LTC4015
Multichemistry Buck Battery
Charger Controller with Digital Telemetry System
FEATURES
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DESCRIPTION
The
LTC
®
4015
is a complete synchronous buck controller/
charger with pin selectable, chemistry specific charging
and termination algorithms.
The LTC4015 can charge Li-Ion/Polymer, LiFePO
4
, or lead-
acid batteries. Battery charge voltage is pin selectable and
I
2
C adjustable. Input current limit and charge current can
be accurately programmed with sense resistors and can
be individually adjusted via the I
2
C serial port. A digital
telemetry system monitors all system power parameters.
Safety timer and current termination algorithms are sup-
ported for lithium chemistry batteries. The LTC4015 also
includes automatic recharge, precharge (Li-Ion) and NTC
thermistor protection. The LTC4015's I
2
C port allows user
customization of charger algorithms, reading of charger
status information, configuration of the maskable and
programmable alerts, plus use and configuration of the
Coulomb counter.
Available in a 38-Lead 5mm × 7mm QFN package.
L,
LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and
PowerPath is a trademark of Linear Technology Corporation. All other trademarks are the
property of their respective owners.
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Multichemistry Li-Ion/Polymer, LiFePO
4
, or Lead-
Acid Battery Charger with Termination
High Efficiency Synchronous Buck Battery Charger
Digital Telemetry System Monitors V
BAT
, I
BAT
,
R
BAT
,NTC Ratio (Battery Temperature), V
IN
, I
IN
,
V
SYSTEM
, Die Temperature
Coulomb Counter and Integrated 14-Bit ADC
Wide Charging Input Voltage Range: 4.5V to 35V
Wide Battery Voltage Range: Up to 35V
Input Undervoltage Charge Current Limit Loop
Maximum Power Point Tracking
Optional I
2
C Serial Port Control
Input Current Limit Prioritizes System Load Output
Input and Output Ideal Diodes Provide Low Loss
PowerPath™ Operation
Instant-On Operation with Discharged Battery
APPLICATIONS
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Portable Medical Instruments/Military Equipment
Industrial Handhelds/Lighting
Ruggedized Notebook/Tablet Computers
TYPICAL APPLICATION
12V
IN
2-Cell Li-Ion 8A Step-Down Battery Charger Controller
V
IN
12V
R
SNSI
SYS
Step-Down Charger Efficiency and
Coulomb Counter Error vs
Battery Charge Current
100
0.5
COULOMB COUNTER ERROR (%)
95
90
EFFICIENCY (%)
85
80
75
70
65
60
55
50
0.1
1
CHARGE CURRENT (A)
–2.0
10
4015 TA01b
V
IN
INFET
CLP
CLN SYS SYSM5
OUTFET
INTV
CC
DRV
CC
BOOST
TG
UVCLFB
SMBALERT
µCONTROLLER
DV
CC
SCL
SDA
CELLS0
INTV
CC
CELLS1
CELLS2
CHEM0
CHEM1
RT
V
C
CCREFP
CCREFM
EQ
SGND
(PADDLE)
GND
LTC4015
0.0
–0.5
–1.0
EFFICIENCY
QC ERROR
–1.5
SW
BG
2P5V
CC
CSPM5
CSP
CSN
BATSENS
NTCBIAS
R
NTCBIAS
MPPT
MPPT
ENABLE
NTC
T
2-CELL Li-Ion
BATTERY
PACK
R
NTC
4015 TA01a
R
SNSB
LEAD-ACID
EQUALIZE
CHARGE
4015fa
For more information
www.linear.com/LTC4015
1
LTC4015
TABLE OF CONTENTS
Features ............................................................................................................................ 1
Applications ....................................................................................................................... 1
Typical Application ............................................................................................................... 1
Description......................................................................................................................... 1
Absolute Maximum Ratings ..................................................................................................... 3
Order Information ................................................................................................................. 3
Data Sheet Conventions ......................................................................................................... 3
Pin Configuration ................................................................................................................. 3
Electrical Characteristics ........................................................................................................ 4
Typical Performance Characteristics .........................................................................................10
Pin Functions .....................................................................................................................13
