LT1510CS8 Linear Technology, LT1510CS8 Datasheet - Page 13

• Manufacturer Part Number: LT1510CS8
• Description: IC BATT CHARGER CONST V/I 8SOIC
• Manufacturer: Linear Technology

Specifications of LT1510CS8

• Function: Charge Management
• Battery Type: Li-Ion, NiCd, NiMH
• Voltage - Supply: 6.2 V ~ 28 V
• Operating Temperature: 0°C ~ 70°C
• Mounting Type: Surface Mount
• Package / Case: 8-SOIC (0.154", 3.90mm Width)
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

APPLICATIONS
Example: V
Total power in the IC is:
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.
The P
diode D2 (see Figures 2 and 6 circuits) to a lower system
voltage (lower than V
Then,
For example, V
P
P
P
P
0.17 + 0.13 + 0.32+ 0.26 = 0.88W
P
P
DRIVER
BIAS
SW
SENSE
DRIVER
DRIVER
DRIVER
8 4
15
0 28 0 04 0 32
2
1 2
.
IN
3 5
10 10
7 5
.
term can be reduced by connecting the boost
= 15V, V
0 18 1 2
1 2 8 4
I
1 2
mA
•
BAT
X
.
2
mA
= 3.3V,
0 35 8 4
A
15
.
.
U
15
V
55 15
9
8 4
BAT
BAT
.
55
BAT
0 012 1 2
2
15 1 2 200
V
2
55 15
INFORMATION
) instead of V
.
1
1 5
.
U
V
= 8.4V, I
V
IN
3 3
X
0 26
mA
.
W
8 4
30
.
V
V
1
W
8 4
1
30
V
BAT
W
X
0 13
kHz
0 17
3 3
BAT
= 1.2A;
30
V
W
(see Figure 8).
W
U
0 045
W
The average I
Total board area becomes an important factor when the
area of the board drops below about 20 square inches. The
graph in Figure 9 shows thermal resistance vs board area
for 2-layer and 4-layer boards. Note that 4-layer boards
have significantly lower thermal resistance, but both types
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.
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
P
DRIVER
V
X
Figure 9. LT1510 Thermal Resistance
60
55
50
45
40
35
30
25
V
X
VX
0 045
0
I
3 3
VX
S16, MEASURED FROM AIR AMBIENT
TO DIE USING COPPER LANDS AS
SHOWN ON DATA SHEET
required is:
L1
5
V
W
+
10
BOARD AREA (IN
Figure 8
14
D2
10 F
C1
15
mA
LT1510/LT1510-5
4-LAYER BOARD
2-LAYER BOARD
20
SW
BOOST
SENSE
2
25
)
LT1510
1510 F07
30
1510 F08
35
13