MIC812JUY TR - Micrel - Datasheet.Directory

MIC811/812

Microprocessor Reset Ci r cui ts

General Descr i ption

The MIC811 and MIC812 are inexpensive microprocessor

supervisory circuits that monitor power supplies in

microprocessor based systems.

The function of this device is to assert a reset if either the

power supply drops below a designated reset threshold

level or /MR is forced low. Several different reset threshold

levels are available to accommodate 3V, 3.3V or 5V

powered systems.

The MIC811 has an active low /RESET output, while the

MIC812 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 designed reset

threshold level. Having a push-pull output stage, the

MIC811/812 does not require a pull-up resistor at the

output. The MIC811/812 comes in a 4-pin SOT-143

package.

If a microprocessor voltage supervisor with an open-drain

output stage is needed, see MIC6315.

Datasheets and support documentation are available on

Micrel’s web site at: www.micrel.com.

Features

• Precision voltage monitor for 3V, 3.3V or 5V power

supplies

• /RESET remains val i d with VCC as low as 1V

• 5μA typical supply current

• 140ms minimum re set pulse width available

• Manual reset input

• Available in 4-pin S O T-143 package

Applications

• Portable equipment

• Intelligent instruments

• Critical microprocessor power monitoring

• Printers/computers

• Controllers

Typical Applicatio n

Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com

September 9, 2014 Revision 2.0

Micrel, Inc.

MIC811/812

Ordering I nfor m ati on

Part Number

Pb-Free Marking(1) Threshold Voltage Operating Temp. Range Package

MIC811LUY KL 4.63 –40°C to +85°C 4-pin SOT-143

MIC811MUY KM 4.38 –40°C to +85°C 4-pin SOT-143

MIC811JUY KJ 4.00 –40°C to +85°C 4-pin SOT-143

MIC811TUY KT 3.08 –40°C to +85°C 4-pin SOT-143

MIC811SUY KS 2.93 –40°C to +85°C 4-pin SOT-143

MIC811RUY KR 2.63 –40°C to +85°C 4-pin SOT-143

MIC812LUY LL 4.63 –40°C to +85°C 4-pin SOT-143

MIC812MUY LM 4.38 –40°C to +85°C 4-pin SOT-143

MIC812JUY LJ 4.00 –40°C to +85°C 4-pin SOT-143

MIC812TUY LT 3.08 –40°C to +85°C 4-pin SOT-143

MIC812SUY LS 2.93 –40°C to +85°C 4-pin SOT-143

MIC812RUY LR 2.63 –40°C to +85°C 4-pin SOT-143

Note:

1. “_” underbar symbol not to scale

Pin Configuration

MIC811 4-Pin SOT-143 (U)

MIC812 4-Pin SOT-143 (U)

Pin Description

MIC811

MIC812

Pin Name

1 1 GND IC Ground Pin.

2 N/A /RESET /RESET goes low if VCC falls below the reset threshold and remains asserted

for one reset timeout perio d ( 140ms min.) after VCC exceeds the reset

threshold.

N/A 2 RESET RESET goes high if VCC falls below the reset threshold and rem ains asserted

for one reset timeout perio d ( 140ms mi n.) aft er VCC exc eeds the reset

threshold.

3 3 /MR

Manual Reset Input. A logic low on /MR will force a reset. The reset will

remain assert ed as long as /MR is held low and for one reset tim eout period

(140ms min.) after /MR goes high. This input c an be shorted to gr ound via a

switch or driven from CMOS or TTL logic. Float if unused.

4 4 VCC Power Supply Input.

September 9, 2014 2 Revision 2.0

Micrel, Inc.

MIC811/812

Absolute Ma xi mu m Ratings(2)

Terminal Voltage (VCC) ................................ -0.3V to +6.0V

Input Current (VCC, /MR). ........................................... 20mA

Output Current (/RESET, RESET) .............................. 20mA

Lead Temperat ure (soldering, 10s) ............................ 300°C

Storage Temperature (Ts) ............................... 5°C to 150°C

Rate of Rise (VCC) ................................................. 100V/µs

ESD Rating(4) .................................................................. 3kV

Operating Ratings(3)

Operating Temperature Ra nge

MIC811 ................................................. –40°C to +85°C

MIC812 ................................................. –40°C to +85°C

Power Dissipat i on (TA = +70°C ) ............................... 320mW

Thermal Resistance

SOT-143 (θJA) .................................................. 265°C/W

Electric al Characteristics(5)

For typical values, VCC = 5V for M IC8_L/M/J, VCC = 3.3V for MIC8_S/T, VCC = 3V for MIC8_R; TA = 25°C, bold values in dicate –

40°C to ≤ TA ≤ +85°C; unl es s noted.

