Stresses above those listed under ABSOLUTE MAXIMUM RATINGS may cause permanent device failure. Functionality at or above these limits is not implied. Exposure to absolute
maximum ratings for extended periods may affect device reliability. Operating ranges define those limits between which the functionality of the device is guaranteed.
Electrical Characteristics
VCC = 3.3V, T
A
= Operating Temperature Range, unless otherwise noted.
Parameter
Operating Voltage Range, VCC
Supply Current, ICC
Reset Voltage Threshold, VTH
Reset Timeout Period
RESET Output Voltage, VOH
RESET Output Voltage, VOL
ISource = 800µA
VCC=VTH Min., ISink=1.2mA
VCC>1.4V, ISink =50µA
MIC1815-10
MIC1815-20
2.80
2.47
100
VCC - 1.5V
0.4
0.3
Conditions
TA = 0°C to 70°C
TA = -40°C to 85°C
Min
1.4
1.6
9
2.88
2.55
150
Typ
Max
5.5
5.5
20
2.97
2.64
250
Units
V
µA
V
ms
V
V
2
MIC1815 Microprocessor Reset Circuit
Pin Functions
Pin Name
RESET
VCC
GND
Pin No.
1
2
3
RESET goes low if VCC falls below the reset threshold and remains asserted for one
reset timeout period (100ms min.) after VCC exceeds the reset threshold.
Power supply input, 3.3V.
IC Ground Pin.
3
MIC1815 Microprocessor Reset Circuit
Block Diagram
VCC (2)
Reset
Threshold (VTH)
+
-
RESET
GENERATOR
RESET (1)
GND (3)
Figure 1. MIC1815 Block Diagram
4
MIC1815 Microprocessor Reset Circuit
Circuit Description
Microprocessor Reset
The RESET pin is asserted whenever VCC falls below
the reset threshold voltage. The reset pin remains
asserted for a period of 150ms after VCC has risen
above the reset threshold voltage. The reset function
ensures the microprocessor is properly reset and powers
up into a known condition after a power failure. RESET
will remain valid with VCC as low as 1.4V.
VCC Transients
The MIC1815 is relatively immune to negative-going
VCC glitches below the reset threshold. Typically, a
negative-going transient 125mV below the reset
threshold with a duration of 50µs or less will not cause
an unwanted reset.
8++
8JDH
J
8JDH
J
4-5-6
Figure 2. Reset Timing Diagram
VCC
VCC
VCC
µP
RESET
100K
MIC1815
RESET
RESET Valid to 0V
A resistor can be added from the RESET pin to ground
to ensure the RESET output remains low with V CC
down to 0V. A 100KΩ resistor connected from RESET
to ground is recommended. The size of the resistor
should be large enough to not load the RESET output
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