MIC803-31D3VC3 TR Micrel Inc, MIC803-31D3VC3 TR Datasheet - Page 8

• Manufacturer Part Number: MIC803-31D3VC3 TR
• Description: IC MPU SUPERVISOR SC70-3
• Manufacturer: Micrel Inc
• Type: Simple Reset/Power-On Resetr

Specifications of MIC803-31D3VC3 TR

• Number Of Voltages Monitored: 1
• Output: Open Drain or Open Collector
• Reset: Active Low
• Reset Timeout: 140 ms Minimum
• Voltage - Threshold: 3.08V
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: SC-70, SOT-323
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 576-3815-2

Micrel, Inc.
Application Information
Microprocessor Reset
The /RESET pin is asserted whenever V
the Reset Threshold Voltage, V
remains asserted for the duration of the Reset Timeout
Period (t
Threshold Voltage. The reset function ensures the
microprocessor is properly reset and powers up in a
known condition after a power failure. /RESET will
remain valid with V
The /RESET output is a simple open-drain N-channel
MOSFET structure. A pull-up resistor must be used to
pull this output up to some voltage. For most
applications, this voltage will be the same power supply
that supplies V
is possible, however, to tie this resistor to some other
voltage. This will allow the MIC803 to monitor one
voltage while level-shifting the /RESET output to some
other voltage. The pull-up voltage must be limited to
5.5V. The resistor must be small enough to supply
current to the inputs and leakage paths that are driven
by the /RESET output.
/RESET Valid at Low Voltage
As V
pull the /RESET output low, and the pull-up resistor will
pull the output high. The value of the pull-up resistor and
the voltage it is connected to will affect the point at which
this happens.
December 2010
Figure 1. MIC803 used in a Multiple Supply System
CC
drops to 0V, the MIC803 will no longer be able to
RESET
) after V
CC
to the MIC803. As shown in Figure 1, it
CC
as low as 1.0V.
CC
has risen above the Reset
TH
. The /RESET pin
CC
falls below
8
Wire OR’ing The /RESET Output
Since the /RESET output is open-drain, several reset
sources can be wire-ORed, in parallel, to allow resets
from multiple sources.
V
The MIC803 is relatively immune to negative-going V
glitches below the Reset Threshold. See the Typical
Characteristic Curve, Maximum Transient Duration vs
Overdrive on page 6 of the datasheet. As shown in
Figure 3, the Overdrive Voltage is the difference
between the Threshold Voltage and the minimum point
of the V
duration of 15μs or less will not cause a reset. If
additional transient immunity is needed, a 0.1μF bypass
capacitor can be placed as close as possible to the
MIC803 on the V
CC
Transients
CC
glitch. Typically, an overdrive of 100mV, with
Figure 2. /RESET at falling V
CC
Figure 3. V
pin.
CC
Transient
M9999-122310-A
CC
MIC803
CC