to 1 to generate an interrupt when CHGIN input
voltage goes into the valid range. See the Charge Current
Programming section for more information.
R/W
Charge State Interrupt Control. Set both this bit and
CHGSTAT[ ] to 1 to generate an interrupt when the state
machine goes into the EOC state. See the State Machine
Interrupts section for more information.
APCH
APCH
0x79
0x79
[5]
[4]
INCON
CHGEOCIN
APCH
0x79
[3]
TIMRPRE
R/W
PRECHARGE Time-out Interrupt Control. Set both this bit
and TIMRSTAT[ ] to 1 to generate an interrupt when a
PRECHARGE time-out occurs. See the Charge Safety
Timers section for more information.
APCH
0x79
[2]
TEMPOUT
R/W
Battery Temperature Interrupt Control. Set both this bit and
TEMPSTAT[ ] to 1 to generate an interrupt when the battery
temperature goes out of the valid range. See the Battery
Temperature Monitoring section for more information.
R/W
Input Voltage Interrupt Control. Set both this bit and
INSTAT[ ] to 1 to generate an interrupt when CHGIN input
voltage goes out of the valid range. See the Charge Current
Programming section for more information.
Charge State Interrupt Control. Set both this bit and
CHGSTAT[ ] to 1 to generate an interrupt when the state
machines jumps out of the EOC state. See the State
Machine Interrupts section for more information.
APCH
0x79
[1]
INDIS
APCH
0x79
[0]
CHGEOCOUT
R/W
APCH
0x7A
[7:6]
-
R
Reserved.
APCH
0x7A
[5:4]
CSTATE
R
Charge State. Values indicate the current charging state.
See the State Machine Interrupts section for more
information.
APCH
0x7A
[3:2]
-
R
Reserved.
APCH
0x7A
[1]
ACINSTAT
R
ACIN Status. Indicates the state of the ACIN input, typically
in order to identify the type of input supply connected. Value
is 1 when ACIN is above the 1.2V precision threshold, value
is 0 when ACIN is below this threshold.
APCH
0x7A
[0]
-
R
Reserved.
: Valid only when CHGIN UVLO Threshold<VCHGIN<CHGIN OVP Threshold.
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ACT8938
®
Rev 3, 23-Dec-11
SYSTEM CONTROL ELECTRICAL CHARACTERISTICS
(VVSYS = 3.6V, TA = 25°C, unless otherwise specified.)
PARAMETER
TEST CONDITIONS
Input Voltage Range
MIN
TYP
2.7
UVLO Threshold Voltage
VVSYS Rising
UVLO Hysteresis
VVSYS Falling
200
REG1 Enabled. REG2, REG3, REG4,
REG5, REG6 and REG7 Disabled
150
REG1, REG2, REG3, REG4 and REG5
Enabled. REG6 and REG7 Disabled
350
REG1, REG2, REG3, REG4, REG5,
REG6 and REG7 Enabled
420
Supply Current
Shutdown Supply Current
All Regulators Disabled
Oscillator Frequency
Logic High Input Voltage
2.2
1.8
2.45
MAX
UNIT
5.5
V
2.65
V
mV
µA
8
18
µA
2
2.2
MHz
1.4
1
V
Logic Low Input Voltage
Leakage Current
VnIRQ = VnRSTO = 4.2V
LBI Threshold Voltage
VBAT Falling
LBI Hysteresis Threshold
VBAT Rising
Low Level Output Voltage
2
1.2
Temperature rising
Thermal Shutdown Hysteresis
V
1
µA
1.31
V
200
ISINK = 5mA
nRSTO Delay
Thermal Shutdown Temperature
1.03
0.4
mV
0.35
V
65
ms
160
°C
20
°C
: PWRHLD, nHIB, VSEL are logic inputs.
2: nLBO, nPBSTAT, nIRQ, nRSTO are open drain outputs.
3: Typical value shown. Actual value may vary from 56.3ms to 72.8ms.
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ACT8938
®
Rev 3, 23-Dec-11
STEP-DOWN DC/DC ELECTRICAL CHARACTERISTICS
(VVP1 = VVP2 = VVP3 = 3.6V, TA = 25°C, unless otherwise specified.)
PARAMETER
CONDITIONS
Operating Voltage Range
MIN
TYP
2.7
5.5
V
2.7
V
Input Voltage Rising
UVLO Hysteresis
Input Voltage Falling
100
Quiescent Supply Current
Regulator Enabled
65
90
µA
Shutdown Current
VVP = 5.5V, Regulator Disabled
0
1
µA
mV
VOUT ≥ 1.2V, IOUT = 10mA
-1%
VNOM
1%
VOUT < 1.2V, IOUT = 10mA
-2%
VNOM
2%
Line Regulation
VVP = Max(VNOM1 +1, 3.2V) to 5.5V
Load Regulation
IOUT = 10mA to IMAX
Power Good Threshold
Power Good Hysteresis
Oscillator Frequency
2.6
UNIT
UVLO Threshold
Output Voltage Accuracy
2.5
MAX
V
0.15
%/V
0.0017
%/mA
VOUT Rising
93
%VNOM
VOUT Falling
2
%VNOM
2
VOUT ≥ 20% of VNOM
1.8
VOUT = 0V
2
2.2
MHz
500
kHz
Soft-Start Period
400
µs
Minimum On-Time
75
ns
REG1
Maximum Output Current
1.15
Current Limit
1.5
A
1.8
2.1
A
PMOS On-Resistance
ISW1 = -100mA
0.16
Ω
NMOS On-Resistance
ISW1 = 100mA
0.16
Ω
SW1 Leakage Current
VVP1 = 5.5V, VSW1 = 0 or 5.5V
1
µA
REG2
Maximum Output Current
1.15
Current Limit
1.5
PMOS On-Resistance
A
1.8
ISW2 = -100mA
0.16
NMOS On-Resistance
ISW2 = 100mA
0.16
SW2 Leakage Current
VVP2 = 5.5V, VSW2 = 0 or 5.5V
2.1
A
Ω
Ω
1
µA
REG3
Maximum Output Current
1.3
Current Limit
1.7
A
2.1
2.5
A
PMOS On-Resistance
ISW3 = -100mA
0.16
Ω
NMOS On-Resistance
ISW3 = 100mA
0.16
Ω
SW3 Leakage Current
VVP3 = 5.5V, VSW3 = 0 or 5.5V
0
1
µA
: VNOM refers to the nominal output voltage level for VOUT as defined by the Ordering Information section.
2: IMAX Maximum Output Current.
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ACT8938
®
Rev 3, 23-Dec-11
LOW-NOISE LDO ELECTRICAL CHARACTERISTICS
(VINL = 3.6V, COUT4 = COUT5 = 1.5µF, COUT6 = COUT7 = 3.3µF, LOWIQ[ ] = [0], TA = 25°C, unless otherwise specified.)
PARAMETER
TEST CONDITIONS
Operating Voltage Range
Output Voltage Accuracy
Line Regulation
Load Regulation
Power Supply Rejection Ratio
Supply Current per Output
MIN
TYP
2.5
MAX
UNIT
5.5
V
VOUT ≥ 1.2V, TA = 25°C, IOUT = 10mA
-1%
VNOM
2%
VOUT < 1.2V, TA = 25°C, IOUT = 10mA
-2%
VNOM
4%
VINL = Max(VOUT + 0.5V, 3.6V) to 5.5V
LOWIQ[ ] = [0]
0.05
VINL = Max(VOUT + 0.5V, 3.6V) to 5.5V
LOWIQ[ ] = [1]
0.5
IOUT = 1mA to IMAX2
0.08
V
mV/V
V/A
f = 1kHz, IOUT = 20mA, VOUT =1.2V
75
f = 10kHz, IOUT = 20mA, VOUT =1.2V
65
Regulator Enabled, LOWIQ[ ] = [0]
37
60
Regulator Enabled, LOWIQ[ ] = [1]
31
52
Regulator Disabled
0
1
dB
µA
Soft-Start Period
VOUT = 2.9V
140
µs
Power Good Threshold
VOUT Rising
89
%
Power Good Hysteresis
VOUT Falling
3
%
Output Noise
IOUT = 20mA, f = 10Hz to 100kHz, VOUT =
1.2V
50
µVRMS
Discharge Resistance
LDO Disabled, DIS[ ] = 1
1.5
kΩ
IOUT = 80mA, VOUT > 3.1V
90
REG4
Dropout Voltage
Maximum Output Current
Current Limit
VOUT = 95% of regulation voltage
Stable COUT4 Range
180
mV
150
mA
200
mA
1.5
20
µF
REG5
Dropout Voltage
IOUT = 80mA, VOUT > 3.1V
Maximum Output Current
Current Limit
140
280
VOUT = 95% of regulation voltage
Stable COUT5 Range
mV
mA
150
200
mA
1.5
20
µF
180
mV
REG6
Dropout Voltage
IOUT = 160mA, VOUT > 3.1V
Maximum Output Current
Current Limit
VOUT = 95% of regulation voltage
Stable COUT6 Range
90
320
mA
400
mA
3.3
20
µF
280
mV
REG7
Dropout Voltage
IOUT = 160mA, VOUT > 3.1V
Maximum Output Current
Current Limit
140
320
VOUT = 95% of regulation voltage
Stable COUT7 Range
mA
400
mA
3.3
20
µF
: VNOM refers to the nominal output voltage level for VOUT as defined by the Ordering Information section.
