TS1100 TOUCHSTONE [Touchstone Semiconductor Inc], TS1100 Datasheet - Page 10

• Manufacturer Part Number: TS1100
• Description: A 1uA, +2V to +25V SOT23 Precision Current-Sense Amplifier
• Manufacturer: TOUCHSTONE [Touchstone Semiconductor Inc]

TS1100
low-pass filters in series with the current-sense
amplifier’s inputs only introduces additional offset
voltage and gain errors. To minimize or eliminate
altogether the need for external low-pass filters and
to maintain low input offset voltage and gain errors,
the TS1100 incorporates a 50-kHz (typ), 2
differential low-pass filter as shown in the TS1100’s
Block Diagram.
Optional Output Filter Capacitor
If the TS1100 is part of a signal acquisition system
where its OUT terminal is connected to the input of
an ADC with an internal, switched-capacitor track-
and-hold
sampling capacitor can cause voltage droop at V
A 22nF to 100nF good-quality ceramic capacitor
from the OUT terminal to GND forms a low-pass
filters with the TS1100’s R
minimize voltage droop (holding V
during the sample interval. Using a capacitor on the
OUT terminal will also reduce the TS1100’s small-
signal bandwidth as well as band-limiting amplifier
noise.
PC Board Layout and Power-Supply Bypassing
For optimal circuit performance, the TS1100 should
be in very close proximity to the external current-
sense resistor and the pcb tracks from RSENSE to
Page 10
Figure 2: Using Two TS1100s for Bidirectional Load Current Detection
circuit,
the
internal
OUT
and should be used to
track-and-hold’s
OUT
constant
nd
-order
OUT
.
the RS+ and the RS- input terminals of the TS1100
should be short and symmetric. Also recommended
are a ground plane and surface mount resistors and
capacitors.
Using the TS1100 in Bidirectional Load Current
Applications
In many battery-powered systems, it is oftentimes
necessary to monitor a battery’s discharge and
charge currents. To perform this function, a
bidirectional current-sense amplifier is required. The
circuit illustrated in Figure 2 shows how two
TS1100s can be configured as a bidirectional
current-sense amplifier. As shown in the figure, the
RS+/RS- input pair of TS1100 #2 is wired opposite
in polarity with respect to the RS+/RS- connections
of TS1100 #1. Current-sense amplifier #1 therefore
measures the discharge current and current-sense
amplifier #2 measures the charge current. Note that
both output voltages are measured with respect to
GND. When the discharge current is being
measured, V
case where charge current is being measured, V
is zero, and V
OUT1
OUT2
is active and V
is active.
OUT2
is zero; for the
TS1100DS r1p0
RTFDS
OUT1