NSC LP3918 Battery charge management and regulator unit Datasheet

LP3918
Battery Charge Management and Regulator Unit
General Description
Features
The LP3918 is a fully integrated charger and multi-regulator
unit designed for CDMA cellular phones. The LP3918 contains a Li-Ion battery charger, 7 low noise low dropout (LDO)
voltage regulators and a high-speed serial interface to program on/off conditions and output voltages of individual regulators, and also to read status information from the PMU.
The Li-Ion charger integrates a power FET, reverse current
blocking diode, sense resistor with current monitor output,
and requires only a few external components. Charging is
thermally regulated to obtain the most efficient charging rate
for a given ambient temperature.
LDO regulators provide high PSRR and low noise ideally suited for supplying power to both analog and digital loads.
■ Fully integrated Li-Ion battery charger with thermal
Applications
■
■
■
■
■
CDMA Phone Handsets
Low Power Wireless Handsets
Handheld Information Appliances
Personal Media Players
Digital Cameras
regulation
■ USB Charge Mode.
■ 7 Low Noise LDO’s
■
■
■
■
■
2 x 300 mA
3 x 150 mA
2 x 80 mA
I2C compatible interface for controlling LDO outputs and
charger operation
Thermal shutdown
Under Voltage Lockout
25-bump Thin micro-SMD package 2.5 x 2.5 mm
Options available on request, please contact sales office
for further information;
- Level detect on HF_PWR & PWR_ON
- LDO Charging mode
- Custom Default Settings on Charger, and LDO O/P's.
Key Specifications
■
■
■
■
50mA to 950mA Programmable Charge Current
3.0V to 5.5V Input Voltage Range
200mV typ. Dropout Voltage on 300 mA LDO’s
2% (typ) Output Voltage Accuracy on LDO’s
Simplified Functional Block Diagram
20211601
© 2007 National Semiconductor Corporation
202116
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LP3918 Battery Charge Management and Regulator Unit
October 2007
LP3918
Device Pin Diagram
LP3918 25 pin micro-SMD Package
TOP VIEW
20211634
Package Marking Information
20211604
—
—
—
—
The physical placement of the package marking will vary from part to part.
Date Code. XYTT format. ‘XY’ 2 digit date code; ‘TT’ – dierun code
MNK - Package Marking
See National web page for more info - http://www.national.com/quality/marking_conventions.html
Ordering Information
Order Number
Connector Debounce
LDO MODE
Package Marking
LP3918TL
NO
NO
3918
LP3918TLX
LP3918TL-L
NO
YES
3918L
YES
NO
3918A
250 units, Tape & Reel
1000 units, Tape & Reel
LP3918TLX-A
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250 units, Tape & Reel
1000 units, Tape & Reel
LP3918TLX-L
LP3918TL-A
Supplied As
250 units, Tape & Reel
1000 units, Tape & Reel
2
LP3918
LP3918 Pin Descriptions
Pin #
Type
Description
A1
IMON
Name
A
Charge current monitor output. This pin presents an analog voltage representation of the
input charging current. VIMON(mV) = (2.47 x ICHG)(mA).
A2
PS_HOLD
DI
Input for power control from external processor/controller.
A3
VSS
G
Digital Ground pin
A4
RESET_N
DO
Reset Output. Pin stays LOW during power up sequence. 60ms after LDO1 (CORE) is
stable this pin is asserted HIGH.
A5
ACOK_N
DO
AC Adapter indicator, LOW when 4.5V – 6.0V present at CHG_IN.
B1
CHG_IN
P
DC power input to charger block from wall or car power adapters.
B2
PWR_ON
DI
Power up sequence starts when this pin is set HIGH. Internal 500kΩ pull-down resistor.
B3
SCL
DI
Serial Interface Clock input. External pull up resistor is needed, typ 1.5kΩ
B4
PON_N
DO
Active low signal is PWR_ON inverted
B5
LDO7
C1
C2
C3
SDA
C4
TX_EN
DI
Enable control for LDO6 (TX). HIGH = Enable, LOW = Disable.
C5
LDO6
A
LDO6 Output (TX)
D1
VIN1
P
Battery Input for LDO1 - 2
D2
TCXO_EN
DI
Enable control for LDO4 (TCXO). HIGH = Enable, LOW = Disable.
D3
GNDA
G
Analog Ground pin
D4
RX_EN
DI
Enable control for LDO5 (RX). HIGH = Enable, LOW = Disable.
D5
LDO5
A
LDO5 Output (RX)
E1
LDO1
A
LDO1 Output (CORE)
E2
LDO2
A
LDO2 Output (DIGI)
E3
LDO3
A
LDO3 Output (ANA)
E4
LDO4
A
LDO4 Output (TCXO)
E5
VIN2
P
Battery Input for LDO3 - 7
A
LDO7 Output (GP)
BATT
P
Main battery connection. Used as a power connection for current delivery to the battery.
HF_PWR
DI
Power up sequence starts when this pin is set HIGH. Internal 500kΩ pull-down resistor.
A: Analog.
G: Ground.
DI/O
D: Digital.
O: Output.
Serial Interface, Data Input/Output Open Drain output, external pull up resistor is needed,
typ 1.5kΩ.
I: Input.
DI/O: Digital Input/Output.
P: Power.
3
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LP3918
Applications Schematic Diagram
20211605
•
•
Device Description
The LP3918 Charge Management and Regulator Unit is designed to supply charger and voltage output capabilities for
mobile systems, e.g. CDMA handsets. The device provides a
Li-Ion charging function and 7 regulated outputs. Communication with the device is via an I2C compatible serial interface
that allows function control and status read-back.
The battery charge management section provides a programmable CC/CV linear charge capability. Following a normal charge cycle a maintenance mode keeps battery voltage
between programmable levels. Power levels are thermally
regulated to obtain optimum charge levels over the ambient
temperature range.
•
•
•
•
•
•
REGULATORS
7 Low dropout linear regulators provide programmable voltage outputs with current capabilities of 80mA, 150mA and
300mA as given in the table below. LDO1, LDO2 and LDO3
are powered up by default with LDO1 reaching regulation before LDO2 and LDO3 are started. LDO1, LDO3 and LDO7 can
be disabled/enabled via the serial interface. During power up
LDO1 and LDO2 must reach their regulation voltage detection
point for the device to power up and remain powered. LDO4,
LDO5 and LDO6 have external enable pins and may power
up following LDO2 as determined by their respective enable.
Under voltage lockout oversees device start up with preset
level of 2.85V(typ).
Charger Features
• Pre-charge, CC, CV and Maintenance modes
• USB Charge 100mA/450mA
• Integrated FET
• Integrated Reverse Current Blocking Diode
• Integrated Sense Resistor
• Thermal regulation
• Charge Current Monitor Output
• Programmable charge current 50mA - 950mA with 50mA
steps
• Default CC mode current 100mA
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Pre-charge current fixed 50mA
Termination voltage 4.1V, 4.2V (default), 4.3V, and 4.4V,
accuracy better than +/- 0.5% (typ)
Restart level 50mV, 100mV, 150mV (default) and 200mV
below Termination voltage
End of Charge 0.1C (default), 0.15C, 0.2C and 0.25C
Programmable Enable Control
Safety timer
Input voltage operating range 4.5V - 6.0V
LDO mode on LP3918TL-L option.
