LT1510CGN [Linear]
Constant-Voltage/ Constant-Current Battery Charger; 恒压/恒流充电器型号: | LT1510CGN |
厂家: | Linear |
描述: | Constant-Voltage/ Constant-Current Battery Charger |
文件: | 总16页 (文件大小:342K) |
中文: | 中文翻译 | 下载: | 下载PDF数据表文档文件 |
LT1510/LT1510-5
Constant-Voltage/
Constant-Current Battery Charger
FEATURES
■
plest, most efficient solution to fast-charge modern re-
chargeablebatteriesincludinglithium-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
voltageaccuracymeetsthecriticalconstant-voltagecharg-
ing requirement for lithium cells.
Charges NiCd, NiMH and Lithium-Ion Batteries ––
Only One 1/10W 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
■
The LT1510 can charge batteries ranging from 2V to 20V.
Groundsensingofcurrentisnotrequiredandthebattery’s
negative terminal can be tied directly to ground. A saturat-
ingswitchrunningat200kHz(500kHzforLT1510-5)gives
high charging efficiency and small inductor size. A block-
ing diode is not required between the chip and the battery
becausethechipgoesintosleepmodeanddrainsonly3µA
when the wall adaptor is unplugged. Soft start and shutdown
featuresarealsoprovided.TheLT1510isavailableina16-pin
fused lead power SO package with a thermal resistance of
50°C/W, an 8-pin SO and a 16-pin PDIP.
■
U
APPLICATIONS
■
Chargers for NiCd, NiMH and Lithium Batteries
Step-Down Switching Regulator with Precision
Adjustable Current Limit
■
U
DESCRIPTION
Withswitchingfrequencyashighas500kHz,TheLT®1510
current mode PWM battery charger is the smallest, sim-
, LTC and LT are registered trademarks of Linear Technology Corporation.
* NiCd and NiMH batteries require charge termination circuitry (not shown in Figure 1).
U
TYPICAL APPLICATIONS
D3
C1
D1
1N5819
D3
11V TO 28V
0.22µF
C1
0.22µF
1N5819
D1
MBRM120T3
SW
V
CC
8.2V TO 20V
MBRM120T3
+
+
SW
V
CC
C
*
IN
+
–
+
10µF
C
*
IN
+
–
10µF
BOOST
PROG
1µF
BOOST
PROG
L1**
33µH
300Ω
3.83k
1µF
LT1510
L1**
10µH
300Ω
D2
1N914
6.19k
LT1510-5
D2
MMBD914L
GND
V
0.1µF
C
1k
GND
V
0.1µF
C
1k
OVP
OVP
SENSE
BAT
+
SENSE
BAT
C
OUT
4.2V
+
22µF
†
+
C
OUT
22µF
***
Q3
4.2V
TANT
+
†
VN2222
Q3
4.2V
2N7002
R3
240k
R3
70.6k
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)
0.25%
0.25%
R4
NOTE: COMPLETE LITHIUM-ION CHARGER, NO TERMINATION REQUIRED
TOKIN OR MARCON CERAMIC SURFACE MOUNT
100k
0.25%
R4
*
100k
0.25%
***
PANASONIC EEFCD1B220
1510 F02
** COILTRONICS CTX33-2
OPTIONAL, SEE APPLICATIONS INFORMATION
†
1510 F01
†
OPTIONAL, SEE APPLICATIONS INFORMATION
Figure 1. 500kHz Smallest Li-Ion Cell Phone Charger (0.8A)
Figure 2. Charging Lithium Batteries (Efficiency at 1.3A > 87%)
1
LT1510/LT1510-5
W W U W
ABSOLUTE MAXIMUM RATINGS
Operating Ambient Temperature Range
Supply Voltage (VMAX)............................................ 30V
Switch Voltage with Respect to GND ...................... –3V
Boost Pin Voltage with Respect to VCC ................... 30V
Boost Pin Voltage with Respect to GND ................. –5V
VC, PROG, OVP Pin Voltage ...................................... 8V
IBAT (Average)........................................................ 1.5A
Switch Current (Peak)............................................... 2A
Storage Temperature Range ................. –65°C to 150°C
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
U
W U
PACKAGE/ORDER INFORMATION
ORDER PART
ORDER PART
NUMBER
TOP VIEW
TOP VIEW
TOP VIEW
NUMBER
SW
BOOST
GND
1
2
3
4
8
7
6
5
V
CC
1
2
3
4
5
6
7
8
GND**
1
2
3
4
5
6
7
8
GND**
16
15
14
13
12
11
10
9
16
15
14
13
12
11
10
9
**GND
SW
**GND
SW
PROG
V
CC2
V
CC2
LT1510CGN
LT1510IGN
LT1510-5CGN
LT1510-5IGN
LT1510CN
LT1510CS
LT1510IN
LT1510IS
V
C
V
V
BOOST
GND
BOOST
GND
CC1
CC1
SENSE
BAT
PROG
PROG
V
C
V
C
OVP
OVP
S8 PACKAGE
8-LEAD PLASTIC SO
NC
BAT
NC
SENSE
GND
BAT
GND
SENSE
**GND
TJMAX = 125°C, θJA = 125°C/ W
GND**
GND**
**GND
ORDER PART
NUMBER
GN PACKAGE (0.015 IN)
16-LEAD PLASTIC SSOP
S PACKAGE*
16-LEAD PLASTIC SO
N PACKAGE
16-LEAD PDIP
GN PART
MARKING
TJMAX = 125°C, θJA = 75°C/ W (N)
JMAX = 125°C, θJA = 50°C/ W (S)*
TJMAX = 125°C, θJA = 75°C/ W
T
LT1510CS8
LT1510IS8
** 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.
1510
*
VCC1 AND VCC2 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.
1510I
15105
15105I
S8 PART MARKING
1510
1510I
Consult factory for Military grade parts.
