April 2005 1
M0450-041405
MIC809/810
MIC809/810
Microprocessor Reset Circuits
General Description
The MIC809 and MIC810 are inexpensive microprocessor
supervisory circuits that monitor power supplies in micro-
processor based systems.
The function of these devices is to assert a reset if the power
supply drops below a designated reset threshold level. Several
different reset threshold levels are available to accommodate
3V, 3.3V or 5V powered systems.
The MIC809 has an active-low /RESET output, while the
MIC810 offers an active-high RESET output. The reset output
is guaranteed to remain asserted for a minimum of 140ms
after V
CC
has risen above the designated reset threshold
level. Having a push-pull output stage, the MIC809/810 does
not require a pull-up resistor at the output. The MIC809/810
comes in a 3-pin SOT-23 and SC-70 package.
The MIC809 is also available with a shorter reset timeout
(30ms min.). See the MIC809-5.
All support documentation can be found on Micrel’s web site
at www.micrel.com.
Typical Application
VCC
RESET
µP
RESET
VCC
MIC809
VCC
Features
• Precision voltage monitor for 3V, 3.3V or 5V power sup-
plies
• /RESET remains valid with V
CC
as low as 1.4V for SOT-
23 packaged part
• /RESET remains valid with VCC as low as 1V for SC70
packaged part
• Typically less than15µA supply current for SOT-23 pack-
aged part
• 5µ typical supply current for SC70 packaged part
• 140ms minimum reset pulse widths available
• Available in 3-pin SOT-23 and SC-70 package
Applications
• Portable equipment
• Intelligent instruments
• Critical microprocessor power monitoring
• Printers/computers
• Controllers
Micrel, Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com
MIC809/810 Micrel
M0450-041405
2
April 2005
Pin Description
Pin Number Pin Number Pin Name Pin Function
MIC809 MIC810
1 1 GND IC Ground Pin.
2 N/A /RESET /RESET goes low if V
CC
falls below the reset threshold and remains as-
serted for one reset timeout period (140ms min.) after V
CC
exceeds the reset
threshold.
N/A 2 RESET RESET goes high if V
CC
falls below the reset threshold and remains as-
serted for one reset timeout period (140ms min.) after V
CC
exceeds the reset
threshold.
3 3 VCC Power Supply Input.
Pin Confi guration
1
2
3VCC
GND
MIC809
RESET
1
2
3VCC
GND
MIC810
RESET
Pin Number Pin Number Pin Name Pin Function
MIC809 MIC810
N/A 2 RESET RESET goes high if V
3 3 VCC Power Supply Input.
Pin Number Pin Number Pin Name Pin Function
MIC809 MIC810
1 1 GND IC Ground Pin.
2 N/A /RESET /RESET goes low if V
N/A 2 RESET RESET goes high if V
3 3 VCC Power Supply Input.
Pin Number Pin Number Pin Name Pin Function
1 1 GND IC Ground Pin.
2 N/A /RESET /RESET goes low if V
N/A 2 RESET RESET goes high if V
3 3 VCC Power Supply Input.
Pin Number Pin Number Pin Name Pin Function
1 1 GND IC Ground Pin.
2 N/A /RESET /RESET goes low if V
N/A 2 RESET RESET goes high if V
3 3 VCC Power Supply Input.