2: IMAX Maximum Output Current.
3: Dropout Voltage is defined as the differential voltage between input and output when the output voltage drops 100mV below the
regulation voltage (for 3.1V output voltage or higher).
: LDO current limit is defined as the output current at which the output voltage drops to 95% of the respective regulation voltage.
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Copyright © 2011 Active-Semi, Inc.
ACT8938
®
Rev 3, 23-Dec-11
ActivePathTM CHARGER ELECTRICAL CHARACTERISTICS
(VCHGIN = 5.0V, TA = 25°C, unless otherwise specified.)
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNIT
6.0
V
3.9
V
ActivePath
CHGIN Operating Voltage Range
4.35
CHGIN UVLO Threshold
CHGIN Voltage Rising
CHGIN UVLO Hysteresis
CHGIN Voltage Falling
CHGIN OVP Threshold
CHGIN Voltage Rising
CHGIN OVP Hysteresis
CHGIN Voltage Falling
0.4
VCHGIN < VUVLO
35
70
µA
VCHGIN < VBAT + 50mV, VCHGIN > VUVLO
100
200
µA
VCHGIN > VBAT + 150mV, VCHGIN > VUVLO
Charger disabled, IVSYS = 0mA
1.3
2.0
mA
IVSYS = 100mA
0.3
Ω
A
CHGIN Supply Current
CHGIN to VSYS On-Resistance
CHGIN to VSYS Current Limit
3.1
3.5
0.5
6.0
6.6
V
7.2
V
V
ACIN = VSYS
1.5
2
ACIN = GA, CHGLEV = GA
80
90
100
ACIN = GA, CHGLEV = VSYS
400
450
500
IVSYS = 10mA
4.45
4.6
4.8
V
4
8
12
mA
1
µA
mA
VSYS REGULATION
VSYS Regulated Voltage
nSTAT OUTPUT
nSTAT Sink current
VnSTAT = 2V
nSTAT Leakage Current
VnSTAT = 4.2V
ACIN AND CHGLEV INPUTS
CHGLEV Logic High Input Voltage
1.4
V
CHGLEV Logic Low Input Voltage
CHGLEV Leakage Current
VCHGLEV = 4.2V
ACIN Voltage Thresholds
ACIN voltage rising
ACIN Hysteresis voltage threshold
ACIN voltage falling
ACIN Leakage Current
VACIN = 4.2V
1.03
1.2
0.4
V
1
µA
1.31
V
200
mV
1
µA
TH INPUT
TH Pull-Up Current
VCHGIN > VBAT + 100mV, Hysteresis = 50mV
91
102
110
µA
VTH Upper Temperature Voltage
Threshold (VTHH)
Hot Detect NTC Thermistor
2.44
2.51
2.58
V
VTH Lower Temperature Voltage
Threshold (VTHL)
Cold Detect NTC Thermistor
0.47
0.50
0.53
V
VTH Hysteresis
Upper and Lower Thresholds
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- 18 Active-Semi Proprietary―For Authorized Recipients and Customers
ActivePMUTM and ActivePathTM are trademarks of Active-Semi.
I2CTM is a trademark of NXP.
30
mV
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Copyright © 2011 Active-Semi, Inc.
ACT8938
®
Rev 3, 23-Dec-11
ActivePathTM CHARGER ELECTRICAL CHARACTERISTICS CONT’D
(VCHGIN = 5.0V, TA = 25°C, unless otherwise specified.)
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX UNIT
CHARGER
BAT Reverse Leakage Current
VCHGIN = 0V, VBAT = 4.2V, IVSYS = 0mA
BAT to VSYS On-Resistance
ISET Pin Voltage
Charge Termination Voltage
VTERM
Charge Current
Precondition Charge Current
µA
70
mΩ
Fast Charge
1.2
Precondition
0.13
V
TA = -20°C to 70°C
4.179
4.2
4.221
TA = -40°C to 85°C
4.170
4.2
4.230
ACIN = VSYS, CHGLEV = VSYS
-10%
ICHG1
+10%
ACIN = VSYS, CHGLEV = GA
-10%
ICHG/5
+10%
ACIN = GA, CHGLEV = VSYS
400
450
500
ACIN = GA, CHGLEV = GA
80
90
100
VBAT = 3.8V
RISET = 6.8K
VBAT = 2.7V
RISET = 6.8K
ACIN = VSYS, CHGLEV = VSYS
10% ICHG
ACIN = VSYS, CHGLEV = GA
10% ICHG
ACIN = GA, CHGLEV = VSYS
45
ACIN = GA, CHGLEV = GA
45
Precondition Threshold Voltage
VBAT Voltage Rising
Precondition Threshold
Hysteresis
VBAT Voltage Falling
END-OF-CHARGE Current
Threshold
8
VBAT = 4.15V
2.75
2.85
10% ICHG
ACIN = VSYS, CHGLEV = GA
10% ICHG
ACIN = GA, CHGLEV = VSYS
45
ACIN = GA, CHGLEV = GA
45
3.0
205
V
mV
mA
Charge Restart Threshold
VTERM - VBAT, VBAT Falling
Precondition Safety Timer
PRETIMO[ ] = 10
80
min
Total Safety Timer
TOTTIMO[ ] = 10
5
hr
100
°C
Thermal Regulation Threshold
190
mA
mA
150
ACIN = VSYS, CHGLEV = VSYS
V
220
mV
: RISET (kΩ) = 2336 × (1V/ICHG (mA)) - 0.205
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Copyright © 2011 Active-Semi, Inc.
ACT8938
®
Rev 3, 23-Dec-11
TYPICAL PERFORMANCE CHARACTERISTICS
(VVSYS = 3.6V, TA = 25°C, unless otherwise specified.)
Frequency vs. Temperature
VREF vs. Temperature
0
-0.42
2
Frequency (%)
VREF (%)
0.42
2.5
-20
0
20
40
60
80
100
1.5
1
0.5
0
-0.5
Typical VREF=1.2V
-0.84
-40
ACT8938-002
ACT8938-001
0.84
Typical Oscillator Frequency=2MHz
-1
-40
120
-20
0
20
40
60
Temperature (°C)
Temperature (°C)
nPBIN Startup Sequence
PWRHLD Startup Sequence
ACT8938-004
ACT8938-003
CH1
80 85
CH1
CH2
CH3
CH2
CH4
CH5
CH6
CH3
CH1: VnPBIN, 5V/div
CH2: VOUT2, 2V/div
CH3: VOUT4, 2V/div
CH4: VOUT3, 2V/div
CH5: VOUT1, 2V/div
CH6: VOUT5, 2V/div
TIME: 2ms/div
CH1: VnPBIN, 2V/div
CH2: VPWRHLD, 2V/div
CH3: VOUT1, 2V/div
FRC_ON1[ ] = 0
TIME: 100ms/div
PWRHLD Startup Sequence
PWRHLD Startup Sequence
CH1
CH2
CH2
CH3
CH3
CH1: VnPBIN, 2V/div
CH2: VOUT1, 2V/div
CH3: VPWRHLD, 2V/div
FRC_ON1[ ] = 0
TIME: 100ms/div
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ACT8938-006
ACT8938-005
CH1
CH1: VnPBIN, 2V/div
CH2: VPWRHLD, 2V/div
CH3: VOUT1, 2V/div
FRC_ON1[ ] = 1
TIME: 100ms/div
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Copyright © 2011 Active-Semi, Inc.
ACT8938
®
Rev 3, 23-Dec-11
TYPICAL PERFORMANCE CHARACTERISTICS
(VVSYS = 3.6V, TA = 25°C, unless otherwise specified.)
nHIB Sequence
nHIB Sequence
ACT8938-008
ACT8938-007
CH1
CH1
CH2
CH2
CH3
CH3
CH4
CH5
CH4
CH1: VnPBIN, 2V/div
CH2: VnHIB, 2V/div
CH3: VOUT2, 2V/div
CH4: VnRSTO, 2V/div
TIME: 20ms/div
CH1: VnHIB, 2V/div
CH2: VOUT2, 2V/div
CH3: VOUT4, 1.97V/div
CH4: VOUT3, 1V/div
CH5: VOUT5, 2V/div
TIME: 2ms/div
nHIB Sequence
ACT8938-009
CH1
CH2
CH3
CH4
CH5
CH6
CH1: VnHIB, 5V/div
CH2: VOUT2, 2V/div
CH3: VOUT4, 2V/div
CH4: VOUT3, 2V/div
CH5: VOUT1, 2V/div
CH6: VOUT5, 5V/div
TIME: 20ms/div
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Copyright © 2011 Active-Semi, Inc.
ACT8938
®
Rev 3, 23-Dec-11
TYPICAL PERFORMANCE CHARACTERISTICS CONT’D
(TA = 25°C, unless otherwise specified.)
