ZXCT1050
Precision wide input range current monitor
Description
The ZXCT1050 is a wide input range current
monitor, which operates over a range of input
voltages from ground up to V
CC
-2V. As a
result the ZXCT1050 can be used on the high
or low side of the load.
The ZXCT1050 provides variable gain by
using two external resistors. The first of
which sets the transconductance and the
second setting the overall gain.
The very low offset voltage enables a typical
accuracy of 1% for sense voltages of only 30mV,
giving better tolerances for small sense
resistors necessary at higher currents.
Features
•
•
•
•
•
•
Accurate down to end current sensing
Output voltage scaling x10
0 to V
CC
-2V sense input range
2.7 to 20V supply range
50µA quiescent current
SOT23-5 package
Applications
•
•
•
•
•
•
Power supply
DC motor and solenoid control
Battery management
Over current monitor
Power management
Short circuit detection
Pin connections
V
CC
1
GND
2
5
Typical application circuit
SENSE-
IN
R
SENSE
R
SHUNT
SENSE+
SENSE-
OUT
3
4
SENSE+
V
CC
ZXCT1050
Load
OUT
OUT
R
GAIN
Ordering information
Order code
ZXCT1050E5TA
Pack
SOT23-5
Part mark
1050
Reel size
(inches)
7
Tape width
(mm)
8
Quantity
per reel
3000
Issue 1 - June 2007
© Zetex Semiconductors plc 2007
1
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ZXCT1050
Absolute maximum ratings
V
CC
max.
Voltage on SENSE- and SENSE+
Voltage on all other pins
V
SENSE
= ‘(V
SENSE
+) - (V
SENSE
-)’
Operating temperature
Storage temperature
Maximum junction temperature
Package power dissipation
20V
-0.6 to V
CC
-0.6V and V
CC
+0.6V
500mV
-40 to 125°C
-55 to 150°C
150°C
300mW
*
at T
A
= 25°C (De-rate to zero for T
J
= 150°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
V
SENSE+
V
CC
V
SENSE
V
OUT
T
A
Parameter
Common-mode sense input range
Supply voltage range
Differential sense input voltage range
Output voltage range
Ambient temperature range
Min.
0
2.7
10
0
-40
Max.
V
CC
-2
20
300
V
CC
-2
125
Units
V
V
mV
V
°C
Recommended resistor gain setting combinations
Gain
10
20
50
100
20
50
100
R
SH
7.5k
7.5k
7.5k
7.5k
3.75k
1.5k
750
R
G
3.75k
7.5k
18.7k
37.5k
3.75k
3.75k
3.75k
Pin function table
PIN
1
2
3
4
5
Name
V
CC
GND
OUT
SENSE+
SENSE-
Description
This is the analog supply and provides power to internal circuitry.
Ground pin.
Output pin. A resistor, R
GAIN
, connected from this pin pin down to ground
develops an output voltage.
This is the positive input of the current monitor and has an input range from
0V up to V
CC
– 2V.
This is the negative input of the current monitor and has an input range from
0V up to V
CC
– 2V. The current through this pin varies with differential sense
voltage. A resistor, R
SHUNT
, from this pin to the rail being sensed set the
transconductance of the current monitor.
2
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Issue 1 - June 2007
© Zetex Semiconductors plc 2007
ZXCT1050
Electrical characteristics
Test conditions T
A
= 25°C, V
SENSE+
= 10V, V
CC
= 12V, V
SENSE
= 100mV, R
SH
= 7.5k , R
G
= 3.75k .
Symbol
I
Q
V
OUT
Parameter
V
CC
pin current
Output voltage
Conditions
V
SENSE
= 0V
V
SENSE
= 0V
=30mV
=100mV
=150mV
0
285
0.97
1.45
Min.
Typ.
45
3
300
1.00
1.50
60
15
Max.
70
15
315
1.03
1.55
150
150
300
10
-3
V
SENSE(DC)
= 10mV
V
SENSE(DC)
= 100mV
PSRR
CMRR
Power supply
rejection ratio
Common mode
rejection ratio
V
SENSE(AC)
= 10mV
PP
CL = 5pF,
300
0.8
60
70
3
%
kHz
MHz
dB
dB
Units
µA
mV
mV
V
V
nA
nA
ppm/°C
I
SENSE+
I
SENSE-
V
OUT
TC
Gain
Accuracy
BW
V
SENSE+
input current V
SENSE
= 0V
V
SENSE-
input current V
SENSE
= 0V
V
OUT
variation with
temperature
V
OUT
/V
SENSE
Total output error
Bandwidth
See note
(*)
V
CC
= 2.7V to 20V
V
SENSE+
= 0.7V
V
CC
= 20V
V
SENSE+
= 0 to 18V
NOTES:
(*) Temperature dependent measurements are extracted from characterisation and simulation results.
Issue 1 - June 2007
© Zetex Semiconductors plc 2007
3
www.zetex.com
ZXCT1050
Typical characteristics
R
G
= 3.75k , R
SH
= 7.5k
unless otherwise stated.
I
CC
Supply Current (A)
I
CC
Supply Current (A)
Supply Current v Supply Voltage
Supply Current v Input Voltage
I
CC
Supply Current (A)
I
S-
Sense Current (A)
Supply Current v Sense Voltage
Sense- Current v Supply Voltage
Percentage Change I
S-
(%)
Sense- Current v Temperature
I
S-
Sense Current (A)
Sense- Current v Sense Voltage
Issue 1 - June 2007
© Zetex Semiconductors plc 2007
4
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ZXCT1050
Typical characteristics
R
G
= 3.75k , R
SH
= 7.5k
unless otherwise stated.
10
V
OUT
- Output Voltage (V)
Δ
V
OUT
Output Voltage (mV)
1
5
100m
0
10m
1E-3
0.01
0.1
-5
-40 -20
0
20
40
60
80 100 120
Temperature Characteristic
V
OUT
- Output Voltage (mV)
1100
10.1
1050
1000
Incremental Gain
-15
-10
-5
0
5
10
15
20
10.0
950
900
-20
9.9
μ
0
50m
100m
150m
V
OUT
v Load Current
Δ
V
OUT
- Output Voltage (mV)
Δ
V
OUT
- Output Voltage (mV)
18
16
14
12
10
8
6
4
2
0
-2
-4
-6
-8
12
8
4
0
-4
-8
-12
Incremental Gain v Sense Voltage
0
2
4
6
8
10 12
14 16
18 20
0
5
10
15
20
Common Mode Characteristic
Supply Characteristic
Issue 1 - June 2007
© Zetex Semiconductors plc 2007
5
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