LT1510/LT1510-5
Constant-Voltage/
Constant-Current Battery Charger
FEATURES
s
s
s
s
s
s
s
s
s
Charges NiCd, NiMH and Lithium-Ion Batteries ––
Only One
1
/
10
W Resistor Is Needed to Program
Charging Current
High Efficiency Current Mode PWM with 1.5A
Internal Switch and Sense Resistor
3% Typical Charging Current Accuracy
Precision 0.5% Voltage Reference for Voltage
Mode Charging or Overvoltage Protection
Current Sensing Can Be at Either Terminal of
the Battery
Low Reverse Battery Drain Current: 3µA
Charging Current Soft Start
Shutdown Control
500kHz Version Uses Small Inductor
plest, most efficient solution to fast-charge modern re-
chargeable batteries including lithium-ion (Li-Ion), nickel-
metal-hydride (NiMH)* and nickel-cadmium (NiCd)* that
require constant-current and/or constant-voltage charg-
ing. The internal switch is capable of delivering 1.5A DC
current (2A peak current). The 0.1Ω onboard current
sense resistor makes the charging current programming
very simple. One resistor (or a programming current from
a DAC) is required to set the full charging current (1.5A) to
within 5% accuracy. The LT1510 with 0.5% reference
voltage accuracy meets the critical constant-voltage charg-
ing requirement for lithium cells.
The LT1510 can charge batteries ranging from 2V to 20V.
Ground sensing of current is not required and the battery’s
negative terminal can be tied directly to ground. A saturat-
ing switch running at 200kHz (500kHz for LT1510-5) gives
high charging efficiency and small inductor size. A block-
ing diode is not required between the chip and the battery
because the chip goes into sleep mode and drains only 3µA
when the wall adaptor is unplugged. Soft start and shutdown
features are also provided. The LT1510 is available in a 16-pin
fused lead power SO package with a thermal resistance of
50°C/W, an 8-pin SO and a 16-pin PDIP.
, LTC and LT are registered trademarks of Linear Technology Corporation.
* NiCd and NiMH batteries require charge termination circuitry (not shown in Figure 1).
APPLICATIONS
s
s
Chargers for NiCd, NiMH and Lithium Batteries
Step-Down Switching Regulator with Precision
Adjustable Current Limit
DESCRIPTION
With switching frequency as high as 500kHz, The LT
®
1510
current mode PWM battery charger is the smallest, sim-
TYPICAL APPLICATIONS
C1
0.22µF
D1
MBRM120T3
SW
V
CC
D3
MBRM120T3
C1
D1
0.22µF 1N5819
D3
1N5819
SW
V
CC
11V TO 28V
+
C
IN
*
10µF
1µF
BOOST
L1**
10µH
D2
MMBD914L
PROG
LT1510-5
GND
OVP
V
C
0.1µF
SENSE
BAT
+
C
OUT***
22µF
NOTE: COMPLETE LITHIUM-ION CHARGER, NO TERMINATION REQUIRED
* TOKIN OR MARCON CERAMIC 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
† OPTIONAL, SEE APPLICATIONS INFORMATION
Figure 1. 500kHz Smallest Li-Ion Cell Phone Charger (0.8A)
U
U
U
8.2V TO 20V
+
+
–
BOOST
PROG
C
IN
*
10µF
1µF
+
–
3.83k
300Ω
6.19k
L1**
33µH
D2
1N914
LT1510
GND
OVP
SENSE
BAT
V
C
0.1µF
300Ω
1k
1k
+
4.2V
Q3
†
2N7002
R3
70.6k
0.25%
R4
100k
0.25%
1510 F01
+
C
OUT
22µF
TANT
+
4.2V
+
4.2V
Q3
†
VN2222
R3
240k
0.25%
R4
100k
0.25%
1510 F02
NOTE: COMPLETE LITHIUM-ION CHARGER, NO TERMINATION REQUIRED
* TOKIN OR MARCON CERAMIC SURFACE MOUNT
** COILTRONICS CTX33-2
†
OPTIONAL, SEE APPLICATIONS INFORMATION
Figure 2. Charging Lithium Batteries (Efficiency at 1.3A > 87%)
1
LT1510/LT1510-5
ABSOLUTE
MAXIMUM
RATINGS
Supply Voltage (V
MAX
) ............................................ 30V
Switch Voltage with Respect to GND ...................... – 3V
Boost Pin Voltage with Respect to V
CC
................... 30V
Boost Pin Voltage with Respect to GND ................. – 5V
V
C
, PROG, OVP Pin Voltage ...................................... 8V
I
BAT
(Average) ........................................................ 1.5A
Switch Current (Peak)............................................... 2A
Storage Temperature Range ................. – 65°C to 150°C
Operating Ambient Temperature Range
Commercial ............................................. 0°C to 70°C
Extended Commercial (Note 7) ........... – 40°C to 85°C
Industrial (Note 8) .............................. – 40°C to 85°C
Operating Junction Temperature Range
LT1510C (Note 7) ............................. – 40°C to 125°C
LT1510I ............................................ – 40°C to 125°C
Lead Temperature (Soldering, 10 sec).................. 300°C
PACKAGE/ORDER INFORMATION
TOP VIEW
SW 1
BOOST 2
GND 3
SENSE 4
8
7
6
5
V
CC
PROG
V
C
BAT
**GND
SW
BOOST
GND
OVP
NC
SENSE
**GND
1
2
3
4
5
6
7
8
TOP VIEW
16 GND**
15 V
CC2
14 V
CC1
13 PROG
12 V
C
11 NC
10 BAT
9
GND**
S8 PACKAGE
8-LEAD PLASTIC SO
T
JMAX
= 125°C,
θ
JA
= 125°C/ W
ORDER PART
NUMBER
LT1510CS8
LT1510IS8
S8 PART MARKING
1510
1510I
Consult factory for Military grade parts.
