MIC2785 Dual Supply Voltage Monitor with Manual Reset General Description Features The MIC2785 is a micropower voltage monitor that • No external components provides under-voltage monitoring and manual reset • Monitors input voltage for under-voltage condition capability in a tiny 1.2mm x 1.2mm MLF® package. The • Separate inputs for supply (VDD) and monitor (VIN) MIC2785 provides a monitored voltage input (VIN) separate • +1.5% VIN threshold voltage accuracy from the supply input (VDD). This insures that the reset • Valid /RST state with VIN down to 0.0V (/RST) output maintains a valid output state when the voltage being monitored ramps up or down. The device • Valid /RST state with VDD down to 1.20V also includes a manual reset input (/MR). The /RST output • Factory-programmed 1.62V reference is an active low push-pull output. • Manual reset input (/MR) The under-voltage detector compares the VIN pin voltage • Active low RESET (/RST) output against the factory-programmed threshold of 1.62V. The • Ultra-low input current – 5µA total (VIN and VDD) reset output is asserted any time the input voltage drops below the programmed threshold voltage. A reset can be • Rejects brief input transients generated at any time by asserting the manual reset input, • -25°C to 85°C operating temperature range /MR. This reset output will remain active until the release • RoHS lead-free compliant of /MR. The /MR input can also be used to daisy-chain the • Available in tiny 6-pin 1.2mm x 1.2mm Thin MLF® MIC2785 onto existing power monitoring circuitry or other package supervisors. Hysteresis is included to prevent chattering due to noise. The MIC2785 consumes a minimum of quiescent current, Applications only 5µA, 1.5µA from the main supply pin and 3.5µA from ® • Mobile phones the input pin. Offered in a tiny, space saving 6-pin MLF • PDAs (1.2mm x 1.2mm), package. (RoHS lead-free compliant). • GPS receivers Datasheets and support documentation can be found on Micrel’s web site at: www.micrel.com. ___________________________________________________________________________________________________________ Typical Application Memory or Microprocessor Voltage Monitor MicroLeadFrame and MLF are registered trademark of Amkor Technology, Inc. Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com March 2009 M9999-031709-A Micrel, Inc. MIC2785 Ordering Information(1) Part Number Typical Application Voltage Nominal Threshold Voltage Package 1.8V +10% 1.62V 6-Pin (1.2mm x 1.2mm) Thin MLF® MIC2785-16YFT Note: 1. Other voltage thresholds available. Contact Micrel for details. Pin Configuration 6-Pin (1.2mm x 1.2mm) Thin MLF® (FL) Pin Description Pin Number Pin Name 1 NC 2 VDD Analog (Input): Independent supply input for internal circuitry. 3 GND Ground. 4 VIN Analog (Input). Monitored input voltage. An under-voltage condition will trigger a reset sequence. 5 /MR Digital (Input): Asserting this pin low initiates an immediate and unconditional reset. Assuming VIN is above the threshold when /MR is released (returns high), the reset output will be de-asserted. /MR may be driven by a logic signal or a mechanical switch. /MR has an internal pull-up to VDD and may be left floating if unused. 6 /RST Digital (Output): Asserted low whenever the VIN pin voltage falls below the reference voltage or Manual Reset pin (/MR) is asserted. It will remain asserted until VIN voltage rises above the threshold voltage and the /MR pin is released. The maximum output voltage of the /RST pin is VIN. /RST is a push-pull output. March 2009 Pin Function Not Internally Connected. 2 M9999-031709-A Micrel, Inc. MIC2785 Absolute Maximum Ratings(1) Operating Ratings(2) Supply Voltage (VDD)........................................-0.3V to +6V Monitor Input (VIN) ............................................-0.3V to +6V Input Voltage (V/MR) ..........................................-0.3V to +6V /RST Current .............................................................±20mA Lead Temperature (soldering, 20sec.)....................... 260°C Junction Temperature (TJ) .........................-40°C to +125°C Storage Temperature (Ts) ..........................