ZXCT1081
High voltage high-side current monitor
Description
The ZXCT1081 is a high side current sense
monitor with a gain of 10 and a voltage
output. Using this device eliminates the need
to disrupt the ground plane when sensing a
load current.
The wide input voltage range of 40V down to
as low as 3V make it suitable for a range of
applications; including systems operating
from industrial 24-28V rails and power
supplies.
The separate supply pin (V
CC
) allows the device
to continue functioning under short circuit
conditions, giving an end stop voltage at the
output.
For automotive applications the ZXCT1081 has
a 60V transient capability and ambient
temperature range of -40°C to 125°C.
Features
•
•
•
•
•
3V to 40V continuous high side voltage
Accurate high-side current sensing
Output voltage scaling x10
4.5V to 12V V
CC
range
Low quiescent current:
• 80µA supply pin
•
•
•
30µA I
SENSE+
SOT23-5 package
-40°C to 125°C ambient temperature range
Applications
•
•
•
•
•
•
Automotive current measurement
Industrial applications current measurement
Battery management
Over current monitor
Power management
Power adapters
Pin connections
V
CC
1
GND
2
OUT
3
4
SENSE+
5
SENSE-
Typical application circuit
V
IN
R
SENSE
4
SENSE+
5
SENSE-
V
CC
1
Vcc
ZXCT1081
OUT
3
GND
2
V
OUT
Ordering information
Device
ZXCT1081E5TA
Package
SOT23-5
Part mark
1081
1
Reel size
(inches)
7
Tape width
(mm)
8
Quantity per
reel
3000
www.zetex.com
Issue 3 - January 2007
© Zetex Semiconductors plc 2007
ZXCT1081
Absolute maximum ratings
Continuous voltage on SENSE+ and SENSE-
Transient voltage on SENSE+ and SENSE-
Voltage on all other pins
Differential sense voltage, V
SENSE
Operating temperature
Storage temperature
Maximum junction temperature
Package power dissipation
-0.6V and 45V
-0.6V and 65V
-0.6V and 14V
800mV
-40°C to 125°C
-55°C to 150°C
85°C
300mW at T
A
= 25°C (de-rate to zero at 125°C)
Operation above the absolute maximum rating may cause device failure. Operation at the absolute maximum ratings, for
extended periods, may reduce device reliability.
Recommended operating conditions
Parameter
V
IN
V
CC
V
SENSE
V
OUT
T
J
Common-mode sense+ input range
Supply voltage range
Differential sense input voltage range
Output voltage range
Ambient temperature range
Min.
3
4.5
0
0
-40
Max.
40
12
0.15
1.5
125
Units
V
V
V
V
°C
Pin function table
Pin
1
2
3
4
Name
V
CC
GND
OUT
SENSE+
Description
This is the analogue supply and provides power to internal circuitry
Ground pin
Output voltage pin. NMOS source follower with 20µA bias to ground
This is the positive input of the current monitor and has an input range from
60V down to 3V. The current through this pin varies with differential sense
voltage
This is the negative input of the current monitor and has an input range
from 60V down to 3V
5
SENSE-
Issue 3 - January 2007
© Zetex Semiconductors plc 2007
2
www.zetex.com
ZXCT1081
Electrical characteristics
Test conditions T
A
= 25°C, V
IN
= 12V, V
CC
= 5 V, V
SENSE(a)
= 100mV unless otherwise stated.
Symbol
I
CC
I
SENSE+
I
SENSE-
V
O(0)
V
O(10)
Gain
Parameter
V
CC
supply current
SENSE+ input current
SENSE- input current
Zero V
SENSE(a)
error
(b)
Output offset voltage
(c)
V
SENSE(a)
= 0V
V
SENSE(a)
= 10mV
V
SENSE(a)
= 10mV to 150mV
Conditions
V
CC
= 12V
Min.
40
15
10
0
-30
9.95
10
30
-3
V
OUT
= -30mV
V
OUT
= +30mV
V
CC
= 4.5V to 12V
V
IN
= 40V to 3V
V
SENSE(a) (AC)
= 10mV
PP
54
60
1
20
60
75
500
3
Typ.
80
30
40
Max.
120
60
80
35
+30
10.05
ppm/°C
%
mA
µA
dB
dB
kHz
Units
µA
µA
nA
mV
mV
V
OUT
/ V
SENSE(a)
V
OUT
TC
(d)
V
OUT
variation with
temperature
Acc
I
OH
I
OL
PSRR
Total output error
Output source current
Output sink current
V
CC
supply rejection
ratio
Common-mode sense
rejection ratio
-3dB small signal
bandwidth
CMRR
BW
NOTES:
(a) V
SENSE
= "V
SENSE+
" - "V
SENSE-
"
(b) The ZXCT1081 operates from a positive power rail and the internal voltage-current converter current flow is
unidirectional; these result in the output offset voltage for V
SENSE
= 0V always being positive.
(c) For V
SENSE
> 10mV, the internal voltage-current converter is fully linear. This enables a true offset to be defined and
used. V
O(10)
is expressed as the variance about an output voltage of 100mV>
(d) Temperature dependent measurements are extracted from characterization and simulation results.
Issue 3 - January 2007
© Zetex Semiconductors plc 2007
3
www.zetex.com
ZXCT1081
Typical characteristics
Test conditions unless otherwise stated: T
A
= 25°C, V
CC
= 5V, V
SENSE+
=12V, V
SENSE
= 100mV
Issue 3 - January 2007
© Zetex Semiconductors plc 2007
4
www.zetex.com
ZXCT1081
Typical characteristics
Test conditions unless otherwise stated: T
A
= 25°C, V
CC
= 5V, V
SENSE+
=12V, V
SENSE
= 100mV
Issue 3 - January 2007
© Zetex Semiconductors plc 2007
5
www.zetex.com
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