4
DEVICE PROGRAMMABILITY
An I2C compatible Serial Interface is used to communicate
with the device to program a series of registers and also to
read status registers. These internal registers allow control
over LDO outputs and their levels. The charger functions may
also be programmed to alter termination voltage, end of
charge current, charger restart voltage, full rate charge current, and also the charging mode.
This device internal logic is powered from LDO2.
TABLE 1. LDO Default Voltages
LDO
Function
mA
Default Voltage (V)
Startup Default
Enable Control
1
CORE
300
1.8
ON
SI
2
DIGI
300
3.0
ON
-
3
ANA
80
3.0
ON
SI
4
TCXO
80
3.0
OFF
TCXO_EN
5
RX
150
3.0
OFF
RX_EN
6
TX
150
3.0
OFF
TX_EN
7
GP
150
3.0
OFF
SI
TABLE 2. LDO Output Voltages Selectable via Serial Interface
LDO
mA
1.5
1.8
1.85
2.5
2.6
2.7
2.75
2.8
2.85
2.9
2.95
3.0
3.05
3.1
3.2
3.3
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
1
CORE
300
2
DIGI
300
3
ANA
80
4
TCXO
80
5
RX
150
+
+
+
+
+
+
+
+
6
TX
150
+
+
+
+
+
+
+
+
7
GP
150
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
5
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LP3918
POWER SUPPLY CONFIGURATIONS
At PMU start up, LDO1, LDO2 and LDO3 are always started
with their default voltages. The start up sequence of the LDO's
is given below.
Startup Sequence
LDO1 -> LDO2 -> LDO3
LDO's with external enable control (LDO4, LDO5, LDO6) start
immediately after LDO2 if enabled by logic high at their respective control inputs.
LDO7 (and LDO1 and 3) may be programmed to enable/disable once PS_HOLD has been asserted.
Default voltages for the LDOs are shown in Table 1 and Table
2 shows the voltages that may be programmed via the Serial
Interface.
LP3918
HF_PWR, PWR_ON
ACOK_N, SDA, SCL, RX_EN,
TX_EN, TCXO_EN, PS_HOLD,
RESET_N
All other pins
Junction Temperature (TJ)
Ambient Temperature (TA)
Absolute Maximum Ratings (Notes 1, 2)
If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales Office/
Distributors for availability and specifications.
CHG-IN,
VBATT =VIN1/2, BATT,HF_PWR
All other Inputs
Junction Temperature (TJ-MAX)
Storage Temperature
Max Continuous Power Dissipation
(PD-MAX) (Note 3)
ESD (Note 4)
Batt, VIN1, VIN2, HF_PWR,
CHG_IN, PWR_ON
All other pins
Operating Ratings
−0.3 to +6.5V
−0.3 to +6V
−0.3 to VBATT +0.3V,
max 6.0V
150°C
−40°C to +150°C
0V to 5.5V
0V to (VLDO2 + 0.3V)
0V to (VBATT + 0.3V)
−40°C to +125°C
-40 to 85°C
Thermal Properties
(Note 9)
Junction to Ambient Thermal
Resistance θJA
Internally Limited
Jedec Standard Thermal PCB
4L Cellphone Board
37°C/W
66°C/W
8kV HBM
2kV HBM
(Notes 1, 2)
CHG_IN
VBATT =VIN1/2, BATT
4.5 to 6.0V
3.0 to 5.5V
General Electrical Characteristics
Unless otherwise noted, VIN ( = VIN1 = VIN2 = BATT) = 3.6V, GND = 0V, CVIN1-2=10µF, CLDOX=1µF. Typical values and limits
appearing in normal type apply for TJ = 25°C. Limits appearing in boldface type apply over the entire junction temperature range
for operation, Ta = TJ = −40°C to +125°C. (Note 6)
Symbol
IQ(STANDBY)
Parameter
Standby Supply Current
Condition
Typ
VIN= 3.6V, UVLO on, internal logic
circuit on, all other circuits off
2
Limit
Min
Max
Units
10
µA
3.0
V
Power Monitor Functions
Battery Under-Voltage Lockout
VUVLO-R
Under Voltage Lock-out
VIN Rising
2.85
(Note 7)
160
2.7
Thermal Shutdown
TSD Threshold
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6
°C
Parameter
Condition
Typ
Limit
Min
Units
Max
LOGIC AND CONTROL INPUTS (LDO2 at 3.0V)
VIL
Input Low Level
VIH
Input High Level
IIL
Logic Input Current
PS_HOLD, SDA, SCL, RX_EN,
TCXO_EN, TX_EN
0.25*
VLDO2
V
PWR_ON, HF_PWR
0.25*
VBATT
V
PS_HOLD, SDA, SCL, RX_EN,
TCXO_EN, TX_EN
0.75*
VLDO2
V
PWR_ON, HF_PWR
0.75*
VBATT
V
All logic inputs except PWR_ON
and HF_PWR
-5
+5
µA
0V ≤ VINPUT ≤ VBATT
RIN
Input Resistance
PWR_ON, HF_PWR Pull-Down
resistance to GND(Note 7)
500
kΩ
LOGIC AND CONTROL OUTPUTS (LDO2 at 3.0V)
VOL
VOH
Output Low Level
Output High Level
PON_N, RESET_N, SDA,
ACOK_N
IOUT = 2mA
0.25*
V
VLDO2
PON_N, RESET_N, ACOK_N
IOUT = 2mA
0.75*
VLDO2
V
(Not applicable to Open Drain
Output SDA)
LDO1 (CORE) Electrical Characteristics
Unless otherwise noted, VIN ( = VIN1 = VIN2 = BATT) = 3.6V, GND = 0V, CVIN1-2=10µF, CLDOX=1µF. VOUT1 set to 3.0V output. Note
VINMIN is the greater of 3.0V or VOUT1+ 0.5V. Typical values and limits appearing in normal type apply for TJ = 25°C. Limits appearing
in boldface type apply over the entire junction temperature range for operation, Ta = TJ = −40°C to +125°C. (Note 6)
Symbol
VOUT1
IOUT1
Parameter
Output Voltage Accuracy
Condition
Typ
IOUT1 = 1mA, VOUT1= 3.0V
Output Voltage
Default
Output Current
VINMIN ≤ VIN ≤ 5.5V
Limit
Min
Max
−2
+2
−3
+3
1.8
Output Current Limit
VOUT1 = 0V
600
VDO1
Dropout Voltage
IOUT1 = 300mA, (Note 8)
200
ΔVOUT1
Line Regulation
VINMIN ≤ VIN ≤ 5.5V
Units
%
V
300
mA
280
mV
2
mV
IOUT1 = 1mA
Load Regulation
1mA ≤ IOUT1 ≤ 300mA
20
mV
en1
Output Noise Voltage
10Hz ≤ f ≤ 100KHz,
45
µVRMS
PSRR
Power Supply Rejection Ratio
65
dB
tSTART-UP
Start-Up Time from Shut-down
COUT = 1µF (Note 7)
F = 10kHz, COUT = 1µF
IOUT1 = 20mA (Note 7)
COUT = 1µF, IOUT1 = 300mA
60
170
µs
60
120
mV
(Note 7)
TTransient
Start-Up Transient Overshoot
COUT = 1µF, IOUT1 = 300mA
(Note 7)
7
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LP3918
Symbol
LP3918
LDO2 (DIGI) Electrical Characteristics
Unless otherwise noted, VIN ( = VIN1 = VIN2 = BATT) = 3.6V, GND = 0V, CVIN1-2=10µF, CLDOX=1µF. Note VINMIN is the greater of
3.0V or VOUT2+ 0.5V. Typical values and limits appearing in normal type apply for TJ = 25°C. Limits appearing in boldface type
apply over the entire junction temperature range for operation, Ta = TJ = −40°C to +125°C.(Note 6)
