zxct1008 Zetex Semiconductors plc., zxct1008 Datasheet - Page 7

• Manufacturer Part Number: zxct1008
• Description: Zxct1008 - Automotive High-side Current Monitor
• Manufacturer: Zetex Semiconductors plc.

ISSUE 4 - JULY 2007
APPLICATIONS INFORMATION
PCB trace shunt resistor for low
cost solution.
The figure below shows output characteristics of the
device when using a PCB resistive trace for a low cost
solution in replacement for a conventional shunt
resistor. The graph shows the linear rise in voltage
across the resistor due to the PTC of the material and
demonstrates how this rise in resistance value over
temperature compensates for the NTC of the device.
The figure opposite shows a PCB layout suggestion.
The resistor section is 25mm x 0.25mm giving
approximately 150mΩ using 1oz copper. The data
for the normalised graph was obtained using a 1A
load current and a 100Ω output resistor. An
electronic version of the PCB layout is available at
www.zetex.com/isense
1.4
1.2
1.0
0.8
-40 -20
Effect of Sense Resistor Material
on Temperature Performance
0
Temperature (°C)
20
Voltage across
Copper Sense
Resistor
40
V
Sense Resistor
OUT
with Ideal
60
80
V
Sense Resistor
OUT
100 120 140
with Copper
7
Actual Size
GND
Vout
ZXCT1009
Vin
Load
Layout shows area of shunt
resistor compared to SOT23
package. Not actual size
GND
Vout
ZXCT1009
ZXCT1008
Vin
Load