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 4µA, 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.
4µA quiescent current.
1% typical accuracy.
SOT23 -5 package.
APPLICATIONS
•
•
•
•
•
•
•
Battery Chargers
Smart Battery Packs
DC Motor control
Over current monitor
Power Management
Level translating
Programmable current source
APPLICATION CIRCUIT
V
in
R
sense
To Load
Vin
NC
ZXCT
Load
1010
GND
I out
V
out
R
out
ORDERING INFORMATION
PART NUMBER
ZXCT1010E
PACKAGE
SOT23-5
PARTMARKING
1010
ISSUE 1 - JUNE 2001
1
ZXCT1010
ABSOLUTE MAXIMUM RATINGS
Voltage on any pin
Continuous output current
Continuous sense voltage
Operating Temperature
Storage Temperature
Package Power Dissipation
SOT23-5
-0.6V to 20V (relative to GND)
25mA
V
in
+ 0.5V > V
sense†
> V
in
– 5V
-40 to 85°C
-55 to 125°C
(T
A
= 25°C)
500mW
ELECTRICAL CHARACTERISTICS
Test Conditions T
A
= 25°C, V
in
= 5V, R
out
= 100Ω.
SYMBOL
V
in
I
out 1
PARAMETER
V
CC
Range
Output current
CONDITIONS
Min
2.5
V
sense
=0V
V
sense
=10mV
V
sense
=100mV
V
sense
=200mV
V
sense
=1V
0
85
0.975
1.95
9.7
1
0
LIMITS
Typ
0.3
100
1.00
2.00
10.0
4
UNIT
Max
20
10
115
1.025
2.05
10.3
8
2500
100
V
µA
µA
mA
mA
mA
µA
mV
nA
I
q
V
sense 2
I
sense
Acc
Gm
BW
Ground pin current
Sense Voltage
Load pin
input current
Accuracy
Transconductance,
I
out
/ V
sense
Bandwidth
V
sense
=0V
R
sense
= 0.1Ω
V
sense
=200mV
-2.5
10000
RF P
in
= -20dBm
3
V
sense
= 10mV dc
V
sense
= 100mV dc
2.5
%
µA/V
300
2
kHz
MHz
Includes input offset voltage contribution
V
sense
=V
in
-V
load
3
-20dBm=63mVp-p into 50Ω
2
1
ISSUE 1 - JUNE 2001
2
ZXCT1010
TYPICAL CHARACTERISTICS
ISSUE 1 - JUNE 2001
3
ZXCT1010
PIN DESCRIPTION
Pin Name
V
in
Load
I
out
GND
Pin Function
Supply Voltage
Connection to load/battery
Output current, proportional to V
in
-V
load
Ground
CONNECTION DIAGRAM
SOT23-5
Package Suffix – E5
NC
GND
I
out
1
2
3
5
Load
4
V
IN
Top View
SCHEMATIC DIAGRAM
V
in
100Ω
+
-
Load
I
out
ISSUE 1 - JUNE 2001
4
ZXCT1010
POWER DISSIPATION
The maximum allowable power dissipation of the
device for normal operation (Pmax), is a function of
the package junction to ambient thermal resistance
(θja), maximum junction temperature (Tjmax), and
ambient temperature (Tamb), according to the
expression:
P
max
= (Tj
max
– T
amb
) /
θ
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
out1
E.g.
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 ohms.
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
Ω
TYPICAL CIRCUIT APPLICATION
Vin
NC
ZXCT
Load
1010
GND
I out
V
out
R
out
R
load
Where R
load
represents any load including DC motors,
a charging battery or further circuitry that requires
monitoring, R
sense
can be selected on specific
requirements of accuracy, size and power rating.
ISSUE 1 - JUNE 2001
5
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