Push-Button Response (First Power-Up)
Manual Reset Response
ACT8938-011
ACT8938-010
CH1
CH1
CH2
CH2
CH3
CH3
CH4
CH1: VnPBIN, 2V/div
CH2: VnHIB, 2V/div
CH3: VnPBSTAT, 2V/div
CH4: VnRSTO, 2V/div
TIME: 20ms/div
CH1: VnPBIN, 2V/div
CH2: VnPBSTAT, 2V/div
CH3:VnRSTO , 2V/div
TIME: 30ms/div
nPBIN Resistor = 50kΩ
REG2 Efficiency vs. Output Current
REG1 Efficiency vs. Output Current
VIN = 3.6V
VIN = 4.2V
60
VIN = 5.0V
80
VIN = 4.2V
Efficiency (%)
Efficiency (%)
VIN = 5.0V
VOUT = 3.3V
40
VIN = 3.6V
ACT8938-013
VOUT = 1.8V
80
100
ACT8938-012
100
nPBIN Resistor = 0Ω
60
40
20
20
0
0
1
10
100
1000
1
10
Output Current (mA)
100
1000
Output Current (mA)
REG3 Efficiency vs. Output Current
VOUT = 1.2V
80
Efficiency (%)
ACT8938-014
100
VIN = 5.0V
VIN = 3.6V
VIN = 4.2V
60
40
20
0
10
1
100
1000
Output Current (mA)
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- 22 Active-Semi Proprietary―For Authorized Recipients and Customers
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Copyright © 2011 Active-Semi, Inc.
ACT8938
®
Rev 3, 23-Dec-11
TYPICAL PERFORMANCE CHARACTERISTICS CONT’D
(TA = 25°C, unless otherwise specified.)
REG2 Output Voltage vs. Temperature
REG1 Output Voltage vs. Temperature
Output Voltage (V)
1.809
1.803
1.797
1.791
1.785
-40
-20
0
20
40
60
80
100
3.310
VOUT2 = 3.3V
ILOAD = 100mA
3.306
Output Voltage (V)
VOUT1 = 1.8V
ILOAD = 100mA
3.302
3.298
3.294
3.290
-40
120
-20
0
20
40
60
80
100
120
Temperature (°C)
Temperature (°C)
REG1, 2, 3 MOSFET Resistance
REG3 Output Voltage vs. Temperature
1.202
1.198
ILOAD = 100mA
300
250
RDSON (mΩ)
1.206
ACT8938-018
350
ACT8938-017
1.210 V
OUT3 = 1.2V
ILOAD = 100mA
Output Voltage (V)
ACT8938-016
ACT8938-015
1.815
200
PMOS
NMOS
150
100
1.194
1.190
-40
50
0
-20
0
20
40
60
80
100
120
Temperature (°C)
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- 23 Active-Semi Proprietary―For Authorized Recipients and Customers
ActivePMUTM and ActivePathTM are trademarks of Active-Semi.
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3.0
3.5
4.0
4.5
5.0
5.5
Input Voltage (V)
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Copyright © 2011 Active-Semi, Inc.
ACT8938
®
Rev 3, 23-Dec-11
TYPICAL PERFORMANCE CHARACTERISTICS CONT’D
(TA = 25°C, unless otherwise specified.)
Output Voltage vs. Output Current
Output Voltage (V)
1.860
1.840
REG4
1.800
1.780
1.760
1.740
3.380
3.360
3.340
3.320
3.300
REG5
3.280
3.260
3.240
3.220
1.720
1.700
ACT8938-020
ACT8938-019
1.880
1.820
Output Voltage vs. Output Current
3.400
Output Voltage (V)
1.900
3.200
0
20
40
60
80
100
120
140
0
160
20
40
Output Current (mA)
Output Voltage vs. Output Current
Output Voltage (V)
120
140
160
3.340
REG6
3.300
3.280
3.260
3.240
ACT8938-022
ACT8938-021
3.360
3.390
3.350
3.310
REG7
3.270
3.230
3.190
3.220
3.200
0
50
100
150
200
250
300
350
400
3.150
450
0
50
Output Current (mA)
Dropout Voltage vs. Output Current
80
60
40
60
80
100
120
350
400
450
140
REG5
150
100
50
VIN = 3.3V
0
VIN = 3.3V
40
300
200
20
20
250
250
Dropout Voltage (mV)
REG4
0
200
ACT8938-024
ACT8938-023
120
0
150
Dropout Voltage vs. Output Current
140
100
100
Output Current (mA)
160
Dropout Voltage (mV)
100
Output Voltage vs. Output Current
3.380
3.320
80
3.430
Output Voltage (V)
3.400
60
Output Current (mA)
160
Output Current (mA)
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- 24 Active-Semi Proprietary―For Authorized Recipients and Customers
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0
20
40
60
80
100
120
140
160
Output Current (mA)
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Copyright © 2011 Active-Semi, Inc.
ACT8938
®
Rev 3, 23-Dec-11
TYPICAL PERFORMANCE CHARACTERISTICS CONT’D
(TA = 25°C, unless otherwise specified.)
Dropout Voltage vs. Output Current
Dropout Voltage vs. Output Current
REG6
150
100
50
350
300
Dropout Voltage (mV)
Dropout Voltage (mV)
200
VIN = 3.3V
0
0
50
100
150
200
250 300 350 400
250
REG7
200
150
100
50
VIN = 3.3V
0
450
0
50
Output Current (mA)
Output Voltage vs. Temperature
200
250 300 350 400
450
3.00
ESR (Ω)
2.50
REG4
1.50
ACT8938-028
1
ACT8938-027
Output Voltage (V)
150
Region of Stable COUT ESR vs. Output Current
REG5, REG6, REG7
2.00
100
Output Current (mA)
4.00
3.50
ACT8938-026
ACT8938-025
250
0.1
Stable ESR
1.00
0.50
0.01
0
-40
-20
0
20
40
60
80
100
120
0
50
100
150
200
250
300
340
Output Current (mA)
Temperature (°C)
LDO Output Voltage Noise
ACT8938-029
CH1
CH1: VOUTx, 200µV/div (AC COUPLED)
TIME: 200ms/div
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- 25 Active-Semi Proprietary―For Authorized Recipients and Customers
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Copyright © 2011 Active-Semi, Inc.
ACT8938
®
Rev 3, 23-Dec-11
TYPICAL PERFORMANCE CHARACTERISTICS CONT’D
(TA = 25°C, unless otherwise specified.)
VSYS Voltage vs. CHGIN Voltage
VSYS Voltage vs. VSYS Current
4.0
ACIN/CHGLEV = 01
ACIN/CHGLEV = 11
3.0
2.0
5.0
VSYS Voltage (V)
VSYS Voltage (V)
5.0
5.2
ACT8938-031
ACT8938-030
6.0
4.8
VVSYS = 4.6V
4.6
4.4
4.2
1.0
4.0
0
0
500
1000
1500
2000
2
0
2500
4
70
60
50
40
30
VCHGIN = 5V
ACIN = 0
CHGLEV = 0
90mA USB
0
0.0
Charger Current (mA)
1.5
2.0
2.5
3.0
3.5
4.0
350
300
250
200
150
VBAT Falling
VBAT Rising
100
0
0.0
4.5
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
Battery Voltage (V)
Battery Voltage (V)
Charger Current vs. Battery Voltage
DCCC and Battery Supplement Modes
RISET = 2.4kΩ
VCHGIN = 5V
ACIN/CHGLEV = 11
800
4.5
ACT8938-035
1000
1.0
CHGLEV = 1
400 450mA USB
50
ACT8938-034
1200
0.5
VCHGIN = 5V
450 ACIN = 0
Charger Current (mA)
Charger Current (mA)
80
500
ACT8938-033
ACT8938-032
90
VBAT Falling
VBAT Rising
10
Charger Current vs. Battery Voltage
Charger Current vs. Battery Voltage
100
10
8
CHGIN Voltage (V)
VSYS Current (mA)
20
6
CH4
CH3
600
CH2
VBAT = 3.5V
VVSYS = 4.6V
IVSYS = 0-1.8A
ICHARGE = 1000mA
VCHGIN = 5.1V-3A
400
VBAT Falling
VBAT Rising
200
CH1
0
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
Battery Voltage (V)
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I2CTM is a trademark of NXP.
CH1: IVSYS, 1.00A/div
CH2: IBAT, 1.00A/div
CH3: VBAT, 1.00V/div
CH4: VVSYS, 1V/div
TIME: 200ms/div
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Copyright © 2011 Active-Semi, Inc.
ACT8938
®
Rev 3, 23-Dec-11
TYPICAL PERFORMANCE CHARACTERISTICS CONT’D
(TA = 25°C, unless otherwise specified.)
VAC Applied
VAC Removed
CH3
ACT8938-037
ACT8938-036
CH4
CH4
CH3
CH2
CH2
CH1
CH1
CH1: IBAT, 400mA/div
CH2: VBAT, 1V/div
CH3: VVSYS, 2V/div
CH4: VCHGIN, 5V/div
TIME: 40ms/div
VCHGIN = 5V
VBAT = 3.5V
RVSYS = 100Ω
ACIN/CHGLEV = 01
CH1: IBAT, 200mA/div
CH2: VVSYS, 2V/div
CH3: VBAT, 1V/div
CH4: VCHGIN, 5V/div
TIME: 40ms/div
VAC Applied
VAC Removed
CH3
ACT8938-039
ACT8938-038
CH4
VCHGIN = 5V
VBAT = 3.5V
RVSYS = 100Ω
ACIN/CHGLEV = 01
CH4
CH3
CH2
CH2
CH1
CH1
CH1: IBAT, 1A/div
CH2: VBAT, 2V/div
CH3: VVSYS, 2V/div
CH4: VCHGIN, 5V/div
TIME: 40ms/div
VCHGIN = 5V
VBAT = 3.97V
RVSYS = 47Ω
ACIN/CHGLEV = 11
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CH1: IBAT, 1A/div
CH2: VVSYS, 2V/div
CH3: VBAT, 2V/div
CH4: VCHGIN, 5V/div
TIME: 40ms/div
VCHGIN = 5V
VBAT = 3.97V
RVSYS = 47Ω
ACIN/CHGLEV = 11
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Copyright © 2011 Active-Semi, Inc.
