LTC4100
Smart Battery
Charger Controller
FEATURES
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DESCRIPTIO
July 2003
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Single Chip Smart Battery Charger Controller
100% Compliant (Rev. 1.1) SMBus Support allows
for Operation with or without Host
SMBus Accelerator Improves SMBus Timing*
Wide Output Voltage Range: 6.4V to 26V
Hardware Interrupt and SMBAlert Response
Eliminate Interrupt Polling
High Efficiency Synchronous Buck Charger
0.5V Dropout Voltage; Maximum Duty Cycle > 98%
AC Adapter Current Limit Maximizes Charge Rate
±0.8%
Voltage Accuracy;
±5%
Current Accuracy
Up to 4A Charging Current Capability
10-Bit DAC for Charge Current Programming
11-Bit DAC for Charger Voltage Programming
User-Selectable Overvoltage and Overcurrent Limits
High Noise Immunity SafetySignal Sensor
Small 24-Pin Narrow (0.209") SSOP Package
The LTC
®
4100 Smart Battery Charger is a single chip
charging solution that dramatically simplifies construc-
tion of an SBS compliant system. The LTC4100 imple-
ments a Level 2 charger function whereby the charger can
be programmed by the battery or by the host. A SafetySignal
on the battery being charged is monitored for tempera-
ture, connectivity and battery type information. The SMBus
interface remains alive when the AC power adapter is
removed and responds to all SMBus activity directed to
it, including SafetySignal status (via the ChargerStatus
command). The charger also provides an interrupt to the
host whenever a status change is detected (e.g., battery
removal, AC adapter connection).
Charging current and voltage are restricted to chemistry
specific limits for improved system safety and reliability.
Limits are programmable by two external resistors. Addi-
tionally, the maximum average current from the AC adapter
is programmable to avoid overloading the adapter when
simultaneously supplying load current and charging
current. When supplying system load current, charging
current is automatically reduced to prevent adapter over-
load.**
APPLICATIO S
s
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Portable Instruments and Computers
Data Storage Systems and Battery Backup Servers
, LTC and LT are registered trademarks of Linear Technology Corporation.
*U.S. Patent No. 6,650,174 **U.S. Patent No. 5,723,970
TYPICAL APPLICATIO
DCIN
3V
TO 5.5V
13.7k
1.21k
17
11
CHGEN
ACP
6
10
7
9
8
15
16
13
1.13k
10k
54.9k
0.082µF
14
20
LTC4100
V
DD
DCDIV
CHGEN
ACP
SMBALERT
SCL
SDA
THB
THA
I
LIM
V
LIM
I
DC
0.1µF
DCIN
INFET
CLP
CLN
TGATE
BGATE
PGND
CSP
BAT
V
SET
I
TH
GND
5
4
24
23
1
3
2
21
22
18
19
12
6.04k
0.1µF
5k
0.033Ω
20µF
10µH
0.01µF
0.0015µF
0.12µF
SafetySignal
0.1µF
SMBALERT#
SMBCLK
SMBDAT
Figure 1. 4A Smart Battery Charger
sn4100 4100is
Information furnished by Linear Technology Corporation is believed to be accurate and reliable.
However, no responsibility is assumed for its use. Linear Technology Corporation makes no represen-
tation that the interconnection of its circuits as described herein will not infringe on existing patent rights.
U
0.025Ω
SMART BATTERY
20µF
100Ω
SMBCLK
SMBDAT
U
U
4100 TA01
1
LTC4100
ABSOLUTE
(Note 1)
AXI U RATI GS
PACKAGE/ORDER I FOR ATIO
TOP VIEW
TGATE
PGND
BGATE
INFET
DCIN
CHGEN
SMBALERT
SDA
SCL
1
2
3
4
5
6
7
8
9
24 CLP
23 CLN
22 BAT
21 CSP
20 I
DC
19 I
TH
18 V
SET
17 V
DD
16 THA
15 THB
14 V
LIM
13 I
LIM
Voltage from V
DD
to GND ................................ 7V/–0.3V
Voltage from CHGEN, DCDIV, SDA, SCL
and SMBALERT to GND .............................. 7V/–0.3V
Voltage from DCIN, CLP, CLN to GND ........... 32V/–0.3V
PGND wrt. GND ....................................................
