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dc1697af

DEMO MANUAL DC1697A

 DESCRIPTION

LTC2945 

Wide Range I

2

C Power Monitor 

Demonstration circuit 1697A features the LTC2945. The 
LTC2945 is a rail-to-rail system monitor that measures 
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 sup-
ply. The current common mode 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 

L

, LT, LTC, LTM, QuikEval, Linear Technology and the Linear logo are registered trademarks of 

Linear Technology Corporation. All other trademarks are the property of their respective owners.

 BOARD PHOTO

maximum values are stored and an overrange alert with 
programmable thresholds minimizes the need for software 
polling. Data is reported via a standard I

2

C interface. The 

demo board is populated for a 5A application. This can 
be changed by populating R1 accordingly. 

Design files for this circuit board are available at 
http://www.linear.com/demo

Figure 1. Proper Test Equipment Setup

4V TO 80V

TO DC590

LOAD

dc1697A F01

Summary of Contents for DC1697A

Page 1: ...xternal voltage A 24 bit power value is generated by digitally multiplying the measured 12 bit load current and input voltage data Minimum and L LT LTC LTM QuikEval Linear Technology and the Linear logo are registered trademarks of Linear Technology Corporation All other trademarks are the property of their respective owners BOARD PHOTO maximum values are stored and an overrange alert with program...

Page 2: ...for INTVCC when above 7V INTVCC Internal Low Voltage Supply Input Output This turret is used to power internal circuitry and can be con figuredasadirectinput asalinearregulatorfromahigher voltage connected to VDD or as a shunt regulator Please see LTC2945 data sheet for more details ADIN ADC input measured by the onboard ADC Can measure between 0V and 2 048V VPU Pull up voltage for the _ALERT LED ...

Page 3: ...At this point as long as 4V to 80V is provided at VIN the part will function correctly However shouldVDD_SELbetiedtoEXTVDDthenaseparatevoltage source should be provided at the EXTVDD turret Should VDD_SEL be tied to INTVCC then if VIN is less than 7V a 5V supply should be provided at the INTVCC turret This is illustrated in the following figures If the system is connected properly the INTVCC green...

Page 4: ... the supply being monitored The 5k shunt resistor shown provides 15mA to INTVCC at 80V The allowable range of resistance for a given input range is given by the following formula VS MAX 5 9V 35mA RSHNT VS MIN 6 7V 1mA ILOAD MAX 80V 5k dc1697A F03 Figure 3 Powering DC1697A Using High Side Shunt Regulator to Allow for Input Voltage Higher Than 80V Jumper VDD_SEL Set to INTVCC With A Resistor Connect...

Page 5: ...UAL DC1697A HARDWARE SETUP Figure 4 Powering DC1697A Through Low Side Shunt Regulator in High Side Current Sense Topology Jumper VDD_SEL Set to INTVCC with a Resistor Connected to INTVCC 0V TO 80V 80V 5k LOAD dc1697A F04 ...

Page 6: ...er VDD_SEL set to EXTVDD with the 48V input tied to VIN and GND and the 48V Return tied to EXTVDD The DC590 provides isolation and level shifting as the I2C interface is operating at 48V with respect to 48V RTN which is normally at earth ground potential 48V RETURN 48V INPUT 48V RETURN LOAD dc1697A F05 TO DC590 PROVIDES ISOLATION ...

Page 7: ... pin and LED on the board react With Alert Persist checked on an ALERT the corresponding FAULT button will light up red on the software GUI The ALERT LED should also be red on the DC1697A itself Click the Clear Alerts button to clear all alerts With Alert Persist not enabled an alert event will still light up the corresponding FAULT button however the ALERT LED on the board will turn on briefly be...

Page 8: ...TEC TMM 103 02 L D 10 1 JP2 Headers Single Row 3 Pins 2mm CTRS SAMTEC TMM 103 02 L S 11 2 JP3 JP4 Headers 4 Pins 2mm CTRS SAMTEC TMM 104 02 L S 12 1 J1 Header 2 mm CTRS MOLEX 878 31 1420 13 1 Q1 N Channel MOSFET SOT23 DIODES ZETEX 2N7002 7 F 14 1 R1 Res LRC 0 020 1 0W 1 2010 IRC LRF20 10LF 01 R020 F 15 1 R2 Res Chip 51 0 1W 5 0603 VISHAY CRCW060351R0JNEA 16 1 R3 Res Chip 10k 0 1W 5 0603 VISHAY CRC...

Page 9: ...POWER MONITOR N A LTC2945CUD KIM T MARK T SIZE DATE V E R O N C I SHEET OF TITLE APPROVALS PCB DES APP ENG TECHNOLOGY Fax 408 434 0507 Milpitas CA 95035 Phone 408 432 1900 1630 McCarthy Blvd LTC Confidential For Customer Use Only CUSTOMER NOTICE LINEAR TECHNOLOGY HAS MADE A BEST EFFORT TO DESIGN A CIRCUIT THAT MEETS CUSTOMER SUPPLIED SPECIFICATIONS HOWEVER IT REMAINS THE CUSTOMER S RESPONSIBILITY ...

Page 10: ...LUDING ANY WARRANTY OF MERCHANTABILITY OR FITNESS FOR ANY PARTICULAR PURPOSE EXCEPT TO THE EXTENT OF THIS INDEMNITY NEITHER PARTY SHALL BE LIABLE TO THE OTHER FOR ANY INDIRECT SPECIAL INCIDENTAL OR CONSEQUENTIAL DAMAGES The user assumes all responsibility and liability for proper and safe handling of the goods Further the user releases LTC from all claims arising from the handling or use of the go...

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