MIC2772 Dual Voltage Supervisor General Description Features The MIC2772 is a dual power supply supervisor that provides under-voltage monitoring and power-on reset generation. It may replace two discrete voltage supervisors such as MIC1810, MIC1815, MIC809, MIC811, MIC6315, etc. The two voltage supervisors are completely independent. Each functional block features an under-voltage detector, a delay-generator, and a de-bounced manual reset input. A wide choice of voltage thresholds is available. The reset output is asserted at power-on and any time the input voltage drops below the reference voltage. It remains asserted for the chosen timeout period after the input rises back above the threshold. Reset timeouts of 20, 140, and 1100ms (minimum) are available. A reset can be generated at any time by asserting the manual reset input, /MR. This input is internally de-bounced, and the reset output will remain active for the timeout period after the release of /MR. The /MR input can also be used to daisy-chain one or more of the MIC2772’s supervisors onto existing power monitoring circuitry or other supervisors. The tiny 2x2mm MLF package has a footprint smaller than that of a single SOT23 voltage supervisor. Data sheets and support documentation can be found on Micrel’s web site at www.micrel.com. • • • • • • • • • 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 Embedded Controllers Telecommunications Systems Power Supply Sequencing Hot-swapping Power supplies ____________________________________________________________________________________________________ Typical Application VCC1 10k MR1 VCC1 RESET1 GND1 VCC RESET GND µP VCC RESET GND µP VCC2 10k MR2 VCC2 RESET2 GND2 MIC2772 Typical Application Circuit April 2005 M9999-042005 (408) 955-1690 Micrel MIC2772 Ordering Information Part Number Standard MIC2772-L3L3BML(1) MIC2772-M3M3BML(1) MIC2772-T3T3BML(1) MIC2772-S3S3BML(1) Top Mark Standard Pb-Free Pb-Free MIC2772-L2L3YML(2) MIC2772-M2M3YML (2) MIC2772-L3L3YML(1) MIC2772-M3M3YML(1) MIC2772-T3T3YML(1) MIC2772-S3S3YML(1) MIC2772-T2T3YML(2) MIC2772-S2S3YML(2) MIC2772-L3T3YML(2) MIC2772-M3S3YML(2) UP0 UP1 UP2 UP3 UP4 UP5 UP6 UP7 UP8 UP9 UP2 UP3 UP4 UP5 Supervisor 1 tRESET VTH (V) (ms) 4.63 20 4.38 20 4.63 140 4.38 140 3.08 140 2.93 140 3.08 20 2.93 20 4.63 140 4.38 140 Supervisor 2 tRESET VTH (V) (ms) 4.63 140 4.38 140 4.63 140 4.38 140 3.08 140 2.93 140 3.08 140 2.93 140 3.08 140 2.93 140 Note: 1. Available now. 2. Contact factory. Pin Configuration MR1 1 8 VCC1 GND1 2 7 RESET1 MR2 3 6 VCC2 GND2 4 5 RESET2 8-lead 2mm X 2mm MLF(ML) April 2005 2 M9999-042605 (408) 955-1690 Micrel MIC2772 Pin Description Pin Number April 2005 Pin Name 1 /MR1 2 GND1 3 /MR2 4 GND2 5 /RESET2 6 VCC2 7 /RESET1 8 VCC1 Pin Function 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. Ground return for supervisor 1. 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. Debouncing is performed internally. /MR2 has an internal pull-up to VCC2; leave open if unused. Ground return for supervisor 2. 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. Analog Input. Power supply input for supervisor 2. 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. Analog Input. Power supply input for supervisor 1. 3 M9999-042605 (408) 955-1690 Micrel MIC2772 Absolute Maximum Ratings(1) Operating Ratings(2) Supply Voltage, VCC ...............................-0.3V to 6.0V Input Voltage, /MR ....................... -0.3V to VCC + 0.3V Input Voltage, /RESET ..........................-0.3V to 6.0V Input Current (VCC, /MR) ................................. 20mA Output Current (/RESET) ................................ 20mA Storage Temperature....................... -65°C to +150°C ESD Rating (Note 3) .............................................3kV Supply Voltage...........................................1V to 5.5V Input Voltage (/MR )..................................... 0 to 5.5V Input Voltage (/RESET ) ............................ 0 to +5.5V Operating Temperature Range (TA).... -40°C to +85°C Lead Temperature – Soldering, 10s .................300°C Package Thermal Resistance (θJA)................ 93°C/W 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 /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 Power Supply IDD Supply Current /RESETn OUTPUTS VTHn tRESET Reset-voltage threshold Reset Pulse Width 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 T voltage code 3.00 3.08 3.15 V timeout code = 2 20 44 ms VOL ILEAK /RESET Output Voltage Low Output leakage timeout code = 3 140 320 timeout code = 4 1100 2500 VCCn ≥ 4.25V, ISINK = 3.2mA 0.4 V VCCn ≥ 2.5V, ISINK = 1.2mA 0.3 V VCCn ≥ 1V, ISINK = 50µA 0.3 V /RESET not asserted ±1 µA /MRn INPUTS VIH VIL Input Voltage, High Input Voltage, Low April 2005 VTHn > 4.0V 2.3 V VTHn < 4.0V 0.7*V CC V VTHn > 4.0V 0.8 V VTHn < 4.0V 0.25* VCC V 4 M9999-042605 (408) 955-1690 Micrel MIC2772 Electrical Characteristics cont. Symbol Parameter Condition tPROP /MR to /RESET Propagation Delay /MRn < VIL → /RESETn < VIL tMIN Minimum Input Pulse Width Reset Occurs tREJECT Widest Pulse Ignored No Reset Occurs