LTC1729 Series
Li-Ion Battery Charger
Termination Controllers
FEATURES
s
s
s
s
s
s
s
s
s
DESCRIPTIO
s
Built-In Termination: 3-Hour Time-Out
C/10 Detection with Status Indicator
Trickle Charge Preconditioning If Cell < 2.7V
Charging Enabled When 0°C < T < 50°C
Automatic Charger Present Detection
Automatic Battery Present Detection
1- or 2-Cell, 4.1V/Cell or 4.2V/Cell Options
Precision Internal 0.2% Voltage Feedback Divider
Compatible with LT1505/LT1510/LT1511/
LT1512/LT1513/LT1769
Small Footprint/Low Profile
The LTC
®
1729 series is a family of smart termination
controllers for lithium-ion battery chargers. These ICs
provide trickle charge preconditioning, temperature charge
qualification, time or charge current termination, auto-
matic charger and battery detection and status output.
Combining the LTC1729 series part with the LT
®
1510
(1.5A), LT1769 (2A), LT1511 (3A) and LT1505 (> 4A)
step-down chargers is a simple operation. Connecting six
pins from the LTC1729 series part to the step-down
chargers completes the integration. The LTC1729 termi-
nation controllers are also compatible with step-down/
step-up (SEPIC) chargers, including the LT1512 (2A switch)
and LT1513 (3A switch).
The LTC1729 series is available in the 8-pin MSOP and SO
packages.
, LTC and LT are registered trademarks of Linear Technology Corporation.
APPLICATIO S
s
s
s
s
Cellular Phones
PDAs
Cradle Chargers
Camcorders
TYPICAL APPLICATIO
0.22µF
L1**
10µH
MMBD914L
MBRM120T3
SW
LT1510-5
PROG
BOOST
GND
OVP
SENSE
BAT
V
C
0.1µF
1k
V
CC
1µF
300Ω
6.19k
+
C
OUT
***
22µF
+
4.2V
LTC1729-4.2
1
2
200Ω
1µF
3
4
OVP
BAT
SENSE
GND
V
CC
V
C
STATUS
NTC
8
7
6
1729 F01
0.1µF
5
10k NTC THERMISTOR, NTHS1206N02 VISHAY/DALE
NOTE: EITHER A THERMISTOR OR 10k RESISTOR MUST BE PRESENT
OPTION: TIE RESISTOR TO STATUS FOR
CHARGE TERMINATION AT
LOW CHARGING CURRENT
* TOKIN OR MARCON SURFACE MOUNT
** COILTRONICS TP3-100, 10µH, 2.2mm HEIGHT
(0.8A CHARGING CURRENT)
COILTRONICS TP1 SERIES, 10µH, 1.8mm
HEIGHT (<0.5A CHARGING CURRENT)
*** PANASONIC EEFCD1B220
†
LUMEX SML-LX0805GW-TR
Figure 1. 500kHz Li-Ion Cell Phone Charger (0.8A)
U
MBRM120T3
C
IN
*
10µF
INPUT POWER
8.2V TO 20V
1.4k
D1
†
CHARGE STATUS
U
U
1
LTC1729 Series
ABSOLUTE
AXI U
RATI GS
V
CC
......................................................................... 30V
SENSE, V
BAT
, NTC .................................... – 0.3V to 15V
V
C
............................................................. – 0.3V to 15V
OVP ............................................................ – 0.3V to 5V
PACKAGE/ORDER I FOR ATIO
ORDER PART
NUMBER
TOP VIEW
OVP
BAT
SENSE
GND
1
2
3
4
8
7
6
5
V
CC
V
C
STATUS
NTC
LTC1729CMS8-4.1
LTC1729CMS8-4.2
LTC1729CMS8-8.2
LTC1729CMS8-8.4
MS8 PART MARKING
LTLY
LTJH
LTLZ
LTJG
MS8 PACKAGE
8-LEAD PLASTIC MSOP
T
JMAX
= 150°C,
θ
JA
= 200°C/ W
Consult factory for Industrial and Military grade parts.
