ZXCT1080

ZXCT1080
HIGH VOLTAGE HIGH-SIDE CURRENT MONITOR
Description
Pin Assignments
The ZXCT1080 is a high side current sense monitor with a
gain of 10 and a voltage output. Using this device eliminates
VCC
the need to disrupt the ground plane when sensing a load
current.
1
5 S-
GND 2
The wide input voltage range of 60V down to as low as 3V
make it suitable for a range of applications; including systems
OUT 3
operating from industrial 24 to 28V rails and 48V rails.
74 S+
The separate supply pin (VCC) allows the device to continue
functioning under short circuit conditions, giving an end stop
voltage at the output.
The
ZXCT1080
has
an
extended
ambient
operating
temperature range of -40°C to 125°C enabling it to be used in
a wide range of applications including automotive.
Features
Applications
•
3V to 60V continuous high side voltage
•
Industrial applications current measurement
•
Accurate high-side current sensing
•
Battery management
•
-40 to 125°C temperature range
•
Over-current measurement
•
AEC-Q100 Grade 1 qualified
•
Power management
•
Output voltage scaling x10
•
Automotive current measurement
•
4.5V to 12V VCC range
•
Low quiescent current:
•
o
80μA supply pin
o
27μA IS+
SOT25 package
Typical Application Circuit
RSENSE
VIN
5
4
VCC
ZXCT1080
Document number: DS33454 Rev. 4 - 2
S+
1
S-
ZXCT1080
GND
OUT
2
3
1 of 11
www.diodes.com
VOUT
December 2011
© Diodes Incorporated
ZXCT1080
HIGH VOLTAGE HIGH-SIDE CURRENT MONITOR
Pin Descriptions
Pin
Name
1
VCC
This is the analogue supply and provides power to internal circuitry
Description
2
3
GND
OUT
4
S+
5
S-
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
Absolute Maximum Ratings (TA = 25°C)
Parameter
Continuous voltage on S- and S+
Voltage on all other pins
Rating
Unit
-0.6 and 65
-0.6 and +14
V
V
Differential sense voltage, VSENSE (Note 1)
800
mV
Operating temperature
-40 to +125
°C
Storage Temperature
-55 to +150
°C
125
300
°C
Maximum Junction Temperature
Package Power Dissipation (Note 2)
mW
(@ TA = 25°C)
Operation above the absolute maximum rating may cause device failure. Operation at the absolute maximum ratings,
for extended periods, may reduce device reliabilty.
Note:
1. VSENSE is defined as the differentail voltage between S+ and S- pins
2. Assumes θJA = 420°C/W
Recommended Operating Conditions
Symbol
Common-mode Sense+ Input Range
VCC
Supply Voltage Range
VSENSE
Note:
Parameter
VIN
Differential Sense Input Voltage Range
Min
Max
Units
3
60
V
4.5
12
V
0
0.15
V
VOUT
Ouput Voltage Range (Note 3)
0
1.5
V
TA
Ambient Temperature Range
-40
125
°C
3. Based on 10x VSENSE
ZXCT1080
Document number: DS33454 Rev. 4 - 2
2 of 11
www.diodes.com
December 2011
© Diodes Incorporated
ZXCT1080
HIGH VOLTAGE HIGH-SIDE CURRENT MONITOR
Electrical Characteristics
TA = 25°C, VIN = 12V, VCC = 5V, VSENSE (Note 4) = 100mV (unless otherwise specified)
Symbol
Parameter
ICC
VCC Supply Current
IS+
S+ Input Current
IS-
S- Input Current
VO(0)
Zero VSENSE error
(Note 4, 6)
VO(10)
Output Offset Voltage
(Note 7)
Gain
ΔVOUT/ΔVSENSE (Note 4)
VOUT TC
(Note 8)
Conditions
VCC = 12V,
VSENSE =0V (Note 4)
TA
Min
(Note 5)
Typ.
