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 = 5V for MIC8--L/M/J, VCC = 3.3V for MIC8--S/T, VCC = 3V for MIC8--R, T
A
= Operating Temperature Range, unless
otherwise noted.
Parameter
Operating Voltage Range, VCC
Supply Current, ICC
Reset Voltage Threshold, VTH
Conditions
TA = 0°C to 70°C
TA = -40°C to 85°C
MIC809L/M/J, MIC810L/M/J
VCC < 3.6V, MIC809R/S/T, MIC810R/S/T
MIC809L, MIC810L
MIC809M, MIC810M
MIC809J, MIC810J
MIC809T, MIC810T
MIC809S, MIC810S
MIC809R, MIC810R
4.50
4.25
3.89
3.00
2.85
2.55
140
ISource = 800µA, MIC809L/M/J
ISource = 500µA, MIC809R/S/T
VCC=VTH Min., ISink=3.2mA, MIC809L/M/J
VCC=VTH Min., ISink =1.2mA, MIC809R/S/T
VCC>1.4V, ISink =50µA, TA = 0°C to 70°C
VCC>1.6V, ISink =50µA, TA = -40°C to 85°C
1.8V < VCC < VTH Min.,
ISource = 150µA
ISink=3.2mA, MIC810L/M/J
ISink=1.2mA, MIC810R/S/T
0.8 X VCC
0.4
0.3
VCC - 1.5V
0.8 X VCC
0.4
0.3
0.3
0.3
Min
1.4
1.6
9
6
4.63
4.38
4.00
3.08
2.93
2.63
240
Typ
Max
5.5
5.5
15
10
4.75
4.50
4.10
3.15
3.00
2.70
560
Units
V
µA
V
Reset Timeout Period
RESET Output Voltage, VOH
RESET Output Voltage, VOL
ms
V
V
RESET Output Voltage, VOH
RESET Output Voltage, VOL
V
V
2
MIC809/MIC810 Microprocessor Reset Circuits
Pin Functions
Pin No.
Pin Name
GND
RESET
MIC809
1
2
MIC810
1
N/A
IC Ground Pin.
RESET goes low if VCC falls below the reset threshold and remains
asserted for one reset timeout period (140ms min.) after VCC exceeds
the reset threshold.
RESET goes high if VCC falls below the reset threshold and remains
asserted for one reset timeout period (140ms min.) after VCC exceeds
the reset threshold.
Power supply input, 3V, 3.3V or 5V.
RESET
N/A
2
VCC
3
3
3
MIC809/MIC810 Microprocessor Reset Circuits
Block Diagram
VCC (3)
Reset
Threshold (V)
+
-
RESET
GENERATOR
RESET (2)
RESET (MIC810)
GND (1)
Figure 1. MIC809/810 Block Diagram
4
MIC809/MIC810 Microprocessor Reset Circuits
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 240ms 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 MIC809/MIC810 are 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 (25µs for
MIC8__R/S/T) or less will not cause an unwanted reset.
Interfacing to Bidirectional Reset Pins
The MIC809/MIC810 can interface with
µPs
with
bidirectional reset pins by connecting a 4.7KΩ resistor in
series with the MIC809/MIC810 output and the
µP
reset
pin.
8++
8JDH
J
8JDH
J
4-5-6
Figure 2. Reset Timing Diagram
VCC
VCC
VCC
µP
RESET
100K
MIC809
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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