ELECTRICAL CHARACTERISTICS
The
q
denotes specifications which apply over the full operating temperature range, otherwise specifications are T
A
= 25°C, V
IN
= 8V
SYMBOL
I
CC
PARAMETER
V
CC
Supply Current
CONDITIONS
V
IN
= 5V (Below UVLO)
V
IN
= 8V, V
BAT
> 4.5V, No Bat
V
IN
= 8V, V
BAT
= 2.5V Trickle
V
IN
= 8V, V
BAT
= 3.5V Charge
q
q
q
q
q
DC CHARACTERISTICS
1
1.0
10
0.5
5.5
5.0
–1
40
– 19
– 2.7
4.25
4.25
4.25
2.55
2.45
85
5
1.4
17
3.0
6.5
6.0
– 0.1
73
– 12
– 1.3
4.5
4.51
4.50
2.7
2.6
100
±1
12
2.0
21
5.0
7.5
7.0
1
120
– 9.5
– 0.5
4.75
4.75
4.75
2.85
2.75
115
±2.5
µA
mA
mA
mA
V
V
µA
µA
mA
mA
V
V
V
V
V
µA
mV
V
LKOH
V
LKOL
I
VBAT
V
IN
Undervoltage Lockout High
V
IN
Undervoltage Lockout Low
V
BAT
Current
V
IN
= 5V (Below UVLO), V
BAT
= 4.2V
V
IN
= 8V, V
BAT
= 4.25V No Bat
V
IN
= 8V, V
BAT
= 2.5V Trickle
V
IN
= 8V, V
BAT
= 3.5V Charge
No Bat (External 200µA Pull-Up on V
BAT
)
High Going Threshold
Low Going Threshold
High Going Threshold
Low Going Threshold
Charge State, V
SENSE
= 3V
Charge State, V
C10
= (V
BAT
– V
SENSE
)
V
CLAMP
V
MAX
V
MIN
I
SENSE
V
C10
V
BAT
Clamp
High V
BAT
Threshold
Low V
BAT
Threshold
SENSE Pin Current
SENSE Pin C/10 Offset
2
U
U
W
W W
U
W
(Note 1)
STATUS .................................................... – 0.3V to 30V
Operating Temperature Range .................... 0°C to 70°C
Storage Temperature Range ................ – 65°C to 150°C
Lead Temperature (Soldering, 10 sec)................. 300°C
ORDER PART
NUMBER
TOP VIEW
OVP
BAT
SENSE
GND
1
2
3
4
8 V
CC
7 V
C
6 STATUS
5 NTC
LTC1729CS8-4.1
LTC1729CS8-4.2
LTC1729CS8-8.2
LTC1729CS8-8.4
S8 PART MARKING
172941
172942
172982
172984
S8 PACKAGE
8-LEAD PLASTIC SO
T
JMAX
= 150°C,
θ
JA
= 150°C/ W
LTC1729-4.1/LTC1729-4.2
MIN
TYP
MAX
UNITS
q
q
q
q
q
q
q
q
q
q
LTC1729 Series
ELECTRICAL CHARACTERISTICS
The
q
denotes specifications which apply over the full operating temperature range, otherwise specifications are T
A
= 25°C, V
IN
= 8V
SYMBOL
I
NTC
V
NTC-RESET
V
NTC-HOT
V
NTC-COLD
V
OVP
V
OL-ST
V
OL-VC
I
SOFT
PARAMETER
NTC Pin Current
Thermistor Pin Reset Threshold
Thermistor Pin Hot Hold Threshold
Thermistor Pin Cold Hold Threshold
OVP Pin Voltage
Output Low Voltage-STATUS Pin
Output Low Voltage-V
C
Pin
Status Soft Pull-Down Current
High Going Threshold
Low Going Threshold
High Going Threshold
Low Going Threshold
V
BAT
= 4.1V or V
BAT
= 4.2V
I
O
= 3mA
I
O
= 1mA
V
STATUS
= 4.5V
CONDITIONS
V
NTC
= 1V
q
q
q
q
q
q
q
q
q
q
LTC1729-4.1/LTC1729-4.2
MIN
TYP
MAX
90
0.160
0.460
0.380
2.70
2.10
2.455
2.460
0.5
0.35
40
100
0.206
0.486
0.405
2.79
2.23
2.465