GN PACKAGE (0.015 IN)
16-LEAD PLASTIC SSOP
T
JMAX
= 125°C,
θ
JA
= 75°C/ W
** FOUR CORNER PINS ARE FUSED TO
INTERNAL DIE ATTACH PADDLE FOR
HEAT SINKING. CONNECT THESE FOUR
PINS TO EXPANDED PC LANDS FOR
PROPER HEAT SINKING.
ELECTRICAL CHARACTERISTICS
V
CC
= 16V, V
BAT
= 8V, V
MAX
(maximum operating V
CC
) = 28V, no load on any outputs, unless otherwise noted. (Notes 7, 8)
PARAMETER
Overall
Supply Current
DC Battery Current, I
BAT
(Note 1)
V
PROG
= 2.7V, V
CC
≤
20V
V
PROG
= 2.7V, 20V < V
CC
≤
V
MAX
8V
≤
V
CC
≤
25V, 0V
≤
V
BAT
≤
20V, T
J
< 0°C
R
PROG
= 4.93k
R
PROG
= 3.28k (Note 4)
R
PROG
= 49.3k
T
J
< 0°C
V
CC
= 28V, V
BAT
= 20V
R
PROG
= 4.93k
R
PROG
= 49.3k
q
q
q
q
q
q
q
q
q
CONDITIONS
2
U
U
W
W W
U
W
ORDER PART
NUMBER
**GND
1
2
3
4
5
6
7
8
TOP VIEW
16 GND**
15 V
CC2
14 V
CC1
13 PROG
12 V
C
11 BAT
10 GND
9
GND**
ORDER PART
NUMBER
LT1510CN
LT1510CS
LT1510IN
LT1510IS
LT1510CGN
LT1510IGN
LT1510-5CGN
LT1510-5IGN
SW
BOOST
GND
OVP
SENSE
GND
**GND
GN PART
MARKING
1510
1510I
15105
15105I
N PACKAGE
16-LEAD PDIP
S PACKAGE*
16-LEAD PLASTIC SO
T
JMAX
= 125°C,
θ
JA
= 75°C/ W (N)
T
JMAX
= 125°C,
θ
JA
= 50°C/ W (S)*
* V
CC1
AND V
CC2
SHOULD BE CONNECTED
TOGETHER CLOSE TO THE PINS.
** FOUR CORNER PINS ARE FUSED TO
INTERNAL DIE ATTACH PADDLE FOR
HEAT SINKING. CONNECT THESE FOUR
PINS TO EXPANDED PC LANDS FOR
PROPER HEAT SINKING.
MIN
TYP
2.90
2.91
MAX
4.3
4.5
1.09
1.07
1.65
125
130
1.07
125
UNITS
mA
mA
A
A
A
mA
mA
A
mA
0.91
0.93
1.35
75
70
0.93
75
1.0
1.5
100
1.0
100
LT1510/LT1510-5
ELECTRICAL CHARACTERISTICS
V
CC
= 16V, V
BAT
= 8V, V
MAX
(maximum operating V
CC
) = 28V, no load on any outputs, unless otherwise noted.