25°C
40
80
Full range
Max
Units
(Note 5)
120
145
µA
25°C
Full range
15
27
42
60
µA
25°C
15
40
80
nA
25°C
0
35
mV
25°C
-25
+25
VSENSE = 10mV to 150mV
Full range
25°C
-55
9.9
+55
10.1
(Note 4)
Full range
9.8
VSENSE = 0V (Note 4)
VSENSE = 10mV (Note 4)
VOUT variation with
temperature
10
10.2
30
mV
V/V
ppm/°C
ACC
Total output error
IOH
Output Source Current
ΔVOUT = -30mV
1
mA
20
µA
-3
3
%
Output Sink Current
ΔVOUT = +30mV
PSRR
VCC Supply Rejection
Ration
VCC = 4.5V to 12V
54
60
dB
CMRR
Common-Mode Sense
Rejection Ratio
VIN = 60V to 3V
68
80
dB
-3dB small signal
bandwidth
VSENSE (AC) = 10mVpp
(Note 4)
500
kHz
IOL
BW
Notes:
4. VSENSE = "VS+" - "VS-"
5. All Min and Max specifications over full temperature range are guaranteed by design and characterization
6. The ZXCT1080 operates from a positive power rail and the internal voltage-current converter current flow is unidirectional; these result in the output
offset voltage for VSENSE = 0V always being positive.
7. For VSENSE > 10mV, the internal voltage-current converter is fully linear. This enables a true offset to be defined and used. VO(10) is expressed
as the variance about an output voltage of 100mV>
8. Temperature dependent measurements are extracted from characterization and simulation results.
ZXCT1080
Document number: DS33454 Rev. 4 - 2
3 of 11
www.diodes.com
December 2011
© Diodes Incorporated
ZXCT1080
HIGH VOLTAGE HIGH-SIDE CURRENT MONITOR
Typical Characteristics
Test conditions unless otherwise stated:TA = 25°C, VIN = 12V, VCC = 5V, VSENSE+ = 12V, VSENSE = 100mV
70
20
IS+ INPUT CURRENT (µA)
ICC, SUPPLY CURRENT (µA)
TA = 125°C
65
TA = 85°C
60
T A = 25°C
TA = 0°C
55
TA = -40°C
TA = 125°C
TA = 25°C
TA = -40°C
10
VCC = 5V
VSENSE = 0mV
VS+ = 12V
VSENSE = 0mV
50
2
15
4
6
8
10
VCC, SUPPLY VOLTAGE (V)
Fig. 1 Supply Current
5
12
0
5
10 15
20 25
30 35
VS+, INPUT CURRENT (V)
Fig. 2 Input Current
40
40
35
IS- SENSE CURRENT (nA)
IS+ INPUT CURRENT (µA)
20
15
10
30
25
20
15
10
VCC = 5V
VSENSE = 0mV
T AMB = 25°C
5
5
-50
-25
0
25
50
75 100
TA, TEMPERATURE(°C)
Fig. 3 Input Current
0
0
125
1.6
1.8
1.4
1.6
5
10 15
20 25
30
VS+, INPUT VOLTAGE (V)
Fig. 4 Sense Current
1.2
1.0
0.8
0.6
0.4
VOUT, OUTPUT VOLTAGE (V)
VOUT, OUTPUT VOLTAGE (V)
VSENSE = 150mV
0.2
ZXCT1080
Document number: DS33454 Rev. 4 - 2
VCC = 5V
VS+ = 12V
1.2
VSENSE = 100mV
1.0
0.8
0.6
VSENSE = 50mV
0.4
0.0
-50
4 of 11
www.diodes.com
40
1.4
0.2
0.0
0.00 0.02 0.04 0.06 0.08 0.10 0.12 0.14
VSENSE,SENSE VOLTAGE (V)
Fig. 5 Output Voltage
35
VSENSE = 10mV
-25
0
25
50 75
100
TA, TEMPERATURE (°C)
Fig. 6 Output Voltage
125
December 2011
© Diodes Incorporated
ZXCT1080
HIGH VOLTAGE HIGH-SIDE CURRENT MONITOR
Typical Characteristics (cont.)