ACT8938
®
Rev 3, 23-Dec-11
SYSTEM CONTROL INFORMATION
Interfacing with the Marvell Aspen
The ACT8938 is optimized for use in applications
using the Marvell Aspen processors, supporting
both the power domains as well as the signal
interface for these processors.
While the ACT8938 supports many possible
configurations for powering these processors, one
of the most common configurations is detailed in
this datasheet. In general, this document refers to
the ACT8938 pin names and functions. However, in
cases where the description of interconnections
between these devices benefits by doing so, both
the ACT8938 pin names and the Marvell Aspen
processors pin names are provided. When this is
done, the Aspen pin names are located after the
ACT8938 pin names, and are italicized and located
inside parentheses. For example, VSEL
(DVS_GPIO) refers to the logic signal applied to the
ACT8938's VSEL input, identifying that it is driven
from the Aspen's DVS_GPIO output. Likewise,
OUT2 (VDD_IO ) refers to ACT8938's OUT2 pin,
identifying that it is connected to the Aspen's
VDD_IO power domain.
Table 2:
ACT8938 and Marvell Aspen Power Domains
POWER DOMAIN
ACT8938 CHANNEL
TYPE
DEFAULT VOLTAGE
CURRENT CAPABILITY
VDD_M
REG1
DC/DC
1.8V/1.8V
1150mA
VDD_IO
REG2
DC/DC
3.3V/3.3V
1150mA
VDD_Core
REG3
DC/DC
1.1V/1.0V
1300mA
REG4
LDO
1.8V
150mA
AVDD_USB
REG5
LDO
3.3V
150mA
TBD
REG6
LDO
3.3V
320mA
TBD
REG7
LDO
3.3V
320mA
AVDD_OSC
AVDD_PLL
Table 3:
ACT8938 and Marvell Aspen Power Modes
POWER
MODE
CONTROL STATE
POWER DOMAIN STATE
QUIESCENT
CURRENT
ALL ON
PWRHLD is asserted, nHIB is de-asserted,
REG6 and REG7 are enabled by I2C
REG1, REG2, REG3, REG4, REG5,
REG6 and REG7 are all on
420µA
NORMAL
PWRHLD is asserted, nHIB is de-asserted,
REG6 and REG7 are disabled by I2C
REG1, REG2, REG3, REG4 and
REG5 are on. REG6 and REG7 are off
350µA
Hibernate
PWRHLD is asserted, nHIB is asserted,
FRC_ON1[ ] is 1, REG6 and REG7 are
disabled by I2C
REG1 is on. REG2,REG3,REG4,REG5,
REG6 and REG7 are off
150µA
ALL OFF
PWRHLD is de-asserted, nHIB is
asserted, REG6 and REG7 are disabled by
I 2C
REG1, REG2, REG3, REG4, REG5,
REG6 and REG7 are all off
<18µA
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ACT8938
®
Rev 3, 23-Dec-11
Table 4:
ACT8938 Signal Interface with Marvell Aspen
ACT8938
DIRECTION
MARVELL ASPEN
SCL
PWR_SCL
SDA
PWR_SDA
VSEL
DVS_GPIO
nRSTO
RESET_IN_N
nIRQ
EXT_WAKEUP
nPBSTAT
EXT_WAKEUP
PWRHLD
GPIO
nHIB
GPIO
1: Optional connection for DVS control.
2, : External wake up/interrupt signal used to wake up the processor from system idle mode.
, : Optional connection for shut down control.
Table 5:
Control Pins
PIN NAME
OUTPUT
nPBIN
REG1, REG2, REG3, REG4, REG5
PWRHLD
REG1
nHIB
REG2, REG3, REG4, REG5
Control Signals
Manual Reset Function
Enable Inputs
The ACT8938 features a variety of control inputs,
which are used to enable and disable outputs
depending upon the desired mode of operation.
nHIB, PWRHLD are logic inputs, while nPBIN is a
unique, multi-function input. Refer to Table 5 for a
description of which channels are controlled by
each input.
nPBIN Multi-Function Input
ACT8938 features the nPBIN multi-function pin,
which combines system enable/disable control with
a hardware reset function. Select either of the two
pin functions by asserting this pin, either through a
direct connection to GA, or through a 50kΩ resistor
to GA, as shown in Figure 2.
Figure 2:
The second major function of the nPBIN input is to
provide a manual-reset input for the processor. To
manually-reset the processor, drive nPBIN directly
to GA through a low impedance (less than 2.5kΩ).
When this occurs, nRSTO immediately asserts low,
then remains asserted low until the nPBIN input is
de-asserted and the reset time-out period expires.
nPBSTAT Output
nPBSTAT is an open-drain output that reflects the
state of the nPBIN input; nPBSTAT is asserted low
whenever nPBIN is asserted, and is high-Z
otherwise. This output is typically used as an
interrupt signal to the processor, to initiate a
software-programmable routine such as operating
mode selection or to open a menu. Connect
nPBSTAT to an appropriate supply voltage
(typically OUT2) through a 10kΩ or greater resistor.
nRSTO Output
nPBIN Input
nRSTO is an open-drain output which asserts low
upon startup or when manual reset is asserted via
the nPBIN input. When asserted on startup, nRSTO
remains low until reset time-out period expires after
OUT2 reaches its power-OK threshold. When
asserted due to manual-reset, nRSTO immediately
asserts low, then remains asserted low until the
nPBIN input is de-asserted and the reset time-out
period expires.
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ACT8938
®
Rev 3, 23-Dec-11
Connect a 10kΩ or greater pull-up resistor from
nRSTO to an appropriate voltage supply (typically
OUT2).
nIRQ Output
nIRQ is an open-drain output that asserts low any
time an interrupt is generated. Connect a 10kΩ or
greater pull-up resistor from nIRQ to an appropriate
voltage supply. nIRQ is typically used to drive the
interrupt input of the system processor.
Many of the ACT8938's functions support interruptgeneration as a result of various conditions. These
are typically masked by default, but may be
unmasked via the I2C interface. For more
information about the available fault conditions,
refer to the appropriate sections of this datasheet.
Note that under some conditions a false interrupt
may be generated upon initial startup. For this
reason, it is recommended that the interrupt service
routine check and validate nSYSLEVMSK[-] and
nFLTMSK[-] bits before processing an interrupt
generated by these bits. These interrupts may be
validated by nSYSSTAT[-], OK[-] bits.
Push-Button Control
The ACT8938 is designed to initiate a system
enable sequence when the nPBIN multi-function
input is asserted. Once this occurs, a power-on
sequence commences, as described below. The
power-on sequence must complete and the
microprocessor must take control (by asserting
PWRHLD and de-asserting nHIB) before nPBIN is
de-asserted. If the microprocessor is unable to
complete its power-up routine successfully before
the user releases the push-button, the ACT8938
automatically shuts the system down. This provides
protection against accidental or momentary
assertions of the push-button. If desired, longer
“push-and-hold” times can be implemented by
simply adding an additional time delay before
asserting PWRHLD and de-asserting nHIB.
Control Sequences
The ACT8938 features a variety of control
sequences that are optimized for supporting system
enable and disable, as well as Hibernate mode of
the Aspen processors.
Enable Sequence
A typical enable sequence initiates as a result of
asserting nPBIN, and begins by enabling REG2,
REG4, REG3, REG1 and REG5. When REG2
: Typical value shown,
reaches its power-OK threshold, REG4 is enabled
and nRSTO is asserted low, resetting the
microprocessor. REG3 is enabled when REG2
reaches its power-OK threshold for 2ms . REG1 is
enabled when REG2 reaches its power-OK
threshold for 4ms . REG5 is enabled when REG2
reaches its power-OK threshold for 8ms . If REG2
is above its power-OK threshold when the reset
timer expires, nRSTO is de-asserted, allowing the
microprocessor to begin its boot sequence.
During the boot sequence, the processor should
read the HBRDY[ ] bit; if the value of HBRDY[ ] is 0
then the software should proceed with a typical
enable sequence, whereas if the value of HBRDY[ ]
is 1 then the software should proceed with a “wake
from Hibernate Mode” routine. See the Hibernate
Mode Sequence section for more information.
During the boot sequence, the microprocessor must
assert PWRHLD, holding REG1, and set nHIB to a
logic high, holding REG2, REG3, REG4 and REG5
to ensure that the system remains powered after
nPBIN is released. REG6 and REG7 should be
enabled/disabled via I2C after microprocessor
completes its boot sequence.
Once the power-up routine is completed, the
system remains enabled after the push-button is
released as long as PWRHLD is asserted and nHIB
is de-asserted. If the processor does not assert
PWRHLD or de-assert nHIB to logic high before the
user releases the push-button, the boot-up
sequence is terminated and all regulators are
disabled. This provides protection against "falseenable", when the push-button is accidentally
depressed, and also ensures that the system
remains enabled only if the processor successfully
completes the boot-up sequence.
