Zxct1051 – Diodes ZXCT1051 User Manual
Page 8
ZXCT1051
© Zetex Semiconductors plc 2006
The ZXCT1051 has been designed to allow it to operate from supplies (V
CC
) ranging from 2.7V to
20V while sensing common mode signals from 0V up to V
CC
-2V.
When choosing appropriate values for R
SENSE
a compromise must be reached between in-line
signal loss (including potential power dissipation effects) and small signal accuracy.
Higher values for R
SENSE
gives better accuracy at low load currents by reducing the inaccuracies
due to internal offsets. For best operation the ZXCT1051 has been designed to operate with
V
SENSE
of the order of 50mV to 150mV.
Due to the very nature of current monitors they tend to saturate at very low sense voltages. This
is due to them being operated from single supply and that the basic configuration is that of a
unipolar voltage to current to voltage converter. The internal amplifiers at the heart of the current
monitor may well have a bipolar offset voltage but the output cannot go negative.
For this reason the ZXCT1051 has been designed to operate in a linear manner over a V
SENSE
range of 10mV to 150mV range, however it will still be monotonic down to V
SENSE
of 0V.
The device has a fixed DC voltage gain of 10; no external scaling resistors are required for the
output. Output voltage is simply defined as:
V
OUT
= gain x V
SENSE
(V)