LTC2945_15 Datasheet, PDF (1/34 Pages) Linear Technology – Wide Range I2C Power Monitor

LTC2945
Wide Range
I²C Power Monitor
Features
n _{Rail-to-Rail Input Range: 0V to 80V}
n _{Wide Input Supply Range: 2.7V to 80V}
n _{Shunt Regulator for Supplies >80V}
n _{Δ∑ ADC with less than ±0.75% Total Unadjusted Error}
n _{12-Bit Resolution for Current and Voltages}
n _{Internal Multiplier Calculates 24-Bit Power Value}
n _{Stores Minimum and Maximum Values}
n _{Alerts When Limits Exceeded}
n _{Additional ADC Input Monitors an External Voltage}
n _{Continuous Scan and Snapshot Modes}
n _{Shutdown Mode with IQ < 80µA}
n _{Split SDA for Opto-Isolation}
n _{Available in 12-Lead 3mm × 3mm QFN and MSOP}
Packages
Applications
n _{Telecom Infrastructure}
n _Industrial
n _Automotive
n _Consumer
Description
The LTC^®2945 is a rail-to-rail system monitor that mea-
sures current, voltage, and power. It features an operating
range of 2.7V to 80V and includes a shunt regulator for
supplies above 80V to allow flexibility in the selection of
input supply. The current measurement range of 0V to
80V is independent of the input supply. An onboard 0.75%
accurate 12-bit ADC measures load current, input voltage
and an auxiliary external voltage. A 24-bit power value is
generated by digitally multiplying the measured 12-bit load
current and input voltage data. Minimum and maximum
values are stored and an overrange alert with program-
mable thresholds minimizes the need for software polling.
Data is reported via a standard I²C interface. Shutdown
mode reduces power consumption to 20µA.
The LTC2945 I²C interface includes separate data input
and output pins for use with standard or opto-isolated I²C
connections. The LTC2945-1 has an inverted data output
for use with inverting opto-isolator configurations.
L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear
Technology Corporation. All other trademarks are the property of their respective owners.
Typical Application
Wide Range Power Monitor with Onboard ADC and I²C
V_IN
4V TO 80V
0.02Ω
TO
LOAD
ADC Differential
Nonlinearity (ADIN)
0.3
0.1µF
NINE I²C
ADDRESSES
SENSE⁺ SENSE^–
V_DD
ALERT
LTC2945
INTV_CC
SCL
ADR1
SDAI
ADR0
GND
SDAO
ADIN
2945 TA01
I²C
INTERFACE
MEASURED
VOLTAGE
0.2
0.1
0.0
–0.1
–0.2
–0.3
0
1024
2048
CODE
3072
4096
2945 TA01a
ADC Integral Nonlinearity
(ADIN)
0.3
0.2
0.1
0.0
–0.1
–0.2
–0.3
0
1024
2048
CODE
3072
4096
2945 TA01b
For more information www.linear.com/LTC2945
2945fa
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