ZXCT1009
HIGH-SIDE CURRENT MONITOR
DESCRIPTION
The ZXCT1009 is a high side current sense monitor.
Using this device eliminates the need to disrupt the
ground plane when sensing a load current.
It takes a high side voltage developed across a current
shunt resistor and translates it into a proportional
output current.
A user defined output resistor scales the output
current into a ground-referenced 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 package make it a unique solution for
portable battery equipment.
FEATURES
APPLICATIONS
•
Battery Chargers
•
Smart Battery Packs
•
DC Motor control
•
Over current monitor
•
Power Management
•
Level translating
•
Programmable current source
APPLICATION CIRCUIT
•
Low cost, accurate high-side current sensing.
•
Output voltage scaling.
•
Up to 2.5V sense voltage.
•
2.5V – 20V supply range.
•
4µA quiescent current.
•
1% typical accuracy.
•
SOT23 & SM8
†
packages.
V
in
R
sense
To Load
ZXCT
1009
V
out
R
out
ORDERING INFORMATION
PART NUMBER
ZXCT1009F
ZXCT1009T8
PACKAGE
SOT23
SM8
PARTMARKING
109
ZXCT1009
† 8 leaded SOT223
ISSUE 4 - JULY 2003
1
SEMICONDUCTORS
ZXCT1009
ABSOLUTE MAXIMUM RATINGS
Voltage on any pin
Continuous output current
Continuous sense voltage
Operating Temperature
Storage Temperature
Package Power Dissipation
SOT23
SM8
-0.6V to 20V (relative to I
out
)
25mA
V
in
+ 0.5V > V
sense
†
> V
in
– 5V
-40 to 85°C
-55 to 125°C
(T
A
= 25°C)
450mW
2W
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
1
90
0.975
1.95
9.6
0
LIMITS
Typ
4
104
1.002
2.0
9.98
UNIT
Max
20
15
120
1.025
2.05
10.2
2500
100
V
µA
µA
mA
mA
mA
mV
nA
V sense
I sense
Acc
Gm
BW
†
Sense Voltage
Load pin
input current
Accuracy
Transconductance,
I out / V sense
Bandwidth
RF P in = -20dBm‡
V sense = 10mV dc
V sense = 100mV dc
R sense = 0.1Ω
V sense =200mV
-2.5
10000
2.5
%
µA/V
300
2
kHz
MHz
1
†
Includes input offset voltage contribution
V
sense
=V
in
-V
load
‡ -20dBm=63mVp-p into 50Ω
ISSUE 4 - JULY 2003
SEMICONDUCTORS
2
ZXCT1009
TYPICAL CHARACTERISTICS
5
10m
I
OUT
- Output Current (A)
Output Current Error (%)
1m
V
IN
= 5V
Tamb = 25°C
R
OUT
= 0
W
4
3
2
1
0
-1
-2
10m
100m
Typical
V
IN
= 5V
Tamb = 25°C
R
OUT
= 0
W
100µ
10µ
100µ
1m
10m
100m
1
1
V
SENSE
(V)
V
SENSE
(V)
Typical Output v Sense Voltage
3
10.2
V
IN
= 5V
V
SENSE
= 1V
R
OUT
= 0
W
Error v Sense Voltage
I
OUT
- Output Current (mA)
V
IN
= 5V, Tamb = 25°C, RF P
IN
= -20dBm
0
-3
DC V
SENSE
= 0.01V
10.0
9.8
Gain (dB)
-6
-9
-12
0.01
DC V
SENSE
= 0.1V
DC V
SENSE
= 1V
9.6
9.4
-40
-20
0
20
40
60
80
0.1
1
10
Temperature (°C)
Frequency (MHz)
Output Current v Temperature
12
0
V
IN
= 5V
Tamb = 25°C
R
OUT
= 0
W
V
SENSE
= 1V
V
SENSE
= 0.8V
V
SENSE
= 0.6V
V
SENSE
= 0.4V
V
SENSE
= 0.2V
Frequency Response
I
OUT
- Output Current (mA)
-10
-20
10
8
6
4
2
0
0
V
IN
= 5V
Tamb = 25°C
RF P
IN
= -20dBm
V
SENSE
= 1V
Rejection (dB)
-30
-40
-50
-60
-70
-80
-90
V
SENSE
= 0.1V
V
SENSE
= 0.01V
1
2
3
4
5
1
10
100
1k
10k
100k
1M
10M
V
IN
- Supply Voltage (V)
Frequency (Hz)
Transfer Characteristic
ISSUE 4 - JULY 2003
3
Common Mode Rejection
SEMICONDUCTORS
ZXCT1009
TYPICAL CHARACTERISTICS (Cont.)
SCHEMATIC DIAGRAM
V
in
100Ω
+
-
Load
I
out
PIN DESCRIPTION
Pin Name
V in
Load
I out
Pin Function
Supply Voltage
Connection to load/battery
Output current, proportional to V in -V load
CONNECTION DIAGRAMS
SOT23
Package Suffix – F
SM8
Package Suffix – T8
Load
N/C
1
1
2
3
4
8
7
6
5
Load
3
N/C
N/C
N/C
N/C
I
out
V
in
Iout
V
in
2
Top View
Top View
ISSUE 4 - JULY 2003
SEMICONDUCTORS
4
ZXCT1009
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
E.g.
The device power dissipation, P
D
is given by the
expression:
P
D
=I
out
.(V
in
-V
out
) Watts
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)
SM8
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
A 1A current is to be represented by a 100mV output
voltage:
R
out
= 0.1 / (0.1 x 0.01) = 100
Ω
SOT23
TYPICAL CIRCUIT APPLICATION
V
in
R
sense
ZXCT1009
Vin
Load
Iout
R
load
V
out
R
out
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 4 - JULY 2003
5
SEMICONDUCTORS
京公网安备 11010802033920号
EEWORLD
