Datasheet
Power-Up Conditions BASIC ADC FUNCTIONS
Critical
DAC+
Critical
DAC -
´
CMP
CMP
Filter
Watchdog
PowerRegister
CurrentRegister
I C
2
Interface
VoltageRegister
Convert
ADC
GND GPIO
Supply
Voltage
Current
Shunt
V =V V-
SHUNT IN+ IN-
Typically<50mV
V =V GND-
BUS IN-
Rangeof0Vto26V
TypicalApplication12V
Supply Load
INA209PowerSupply
3Vto5.5V
Critical
Overlimit
Warning
Alert
Data
CLK
INA209
V
IN+
V
IN-
V
S
INA209
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......................................................................................................................................................... SBOS403B – JUNE 2007 – REVISED MARCH 2009
Power-up conditions apply to a software reset via the The two analog inputs to the INA209, V
IN+
and V
IN –
,
RST bit (bit 15) in the Configuration Register, or the connect to a shunt resistor in the bus of interest. The
I
2
C bus General Call Reset. At device power up, all INA209 is typically powered by a separate supply
Status bits are masked. Warning, Over-Limit, Critical, from +3V to +5.5V. The bus being sensed can vary
and SMBus Alert functions are disabled. All watchdog from 0V to 26V. There are no special considerations
outputs default to active low and transparent for power-supply sequencing (for example, a bus
(non-latched) modes. voltage can be present with the supply voltage off,
and vice-versa). The INA209 senses the small drop
across the shunt for shunt voltage, and senses the
voltage with respect to ground from V
IN –
for the bus
voltage. Figure 21 illustrates this operation.
Figure 21. INA209 Configured for Shunt and Bus Voltage Measurement
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