LTC2945
Wide Range
2
I C Power Monitor
FEATURES DESCRIPTION
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Rail-to-Rail Input Range: 0V to 80V The LTC 2945 is a rail-to-rail system monitor that mea-
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Wide Input Supply Range: 2.7V to 80V sures current, voltage, and power. It features an operating
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Shunt Regulator for Supplies >80V range of 2.7V to 80V and includes a shunt regulator for
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ADC with less than 0.75% Total Unadjusted Error supplies above 80V to allow flexibility in the selection of
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12-Bit Resolution for Current and Voltages input supply. The current measurement range of 0V to
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Internal Multiplier Calculates 24-Bit Power Value 80V is independent of the input supply. An onboard 0.75%
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Stores Minimum and Maximum Values accurate 12-bit ADC measures load current, input voltage
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Alerts When Limits Exceeded and an auxiliary external voltage. A 24-bit power value is
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Additional ADC Input Monitors an External Voltage generated by digitally multiplying the measured 12-bit load
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Continuous Scan and Snapshot Modes current and input voltage data. Minimum and maximum
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Shutdown Mode with I < 80A values are stored and an overrange alert with program-
Q
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Split SDA for Opto-Isolation mable thresholds minimizes the need for software polling.
2
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Available in 12-Lead 3mm 3mm QFN and MSOP Data is reported via a standard I C interface. Shutdown
Packages mode reduces power consumption to 20A.
2
The LTC2945 I C interface includes separate data input
APPLICATIONS
2
and output pins for use with standard or opto-isolated I C
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connections. The LTC2945-1 has an inverted data output
Telecom Infrastructure
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for use with inverting opto-isolator configurations.
Industrial
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Automotive
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.
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Consumer
TYPICAL APPLICATION
2
Wide Range Power Monitor with Onboard ADC and I C ADC Differential ADC Integral Nonlinearity
Nonlinearity (ADIN) (ADIN)
0.02
V TO
IN
4V TO 80V
LOAD 0.3 0.3
0.2 0.2
+
SENSE SENSE
V ALERT 0.1 0.1
DD
LTC2945
INTV
SCL
CC
2
I C
0.1F 0.0 0.0
INTERFACE
ADR1 SDAI
2
NINE I C
0.1 0.1
ADDRESSES
ADR0 SDAO
MEASURED
ADIN
VOLTAGE
0.2 0.2
GND
2945 TA01
0.3 0.3
0 1024 2048 3072 4096 0 1024 2048 3072 4096
CODE CODE
2945 TA01a 2945 TA01b
2945fb
1
For more information www.linear.com/LTC2945
ADC DNL (LSB)
ADC INL (LSB)LTC2945
ABSOLUTE MAXIMUM RATINGS
(Notes 1, 2)
SCL, SDAI Voltages (Note 4) ..................... 0.3V to 5.9V
V Voltage .............................................. 0.3V to 100V
DD SCL, SDAI Clamp Current ........................................5mA
+
SENSE Voltage ...........................................1V to 100V
Operating Temperature Range
+ +
SENSE Voltage .....1V or SENSE 1V to SENSE + 1V
LTC2945C ................................................ 0C to 70C
INTV Voltage (Note 3) ........................... 0.3V to 5.9V
CC LTC2945I .............................................40C to 85C
ADR1, ADR0, ADIN, ALERT, SDAO, SDAO
LTC2945H .......................................... 40C to 125C
Voltage ......................................................... 0.3V to 7V
Storage Temperature Range .................. 65C to 150C
INTV Clamp Current ...........................................35mA
CC Lead Temperature (Soldering, 10sec)
MS Package Only ..............................................300C
PIN CONFIGURATION
LTC2945
TOP VIEW
TOP VIEW
12 11 10
+
V 1 12 SENSE
DD
2
INTV 1 9 ALERT INTV 11 SENSE
CC CC
3
ADR1 10 ALERT
ADR1 2 13 8 SDAO
4 9 SDAO
ADR0
ADR0 3 7 SDAI
ADIN 5 8 SDAI
GND 6 7 SCL
4 5 6
MS PACKAGE
12-LEAD PLASTIC MSOP
T = 125C, q = 135C/W
JMAX JA
UD PACKAGE
3mm) PLASTIC QFN
12-LEAD (3mm
T = 125C, q = 58.7C/W
JMAX JA
EXPOSED PAD (Pin 13) PCB GND CONNECTION OPTIONAL
LTC2945-1
TOP VIEW
TOP VIEW
12 11 10
+
V 1 12 SENSE
DD
2
INTV 1 9 ALERT INTV 11 SENSE
CC CC
3
ADR1 10 ALERT
ADR1 2 13 8 SDAO
4 9 SDAO
ADR0
ADR0 3 7 SDAI
ADIN 5 8 SDAI
GND 6 7 SCL
4 5 6
MS PACKAGE
12-LEAD PLASTIC MSOP
T = 125C, q = 135C/W
JMAX JA
UD PACKAGE
3mm) PLASTIC QFN
12-LEAD (3mm
T = 125C, q = 58.7C/W
JMAX JA
EXPOSED PAD (Pin 13) PCB GND CONNECTION OPTIONAL
2945fb
2
For more information www.linear.com/LTC2945
ADIN V ADIN V
DD DD
+ +
GND SENSE GND SENSE
SCL SENSE
SCL SENSE