Micrel MIC809JU Microprocessor reset circuit Datasheet

MIC809/810
Microprocessor Reset Circuits
General Description
Features
The MIC809 and MIC810 are inexpensive microprocessor
supervisory circuits that monitor power supplies in microprocessor 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 VCC 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.
• Precision voltage monitor for 3V, 3.3V or 5V power supplies
• /RESET remains valid with VCC as low as 1.4V for SOT23 packaged part
• /RESET remains valid with VCC as low as 1V for SC70
packaged part
• Typically less than15µA supply current for SOT-23 packaged 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
Typical Application
Applications
•
•
•
•
•
Portable equipment
Intelligent instruments
Critical microprocessor power monitoring
Printers/computers
Controllers
VCC
VCC
VCC
MIC809
µP
RESET
RESET
Micrel, Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com
April 2005
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M0450-041405
MIC809/810
Micrel
Ordering Information
Part Number
3-lead SOT-23 Package3-lead SC-70 Package
Marking
Threshold
Voltage
Operating
Temp. Range
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
MIC809LUY
MIC809LYC3
IL
4.63
–40°C to +85°C
Pb-Free
MIC809MUY
MIC809MYC3
IM
4.38
–40°C to +85°C
Pb-Free
Pb-Free
MIC809JUY
MIC809JYC3
IJ
4.00
–40°C to +85°C
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
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..
Pin Configuration
GND 1
GND 1
MIC809
MIC810
3 VCC
3 VCC
RESET 2
RESET 2
MIC809 3-Lead SOT23
MIC809 3-Lead SC70
MIC810 3-Lead SOT23
MIC810 3-Lead SC70
Pin Description
Pin Number
MIC809
Pin Number
MIC810
Pin Name
Pin Function
IC Ground Pin.
1
1
GND
2
N/A
/RESET
/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.
N/A
2
RESET
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.
3
3
VCC
M0450-041405
Power Supply Input.
2
April 2005
MIC809/810
Micrel
Absolute Maximum Ratings(1)
Operating Ratings(2)
Terminal Voltage (VCC) ...................................–0.3V to 6.0V
Input Current (VCC)..................................................... 20mA
Output Current (RESET, /RESET) .............................. 20mA
Lead Temperature (soldering, 10 sec.) ...................... 300°C
Storage Temperature (TS) .......................... –65°C to 150°C
Rate of Rise (VCC) .................................................. 100V/µs
ESD Rating(3) ............................................ 3kV (SC70 Package)
Operating Temperature Range
MIC809 ..................................................... –40°C to 85°C
MIC810 ..................................................... –40°C to 85°C
Power Dissipation (TA = +70°C) .............................. 320mW
Electrical Characteristics(4)
For typical values, VCC = 5V for MIC8_L/M/J, VCC = 3.3V for MIC8_S/T, VCC = 3V for MIC8_R; TA = 25°C, bold values indicate –40°C
≤ TA ≤ +85°C; unless noted.
Symbol
Parameter
Condition
Min
VCC
Operating Voltage Range
TA = 0°C to 70°C
ICC
Supply Current
TA = –40°C to 85°C
tRST
1.4
5.5
V
1.6
5.5
V
5.5
V
MIC809L/M/J, MIC810L/M/J SOT-23 Package
1
9
15
µA
For SC-70 Package: MIC809L/M/J,
MIC810L/M/J
5
15
µA
VCC < 3.6V, MIC809R/S/T, MIC810R/S/T
SOT-23 package
6
10
µA
5
10
µA
SC70 package
/RESET Output Voltage
VOL
/RESET Output Voltage
VOL
4.50
4.63
4.75
V
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
140
240
560
ms
ISOURCE = 800µA, MIC809L/M/J
MIC809
MIC809
ISOURCE = 500µA, MIC809R/S/T
VCC–1.5V
0.8×VCC
RESET Output Voltage
MIC810
RESET Output Voltage
MIC810
V
V
0.4
V
VCC = VTH min., ISINK = 1.2mA, MIC809R/S/T
0.3
V
0.3
V
For SC-70 Package: VCC = 1V, ISINK = 50µA
A
TA = –40°C to 85°C
0.3
V
VCC = VTH min., ISINK = 3.2mA, MIC809L/M/J
VCC > 1.4V, ISINK = 50µA, TA = 0°C to +70°C
`
VOH
MIC809L, MIC810L
MIC809M, MIC810M
Reset Timeout Period
VOH
Units
SOT-23 package
TA = –40°C to 85°C
Reset Voltage Threshold
Max
SOT-23 package
For SC-70 Package: VCC < 3.6V,
MIC809R/S/T, MIC810R/S/T
VTH
Typ
VCC > 1.6V, ISINK = 50µA, TA = –40° to +85°C
1.8V < VCC < VTH min., ISOURCE = 150µA
ISINK = 3.2mA, MIC810L/M/J
0.3
0.8×VCC
ISINK = 1.2mA, MIC810R/S/T
V
V
0.4
V
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. Specification for packaged product only.
April 2005
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Micrel
Timing Diagram
VCC
VTH
VTH
tRST
tRST
/RESET
Reset Timing Diagram
Functional Diagram
+
VCC (3)
Reset
Threshold (V)
RESET
GENERATOR
-
RESET (2)
RESET (MIC810)
GND (1)
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April 2005
MIC809/810
Micrel
Applications Information
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 VCC 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.
Microprocessor Reset
The /RESET (or RESET) pin is asserted whenever VCC falls
below the reset threshold voltage. The /RESET pin remains
asserted for a period of 140ms after VCC 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
VCC as low as 1.4V (1V for SC-70 package).
VCC Transients
The MIC809/810 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
20µs or less (SC70 package) will not cause a reset.
VCC
VCC
VCC
MIC809
µP
RESET
RESET
100K
Reset Valid to VCC = 0V
April 2005
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M0450-041405
MIC809/810
Micrel
Package Information
1.40 (0.055) 2.50 (0.098)
1.19 (0.047) 2.10 (0.083)
CL
2.36 (0.093)
2.28 (0.090)
CL
DIMENSIONS
:
MM (INCH)
1.15 (0.045)
0.76 (0.030)
3.05 (0.120)
2.67 (0.105)
0.445 (0.0175) TYP 3 PLACES
8
0
0.10 (0.004)
0.013 (0.0005)
0.15 (0.006)
0.076 (0.0030)
0.41 (0.016)
0.13 (0.005)
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 specifications at any time without notification 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 significant 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.
M0450-041405
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April 2005
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