Symbol
VOUT2
IOUT2
Parameter
Output Voltage Accuracy
Condition
Typ
IOUT2 = 1mA, VOUT2= 3.0V
Output Voltage
Default
Output Current
VINMIN ≤ VIN ≤ 5.5V
Limit
Min
Max
−2
+2
−3
+3
3.0
Output Current Limit
VOUT2 = 0V
600
VDO2
Dropout Voltage
IOUT2 = 300mA (Note 8)
200
ΔVOUT2
Line Regulation
VINMIN ≤ VIN ≤ 5.5V
Units
%
V
300
mA
280
mV
2
mV
IOUT2 = 1mA
Load Regulation
1mA ≤ IOUT2 ≤ 300mA
20
mV
en2
Output Noise Voltage
10Hz ≤ f ≤ 100KHz,
45
µVRMS
PSRR
Power Supply Rejection Ratio
65
dB
COUT = 1µF (Note 7)
F = 10kHz, COUT = 1µF
IOUT2 = 20mA (Note 7)
tSTART-UP
Start-Up Time from Shut-down
COUT = 1µF, IOUT2 = 300mA
40
60
µs
5
30
mV
(Note 7)
tTransient
Start-Up Transient Overshoot
COUT = 1µF, IOUT2 = 300mA
(Note 7)
LDO3 (ANA), LDO4 (TCXO) Electrical Characteristics
Unless otherwise noted, VIN ( = VIN1 = VIN2 = BATT) = 3.6V, GND = 0V, CVIN1-2=10µF, CLDOX=1µF. TCXO_EN high. Note VINMIN
is the greater of 3.0V or VOUT3/4 + 0.5V. Typical values and limits appearing in normal type apply for TJ = 25°C. Limits appearing
in boldface type apply over the entire junction temperature range for operation, Ta = TJ = −40°C to +125°C. (Note 6)
Symbol
VOUT3, VOUT4
Parameter
Output Voltage Accuracy
Output Voltage
Condition
Typ
IOUT3/4 = 1mA, VOUT3/4= 3.0V
LDO3 default
3.0
LDO4 default
3.0
Output Current
VINMIN ≤ VIN ≤ 5.5V
Output Current Limit
VOUT3/4 = 0V
160
VDO3, VDO4
Dropout Voltage
IOUT3/4 = 80mA (Note 8)
180
ΔVOUT3 ,
Line Regulation
VINMIN ≤ VIN ≤ 5.5V
IOUT3, IOUT4
ΔVOUT4
Limit
Min
Max
−2
+2
−3
+3
Units
%
V
80
mA
220
mV
2
mV
IOUT3/4 = 1mA
Load Regulation
1mA ≤ IOUT3/4 ≤ 80mA
20
mV
en3,en4
Output Noise Voltage
10Hz ≤ f ≤ 100kHz,
COUT = 1µF (Note 7)
45
µVRMS
PSRR
Power Supply Rejection Ratio
F = 10kHz, COUT = 1µF
65
dB
tSTART-UP
Start-Up Time from Shut-down
COUT = 1µF, IOUT3/4 = 80mA
(Note 7)
40
60
µs
tTransient
Start-Up Transient Overshoot
COUT = 1µF, IOUT3/4 = 80mA
(Note 7)
5
30
mV
IOUT3/4 = 20mA (Note 7)
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8
Unless otherwise noted, VIN ( = VIN1 = VIN2 = BATT) = 3.6V, GND = 0V, CVIN1-2=10µF, CLDOX=1µF. RX_EN, TX_EN high. LDO7
Enabled via Serial Interface. Note VINMIN is the greater of 3.0V or VOUT5/6/7 + 0.5V. Typical values and limits appearing in normal
type apply for TJ = 25°C. Limits appearing in boldface type apply over the entire junction temperature range for operation, Ta =
TJ = −40°C to +125°C. (Note 6)
Symbol
Parameter
VOUT5,
Output Voltage
VOUT6, VOUT7
Output Voltage
Condition
Typ
IOUT5/6/7 = 1mA, VOUT5/6/7= 3.0V
LDO5 default
3.0
LDO6 default
3.0
LDO7 default
3.0
IOUT5, IOUT6, Output Current
IOUT7
Output Current Limit
VINMIN ≤ VIN ≤ 5.5V
VOUT5/6/7 = 0V
300
VDO5, VDO6,
VDO7
Dropout Voltage
IOUT5/6/7 = 150mA (Note 8)
180
ΔVOUT5,
Line Regulation
VINMIN ≤ VIN ≤ 5.5V
ΔVOUT6,
Limit
Min
Max
−2
+2
−3
+3
Units
%
V
150
mA
240
mV
2
mV
IOUT5/6/7 = 1mA
ΔVOUT7
Load Regulation
1mA ≤ IOUT5/6/7 ≤ 150mA
20
mV
en5, en6, en7
Output Noise Voltage
10Hz ≤ f ≤ 100kHz,
COUT = 1µF (Note 7)
45
µVRMS
PSRR
Power Supply Rejection Ratio
F = 10kHz, COUT = 1µF
65
dB
tSTART-UP
Start-Up Time from Shut-down
COUT = 1µF, IOUT5/6/7 = 150mA
(Note 7)
40
60
µs
tTransient
Start-Up Transient Overshoot
COUT = 1µF, IOUT5/6/7 = 150mA
(Note 7)
5
30
mV
IOUT5/6/7 = 20mA (Note 7)
9
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LP3918
LDO5 (RX), LDO6 (TX), LDO7 (GP) Electrical Characteristics
LP3918
Charger Electrical Characteristics
Unless otherwise noted, VCHG-IN = 5V, VIN ( = VIN1 = VIN2 = BATT) = 3.6V.CCHG_IN = 10µF, CBATT = 30µF. Charger set to default
settings unless otherwise noted. Typical values and limits appearing in normal type apply for TJ = 25°C. Limits appearing in
boldface type apply over the entire junction temperature range for operation, Ta = TJ = −25°C to +85°C. (Notes 6, 9)
Symbol
VCHG-IN
VOK_CHG
VTERM
ICHG
Parameter
Condition
Typ
Limit
Min
Max
Input Voltage Range
4.5
6.5
Operating Range
4.5
6
CHG_IN OK trip-point
VCHG_IN - VBATT (Rising)
200
VCHG_IN - VBATT (Falling)
50
Battery Charge
Termination voltage
Default
4.2
VTERM voltage tolerance
TJ = 25°C
Units
V
mV
V
-0.35
+0.35
TJ = 0°C to 85°C
-1
+1
%
Fast Charge Current
Accuracy
ICHG = 450mA
-10
+10
%
Programmable full-rate
charge current range
(default 100mA)
6.0V ≥ VCHG_IN ≥ 4.5V
50
950
mA
40
60
mA
VBATT < (VCHG_IN - VOK_CHG)
VFULL_RATE < VBATT < VTERM
(Note 10)
Default
100
Charge current
programming step
50
IPREQUAL
Pre-qualification current
VBATT = 2V
50
ICHG_USB
CHG_IN programmable
current in USB mode
5.5V ≥ VCHG_IN ≥ 4.5V
Low
VBATT < (VCHG_IN - VOK_CHG)
100
VFULL_RATE < VBATT < VTERM High
450
Default = 100mA
100
VBATT rising, transition from pre-qual
to full-rate charging
3.0
VFULL_RATE
Full-rate qualification
threshold
IEOC
End of Charge Current, % 0.1C option selected
of full-rate current
VRESTART
Restart threshold voltage VBATT falling, transition from EOC to
full-rate charge mode. Default options
selected - 4.05V
4.05
IMON Voltage 1
ICHG = 100mA
0.247
IMON Voltage 2
ICHG = 450mA
1.112
Regulated junction
temperature
(Note 7)
IMON
TREG
mA
2.9
3.1
10
V
%
3.97
4.13
V
115
0.947
1.277
V
°C
Detection and Timing (Note 7)
TPOK
Power OK deglitch time
VBATT < (VCC - VOK_CHG)
32
mS
TPQ_FULL
Deglitch time
Pre-qualification to full-rate charge
transition
230
mS
TCHG
Charge timer
Precharge mode
1
Hrs
Full Rate Charging Timeout
5
Constant Voltage Timeout
TEOC
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Deglitch time for end-ofcharge transition
5
230
10
mS
Unless otherwise noted, VIN ( = VIN1 = VIN2 = BATT) = 3.6V, GND = 0V, CVIN1-2=10µF, CLDOX=1µF, and VLDO2 (DIG) = 3.0V.