PARAMETER
Overall
Minimum Input Operating Voltage
Reverse Current from Battery (When V
CC
Is Not
Connected, V
SW
Is Floating)
Boost Pin Current
Undervoltage Lockout
V
BAT
≤
20V, 0°C
≤
T
J
≤
70°C
V
CC
– V
BOOST
≤
20V
20V < V
CC
– V
BOOST
≤
28V
2V
≤
V
BOOST
– V
CC
≤
8V (Switch ON)
8V < V
BOOST
– V
CC
≤
25V (Switch ON)
V
CC
= 10V
I
SW
= 1.5A, V
BOOST
– V
SW
≥
2V (Note 4)
I
SW
= 1A, V
BOOST
– V
SW
< 2V (Unboosted)
V
BOOST
= 24V, I
SW
≤
1A
V
SW
= 0V, V
CC
≤
20V
20V < V
CC
≤
28V
q
q
q
q
q
q
q
q
q
CONDITIONS
MIN
6.2
TYP
7
3
0.10
0.25
6
8
MAX
7.8
15
20
30
11
14
UNITS
V
µA
µA
µA
mA
mA
Switch
Switch ON Resistance
q
q
0.3
20
2
4
2
4
2.4
0.08
0.2
0.5
2.0
35
100
200
V
CC
– 2
20
Ω
Ω
mA/A
µA
µA
V
µA
mA
∆I
BOOST
/∆I
SW
During Switch ON
Switch OFF Leakage Current
Maximum V
BAT
with Switch ON
Minimum I
PROG
for Switch ON
Minimum I
PROG
for Switch OFF at V
PROG
≤
1V
Current Sense Amplifier Inputs (SENSE, BAT)
Sense Resistance (R
S1
)
Total Resistance from SENSE to BAT (Note 3)
BAT Bias Current (Note 5)
Input Common Mode Limit (Low)
Input Common Mode Limit (High)
Reference
Reference Voltage (Note 1) S8 Package
Reference Voltage (Note 2) 16-Pin
Reference Voltage Tolerance, 16-Pin Only
q
1
0.12
0.25
– 375
1300
V
CC
– 2
Ω
Ω
µA
µA
V
V
V
V
V
V
V
kHz
kHz
kHz
kHz
kHz
kHz
%
%
%
V
C
< 0.3V
V
C
> 0.6V
q
q
– 200
700
– 0.25
R
PROG
= 4.93k, Measured at PROG Pin
R
PROG
= 3.28k, Measured at OVP with
VA Supplying I
PROG
and Switch OFF
8V
≤
V
CC
≤
28V, 0°C
≤
T
J
≤
70°C
8V
≤
V
CC
≤
28V, 0°C
≤
T
J
≤
125°C
8V
≤
V
CC
≤
28V, T
J
< 0°C
LT1510
LT1510-5
All Conditions of V
CC
, Temperature, LT1510
LT1510, T
J
< 0°C
LT1510-5
LT1510-5, T
J
< 0°C
LT1510
LT1510, T
A
= 25°C (Note 8)
LT1510-5 (Note 9)
q
2.415
2.453
2.465
2.465
2.465
2.515
2.477
2.480
2.489
2.489
220
550
230
230
575
575
q
q
q
2.446
2.441
2.430
180
440
Oscillator
Switching Frequency
Switching Frequency Tolerance
200
500
200
500
q
q
q
q
q
q
170
160
425
400
87
90
77
Maximum Duty Cycle
93
81
3
LT1510/LT1510-5
ELECTRICAL CHARACTERISTICS
V
CC
= 16V, V
BAT
= 8V, V
MAX
(maximum operating V
CC
) = 28V, no load on any outputs, unless otherwise noted.
PARAMETER
Current Amplifier (CA2)
Transconductance
Maximum V
C
for Switch OFF
I
VC
Current (Out of Pin)
Voltage Amplifier (VA), 16-Pin Only
Transconductance (Note 2)
Output Source Current, V
CC
= 10V
OVP Input Bias Current
Output Current from 100µA to 500µA
V
PROG
= V
OVP
= V
REF
+ 10mV
At 0.75mA VA Output Current
q
CONDITIONS
V
C
= 1V, I
VC
=
±1µA
q
MIN
150
TYP
250
MAX
550
0.6
100
3
UNITS
µmho
V
µA
mA
mho
mA
nA
V
C
≥
0.6V
V
C
< 0.45V
0.5
1.3
50
1.2
2.5
150
The
q
denotes specifications which apply over the specified
temperature range.
Note 1:
Tested with Test Circuit 1.
Note 2:
Tested with Test Circuit 2.
Note 3:
Sense resistor R
S1
and package bond wires.
Note 4:
Applies to 16-pin only. 8-pin packages are guaranteed but not
tested at – 40°C.
Note 5:
Current (≈ 700µA) flows into the pins during normal operation and
also when an external shutdown signal on the V
C
pin is greater than 0.3V.
Current decreases to
≈
200µA and flows out of the pins when external
shutdown holds the V
C
pin below 0.3V. Current drops to near zero when
input voltage collapses. See external Shutdown in Applications Information
section.
