Diodes ZXCT1020 - Manual

ZXCT1020
Issue 1 - August 2007 1 www.zetex.com
© Zetex Semiconductors plc 2007
ZXCT1020
Low offset current output current monitor
Description
Ordering information
The ZXCT1020 is a precision high-side current
sense monitor. Using this type of device
eliminates the need to disrupt the ground
plane when sensing a load current.
The ZXCT1020 uses two external resistors to
set the overall voltage gain for applications
where improved accuracy at small sense
voltages is required. For fixed gain variants
Zetex offers the ZXCT1021 (G=10) and
ZXCT1022 (G=100).
The ZXCT1020 footprint follows that of the
ZXCT1021/2 with only 2 additional resistors
required:
One resistor between pins 1 and 4 for setting
transconductance, and the other between
pins 3 and 2 for setting overall gain.
Current output enables the user to set the gain
via these external resistors. Using two external
resistors to set the gain ensures optimal
versatility as the transconductance can be varied
to meet the output impedance requirements of
the load that the ZXCT1020 has to drive.
The very low offset voltage enables a typical
accuracy of 3% for sense voltages of only 10mV,
giving better tolerances for small sense
resistors necessary at higher currents.
The wide input voltage range of 20V down to as
low as 2.5V make it suitable for a range of
applications. With a minimum operating current
of just 25µA, combined with its SOT23-5
package make it suitable for portable battery
equipment too.
Features
• Accurate high-side current sensing
• Versatile current output scaling
• 2.5V - 20V operating range
• 25µA quiescent current
• 1% typical accuracy
• SOT23-5 package
Applications
• Battery chargers
• Over-current monitor
• Motherboard power supply current measurement
• Level translating
• Programmable current source
Pinout information Typical application circuit
Order reference Package Device
marking
Status Reel size
(inches)
Quantity
per reel
Tape width
(mm)
ZXCT1020E5TA SOT23-5 1020 Preview 7 3000 8
S+
GND
OUT
S-
V
B
Top view
1
2
3
5
4
S+
S-
(LOAD)
V
B
I
L
R
SH
R
S
GND
V
OUT
5
4
-
+
1
ZXCT1020
2
3
R
G