Typical values and limits appearing in normal type apply for TJ = 25°C. Limits appearing in boldface type apply over the entire
junction temperature range for operation, Ta = TJ = −40°C to +125°C. (Notes 6, 7)
Symbol
Parameter
Condition
Typ
Limit
Min
Max
400
Units
fCLK
Clock Frequency
tBF
Bus-Free Time between START
and STOP
1.3
µs
tHOLD
Hold Time Repeated START
Condition
0.6
µs
tCLK-LP
CLK Low Period
1.3
µs
tCLK-HP
CLK High Period
0.6
µs
tSU
Set-Up Time Repeated START
Condition
0.6
µs
tDATA-HOLD
Data Hold Time
50
ns
tDATA-SU
Data Set-Up Time
100
ns
tSU
Set-Up Time for STOP Condition
0.6
µs
tTRANS
Maximum Pulse Width of Spikes
that Must be Suppressed by the
Input Filter of both DATA & CLK
Signals
50
kHz
ns
Note 1: Absolute Maximum Ratings are limits beyond which damage to the device may occur. Operating Ratings are conditions under which operation of the
device is guaranteed. Operating Ratings do not imply guaranteed performance limits. For guaranteed performance limits and associated test conditions, see the
Electrical Characteristics tables.
Note 2: All voltages are with respect to the potential at the GND pin.
Note 3: Internal Thermal Shutdown circuitry protects the device from permanent damage.
Note 4: The human-body model is 100pF discharged through 1.5kΩ. The machine model is a 200pF capacitor discharged directly into each pin, MIL-STD-883
3015.7.
Note 5: Care must be exercised where high power dissipation is likely. The maximum ambient temperature may have to be derated.
Like the Absolute Maximum power dissipation, the maximum power dissipation for operation depends on the ambient temperature. In applications where high
power dissipation and/or poor thermal dissipation exists, the maximum ambient temperature may have to be derated. Maximum ambient temperature (TA_MAX)
is dependent on the maximum power dissipation of the device in the application (PD_MAX), and the junction to ambient thermal resistance of the device/package
in the application (θJA), as given by the following equation:
TA_MAX = TJ_MAX-OP – (θJA X PDMAX ).
Note 6: All limits are guaranteed. All electrical characteristics having room-temperature limits are tested during production with TJ = 25°C. All hot and cold limits
are guaranteed by correlating the electrical characteristics to process and temperature variations and applying statistical process control.
Note 7: Guaranteed by design.
Note 8: Dropout voltage is the input-to-output voltage difference at which the output voltage is 100mV below its nominal value. This specification does not apply
in cases it implies operation with an input voltage below the 3.0V minimum appearing under Operating Ratings. For example, this specification does not apply
for devices having 1.5V outputs because the specification would imply operation with an input voltage at or about 1.5V.
Note 9: Junction-to-ambient thermal resistance (θJA) is taken from thermal modelling result, performed under the conditions and guidelines set forth in the JEDEC
standard JESD51-7. The value of (θJA) of this product could fall within a wide range, depending on PWB material, layout, and environmental conditions. In
applications where high maximum power dissipation exists (high VIN, high IOUT), special care must be paid to thermal dissipation issues in board design.
Note 10: Full charge current is guaranteed for CHG_IN = 4.5 to 6.0V. At higher input voltages, increased power dissipation may cause the thermal regulation to
limit the current to a safe level, resulting in longer charging time.
11
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LP3918
Serial Interface
LP3918
Register Information, Slave Address Code 7h’7E
TABLE 3. Control Registers
Addr
Register
(default value)
8h'00
D7
D6
D5
D4
D3
D2
D1
D0
OP_EN
(0000 0101)
X
X
X
X
LDO7_EN
LDO3_EN
X
LDO1_EN
8h'01
LDO1PGM O/P
(0000 0001)
X
X
X
X
V1_OP[3]
V1_OP[2]
V1_OP[1]
V1_OP[0]
8h'02
LDO2PGM O/P
(0000 1011)
X
X
X
X
V2_OP[3]
V2_OP[2]
V2_OP[1]
V2_OP[0]
8h'03
LDO3PGM O/P
(0000 1011)
X
X
X
X
V3_OP[3]
V3_OP[2]
V3_OP[1]
V3_OP[0]
8h'04
LDO4PGM O/P
(0000 1011)
X
X
X
X
V4_OP[3]
V4_OP[2]
V4_OP[1]
V4_OP[0]
8h'05
LDO5PGM O/P
(0000 1011)
X
X
X
X
V5_OP[3]
V5_OP[2]
V5_OP[1]
V5_OP[0]
8h'06
LDO6PGM O/P
(0000 1011)
X
X
X
X
V6_OP[3]
V6_OP[2]
V6_OP[1]
V6_OP[0]
8h'07
LDO7PGM O/P
(0000 1011)
X
X
X
X
V7_OP[3]
V7_OP[2]
V7_OP[1]
V7_OP[0]
8h'0C
STATUS
(0000 0000)
PWR_ON
_TRIG
HF_PWR
_TRIG
CHG_IN
_TRIG
X
X
X
X
X
8h'10
CHGCNTL1
(0000 1001)
TOUT_
doubling
EN_Tout
En_EOC
X
EN_CHG
8h'11
CHGCNTL2
(0000 0001)
Prog_
ICHG[4]
Prog_
ICHG[3]
Prog_
ICHG[2]
Prog_
ICHG[1]
Prog_
ICHG[0]
8h'12
CHGCNTL3
(0001 0010)
VTERM[1]
VTERM[0]
Prog_
EOC[1]
Prog_
EOC[0]
Prog_
VRSTRT[1]
Prog_
VRSTRT[0]
EOC
Tout_
Fullrate
Tout_
Prechg
LDO Mode
Fullrate
PRECHG
8h'14 CHGSTATUS2
Tout_
ConstV
Bad_Batt
8h'1C MISC Control1
APU_TSD_EN
PS_HOLD
_DELAY
8h'13 CHGSTATUS1
X
(R/O)
USBMODE CHGMODE
Force EOC
_EN
_EN
Batt_Over
_Out
CHGIN_
OK_Out
Not Used
Bits are Read Only type.
