LTC4150IMS#PBF Linear Technology, LTC4150IMS#PBF Datasheet - Page 11

• Manufacturer Part Number: LTC4150IMS#PBF
• Description: IC COUNTER/GAUGE GAS/BATT 10MSOP
• Manufacturer: Linear Technology

Specifications of LTC4150IMS#PBF

• Function: Fuel, Gas Gauge/Monitor
• Battery Type: Li-Ion, NiCd, NiMH
• Voltage - Supply: 2.7 V ~ 8.5 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 10-TFSOP, 10-MSOP (0.118", 3.00mm Width)
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

APPLICATIONS INFORMATION
PC BOARD LAYOUT SUGGESTIONS
Keep all traces as short as possible to minimize noise
and inaccuracy. The supply bypass capacitor C2 should
be placed close to the LTC4150. The 4.7μF fi lter capacitor
C
be a low leakage, unpolarized type. Use a 4-wire Kelvin
sense connection for the sense resistor, locating it close
to the LTC4150 with short sense traces to the SENSE
SENSE
and powered load, see Figure 7.
Figure 8 shows a typical application designed for a single
cell lithium-ion battery and 500mA maximum load current.
Use Equation 1 to calculate R
With R
corresponds to 0.085mAh. Equation 14, derived from
Equation 2, gives the number of INT assertions for average
battery current, I
Loading the battery so that 51.5mA is drawn from it over
600 seconds results in 100 INT assertions. For an 800mAh
battery, this is (51.5mA • 1/6h) / 800mAh = 11% of the
battery’s capacity.
TYPICAL APPLICATIONS
F
should be placed close the C
INT Assertions = G
SENSE
–
pins and longer force lines to the battery pack
= 0.1Ω, Equation 7 shows that each interrupt
BATT
, over a time, t, in seconds:
SINGLE-CELL
VF
3.0V ~ 4.2V
• I
R
Li-Ion
BATT
SENSE
0.1Ω
SENSE
+
F
+
• R
4.7μF
Figure 8. Typical Application, Single Cell Lithium-Ion Battery
and C
C
SENSE
F
= 0.05V/0.5A = 0.1Ω.
F
1
2
3
4
5
–
SENSE
SENSE
C
C
SHDN
pins and should
• t
F
F
+
–
LTC4150
+
–
GND
CLR
V
POL
INT
DD
+
(14)
and
10
9
8
7
6
R3
75k
R4
76.8k
SHUTDOWN
C2
4.7μF
With a microcontroller supply = 5V, Equation 11 gives
R
From Equation 12, R
A single cell lithium-ion battery can discharge as low as
2.7V.
From Equation 13, select R1 = 75k; the nearest standard
value for R2 is 76.8k.
Also from Equation 13, we choose R3 = 75k and R4 =
76.8k.
L
> 2.875k. The nearest standard value is 3k.
R
3k
R2
76.8k
R1
75k
L
Figure 7. Kelvin Connection on SENSE Resistor
R
R
3k
SENSE
L
TO CHARGER
5.0V
TO BATTERY
μP
L
C
47μF
L
= 3k gives R1 + R2 equal to 150.5k.
POWER-DOWN
SWITCH
PIN 1
LOAD
4150 F08
LTC4150
LTC4150
4150 F07
11
4150fc