±0.3V
CSP, BAT to GND .............................................. 28V/–5V
Operating Ambient Temperature Range (Note 4)
........................................................... – 40°C to 85°C
Junction Temperature Range ............... – 40°C to 125°C
Storage Temperature Range ................. – 65°C to 150°C
Lead Temperature (Soldering, 10 sec).................. 300°C
ORDER PART
NUMBER
LTC4100EG
ACP 10
DCDIV 11
GND 12
T
JMAX
= 125°C,
θ
JA
= 90°C/W
G PACKAGE
24-LEAD PLASTIC SSOP
Consult LTC Marketing for parts specified with wider operating temperature ranges.
ELECTRICAL CHARACTERISTICS
SYMBOL
I
DCIN
V
TOL
I
TOL
V
DD
Shutdown
Battery Leakage Current
UVLO
Undervoltage Lockout Threshold
V
DD
Power-Fail
DCIN Current in Shutdown
Current Sense Amplifier, CA1
Input Bias Current into BAT Pin
CMSL
CMSH
CA1/I
1
Input Common Mode Low
CA1/I
1
Input Common Mode High
PARAMETER
DCIN Operating Range
DCIN Operating Current
Charge Voltage Accuracy
Charge Current Accuracy (Note 3)
V
DD
Operating Voltage
The
q
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
DCIN
= 20V, V
DD
= 3.3V, V
BAT
= 12V unless otherwise noted. (Note 4)
CONDITIONS
q
MIN
6
TYP
3
MAX
28
5
0.8
1
3
5
5.5
UNITS
V
mA
%
%
%
%
V
µA
V
V
mA
µA
V
Charging
(Note 2)
q
–0.8
–1
–3
–5
3
15
4.2
4.7
2
11.66
V
CSP
– V
BAT
Target = 102.3mV
I
DAC
= 0xFFFF
0V
≤
V
DCIN
≤
32V
DCIN = 0V, V
CLP
= V
CLN
= V
CSP
= V
BAT
DCIN Rising, V
BAT
= 0V
Part Held in Reset Until this V
DD
Present
V
CHGEN
= 0V
q
q
q
q
q
30
5.5
3
3
q
0
V
CLN
-0.2
V
DCIN
≤
28V
q
sn4100 4100is
2
U
V
W
U
U
W W
W
LTC4100
The
q
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
DCIN
= 20V, V
DD
= 3.3V, V
BAT
= 12V unless otherwise noted. (Note 4)
SYMBOL
I
TMAX
I
TREV
PARAMETER
Maximum Current Sense Threshold (V
CSP
-V
BAT
)
Reverse Current Threshold (V
CSP
-V
BAT
)
Transconductance
Source Current
Sink Current
Current Limit Amplifier
Transconductance
V
CLP
I
CLP
Current Limit Threshold
CLP Input Bias Current
Transconductance
Sink Current
OVSD
Overvoltage Shutdown Threshold as a Percent
of Programmed Charger Voltage
DCIN DetectionThreshold (V
DCIN
-V
CLP
)
Forward Regulation Voltage (V
DCIN
-V
CLP
)
Reverse Voltage Turn-Off Voltage (V
DCIN
-V
CLP
)
INFET “ON” Clamping Voltage (V
DCIN
-V
INFET
)
INFET “OFF” Clamping Voltage (V
DCIN
-V
INFET
)
Oscillator
f
OSC
f
MIN
DC
MAX
Regulator Switching Frequency
Regulator Switching Frequency in Drop Out
Regulator Maximum Duty Cycle
V
TGATE
High (V
CLN
-V
TGATE
)
V
BGATE
High
V
TGATE
Low (V
CLN
-V
TGATE
)
V
BGATE
Low
TGTR
TGTF
BGTR
BGTF
TGATE Transition Time
TGATE Rise Time
TGATE Fall Time
BGATE Transition Time
BGATE Rise Time
BGATE Fall Time
V
TGATE
at Shutdown (V
CLN
-V
TGATE
)
V
BGATE
at Shutdown
Duty Cycle
≥
98%
V
CSP
= V
BAT
I
TGATE