Codes other than those shown in the table are disallowed.
Note that for Serial Interface operation and thus register control, LDO2 must be active to provide the power for the internal logic.
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12
The following table summarizes the supported output voltages for the LP3918. Default voltages after startup are highlighted in
bold.
TABLE 4.
Data Code
(Reg 01 - 07)
LDO1
V
LDO2
V
VLDO3
V
LDO4
V
LDO5
V
LDO6
V
LDO7
V
8h'00
1.5
1.5
8h'01
1.8
1.8
1.8
8h'02
1.85
1.85
1.85
8h'03
2.5
2.5
2.5
2.5
8h'04
2.6
2.6
2.6
8h'05
2.7
2.7
2.7
2.7
2.7
2.7
2.7
8h'06
2.75
2.75
2.75
2.75
2.75
2.75
2.75
8h'07
2.8
2.8
2.8
2.8
2.8
2.8
2.8
8h'08
2.85
2.85
2.85
2.85
2.85
2.85
2.85
8h'09
2.9
2.9
2.9
2.9
2.9
2.9
2.9
8h'0A
2.95
2.95
2.95
2.95
2.95
2.95
2.95
8h'0B
3.0
3.0
3.0
3.0
3.0
3.0
3.0
8h'0C
3.05
3.05
3.05
3.05
3.05
3.05
3.05
8h'0D
3.1
3.1
3.1
3.1
8h'0E
3.2
3.2
3.2
3.2
8h'0F
3.3
3.3
3.3
3.3
1.5
2.6
Charger Control Register 2
Note that Bits 7,6,5 are not used and must be set to 0 during write to this register.
CHARGER CURRENT PROGRAMMING
The following table summarizes the supported charging current values for the LP3918.
Default charge current after startup is highlighted in bold
TABLE 5. LP3918 Charger Current Programming
Address
Register ID
8h'11
CHGCNTL2
Address
Register ID
8h'11
CHGCNTL2
Address
Register ID
8h'11
CHGCNTL2
Current Selection Prog_ICHG<4..0> Bit 0 to Bit 4
00000
00001
00010
00011
00100
00101
00110
50mA
100mA
150mA
200mA
250mA
300mA
350mA
Current Selection Prog_ICHG<4..0> Bit 0 to Bit 4
00111
01000
01001
01010
01011
01100
01101
400mA
450mA
500mA
550mA
600mA
650mA
700mA
01110
01111
10000
10001
10010
750mA
800mA
850mA
900mA
950mA
Current Selection Prog_ICHG<4..0> Bit 0 to Bit 4
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LP3918
LDO Output Voltage Programming
LP3918
Charger Control Register 3
CHARGER TERMINATION VOLTAGE PROGRAMMING
TABLE 6. LP3918 Charger Termination Voltage Control
Address
8h'12
Register ID
VTERM Selection Bits
VTERM[1]
VTERM[0]
CHGCNTL3<5>
CHGCNTL3<4>
0
0
4.1
0
1
4.2 (Default)
1
0
4.3
1
1
4.4
CHGCNTL3
Termination Voltage(V)
END OF CHARGE CURRENT PROGRAMMING
TABLE 7. LP3918 EOC Current Control
Address
8h'12
Register ID
End Of Charge Current Selection Bits
PROG_EOC[1]
PROG_EOC[0]
CHGCNTL3<3>
CHGCNTL3<2>
0
0
0.1 (Default)
0
1
0.15C
1
0
0.2C
1
1
0.25C
CHGCNTL3
End Of Charge Current
CHARGING RESTART VOLTAGE PROGRAMMING
TABLE 8. LP3918 Charging Restart Voltage
Address
8h'12
Register ID
Charging Restart Voltage Selection Bits
PROG_VRSTRT[1]
PROG_VRSTRT[1]
CHGCNTL3<1>
CHGCNTL3<0>
0
0
0
1
VTERM - 100mV
1
0
VTERM - 150mV
1
1
VTERM - 200mV
CHGCNTL3
Restart Voltage(V)
VTERM - 50mV
Charger Control Register 1
CHARGING MODE SELECTION
Charging mode selection changes will only take place when the battery voltage is above the 3.0V pre-charge/Full-rate charge
threshold.
TABLE 9. LP3918 USB Charging Selection
Address
8h'10
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Register ID
CHGCNTL1
USB Charge Mode Control Bits
USB_Mode_En
CHG_Mode_En
CHGCNTL1<7>
CHGCNTL1<6>
Mode
Current
0
1
0
Fast Charge
Default or Selection
0
Fast Charge
Default or Selection
0
1
USB
100mA
1
1
USB
450mA
14
LP3918
Device Power Up and Shutdown Timing
Device Power Up Logic Timing. PWR_ON
20211637
15
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LP3918
Device Power Up Logic Timing. CHG_IN, HF_PWR
20211607
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16
LP3918
LP3918 Power On Behaviour (Failed PS_Hold)
20211608
LP3918 Normal Shutdown Behaviour
20211633
17
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LP3918
Functional Block Diagram
20211602
LP3918 Functional Block Diagram
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18
LP3918
Technical Description
BATTERY CHARGE MANAGEMENT
A charge management system allowing the safe charge and
maintenance of a Li-Ion battery is implemented on the
LP3918. This has a CC/CV linear charge capability with programmable battery regulation voltage and end of charge current threshold. The charge current in the constant current
mode is programmable and a maintenance mode monitors for
battery voltage drop to restart charging at a preset level. A
USB charging mode is also available with 2 charge current
levels.
20211638
FIGURE 1. LDO Mode Diagram
CHARGER FUNCTION
Following the correct detection of an input voltage at the
charger pin the charger enters a pre-charge mode. In this
mode a constant current of 50mA is available to charge the
battery to 3.0V. At this voltage level the charge management
applies the default (100mA) full rate constant current to raise
the battery voltage to the termination voltage level (default
4.2V). The full rate charge current may be programmed to a
different level at this stage. When termination voltage
(VTERM) is reached, the charger is in constant voltage mode
and a constant voltage of 4.2V is maintained. This mode is
complete when the end of charge current (default 0.1C) is
detected and the charge management enters the maintenance mode. In maintenance mode the battery voltage is
monitored for the restart level (4.05V at the default settings)
and the charge cycle is re-initiated to re-establish the termination voltage level.