Test conditions unless otherwise stated:TA = 25°C, VIN = 12V, VCC = 5V, VSENSE+ = 12V, VSENSE = 100mV
0
VIN = 12V
VCC = 5V
VSENSE = 100mV
25
TA = 125°C
-1
ΔOUTPUT VOLTAGE (mV)
ΔVOUT, OUTPUT VOLTAGE (mV)
30
T A = 85°C
20
TA = 25°C
TA = 0°C
15
TA = -40°C
10
5
-2
TA = -40°C
-3
TA = 0°C
-4
TA = 25°C
-5
TA = 85°C
VIN = 12V
VCC = 5V
VSENSE = 100mV
-6
0
0
-7
0.0
5
10
15
20
25
30
IOL , OUTPUT SINK CURRENT (µA)
Fig. 7 Output Current Sink
T A = 125°C
0.2 0.4
0.6
0.8 1.0
1.2 1.4
IOH, OUTPUT SOURCE CURRENT (mA)
Fig. 8 Output Current Source
10.1
12m
ΔOUTPUT VOLTAGE (V)
GAIN
10.0
9.9
9.8
9.7
0
VSENSE = 150mV
10m
8m
VSENSE = 100mV
VSENSE = 50mV
VSENSE = 10mV
6m
4m
2m
VCC = 5V
TAMB = 25°C
0
50m
100m
VSENSE, SENSE VOLTAGE (V)
Fig. 9 Differential gain
150m
0
5
10
15 20 25
30
VS+, INPUT VOLTAGE (V)
Fig. 10 Output Voltage
35
40
ΔOUTPUT VOLTAGE (V)
6m
4m
2m
0
-2m
-4m
0
5
10
15 20 25 30
VS+, INPUT VOLTAGE (V)
Fig. 11 Output Voltage
ZXCT1080
Document number: DS33454 Rev. 4 - 2
35
40
5 of 11
www.diodes.com
December 2011
© Diodes Incorporated
ZXCT1080
HIGH VOLTAGE HIGH-SIDE CURRENT MONITOR
Typical Characteristics (cont.)
Test conditions unless otherwise stated:TA = 25°C, VIN = 12V, VCC = 5V, VSENSE+ = 12V, VSENSE = 100mV
8
14
VIN = 12V
T A = 25°C
12
6
TA = 125°C
TA = 85°C
10
ΔVOUT (mV)
ΔVOUT (mV)
8
4
2
T A = 25°C
6
TA = 0°C
T A = -40°C
4
2
VSENSE = 10mV to 150mV
0
0
-2
VIN = 12V
VSENSE = 5V
-4
-2
6
8
10
VCC, SUPPLY VOLTAGE (V)
Fig. 12 Normalized Output Voltage
20
1.5
15
1.0
10
VIN = 12V
VCC = 5V
TA = 25C
VSENSE = 10mVp-p
5
1k
10k
100k
1M
FREQUENCY (Mhz)
Fig. 14 Small Signal Bandwidth
60
6
8
10
VCC, SUPPLY VOLTAGE (V)
Fig. 13 Normalized Output Voltage
12
0.5
0.0
-2
10M
VIN = 12V
VIN PEAK = 60V
VCC = 5V
50
0
2
4
6
8 10 12 14
TIME (µs)
Fig. 15 Large Signal Pulse Response
0
2
4
1.00
RSENSE = 0.1Ω
RLOAD = 30Ω
VIN
40
VOLTAGE (V)
VOLTAGE (V)
4
12
VOLTAGE (V)
GAIN (dB)
4
30
20
0.95
VOUT
10
0.90
0
0
200
400
600
TIME (ms)
Fig. 16 Load Dump Waveform
ZXCT1080
Document number: DS33454 Rev. 4 - 2
-2
6 of 11
www.diodes.com
6
8 10 12 14
TIME (µs)
Fig. 17 Small Signal Pulse Response
December 2011
© Diodes Incorporated
ZXCT1080
HIGH VOLTAGE HIGH-SIDE CURRENT MONITOR
Typical Characteristics (cont.)
