DC1099A Analog Devices

QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 1099 PUSH BUTTON ON/OFF CONTROLLER WITH BATTERY AND SUPPLY MONITORING LTC2953CDD-1 DESCRIPTION Demonstration circuit 1099 features the LTC2953, a The adjustable supply monitor input is compared push button On/Off controller that manages system against an accurate internal 0.5V reference. The reset power via a push button interface. An enable output output remains low until the supply monitor input has toggles system power while an interrupt output pro- been in compliance for 200ms. vides debounced push button status. The interrupt The DC1099 accepts voltages of 2.7V to 27V over the output can be used in menu driven applications to operating range of the LTC2953 input voltage. The request a system power down. LTC2953 draws only 12uA of current. Reverse polar- The length of time that the push button must be held ity protection is provided with RPP and CPP on the low for a power down is configurable with an external DC1099. Two versions of the part accommodate ei- capacitor. The LTC2953 allows a user to force an ther positive or negative enable polarities. For the immediate power down by tying /INT with /KILL and a DC1099, the LTC2953-1 with Enable active high is push button turn off. shown. The LTC2953 also features input and output supply On the DC1099, an LT3010 is used to demonstrate a monitors. An uncommitted power fail comparator supply with its shutdown pin driven by the enable of provides real time input monitor threshold informa- the LTC2953. tion, while a de-glitched under voltage lockout com- Design files for this circuit board are available. Call parator gracefully initiates a system power down. the LTC factory. The under voltage lockout comparator prevents from LTC is a trademark of Linear Technology Corporation powering from a bad battery. Table 1. Typical Performance Summary (T = 25C) A PARAMETER CONDITION VALUE Input Voltage Range V Operating Range (Note 1) 2.7V to 27V IN DC/DC Out 2P6V DC/DC LT3010 Enabled through Push Button 2.6V Power Fail Input Voltage PFI VIN Threshold, Resistor Divider (R14 + R13) and R12 3.00V UVLO Monitor Input Voltage VIN Threshold, Resistor Divider R14 and (R13 + R12) 2.65V Voltage Monitor VM Voltage Threshold to VM (2P6V), Resistor Divider R3 and R2 2.33V Monitor Pins Threshold Voltage /PFI, VM, UVLO 500mV UVLO Input Hysteresis UVLO Pin (Note 1) 30mV Turn ON Debounce Time Push Button Turn On 32ms JP2 Set to OPEN, Push Button Turn Off 32ms Turn OFF Debounce Time JP2 Set to CAP to Connect 0.47uF to PDT Pin (Note 2) 32ms + 3008ms Note 1: The resistor divider at UVLO sets 2.7V above the UVLO threshold. Supply must first ramp up above 3.0V to exceed the UVLO Input Hysteresis for operation between 2.7V to 3.0V. Note 2: 0.47uF * (6.4 seconds / uF) = 3.008 seconds 1 QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 1099 PUSH BUTTON ON/OFF CONTROLLER WITH BATTERY AND SUPPLY MONITORING QUICK START PROCEDURE Demonstration circuit 1099 is easy to set up to 5. Again, push down on Push Button SW1 for a Turn evaluate the performance of the LTC2953. Refer to On. Figure 1 for proper measurement equipment setup 6. Ramp down supply below 3.0V and no lower than and follow the procedure below. 2.7V. /PFO LED will turn on. 1. Place jumpers in the following positions: 7. Ramp down supply below 2.65V. /INT LED will JP1 UNTIE momentarily turn on, then turn off along with 2P6V LED and /PFO LED. JP2 CAP Additional Tests: 2. Apply a voltage of 3.0V to 27V across VIN and GND. 8. Move JP2 to OPEN for a faster Push Button power down time and repeat steps 1 through 8. 3. Push down on Push Button SW1 for a Turn On. 2P6V LED will turn on from the 2.6V output. 9. Move JP1 to TIE for an immediate Push Button shutdown. 4. Push down on Push Button SW1 for over 3 sec- onds for a turn off. /INT LED will momentarily turn on then turn off along with 2P6V LED. Figure 1. Proper Measurement Equipment Setup 2