RPU Min Typ Max 0.5 µs 10 10 Pull-up Resistance Units µs 100 ns 20 kΩ 30 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. Timing Diagram VCCn VTH /MRn /RESETn tRST tRST MIC2772 Timing Diagram April 2005 5 M9999-042605 (408) 955-1690 Micrel MIC2772 Functional Block Diagram VCC MR1 (1) RESET GENERATOR RESET1 (7) RESET GENERATOR RESET2 (5) + VCC1 (8) Reset Threshold (V) GND1 (2) VCC MR2 (3) + VCC2 (6) Reset Threshold (V) GND2 (4) MIC2772 Block Diagram Application Information Reset Output, /RESET The /RESET pin is active low (open drain) pin. The /RESET pin is asserted whenever VCC falls below the reset threshold voltage or if /MR (manual reset) is forced low. The /RESET pin remains asserted for the duration of the threshold timeout period after VCC has risen above the reset threshold and/or /MR has returned high. The reset function ensures the microprocessor is properly reset and power up in a known condition after a power failure. /RESET will remain valid with VCC as low as 1.0V. The /RESET output is a simple open-drain Nchannel MOSFET structure. A pull-up resistor must be used to pull this output to some voltage. For most applications, this voltage will be the same power supply that supplies VCC to MIC2772. It is possible however to tie this resistor to some other voltage. This will allow the MIC2772 to monitor one voltage while level-shifting the /RESET output to some other voltage. The pull-up voltage must 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 inputs and leakage paths that are driven by the /RESET output. April 2005 Manual Reset Input, /MR The ability to initiate a reset via external logic or a manual switch is provided in addition to the MIC2772’s automatic supervisory functions. Driving the /MR input to a logic low causes an immediate and unconditional reset to occur. Assuming VCC is within tolerance when /MR is released (returns high), the /RESET output will be de-asserted no less than tRESET later. /MR may be driven by a CMOS or TTL logic signal, or a mechanical switch. Typically, a momentary push-button switch is connected such that /MR is shorted to ground when the switch contacts close. Switch de-bouncing is performed internally; the switch may be connected directly between /MR and GND. /MR has an internal 20kΩ pull-up resistor (typical) to VCC and may be left open if unused. 6 M9999-042605 (408) 955-1690 Micrel MIC2772 Motorola 68HC11 family is one example. Because the MIC2772’s output is active-low, open-drain, it can be connected directly to the processor’s reset pin with only the pull-up resistor normally required. MAX. TRANSIENT DURATION (µs) Transients on VCC The MIC2772 is inherently immune to very short “glitches” on VCC. In the case of very brief transients, VCC may drop below the reset-voltage threshold without triggering a reset. As shown in the graph, the MIC2772 is relatively immune to transients with typical duration of 25us. The lines on the graph represent the typical allowable transient duration for a given amount of threshold overdrive that will not generate a reset. The data was taken by adding negative-going square-wave pulse to a DC input voltage set at 0.5V above actual measured threshold for the part being characterized. Figure 1 shows the graph for the MIC2772[UP3] and Figure 2 shows the graph for the MIC2772[UP5] 35 MIC2772 Replaces Single Supervisor The table below lists common single voltage supervisors that can be considered for replacement by MIC2772. Typical Transient Response P/N Suffix Supervisor #1 Supervisor #2 L2L3 MIC6315-46D2 MIC1810-5, MIC6315-46D3, MIC809L, MIC811L M2M3 MIC6315-44D2 MIC1810-10, MIC6315-44D3, MIC809M, MIC811M L3L3 MIC1810-5, MIC6315-46D3, MIC809L, MIC811L MIC1810-5, MIC6315-46D3, MIC809L, MIC811L M3M3 MIC1810-10, MIC6315-44D3, MIC809M, MIC811M MIC1810-10, MIC6315-44D3, MIC809M, MIC811M T3T3 MIC6315-31D3, MIC809T, MIC811T MIC6315-31D3, MIC809T, MIC811T S3S3 MIC1815-10, MIC6315-29D3, MIC809S, MIC811S MIC1815-10, MIC6315-29D3, MIC809S, MIC811S T2T3 MIC6315-31D2 MIC6315-31D3, MIC809T, MIC811T S2S3 MIC6315-29D2 MIC1815-10, MIC6315-29D3, MIC809S, MIC811S L3T3 MIC1810-5, MIC6315-46D3, MIC809L, MIC811L MIC6315-31D3, MIC809T, MIC811T M3S3 MIC1810-10, MIC6315-44D3, MIC809M, MIC811M MIC1815-10, MIC6315-29D3, MIC809S, MIC811S 30 25 20 15 10 5 0 VTH = 4.393V 0 200 400 600 800 1000 RESET COMP. OVERDRIVE VTH - VCC (mV) MAX. TRANSIENT DURATION (µs) Figure 1 40 Typical Transient Response 35 30 25 20 15 10 5 VTH = 2.933V 0 0 200 400 600 800 1000 RESET COMP. OVERDRIVE VTH - VCC (mV) Figure 2 Interfacing to Processors with Bi-directional Reset Pins Some microprocessors have reset signal pins that are bi-directional, rather than input only. The April 2005 7 M9999-042605 (408) 955-1690 Micrel April 2005 MIC2772 8 M9999-042605 (408) 955-1690 Micrel MIC2772 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. 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 a Purchaser’s own risk and Purchaser agrees to fully indemnify Micrel for any damages resulting from such use or sale. © 2005 Micrel, Incorporated. April 2005 9 M9999-042605 (408) 955-1690