Datasheet

© 2008 Microchip Technology Inc. DS22114A-page 17
MCP9509/10
For example, at room temperature, when output
asserts Active-Low and maximum I
DD
= 50 µA,
V
DD
=5.5V, V
OL
= 0.3V and I
OUT
= 5 mA (see specifi-
cation table), the self heating due to power dissipation
(T
J
- T
A
) is ~0.4°C.
4.6.2 DRIVING OUTSET WITH A
MICROCONTROLLER I/O PIN
The OUTSET pin can be controlled using a Microcon-
troller input/output (I/O) pin. I/O levels HIGH and LOW
provide push-pull configuration with Active-High and
Active-Low outputs, respectively. The Open-Drain
output with internal pull-up resistor can be selected by
configuring the I/O pin as a High-Impedance Input. The
Open-Drain output can also be selected by forcing volt-
age level V
OSET
from a low impedance source. With
this configuration, there maybe some leakage current
due to impedance mismatch, (See Figure 4-2).
4.6.3 POWER SUPPLY REJECTION
The MCP9509/10 family of sensors are designed to
prevent false output trigger due to high frequency
power supply or system noise. Figure 4-7 shows
device performance with a high frequency signal added
on V
DD
. The output is not triggered due to the signal
added on V
DD
. With some applications, it is
recommended to add a bypass capacitor of 0.1 µF to
1µF.
FIGURE 4-7: Power Supply Rejection
(PSR).
0
1
2
3
4
5
6
10 100 1000 10 000 10 0000 1000000 10 000000
Frequency (Hz)
Output Voltage (V)
MCP9509/10 Power Supply Rejection
No False Trigger
10
100
1M
10M
1k
100
10
V
DD
= 5V + 400mV
AC
V
DD
= 5V + 400mV
SQR