Hibernate Mode Sequence
The ACT8938 supports Hibernate mode of
operation for Aspen processor. Once a successful
power-up routine is completed, Hibernate mode
may be initiated through a variety of softwarecontrolled mechanisms. Hibernate mode is typically
initiated when the user presses the push-button
during normal operation. Pressing the push-button
asserts the nPBIN input, which asserts the
nPBSTAT output to interrupt the processor. In
response to this interrupt the processor should first
set the FRC_ON1[ ] bit to 1, and the HBRDY[ ] bit to
1. Then the processor should assert nHIB to logic
low, disabling REG2, REG3, REG4, REG5.
Waking from Hibernate mode is initiated when the
actual delay time may vary from (T-1ms) x 88% to T x 112%, where T is the typical delay time setting.
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ACT8938
®
Rev 3, 23-Dec-11
user presses the push-button again. Asserting
nPBIN enables REG2, REG3, REG4 and REG5.
Once REG2 reaches regulation, REG3 is enabled
and the nRSTO timer begins. Once the reset timer
period expires the nRSTO output is deasserted and the processor initiates a boot-up
sequence, during which it should determine the
system status by reading the HBRDY[ ] bit; if the
value of HBRDY[ ] is 0 then the software should
proceed with a typical enable sequence, whereas if
the value of HBRDY[ ] is 1 then the software should
proceed with a “wake from Hibernate Mode”
routine. To complete the wake process, the
processor should assert PWRHLD, holding REG1,
and de-assert nHIB to logic high, holding REG2,
REG3, REG4 and REG5 to ensure that the system
remains enabled after the push-button is released
then set FRC_ON1[ ] and HBRDY[ ] to 0 to
complete a full wake-up routine.
Disable Sequence
As with the enable sequence, a typical disable
sequence is initiated when the user presses the
push-button, which interrupts the processor via the
nPBSTAT output. The actual disable sequence is
completely software-controlled, but typically
involved initiating various “clean-up” processes
before finally de-assert PWRHLD and assert nHIB
to logic low, disabling all regulators and shutting the
system down. It is important that FRC_ON1[ ] is
clear to 0 prior to shutting down the system,
otherwise REG1 will remain ON.
Figure 3:
Enable Sequence
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®
ACT8938
Rev 3, 23-Dec-11
Figure 4:
Hibernate Mode Sequence
Figure 5:
Disable Sequence
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ACT8938
®
Rev 3, 23-Dec-11
FUNCTIONAL DESCRIPTION
I2C Interface
below the SYSLEV[-] voltage threshold:
The ACT8938 features an I2C interface that allows
advanced programming capability to enhance overall
system performance. To ensure compatibility with a
wide range of system processors, the I2C interface
supports clock speeds of up to 400kHz (“Fast-Mode”
operation) and uses standard I2C commands. I2C
write-byte commands are used to program the
ACT8938, and I2C read-byte commands are used to
read the ACT8938’s internal registers. The ACT8938
always 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 readoperation or a write-operation, [1011011x].
1) If nSYSMODE[-] = 1 (default case), when system
vo l ta g e
l e ve l
i n te r r u p t
is
unmasked
(nSYSLEVMSK[ ]=1) and VVSYS falls below the
programmable threshold, the ACT8938 asserts
nIRQ, providing a software “under-voltage alarm”.
The response to this interrupt is controlled by the
CPU, but will typically initiate a controlled shutdown
sequence either or alert the user that the battery is
low. In this case the interrupt is cleared when VVSYS
rises up again above the SYSLEV rising threshold
and nSYSSTAT[-] is read via I2C.
SDA is a bi-directional data line and SCL is a clock
input. The master device initiates a transaction by
issuing a START condition, defined by SDA
transitioning from high to low while SCL is high. Data
is transferred in 8-bit packets, beginning with the
MSB, and is clocked-in on the rising edge of SCL.
Each packet of data is followed by an “Acknowledge”
(ACK) bit, used to confirm that the data was
transmitted successfully.
For more information regarding the I2C 2-wire serial
interface,
go
to
the
NXP
website:
http://www.nxp.com.
Voltage Monitor and Interrupt
Programmable System Voltage Monitor
The ACT8938 features a programmable systemvoltage monitor, which monitors the voltage at VSYS
and compares it to a programmable threshold
voltage. The programmable voltage threshold is
programmed by SYSLEV[3:0], as shown in Table 6.
SYSLEV[ ] is set to 3.0V by default. There is a
200mV rising hysteresis on SYSLEV[ ] threshold
such that VVSYS needs to be 3.2V(typ) or higher in
order to power up the IC.
The nSYSSTAT[-] bit reflects the output of an
internal voltage comparator that monitors VVSYS
relative to the SYSLEV[-] voltage threshold, the
value of nSYSTAT[-] = 1 when VVSYS is lower than
the SYSLEV[-] voltage threshold, and nSYSTAT[-] =
0 when VVSYS is higher than the SYSLEV[-] voltage
threshold. Note that the SYSLEV[-] voltage threshold
is defined for falling voltages, and that the
comparator produces about 200mV of hysteresis at
VSYS. As a result, once VVSYS falls below the
SYSLEV threshold, its voltage must increase by
more than about 200mV to clear that condition.
After the IC is powered up, the ACT8938 responds in
one of two ways when the voltage at VSYS falls
2) If nSYSMODE[-] = 0, when VVSYS falls below the
programmable threshold the ACT8938 shuts down,
immediately disabling all regulators. This option is
useful for implementing a programmable “undervoltage lockout” function that forces the system off
when the battery voltage falls below the SYSLEV
threshold voltage. Since this option does not support
a controlled shutdown sequence, it is generally used
as a "fail-safe" to shut the system down when the
battery voltage is too low.
Table 6:
SYSLEV Falling Threshold
SYSLEV[3:0]
0000
0001
0010
0011
0100
0101
0110
0111
1000
1001
1010
1011
1100
1101
1110
1111
Precision Voltage Detector
The LBI input connects to one input of a precision
voltage comparator, which can be used to monitor a
system voltage such as the battery voltage. An
external resistive-divider network can be used to set
voltage monitoring thresholds, as shown in
Functional Block Diagram. The output of the
comparator is present at the nLBO open-drain
output.
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SYSLEV Falling Threshold
(Hysteresis = 200mV)
2.3
2.4
2.5
2.6
2.7
2.8
2.9
3.0
3.1
3.2
3.3
3.4
3.5
3.6
3.7
3.8
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Copyright © 2011 Active-Semi, Inc.
®
ACT8938
Rev 3, 23-Dec-11
Thermal Shutdown
The ACT8938 integrates thermal shutdown
protection circuitry to prevent damage resulting from
excessive thermal stress, as may be encountered
fault conditions. This circuitry disables all regulators if
the ACT8938 die temperature exceeds 160°C, and
prevents the regulators from being enabled until the
IC temperature drops by 20°C (typ).
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ACT8938
®
Rev 3, 23-Dec-11
STEP-DOWN DC/DC REGULATORS
General Description
The ACT8938 features three synchronous, fixedfrequency, current-mode PWM step down
converters that achieve peak efficiencies of up to
97%. REG1 and REG2 are capable of supplying up
to 1150mA of output current, while REG3 supports
up to 1300mA. These regulators operate with a
fixed frequency of 2MHz, minimizing noise in
sensitive applications and allowing the use of small
external components.
100% Duty Cycle Operation
Each regulator is capable of operating at up to
100% duty cycle. During 100% duty-cycle
operation, the high-side power MOSFET is held on
continuously, providing a direct connection from the
input to the output (through the inductor), ensuring
the lowest possible dropout voltage in battery
powered applications.
Synchronous Rectification
REG1, REG2, and REG3 each feature integrated nchannel synchronous rectifiers, maximizing
efficiency and minimizing the total solution size and
cost by eliminating the need for external rectifiers.
Soft-Start
When enabled, each output voltages tracks an
internal 400μs soft-start ramp, minimizing input
current during startup and allowing each regulator
to power up in a smooth, monotonic manner that is
independent of output load conditions.
Compensation
Each buck regulator utilizes current-mode control
and a proprietary internal compensation scheme to
simultaneously simplify external component
selection and optimize transient performance over
its full operating range. No compensation design is
required; simply follow a few simple guidelines
described below when choosing external
components.
Input Capacitor Selection
The input capacitor reduces peak currents and
noise induced upon the voltage source. A 4.7μF
ceramic capacitor is recommended for each
regulator in most applications.
Output Capacitor Selection
For most applications, 22μF ceramic output
capacitors are recommended for REG1, REG2 and
REG3.
Despite the advantages of ceramic capacitors, care
must be taken during the design process to ensure
stable operation over the full operating voltage and
temperature range. Ceramic capacitors are
available in a variety of dielectrics, each of which
exhibits different characteristics that can greatly
affect performance over their temperature and
voltage ranges.
Two of the most common dielectrics are Y5V and
X5R. Whereas Y5V dielectrics are inexpensive and
can provide high capacitance in small packages,
their capacitance varies greatly over their voltage
and temperature ranges and are not recommended
for DC/DC applications. X5R and X7R dielectrics
are more suitable for output capacitor applications,
as their characteristics are more stable over their
operating ranges, and are highly recommended.
Inductor Selection
REG1, REG2, and REG3 utilize current-mode control
and a proprietary internal compensation scheme to
simultaneously simplify external component selection
and optimize transient performance over their full
operating range. These devices were optimized for
operation with 2.2μH inductors, although inductors in
the 1.5μH to 3.3μH range can be used. Choose an
inductor with a low DC-resistance, and avoid inductor
saturation by choosing inductors with DC ratings that
exceed the maximum output current by at least 30%.