For start up the EOC function is disabled. This function should
be enabled once start up is complete and a battery has been
detected. EOC is enabled via register CHGCNTL1, Table
10.
The full rate constant current rate of charge may be programmed to 19 levels from 50mA to 950mA. These values
are given in Table 5, and Table 12
The charge mode may be programmed to USB mode when
the charger input is applied and the battery voltage is above
3.0V. This provides two programmable current levels of
100mA and 450mA for a USB sourced supply input at
CHG_IN. Table 9
EOC
EOC is disabled by default and should be enabled when the
system processor is awake and the system detects that a
battery is present.
Programming Information
TABLE 10. Register Address 8h'10: CHGCNTL1
BIT
NAME
2
En_EOC
FUNCTION
Enables the End Of Charge current
level threshold detection. When set
to '0' the EOC is disabled.
The End Of Charge current threshold default setting is at
0.1C. This EOC value is set relative to C the set full rate constant current. This threshold can be set to 0.1C, 0.15C, 0.2C
or 0.25C bychanging the contents of the PROG_EOC[1:0]
register bits.
TABLE 11. Register Address 8h'12: CHGCNTL3
BIT
NAME
2
Prog_EOC[0]
3
Prog_EOC[1]
FUNCTION
Set the End Of Charge Current.
See Table 9
LDO Mode on device option LP3918TL-L
The charger circuit automatically enters an LDO mode if no
battery is detected on insertion of the charger input voltage.
In LDO mode the battery pin is regulated to 4.2V and can
source up to 1.0A of current. Normal operation with a battery
connected can be re-established via the serial interface. The
serial interface allows the device to switch between modes as
required however care is required to ensure that LDO mode
is not initiated while a battery is present.
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LP3918
TERMINATION AND RESTART
The termination and restart voltage levels are determined by
the data in the VTERM[1:0] and PROG_VSTRT[1:0] bits in
the control register. The restart voltage is programmed relative to the selected termination voltage.
The Termination voltages available are 4.1V, 4.2V (default),
4.3V, and 4.4V.
The Restart voltages are determined relative to the termination voltage level and may be set to 50mV, 100mV, 150mV
(default), and 200mV below the set termination voltage level.
CHARGER FULL RATE CURRENT
Programming Information
TABLE 12. Register Address 8h'11: CHGCNTL2
Data BITs
HEX
NAME
000[00000]
00
Prog_ICHG
FUNCTION
000[00001]
01
100mA
000[00010]
02
150mA
000[00011]
03
200mA
000[00100]
04
250mA
000[00101]
05
300mA
000[00110]
06
350mA
BIT
NAME
000[00111]
07
400mA
4
VTERM[0]
000[01000]
08
450mA
5
VTERM[1]
000[01001]
09
500mA
000[01010]
0A
550mA
000[01011]
0B
600mA
000[01100]
0C
650mA
000[01101]
0D
700mA
000[01110]
0E
750mA
000[01111]
0F
800mA
000[10000]
10
850mA
000[10001]
11
900mA
000[10010]
12
950mA
50mA
Programming Information
TABLE 13. Register Address 8h'12: CHGCNTL3
Set the charging termination
voltage.
See Table 6
TABLE 14. Register Address 8h'12: CHGCNTL3
BIT
NAME
0
VRSTRT[0]
1
VRSTRT[1]
Charger Operation
The operation of the charger with EOC enabled is shown in this simplified flow diagram.
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FUNCTION
20
FUNCTION
Set the charging restart voltage.
See Table 8
LP3918
20211636
FIGURE 2. Simplified Charger Functional Flow Diagram (EOC is enabled)
The charger operation may be depicted by the following graphical representation of the voltage and current profiles.
20211635
FIGURE 3. Charge Cycle Diagram
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LP3918
Further Charger Register Information
Charger Control Register 1
TABLE 16. Register Address 8h'13: CHGSTATUS1
TABLE 15. Register Address 8h'10: CHGCNTL1
BIT
NAME
7
USB_MODE
_EN
Sets the Current Level in USB
mode.
6
CHG_MODE
_EN
Forces the charger into USB mode
when active high.
If low, charger is in normal charge
mode.
5
4
3
2
1
0
Forces an EOC event.
TOUT_
Doubling
Doubles the timeout delays for all
timeout signals.
EN_Tout
Enables the timeout counters.
When set to '0' the timeout
counters are disabled.
Enables the End of Charge current
level threshold detection. When set
to '0' the functions are disabled.
Set_
LDOmode
Forces the charger into LDO mode.
Function available on
LP3918TL_L.
EN_CHG
Charger enable.
FUNCTION (if bit = '1')
7
BAT_OVER
_OUT
6
CHGIN_
OK_Out
Is set when a valid input voltage is
detected at CHG_IN pin.
5
EOC
Is set when the charging current
decreases below the programmed
End Of Charge levlel.
4
Tout_
Fullrate
3
Tout_
Precharge
Set after timeout for precharge
mode.
2
LDO_Mode
Only available on LP3918TL_L.
1
Fullrate
Set when the charger is in CC/CV
mode.
0
PRECHG
Is set when battery voltage
exceeds 4.7V.
Set after timeout on full rate
charge.
Set during precharge.
Charger Status Register 2 Read only
TABLE 17. Register Address 8h'13: CHGSTATUS2
Charger Status Register 1 Read only
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NAME
FUNCTION (if bit = '1')
FORCE
_EOC
EN_EOC
BIT
22
BIT
NAME
FUNCTION (if bit = '1')
1
Tout_
ConstV
Set after timeout in CV phase.
0
BAD_
BATT
Set at bad battery state.
LDO OUTPUT PROGRAMMING
TABLE 19.
20211611
FIGURE 4. IMON Voltage vs Charge Current
Regi
ster
Add
(hex)
NAME
Data Range
(hex)
Output Voltage
01
LDO1PGM
O/P
03 - 0F
1.5V to 3.3V
(def. 1.8V)
02
LDO2PGM
O/P
00 - 0F
2.5V to 3.3V
(def 3.0V)
03
LDO3PGM
O/P
05 - 0C
2.7V to 3.05V
(def 3.0V)
04
LDO4PGM
O/P
00 - 0F
1.5V to 3.3V
(def 3.0V)
05
LDO5PGM
O/P
05 - 0C
2.7V to 3.05V
(def 3.0V)
06
LDO6PGM
O/P
05 - 0C
2.7V to 3.05V
(def 3.0V)
07
LDO7PGM
O/P
00 - 0F
1.5V to 3.3V
(def 3.0V)
See Table 2 for full programmable range of values.
Note that this function is not available if there is no input at
CHG_IN or if the charger is off due to the input at CHG_IN
being outwith the operating voltage range.
EXTERNAL CAPACITORS
The Low Drop Out Linear Voltage regulators on the LP3918
require external capacitors to ensure stable outputs. The
LDO's on the LP3918 are specifically designed to use small
surface mount ceramic capacitors which require minimum
board space. These capacitors must be correctly selected for
good performance
LDO Information
OPERATIONAL INFORMATION
The LP3918 has 7 LDO's of which 3 are enabled by default,
LDO's 1,2 and 3 are powered up during the power up sequence. LDO4, 5 and 6 are separately, externally enabled
and will follow LDO2 in start up if their respective enable pin
is pulled high. LDO2, LDO3 and LDO7 can be enabled/disabled via the serial interface.