ELECTRICAL CHARACTERISTICS
VCC = 16V, VBAT = 8V, VMAX (maximum operating VCC) = 28V, no load on any outputs, unless otherwise noted. (Notes 7, 8)
PARAMETER
Overall
CONDITIONS
MIN
TYP
MAX
UNITS
Supply Current
V
PROG
V
PROG
= 2.7V, V ≤ 20V
●
●
2.90
2.91
4.3
4.5
mA
mA
CC
= 2.7V, 20V < V ≤ V
CC
MAX
DC Battery Current, I
(Note 1)
8V ≤ V ≤ 25V, 0V ≤ V
≤ 20V, T < 0°C
●
●
●
●
●
0.91
0.93
1.35
75
1.09
1.07
1.65
125
A
A
BAT
CC
BAT
J
R
R
R
= 4.93k
1.0
1.5
100
PROG
PROG
PROG
= 3.28k (Note 4)
= 49.3k
A
mA
mA
T < 0°C
70
130
J
V
= 28V, V
PROG
PROG
= 20V
BAT
CC
R
R
= 4.93k
= 49.3k
●
●
0.93
75
1.0
100
1.07
125
A
mA
2
LT1510/LT1510-5
ELECTRICAL CHARACTERISTICS
VCC = 16V, VBAT = 8V, VMAX (maximum operating VCC) = 28V, no load on any outputs, unless otherwise noted.
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
Overall
Minimum Input Operating Voltage
Undervoltage Lockout
●
●
6.2
7
3
7.8
15
V
Reverse Current from Battery (When V Is Not
V
BAT
≤ 20V, 0°C ≤ T ≤ 70°C
µA
CC
J
Connected, V Is Floating)
SW
Boost Pin Current
V
– V
≤ 20V
BOOST
●
●
●
●
0.10
0.25
6
20
30
11
14
µA
µA
mA
mA
CC
BOOST
CC
20V < V – V
≤ 28V
2V ≤ V
8V < V
– V ≤ 8V (Switch ON)
BOOST
BOOST
CC
– V ≤ 25V (Switch ON)
8
CC
Switch
Switch ON Resistance
V
= 10V
CC
I
= 1.5A, V
– V ≥ 2V (Note 4)
●
●
0.3
20
0.5
2.0
Ω
Ω
SW
SW
BOOST
SW
I
= 1A, V
– V < 2V (Unboosted)
BOOST SW
∆I
/∆I During Switch ON
BOOST SW
V
V
= 24V, I ≤ 1A
35
mA/A
BOOST
SW
Switch OFF Leakage Current
= 0V, V ≤ 20V
●
●
2
4
100
200
µA
µA
SW
CC
20V < V ≤ 28V
CC
Maximum V
with Switch ON
for Switch ON
●
V
– 2
CC
V
µA
BAT
PROG
PROG
Minimum I
Minimum I
2
1
4
20
for Switch OFF at V
≤ 1V
●
2.4
mA
PROG
Current Sense Amplifier Inputs (SENSE, BAT)
Sense Resistance (R
)
S1
0.08
0.2
0.12
0.25
Ω
Ω
Total Resistance from SENSE to BAT (Note 3)
BAT Bias Current (Note 5)
V < 0.3V
C
–200
700
–375
1300
µA
µA
C
V > 0.6V
Input Common Mode Limit (Low)
Input Common Mode Limit (High)
Reference
●
●
–0.25
V
V
V
– 2
CC
Reference Voltage (Note 1) S8 Package
Reference Voltage (Note 2) 16-Pin
R
R
= 4.93k, Measured at PROG Pin
= 3.28k, Measured at OVP with
●
2.415
2.453
2.465
2.465
2.515
2.477
V
V
PROG
PROG
VA Supplying I
and Switch OFF
PROG
Reference Voltage Tolerance, 16-Pin Only
8V ≤ V ≤ 28V, 0°C ≤ T ≤ 70°C
●
●
●
2.446
2.441
2.430
2.465
2.480
2.489
2.489
V
V
V
CC
J
8V ≤ V ≤ 28V, 0°C ≤ T ≤ 125°C
CC
J
8V ≤ V ≤ 28V, T < 0°C
CC
J
Oscillator
Switching Frequency
LT1510
LT1510-5
180
440
200
500
220
550
kHz
kHz
Switching Frequency Tolerance
Maximum Duty Cycle
All Conditions of V , Temperature, LT1510
●
●
●
●
170
160
425
400
200
230
230
575
575
kHz
kHz
kHz
kHz
CC
LT1510, T < 0°C
J
LT1510-5
500
LT1510-5, T < 0°C
J
LT1510
●
●
87
90
77
%
%
%
LT1510, T = 25°C (Note 8)
93
81
A
LT1510-5 (Note 9)
3
LT1510/LT1510-5
ELECTRICAL CHARACTERISTICS
VCC = 16V, VBAT = 8V, VMAX (maximum operating VCC) = 28V, no load on any outputs, unless otherwise noted.
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
Current Amplifier (CA2)
Transconductance
V = 1V, I = ±1µA
150
250
550
0.6
µmho
C
VC
Maximum V for Switch OFF
●
V
C
I
Current (Out of Pin)
V ≥ 0.6V
C
100
3
µA
mA
VC
C
V < 0.45V
Voltage Amplifier (VA), 16-Pin Only
Transconductance (Note 2)
Output Current from 100µA to 500µA
0.5
1.3
1.2
50
2.5
mho
mA
nA
Output Source Current, V = 10V
V
PROG
= V
= V
+ 10mV
CC
OVP
REF
OVP Input Bias Current
At 0.75mA VA Output Current
●
150
The
●
denotes specifications which apply over the specified
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.
temperature range.
Note 1: Tested with Test Circuit 1.
Note 2: Tested with Test Circuit 2.
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 3: Sense resistor R and package bond wires.
Note 4: Applies to 16-pin only. 8-pin packages are guaranteed but not
tested at –40°C.
S1
Note 5: Current (≈ 700µA) flows into the pins during normal operation and
also when an external shutdown signal on the V pin is greater than 0.3V.
C
Current decreases to ≈ 200µA and flows out of the pins when external
shutdown holds the V pin below 0.3V. Current drops to near zero when
C
Note 8: Industrial grade device specifications are guaranteed over the
–40°C to 85°C temperature range.
input voltage collapses. See external Shutdown in Applications Information
section.