MIC809 3-Lead SOT23
MIC809 3-Lead SC70
Ordering Information
Part Number
Threshold Operating
Lead Finish
3-lead SOT-23 Package 3-lead SC-70 Package
Marking Voltage Temp. Range
MIC809LU MIC809LBC3 IL 4.63 –40°C to +85°C Standard
MIC809MU MIC809MBC3 IM 4.38 –40°C to +85°C Standard
MIC809JU MIC809JBC3 IJ 4.00 –40°C to +85°C Standard
MIC809TU MIC809TBC3 IT 3.08 –40°C to +85°C Standard
MIC809SU MIC809SBC3 IS 2.93 –40°C to +85°C Standard
MIC809RU MIC809RBC3 IR 2.63 –40°C to +85°C Standard
MIC810LU MIC810LBC3 JL 4.63 –40°C to +85°C Standard
MIC810MU MIC810MBC3 JM 4.38 –40°C to +85°C Standard
MIC810JU MIC810JBC3 JJ 4.00 –40°C to +85°C Standard
MIC810TU MIC810TBC3 JT 3.08 –40°C to +85°C Standard
MIC810SU MIC810SBC3 JS 2.93 –40°C to +85°C Standard
MIC810RU MIC810RBC3 JR 2.63 –40°C to +85°C Standard
MIC809LUY MIC809LYC3
IL
4.63 –40°C to +85°C Pb-Free
MIC809MUY MIC809MYC3
IM
4.38 –40°C to +85°C Pb-Free
MIC809JUY MIC809JYC3
IJ
4.00 –40°C to +85°C Pb-Free
MIC809TUY MIC809TYC3
IT
3.08 –40°C to +85°C Pb-Free
MIC809SUY MIC809SYC3
IS
2.93 –40°C to +85°C Pb-Free
MIC809RUY MIC809RYC3
IR
2.63 –40°C to +85°C Pb-Free
MIC810LUY MIC810LYC3
JL
4.63 –40°C to +85°C Pb-Free
JL 4.63 –40°C to +85°C Pb-FreeJL
MIC810MUY MIC810MYC3
JM
4.38 –40°C to +85°C Pb-Free
MIC810JUY MIC810JYC3
JJ
4.00 –40°C to +85°C Pb-Free
MIC810TUY MIC810TYC3
JT
3.08 –40°C to +85°C Pb-Free
MIC810SUY MIC810SYC3
JS
2.93 –40°C to +85°C Pb-Free
MIC810RUY MIC810RYC3
JR
2.63 –40°C to +85°C Pb-Free
Note: Contact factory for SC70 packaged Pb-free options..
MIC809LU MIC809LBC3 IL 4.63 –40°C to +85°C Standard
MIC809MU MIC809MBC3 IM 4.38 –40°C to +85°C Standard
MIC809JU MIC809JBC3 IJ 4.00 –40°C to +85°C Standard
MIC809TU MIC809TBC3 IT 3.08 –40°C to +85°C Standard
MIC809SU MIC809SBC3 IS 2.93 –40°C to +85°C Standard
MIC809RU MIC809RBC3 IR 2.63 –40°C to +85°C Standard
MIC810LU MIC810LBC3 JL 4.63 –40°C to +85°C Standard
MIC810MU MIC810MBC3 JM 4.38 –40°C to +85°C Standard
MIC810JU MIC810JBC3 JJ 4.00 –40°C to +85°C Standard
MIC810TU MIC810TBC3 JT 3.08 –40°C to +85°C Standard
MIC810SU MIC810SBC3 JS 2.93 –40°C to +85°C Standard
MIC810RU MIC810RBC3 JR 2.63 –40°C to +85°C Standard
Threshold Operating
Marking Voltage Temp. Range
MIC809LU MIC809LBC3 IL 4.63 –40°C to +85°C Standard
MIC809MU MIC809MBC3 IM 4.38 –40°C to +85°C Standard
MIC809JU MIC809JBC3 IJ 4.00 –40°C to +85°C Standard
MIC809TU MIC809TBC3 IT 3.08 –40°C to +85°C Standard
