MIC2772 MICREL | Alldatasheet

Document overview

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Technical content

Features

  • Two independent voltage supervisors
  • Directly replaces discrete supervisors
  • Generates power-on reset pulses
  • De-bounced manual reset Inputs
  • Choice of voltage thresholds
  • 20, 140, or 1100ms reset timeouts
  • Reset output may be pulled above VCC
  • Rejects brief input transients
  • Ultra-small 2x2mm MLF package

Applications

  • Servers
  • Embedd ed Controllers
  • Tele communications Systems
  • Power Supply Sequencing
  • Hot-swap ping
  • Powe r supplies Typical Application MR1 MR2 GND2 RESET2 VCC2 VCC2 10k 10k RESET1 VCC1 VCC1 GND1 RESET VCC GND GND RESET VCC µP µP MIC2772 Typical Application Circuit April 2005 M9999-042005 (408) 955-1690

Ordering Information

Part Number Top Mark Supervisor 1 Supervisor 2 Standard Pb-Free Standard Pb-Free VTH (V) tRESET (ms) VTH (V) tRESET (ms) MIC2772-L2L3YML(2) UP0 4.63 20 4.63 140 MIC2772-M2M3YML (2) UP1 4.38 20 4.38 140 MIC2772-L3L3BML(1) MIC2772-L3L3YML(1) UP2 UP2 4.63 140 4.63 140 MIC2772-M3M3BML(1) MIC2772-M3M3YML(1) UP3 UP3 4.38 140 4.38 140 MIC2772-T3T3BML(1) MIC2772-T3T3YML(1) UP4 UP4 3.08 140 3.08 140 MIC2772-S3S3BML(1) MIC2772-S3S3YML(1) UP5 UP5 2.93 140 2.93 140 MIC2772-T2T3YML(2) UP6 3.08 20 3.08 140 MIC2772-S2S3YML(2) UP7 2.93 20 2.93 140 MIC2772-L3T3YML(2) UP8 4.63 140 3.08 140 MIC2772-M3S3YML(2) UP9 4.38 140 2.93 140 Note : 1. Available now. 2. Contact factory. Pin Configuration 1MR1 GND1 MR2 GND2

8 VCC1

8-lead 2mm X 2mm MLF(ML) April 2005 2 M9999-042605 (408) 955-1690

Pin Number Pin Name Pin Function /MR1 Digital Input; supervisor 1. Driving this pin low initiates an immediate and unconditional reset. If VCC1 is above the threshold when /MR1 is released (returns high), RESET1 will be de-asserted no less than tRESET1 later. /MR1 may be driven by a CMOS or TTL logic signal or a mechanical switch. De-bouncing is performed internally. /MR1 has an internal pull-up to VCC1; leave open if unused. 2 GND1 Ground return for supervisor 1. /MR2 Digital Input; supervisor 2. Driving this pin low initiates an immediate and unconditional reset. If VCC2 is above the threshold when /MR2 is released (returns high), the /RESET2 will be de-asserted no less than tRESET2 later. /MR2 may be driven by a CMOS or TTL logic signal or a mechanical switch. De- bouncing is performed internally. /MR2 has an internal pull-up to VCC2; leave open if unused. 4 GND2 Ground return for supervisor 2. /RESET2 Digital Output; open-drain; supervisor 2. Asserted low whenever VCC2 falls below the threshold voltage. It remains asserted for no less than tRESET2 and is de-asserted after VCC2 returns above the threshold. 6 VCC2 Analog Input. Power supply input for supervisor 2. /RESET1 Digital Output; open-drain; supervisor 1. Asserted low whenever VCC1 falls below the threshold voltage. It remains asserted for no less than tRESET1 and is de-asserted after VCC1 returns above the threshold. 8 VCC1 Analog Input. Power supply input for supervisor 1. April 2005 3 M9999-042605 (408) 955-1690

Absolute Maximum Ratings(1) Operating Ratings(2) Operating Temperature Range (TA).... -40°C to +85°C