= –1mA
I
BGATE
= –1mA
I
TGATE
= 1mA
I
BGATE
= 1mA
C
LOAD
= 3000pF, 10% to 90%
C
LOAD
= 3000pF, 10% to 90%
C
LOAD
= 3000pF, 10% to 90%
C
LOAD
= 3000pF, 10% to 90%
I
TGATE
= –1µA
I
TGATE
= 1µA
50
50
40
40
5.6
5.6
255
20
98
300
25
99
50
10
10
50
110
100
90
80
100
100
345
kHz
kHz
%
mV
V
V
mV
ns
ns
ns
ns
mV
mV
I
INFET
= 1µA
I
INFET
= –25µA
DCIN Voltage Ramping Up
from V
CLP
-0.05V
Measured at I
TH,
V
ITH
= 1.4V
q
q
ELECTRICAL CHARACTERISTICS
Current Comparators I
CMP
and I
REV
CONDITIONS
V
ITH
= 2.4V
q
MIN
140
TYP
165
– 30
1
MAX
200
UNITS
mV
mV
mmho
µA
µA
mmho
Current Sense Amplifier, CA2
Measured at I
TH
, V
ITH
= 1.4V
Measured at I
TH
, V
ITH
= 1.4V
–40
40
1.5
93
100
100
1
36
102
107
110
107
mV
nA
mmho
µA
%
Voltage Error Amplifier, EA
Input P-Channel FET Driver (INFET)
q
q
q
q
0.0
0.17
25
0.25
50
6.5
0.25
V
mV
mV
V
V
–60
5
–25
5.8
Gate Drivers (TGATE, BGATE)
sn4100 4100is
3
LTC4100
The
q
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
DCIN
= 20V, V
DD
= 3.3V, V
BAT
= 12V unless otherwise noted. (Note 4)
SYMBOL
V
ACP
PARAMETER
DCDIV Threshold
DCDIV Hysteresis
DCDIV Input Bias Current
ACP V
OH
ACP V
OL
DCDIV to ACP Delay
SafetySignal Decoder
SafetySignal Trip (RES_COLD/RES_OR)
SafetySignal Trip (RES_IDEAL/RES_COLD)
SafetySignal Trip (RES_HOT/RES_IDEAL)
SafetySignal Trip (RES_UR/RES_HOT)
Time Between SafetySignal Measurements
DACs
Charging Current Resolution
Charging Current Granularity
Guaranteed Monotonic Above I
MAX
/16
R
LIMIT
= 0
R
LIMIT
= 10k
±1%
R
LIMIT
= 33k
±1%
R
LIMIT
= Open (or Short to V
DD
)
All Values of R
ILIM
All Values of R
VLIM
R
LIMIT
= 0 (0-1A)
Charging Current = 0x03FF (0x0400 Note 7)
R
LIMIT
= 10k
±1%,
(0-2A)
Charging Current = 0x07FE (0x0800 Note 7)
R
LIMIT
= 33k
±1%
(0-3A)
Charging Current = 0x0BFC (0x0C00 Note 7)
R
LIMIT
= 0pen (or Short to V
DD
) (0-4A)
Charging Current = 0x0FFC (0x1000 Note 7)
Charging Voltage Resolution
Charging Voltage Granularity
Guaranteed Monotonic (2.9V
≤
V
BAT
≤
28V)
97.3
97.3
72.3
97.3
11
16
10
1
2
4
4
80 (NOTE 5)
107.3
107.3
82.3
107.3
Bits
mA
mA
mA
mA
mA
mV
mV
mV
mV
Bits
mV
R
THA
= 1130Ω
±1%,
C
TH
= 1nF (Note 6)
R
THB
= 54.9Ω
±1%
R
THA
= 1130Ω
±1%,
C
TH
= 1nF (Note 6)
R
THB
= 54.9Ω
±1%
R
THA
= 1130Ω
±1%,
C
TH
= 1nF (Note 6)
R
THB
= 54.9Ω
±1%
R
THA
= 1130Ω
±1%,
C
TH
= 1nF (Note 6)
R
THB
= 54.9Ω
±1%
DCDIV = 1.3V
DCDIV = 1V
q
q
q
q
ELECTRICAL CHARACTERISTICS
AC Present Comparator
CONDITIONS
V
DCDIV
Rising from 1V to 1.4V
V
DCDIV
= 1.2V
I
ACP
= –2mA
I
ACP
= 1mA
V
DCDIV
= 1.3V
q
MIN
1.14
–1
2
TYP
1.20
25
MAX
1.26
1
0.5
10
UNITS
V
mV
µA
V
V
µs
kΩ
kΩ
kΩ
Ω
ms
ms
95
28.5
2.85
425
100
30
3
500
32
105
31.5
3.15
575
250
Wake-Up Charging Current (I
WAKE-UP
)
Charging Current Limit
CSP – BAT
sn4100 4100is
4
LTC4100
The
q
