Datasheet LTC2956 (Analog Devices) - 7
| Fabricante | Analog Devices |
| Descripción | Wake-Up Timer with Pushbutton Control |
| Páginas / Página | 28 / 7 — PIN FUNCTIONS EN:. ONMAX:. EN:. PB:. PBOUT:. Exposed Pad (QFN only):. … |
| Formato / tamaño de archivo | PDF / 325 Kb |
| Idioma del documento | Inglés |
PIN FUNCTIONS EN:. ONMAX:. EN:. PB:. PBOUT:. Exposed Pad (QFN only):. PERIOD:. GND:. LONG:. RANGE:. SLEEP:. OFFALERT:. ONALERT:. IN:
Línea de modelo para esta hoja de datos
- LTC2956CMS-1#PBF LTC2956CMS-1#PBF LTC2956CMS-1#TRPBF LTC2956CMS-1#TRPBF LTC2956CMS-2#PBF LTC2956CMS-2#PBF LTC2956CMS-2#TRPBF LTC2956CMS-2#TRPBF LTC2956CUD-1#PBF LTC2956CUD-1#PBF LTC2956CUD-1#TRPBF LTC2956CUD-1#TRPBF LTC2956CUD-2#PBF LTC2956CUD-2#PBF LTC2956CUD-2#TRPBF LTC2956CUD-2#TRPBF LTC2956IMS-1#PBF LTC2956IMS-1#PBF LTC2956IMS-1#TRPBF LTC2956IMS-1#TRPBF LTC2956IMS-2#PBF LTC2956IMS-2#PBF LTC2956IMS-2#TRPBF LTC2956IMS-2#TRPBF LTC2956IUD-1#PBF LTC2956IUD-1#PBF LTC2956IUD-1#TRPBF LTC2956IUD-1#TRPBF LTC2956IUD-2#PBF LTC2956IUD-2#PBF LTC2956IUD-2#TRPBF LTC2956IUD-2#TRPBF
Versión de texto del documento
LTC2956
PIN FUNCTIONS EN:
Enable Output (LTC2956-1). EN is an active high output mode to RUN mode. The pin stays low while the EN pin to control the turn-on/off of a load. Connect this pin to is high and it can be used as an input to the system to the RUN or SHUTDOWN pin of a voltage regulator. The request for initial boot up routine. This pin may be left LTC2956-1 pulls EN high through an internal 900k resis- open if unused. tor and Schottky diode to a 3.3V regulated supply when
ONMAX:
Maximum Awake Timer Capacitor Input. Connect the pushbutton is pressed or when the wake-up period a capacitor from this pin to GND adjust the maximum is reached. EN pulls low during the Sleep state. This pin allowed awake time (t may be left open if unused. ONMAX) at 13.3ms/nF. If this pin is left floating, the minimum awake time is limited to 8ms.
EN:
Inverted Enable Output (LTC2956-2). EN is an active Tie this pin to GND if unused. low output to control the turn-on/off of the system power.
PB:
Pushbutton Input. This is an active low input with a It may drive a voltage regulator’s active low enable input, 900kΩ pull-up to an internal 3.3V regulated supply. Con- or it may drive the gate of a P-channel MOSFET directly. nect one terminal of the pushbutton switch to this pin and In the Sleep state, the LTC2956-2 pulls this pin to VIN connect the other terminal of a pushbutton switch to GND. through an internal 900k resistor. The LTC2956-2 pulls The pin may be left open if unused. EN to GND when the pushbutton is pressed or when the wake-up timer period is reached. This pin may be left
PBOUT:
Debounced Pushbutton Open Drain Output. This open if unused. pin follows the debounced PB input. This pin may be left open if unused.
Exposed Pad (QFN only):
Exposed Pad. Leave open or connect to device ground.
PERIOD:
Wake-Up Timer Adjust Input. Connect a resistor from the PERIOD pin to GND to adjust the wake-up timer
GND:
Device Ground. period. See the Application Section for resistor selection
LONG:
Long Power Down Time Selection Input. Connect a information. resistor from the LONG pin to GND. Together with the 100k
RANGE:
Wake-Up Timer Range Selection Input. Connect a resistor between the RANGE and LONG pin, this adjusts resistor from the RANGE pin to GND and a 100k resistor the tLONG power down time (tLONG can be adjusted from between the RANGE and LONG pin to choose the wake- 128ms to 16.4s). If SLEEP is pulled high or PB is pulled up timer period range setting. See Application Section for low longer than tLONG, the part goes into SHUTDOWN information about the resistor selection. mode. See Applications Information for details.