Note 9: 91% maximum duty cycle is guaranteed by design if V
or V
BAT
X
Note 6: A linear interpolation can be used for reference voltage
specification between 0°C and –40°C.
(see Figure 8 in Application Information) is kept between 3V and 5V.
Note 10: V
= 4.2V.
BAT
W
U
TYPICAL PERFORMANCE CHARACTERISTICS
Thermally Limited Maximum
Charging Current, 8-Pin SO
Thermally Limited Maximum
Charging Current, 16-Pin SO
Thermally Limited Maximum
Charging Current, 16-Pin GN
1.5
1.3
1.1
0.9
0.7
0.5
1.3
1.1
0.9
0.7
0.5
0.3
1.5
1.3
1.1
0.9
0.7
0.5
(θ =125°C/W)
JA
AMAX
JMAX
T
T
=60°C
=125°C
4V BATTERY
8V BATTERY
4V BATTERY
4V BATTERY
12V BATTERY
16V BATTERY
8V BATTERY
8V BATTERY
12V BATTERY
12V BATTERY
16V BATTERY
(θ =50°C/W)
JA
AMAX
JMAX
θ
T
T
= 80°C/W
AMAX
JMAX
JA
T
T
=60°C
=125°C
= 60°C
= 125°C
16V BATTERY
15
20
INPUT VOLTAGE (V)
0
5
10
15
20
25
0
5
10
15
20
25
0
5
10
25
INPUT VOLTAGE (V)
INPUT VOLTAGE (V)
1510 G12
1510 G13
LT1510 • TPC14
4
LT1510/LT1510-5
W
U
TYPICAL PERFORMANCE CHARACTERISTICS
Switching Frequency vs
Temperature
Efficiency of Figure 2 Circuit
ICC vs Duty Cycle
100
98
96
94
92
90
88
86
84
82
80
8
7
6
5
4
3
2
1
0
210
205
200
195
190
185
180
V
CC
= 16V
V
= 15V (EXCLUDING DISSIPATION
CC
ON INPUT DIODE D3)
= 8.4V
V
BAT
0°C
125°C
25°C
40
10 20 30
DUTY CYCLE (%)
100
120 140
0.1
0.9 1.1
(A)
1.3 1.5
0
50 60 70 80
–20
0
20 40 60 80
0.3
0.5 0.7
TEMPERATURE (°C)
I
BAT
1510 G01
1510 G04
1510 G05
ICC vs VCC
VREF Line Regulation
IVA vs ∆VOVP (Voltage Amplifier)
7.0
6.5
6.0
5.5
5.0
4.5
4
3
2
1
0
0.003
MAXIMUM DUTY CYCLE
0.002
0.001
0
0°C
25°C
ALL TEMPERATURES
125°C
125°C
25°C
–0.001
–0.002
–0.003
0
10
15
(V)
20
25
30
5
0
10
15
(V)
20
25
30
5
0
0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
(mA)
V
V
CC
I
VA
CC
1510 G03
1510 G02
1510 G08
Maximum Duty Cycle
VC Pin Characteristic
PROG Pin Characteristic
98
97
96
95
94
93
92
91
90
–1.20
–1.08
–0.96
–0.84
–0.72
–0.60
–0.48
–0.36
–0.24
–0.12
0
6
0
125°C
25°C
–6
0.12
20
40
60
80 100
140
0
0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0
(V)
0
120
0
1
2
3
4
5
V
C
TEMPERATURE (°C)
V
(V)
PROG
1510 G10
1510 G09
1510 G11
5
LT1510/LT1510-5
W
U
TYPICAL PERFORMANCE CHARACTERISTICS
Switch Current vs Boost Current
vs Boost Voltage
Reference Voltage vs
Temperature
VBOOST vs
Maximum Duty Cycle
50
45
40
35
30
25
20
15
10
5
2.470
2.468
2.466
2.464
2.462
2.460
2.458
96
95
94
93
92
91
90
89
88
87
86
V
CC
= 16V
V
= 38V
28V
18V
BOOST
0
0
0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0
0
50
75
100
125
150
25
2
4
6
8
10 12 14
22
16 18 20
TEMPERATURE (°C)
SWITCH CURRENT (A)
V
(V)
BOOST
1510 G07
1510 G14
LT1510 • TPC15
U
U
U
PIN FUNCTIONS
GND: Ground Pin.
BAT: Current Amplifier CA1 Input.
SW: Switch Output. The Schottky catch diode must be
placedwithveryshortleadlengthincloseproximitytoSW
pin and GND.
PROG: This pin is for programming the charging current
and for system loop compensation. During normal opera-
tion, VPROG stays close to 2.465V. If it is shorted to GND
theswitchingwillstop. Whenamicroprocessor-controlled
DAC is used to program charging current, it must be
capable of sinking current at a compliance up to 2.465V.
VCC: Supply for the Chip. For good bypass, a low ESR
capacitorof10µForhigherisrequired,withtheleadlength
kept to a minimum. VCC should be between 8V and 28V
andatleast2VhigherthanVBAT forVBAT lessthan10V,and
2.5V higher than VBAT for VBAT greater than 10V. Under-
voltage lockout starts and switching stops when VCC goes
below 7V. Note that there is a parasitic diode inside from
SW pin to VCC pin. Do not force VCC below SW by more
than 0.7V with battery present. All VCC pins should be
shorted together close to the pins.
VC:Thisisthecontrolsignaloftheinnerloopofthecurrent
mode PWM. Switching starts at 0.7V and higher VC
corresponds to higher charging current in normal opera-
tion. A capacitor of at least 0.1µF to GND filters out noise
and controls therate of soft start. To shut down switching,
pull this pin low. Typical output current is 30µA.
OVP: This is the input to the amplifier VA with a threshold
of2.465V. Typicalinputcurrentisabout50nAintopin. For
charging lithium-ion batteries, VA monitors the battery
voltage and reduces charging current when battery volt-
age reaches the preset value. If it is not used, the OVP pin
should be grounded.
BOOST: This pin is used to bootstrap and drive the switch
power NPN transistor to a low on-voltage for low power
dissipation. In normal operation, VBOOST = VCC + VBAT
when switch is on. Maximum allowable VBOOST is 55V.