Configuration Options
Output Voltage Programming
By default, each regulator powers up and regulates
to its default output voltage. Output voltage is
selectable by setting VSEL pin that when VSEL is
low, output voltage is programmed by VSET1[-]
bits, and when VSEL is high, output voltage is
programmed by VSET2[-] bits. However, once the
system is enabled, each regulator's output voltage
may be independently programmed to a different
value, typically in order to minimize the power
consumption of the microprocessor during some
operating modes. Program the output voltages via
the I2C serial interface by writing to the regulator's
VSET1[-] register if VSEL is low or VSET2[-]
register if VSEL is high as shown in Table 7.
Enable / Disable Control
During normal operation, each buck may be
enabled or disabled via the I2C interface by writing
to that regulator's ON[ ] bit. The regulator accept
rising or falling edge of ON[ ] bit as on/off signal. To
enable the regulator, clear ON[ ] to 0 first then set to
1. To disable the regulator, set ON[ ] to 1 first then
clear it to 0.
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ACT8938
®
Rev 3, 23-Dec-11
REG1, REG2, REG3 Turn-On Delay
Each of REG1, REG2 and REG3 features a
programmable Turn-On Delay which help ensure a
reliable qualification. This delay is programmed by
DELAY[2:0], as shown in Table 8.
Operating Mode
By default, REG1, REG2, and REG3 each operate
in fixed-frequency PWM mode at medium to heavy
loads, while automatically transitioning to a
proprietary power-saving mode at light loads in
order to maximize standby battery life. In
applications where low noise is critical, force fixedfrequency PWM operation across the entire load
current range, at the expense of light-load
efficiency, by setting the MODE[ ] bit to 1.
OK[ ] and Output Fault Interrupt
Each DC/DC features a power-OK status bit that
can be read by the system microprocessor via the
I2C interface. If an output voltage is lower than the
power-OK threshold, typically 7% below the
programmed regulation voltage, that regulator's
OK[ ] bit will be 0.
If a DC/DC's nFLTMSK[-] bit is set to 1, the
ACT8938 will interrupt the processor if that DC/DC's
output voltage falls below the power-OK threshold.
In this case, nIRQ will assert low and remain
asserted until either the regulator is turned off or
back in regulation, and the OK[ ] bit has been read
via I2C.
PCB Layout Considerations
High switching frequencies and large peak currents
make PC board layout an important part of stepdown DC/DC converter design. A good design
minimizes excessive EMI on the feedback paths
and voltage gradients in the ground plane, both of
which can result in instability or regulation errors.
Step-down DC/DCs exhibit discontinuous input
current, so the input capacitors should be placed as
close as possible to the IC, and avoiding the use of
via if possible. The inductor, input filter capacitor,
and output filter capacitor should be connected as
close together as possible, with short, direct, and
wide traces. The ground nodes for each regulator's
power loop should be connected at a single point in
a star-ground configuration, and this point should
be connected to the backside ground plane with
multiple via. The output node for each regulator
should be connected to its corresponding OUTx pin
through the shortest possible route, while keeping
sufficient distance from switching nodes to prevent
noise injection. Finally, the exposed pad should be
directly connected to the backside ground plane
using multiple via to achieve low electrical and
thermal resistance.
Table 7:
REGx/VSET[ ] Output Voltage Setting
REGx/VSET[2:0]
REGx/VSET[5:3]
000
001
010
011
100
101
110
111
000
0.600
0.800
1.000
1.200
1.600
2.000
2.400
3.200
001
0.625
0.825
1.025
1.250
1.650
2.050
2.500
3.300
010
0.650
0.850
1.050
1.300
1.700
2.100
2.600
3.400
011
0.675
0.875
1.075
1.350
1.750
2.150
2.700
3.500
100
0.700
0.900
1.100
1.400
1.800
2.200
2.800
3.600
101
0.725
0.925
1.125
1.450
1.850
2.250
2.900
3.700
110
0.750
0.950
1.150
1.500
1.900
2.300
3.000
3.800
111
0.775
0.975
1.175
1.550
1.950
2.350
3.100
3.900
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ACT8938
®
Rev 3, 23-Dec-11
LOW-NOISE, LOW-DROPOUT LINEAR REGULATORS
General Description
REG4, REG5, REG6, and REG7 are low-noise,
low-dropout linear regulators (LDOs) that supply up
to 150mA, 150mA, 320mA, and 320mA,
respectively. Each LDO has been optimized to
achieve low noise and high-PSRR, achieving more
than 65dB PSRR at frequencies up to 10kHz.
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.
Compensation
to that LDO's ON[ ] bit. The regulator accept rising
or falling edge of ON[ ] bit as on/off signal. To
enable the regulator, clear ON[ ] to 0 first then set to
1. To disable the regulator, set ON[ ] to 1 first then
clear it to 0.
REG4, REG5, REG6, REG7 Turn-on Delay
Each of REG4, REG5, REG6 and REG7 features a
programmable Turn-on Delay which help ensure a
reliable qualification. This delay is programmed by
DELAY[2:0], as shown in Table 8.
Table 8:
REGx/DELAY[ ] Turn-On Delay
DELAY[2] DELAY[1] DELAY[0] TURN-ON DELAY
0
0
0
0 ms
0
0
1
2 ms
0
1
0
4 ms
The LDOs are internally compensated and require
very little design effort, simply select input and
output capacitors according to the guidelines below.
0
1
1
8 ms
1
0
0
16 ms
1
0
1
32 ms
Input Capacitor Selection
1
1
0
64 ms
Each LDO requires a small ceramic input capacitor
to supply current to support fast transients at the
input of the LDO. Bypassing each INL pin to GA
with 1μF. High quality ceramic capacitors such as
X7R and X5R dielectric types are strongly
recommended.
1
1
1
128 ms
Output Capacitor Selection
Each LDO requires a small ceramic output
capacitor for stability. Capacitance value is 1.5μF
for REG4 and REG5, 3.3μF for REG6 and REG7.
For best performance, each output capacitor should
be connected directly between the output and GA
pins, as close to the output as possible, and with a
short, direct connection. High quality ceramic
capacitors such as X7R and X5R dielectric types
are strongly recommended.
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 Table 7.
Enable / Disable Control
During normal operation, each LDO may be
enabled or disabled via the I2C interface by writing
Output Discharge
Each of the ACT8938’s LDOs features an optional
output discharge function, which discharges the
output to ground through a 1.5kΩ resistance when
the LDO is disabled. This feature may be enabled
or disabled by setting DIS[-]; set DIS[-] to 1 to
enable this function, clear DIS[-] to 0 to disable it.
Low-Power Mode
Each of ACT8938's LDOs features a LOWIQ[-] bit
which, when set to 1, reduces the LDO's quiescent
current by about 16%, saving power and extending
battery lifetime.
OK[ ] and Output Fault Interrupt
Each LDO features a power-OK status bit that
be read by the system microprocessor via
interface. If an output voltage is lower than
power-OK threshold, typically 11% below
programmed regulation voltage, the value of
regulator's OK[-] bit will be 0.
If a LDO's nFLTMSK[-] bit is set to 1, the ACT8938
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
either the regulation is turned off or back in
regulation, and the OK[-] bit has been read via I2C.
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can
the
the
the
that
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®
ACT8938
Rev 3, 23-Dec-11
PCB Layout Considerations
The ACT8938’s LDOs provide good DC, AC, and
noise performance over a wide range of operating
conditions, and are relatively insensitive to layout
considerations. When designing a PCB, however,
careful layout is necessary to prevent other circuitry
from degrading LDO performance.
A good design places input and output capacitors
as close to the LDO inputs and output as possible,
and utilizes a star-ground configuration for all
regulators to prevent noise-coupling through
ground. Output traces should be routed to avoid
close proximity to noisy nodes, particularly the SW
nodes of the DC/DCs.
REFBP is a noise-filtered reference, and internally
has a direct connection to the linear regulator
controller. Any noise injected into REFBP will
directly affect the outputs of the linear regulators,
and therefore special care should be taken to
ensure that no noise is injected to the outputs via
REFBP. As with the LDO output capacitors, the
REFBP bypass capacitor should be placed as close
to the IC as possible, with short, direct connections
to the star-ground. Avoid the use of via whenever
possible. Noisy nodes, such as from the DC/DCs,
should be routed as far away from REFBP as
possible.
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ACT8938
®
Rev 3, 23-Dec-11
ActivePathTM CHARGER
General Description
The ACT8938 features an advanced battery
charger that incorporates the patent-pending
ActivePath architecture for system power selection.
This combination of circuits provides a complete,
advanced battery-management system that
automatically selects the best available input
supply, manages charge current to ensure system
power availability, and provides a complete, highaccuracy (±0.5%), thermally regulated, full-featured
single-cell linear Li+ charger that can withstand
input voltages of up to 12V.
In an input over-voltage condition this circuit limits
VVSYS to 4.6V, protecting any circuitry connected to
VSYS from the over-voltage condition, which may
exceed this circuitry's voltage capability. This circuit
is capable of withstanding input voltages of up to
12V.