MIC809SU MIC809SBC3 IS 2.93 –40°C to +85°C Standard
MIC809RU MIC809RBC3 IR 2.63 –40°C to +85°C Standard
MIC810LU MIC810LBC3 JL 4.63 –40°C to +85°C Standard
MIC810MU MIC810MBC3 JM 4.38 –40°C to +85°C Standard
MIC810JU MIC810JBC3 JJ 4.00 –40°C to +85°C Standard
MIC810TU MIC810TBC3 JT 3.08 –40°C to +85°C Standard
MIC810SU MIC810SBC3 JS 2.93 –40°C to +85°C Standard
MIC810RU MIC810RBC3 JR 2.63 –40°C to +85°C Standard
4.63 –40°C to +85°C Pb-Free
4.38 –40°C to +85°C Pb-Free
4.00 –40°C to +85°C Pb-Free
3.08 –40°C to +85°C Pb-Free
2.93 –40°C to +85°C Pb-Free
2.63 –40°C to +85°C Pb-Free
4.63 –40°C to +85°C Pb-Free
4.38 –40°C to +85°C Pb-Free
4.00 –40°C to +85°C Pb-Free
3.08 –40°C to +85°C Pb-Free
2.93 –40°C to +85°C Pb-Free
2.63 –40°C to +85°C Pb-Free
Lead Finish
MIC809LU MIC809LBC3 IL 4.63 –40°C to +85°C Standard
MIC809MU MIC809MBC3 IM 4.38 –40°C to +85°C Standard
MIC809JU MIC809JBC3 IJ 4.00 –40°C to +85°C Standard
MIC809TU MIC809TBC3 IT 3.08 –40°C to +85°C Standard
MIC809SU MIC809SBC3 IS 2.93 –40°C to +85°C Standard
MIC809RU MIC809RBC3 IR 2.63 –40°C to +85°C Standard
MIC810LU MIC810LBC3 JL 4.63 –40°C to +85°C Standard
MIC810MU MIC810MBC3 JM 4.38 –40°C to +85°C Standard
MIC810JU MIC810JBC3 JJ 4.00 –40°C to +85°C Standard
MIC810TU MIC810TBC3 JT 3.08 –40°C to +85°C Standard
MIC810SU MIC810SBC3 JS 2.93 –40°C to +85°C Standard
MIC810RU MIC810RBC3 JR 2.63 –40°C to +85°C Standard
4.63 –40°C to +85°C Pb-Free
4.38 –40°C to +85°C Pb-Free
4.00 –40°C to +85°C Pb-Free
3.08 –40°C to +85°C Pb-Free
2.93 –40°C to +85°C Pb-Free
2.63 –40°C to +85°C Pb-Free
4.63 –40°C to +85°C Pb-Free
4.38 –40°C to +85°C Pb-Free
4.00 –40°C to +85°C Pb-Free
3.08 –40°C to +85°C Pb-Free
2.93 –40°C to +85°C Pb-Free
2.63 –40°C to +85°C Pb-Free
MIC809LU MIC809LBC3 IL 4.63 –40°C to +85°C Standard
MIC809MU MIC809MBC3 IM 4.38 –40°C to +85°C Standard
MIC809JU MIC809JBC3 IJ 4.00 –40°C to +85°C Standard
MIC809TU MIC809TBC3 IT 3.08 –40°C to +85°C Standard
MIC809SU MIC809SBC3 IS 2.93 –40°C to +85°C Standard
MIC809RU MIC809RBC3 IR 2.63 –40°C to +85°C Standard
MIC810LU MIC810LBC3 JL 4.63 –40°C to +85°C Standard
MIC810MU MIC810MBC3 JM 4.38 –40°C to +85°C Standard
MIC810JU MIC810JBC3 JJ 4.00 –40°C to +85°C Standard
MIC810TU MIC810TBC3 JT 3.08 –40°C to +85°C Standard
MIC810SU MIC810SBC3 JS 2.93 –40°C to +85°C Standard
MIC810RU MIC810RBC3 JR 2.63 –40°C to +85°C Standard
MIC809LUY MIC809LYC3
MIC809MUY MIC809MYC3
MIC809JUY MIC809JYC3
MIC809TUY MIC809TYC3