Block Diagram....................................................................................................................15
I
2
C Write Protocol ...............................................................................................................16
I
2
C Read Protocol ................................................................................................................16
Timing Diagram ..................................................................................................................16
Operation..........................................................................................................................17
Applications Information .......................................................................................................43
Register Description ............................................................................................................50
DETAILED Register Descriptions ..............................................................................................56
Typical Applications .............................................................................................................73
Package Description ............................................................................................................74
Revision History .................................................................................................................75
Typical Application ..............................................................................................................76
Related Parts .....................................................................................................................76
4015fa
2
For more information
www.linear.com/LTC4015
LTC4015
ABSOLUTE MAXIMUM RATINGS
(Notes 1, 5)
PIN CONFIGURATION
TOP VIEW
CELLS0
CHEM1
CHEM0
INFET
CLN
31 SYS
30 SYSM5
29 OUTFET
28 INTV
CC
27 DRV
CC
39
GND
26 BG
25 BOOST
24 TG
23 SW
22 2P5V
CC
21 MPPT
20 CSP
13 14 15 16 17 18 19
EQ
GND
CCREFM
CCREFP
BATSENS
CSPM5
CSN
CLP
V
IN
V
IN
, CSN..................................................... –0.3V to 40V
BOOST to SW.............................................. –0.3 to 5.5V
BATSENS to CSN, CSP to CSN, CLP to CLN, CLP, CLN
to SYS................................................................±0.3V
DV
CC
, DRV
CC
............................................. –0.3V to 5.5V
CELLSO, CELLS1, CELLS2, CHEM0, CHEM1,
MPPT, EQ.......................................... –0.3V to INTV
CC
SDA, SCL,
SMBALERT
.............................. –0.3V to DV
CC
I
UVCLFB
(Note 4) ..................................................±200µA
INTV
CC
Peak Output Current ................................100mA
Operating Junction Temperature Range
(Notes 2,3) ............................................. –40 to 125°C
Storage Temperature Range ......................–65 to 150°C
38 37 36 35 34 33 32
CELLS1 1
CELLS2 2
DV
CC
3
SCL 4
SDA 5
SMBALERT
6
SGND 7
UVCLFB 8
V
C
9
RT 10
NTC 11
NTCBIAS 12
UHF PACKAGE
38-LEAD (5mm
×
7mm) PLASTIC QFN
T
JMAX
= 125°C,
θ
JA
= 34°C/W (NOTE 1)
EXPOSED PAD (PIN 39) IS GND, MUST BE SOLDERED TO PCB GND
ORDER INFORMATION
LEAD FREE FINISH
LTC4015EUHF#PBF
LTC4015IUHF#PBF
TAPE AND REEL
(http://www.linear.com/product/LTC4015#orderinfo)
PART MARKING*
4015
4015
PACKAGE DESCRIPTION
38-Lead (5mm
×
7mm) Plastic QFN
38-Lead (5mm
×
7mm) Plastic QFN
TEMPERATURE RANGE
–40°C to 125°C
–40°C to 125°C
LTC4015EUHF#TRPBF
LTC4015IUHF#TRPBF
Consult LTC Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container.
For more information on lead free part marking, go to:
http://www.linear.com/leadfree/
For more information on tape and reel specifications, go to:
http://www.linear.com/tapeandreel/.
Some packages are available in 500 unit reels through
designated sales channels with #TRMPBF suffix.
DATA SHEET CONVENTIONS
• V
PINNAME
and I
PINNAME
represents the voltage on a pin
or the pin current; V
EQ
= EQ Pin Voltage.
• Hexadecimal numbers are prefixed with 0x; 0x10 is a
hexadecimal 10
• Register symbol names will be capitalized. Symbols
within a register will be lower case;
en_meas_sys_valid_alert is bit 15 in register
EN_LIMIT_ALERTS (0x0D)
• LiFePO
4
is lithium iron phosphate, Li-Ion is used for
both lithium-ion and lithium-ion polymer
• Lithium chemistries refers to LiFePO
4
, lithium-ion, and
lithium-ion polymer as a group.
• When a register name is used in square brackets, this
means the 16 bit value associated with that register;
For example [VBAT] is the 16 bit ADC measurement
value of the per cell battery voltage.