Test conditions unless otherwise stated:TA = 25°C, VIN = 12V, VCC = 5V, VSENSE+ = 12V, VSENSE = 100mV
70
80
70
60
50
50
PSRR (dB)
CMRR (dB)
60
40
30
0
10
30
20
20
10
40
VIN = 12V
VSENSE = 100mV
VCC = 5V
100
1k
10k
100k
FREQUENCY (Hz)
Fig. 18 Common Mode Rejection
ZXCT1080
Document number: DS33454 Rev. 4 - 2
10
1M
7 of 11
www.diodes.com
0
100
VIN = 12V
VSENSE = 100mV
VCC = 5V
1k
10k
100k
FREQUENCY (Hz)
Fig. 19 Supply Rejection
1M
December 2011
© Diodes Incorporated
ZXCT1080
HIGH VOLTAGE HIGH-SIDE CURRENT MONITOR
Application Information
The ZXCT1080 has been designed to allow it to operate with 5V supply rails while sensing common mode signals up to 60V.
This makes it well suited to a wide range of industrial and power supply monitoring applications that require the interface to
5V systems while sensing much higher voltages.
To allow this its VCC pin can be used independently of S+.
Figure 1 shows the basic configuration of the ZXCT1080.
Fig. 20 Typical Configuration of ZXCT1080
Load current from the input is drawn through RSENSE developing a voltage VSENSE across the inputs of the ZXCT1080.
The internal amplifier forces VSENSE across internal resistance RGT causing a current to flow through MOSFET M1. This
current is then converted to a voltage by RG. A ratio of 10:1 between RG and RGT creates the fixed gain of 10. The output is
then buffered by the unity gain buffer.
The gain equation of the ZXCT1080 is:
V OUT = IL RSENSE
RG
× 1 = IL x RSENSE × 10
RGT
The maximum recommended differential input voltage, VSENSE, is 150mV; it will however withstand voltages up to 800mV.
This can be increased further by the inclusion of a resistor, RLIM, between S- pin and the load; typical value is of the order of
10k.
ZXCT1080
Document number: DS33454 Rev. 4 - 2
8 of 11
www.diodes.com
December 2011
© Diodes Incorporated
ZXCT1080
HIGH VOLTAGE HIGH-SIDE CURRENT MONITOR
Application Information (cont.)
Fig. 21 Protection/Error Sources for ZXCT1080
Capacitor CD provides high frequency transient decoupling when used with RLIM; typical values are of the order 10pF.
For best performance RSENSE should be connected as close to the S+ (and SENSE) pins; minimizing any series resistance
with RSENSE.
When choosing appropriate values for RSENSE a compromise must be reached between in-line signal loss (including potential
power dissipation effects) and small signal accuracy.
Higher values for RSENSE gives better accuracy at low load currents by reducing the inaccuracies due to internal offsets. For
best operation the ZXCT1080 has been designed to operate with VSENSE of the order of 50mV to 150mV.
Current monitors' basic configuration is that of a unipolar voltage to current to voltage converter powered from a single supply
rail. The internal amplifier at the heart of the current monitor may well have a bipolar offset voltage but the output cannot go
negative; this results in current monitors saturating at very low sense voltages.
As a result of this phenomenon the ZXCT1080 has been specified to operate in a linear manner over a VSENSE range of
10mV to 150mV range, however it will still be monotonic down to VSENSE of 0V.