LDO2 must remain in regulation otherwise the device will
power down. While LDO1 is enabled this must also be in regulation for the device to remain powered. If LDO1 is disabled
via I2C interface the device will not shut down.
INPUT CAPACITOR
Input capacitors are required for correct operation. It is recommended that a 10µF capacitor be connected between
each of the voltage input pins and ground (this capacitance
value may be increased without limit). This capacitor must be
located a distance of not more than 1cm from the input pin
and returned to a clean analogue ground. A ceramic capacitor
is recommended although a good quality tantalum or film capacitor may be used at the input.
Important: Tantalum capacitors can suffer catastrophic failures due to surge current when connected to a lowimpedance source of power (like a battery or a very large
capacitor). If a tantalum capacitor is used at the input, it must
be guaranteed by the manufacturer to have surge current rating sufficent for the application. There are no requirements for
the ESR (Equivalent Series Resistance) on the input capacitor, but tolerance and temparature coefficient must be considered when selecting the capacitor to ensure the capacitance will remain within its operational range over the entire
operating temperature range and conditions.
INPUT VOLTAGES
There are two input voltage pins used to power the 7LDO's
on the LP3918. VIN2is the supply for LDO3, LDO4, LDO5,
LDO6 and LDO7. VIN1is the supply for LDO1 and LDO2.
These input voltages should be tied to the Batt pin in the
application.
PROGRAMMING INFORMATION
Enable via Serial Interface
TABLE 18. Register Address 8h'00: OP_EN
BIT
NAME
0
LDO1_EN
2
LDO3_EN
3
LDO7_EN
FUNCTION
Output Capacitor
Bit set to '0' - LDO disabled
Bit set to '1' - LDO enabled
Correct selection of the output capacitor is critical to ensure
stable operation in the intended application.The output capacitor must meet all the requirements specified in the recommended capacitor table over all conditions in the application. These conditions include DC-bias, frequency and
temperature. Unstable operation will result if the capacitance
23
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LP3918
Note that the default setting for this Register is [0000 0101].
This shows that LDO1 and 3 are enabled by default whereas
LDO7 is not enabled by default on start up.
IMON CHARGE CURRENT MONITOR
Charge current is monitored within the charger section and a
proportional voltage representation of the charge current is
presented at the IMON output pin. The output voltage relationship to the actual charge current is represented in the
following graph and by the equation:
VIMON(mV) = (2.47 x ICHG)(mA)
LP3918
As an example Figure 5 shows a typical graph showing a
comparison of capacitor case sizes in a Capacitance vs DC
Bias plot. As shown in the graph, as a result of DC Bias condition the capacitance value may drop below minimum capacitance value given in the recommended capacitor table
(0.7µF in this case). Note that the graph shows the capacitance out of spec for 0402 case size capacitor at higher bias
voltages. It is therefore recommended that the capacitor manufacturers specifications for the nominal value capacitor are
consulted for all conditions as some capacitor sizes (e.g
0402) may not be suitable in the actual application. Ceramic
capacitors have the lowest ESR values, thus making them
best for eliminating high frequency noise. The ESR of a typical
1µF ceramic capacitor is in the range of 20mΩ to 40mΩ, and
also meets the ESR requirements for stability. The temperature performance of ceramic capacitors varies by type. Capacitor type X7R is specified with a tolerance of ±15% over
temperature range -55ºC to +125ºC. The X5R has similar tolerance over the reduced temperature range -55ºC to +85ºC.
Most large value ceramic capacitors (<2.2µF) are manufactured with Z5U or Y5V temperature characteristics, which
results in the capacitance dropping by more than 50% as the
temperature goes from 25ºC to 85ºC. Therefore X7R is recommended over these other capacitor types in applications
where the temperature will change significally above or below
25ºC.
drops below the minimum specified value. The LP3918 is designed specifically to work with very small ceramic output
capacitors. The LDO's on the LP3918 are specifically designed to be used with X7R and X5R type capacitors. With
these capacitors selection of the capacitor for the application
is dependant on the range of operating conditions and temperature range for that application. (See section on Capacitor
Characteristics). It is also recommended that the output capacitor be placed within 1cm from the output pin and returned
to a clean ground line.
Capacitor Characteristics
The LDO's on the LP3918 are designed to work with ceramic
capacitors on the input and output to take advantage of the
benifits they offer. For capacitance values around 1µF, ceramic capacitors give the circuit designer the best design
options in terms of low cost and minimal area. For both input
and output capacitors careful interpretation of the capacitor
specification is required to ensure correct device operation.
The capacitor value can change greatly dependant on the
conditions of operation and capacitor type. In particular to ensure stability, the output capacitor selection should take account of all the capacitor parameters to ensure that the
specification is met within the application. Capacitance value
can vary with DC bias conditions as well as temperature and
frequency of operation. Capacitor values will also show some
decrease over time due to aging. The capacitor parameters
are also dependant on the particular case size with smaller
sizes giving poorer performance figures in general.
20211612
FIGURE 5. Graph Showing A Typical Variation in
Capacitance vs DC Bias
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24
LP3918
No-Load Stability
The LDO's on the LP3918 will remain stable in regulation with
no external load.
TABLE 20. LDO Output Capacitors Recommended Specification
Symbol
Parameter
Capacitor Type
Typ
Limit
Min
Max
Units
Co(LDO1)
Capacitance
X5R. X74
1.0
0.7
2.2
µF
Co(LDO2)
Capacitance
X5R. X74
1.0
0.7
2.2
µF
Co(LDO3)
Capacitance
X5R. X74
1.0
0.7
2.2
µF
Co(LDO4)
Capacitance
X5R. X74
1.0
0.7
2.2
µF
Co(LDO5)
Capacitance
X5R. X74
1.0
0.7
2.2
µF
Co(LDO6)
Capacitance
X5R. X74
1.0
0.7
2.2
µF
Co(LDO7)
Capacitance
X5R. X74
1.0
0.7
2.2
µF
Note: The capacitor tolerance should be 30% or better over
the full temperature range. X7R or X5R capacitors should be
used. These specifications are given to ensure that the capacitance remains within these values over all conditions
within the application. See Capacitor Characteristics section
in Application Information.
MISC CONTROL REGISTER
TABLE 22. Register Address 8h'1C: Misc
BIT
NAME
1
APU_TSD
_EN
0
PWR_HOLD
DELAY
Thermal Shutdown
The LP3918 has internal limiting for high on-chip temperatures caused by high power dissipation etc. This Thermal
Shutdown, TSD, function monitors the temperature with respect to a threshold and results in a device power-down.
If the threshold of +160°C has been exceeded then the device
will power down. Recovery from this TSD event can only be
initiated after the chip has cooled below +115°C. This device
recovery is controlled by the APU_TSD_EN bit (bit 1) in control register MISC, 8h'1C. See Table 22 If the APU_TSD_EN
is set low then the device will shutdown requiring a new start
up event initiated by PWR_ON, HF_PWR, or CHG_IN. If
APU_TSD_EN is set high then the device will power up automatically when the shutdown condition clears. In this case
the control register settings are preserved for the device
restart.