Symbol

Parameter

Condition

Min

Typ

Max

Units

VCC Operating Voltage Range T

= –40°C to 85°C 1 5.5 V

IVCC Supply Current

MIC811L/M/J, MIC812L/M/J: VCC = 5.0V,

no load 5 15 µA

MIC811S/T , MIC812S/T: VCC = 3.3V, no

load 5 10 µA

MIC811R, MIC812R: VCC = 3.0V, no load 5 10 µA

VTH Reset Voltage T hreshold

MIC811L, MI C 812L 4.50 4.63 4.75 V

MIC811M, MIC812M 4.25 4.38 4.50 V

MIC811J, MIC812J 3.89 4.00 4.10 V

MIC811T, M IC812T 3.00 3.08 3.15 V

MIC811S, MIC812S

2.85

2.93

3.00

MIC811R, MIC812R

2.55

2.63

2.70

tRST Reset Tim eout Period 140 240 560 ms

VOH /RESET Output Voltage ISOURCE = 800µA , MIC811L/M/J VCC–1.5V V

ISOURCE = 500µA, MIC811R/S/T 0.8xVCC V

VOL /RESET Output V ol tage

VCC = VTH min., ISINK = 3.2mA, MIC811L/M/J 0.4 V

VCC = VTH min., ISINK = 1.2mA,

MIC811R/S/T 0.3 V

VCC >1V, I

SINK

= 50µA, T

= –40°C to +85°C 0.3 V

VOH RESET Output Voltage 1.8V <VCC <V

min., I

SOURCE

= 150µA 0.8xVCC V

VOL RESET Output Voltage ISINK = 3.2mA, MIC812L/M/J 0.4 V

SINK

= 1.2mA, MIC812R/S/T 0.3 V

Notes:

2. Exceeding the absolute maximum ratings may damage the device.

3. The device is not guaranteed to function outside its operating ratings.

4. Devices are ESD sensitive. Handling precautions are recommended. Human body model, 1.5kΩ in series with 100pF.

5. Specification for packaged product only

September 9, 2014 3 Revision 2.0

Micrel, Inc.

MIC811/812

Electric al Characteristics (Cont inued)(5)

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 to

≤ TA ≤ +85°C; unless noted.

Symbol Parameter Condition Min Typ Max Units

/MR Minimum Pulse Width 10 µs

/MR to Reset Delay 0.5 µs

VIH /MR Input T hreshold VCC > VTH max., MIC81_L/M/J 2.3 V

MIC81_R/S/T 0.7xVCC V

VIL /MR Input Thr eshold VCC > VTH max., MIC81-L/M/J 0.8 V

MIC81_R/S/T

0.25xVCC

/MR Pull-Up Resist ance 10 20 30 kΩ

/MR Glitch Immunity 100 ns

Timing Diagram

Reset Timing Diagram

Functional Diagram

September 9, 2014 4 Revision 2.0

Micrel, Inc.

MIC811/812

Application Inform ation

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 that 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 1V.

VCC Transients

The MIC811/812 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 will not cause a

reset.

Interfacing to Bidirectional Reset Pins

The MIC811/812 c an interface with µPs with bidirectional

reset pins by connecting a 4.7kΩ resistor in series with

the MIC811/812 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 size of the resistor should

be large enough not to load the output excessively and

small enough t o pul l -down any stray leakage currents.

Reset Valid to VCC = 0V

September 9, 2014 5 Revision 2.0

Micrel, Inc.

MIC811/812

Package I nformation

4-Pin SOT-143 (U)

September 9, 2014 6 Revision 2.0

Micrel, Inc.

MIC811/812

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

Micrel, Inc. is a leading global manufac turer of IC solutions for the worldwide high performance linear and power, LAN, and timing &

communications markets. The Compan y’s products incl ude advance d mixed-signal, analog & power semiconductors; high-

performance communicat ion, clock man agement, MEMs-based clock oscillators & crystal-less clock generators, Ethernet switches,

and physical layer transceiver ICs. C om pany customers i nclude leadi ng manufactur ers of enterprise, consumer, industrial, mobile,

telecommunications, automotive, and com puter products. Corpor ation headquarters and state-of-the-art wafer fabrication facilities are

located in San Jose, CA, with regional sales and support off i c es and advanced technology design centers s i tuated throu ghout the

Americas, Europe, and Asi a. Additionally, the Company maintai ns an extensive n etwork of dist ributors and re ps worldwide.

Micrel makes no representations or warr anties with respect to the accur acy or completeness of the inf ormation furnished in this

datasheet. This informat i on is not intended as a warranty and Micrel does not assume responsibilit y for its use. Micrel reserves the

right to change circuitry, specifications and descriptions at any time without notice. No license, whether expr es s, implied, arising by

estoppel or otherwise, to any intellectual pr operty rights i s granted by thi s document. E xcept as provided in Micrel’s terms and

conditions of sale for such pr oducts, Micrel assumes no lia bil ity whatsoever, and Micrel disclaims any express or implied warranty

relating to the sale and/or use of Micrel pro duc ts including liability or warranties relating to fitness for a particul ar purpose,

merchantabi l ity, or infr ingement of any patent, cop yright, or other intellectual pr operty right.

Micrel Products are not designed or aut horized for us e as components in life support appliances, dev i c es or systems where

malfunction of a product can reasonably be expected to result in personal injury. Life su pport devices or systems are devices or

systems that (a) are intende d for surgical implant into the body or (b) support or sustain life, and whose failure to perform can be

reasonabl y e xpected to result in a significant injury to the user. A Purchaser’s use or sale of Micrel Produ c ts for use in life support

appliances, devices or s ystems is a Purchaser’s own risk and Purchaser agr ees to fully i ndemnify Micrel for any damages r esulting

from such use or sale.”

September 9, 2014 7 Revision 2.0

Mouser Electronics

Authorized Distributor

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