2.465
0.9
0.6
50
110
0.240
0.510
0.430
2.90
2.35
2.475
2.470
1.2
0.75
65
UNITS
µA
V
V
V
V
V
V
V
V
V
µA
The
q
denotes specifications which apply over the full operating temperature range, otherwise specifications are T
A
= 25°C, V
IN
= 12V
SYMBOL
I
CC
PARAMETER
V
CC
Supply Current
CONDITIONS
V
IN
= 9V (Below UVLO)
V
IN
= 12V, V
BAT
> 9V, No Bat
V
IN
= 12V, V
BAT
= 5V Trickle
V
IN
= 12V, V
BAT
= 7V Charge
q
q
q
q
q
LTC1729-8.2/LTC1729-8.4
MIN
TYP
MAX
1
1.0
10
0.5
9.5
8.5
–1
60
– 19
– 2.7
8.5
8.5
8.5
5.1
4.9
85
90
0.160
0.460
0.380
2.70
2.10
2.455
2.460
0.5
0.35
40
6
1.4
17
3.0
10.4
9.6
– 0.1
95
– 12
– 1.3
9
9.013
9
5.4
5.2
100
±1
100
0.206
0.486
0.405
2.79
2.23
2.465
2.465
0.9
0.6
50
12
2.0
21
5.0
11.4
10.5
1
140
– 9.5
– 0.5
9.5
9.5
9.5
5.7
5.5
115
±2.5
110
0.240
0.510
0.430
2.90
2.35
2.475
2.470
1.2
0.75
65
UNITS
µA
mA
mA
mA
V
V
µA
µA
mA
mA
V
V
V
V
V
µA
mV
µA
V
V
V
V
V
V
V
V
V
µA
DC CHARACTERISTICS
V
LKOH
V
LKOL
I
VBAT
V
IN
Undervoltage Lockout High
V
IN
Undervoltage Lockout Low
V
BAT
Current
V
IN
= 9V (Below UVLO), V
BAT
= 8.4V
V
IN
= 12V, V
BAT
= 8.5V No Bat
V
IN
= 12V, V
BAT
= 5V Trickle
V
IN
= 12V, V
BAT
= 7V Charge
No Bat (External 200µA Pull-Up on V
BAT
)
High Going Threshold
Low Going Threshold
High Going Threshold
Low Going Threshold
Charge State, V
SENSE
= 7V
Charge State, V
C10
= (V
BAT
– V
SENSE
)
V
NTC
= 1V
High Going Threshold
Low Going Threshold
High Going Threshold
Low Going Threshold
V
BAT
= 8.2V or V
BAT
= 8.4V
I
O
= 3mA
I
O
= 1mA
V
STATUS
= 4.5V
q
q
q
q
q
q
q
q
q
q
q
q
q
q
q
q
q
q
q
q
V
CLAMP
V
MAX
V
MIN
I
SENSE
V
C10
I
NTC
V
NTC-RESET
V
NTC-HOT
V
NTC-COLD
V
OVP
V
OL-ST
V
OL-VC
I
SOFT
V
BAT
Clamp
High V
BAT
Threshold
Low V
BAT
Threshold
SENSE Pin Current
SENSE Pin C/10 Offset
NTC Pin Current
Thermistor Pin Reset Threshold
Thermistor Pin Hot Hold Threshold
Thermistor Pin Cold Hold Threshold
OVP Pin Voltage
Output Low Voltage-STATUS Pin
Output Low Voltage-V
C
Pin
Status Soft Pull-Down Current
3
LTC1729 Series
ELECTRICAL CHARACTERISTICS
The
q
denotes specifications which apply over the full operating temperature range, otherwise specifications are TA = 25°C. (Note 2)
SYMBOL
TIMER1
TIMER2
TIMER3
TIMER4
t
OSC
PARAMETER
Timer for Trickle-Charge Preconditioning
Timer for Charging
Timer for V
MAX
Filter
Timer for V
C/10
Filter
Oscillator Period
CONDITIONS
q
q
q
q
q
MIN
0.869
2.61
0.764
3.055
6.66
TYP
1
3
0.859
3.5
7.63
MAX
1.305
3.55
1.043
4.17
9.09
UNITS
Hr
Hr
sec
sec
µs
AC CHARACTERISTICS
Note 1:
Absolute Maximum Ratings are those values beyond which the life
of a device may be impaired.
