ISL55190 Datasheet, PDF (15/18 Pages) Intersil Corporation – Single and Dual Ultra-Low Noise, Ultra-Low Distortion, Low Power Op Amp

ISL55190, ISL55290
CURRENT
INPUT
+5VDC
R_F
10kΩ
PARASITIC
L TO R
R_T
R_G-
100
R_SENSE
0.01Ω
R_G+
100Ω
V_REF
+2.5V
ISL55190
IN- V+
FEEDBACK
OUT
IN+ ^V-
R_REF
10kΩ
VOUT
R_L
CURRENT
INPUT
FIGURE 47. GROUND SIDE CURRENT SENSE AMPLIFIER
The ISL55190 single has a dedicated feedback pin which is
internally connected to the amplifier output and located next
to the inverting input pin. This additional output connection
enables the PC board trace capacitance at the inverting pin
to be minimized.
Current Sense Application Circuit
The schematic in Figure 47 provides an example of utilizing
the ISL55190 high speed performance with the ground
sensing input capability to implement a single-supply, G =1 0
differential low side current sense amplifier. This circuit can
be used to sense currents of either polarity. The reference
voltage applied to V_REF (+2.5V) defines the amplifier output
0A current sense reference voltage at one half the supply
voltage level (V_S = +5VDC), and R_SENSE sets the current
sense gain and full scale values. In this example the current
gain is 10A/V over a maximum current range of slightly less
than ±25A with R_SENSE = 0.01Ω. The amplifier V_IO error
(-1.1mV max) and input bias offset current (I_IO) error (1.3µA)
together contribute less than 15mV (150mA) at the output for
better than 0.3% full scale accuracy.
The amplifier’s high slew rate and fast pulse response make
this circuit suitable for low-side current sensing in PWM and
motor control applications. The excellent input overload
recovery response enables the circuit to maintain
performance in the presence of parasitic inductance that can
cause fast rise and falling edge spikes that can momentarily
overload the input stage of the amplifier.
15
FN6262.1
March 30, 2007