4015fa
For more information
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3
LTC4015
The
l
denotes the specifications which apply over the specified operating
junction temperature range, otherwise specifications are at T
A
= 25°C. (Note 2), DV
CC
= 3.3V, UVCLFB = 1.5; CELLS1 = INTV
CC
; EQ,
MPPT, CELLS0, CELLS2, CHEM0, CHEM1 = 0; RT = 95.3k; R
CCREF
= 301k, R
NTCBIAS
= R
NTC
= 10k; BATSENS = CSN = CSP; DRV
CC
= INTV
CC
;
SYS = CLP = CLN. Conditions: Charging; V
IN
= 12V, SYS = 12V, BATSENS = 7.4V …..Battery Only; V
IN
= 0V, SYS = 8.4V, BATSENS = 8.4V
SYMBOL
V
IN
V
BAT
V
CHARGE(TOL)
PARAMETER
Input Supply Voltage Range
Battery Voltage Range
CONDITIONS
Note 8
Note 8
l
l
l
l
l
ELECTRICAL CHARACTERISTICS
MIN
3.1
–1.25
–2.0
3.05
TYP
MAX
35
35
1.25
2.0
35
UNITS
V
V
%
%
V
µA
µA
mA
mA
mA
Charge Voltage, Regulated Battery per Cell Li-Ion ,4.2V per Cell; LiFePO
4
3.6V per
Tolerance, All Chemistries
Cell; Lead-Acid 2.2V per Cell
Regulated Battery Charge Current
Tolerance
Full-Scale V
CSP–CSN
/R
SNSB
Note 8
Battery Only, Telemetry Inactive
Battery Only, Telemetry Active 1% Duty
Cycle
Battery Only, Telemetry Active
Continuously
I
Q
, Charging
I
Q
, Ship Mode
Charging, Switcher Suspended
Charging, V
BAT
> V
CHARGE
(Note 7)
Ship Mode (V
IN
= 0)
Battery Only (No Input Supply)
Charging
Battery Only, Telemetry Off
Battery Only, Telemetry On
Charging, V
BAT
> V
CHARGE
(Note 7)
V
SYS
SYS Pin Voltage
Battery Discharge Current (No Input
Supply, Coulomb Counter Disabled)
Quiescent Current I
Q
= I
VIN
+ I
CLP
+ I
CLN
+ I
SYS
+ I
SW
+ I
CSP
+ I
CSN
+ I
BATSENS
l
l
112
140
2.84
3.00
4.10
325
364
l
5
–200
<140
100
2.75
3.65
40
200
µA
nA
µA
µA
mA
mA
I
Vin
I
SYS
V
IN
Pin Current
SYS Pin Current
V
IN_DUVLO
V
IN_OVLO
V
IN
to V
BATSENS
Differential Undervoltage
(Must Be Satisfied for Charging)
Input Overvoltage Lockout
(Inhibits Charger)
UVCLFB Pin Regulation Range
(8-Bit DAC)
UVCLFB Pin Regulation DAC LSB
UVCLFB Pin Leakage Current
Rising Threshold
Hysteresis
Rising Threshold
Hysteresis
V
UVCLFB
Maximum Code 0xFF
V
UVCLFB
Minimum Code 0x00
V
UVCLFB
= 1.2V
Full-Scale V
CLP–CLN
/R
SNSI
I
CL
= (V
CLP – CLN
)/R
SNSI
V
CLP
= 12V, V
CLP–CLN
= 32mV
V
CLP
= 12V, V
CLP–CLN
= 32mV
Note 8
l
l
140
37.7
200
100
38.6
1.4
1200
4.6875
4.6875
250
39.5
mV
mV
V
V
mV
mV
mV
nA
%
mV/R
SNSI
mV/R
SNSI
µA
Input Undervoltage Current Limit
V
UVCLFB
l
1188
1212
l
–100
–2.0
0.5 – 32
0.5
45
–100
4
100
2.0
Input Current Limit
Regulated Input Current Limit Tolerance
I
CL
Input Current Limit Range
Input Current Limit LSB Step Size
CLP Input Current
CLN Input Current
CLP, CLN Common Mode Range
l
100
35
nA
V
4015fa
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For more information
www.linear.com/LTC4015
LTC4015
The
l
denotes the specifications which apply over the specified operating