-65°C to +150°C ESD Rating(3) (Human Body Model) ............................. ±1.5kV Supply Voltage (VDD).................................... +1.5V to +5.5V Monitor Input (VIN) ......................................... –0.3V to + VDD Input Voltage (V/MR) ..................................... –0.3V to + 5.5V Ambient Temperature (TA) .......................... –40°C to +85°C Junction Thermal Resistance MLF® (θJA).....................................................140.7°C/W Electrical Characteristics(4) VDD = 3.1V; VIN = VDD = 3.1V TA = 25°C, bold values indicate –40°C< TA < +85°C, unless noted. Symbol Parameter Condition Min IDD Supply Current (VDD) VIN = VTH +1.6%, /MR & /RST open IIN Supply Current (VIN) VIN = VTH +1.6%, /MR & /RST open VTH Accuracy VHYST Hysteresis Voltage tPROP_TH Propagation Delay Typ Max 1.0 µA 3.5 -1.5 µA +1.5 1.5 VIN = VTH ±1 .5%, ±100mV 5 Units % % 25 µs VOL Output Voltage Low VIN ≤ VTH -1.5%, ISINK = 100µA, VDD > 1.2V VOH Output Voltage High VIN > VTH +1.5%, ISOURCE = 500µA VIH Input High Voltage VDD = 3.1V VIL Input Low Voltage VDD = 3.1V tPROP_MR Propagation Delay V/MR < (VIL –100mV) 0.5 tMIN Minimum Input Pulse Width V/MR < VIL reset occurs 33 ns IPU Internal Pull-up Current 100 nA 0.3 V 0.8 * VIN V 1.7 V /MR Input 0.4 V 25 µs 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. March 2009 3 M9999-031709-A Micrel, Inc. MIC2785 Timing Diagram March 2009 4 M9999-031709-A Micrel, Inc. MIC2785 Functional Diagram VREF. The VIN pin circuitry includes hysteresis to prevent /RST pin chattering due to noise. The VIN pin is relatively immune to very brief negative-going transients. Application Information Design and Product Advantages The MIC2785’s tiny 1.2mm x 1.2mm Thin MLF® package combined with no external components offers several advantages compared to conventional voltage supervisors. Tremendous savings are captured with decreased board size, reduced circuit complexity, and decreased bill of material (BOM) cost. Reset Output (/RST) The /RST pin is a complementary push-pull output, which source and sink current. The reset output is asserted any time the VIN pin voltage is less than the threshold voltage (VIN < VTH) or the /MR pin is asserted. The /RST pin responds very quickly to reset conditions, typically asserting within 5µs of VIN < VTH. The MIC2785 securely monitors the supply voltage of critical components like microcontrollers and microprocessors. With the MIC2785’s /RST pin connected to the μP’s reset pin, the processor will be properly reset at power on and during power-down and brown-out conditions. Power Supply Input (VDD) The VDD pin provides a stable input power for the internal circuitry. This insures that the reference circuitry and monitoring circuitry have a stable voltage over the entire operating voltage range. Supply bypassing is not required. However, bypassing may be valuable depending on the quality of the system voltage to which the VDD pin is connected. If bypassing is added, connect the capacitor(s) as closely as possible to the VDD pin. Place the lowest value capacitors closest to the VDD pin. Manual Reset Input (/MR) The /MR pin provides the ability to initiate a reset via external logic or a manual switch. This is in addition to the MIC2785’s automatic voltage monitoring function. Asserting the /MR input to a logic low causes an immediate and unconditional reset. Assuming the VIN pin voltage is within tolerance when /MR is released (returns high), the reset output will be de-asserted. /MR is internally pulled-up to VDD and may be left floating/ open if unused. Under-Voltage Detector Input (VIN) The largest portion of the monitoring circuitry is the VIN comparator. The VIN pin is connected to the noninverting terminal of the comparator. The internal reference is connected to the inverting terminal of the comparator. A reset is triggered when VIN falls below March 2009 5 M9999-031709-A Micrel, Inc. MIC2785 Package Information 6-Pin (1.2mm x 1.2mm) Thin MLF® (FL) 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. © 2009 Micrel, Incorporated. March 2009 6 M9999-031709-A