2.7.5 RSENSE Kelvin Connections

trates the connections between the current-sense amplifier and the current-sense resistor. The pcb layout should be balanced and

2.7.6 RSENSE Composition

Current-shunt resistors are available in metal film, metal strip, and wire-wound constructions. Wire-wound current-shunt resistors are

constructed with wire spirally wound onto a core. As a result, these types of current shunt resistors exhibit the largest self-inductance. In

applications where the load current contains high-frequency transients, metal film or metal strip current sense resistors are recommen-

ded.

2.7.7 Internal Noise Filter

In power management and motor control applications, current-sense amplifiers are required to measure load currents accurately in the

presence of both externally-generated differential and common-mode noise. An example of differential-mode noise that can appear at

the inputs of a current-sense amplifier is high-frequency ripple. High-frequency ripple (whether injected into the circuit inductively or ca-

generated, common-mode noise is the high-frequency output ripple of a switching regulator that can result in common-mode noise in-

jection into both inputs of a current-sense amplifier.

Even though the load current signal bandwidth is dc, the input stage of any current-sense amplifier can rectify unwanted, out-of-band

noise that can result in an apparent error voltage at its output. Against common-mode injection noise, the current-sense amplifier’s in-

ternal common-mode rejection ratio is 130 dB (typ).

To counter the effects of externally-injected noise, the TS1107/10 incorporates a 50 kHz (typ), 2nd-order differential low-pass filter as

shown in the TS1107/10’s block diagram, thereby eliminating the need for an external low-pass filter which can generate errors in the

offset voltage and the gain error.

2.7.8 PC Board Layout and Power-Supply Bypassing

For optimal circuit performance, the TS1107/10 should be in very close proximity to the external current-sense resistor and the pcb

surface mount resistors and capacitors, as well as a ground plane.

TS1107/10 Data Sheet

System Overview

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