MIC809SUY MIC809SYC3
MIC809RUY MIC809RYC3
MIC810LUY MIC810LYC3
MIC810MUY MIC810MYC3
MIC810JUY MIC810JYC3
MIC810TUY MIC810TYC3
MIC810SUY MIC810SYC3
MIC810RUY MIC810RYC3
Threshold Operating
Marking Voltage Temp. Range
MIC809LU MIC809LBC3 IL 4.63 –40°C to +85°C Standard
MIC809MU MIC809MBC3 IM 4.38 –40°C to +85°C Standard
MIC809JU MIC809JBC3 IJ 4.00 –40°C to +85°C Standard
MIC809TU MIC809TBC3 IT 3.08 –40°C to +85°C Standard
MIC809SU MIC809SBC3 IS 2.93 –40°C to +85°C Standard
MIC809RU MIC809RBC3 IR 2.63 –40°C to +85°C Standard
MIC810LU MIC810LBC3 JL 4.63 –40°C to +85°C Standard
MIC810MU MIC810MBC3 JM 4.38 –40°C to +85°C Standard
MIC810JU MIC810JBC3 JJ 4.00 –40°C to +85°C Standard
MIC810TU MIC810TBC3 JT 3.08 –40°C to +85°C Standard
MIC810SU MIC810SBC3 JS 2.93 –40°C to +85°C Standard
MIC810RU MIC810RBC3 JR 2.63 –40°C to +85°C Standard
4.63 –40°C to +85°C Pb-Free
4.38 –40°C to +85°C Pb-Free
4.00 –40°C to +85°C Pb-Free
3.08 –40°C to +85°C Pb-Free
2.93 –40°C to +85°C Pb-Free
2.63 –40°C to +85°C Pb-Free
4.63 –40°C to +85°C Pb-Free
4.38 –40°C to +85°C Pb-Free
4.00 –40°C to +85°C Pb-Free
3.08 –40°C to +85°C Pb-Free
2.93 –40°C to +85°C Pb-Free
2.63 –40°C to +85°C Pb-Free
MIC810 3-Lead SOT23
MIC810 3-Lead SC70
April 2005 3
M0450-041405
MIC809/810 Micrel
Absolute Maximum Ratings
(1)
Terminal Voltage (V
CC
)
...................................
–0.3V to 6.0V
Input Current (V
CC
)
.....................................................
20mA
Output Current (RESET, /RESET)
..............................
20mA
Lead Temperature (soldering, 10 sec.)
......................
300°C
Storage Temperature (T
S
)
..........................
–65°C to 150°C
Rate of Rise (V
CC
)
..................................................
100V/µs
ESD Rating
(3)
............................................
3
kV (SC70 Package
)
Operating Ratings
(2)
Operating Temperature Range
MIC809
.....................................................
–40°C to 85°C
MIC810
.....................................................
–40°C to 85°C
Power Dissipation (T
A
Power Dissipation (TA
Power Dissipation (T
= +70°C)
A = +70°C)
A
..............................
320mW
Electrical Characteristics
(4)
For typical values, V
CC
= 5V for MIC8_L/M/J, V
CC
= 3.3V for MIC8_S/T, V
CC
= 3V for MIC8_R; T
A
= 3V for MIC8_R; TA
= 3V for MIC8_R; T
= 25°C,
A = 25°C,
A
bold
values indicate –40°C
≤ T
A
≤ TA
≤ T
≤ +85°C; unless noted.
A ≤ +85°C; unless noted.