Table 9:
Input Over-Voltage Protection Setting
OVPSET[1]
OVPSET[0]
OVP THRESHOLD
0
0
6.6V
0
1
7.0V
ActivePath Architecture
1
0
7.5V
The ActivePath architecture
important functions:
1
1
8.0V
performs
three
1) System Configuration Optimization
2) Input Protection
3) Battery-Management
System Configuration Optimization
The ActivePath circuitry monitors the state of the
input supply, the battery, and the system, and
automatically reconfigures itself to optimize the
power system. If a valid input supply is present,
ActivePath powers the system from the input while
charging the battery in parallel. This allows the
battery to charge as quickly as possible, while
supplying the system. If a valid input supply is not
present, ActivePath powers the system from the
battery. Finally, if the input is present and the
system current requirement exceeds the capability
of the input supply, ActivePath allows system power
to be drawn from both the battery and the input
supply.
Input Protection
Input Over-Voltage Protection
The ActivePath circuitry features input over-voltage
protection circuitry. This circuitry disables charging
when the input voltage exceeds the voltage set by
OVPSET[-] as shown in Table 9, but stands off the
input voltage in order to protect the system. Note
that the adjustable OVP threshold is intended to
provide the charge cycle with adjustable immunity
against upward voltage transients on the input, and
is not intended to allow continuous charging with
input voltages above the charger's normal operating
voltage range. Independent of the OVPSET[-]
setting, the charge cycle is not allowed to resume
until the input voltage falls back into the charger's
normal operating voltage range (i.e. below 6.0V).
Input Supply Overload Protection
The ActivePath circuitry monitors and limits the total
current drawn from the input supply to a value set
by the ACIN and CHGLEV inputs, as well as the
resistor connected to ISET. Drive ACIN to a logiclow for “USB Mode”, which limits the input current to
either 100mA, when CHGLEV is driven to a logiclow, or 450mA, when CHGLEV is driven to a logichigh. Drive ACIN to a logic-high for “AC-Mode”,
which limits the input current to 2A, typically.
Input Under Voltage Lockout
If the input voltage applied to CHGIN falls below
3.5V (typ), an input under-voltage condition is
detected and the charger is disabled. Once an input
under-voltage condition is detected, a new charge
cycle will initiate when the input exceeds the undervoltage threshold by at least 500mV.
Battery Management
The ACT8938 features a full-featured, intelligent
charger for Lithium-based cells, and was designed
specifically to provide a complete charging solution
with minimum system design effort.
The core of the charger is a CC/CV (ConstantCurrent/Constant-Voltage), linear-mode charge
controller. This controller incorporates current and
voltage sense circuitry, an internal 70mΩ power
MOSFET, thermal-regulation circuitry, a fullfeatured state machine that implements charge
control and safety features, and circuitry that
eliminates the reverse blocking diode required by
conventional charger designs.
The charge termination voltage is highly accurate
(±0.5%), and features a selection of charge safety
time-out periods that protect the system from
operation with damaged cells. Other features
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ACT8938
®
Rev 3, 23-Dec-11
include pin-programmable fast-charge current and
one current-limited nSTAT output that can directly
drive LED indicator or provide a logic-level status
signal to the host microprocessor.
a logic-high, or 100mA, if CHGLEV is driven to a
logic-low.
Dynamic Charge Current Control (DCCC)
Note that the actual charge current may be limited
to a current lower than the programmed fast charge
current due to the ACT8938’s internal thermal
regulation loop. See the Thermal Regulation section
for more information.
The ACT8938's ActivePath charger features
dynamic charge current control (DCCC) circuitry,
which acts to ensure that the system remains
powered while operating within the maximum output
capability of the power adapter. The DCCC circuitry
continuously monitors VVSYS, and if the voltage at
VSYS drops by more than 200mV, the DCCC
circuitry automatically reduces charge current in
order to prevent VVSYS from continuing to drop.
Charge Current Programming
The ACT8938's ActivePath charger features a
flexible charge current-programming scheme that
combines the convenience of internal charge
current programming with the flexibility of resistor
based charge current programming. Current limits
and charge current programming are managed as a
function of the ACIN and CHGLEV pins, in
combination with RISET, the resistance connected to
the ISET pin.
ACIN is a logic input that configures the current-limit
of ActivePath's linear regulator as well as that of the
battery charger. ACIN features a precise 1.2V logic
threshold, so that the input voltage detection
threshold may be adjusted with a simple resistive
voltage divider. This input also allows a simple, lowcost dual-input charger switch to be implemented
with just a few, low-cost components.
When the voltage at ACIN is above the 1.2V
threshold, the charger operates in “AC-Mode” with a
charge current programmed by RISET, and the RISET
is given by:
RISET (kΩ) = 2336 × (1V/ICHG (mA)) - 0.205
With a given RISET then charge current will reduce 5
times when CHGLEV is driven low.
When ACIN is below the 1.2V threshold, the
charger operates in “USB-Mode”, with a maximum
CHGIN input current and charge current defined by
the CHGLEV input; 450mA, if CHGLEV is driven to
The ACT8938's charge
summarized in Table 10.
current
settings
are
Charger Input Interrupts
In order to ease input supply detection and
eliminate the size and cost of external detection
circuitry, the charger has the ability to generate
interrupts based upon the status of the input supply.
This function is capable of generating an interrupt
when the input is connected, disconnected, or both.
An interrupt is generated any time the input supply
is connected when INSTAT[ ] bit is set to 1 and the
INCON[-] bit is set to 1, and an interrupt is
generated any time the input supply is disconnected
when INSTAT[ ] bit is set to 1 and the INDIS[ ] bit is
set to 1.
INDAT[-] indicates the status of the CHGIN input
supply. A value of 1 indicates that a valid CHGIN
input (CHGIN UVLO Threshold<VCHGIN<CHGIN
OVP Threshold) is present, a value of 0 indicates a
valid input is not present.
When an interrupt is generated by the input supply,
reading the INSTAT[ ] returns a value of 1.
INSTAT [ ] is automatically cleared to 0 upon
reading. When no interrupt is generated by the
input supply, reading the INSTAT[ ] returns a value
of 0.
When responding to an Input Status Interrupt, it is
often useful to know the state of the ACIN input. For
example, in a dual-input charger application
knowing the state of the ACIN input can identify
which type of input supply has been connected. The
state of the ACIN input can be read at any time by
reading the ACINSTAT[-] bit, where a value of 1
indicates that the voltage at ACIN is above the 1.2V
threshold (indicating that a wall-cube has been
attached), and a value of 0 indicates that the
voltage is below this threshold (indicating that ACIN
input is not valid and USB supply input is selected).
Table 10:
ACIN and CHGLEV Inputs
ACIN
CHGLEV
CHARGE CURRENT
(mA)
PRECONDITION CHARGE CURRENT
(mA)
0
0
90
45
0
1
450
45
1
0
ICHG/5
10% × ICHG
1
1
ICHG
10% × ICHG
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ACT8938
®
Rev 3, 23-Dec-11
Figure 6:
Typical Li+ charge profile and ACT8938 charge states
A: PRECONDITION State
B: FAST-CHARGE State
C: TOP-OFF State
D: END-OF-CHARGE State
Figure 7:
Charger State Diagram
TEMP NOT OK
ANY STATE
(VCHGIN < VBAT) OR (VCHGIN < VCHGIN UVLO)
OR (VCHGIN > VOVP) OR (SUSCHG[ ] = 1)
SUSPEND
TEMP-FAULT
(VCHGIN > VBAT) AND (VCHGIN > VCHGIN UVLO)
AND (VCHGIN < VOVP) AND (SUSCHG[ ] = 0)
TEMP OK
PRECONDITION
TIME-OUT-FAULT
PRECONDITION
Time-out
Total Time-out
(VBAT > 2.85V) AND
(TQUAL = 32ms)
FAST-CHARGE
(VBAT = VTERM ) AND
(TQUAL = 32ms)
(VBAT < VTERM - 205mV )
AND (TQUAL = 32ms)
TOP-OFF
(IBAT < 10% x ICHG) OR (Total
Time-out) AND (TQUAL = 32ms)
END-OF-CHARGE
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ACT8938
®
Rev 3, 23-Dec-11
Charge-Control State Machine
PRECONDITION State
A new charging cycle begins with the
PRECONDITION state, and operation continues in
this state until VBAT exceeds the Precondition
Threshold Voltage. When operating in
PRECONDITION state, the cell is charged at 10%
of the programmed maximum fast-charge constant
current, ICHG.
Once VBAT reaches the Precondition Threshold
Voltage, the state machine jumps to the FASTCHARGE state. If VBAT does not reach the
Precondition Threshold Voltage before the
Precondition Time-out period expires, then the state
machine jumps to the TIME-OUT-FAULT state in
order to prevent charging a damaged cell. See the
Charge Safety Timers section for more information.
FAST-CHARGE State
In the FAST-CHARGE state, the charger operates
in constant-current (CC) mode and regulates the
charge current to the current set by RISET . Charging
continues in CC mode until VBAT reaches the charge
termination voltage (VTERM), at which point the statemachine jumps to the TOP-OFF state. If VBAT does
not reach VTERM before the total time out period
expires then the state-machine will jump to the
“EOC” state and will re-initiate a new charge cycle
after 32ms “relax”. See the Current Limits and
Charge Current Programming sections for more
information about setting the maximum charge
current.
TOP-OFF State
In the TOP-OFF state, the cell charges in constantvoltage (CV) mode. In CV mode operation, the
charger regulates its output voltage to the 4.20V
charge termination voltage, and the charge current
is naturally reduced as the cell approaches full
charge. Charging continues until the charge current
drops to END-OF-CHARGE current threshold, at
which point the state machine jumps to the ENDOF-CHARGE (EOC) state.
