LTC1199 LINER [Linear Technology], LTC1199 Datasheet - Page 26

• Manufacturer Part Number: LTC1199
• Description: 10-Bit, 500ksps ADCs in MSOP with Auto Shutdown
• Manufacturer: LINER [Linear Technology]

LTC1197/LTC1197L
LTC1199/LTC1199L
Battery Current Monitor
The LTC1197L/LTC1199L are ideal for 3V systems. Fig-
ure 14 shows a 2.7V to 4V battery current monitor that
draws only 45 A at 3V from the battery it monitors,
sampling at a 1Hz rate. To minimize supply current, the
microprocessor uses the LTC1152 SHDN pin to turn on
the op amp prior to making a measurement and then turn
it off after the measurement has been made. The battery
current is sensed with the 0.005 resistor and amplified
26
TYPICAL
A
PPLICATI
Figure 14. This 0A to 2A Battery Current Monitor Draws Only 45 A from a 3V Battery
L
O
A
D
2A FULL
TO 4V
0.005
SCALE
2.7V
O
U
2k
S
–
+
SHDN
LTC1152
500pF
240k
100
1 F
by the LTC1152. The LTC1197L digitizes the amplifier
output and sends it to the microprocessor in serial
format. After each sample the LTC1197L automatically
powers down. The LT1004 provides the full-scale refer-
ence for the ADC. The circuit’s 45 A supply current is
dominated by the reference and the op amp. The circuit
can be located near the battery and data transmitted
serially to the microprocessor.
1
2
3
4
CS
+IN
– IN
GND
LTC1197L
1 F
D
V
CLK
V
OUT
REF
0.1 F
CC
+
8
7
6
5
56k
LT1004-1.2
TO P