A
Symbol Parameter Condition Min Typ Max Units
V
CC
Operating Voltage Range T
A
Operating Voltage Range TA
Operating Voltage Range T
= 0°C to 70°C SOT-23 package
A = 0°C to 70°C SOT-23 package
A
1.4
5.5
V
T
A
TA
T
= –40°C to 85°C SOT-23 package
A = –40°C to 85°C SOT-23 package
A
1.6
5.5
V
T
A
TA
T
= –40°C to 85°C SC70 package
A = –40°C to 85°C SC70 package
A
1
5.5
V
I
CC
Supply Current MIC809L/M/J, MIC810L/M/J SOT-23 Package 9
15
µA
For SC-70 Package: MIC809L/M/J,
5
1
5
µA
MIC810L/M/J
V
CC
< 3.6V, MIC809R/S/T, MIC810R/S/T 6
10
µA
SOT-23 package
For SC-70 Package: V
CC
< 3.6V,
MIC809R/S/T, MIC810R/S/T
5
10
µA
V
TH
Reset Voltage Threshold MIC809L, MIC810L
4.50
4.63
4.75
V
MIC809M, MIC810M
4.25
4.38
4.50
V
MIC809J, MIC810J
3.89
4.00
4.10
V
MIC809T, MIC810T
3.00
3.08
3.15
V
MIC809S, MIC810S
2.85
2.93
3.00
V
MIC809R, MIC810R
2.55
2.63
2.70
V
t
RST
Reset Timeout Period
RST Reset Timeout Period
RST
140
240
560
ms
V
OH
/RESET Output Voltage I
SOURCE
= 800µA, MIC809L/M/J
V
CC
–1.5V
V
MIC809 I
SOURCE
= 500µA, MIC809R/S/T
0.8
×
V
CC
V
V
OL
/RESET Output Voltage MIC809 V
OL /RESET Output Voltage MIC809 V
OL
CC
= V
TH
min., I
SINK
= 3.2mA, MIC809L/M/J
0.4
V
V
CC
= V
TH
min., I
SINK
= 1.2mA, MIC809R/S/T
0.3
V
V
CC
> 1.4V, I
SINK
= 50µA, T
A
= 50µA, TA
= 50µA, T
= 0°C to +70°C
A = 0°C to +70°C
A
0.3
V
` For SC-70 Package: V
CC
= 1V, I
SINK
= 50
µ
A
0.3
V
T
A
TA
T
= –40°C to 85°C
A = –40°C to 85°C
A
V
CC
> 1.6V, I
SINK
= 50µA, T
A
= 50µA, TA
= 50µA, T
= –40° to +85°C
A = –40° to +85°C
A
0.3
V
V
OH
RESET Output Voltage MIC810 1.8V < V
CC
< V
TH
min., I
SOURCE
= 150µA
0.8
×
V
CC
V
V
OL
RESET Output Voltage MIC810 I
OL RESET Output Voltage MIC810 I
OL
SINK
= 3.2mA, MIC810L/M/J
0.4
V
I
SINK
= 1.2mA, MIC810R/S/T
0.3
V
Notes:
1.
Exceeding the absolute maximum rating may damage the device.
2. The device is not guaranteed to function outside its operating rating.
3.
Devices are ESD sensitive. Handling precautions recommended. Human body model, 1.5k in series with 100pF.
4. Specifi cation for packaged product only.
Symbol Parameter Condition Min Typ Max Units
Operating Voltage Range T
T
T
Supply Current MIC809L/M/J, MIC810L/M/J SOT-23 Package 9
V
SOT-23 package
MIC809R/S/T, MIC810R/S/T
Reset Voltage Threshold MIC809L, MIC810L
MIC809M, MIC810M
MIC809J, MIC810J
MIC809T, MIC810T
MIC809S, MIC810S
MIC809R, MIC810R
Reset Timeout Period
/RESET Output Voltage I
MIC809 I
/RESET Output Voltage MIC809 V
V
V
` For SC-70 Package: V
T
V
RESET Output Voltage MIC810 1.8V < V
RESET Output Voltage MIC810 I
I
Symbol Parameter Condition Min Typ Max Units
Operating Voltage Range T
T
T
Supply Current MIC809L/M/J, MIC810L/M/J SOT-23 Package 9
V
SOT-23 package
MIC809R/S/T, MIC810R/S/T
Reset Voltage Threshold MIC809L, MIC810L
MIC809M, MIC810M
MIC809J, MIC810J
MIC809T, MIC810T
MIC809S, MIC810S
MIC809R, MIC810R
Reset Timeout Period
/RESET Output Voltage I
MIC809 I
/RESET Output Voltage MIC809 V
V
V
` For SC-70 Package: V
T
V
RESET Output Voltage MIC810 1.8V < V
RESET Output Voltage MIC810 I
I
Symbol Parameter Condition Min Typ Max Units
Supply Current MIC809L/M/J, MIC810L/M/J SOT-23 Package 9
< 3.6V, MIC809R/S/T, MIC810R/S/T 6
= 3.2mA, MIC809L/M/J
= 1.2mA, MIC809R/S/T
= 0°C to +70°C
A
= –40° to +85°C
= 3.2mA, MIC810L/M/J
= 1.2mA, MIC810R/S/T