junction temperature range, otherwise specifications are at T
A
= 25°C. (Note 2), DV
CC
= 3.3V, UVCLFB = 1.5; CELLS1 = INTV
CC
; EQ,
MPPT, CELLS0, CELLS2, CHEM0, CHEM1 = 0; RT = 95.3k; R
CCREF
= 301k, R
NTCBIAS
= R
NTC
= 10k; BATSENS = CSN = CSP; DRV
CC
= INTV
CC
;
SYS = CLP = CLN. Conditions: Charging; V
IN
= 12V, SYS = 12V, BATSENS = 7.4V …..Battery Only; V
IN
= 0V, SYS = 8.4V, BATSENS = 8.4V
SYMBOL
V
INTVCC
V
INTVCC_CUVLO
V
INTVCC_TUVLO
PARAMETER
Internal Regulator Output Voltage
Load Regulation
INTV
CC
Undervoltage Charger Lockout
INTV
CC
Undervoltage Telemetry System
Lockout
DRV
CC
Supply Voltage
DRV
CC
Undervoltage Lockout
Battery Charger
(All Chemistries)
I
CHARGE
Battery Charge Current Range,
Battery Charge Current Resolution
Peak Low V
CSP
Charge Current
I
BATSENS
+ I
CSP
+ I
CSN
Lithium-Ion/Lithium Polymer Battery Charger
Lithium-Ion/Lithium Polymer Programmable, CHEM1, CHEM0 = [LL] (Note 9)
Li-Ion Charge Voltage Max DAC Setting
Li-Ion Charge Voltage Min DAC Setting
Li-Ion Charge Voltage DAC LSB
Li-Ion Recharge Voltage
Charge C/x Termination Setting
4.2V Fixed Li-Ion Charge Voltage
4.2V Fixed Li-Ion Recharge Voltage
4.1V Fixed Li-Ion Charge Voltage
4.1V Fixed Li-Ion Recharge Voltage
4.0V Fixed Li-Ion Charge Voltage
4.0V Fixed Li-Ion Recharge Voltage
Low Battery Precharge Threshold
Low Battery Precharge Hysteresis
Low Battery Precharge Current
Max Charge Time
Charge Termination Timer
(Default Termination)
Percent of Charge Voltage
V
CSP–CSN
(I
2
C Termination Option)
CHEM1,0 = [H,H] (Note 11)
CHEM1,0 = [H,H]
CHEM1,0 = [L,Z] (Note 11)
CHEM1,0 = [L,Z]
CHEM1,0 = [Z,L] (Note 11)
CHEM1,0 = [Z,L]
Charge Voltage = 4.2V
Charge Voltage = 4.2V
I
CHARGE
Set to 32 mV/R
SNSB
Code 11111 (Note 11)
Code 00000 (Note 11)
4.2
3.8125
12.5
97.5
3.2
4.200
4.095
4.100
4.000
4.000
3.900
2.85
50
3
18.2
4
V/Cell
V/Cell
mV
%
mV
V/Cell
V/Cell
V/Cell
V/Cell
V/Cell
V/Cell
V/Cell
mV/Cell
mV/R
SNSB
hrs
hrs
V
CSP
> 2.6V (Note 10)
V
CSP
< 2.4V
Charger Suspended (Telemetry Active)
V
IN
, V
SYS
= 12V, V
BATSENS
= 7.4V
V
IN
, V
SYS
= 35V, V
BATSENS
= 34V (9 Cells)
1 – 32
1
7.0
110
200
mV/R
SNSB
mV/R
SNSB
mV/R
SNSB
µA
µA
Rising Threshold
Hysteresis
l
ELECTRICAL CHARACTERISTICS
CONDITIONS
No Load
I
INTVCC
= 50 mA
Rising Threshold
Hysteresis
Rising Threshold
Hysteresis
l
l
MIN
TYP
5
1.5
MAX
UNITS
V
INTV
CC
Regulator (SYS is Supply Pin for This Regulator)
2.5
4.4
2.95
%
V
V
V
V
V
V
V
4.2
2.75
4.3
0.3
2.85
0.12
DRV
CC
INPUT (External Supply or Supplied by INTV
CC
)
V
DRVCC
4.3
4.1
4.2
0.3
5.5
4.3
Lithium-Ion/Lithium Polymer Fixed 4.2, 4.1, 4.0 Charge Voltage, CHEM1, CHEM0 = [HH,LZ,ZL] (Note 9)
Lithium-Ion/Lithium Polymer, CHEM1, CHEM0 = [LL, HH, LZ, ZL] (Note 9)
4015fa
For more information
www.linear.com/LTC4015
5