SENSE: Current Amplifier CA1 Input. Sensing can be at
either terminal of the battery. Note that current sense
resistor RS1 (0.08Ω) is between Sense and BAT pins.
6
LT1510/LT1510-5
W
BLOCK DIAGRAM
200kHz
OSCILLATOR
V
+
–
CC
SHUTDOWN
0.7V
+
BOOST
S
V
SW
–
+
V
CC
Q
SW
R
R
SW
–
+
1.5V
SLOPE
COMPENSATION
B1
+
SENSE
GND
I
PROG
PWM
+
V
BAT
I
CA1
R
S1
BAT
C1
R2
R3
+
–
BAT
0VP
–
I
PROG
R1
1k
= 500µA/A
I
BAT
+
–
–
+
VA
V
REF
V
C
CA2
2.465V
Ω
60k
g
= 0.64
V
m
REF
PROG
CHARGING CURRENT I
PROG
BAT
1510 BD
R
PROG
= (I
)(2000)
C
PROG
I
2.465V
PROG
PROG
=
(2000)
(
)
R
TEST CIRCUITS
Test Circuit 1
LT1510
SENSE
I
BAT
+
–
–
+
CA1
R
S1
BAT
V
C
CA2
+
1k
+
V
BAT
60k
56µF
0.047µF
V
REF
PROG
0.22µF
3.3k
R
PROG
+
LT1006
LT1010
2N3055
1k
–
1k
+
≈ 0.65V
20k
1510 TC01
7
LT1510/LT1510-5
TEST CIRCUITS
Test Circuit 2
LT1510
OVP
+
VA
–
V
REF
PROG
10k
10k
I
PROG
–
LT1013
+
+
0.47µF
R
PROG
2.465V
1510 TC02
U
OPERATIO
The LT1510 is a current mode PWM step-down (buck)
switcher. The battery DC charging current is programmed
by a resistor RPROG (or a DAC output current) at the PROG
pin (see Block Diagram). Amplifier CA1 converts the
charging current through RS1 to a much lower current
IPROG (500µA/A) fed into the PROG pin. Amplifier CA2
compares the output of CA1 with the programmed current
and drives the PWM loop to force them to be equal. High
level shift resistors R2 and R3, forming the current mode
inner loop. The Boost pin drives the switch NPN QSW into
saturation and reduces power loss. For batteries like
lithium-ion that require both constant-current and con-
stant-voltage charging, the 0.5%, 2.465V reference and
the amplifier VA reduce the charging current when battery
voltage reaches the preset level. For NiMH and NiCd, VA
can be used for overvoltage protection. When input volt-
age is not present, the charger goes into low current (3µA
typically) sleep mode as input drops down to 0.7V below
battery voltage. To shut down the charger, simply pull the
VC pin low with a transistor.
DC accuracy is achieved with averaging capacitor CPROG
.
Note that IPROG has both AC and DC components. IPROG
goes through R1 and generates a ramp signal that is fed to
the PWM control comparator C1 through buffer B1 and
U
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APPLICATIONS INFORMATION
tantalum capacitors such as the AVX TPS and Sprague
593D series have high ripple current rating in a relatively
small surface mount package, but caution must be used
when tantalum capacitors are used for input bypass. High
input surge currents can be created when the adapter is
hot-plugged to the charger and solid tantalum capacitors
have a known failure mechanism when subjected to very
high turn-on surge currents. Highest possible voltage
rating on the capacitor will minimize problems. Consult with
the manufacturer before use. Alternatives include new high
Application Note 68, the LT1510 design manual, contains
more in depth appications examples.
Input and Output Capacitors
In the chargers in Figures 1 and 2 on the first page of this
datasheet, theinputcapacitorCIN isassumedtoabsorball
input switching ripple current in the converter, so it must
have adequate ripple current rating. Worst-case RMS
ripple current will be equal to one half of output charging
current. Actual capacitance value is not critical. Solid
8
LT1510/LT1510-5
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APPLICATIONS INFORMATION
capacity ceramic capacitor (5µF to 10µF) from Tokin or
United Chemi-Con/MARCON, et al., and the old standby,
aluminum electrolytic, which will require more microfarads
to achieve adequate ripple rating. OS-CON can also be used.
deliver full power to the load when the input voltage is still
well below its final value. If the adapter is current limited,
it cannot deliver full power at reduced output voltages and
the possibility exists for a quasi “latch” state where the
adapter output stays in a current limited state at reduced
output voltage. For instance, if maximum charger plus
computer load power is 20W, a 24V adapter might be
current limited at 1A. If adapter voltage is less than (20W/1A
= 20V) when full power is drawn, the adapter voltage will be
sucked down by the constant 20W load until it reaches a
lower stable state where the switching regulators can no
longer supply full load. This situation can be prevented by
utilizing undevoltage lockout, set higher than the minimum
adapter voltage where full power can be achieved.
The output capacitor COUT is also assumed to absorb
output switching current ripple. The general formula for
capacitor current is:
VBAT
VCC
0.29 V
1−
(
)
BAT
IRMS
=
L1 f
( )( )
For example, with VCC = 16V, VBAT = 8.4V, L1 = 30µH and
f = 200kHz, IRMS = 0.2A.
A fixed undervoltage lockout of 7V is built into the VCC pin.
Internal lockout is performed by clamping the VC pin low.
The VC pin is released from its clamped state when the VCC
pinrisesabove7V.Thechargerwillstartdeliveringcurrent
about 2ms after VC is released, as set by the 0.1µF at VC
pin. Higher lockout voltage can be implemented with a
Zener diode (see Figure 3 circuit).
EMI considerations usually make it desirable to minimize
ripple current in the battery leads, and beads or inductors
maybeaddedtoincreasebatteryimpedanceatthe200kHz
switching frequency. Switching ripple current splits be-
tween the battery and the output capacitor depending on
theESRoftheoutputcapacitorandthebatteryimpedance.
If the ESR of COUT is 0.2Ω and the battery impedance is
raisedto4Ωwithabeadofinductor,only5%ofthecurrent
ripple will flow in the battery.