The threshold temperature for the device to clear this TSD
event is 115°C. This threshold applies for any start up thus
the device temperature must be below this threshold to allow
a start up event to initiate power up.
INTERFACE BUS OVERVIEW
The I2C compatible synchronous serial interface provides access to the programmable functions and registers on the
device.
This protocol uses a two-wire interface for bi-directional communications between the IC’s connected to the bus. The two
interface lines are the Serial Data Line (SDA), and the Serial
Clock Line (SCL). These lines should be connected to a positive supply, via a pull-up resistor of 1.5KΩ, and remain HIGH
even when the bus is idle.
Every device on the bus is assigned a unique address and
acts as either a Master or a Slave depending on whether it
generates or receives the serial clock (SCL).
TABLE 21. Register Address 8h'0C: Status
NAME
PWR_ON
_TRIG
PMU start up is initiated by
PWR_ON.
6
HF_PWR
_TRIG
PMU start up is initiated by
HF_PWR.
5
CHG_IN
_TRIG
PMU start up is initiated by
CHG_IN.
1b'0: If PWR_HOLD is low for 35ms
the device will shutdown. (Default)
1b'1: If PWR_HOLD is low for
350ms the device will shutdown.
I2C Compatible Serial Bus Interface
STATUS REGISTER READ ONLY
7
1b' 0: Device will shutdown
completely if thermal shutdown
occurs. Requires a new start up
event to restart the PMU.
1b'1: Device will start up
automatically after thermal
shutdown condition is removed.
(Device tries to keep its internal
state.)
Bits <7..2> are not used.
Further Register Information
BIT
FUNCTION (if bit = '1')
FUNCTION (if bit = '1')
DATA TRANSACTIONS
One data bit is transferred during each clock pulse. Data is
sampled during the high state of the serial clock (SCL). Consequently, throughout the clock’s high period, the data should
remain stable. Any changes on the SDA line during the high
state of the SCL and in the middle of a transaction, aborts the
current transaction. New data should be sent during the low
SCL state. This protocol permits a single data line to transfer
both command/control information and data using the synchronous serial clock.
Bits <4..0> are not used.
25
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LP3918
20211610
FIGURE 7. Start and Stop Conditions
20211613
In addition to the first Start Condition, a repeated Start Condition can be generated in the middle of a transaction. This
allows another device to be accessed, or a register read cycle.
FIGURE 6. Bit Transfer
Each data transaction is composed of a Start Condition, a
number of byte transfers (set by the software) and a Stop
Condition to terminate the transaction. Every byte written to
the SDA bus must be 8 bits long and is transferred with the
most significant bit first. After each byte, an Acknowledge signal must follow. The following sections provide further details
of this process.
ACKNOWLEDGE CYCLE
The Acknowledge Cycle consists of two signals: the acknowledge clock pulse the master sends with each byte transferred,
and the acknowledge signal sent by the receiving device.
The master generates the acknowledge clock pulse on the
ninth clock pulse of the byte transfer. The transmitter releases
the SDA line (permits it to go high) to allow the receiver to
send the acknowledge signal. The receiver must pull down
the SDA line during the acknowledge clock pulse and ensure
that SDA remains low during the high period of the clock
pulse, thus signaling the correct reception of the last data byte
and its readiness to receive the next byte.
START AND STOP
The Master device on the bus always generates the Start and
Stop Conditions (control codes). After a Start Condition is
generated, the bus is considered busy and it retains this status until a certain time after a Stop Condition is generated. A
high-to-low transition of the data line (SDA) while the clock
(SCL) is high indicates a Start Condition. A low-to-high transition of the SDA line while the SCL is high indicates a Stop
Condition.
20211628
FIGURE 8. Bus Acknowledge Cycle
“ACKNOWLEDGE AFTER EVERY BYTE” RULE
The master generates an acknowledge clock pulse after each
byte transfer. The receiver sends an acknowledge signal after
every byte received.
There is one exception to the “acknowledge after every byte”
rule.
When the master is the receiver, it must indicate to the transmitter an end of data by not-acknowledging (“negative acknowledge”) the last byte clocked out of the slave. This
“negative acknowledge” still includes the acknowledge clock
pulse (generated by the master), but the SDA line is not pulled
down.
(binary 1111110). Before any data is transmitted, the master
transmits the address of the slave being addressed. The slave
device should send an acknowledge signal on the SDA line,
once it recognizes its address.
The slave address is the first seven bits after a Start Condition. The direction of the data transfer (R/W) depends on the
bit sent after the slave address — the eighth bit.
When the slave address is sent, each device in the system
compares this slave address with its own. If there is a match,
the device considers itself addressed and sends an acknowledge signal. Depending upon the state of the R/W bit (1:read,
0:write), the device acts as a transmitter or a receiver.
ADDRESSING TRANSFER FORMATS
Each device on the bus has a unique slave address. The
LP3918 operates as a slave device with the address 7h’7E
CONTROL REGISTER WRITE CYCLE
• Master device generates start condition.
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26
•
•
•
•
•
•
•
•
•
Master device sends slave address (7 bits) and the data
direction bit (r/w = “0”).
Slave device sends acknowledge signal if the slave
address is correct.
Master sends control register address (8 bits).
Slave sends acknowledge signal.
Master sends data byte to be written to the addressed
register.
Slave sends acknowledge signal.
If master will send further data bytes the control register
address will be incremented by one after acknowledge
signal.
Write cycle ends when the master creates stop condition.
•
CONTROL REGISTER READ CYCLE
• Master device generates a start condition.
• Master device sends slave address (7 bits) and the data
direction bit (r/w = “0”).
• Slave device sends acknowledge signal if the slave
address is correct.
• Master sends control register address (8 bits).
• Slave sends acknowledge signal.
• Master device generates repeated start condition.
• Master sends the slave address (7 bits) and the data
direction bit (r/w = “1”).
• Slave sends acknowledge signal if the slave address is
correct.
Slave sends data byte from addressed register.
If the master device sends acknowledge signal, the control
register address will be incremented by one. Slave device
sends data byte from addressed register.
Read cycle ends when the master does not generate
acknowledge signal after data byte and generates stop
condition.
Address Mode
Data Read
<Start Condition>
<Slave Address><r/w = ‘0’>[Ack]
<Register Addr.>[Ack]
<Repeated Start Condition>
<Slave Address><r/w = ‘1’>[Ack]
[Register Date]<Ack or nAck>
… additional reads from subsequent register
address possible
<Stop Condition>
Data Write
<Start Condition>
<Slave Address><r/w = ‘0’>[Ack]
<Register Addr.>[Ack]
<Register Data>[Ack]
… additional writes to subsequent register
address possible
<Stop Condition>
< > Data from master [ ] Data from slave
REGISTER READ AND WRITE DETAIL
20211629
FIGURE 9. Register Write Format
27
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LP3918
•
LP3918
20211630
FIGURE 10. Register Read Format
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28
LP3918
Physical Dimensions inches (millimeters) unless otherwise noted
Thin micro-SMD25 Package
NS Package Number MKT-TLA2511A
X1 = 2.465mm ± 0.030mm
X2 = 2.465mm ± 0.030mm
X3 = 0.600mm ± 0.075mm
29
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LP3918 Battery Charge Management and Regulator Unit
Notes
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