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
DCIN
= 20V, V
DD
= 3.3V, V
BAT
= 12V unless otherwise noted. (Note 4)
SYMBOL
PARAMETER
Charging Voltage Limit
CONDITIONS
R
VLIM
= 0
Charging Voltage = 0x2260 (Note 7)
R
VLIM
= 10k
±1%
Charging Voltage = 0x3330 (Note 7)
R
VLIM
= 33k
±1%
Charging Voltage = 0x4400 (Note 7)
R
VLIM
= 100k
±1%
Charging Voltage = 0x5400 DCIN
≥
22V (Note 7)
R
VLIM
= 0pen (or Short to V
DD
)
Charging Voltage = 0x6D60 DCIN
≥
29V (Note 7)
Logic Levels
V
IL
V
IH
V
OL
I
IL
I
IH
V
OL
V
OL
V
IL
V
IH
SCL/SDA Input Low Voltage
SCL/SDA Input High Voltage
SDA Output Low Voltage
SCL/SDA Input Current
SCL/SDA Input Current
SMBALERT Output Low Voltage
SMBALERT Output Pull-Up Current
CHGEN Output Low Voltage
CHGEN Output Pull-Up Current
CHGEN Input Low Voltage
CHGEN Input High Voltage
Power-On Reset Duration
t
HIGH
t
LOW
t
R
t
F
t
SU:STA
t
HD:STA
t
HD:DAT
t
TIMEOUT
SCL Serial Clock High Period
SCL Serial Clock Low Period
SDA/SCL Rise Time
SDA/SCL Fall Time
Start Condition Setup Time
StartCondition Hold Time
SDA to SCL Falling-Edge Hold Time,
Slave Clocking in Data
Time Between Receiving Valid
ChargingCurrent() and
ChargingVoltage() Commands
V
DD
= 3V
V
DD
= 5.5V
V
DD
Ramp from 0V to >3V in <5µs
I
PULL-UP
= 350µA, C
LOAD
= 250pF, R
PU
= 9.31k
I
PULL-UP
= 350µA, C
LOAD
= 250pF, R
PU
= 9.31k
C
LOAD
= 250pF, R
PU
= 9.31k
C
LOAD
= 250pF, R
PU
= 9.31k
q
q
q
q
q
q
q
q
q
q
ELECTRICAL CHARACTERISTICS
MIN
8.730
12.999
17.269
21.538
27.781
TYP
8.800
13.104
17.408
21.712
28.006
MAX
8.870
13.209
17.547
21.886
28.231
UNITS
V
V
V
V
V
0.8
2.1
0.4
–1
–1
1
1
0.5
–17.5
–10
–10
–3.5
0.4
–17.5
–3.5
0.9
2.5
3.9
100
4
4.7
15000
1000
300
4.7
4
300
140
175
210
V
V
V
µA
µA
V
µA
V
µA
V
V
V
V
µs
µs
µs
ns
ns
µs
µs
ns
sec
I
PULL-UP
= 350µA
V
SDA
, V
SCL
= V
IL
V
SDA
, V
SCL
= V
IH
I
PULL-UP
= 500µA
V
SMBALERT
= V
OL
I
OL
= 100µA
V
CHGEN
= V
OL
q
q
q
q
q
SMBus Timing (Refer to System Management Bus Specification, Revision 1.1, Section 2.1 for Timing Diagrams)
Note 1:
Absolute Maximum Ratings are those values beyond which the life
of a device may be impaired.
Note 2:
See Test Circuit.
Note 3:
Does not include tolerance of current sense resistor.
Note 4:
The LTC4100E is guaranteed to meet performance specifications
from 0°C to 70°C. Specifications over the –40°C to 85°C operating
temperature range are assured by design, characterization and correlation
with statistical process controls.
Note 5:
Current accuracy dependent upon circuit compensation and sense
resistor.
Note 6:
C
TH
is defined as the sum of capacitance on THA, THB and
SafetySignal.
Note 7:
The corresponding overrange bit will be set when a HEX value
greater than or equal to this value is used.
sn4100 4100is
5
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