V
IN
V
D1
1N4001
V
Z
CC
Soft Start
V
LT1510
GND
C
The LT1510 is soft started by the 0.1µF capacitor on VC
pin. On start-up, VC pin voltage will rise quickly to 0.5V,
then ramp at a rate set by the internal 45µA pull-up current
and the external capacitor. Battery charging current starts
ramping up when VC voltage reaches 0.7V and full current
is achieved with VC at 1.1V. With a 0.1µF capacitor, time to
reach full charge current is about 3ms and it is assumed
that input voltage to the charger will reach full value in less
than 3ms. Capacitance can be increased up to 0.47µF if
longer input start-up times are needed.
2k
1510 F03
Figure 3. Undervoltage Lockout
The lockout voltage will be VIN = VZ + 1V.
For example, for a 24V adapter to start charging at 22VIN,
choose VZ = 21V. When VIN is less than 22V, D1 keeps VC
low and charger off.
Charging Current Programming
In any switching regulator, conventional timer-based soft
starting can be defeated if the input voltage rises much
slowerthanthetime-outperiod.Thishappensbecausethe
switching regulators in the battery charger and the com-
puter power supply are typically supplying a fixed amount
of power to the load. If input voltage comes up slowly
compared to the soft start time, the regulators will try to
The basic formula for charging current is (see Block
Diagram):
2.465V
RPROG
IBAT = I
2000 =
2000
(
PROG)(
)
(
)
9
LT1510/LT1510-5
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APPLICATIONS INFORMATION
even this low current drain. A 47k resistor from adapter
output to ground should be added if Q3 is used to ensure
that the gate is pulled to ground.
where RPROG is the total resistance from PROG pin to
ground.
For example, 1A charging current is needed.
With divider current set at 25µA, R4 = 2.465/25µA = 100k
and,
2.465V 2000
(
)(
)
RPROG
=
= 4.93k
1A
R4 V − 2.465
100k 8.4 − 2.465
( )(
)
(
)
BAT
R3 =
=
Charging current can also be programmed by pulse width
modulatingIPROG withaswitchQ1toRPROG atafrequency
higher than a few kHz (Figure 4). Charging current will be
proportionaltothedutycycleoftheswitchwithfullcurrent
at 100% duty cycle.
2.465 +R4 0.05µA 2.465 +100k 0.05µA
(
)
(
)
= 240k
Lithium-ion batteries typically require float voltage accu-
racy of 1% to 2%. Accuracy of the LT1510 OVP voltage is
±0.5% at 25°C and ±1% over full temperature. This leads
tothepossibilitythatveryaccurate(0.1%)resistorsmight
be needed for R3 and R4. Actually, the temperature of the
LT1510 will rarely exceed 50°C in float mode because
chargingcurrentshavetaperedofftoalowlevel, so0.25%
resistors will normally provide the required level of overall
accuracy.
When a microprocessor DAC output is used to control
charging current, it must be capable of sinking current
at a compliance up to 2.5V if connected directly to the
PROG pin.
LT1510
PROG
300Ω
External Shutdown
R
C
PROG
PROG
4.64k
1µF
The LT1510 can be externally shut down by pulling the VC
pin low with an open drain MOSFET, such as VN2222. The
VC pin should be pulled below 0.8V at room temperature
to ensure shutdown. This threshold decreases at about
2mV/°C. A diode connected between the MOSFET drain
and the VC pin will still ensure the shutdown state over all
temperatures, but it results in slightly different conditions
as outlined below.
Q1
5V
0V
VN2222
PWM
I
= (DC)(1A)
BAT
1510 F04
Figure 4. PWM Current Programming
Lithium-Ion Charging
The circuit in Figure 2 uses the 16-pin LT1510 to charge
lithium-ion batteries at a constant 1.3A until battery volt-
age reaches a limit set by R3 and R4. The charger will then
automatically go into a constant-voltage mode with cur-
rentdecreasingtozeroovertimeasthebatteryreachesfull
charge. This is the normal regimen for lithium-ion charg-
ing, with the charger holding the battery at “float” voltage
indefinitely. In this case no external sensing of full charge
is needed.
If the VC pin is held below threshold, but above ≈ 0.4V, the
current flowing into the BAT pin will remain at about
700µA.PullingtheVC pinbelow0.4Vwillcausethecurrent
todropto ≈200µAandreverse, flowingout oftheBATpin.
Although these currents are low, the long term effect may
need to be considered if the charger is held in a shutdown
state for very long periods of time, with the charger input
voltage remaining. Removing the charger input voltage
causes all currents to drop to near zero.
Current through the R3/R4 divider is set at a compromise
value of 25µA to minimize battery drain when the charger
isoffandtoavoidlargeerrorsduetothe50nAbiascurrent
of the OVP pin. Q3 can be added if it is desired to eliminate
If it is acceptable to have 200µA flowing into the battery
while the charger is in shutdown, simply pull the VC pin
directly to ground with the external MOSFET. The resistor
divider used to sense battery voltage will pull current out
10
LT1510/LT1510-5
U
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APPLICATIONS INFORMATION
of the battery, canceling part or all of the 200µA. Note that
if net current is into the battery and the battery is removed,
the charger output voltage will float high, to near input
voltage. This could be a problem when reinserting the
battery, if the resulting output capacitor/battery surge
current is high enough to damage either the battery or the
capacitor.
period, after which the LT1510 can be shut down by
pulling the VC pin low with an open collector or drain.
Some external means must be used to detect the need for
additional charging if needed, or the charger may be
turned on periodically to complete a short float-voltage
cycle.
Current trip level is determined by the battery voltage, R1
through R3, and the internal LT1510 sense resistor
(≈ 0.18Ω pin-to-pin). D2 generates hysteresis in the trip
level to avoid multiple comparator transitions.
If net current into the battery must be less than zero in
shutdown, there are several options. Increasing divider
current to 300µA - 400µA will ensure that net battery
current is less than zero. For long term storage conditions
however, the divider may need to be disconnected with a
MOSFET switch as shown in Figures 2 and 5. A second
option is to connect a 1N914 diode in series with the
MOSFET drain. This will limit how far the VC pin will be pulled
down, and current (≈ 700µA) will flow into the BAT pin, and
therefore out of the battery. This is not usually a problem
unless the charger will remain in the shutdown state with
input power applied for very long periods of time.
