zxct1020 Zetex Semiconductors plc., zxct1020 Datasheet - Page 11

• Manufacturer Part Number: zxct1020
• Description: Zxct1020 - Precision Current Output Monitor
• Manufacturer: Zetex Semiconductors plc.

Application information
The ZXCT1020 has a V
voltage applied to the ZXCT1020 must be applied to this pin. The S+ and S- pins are used to
measure the current flowing to the load through the sense resistor. In normal use, the S+ is tied
to V
The ZXCT1020 has a programmable gain set by the ratio of two external resistors R
R
as:
The ZXCT1020 has been tested to the same conditions as the ZXCT1021 giving an overall voltage
gain of 10. The gain of the ZXCT1020 can be adjusted simply by varying R
of 50 R
Decreasing R
reduce the overall output impedance.
To achieve a gain of 100, for example, the following resistor values could be used:
Issue 1 - August 2007
© Zetex Semiconductors plc 2007
SH
B
sets the transconductance whereas R
via a shunt resistor, R
Where V
R
V
G
SH
OUT
is increased from 15k
= 150 R
SH
=
SENSE
increases the transconductance and, if for any given gain, reducing the R
--------- -
R
R
G
SH
G
= 15k
= R
R
V
×
B
R
OUT
SH
V
SENSE
pin that is used to provide power to the current monitor. The maximum
G
SENSE
H
making the ZXCT1020 essentially line powered.
S+
x I
to 75k . An alternative is to decrease R
L
1
3
G
V
set the gain and results in an output voltage defined
B
4
2
11
ZXCT1020
GND
+
R
-
S
(LOAD)
S-
5
I
L
SH
G
from 1.5k
. So to achieve a gain
ZXCT1020
www.zetex.com
G
and R
to 300 .
SH
SH
will
.