ZXCT1010
Enhanced high-side current monitor
Description
The ZXCT1010 is a high side current sense
monitor. Using this device eliminates the
need to disrupt the ground plane when
sensing a load current.
It is an enhanced version of the ZXCT1009
offering reduced typical output offset and
improved accuracy at low sense voltage.
The wide input voltage range of 20V down to as
low as 2.5V make it suitable for a range of
applications. A minimum operating current of
just 4 A, combined with its SOT23-5 package
make suitable for portable battery equipment.
Features
•
•
•
•
•
•
•
•
Low cost, accurate high-side current
sensing
Output voltage scaling
Up to 2.5V sense voltage
2.5V – 20V supply range
300nA typical offset current
3.5 A quiescent current
1% typical accuracy
SOT23-5 package
Applications
•
•
•
•
•
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Battery chargers
Smart battery packs
DC motor control
Over current monitor
Power management
Programmable current source
Pinout information
NC
1
GND
2
I
OUT
3
4
V
IN
5
Load
Typical application circuit
Pinout - top view
Ordering information
Device
ZXCT1010E5TA
Issue 9 - July 2006
© Zetex Semiconductors plc 2006
Package
SOT23-5
Device
marking
101
1
Reel size
(inches)
7
Tape width
(mm)
8
Quantity
per reel
3000
www.zetex.com
ZXCT1010
Pin information
Pin
1
2
3
4
5
Name
N/C
GND
I
OUT
Description
Not connection
Ground connection
Output current, proportional to V
IN
- V
LOAD
V
SENSE+
Supply voltage
V
SENSE-
Connection to load/battery
Absolute maximum ratings
Voltage on any pin (relative to GND pin)
Continuous output current
Continous sense voltage
Ambient operating temperature range
Storage temperature
Package power dissipation
SOT23-5
-0.6 to 20V (relative to GND)
25mA
V
IN
+ 0.5V > V
SENSE
> V
IN
- 5V
-40 to 85°C
-55 to 150°C
T
amb
= 25°C
300mW
Operation above the absolute maximum rating may cause device failure. Operation at the
absolute maximum ratings, for extended periods, may reduce device reliability.
Issue 9 - July 2006
© Zetex Semiconductors plc 2006
2
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ZXCT1010
Electrical characteristics
Test conditions T
amb
= 25°C, V
IN
= 5V, R
OUT
= 100
Symbol
V
IN
I
OUT(a)
Parameter
V
CC
range
Output current
V
SENSE
= 0V
V
SENSE
= 10mV
V
SENSE
= 100mV
V
SENSE
= 200mV
V
SENSE
= 1V
I
Q
I
SENSE-
Acc
Gm
BW
Ground pin current V
SENSE
= 0V
0
V
SENSE-
input
current
Accuracy
Transconductance,
I
OUT
/V
SENSE
Bandwidth
RF P
IN
= -20dBm
(c)
V
SENSE
= 10mV DC
V
SENSE
= 100mV DC
NOTES:
(a) Includes input offset voltage contribution
(b) V
SENSE
= V
IN
-V
LOAD
(c) -20dBm = 63mVp-p into 50
Conditions
Min.
2.5
0
85
0.975
1.95
9.7
Limits
Typ.
0.3
100
1.00
2.00
10.0
3.5
Unit
Max.
20
10
115
2.05
10.3
8
2500
100
V
A
A
mA
mA
A
mV
nA
1.025 mA
V
SENSE(b)
Sense voltage
R
SENSE
= 0.1
V
SENSE
= 200mV
-2.5
10000
2.5
%
A/V
300
2
kHz
MHz
Issue 9 - July 2006
© Zetex Semiconductors plc 2006
3
www.zetex.com
ZXCT1010
Typical characteristics
Issue 9 - July 2006
© Zetex Semiconductors plc 2006
4
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ZXCT1010
Power dissipation
The maximum allowable power dissipation of the device
for normal operation (P
max
), is a function of the package
junction to ambient thermal resistance (
ja
), maximum
junction temperature (Tj
max
), and ambient temperature
(T
amb
), according to the expression:
Pmax = (Tj
max
– T
amb
) /
ja
The device power dissipation, P
D
is given by the
expression:
P
D
=I
OUT
.(V
IN
-V
OUT
) Watts
Applications information
The following lines describe how to scale a load current to an output voltage.
V
SENSE
= V
IN
- V
LOAD
V
OUT
= 0.01 x V
SENSE
x R
OUT(1)
For example:
A 1A current is to be represented by a 100mV output voltage:
1 Choose the value of R
SENSE
to give 50mV > V
SENSE
> 500mV at full load.
For example V
SENSE
= 100mV at 1.0A. R
SENSE
= 0.1/1.0 => 0.1 .
2 Choose R
OUT
to give V
OUT
= 100mV, when V
SENSE
= 100mV.
Rearranging
(1)
for R
OUT
gives:
R
OUT
= V
OUT
/(V
SENSE
x 0.01)
R
OUT
= 0.1 / (0.1 x 0.01) = 100
Schematic diagram
SENSE+
SENSE-
100
+
-
GND
OUT
Issue 9 - July 2006
© Zetex Semiconductors plc 2006
5
www.zetex.com
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