Nickel-Cadmium and Nickel-Metal-Hydride Charging
The circuit in Figure 6 uses the 8-pin LT1510 to charge
NiCd or NiMH batteries up to 12V with charging currents
of 0.5A when Q1 is on and 50mA when Q1 is off.
D3
1N5819
C1
0.22µF
D1
1N5819
SW
V
CC
+
C
*
IN
WALL
ADAPTER
10µF
Removing input power to the charger will cause the BAT
pin current to drop to near zero, with only the divider
current remaining as a small drain on the battery. Even
that current can be eliminated with a switch as shown in
Figures 2 and 5.
BOOST PROG
LT1510
1µF
L1**
33µH
R1
300Ω
100k
D2
1N914
R2
11k
0.1µF
GND
V
C
1k
Q1
VN2222
I
BAT
SENSE
BAT
ON: I
= 0.5A
BAT
BAT
+
+
OFF: I
= 0.05A
C
2V TO
20V
OUT
*
TOKIN OR MARCON CERAMIC
SURFACE MOUNT
** COILTRONICS CTX33-2
22µF
V
BAT
+
TANT
1510 F05.5
R3
4.2V
4.2V
12k
–
+
R5
220k
Figure 6. Charging NiMH or NiCd Batteries
(Efficiency at 0.5A ≈ 90%)
Q3
VN2222
LT1510
OVP
–
V
IN
R4
4.99k
0.25%
For a 2-level charger, R1 and R2 are found from:
1510 F05
2000 2.465
(
)(
)
Figure 5. Disconnecting Voltage Divider
IBAT
=
(
RPROG
Some battery manufacturers recommend termination of
constant-voltage float mode after charging current has
droppedbelowaspecifiedlevel(typically50mAto100mA)
and a further time-out period of 30 minutes to 90 minutes
has elapsed. This may extend the life of the battery, so
check with manufacturers for details. The circuit in Figure
7 will detect when charging current has dropped below
75mA. This logic signal is used to initiate a time-out
2.465 2000
2.465 2000
)(
)
(
)(
)
R1=
R2 =
ILOW
IHI −ILOW
All battery chargers with fast-charge rates require some
meanstodetectfullchargestateinthebatterytoterminate
the high charging current. NiCd batteries are typically
charged at high current until temperature rise or battery
11
LT1510/LT1510-5
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BAT
ADAPTER
OUTPUT
0.18Ω
SENSE
3.3V OR 5V
INTERNAL
D1
8
C1
R1*
SENSE
1N4148
0.1µF
R4
470k
1.6k
RESISTOR
LT1510
3
2
–
7
NEGATIVE EDGE
TO TIMER
LT1011
GND
+
4
1
R2
560k
D2
1N4148
R1(V
(R2 + R3)(0.18Ω)
)
R3
430k
BAT
* TRIP CURRENT =
1510 F06
Figure 7. Current Comparator for Initiating Float Time-Out
battery and 1.1A for a 4.2V battery. This assumes a 60°C
maximum ambient temperature. The 16-pin SO, with a
thermal resistance of 50°C/W, can provide a full 1.5A
charging current in many situations. The 16-pin PDIP falls
between these extremes. Graphs are shown in the Typical
Performance Characteristics section.
voltage decrease is detected as an indication of near full
charge. The charging current is then reduced to a much
lower value and maintained as a constant trickle charge.
An intermediate “top off” current may be used for a fixed
time period to reduce 100% charge time.
NiMH batteries are similar in chemistry to NiCd but have
two differences related to charging. First, the inflection
characteristic in battery voltage as full charge is ap-
proached is not nearly as pronounced. This makes it more
difficult to use dV/dt as an indicator of full charge, and
change of temperature is more often used with a tempera-
ture sensor in the battery pack. Secondly, constant trickle
charge may not be recommended. Instead, a moderate
level of current is used on a pulse basis (≈ 1% to 5% duty
cycle) with the time-averaged value substituting for a
constant low trickle.
PBIAS = 3.5mA V +1.5mA V
(
)(
)
IN
(
)
BAT
2
)
V
(
BAT
+
7.5mA + 0.012 I
(
)( BAT
)
]
[
V
IN
2
)
VBAT
30
I
(
V
1+
BAT)(
BAT
PDRIVER
=
55 V
(
)
)
IN
2
I
R
V
(
BAT) ( SW)(
BAT
Thermal Calculations
PSW
P
=
+ t
(
V I
f
OL)( IN)( BAT)( )
V
IN
If the LT1510 is used for charging currents above 0.4A, a
thermal calculation should be done to ensure that junction
temperature will not exceed 125°C. Power dissipation in
the IC is caused by bias and driver current, switch resis-
tance, switch transition losses and the current sense
resistor. The following equations show that maximum
practical charging current for the 8-pin SO package
(125° C/W thermal resistance) is about 0.8A for an 8.4V
2
= 0.18Ω I
(
)( BAT
)
SENSE
RSW = Switch ON resistance ≈ 0.35Ω
tOL = Effective switch overlap time ≈ 10ns
f = 200kHz (500kHz for LT1510-5)
12
LT1510/LT1510-5
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Example: VIN = 15V, VBAT = 8.4V, IBAT = 1.2A;
PBIAS = 3.5mA 15 +1.5mA 8.4
The average IVX required is:
P
0.045W
3.3V
DRIVER
(
)( )
(
)
=
= 14mA
VX
8.4 2
(
)
Total board area becomes an important factor when the
areaoftheboarddropsbelowabout20squareinches. The
graph in Figure 9 shows thermal resistance vs board area
for 2-layer and 4-layer boards. Note that 4-layer boards
havesignificantlylowerthermalresistance, butbothtypes
show a rapid increase for reduced board areas. Figure 10
shows actual measured lead temperature for chargers
operating at full current. Battery voltage and input voltage
will affect device power dissipation, so the data sheet
power calculations must be used to extrapolate these
readings to other situations.