Symbol Parameter Condition Min Typ Max Units
5.5
Supply Current MIC809L/M/J, MIC810L/M/J SOT-23 Package 9
< 3.6V, MIC809R/S/T, MIC810R/S/T 6
4.63
4.38
4.00
3.08
2.93
2.63
240
V
V
= 3.2mA, MIC809L/M/J
= 1.2mA, MIC809R/S/T
= 0°C to +70°C
A
= –40° to +85°C
V
= 3.2mA, MIC810L/M/J
= 1.2mA, MIC810R/S/T
Symbol Parameter Condition Min Typ Max Units
5.5
V
V
V
Symbol Parameter Condition Min Typ Max Units
V
V
V
µA
µA
µA
V
V
V
V
V
V
ms
V
V
V
V
V
V
V
V
V
V
MIC809/810 Micrel
M0450-041405
4
April 2005
Functional Diagram
+
-
Reset
Threshold (V)
VCC (3) RESET (2)
RESET (MIC810)
GND (1)
RESET
GENERATOR
Timing Diagram
VCC VTH VTH
/RESET
tRST tRST
Reset Timing Diagram
April 2005 5
M0450-041405
MIC809/810 Micrel
Applications Information
Microprocessor Reset
The /RESET (or RESET) pin is asserted whenever V
CC
falls
below the reset threshold voltage. The /RESET pin remains
asserted for a period of 140ms after V
CC
has risen above
the reset 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
CC
as low as 1.4V (1V for SC-70 package).
V
CC
Transients
The MIC809/810 are relatively immune to negative-going V
CC
glitches below the reset threshold. Typically, a negative-going
transient 125mV below the reset threshold with a duration of
20µs or less (SC70 package) will not cause a reset.
Interfacing to Bidirectional Reset Pins
The MIC809/810 can interface with µPs with bidirectional
reset pins by connecting a 4.7kΩ resistor in series with the
MIC809/810 output and the µP reset pin.
/RESET Valid at Low Voltage
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 the /RESET to ground
is recommended. The resistor should be small enough to
pull-down any stray leakage currents and large enough not
to load the reset output. See Figure below.
VCC
RESET
µP
RESET
VCC
MIC809
VCC
100K
Reset Valid to V
CC
= 0V
MIC809/810 Micrel
M0450-041405
6
April 2005
Package Information
0.15 (0.006)
0.076 (0.0030)
0.41 (0.016)
0.13 (0.005)
3.05 (0.120)
2.67 (0.105) 8
0
0.445 (0.0175) TYP 3 PLACES
2.50 (0.098)
2.10 (0.083)
1.40 (0.055)
1.19 (0.047)
0.10 (0.004)
0.013 (0.0005)
1.15 (0.045)
0.76 (0.030)
DIMENSIONS:
MM (INCH)
2.36 (0.093)
2.28 (0.090)
C
L
C
L
3-lead SOT-23 (M3)
3-Lead SC-70 (C3)
MICREL, INC. 2180 FORTUNE DRIVE SAN JOSE, CA 95131 USA
TEL
+ 1 (408) 944-0800
FAX
+ 1 (408) 474-1000
WEB
http://www.micrel.com
The information furnished by Micrel in this data sheet is believed to be accurate and reliable. However, no responsibility is assumed by Micrel for its use.
Micrel reserves the right to change circuitry and specifi cations at any time without notifi cation to the customer.
Micrel Products are not designed or authorized for use as components in life support appliances, devices or systems where malfunction of a product can
reasonably be expected to result in personal injury. Life support devices or systems are devices or systems that (a) are intended for surgical implant into
the body or (b) support or sustain life, and whose failure to perform can be reasonably expected to result in a signifi cant injury to the user. A Purchaser’s
use or sale of Micrel Products for use in life support appliances, devices or systems is at Purchaser’s own risk and Purchaser agrees to fully indemnify
Micrel for any damages resulting from such use or sale.
© 2005 Micrel, Incorporated.
