MIC2786/7/8/9 Evaluation Board Push-Button Reset IC General Description Getting Started The MIC2786/7/8/9 are low-current, ultra-small, push- 1. VIN Supplies button reset supervisors with long set-up delays. All the Connect a supply to the VIN and GND terminals, paying devices feature two manual reset inputs and two reset careful attention to the polarity and the supply range outputs. The devices initiate a reset for the reset timeout (1.5V VIN 5.5V). An ammeter may be placed period when the /MR0 and /MR1 inputs are asserted low between the input supply and the VIN terminal to the for a period longer than the set-up delay. evaluation board. Ensure that the supply voltage is In addition, the MIC2786 and MIC2787 feature an monitored at the VIN terminal. The ammeter can reduce integrated supply voltage monitor. Reset will be the voltage supplied to the input. asserted for the reset timeout delay once the supply 2. Connect PDY Pin (J5) voltage increases above the rising threshold voltage. Connect the programmable delay input (PDY) pin The MIC2786 and MIC2788 feature integrated pull-up according to desired set-up delay. Leave PDY pin open resistors on the /MR0 and /MR1 inputs, while the for setup-delay of 2s, connect to GND for set-up delay of MIC2787 and MIC2789 require external pull-up 4s or connect to VIN for set-up delay of 6s. resistors. The PDY input pin selects between a 2s, 4s, 3. Monitor Inputs and Outputs or 6s set-up period. Factory-programmed reset timeout Monitor the inputs (/MR0 and /MR1) and outputs (/RST periods of 140ms (minimum) and 240ms (minimum) are and RSTP) with an oscilloscope. available. 4. Turn on the Power The MIC2788-XYMT EV Evaluation Board comes with the MIC2788-XYMT (t = 140ms) installed, but it can Turn on the power supply. Observe that /MR0, /MR1 RESET also be used to evaluate the MIC2786, MIC2787 and and /RST are pulled up to VIN while RSTP remains at MIC2789. Contact Micrel or an authorized distributor for 0V. samples and simply replace the chip on board, as these 5. Press Push-Buttons devices are all pin-to-pin compatible. Press push-button inputs /MR0 and /MR1 and observe For the MIC2787 and MIC2789, positions R1 and R2 will /RST and RSTP outputs. Keeping the push-button need to be populated with 100k resistors. inputs asserted low for the programmed setup delay Datasheets and support documentation can be found on time initiates one reset output pulse for the reset timeout Micrels web site at: www.micrel.com. delay period. Requirements Ordering Information The MIC2788 Evaluation Board requires only a single power supply that is capable of delivering greater than Part Number Description 1mA at a voltage range of 1.5V to 5.5V. An oscilloscope MIC2788-XYMT EV MIC2788 Evaluation Board can be used to view and measure the inputs and outputs. Precautions There is no reverse input protection on this board. While connecting supplies and signals ensure that correct polarities are observed. The maximum operating VIN is rated at 5.5V. MLF and MicroLeadFrame are trademarks of Amkor Technology, Inc. Micrel Inc. 2180 Fortune Drive San Jose, CA 95131 USA tel +1 (408) 944-0800 fax + 1 (408) 474-1000 Micrel, Inc. MIC2786/7/8/9 Evaluation Board Evaluation Board Features See the MIC2788/MIC2789 datasheet for detailed explanations of these functions. For detailed operation of the MIC2786/MIC2787 see the MIC2786/MIC2787 datasheet. Programmable Delay Pin (PDY) Use Table 1 to program the PDY pin for desired set- up delay time. PDY Configuration (J5) t SETUP OPEN 2s GND 4s V 6s IN Figure 2. Manual Reset Function for 4.0s Set-Up Delay (PDY = GND) Table 1. PDY Configuration for Desired Set-Up Delay Figures 1, 2 and 3 illustrate manual reset function for set-up delays as per PDY pin connection. Figure 3. Manual Reset Function for 6.0s Set-Up Delay (PDY = VIN) Figure 1. Manual Reset Function for 2.0s Set-Up Delay Dual Manual Reset Inputs (/MR0, /MR1) (PDY = OPEN) The manual reset inputs can be operated manually using the push-buttons provided or by connecting a function generator. Test points J1 J4 are provided on the manual reset inputs for connecting to a function generator and monitoring on an oscilloscope simultaneously. Reset Outputs (/RST, RSTP) The /RST output has a 100k pull-up resistor to VIN. Test-point J7 is provided for monitoring the /RST signal on an oscilloscope. The RSTP output can be monitored directly by an oscilloscope connected to the test-point J6. M9999-052412 2 May 2012