+
7.5mA + 0.012 1.2 = 0.17W
(
)(
)
]
[
15
1.2 8.4 2 1+
8.4
(
)(
)
30
P
=
= 0.13W
DRIVER
55 15
( )
2
1.2 0.35 8.4
(
) (
)(
)
P
=
+
SW
15
−9
10 •10
15 1.2 200kHz
( )( )(
)
= 0.28 + 0.04 = 0.32W
Vias should be used to connect board layers together.
Planes under the charger area can be cut away from the
rest of the board and connected with vias to form both a
2
)
P
= 0.18 1.2 = 0.26W
(
)(
SENSE
Total power in the IC is:
SW
0.17 + 0.13 + 0.32+ 0.26 = 0.88W
LT1510
C1
D2
BOOST
L1
Temperature rise will be (0.88W)(50°C/W) = 44°C. This
assumes that the LT1510 is properly heat sunk by con-
necting the four fused ground pins to the expanded traces
and that the PC board has a backside or internal plane for
heat spreading.
SENSE
V
X
1510 F07
+
I
VX
10µF
Figure 8
The PDRIVER term can be reduced by connecting the boost
diode D2 (see Figures 2 and 6 circuits) to a lower system
voltage (lower than VBAT) instead of VBAT (see Figure 8).
60
55
50
45
40
35
30
25
Then,
2-LAYER BOARD
4-LAYER BOARD
VX
30
I
V
V
1+
(
BAT)( BAT)( )
X
PDRIVER
=
55 V
(
)
IN
S16, MEASURED FROM AIR AMBIENT
TO DIE USING COPPER LANDS AS
SHOWN ON DATA SHEET
For example, VX = 3.3V,
20
BOARD AREA (IN2)
25
30
35
0
5
10
15
3.3V
30
1.2A 8.4V 3.3V 1+
(
)(
)(
)
)
1510 F08
PDRIVER
=
= 0.045W
Figure 9. LT1510 Thermal Resistance
55 15V
(
13
LT1510/LT1510-5
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APPLICATIONS INFORMATION
90
event of an input short. The body diode of Q2 creates the
necessary pumping action to keep the gate of Q1 low
during normal operation (see Figure 11).
NOTE: PEAK DIE TEMPERATURE WILL BE
ABOUT 10°C HIGHER THAN LEAD TEMPER-
80
ATURE AT 1.3A CHARGING CURRENT
70
2-LAYER BOARD
60
Q1
V
IN
+
4-LAYER BOARD
50
40
30
20
V
CC
I
= 1.3A
CHRG
IN
BAT
SW
V
V
V
= 16V
Q2
LT1510
C3
D2
= 8.4V
= V
R
X
BOOST
BOOST
= 25°C
BAT
D1
L1
50k
T
A
0
5
10
15
20
BOARD AREA (IN2)
25
30
35
SENSE
V
1510 F09
X
BAT
3V TO 6V
C
X
V
BAT
Figure 10. LT1510 Lead temperature
10µF
Q1: Si4435DY
Q2: TP0610L
+
low thermal resistance system and to act as a ground
plane for reduced EMI.
HIGH DUTY CYCLE
CONNECTION
1510 F10
Figure 11. Replacing the Input Diode
Higher Duty Cycle for the LT1510 Battery Charger
Layout Considerations
Maximum duty cycle for the LT1510 is typically 90% but
this may be too low for some applications. For example, if
an 18V ±3% adapter is used to charge ten NiMH cells, the
charger must put out 15V maximum. A total of 1.6V is lost
in the input diode, switch resistance, inductor resistance
and parasitics so the required duty cycle is 15/16.4 =
91.4%. As it turns out, duty cycle can be extended to 93%
by restricting boost voltage to 5V instead of using VBAT as
is normally done. This lower boost voltage VX (see Figure
8) also reduces power dissipation in the LT1510, so it is a
win-win decision.
Switch rise and fall times are under 10ns for maximum
efficiency. To prevent radiation, the catch diode, SW pin
and input bypass capacitor leads should be kept as short
as possible. A ground plane should be used under the
switching circuitry to prevent interplane coupling and to
act as a thermal spreading path. All ground pins should be
connected to expand traces for low thermal resistance.
The fast-switching high current ground path including the
switch, catch diode and input capacitor should be kept
very short. Catch diode and input capacitor should be
close to the chip and terminated to the same point. This
path contains nanosecond rise and fall times with several
amps of current. The other paths contain only DC and /or
200kHz triwave and are less critical. Figure 13 shows
critical path layout. Figure 12 indicates the high speed,
high current switching path.
Even Lower Dropout
Forevenlowerdropoutand/orreducingheatontheboard,
the input diode D3 (Figures 2 and 6) should be replaced
with a FET. It is pretty straightforward to connect a
P-channel FET across the input diode and connect its gate
to the battery so that the FET commutates off when the
input goes low. The problem is that the gate must be
pumped low so that the FET is fully turned on even when
the input is only a volt or two above the battery voltage.
Alsothereisaturnoffspeedissue. TheFETshouldturnoff
instantly when the input is dead shorted to avoid large
current surges form the battery back through the charger
into the FET. Gate capacitance slows turn off, so a small
P-FET (Q2) discharges the gate capacitance quickly in the
SWITCH NODE
L1
V
BAT
HIGH
FREQUENCY
CIRCULATING
PATH
C
C
OUT
V
IN
BAT
IN
1510 F12
Figure 12. High Speed Switching Path
14
LT1510/LT1510-5
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APPLICATIONS INFORMATION
GND
LT1510
GND
D1
GND
C
IN
SW
V
V
CC2
CC1
BOOST
GND
PROG
OVP
V
C
L1
SENSE
GND
BAT
GND
GND
GND
1510 F11
Figure 13. Critical Electrical and Thermal Path Layer
U
PACKAGE DESCRIPTION Dimensions in inches (millimeters) unless otherwise noted.
