ZXCT1023
MICROPOWER FIXED GAIN OF 50 CURRENT MONITOR
Description
The ZXCT1023 is a precision high-side current sense
monitor. Using this type of device eliminates the need to
disrupt the ground plane when sensing a load current.
The ZXCT1023 has a fixed internal gain of 50 and the only
external component required is the external current sense
resistor; this combined with its 1.2mm x 1.8mm TDFN
package more than quarters the solution size of the
ZXCT1010.
The wide input voltage range of 20V down to as low as
2.5V makes it suitable for a range of applications.
The combination of operation down to 2.5V and just 3.5µA
quiescent current makes it ideal for single cell
Li-Ion/polymer battery charge/discharge measurement
applications.
Pin Assignments
TDFN1218-4L
OUT 1
GND 2
Top View
4 S+
3 S-
Features
•
•
•
•
•
Accurate high-side current sensing
Fixed gain of 50 output scaling
2.5V – 20V operating range
3.5µA quiescent current
TDFN1218 package
Applications
•
•
•
Battery capacity measurement
Battery chargers
Over-current monitor
Typical Application Circuit
S+
R
GT
R
S
S-
–
+
V
OUT
R
G
GND
ZXCT1023
Document number: DS31997 Rev. 3 - 2
1 of 8
www.diodes.com
June 2011
© Diodes Incorporated
ZXCT1023
MICROPOWER FIXED GAIN OF 50 CURRENT MONITOR
Pin Descriptions
Pin Name
1
2
3
4
Pin Number
OUT
GND
S-
S+
Central Paddle
Description
Voltage output. The output voltage is referenced to GND.
The overall voltage gain is 50, i.e.,
V
OUT
= 50 x V
SENSE
where V
SENSE
= V
S+
- V
S-
Ground and substrate connection of device
High impedence negative sense voltage input
Positive sense input. Also acts as power supply pin to ZXCT1023
Substrate. Connect to GND
Absolute Maximum Ratings
Description
Voltage on S+ (Note 1)
Voltage on S- (Note 1, 2), OUT(Note 1)
V
SENSE
(Note 3)
Junction Temperature
Storage Temperature
Package Power Dissipation (T
A
= 25°C)
TDFN1218
ESD Ratings
Human Body Model
Machine Model
2000
150
Rating
-0.5 to 20
-0.5 V
S+
+0.5
-0.5 to +2.5
-40 to 125
-55 to 150
Unit
V
V
V
°C
°C
mW
V
V
These are stress ratings only. Operation outside the absolute maximum ratings may cause device failure. Operation at the absolute
maximum rating for extended periods may reduce device reliability.
Semiconductor devices are ESD sensitive and may be damaged by exposure to ESD events. Suitable ESD precautions should be taken
when handling and transporting these devices.
Notes:
1. Measured with respect to GND pin
2. Subject to absolute maximum V
SENSE
not being exceeded.
3. V
SENSE
is defined as the voltage difference across the sense resistor, R
S
.
4. The usable V
SENSE
range is limited by the output voltage range; and as such will be reduced at lower V
S+
values.
Recommended Operating Conditions
(T
A
= 25°C)
Symbol
V
S+
(Note 1)
V
SENSE
V
OUT
T
A
Parameter
Common-Mode Sense Input Range
Differential Sense Input Voltage Range
Output Voltage Range
Ambient Temperature Range
Min
2.5
0
0
-40
Max
20
380
(Note 4)
V
S-
- 1
85
Unit
V
mV
V
°C
ZXCT1023
Document number: DS31997 Rev. 3 - 2
2 of 8
www.diodes.com
June 2011
© Diodes Incorporated
ZXCT1023
MICROPOWER FIXED GAIN OF 50 CURRENT MONITOR
Electrical Characteristics
(T
A
= 25°C, V
S+
= 3.6V, V
SENSE
= 50mV, unless otherwise stated)
Symbol
Parameter
Conditions
V
SENSE
= 0mV
V
SENSE
= 10mV
V
OUT
Output voltage
V
SENSE
= 30mV
V
SENSE
= 50mV
V
SENSE
= 100mV, V
S+
= 20V
TC
(Note 5)
I
Q
I
S-
Acc
Gain
R
OUT
BW
PSRR
(Note 6)
Notes
5.
6.
Min.
425
1.41
2.425
4.85
Limits
Typ.
0.3
500
1.5
2.5
5
50
Max.
50
575
1.59
2.575
5.15
300
8
100
3
Unit
mV
V
Output voltage temperature
coefficient
Ground pin current
SENSE- input current
Accuracy
V
OUT
/V
SENSE
Output resistance
Bandwidth
V
SENSE
(DC) = 10mV
V
SENSE
(DC) = 50mV
50
V
SENSE
= 0V
V
SENSE
= 0V
V
SENSE
= 50mV
V
SENSE
= 50mV
-3
ppm/°C
μA
nA
%
V/V
kΩ
kHz
MHz
dB
3.5
50
15
300
1
60
Power supply rejection ratio V
SENSE
= 30mV, V
S+
= 2.5 to 20V
TC limits are determined by characterization.
