zxct1008 Zetex Semiconductors plc., zxct1008 Datasheet - Page 5

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

ISSUE 4 - JULY 2007
POWER DISSIPATION
The maximum allowable power dissipation of the
device for normal operation (Pmax), is a function of
the package junction to ambient thermal resistance
(θja), maximum junction temperature (Tjmax), and
ambient temperature (Tamb), according to the
expression:
P
The device power dissipation, P
expression:
P
max
D
=I
out
= (Tj
.(V
in
max
-V
out
– T
) Watts
amb
) / θ
ja
D
is given by the
5
APPLICATIONS INFORMATION
The following lines describe how to scale a load
current to an output voltage.
E.g.
A 1A current is to be represented by a 100mV output
voltage:
1) Choose the value of R
For example V
R
2) Choose R
Rearranging
R
R
sense
out
out
V
when V
sense
= V
= 0.1 / (0.1 x 0.01) = 100 Ω
= 0.1/1.0 => 0.1 Ω
out
> 500mV at full load.
sense
V
/(V
out
1
out
for R
sense
sense
V
= 100mV.
to give V
= 0.01 x V
sense
out
= 100mV at 1.0A.
x 0.01)
gives:
= V
out
sense
in
sense
= 100mV,
- V
to give 50mV >
load
x R
ZXCT1008
out
1