0.189 – 0.196*
GN Package
(4.801 – 4.978)
16-Lead Plastic SSOP (Narrow 0.150)
16 15 14 13 12 11 10
9
(LTC DWG # 05-08-1641)
0.015 ± 0.004
(0.38 ± 0.10)
× 45° 0.053 – 0.069
0.004 – 0.009
(0.102 – 0.249)
0.229 – 0.244
(5.817 – 6.198)
0.150 – 0.157**
(3.810 – 3.988)
(1.351 – 1.748)
0.0075 – 0.0098
(0.191 – 0.249)
0° – 8° TYP
0.016 – 0.050
(0.406 – 1.270)
0.008 – 0.012
(0.203 – 0.305)
0.025
(0.635)
BSC
1
2
3
4
5
6
7
8
*
DIMENSION DOES NOT INCLUDE MOLD FLASH. MOLD FLASH
SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE
GN16 (SSOP) 0895
** DIMENSION DOES NOT INCLUDE INTERLEAD FLASH. INTERLEAD
FLASH SHALL NOT EXCEED 0.010" (0.254mm) PER SIDE
N Package
16-Lead PDIP (Narrow 0.300)
(LTC DWG # 05-08-1510)
0.770*
(19.558)
MAX
0.300 – 0.325
0.130 ± 0.005
0.045 – 0.065
(1.143 – 1.651)
(7.620 – 8.255)
(3.302 ± 0.127)
14
12
10
9
15
13
11
16
0.015
(0.381)
MIN
0.255 ± 0.015*
(6.477 ± 0.381)
0.065
(1.651)
TYP
0.009 – 0.015
(0.229 – 0.381)
+0.025
0.325
0.005
(0.127)
MIN
0.100 ± 0.010
(2.540 ± 0.254)
–0.015
0.125
(3.175)
MIN
2
1
3
4
6
8
5
7
0.018 ± 0.003
+0.635
8.255
(0.457 ± 0.076)
(
)
–0.381
*THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS.
MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.010 INCH (0.254mm)
N16 0695
S8 Package
0.189 – 0.197*
(4.801 – 5.004)
8-Lead Plastic Small Outline (Narrow 0.150)
7
5
8
6
(LTC DWG # 05-08-1610)
0.228 – 0.244
(5.791 – 6.197)
0.010 – 0.020
(0.254 – 0.508)
× 45°
0.053 – 0.069
(1.346 – 1.752)
0.150 – 0.157**
(3.810 – 3.988)
0.004 – 0.010
(0.101 – 0.254)
0.008 – 0.010
(0.203 – 0.254)
0°– 8° TYP
0.016 – 0.050
0.406 – 1.270
0.050
(1.270) BSC
0.014 – 0.019
(0.355 – 0.483)
1
2
3
4
*DIMENSION DOES NOT INCLUDE MOLD FLASH. MOLD FLASH SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE
**DIMENSION DOES NOT INCLUDE INTERLEAD FLASH. INTERLEAD FLASH SHALL NOT EXCEED 0.010" (0.254mm) PER SIDE
SO8 0695
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-
tationthattheinterconnectionofitscircuitsasdescribedhereinwillnotinfringeonexistingpatentrights.
15
LT1510/LT1510-5
TYPICAL APPLICATION
U
Adjustable Voltage Regulator with Precision Adjustable Current Limit
LT1510
0.22µF
1N5819
V
IN
SW
V
CC2
18V TO 25V
+
100µF
V
CC1
BOOST
PROG
R
PROG
4.93k
1k
30µH
V
C
0.01µF
GND
1N914
0.1µF
POT
100k
OVP
1µF
V
SENSE
BAT
OUT
2.5V TO 15V
+
POT
5k
CURRENT LIMIT LEVEL
50mA TO 1A
500µF
2.465V
PROG
1k
CURRENT LIMIT LEVEL =
(2000)
(
)
R
1510 TA01
U
PACKAGE DESCRIPTION
Dimensions in inches (millimeters) unless otherwise noted.
S Package
16-Lead Plastic Small Outline (Narrow 0.150)
(LTC DWG # 05-08-1610)
0.386 – 0.394*
(9.804 – 10.008)
16
15
14
13
12
11
10
9
0.004 – 0.010
(0.101 – 0.254)
0.053 – 0.069
0.010 – 0.020
× 45°
0.150 – 0.157**
(3.810 – 3.988)
(1.346 – 1.752)
(0.254 – 0.508)
0.008 – 0.010
(0.203 – 0.254)
0.228 – 0.244
(5.791 – 6.197)
0° – 8° TYP
0.050
(1.270)
TYP
0.014 – 0.019
(0.355 – 0.483)
1
2
3
4
5
6
7
8
0.016 – 0.050
0.406 – 1.270
S16 0695
*DIMENSION DOES NOT INCLUDE MOLD FLASH. MOLD FLASH
SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE
**DIMENSION DOES NOT INCLUDE INTERLEAD FLASH. INTERLEAD
FLASH SHALL NOT EXCEED 0.010" (0.254mm) PER SIDE
RELATED PARTS
PART NUMBER
DESCRIPTION
COMMENTS
LTC®1325
Microprocessor-Controlled Battery Management
System
Can Charge, Discharge and Gas Gauge NiCd, NiMH and Pb-Acid
Batteries with Software Charging Profiles
LT1372/LT1377
LT1373
500kHz/1MHz Step-Up Switching Regulators
250kHz Step-Up Switching Regulator
High Frequency, Small Inductor, High Efficiency Switchers, 1.5A Switch
High Efficiency, Low Quiescent Current, 1.5A Switch
LT1376
500kHz Step-Down Switching Regulator
High Frequency, Small Inductor, High Efficiency Switcher, 1.5A Switch
LT1511
3A Constant-Voltage/Constant-Current Battery Charger
High Efficiency, Minimal External Components to Fast Charge Lithium,
NiMH and NiCd Batteries
LT1512
SEPIC Battery Charger
V Can Be Higher or Lower Than Battery Voltage
IN
1510fc LT/GP 1197 REV C 4K • PRINTED IN USA
16 Linear Technology Corporation
●
1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408)432-1900
●
●
FAX: (408) 434-0507 TELEX: 499-3977 www.linear-tech.com
LINEAR TECHNOLOGY CORPORATION 1995
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