It is for this very reason that Diodes has specified an input offset voltage (VO(10)) at 10mV. The output voltage for any VSENSE
voltage from 10mV to 150mV can be calculated as follows:
VOUT = (VSENSE ) × G + V (10 )
Alternatively the load current can be expressed as:
IL =
(VOUT − VO(10 ))
GxRSENSE
ZXCT1080
Document number: DS33454 Rev. 4 - 2
9 of 11
www.diodes.com
December 2011
© Diodes Incorporated
ZXCT1080
HIGH VOLTAGE HIGH-SIDE CURRENT MONITOR
Ordering Information
Device
AEC-Q100
Package
Part Mark
Reel Size
Tape Width
(mm)
Quantity per
Reel
ZXCT1080E5TA
Grade 1
SOT25
1080
7
8
3000
Package Outline Dimensions (All Dimensions in mm)
SOT25
A
B C
H
K
J
ZXCT1080
Document number: DS33454 Rev. 4 - 2
M
N
D
L
10 of 11
www.diodes.com
SOT25
Dim Min Max Typ
A
0.35 0.50 0.38
B
1.50 1.70 1.60
C
2.70 3.00 2.80
D
⎯
⎯ 0.95
H
2.90 3.10 3.00
J
0.013 0.10 0.05
K
1.00 1.30 1.10
L
0.35 0.55 0.40
M
0.10 0.20 0.15
N
0.70 0.80 0.75
0°
8°
α
⎯
All Dimensions in mm
December 2011
© Diodes Incorporated
ZXCT1080
HIGH VOLTAGE HIGH-SIDE CURRENT MONITOR
IMPORTANT NOTICE
DIODES INCORPORATED MAKES NO WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, WITH REGARDS TO THIS
DOCUMENT, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
PARTICULAR PURPOSE (AND THEIR EQUIVALENTS UNDER THE LAWS OF ANY JURISDICTION).
Diodes Incorporated and its subsidiaries reserve the right to make modifications, enhancements, improvements, corrections or other
changes without further notice to this document and any product described herein. Diodes Incorporated does not assume any liability
arising out of the application or use of this document or any product described herein; neither does Diodes Incorporated convey any
license under its patent or trademark rights, nor the rights of others. Any Customer or user of this document or products described
herein in such applications shall assume all risks of such use and will agree to hold Diodes Incorporated and all the companies
whose products are represented on Diodes Incorporated website, harmless against all damages.
Diodes Incorporated does not warrant or accept any liability whatsoever in respect of any products purchased through unauthorized
sales channel.
Should Customers purchase or use Diodes Incorporated products for any unintended or unauthorized application, Customers shall
indemnify and hold Diodes Incorporated and its representatives harmless against all claims, damages, expenses, and attorney fees
arising out of, directly or indirectly, any claim of personal injury or death associated with such unintended or unauthorized application.
Products described herein may be covered by one or more United States, international or foreign patents pending. Product names
and markings noted herein may also be covered by one or more United States, international or foreign trademarks.
LIFE SUPPORT
Diodes Incorporated products are specifically not authorized for use as critical components in life support devices or systems without
the express written approval of the Chief Executive Officer of Diodes Incorporated. As used herein:
A. Life support devices or systems are devices or systems which:
1. are intended to implant into the body, or
2. support or sustain life and whose failure to perform when properly used in accordance with instructions for use provided
in the labeling can be reasonably expected to result in significant injury to the user.
B.
A critical component is any component in a life support device or system whose failure to perform can be reasonably expected
to cause the failure of the life support device or to affect its safety or effectiveness.
Customers represent that they have all necessary expertise in the safety and regulatory ramifications of their life support devices or
systems, and acknowledge and agree that they are solely responsible for all legal, regulatory and safety-related requirements
concerning their products and any use of Diodes Incorporated products in such safety-critical, life support devices or systems,
notwithstanding any devices- or systems-related information or support that may be provided by Diodes Incorporated. Further,
Customers must fully indemnify Diodes Incorporated and its representatives against any damages arising out of the use of Diodes
Incorporated products in such safety-critical, life support devices or systems.
Copyright © 2011, Diodes Incorporated
www.diodes.com
ZXCT1080
Document number: DS33454 Rev. 4 - 2
11 of 11
www.diodes.com
December 2011
© Diodes Incorporated