SLEEP:
SLEEP Input. The SLEEP input is active during
OFFALERT:
Off Alert Open Drain Output. The LTC2956 RUN mode. In the Awake state, a falling edge at the SLEEP pulls this pin low for 1 second (tOFF) whenever the part input will pull EN low (EN high) and put the system into goes from RUN mode to SHUTDOWN mode. This pin can the Sleep state. If the SLEEP input goes high during the be connected to the interrupt input of the system (with a Sleep state, the LTC2956 re-enters the Awake state and pull-up resistor to the system supply) to alert the system pulls EN high (EN low) to turn on the system. Holding before shutdown. It can also be used to drive an external SLEEP high for more than t LED to give a visual indication. This pin may be left open LONG will force the system into the SHUTDOWN mode. If unused, tie SLEEP to GND, and if unused. use the ONMAX pin to control the awake time.
ONALERT:
On Alert Open Drain Output. The LTC2956 pulls
V
this pin low whenever the part goes from SHUTDOWN
IN:
Power Supply Input (1.5V to 36V). 2956fa For more information www.linear.com/LTC2956 7
PIN FUNCTIONS EN:
Enable Output (LTC2956-1). EN is an active high output mode to RUN mode. The pin stays low while the EN pin to control the turn-on/off of a load. Connect this pin to is high and it can be used as an input to the system to the RUN or SHUTDOWN pin of a voltage regulator. The request for initial boot up routine. This pin may be left LTC2956-1 pulls EN high through an internal 900k resis- open if unused. tor and Schottky diode to a 3.3V regulated supply when
ONMAX:
Maximum Awake Timer Capacitor Input. Connect the pushbutton is pressed or when the wake-up period a capacitor from this pin to GND adjust the maximum is reached. EN pulls low during the Sleep state. This pin allowed awake time (t may be left open if unused. ONMAX) at 13.3ms/nF. If this pin is left floating, the minimum awake time is limited to 8ms.
EN:
Inverted Enable Output (LTC2956-2). EN is an active Tie this pin to GND if unused. low output to control the turn-on/off of the system power.
PB:
Pushbutton Input. This is an active low input with a It may drive a voltage regulator’s active low enable input, 900kΩ pull-up to an internal 3.3V regulated supply. Con- or it may drive the gate of a P-channel MOSFET directly. nect one terminal of the pushbutton switch to this pin and In the Sleep state, the LTC2956-2 pulls this pin to VIN connect the other terminal of a pushbutton switch to GND. through an internal 900k resistor. The LTC2956-2 pulls The pin may be left open if unused. EN to GND when the pushbutton is pressed or when the wake-up timer period is reached. This pin may be left
PBOUT:
Debounced Pushbutton Open Drain Output. This open if unused. pin follows the debounced PB input. This pin may be left open if unused.
Exposed Pad (QFN only):
Exposed Pad. Leave open or connect to device ground.
PERIOD:
Wake-Up Timer Adjust Input. Connect a resistor from the PERIOD pin to GND to adjust the wake-up timer
GND:
Device Ground. period. See the Application Section for resistor selection
LONG:
Long Power Down Time Selection Input. Connect a information. resistor from the LONG pin to GND. Together with the 100k
RANGE:
Wake-Up Timer Range Selection Input. Connect a resistor between the RANGE and LONG pin, this adjusts resistor from the RANGE pin to GND and a 100k resistor the tLONG power down time (tLONG can be adjusted from between the RANGE and LONG pin to choose the wake- 128ms to 16.4s). If SLEEP is pulled high or PB is pulled up timer period range setting. See Application Section for low longer than tLONG, the part goes into SHUTDOWN information about the resistor selection. mode. See Applications Information for details.
SLEEP:
SLEEP Input. The SLEEP input is active during
OFFALERT:
Off Alert Open Drain Output. The LTC2956 RUN mode. In the Awake state, a falling edge at the SLEEP pulls this pin low for 1 second (tOFF) whenever the part input will pull EN low (EN high) and put the system into goes from RUN mode to SHUTDOWN mode. This pin can the Sleep state. If the SLEEP input goes high during the be connected to the interrupt input of the system (with a Sleep state, the LTC2956 re-enters the Awake state and pull-up resistor to the system supply) to alert the system pulls EN high (EN low) to turn on the system. Holding before shutdown. It can also be used to drive an external SLEEP high for more than t LED to give a visual indication. This pin may be left open LONG will force the system into the SHUTDOWN mode. If unused, tie SLEEP to GND, and if unused. use the ONMAX pin to control the awake time.
ONALERT:
On Alert Open Drain Output. The LTC2956 pulls
V
this pin low whenever the part goes from SHUTDOWN
IN:
Power Supply Input (1.5V to 36V). 2956fa For more information www.linear.com/LTC2956 7