Electrical Characteristics

For typical values, TA = 25°C, 2.5V ≤ VCCn ≤ 5.5V; values in bold are for 2.5V ≤ VCCn ≤ 5.5V, TMIN ≤ TA ≤ TMAX, unless otherwise noted. Symbol Parameter Condition Min Typ Max Units Power Supply IDD Supply Current /MR1 = /MR2 = /RESET1 = /RESET2 = open, VCC1 = VCC2 = 5.5V 10 30 µA /MR1 = /MR2 = /RESET1 = /RESET2 = open, VCC1 = VCC2 = 3.6V 10 20 µA /MR1 = /MR2 = /RESET1 = /RESET2 = open, VCCn = 0V, VCCm = 5.5V 5 15 µA /MR1 = /MR2 = /RESET1 = /RESET2 = open, VCCn = 0V, VCCm = 3.6V 5 10 µA /RESETn OUTPUTS L voltage code 4.5 4.63 4.75 V M voltage code 4.25 4.38 4.50 V S voltage code 2.85 2.93 3.00 V VTHn Reset-voltage threshold T voltage code 3.00 3.08 3.15 V timeout code = 2 20 44 ms timeout code = 3 140 320 tRESET Reset Pulse Width timeout code = 4 1100 2500 VCCn ≥ 4.25V, ISINK = 3.2mA 0.4 V VCCn ≥ 2.5V, ISINK = 1.2mA 0.3 V VOL /RESET Output Voltage Low VCCn ≥ 1V, ISINK = 50µA 0.3 V ILEAK Output leakage /RESET not asserted ±1 µA /MRn INPUTS VIH Input Voltage, High VTHn > 4.0V 2.3 V VTHn < 4.0V 0.7*V CC V VIL Input Voltage, Low VTHn > 4.0V 0.8 V VTHn < 4.0V 0.25* VCC V April 2005 4 M9999-042605 (408) 955-1690

Electrical Characteristics cont. Symbol Parameter Condition Min Typ Max Units tPROP /MR to /RESET Propagation Delay /MRn < VIL → /RESETn < VIL 0.5 µs tMIN Minimum Input Pulse Width Reset Occurs 10 µs tREJECT Widest Pulse Ignored No Reset Occurs 100 ns RPU Pull-up Resistance 10 20 30 kΩ Notes: 1. Exceeding the absolute maximum rating may damage the device. 2. The device is not guaranteed to function outside its operating rating. Timing Diagram VCCn /MRn /RESETn tRST tRST VTH MIC2772 Timing Diagram April 2005 5 M9999-042605 (408) 955-1690

Threshold (V) VCC1 (8) RESET1 (7)RESET GENERATOR MR1 (1) GND1 (2) GND2 (4) VCC Reset Threshold (V) VCC2 (6) RESET2 (5)RESET GENERATOR MR2 (3) VCC MIC2772 Block Diagram

Application Information

Reset Output, /RESET The /RESET pin is active l ow (open drain) pin. The /RESET pin i s asserted whenever VCC falls bel ow the reset threshold voltage or if /M R (manual reset) is forced low. The /RESET pin remains asserted for the duration of the thre shold timeou t period afte r VCC has risen above the reset threshold and/or /MR has returned high. Th e reset fun ction ensures th e microprocessor is properly reset and power up i n a known condition after a po wer failure. /RESET will remain valid with VCC as low as 1.0V. The /RESET output i s a simple open-drain N- channel MOSFET structure. A pull-up resi stor must be used to pull this o utput to some voltage. For most appli cations, this voltage will be the same power supply that sup plies VCC to MI C2772. It is possible however to tie this re sistor to some othe r voltage. This will allow the MIC2772 to monitor one voltage while level-shifting the /RESET output to some other voltage. The pull-up voltage mu st be limited to 6.0V or less (absolute maximum) to avoid damage to the MIC2772. The resistor must be small enough to supply current to the inp uts and leakage paths that are driven by the /RESET output. Manual Reset Input, /MR The ability to initiate a reset via external logic or a manual switch is provided in addi tion to the MIC2772’s automatic supervisory functions. Drivin g the /MR inpu t to a logic l ow cau ses a n immediate and unconditional reset to occu r. Assuming VCC i s within tolerance when /MR is released (returns high), the /RESET output will be de-asserted no less than tRESET later. /MR may b e driven by a CMOS or T TL logic sig nal, or a me chanical swit ch. Typically, a momentary push -button switch i s co nnected su ch that /MR is sho rted to grou nd wh en the switch contacts c lose. Sw itch de-bouncing is pe rformed internally; th e switch ma y be conn ected directly between /M R and GND. /MR h as an i nternal 20 kΩ pull-up re sistor (typical) t o VCC an d may be left open if unused. April 2005 6 M9999-042605 (408) 955-1690

(408) 955-1690

(408) 955-1690

Package Information

8-Pin 2mm X 2mm MLF (ML) 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. How ever, 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 authoriz ed for use as components in life su pport appliances, devices or sy stems where malf unction 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 bo dy or (b) support or sustain life, and whose failure to p erform can be reasonably expected to resul t in a significant injury to the user. A Purchaser’s use or sale of M icrel Products for use in life support appliances, d evices or sy stems is a Pu rchaser’s own risk and Purchaser agrees to fully indemnify Micrel for any damages resulting from such use or sale. © 2005 Micrel, Incorporated.