If the state-machine does not jump out of the TOPOFF state before the Total-Charge Time-out period
expires, the state machine jumps to the EOC state
and will re-initiate a new charge cycle if VBAT falls
below termination voltage 205mV (typ). For more
information about the charge safety timers, see the
Charging Safety Times section.
END-OF-CHARGE (EOC) State
In the END-OF-CHARGE (EOC) state, the charger
presents a high-impedance to the battery,
minimizing battery current drain and allowing the
cell to “relax”. The charger continues to monitor the
cell voltage, and re-initiates a charging sequence if
the cell voltage drops to 205mV (typ) below the
charge termination voltage.
SUSPEND State
The state-machine jumps to the SUSPEND state
any time the battery is removed, and any time the
input voltage either falls below the CHGIN UVLO
threshold or exceeds the OVP threshold. Once
none of these conditions are present, a new charge
cycle initiates.
A charging cycle may also be suspended manually
by setting the SUSPEND[ ] bit. In this case, initiate
a new charging sequence by clearing SUSPEND[ ]
to 0.
State Machine Interrupts
The charger features the ability to generate
interrupts when the charger state machine
transitions, based upon the status of the CHG_ bits.
Set CHGEOCIN[ ] bit to 1 and CHGSTAT[ ] bit to 1
to generate an interrupt when the charger state
machine goes into the END-OF-CHARGE (EOC)
state. Set CHGEOCOUT[ ] bit to 1 and CHGSTAT[ ]
bit to 1 to generate an interrupt when the charger
state machine exits the EOC state.
CHGDAT[ ] indicates the status of the charger state
machine. A value of 1 indicates that the charger
state machine is in END-OF-CHARGE state, a
value of 0 indicates the charger state machine is in
other states.
When an interrupt is generated by the charger state
machine, reading the CHGSTAT[ ] returns a value
of 1. CHGSTAT[ ] is automatically cleared to 0 upon
reading. When no interrupt is generated by the
charger state machine, reading the CHGSTAT[ ]
returns a value of 0.
For additional information about the charge cycle,
CSTATE[0:1] may be read at any time via I2C to
determine the current charging state.
Table 11:
Charging Status Indication
CSTATE[0] CSTATE[1]
1
1
PRECONDITION State
1
0
FAST-CHARGE/
TOP-OFF State
0
1
END-OF-CHARGE State
0
0
SUSPEND/DISABLED/
FAULT State
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STATE MACHINE STATUS
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ACT8938
®
Rev 3, 23-Dec-11
Thermal Regulation
Table 13:
The charger features an internal thermal regulation
loop that monitors die temperature and reduces
charging current as needed to ensure that the die
temperature does not exceed the thermal regulation
threshold of 110°C. This feature protects against
excessive junction temperature and makes the
device more accommodating to aggressive thermal
designs. Note, however, that attention to good
thermal designs is required to achieve the fastest
possible charge time by maximizing charge current.
Total Safety Timer Setting
Charge Safety Timers
Charge Status Indicator
The charger features programmable charge safety
timers which help ensure a safe charge by
detecting potentially damaged cells. These timers
are programmable via the PRETIMO[1:0] and
TOTTIMO[1:0] bits, as shown in Table 12 and Table
13. Note that in order to account for reduced charge
current resulting from DCCC operation, the charge
time-out periods are extended proportionally to the
reduction in charge current. As a result, the actual
safety period may exceed the nominal timer period.
The charger provides a charge-status indicator
output, nSTAT. nSTAT is an open-drain output
which sinks current when the charger is in an
active-charging state, and is high-Z otherwise.
nSTAT features an internal 8mA current limit, and is
capable of directly driving a LED without the need
of a current-limiting resistor or other external
circuitry. To drive an LED, simply connect the LED
between nSTAT pin and an appropriate supply,
such as VSYS. For a logic-level charge status
indication, simply connect a resistor from nSTAT to
an appropriate voltage supply.
Charger Timer Interrupts
TOTTIMO[1]
TOTTIMO[0]
TOTAL TIME-OUT
PERIOD
0
0
3 hrs
0
1
4 hrs
1
0
5 hrs
1
1
Disabled
The charger features the ability to generate
interrupts based upon the status of the charge
timers. Set the TIMRPRE[ ] bit to 1 and
TIMRSTAT[ ] bit to 1 to generate an interrupt when
the Precondition Timer expires. Set the TIMRTOT[ ]
bit to 1 and TIMRSTAT[ ] bit to 1 to generate an
interrupt when the Total-Charge Timer expires.
Table 14:
Charging Status Indication
TIMRDAT[ ] indicates the status of the charge
timers. A value of 1 indicates a precondition timeout or a total charge time-out occurs, a value of 0
indicates other cases.
When an interrupt is generated by the charge
timers, reading the TIMRSTAT[ ] returns a value of
1. TIMRSTAT[ ] is automatically cleared to 0 upon
reading. When no interrupt is generated by the
charge timers, reading the TIMRSTAT[ ] returns a
value of 0.
Table 12:
PRECONDITION Safety Timer Setting
PRETIMO[1]
PRETIMO[0]
PRECONDITION
TIME-OUT PERIOD
0
0
40 mins
0
1
60 mins
1
0
80 mins
1
1
Disabled
STATE
nSTAT
PRECONDITION
Active
FAST-CHARGE
Active
TOP-OFF
Active
END-OF-CHARGE
High-Z
SUSPEND
High-Z
TEMPERATURE FAULT
High-Z
TIME-OUT-FAULT
High-Z
Reverse-Current Protection
The charger includes internal reverse-current
protection circuitry that eliminates the need for
blocking diodes, reducing solution size and cost as
well as dropout voltage relative to conventional
battery chargers. When the voltage at CHGIN falls
below VBAT, the charger automatically reconfigures
its power switch to minimize current drawn from the
battery.
Battery Temperature Monitoring
In a typical application, the TH pin is connected to
the battery pack's thermistor input, as shown in
Figure 8. The charger continuously monitors the
temperature of the battery pack by injecting a
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ACT8938
®
Rev 3, 23-Dec-11
102μA (typ) current into the thermistor (via the TH
pin) and sensing the voltage at TH. The voltage at
TH is continuously monitored, and charging is
suspended if the voltage at TH exceeds either of
the internal VTHH and VTHL thresholds of 0.5V and
2.51V, respectively.
Figure 8:
Simple Configuration
The net resistance (from TH to GA) required to
cross the thresholds are given by:
102μA × RNOM × kHOT = 0.5V → RNOM × kHOT
≈ 5kΩ
102μA × RNOM × kCOLD = 2.51V → RNOM ×
kCOLD ≈ 25kΩ
where RNOM is the nominal thermistor resistance
at room temperature, and kHOT and kCOLD
represent the ratios of the thermistor's resistance at
the desired hot and cold thresholds, respectively, to
the resistance at 25°C.
Battery Temperature Interrupts
In order to ease detecting the status of the battery
temperature, the charger features the ability to
generate interrupts based upon the status of the
battery temperature. Set the TEMPOUT[ ] bit to 1
and TEMPSTAT[ ] bit to 1 to generate an interrupt
when battery temperature goes out of the valid
temperature range. Set the TEMPIN[ ] bit to 1 and
TEMPSTAT[ ] bit to 1 to generate an interrupt when
battery temperature returns to the valid range.
TEMPDAT[ ] indicates the status of the battery
temperature. A value of 1 indicates the battery
temperature is inside of the valid range, a value of 0
indicates the battery is outside of the valid range.
When an interrupt is generated by the battery
temperature event, reading the TEMPSTAT[ ]
returns a value of 1. TEMPSTAT[ ] is automatically
cleared to 0 upon reading. When no interrupt is
generated by the battery temperature event,
reading the TEMPSTAT[ ] returns a value of 0.
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ACT8938
®
Rev 3, 23-Dec-11
TQFN55-40 PACKAGE OUTLINE AND DIMENSIONS
SYMBOL
A
A1
DIMENSION IN
MILLIMETERS
DIMENSION IN
INCHES
MIN
MAX
MIN
MAX
0.700
0.800
0.028
0.031
0.200 REF
0.008 REF
A2
0.000
0.050
0.000
0.002
b
0.150
0.250
0.006
0.010
D
4.900
5.100
0.193
0.201
E
4.900
5.100
0.193
0.201
D2
3.450
3.750
0.136
0.148
E2
3.450
3.750
0.136
0.148
e
L
R
0.400 BSC
0.300
0.500
0.300
0.016 BSC
0.012
0.020
0.012
Active-Semi, Inc. reserves the right to modify the circuitry or specifications without notice. Users should evaluate each
product to make sure that it is suitable for their applications. Active-Semi products are not intended or authorized for use
as critical components in life-support devices or systems. Active-Semi, Inc. does not assume any liability arising out of
the use of any product or circuit described in this datasheet, nor does it convey any patent license.
Active-Semi and its logo are trademarks of Active-Semi, Inc. For more information on this and other products, contact
[email protected] or visit http://www.active-semi.com.
®
is a registered trademark of Active-Semi.
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ActivePMUTM and ActivePathTM are trademarks of Active-Semi.
I2CTM is a trademark of NXP.
www.active-semi.com
Copyright © 2011 Active-Semi, Inc.