DEMO MANUAL DC1836A LTC2955 Pushbutton On/Off Controller with Automatic Turn-On Description Demonstration circuit 1836A-A and 1836A-B feature the When the system receives an INT signal, it may use the LTC 2955-1 and LTC2995-2, respectively. The LTC2955 is power kill input to shut off power. If the pushbutton remains a micropower, pushbutton on/off controller that manages pressed for more than the configurable turn-off duration system power by generating a clean enable output from (3s or 32ms), the system power is forced off. the supply monitor input and the debounced pushbut- Design files for this circuit board are available at ton input. It features an interrupt output that notifies the DEMO MANUAL DC1836A h Dware s JumPEr S ETTing S DigiTAL COnn ECTiOnS Tmr PEri OD: Sets the amount of time the user has to En/EN: Active high (LTC2955-1), or active low (LTC2955- hold down the pushbutton in order to cause a shutdown 2) signal. Should go active either on a valid ON signal or event. It can either be set to 32ms or 3 seconds. with a debounced PB press. On Fun CTiOn : Connect to ON BLOCKED to block the ON INT: Goes low on a pushbutton press when EN/EN is pin falling edge from activating system turn-off. Connect active. Can be tied to KILL to turn off the part. to ON ACTIVE to allow both the ON pin rising and falling KILL: A low signal at this input will disable EN/EN. The edges to activate system turn-on and turn-off, respectively. TMR period jumper sets how long the input signal must Vin/On: Connects or disconnects VIN from ON. Unless be held low. external circuitry has been connected to ON, for ON to PgD: Power good output from the LTC2955. This pin function correctly, this should be set to ON. indicates the status of the ON pin in order to let the sys- KiLL: Ties or separates INT from KILL. Set to TIE for au- tem differentiate between pushbutton turn-on and supply tomatic shutdown when a long press on the pushbutton button turn-on events. is detected. LDO in: Chooses the input to the onboard LT3060 regula- tor. The user can either set it to VIN to have it connected to the VIN pin or EXTERNAL in order to have it driven by the LDO IN turret. See the Operating Principles section. Only for LED/monitor circuitry. EXTErn AL COnn ECTiOnS Signal connections are made via the row of turret posts along the edges of the board. gn D: (3 turrets) These turrets are connected directly to the ground planes. Vin: Connect a 1.6V to 36V power supply to this turret. On: Can be linked to VIN through the VIN/ON jumper, however, can also be externally connected to a power source. Is con- nected directly to the ON pin of the LTC2955. If the ON function jumper is set to active, this pin can be used to turn on the EN pin, or turn off the EN pin, depending on if the demo board is populated with an LTC2955-1 or LTC2955-2. PB: This pin is already driven by the pushbutton, however, if needed it can be driven by an external signal to simulate a pushbutton press. LDO in: Can be used to provide the LT3060 with power when the LDO IN jumper is set to external. LDO OuT: Output from the LT3060. The state of this can also be monitored at D1. dc1836af 2 etup ar