PSRR is defined as change in output voltage per change in S+ voltage, V
S+
.
ZXCT1023
Document number: DS31997 Rev. 3 - 2
3 of 8
www.diodes.com
June 2011
© Diodes Incorporated
ZXCT1023
MICROPOWER FIXED GAIN OF 50 CURRENT MONITOR
Typical DC Characteristics
2.5
3%
V
SENSE
= 0V, V
S+
= 3.6V
T
A
= -40°C
T
A
= 85°C
Differential Gain Error
2%
T
A
= -40°C
1%
Vs+ = 3.6v
Relative to gain = 50
2
T
A
= 0°C
I
S+
(µA)
1.5
T
A
= 25°C
0%
T
A
= 0°C
T
A
= 85°C
1
0.5
-1%
0
2
4
6
8
10
12
14
16
18
20
-2%
0
10
V
S+
(V)
20
30
V
SENSE
(mV)
40
50
S+ Input Current vs. Supply voltage
70
Differential Gain (ΔV
OUT
/ΔV
SENSE
)
T
A
= 0°C
-40°C
60
25°C
50
85°C
2.5
V
OUT
(V)
2
3.5
Normalised Gain Error vs. Sense Voltage
V
S+
= 3.6V
3
T
A
= 85°C
T
A
= 25°C
T
A
= 0°C
T
A
= -40°C
V
S+
= 3.6V
40
1.5
1
30
0.5
0
20
0
2
4
V
SENSE
(mV)
6
8
10
0
10
20
30
V
SENSE
(mV)
40
50
60
Differential Gain vs. Sense Voltage
3
T
A
= 25°C
2.5
2
V
SENSE
= 30mV
1.5
1
V
SENSE
= 10mV
0.5
0
2
4
6
8
10
12
14
16
18
20
-0.6%
-40
-0.4%
ΔV
OUT
%Error
0.6%
Output Voltage vs. Sense Voltage
V
SENSE
= 50mV
0.4%
10mV
0.2%
V
S+
=3.6V
w.r.t. V
OUT
at 25°C
V
SENSE
= 10mV, 30mV, 50mV
V
OUT
(V)
0.0%
30mV
50mV
50mV
30mV
-0.2%
-15
V
S+
(V)
10
35
Temperature (°C)
60
85
Output Voltage vs. Input voltage
Relative Output Voltage Change vs. Temperature
ZXCT1023
Document number: DS31997 Rev. 3 - 2
4 of 8
www.diodes.com
June 2011
© Diodes Incorporated
ZXCT1023
MICROPOWER FIXED GAIN OF 50 CURRENT MONITOR
Typical AC Characteristics
40
V
SENSE
= 50mV
30
20
Gain (dB)
10
0
-10
-20
10E+0
V
S+
=3.6V
T
A
=25°C
V
SENSE
= 10mV
PSRR (dB)
70
60
50
40
30
V
S+
=
20
10
0
0.01
V
S+
= 10V
T
A
= 25°C
V
SENSE
= 50mV
100E+0
1E+3
10E+3
100E+3
frequency (Hz)
1E+6
10E+
0.1
1
10
Frequency (kHz)
100
1000
Small Signal Frequency Response
25
20
15
Input (mV)
10
5
0
0
-5
50
100
150
Time (µs)
200
250
Input
Output
V
S+
=3.6V, T
A
= 25°C
V
SENSE
= 20mV
Power Supply Rejection Ratio
1.2
1
0.8
Input (mV)
Output (V)
0.6
0.4
0.2
0
0
300
-0.2
-10
0
50
100
Time (µs)
150
0.0
-0.5
200
60
50
40
30
20
Output
Input
V
S+
=3.6V, T
A
= 25°C
V
SENSE
= 50mV
3.0
2.5
2.0
1.5
1.0
0.5
Output (V)
V
OUT
(V)
10
Large Signal Pulse Response 20mV
56
55
Sense voltage (mV)
54
53
52
51
50
49
0
50
100
time (µs)
150
Output
Input
V
S+
=3.6V, T
A
=25°C
V
SENSE
= 50mV(DC) + 5mV
Large Signal Pulse Response 50mV
2.80
2.75
Output voltage (V)
2.70
2.65
2.60
2.55
2.50
2.45
200
51
50
49
V
SENSE
(mV)
48
Input
2.35
Output
2.30
2.25
2.20
150
47
46
45
44
0
25
50
75
time (µs)
100
125
V
S+
=3.6V, T
A
=25°C
V
SENSE
= 50mV(DC) - 5mV pulse
2.55
2.50
2.45
2.40
Small Signal Positive Pulse Response
Small Signal Negative Pulse Response
ZXCT1023
Document number: DS31997 Rev. 3 - 2
5 of 8
www.diodes.com
June 2011
© Diodes Incorporated
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