Note 2:
V
IN
= 8V for LTC1729-4.1/LTC1729-4.2; V
IN
= 12V for
LTC1729-8.2/LTC1729-8.4
TYPICAL PERFOR A CE CHARACTERISTICS
I
VBAT
vs Temperature (4.2V Version)
14
12
10
V
BAT
= 2.5V
14
12
10
I
VBAT
(mA)
I
VBAT
(mA)
I
VBAT
(mA)
8
6
4
2
0
0
25
50
TEMPERATURE (°C)
1729 G01
75
I
VBAT
vs V
CC
(8.4V Version)
12
V
BAT
= 5V
10
8
I
VBAT
(mA)
I
CC
(mA)
I
CC
(mA)
6
4
2
0
10
14
18
22
V
CC
(V)
26
30
1729 G04
V
BAT
= 7V
4
U W
I
VBAT
vs Temperature (8.4V Version)
V
BAT
= 5V
14
12
I
VBAT
vs V
CC
(4.2V Version)
V
BAT
= 2.5V
10
8
6
4
2
V
BAT
= 3.5V
0
100
0
25
50
TEMPERATURE (°C)
1729 G02
8
6
4
2
0
75
100
6
10
14
18
V
CC
(V)
22
26
30
1729 G03
I
CC
vs V
CC
(4.2V Version)
14
12
10
8
6
4
2
V
BAT
= 3.5V
V
BAT
= 2.5V
14
12
10
8
6
4
2
6
10
14
18
V
CC
(V)
22
26
30
1729 G05
I
CC
vs V
CC
(8.4V Version)
V
BAT
= 5V
V
BAT
= 7V
10
14
18
22
V
CC
(V)
26
30
1729 G06
LTC1729 Series
PI FU CTIO S
OVP (Pin 1):
Connection to an Internal Precision Resistor
Divider Used as a Voltage Feedback Monitor for Constant-
Voltage Mode Charging.
BAT (Pin 2):
Input to Battery Monitor Circuits and OVP
Resistor Divider. The battery monitor circuits activate
trickle charge preconditioning, battery present detection
and
C/10
current detection. This pin is in a high impedance
state when V
CC
is below the undervoltage lockout thresh-
old. During trickle charge preconditioning and charging
the BAT pin sources 12mA and 1.3mA respectively. The
current sources are clamped from driving the BAT pin
above 4.5V/cell with an internal pull-down transistor.
In the No Bat, Done and Pause states or the Hold and Reset
modes, the current sources are turned off, leaving only the
55k OVP divider as a load on the BAT pin. Most chargers
have a 200µA current source that will compensate for this
50µA to 80µA load.
SENSE (Pin 3):
Input to
C/10
Current Detection Circuit.
This pin sinks 100µA during the Charge state which is used
to program the
C/10
current threshold.
GND (Pin 4):
Ground.
NTC (Pin 5):
Input to the NTC Thermistor Monitoring
Circuits. When the voltage on this pin is above 2.79V
(cold) or below 0.405V (hot), the state machine is locked
in the present state and the timer is stopped. This is called
the Hold mode. While in the Hold mode, the charger is
turned off via the V
C
pin and the current sources on BAT
and SENSE pins are turned off. The STATUS pin is not
affected.
If the NTC pin is below 0.2V, the state machine is forced
in the reset mode with all the timers cleared to zero. The
current sources on the BAT pin and SENSE pin are
disabled leaving the 55k OVP divider. The STATUS pin is
pulled low in the Reset mode.
There is a 100µA current source on the NTC pin to bias the
NTC thermistor. This current source is active when the V
CC
is greater than the undervoltage lockout threshold.
STATUS (Pin 6):
Open-Drain Output for
C/10
Charge
Termination Detection Circuit. When in the Charge state,
this pin is pulled low. Once the charge current drops below
the
C/10
current threshold for three seconds, the pull-
down transistor is disabled, and a 50µA pull-down current
sink remains activated until the 1- or 3-hour time-out or
the battery or wall adapter is removed.
V
C
(Pin 7):
Open-Drain Output for Turning Off the Charger.
When this pin is open circuit, the charger is active.
Normally this pin allows the charger to be active for three
hours.
V
CC
(Pin 8):
Input Supply. For 4.1V or 4.2V single cell
operation, V
CC
should be between 8V and 28V with the IC
turning off when V
CC
drops below 6V. For 2-cell applica-
tions, the undervoltage lockout is 10.4V with a minimum
V
CC
of 12V. Removing the wall adapter will trigger an
undervoltage lockout and put the IC in a high impedance
condition. When the supply is connected, the IC is initial-
ized in the Reset mode with the state machine forced in the
Charge state with all the timers set to zero.
U
U
U
5
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