Note 6:
A linear interpolation can be used for reference voltage
specification between 0°C and – 40°C.
Note 7:
Commercial grade device specifications are guaranteed over the
0°C to 70°C temperature range. In addition, commercial grade device
specifications are assured over the –40°C to 85°C temperature range by
design or correlation, but are not production tested.
Maximum allowable ambient temperature may be limited by power
dissipation. Parts may not necessarily be operated simultaneously at
maximum power dissipation and maximum ambient temperature.
Temperature rise calculations must be done as shown in the Applications
Information section to ensure that maximum junction temperature does
not exceed the 125°C limit. With high power dissipation, maximum
ambient temperature may be less than 70°C.
Note 8:
Industrial grade device specifications are guaranteed over the
– 40°C to 85°C temperature range.
Note 9:
91% maximum duty cycle is guaranteed by design if V
BAT
or V
X
(see Figure 8 in Application Information) is kept between 3V and 5V.
Note 10:
V
BAT
= 4.2V.
TYPICAL PERFORMANCE CHARACTERISTICS
Thermally Limited Maximum
Charging Current, 8-Pin SO
1.3
MAXIMUM CHARGING CURRENT (A)
MAXIMUM CHARGING CURRENT (A)
1.1
1.3
MAXIMUM CHARGING CURRENT (A)
(θ
JA
=125°C/W)
T
AMAX
= 60°C
T
JMAX
=125°C
4V BATTERY
0.9
8V BATTERY
0.7
12V BATTERY
0.5
16V BATTERY
0.3
0
5
15
10
INPUT VOLTAGE (V)
20
25
1510 G12
4
U W
Thermally Limited Maximum
Charging Current, 16-Pin SO
1.5
4V BATTERY
8V BATTERY
12V BATTERY
1.1
16V BATTERY
0.9
1.5
Thermally Limited Maximum
Charging Current, 16-Pin GN
1.3
4V BATTERY
1.1
8V BATTERY
0.9
0.7
(θ
JA
=50°C/W)
T
AMAX
=60°C
T
JMAX
=125°C
0
5
15
10
INPUT VOLTAGE (V)
20
25
1510 G13
0.7
θ
JA
= 80°C/W
T
AMAX
= 60°C
T
JMAX
= 125°C
0
5
12V BATTERY
16V BATTERY
20
25
0.5
0.5
15
10
INPUT VOLTAGE (V)
LT1510 • TPC14
LT1510/LT1510-5
TYPICAL PERFORMANCE CHARACTERISTICS
Efficiency of Figure 2 Circuit
100
98
96
94
V
CC
= 15V (EXCLUDING DISSIPATION
ON INPUT DIODE D3)
V
BAT
= 8.4V
FREQUENCY (kHz)
EFFICIENCY (%)
I
CC
(mA)
92
90
88
86
84
82
80
0.1
0.3
0.5
0.7 0.9
I
BAT
(A)
1.1
1.3
1.5
I
CC
vs V
CC
7.0
MAXIMUM DUTY CYCLE
6.5
0°C
25°C
125°C
5.5
∆V
REF
(V)
I
CC
(mA)
6.0
∆V
OVP
(mV)
5.0
4.5
0
5
10
15
V
CC
(V)
20
25
30
1510 G03
Maximum Duty Cycle
98
97
96
–1.20
–1.08
–0.96
–0.84
–0.60
–0.48
–0.36
–0.24
–0.12
0
DUTY CYCLE (%)
I
PROG
(mA)
95
I
VC
(mA)
94
93
92
91
90
0
20
40
60
80
100
120
140
TEMPERATURE (°C)
1510 G09
U W
1510 G01
I
CC
vs Duty Cycle
8
V
CC
= 16V
7
6
5
0°C
4
3
2
1
0
0
10
20
30 40 50 60
DUTY CYCLE (%)
70
80
185
200
195
190
205
210
Switching Frequency vs
Temperature
125°C
25°C
180
–20
0
20
40 60 80 100 120 140
TEMPERATURE (°C)
1510 G05
1510 G04
V
REF
Line Regulation
0.003
0.002
I
VA
vs
∆V
OVP
(Voltage Amplifier)
4
3
0.001
0
ALL TEMPERATURES
2
125°C
1
–0.001
–0.002
–0.003
25°C
0
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
I
VA
(mA)
1510 G08
0
5
10
15
V
CC
(V)
20
25
30
1510 G02
V
C
Pin Characteristic
6
PROG Pin Characteristic
125°C
25°C
–0.72
0
0.12
–6
0
0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0
V
C
(V)
1510 G10
0
1
2
3
V
PROG
(V)
4
5
1510 G11
5
