DC1536A Analog Devices

DEMO CIRCUIT DC1536 LTC6102-1 QUICK START GUIDE LTC6102-1 Precision Zero Drift Current Sense Amplifier DESCRIPTION Demonstration circuit 1536 is a General Purpose High- ing such as A/D conversion). Remote positioning of Rout Side Current-Sense Amplifier featuring the LTC6102-1. can be evaluated by simply removing the on board Rout resistor (R3). This demo board amplifies an on-board current-sense resistor voltage-drop, providing a precision uni-polar The key performance characteristics of the LTC6102-1 output voltage proportional to load current through the and DC1536 are shown in the Performance Summary sense resistor. below. The LTC6102-1 is the same as the LTC6102 but has an Enable feature at pin 3. On the Demo Board this The demo circuit includes scaling resistors that program pin is pulled up by a 1M resistor so the default setting the gain of the circuit to 33.3V/V. The LTC6102-1 is is the LTC6102-1 is Enabled. powered from the same supply that the sense resistor is connected to and provides a ground referenced output. The LTC6102-1 can perform current measurements on Design files for this circuit board are available. Call supplies ranging from 4V to 60V. Since the output volt- the LTC factory. age is a function of a controlled current through Rout, L, LT are registered trademarks of Linear Technology Corporation. Other product names ground-loop errors can be eliminated by simply locating may be trademarks of the companies that manufacture the products. Rout at the destination point (subsequent signal process- PERFORMANCE SUMMARY Specifications are at T = 25C A SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS V Monitored Supply Input Range 4 548 60 V IN V Measurement Output Signal I = 10A 2.0 V MON OUT I Measurement Output Signal (current mode) I =10A, R3 removed 400 A MON OUT I Output Load Current Range Thermal limit of R 12 A OUT SENSE I V Quiescent Current V =12V, I = 0A 230 A INQ IN IN OUT t V step-response time I step from 0A to 10A 4 s R MON OUT OPERATING PRINCIPLES The LTC6102-1 operates by amplifying the voltage drop the input resistor and is essentially as accurate as the across a sense resistor placed in series with the power resistors used. In DC1536 as shipped, the sense resistor source of the load to be monitored. The sense inputs of installed is 6m and the resistor ratio sets the gain to the amplifier differentially measure the sense-resistor 33.3V/V, so the nominal output scaling is 200mV per drop to control an internal variable current source that Ampere of load current. Other scaling can be produced allows translation of the input information to a level ref- by resistor replacement on the demo circuit. erenced to V (ground in this demo circuit). The circuit The DC1536 Schematic diagram is shown in Figure 2. gain is established by the ratio of the output resistor to 1 LTC6102-1 QUICK START PROCEDURE Demonstration circuit 1536 is easy to set up to evaluate 2. Connect a voltmeter or oscilloscope probe to the MON the performance of the LTC6102-1. Refer to Figure 1 for terminal, with the common connection or ground clip proper measurement equipment setup and follow the tied to GND. procedure below: 3. Connect a load to the OUT terminal (positive) and re- 1. With power off, connect the power supply positive to turn (negative) to the common of the power supply. IN and the common to GND. This supply should be in The load may be a power resistor, active load instru- the range of 4V to 60V. If this supply is not equipped ment, or other circuit of interest. with an accurate current readout, a DMM (set to 4. Turn on the power supply. measure Amperes) may be connected in series with 5. Measure an output voltage that corresponds to the the supply as shown in Figure 1. load current. V = 0.2I for the factory installed MON OUT NOTE. Be sure that the current capacity of the DMM is adequate to resistors. handle the intended load current. The Load Resistor must have the appropriate power rating. 1.0 0.2 POWER 10. SUPPLY DMM DMM + COM A COM V A COM V LOAD (10) Figure 1. Proper Measurement Equipment Setup 2