Turn On Debounce
T YPICAL APPLICATION
F EATURES
A PPLICATIONS
D ESCRIPTION EN
2V/DIV
PB蝽卵
10ms/DIV
2950 TA01b
Controller
The L TC ®2950 is a micropower , wide input voltage range, push button ON/OFF controller . The part contains a push button input with independently programmable ON and OFF debounce times that control the toggling of an open drain enable output. The part also contains a simple micropro-cessor interface to allow for proper system housekeeping prior to power down. Under system fault conditions, an internal KILL timer ensures proper power down.The L TC2950 operates over a wide 2.7V to 26V input voltage range to accommodate a wide variety of input power supplies. Very low quiescent current (6μA typical) makes the L TC2950 ideally suited for battery powered applications. T wo versions of the part are available to ac-commodate either positive or negative enable polarities. The parts are available in either 8-lead 3mm × 2mm DFN or ThinSOT packages.
■
Portable Instrumentation Meters ■ Blade Servers
■ Portable Customer Service PDA ■ Desktop and Notebook Computers
■
汪伊涵Adjustable Push Button On/Off Timers ■ Low Supply Current: 6μA
■ Wide Operating Voltage Range: 2.7V to 26V ■
EN Output (L TC2950-1) Allows DC/DC Converter Control
排放因子■ EN Output (L TC2950-2) Allows Circuit Breaker Control ■ Simple Interface Allows Graceful μP Shut Down ■ High Input Voltage PB Pin with Internal Pull Up Resistor
■ ±10kV ESD HBM on PB Input
■ Accurate 0.6V Threshold on KILL Comparator Input ■ 8-Pin 3mm × 2mm DFN and ThinSOT TM Packages
V L , LT, LTC and LTM are registered trademarks of Linear Technology Corporation. ThinSOT is a trademark of Linear Technology Corporation. All other trademarks are the property of their respective owners.
A BSOLUTE MAXIMUM RATINGS Supply Voltage (V IN ) ..................................–0.3V to 33V Input Voltages
PB ............................................................–6V to 33V ONT ......................................................–0.3V to 2.7V OFFT ......................................................–0.3V to 2.7V KILL .........................................................–0.3V to 7V Output Voltages
INT .........................................................–0.3V to 10V EN/EN ....................................................–0.3V to 10V (Note 1)
Operating Temperature Range
L TC2950-C1 ..............................................0°C to 70°C L TC2950-C2 ..............................................0°C to 70°C L TC2950-I1 ..........................................–40°C to 85°C L TC2950-I2 ..........................................–40°C to 85°C Storage Temperature Range DFN Package .....................................–65°C to 125°C TSOT-23 ............................................–65°C to 150°C Lead Temperature (Soldering, 10 sec) ..................300°C
TOP VIEW
DDB8PACKAGE
8-LEAD (3mm s 2mm) PLASTIC DFN 5
6789
4
321GND ONT PB V IN INT EN/EN OFFT KILL
T JMAX = 125°C, θJA = 165°C/W EXPOSED PAD (PIN 9) UNCONNECTED
V IN 1
PB 2ONT 3GND 4
8 KILL 7 OFFT 6 EN/EN 5 INT
TOP VIEW
TS8 PACKAGE
8-LEAD PLASTIC TSOT-23T JMAX = 125°C, θJA = 140°C/W
P IN CONFIGURATION ORDER INFORMATION
Lead Free Finish
TAPE AND REEL (MINI)
TAPE AND REEL
PART MARKING*电子定时器
PACKAGE DESCRIPTION
TEMPERATURE RANGE L TC2950CDDB-1#TRMPBF L TC2950CDDB-1#TRPBF LBKP 8-Lead Plastic DFN 0°C to 70°C L TC2950CDDB-2#TRMPBF L TC2950CDDB-2#TRPBF LBNG 8-Lead Plastic DFN 0°C to 70°C L TC295ICDDB-1#TRMPBF L TC295ICDDB-1#TRPBF LBKP 8-Lead Plastic DFN –40°C to 85°C L TC295ICDDB-2#TRMPBF L TC295ICDDB-2#TRPBF LBNG 8-Lead Plastic DFN –40°C to 85°C L TC2950CTS8-1#TRMPBF L TC2950CTS8-1#TRPBF L TBKN 8-Lead Plastic TSOT-230°C to 70°C L TC2950CTS8-2#TRMPBF L TC2950CTS8-2#TRPBF L TBNF 8-Lead Plastic TSOT-230°C to 70°C L TC2950ITS8-1#TRMPBF L TC2950ITS8-1#TRPBF L TBKN 8-Lead Plastic TSOT-23–40°C to 85°C L TC2950ITS8-2#TRMPBF L TC2950ITS8-2#TRPBF L TBNF 8-Lead Plastic TSOT-23–40°C to 85°C
TRM = 500 pieces. *Temperature grades are identifi ed by a label on the shipping container.Consult LTC Marketing for parts specifi ed with wider operating temperature ranges.Consult LTC Marketing for information on lead based fi nish parts.
For more information on lead free part marking, go to: www.linear/leadfree/For more information on tape and reel specifi cations, go to: www.linear/tapeandreel/
The
● denotes the specifi cations which apply over the full operating temperature range, otherwise specifi cations are at T A = 25C. V IN = 2.7V to 26.4V, unless otherwise noted. (Note 2)
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS V IN Supply Voltage Range Steady State Operation● 2.726.4V I IN V IN Supply Current System Power On, V IN = 2.7V to 24V●612μA V UVL V IN Undervoltage Lockout V IN Falling● 2.2 2.3 2.4V V UVL(HYST)V IN Undervoltage Lockout
Hysteresis
50300600mV Push Button Pin (PB)
V PB(MIN, MAX)PB Voltage Range Single-Ended●–126.4V
I PB PB Input Current 2.5V < V PB < 26.4V
V PB = 1V
V PB = 0.6V ●
●
●
–1
–3
–6
–9
±1
–12
–15
μA
μA
μA
V PB(VTH)PB Input Threshold PB Falling●0.60.81V V PB(VOC)PB Open Circuit Voltage I PB = –1μA1 1.62V Debounce Timing Pins (ONT, OFFT)
I ONT, OFFT(PU)ONT/OFFT Pull Up Current V ONT, OFFT = 0V●–2.4–3–3.6μA I ONT, OFFT(PD)ONT/OFFT Pull Down Current V ONT, OFFT = 1.3V● 2.43 3.6μA t DB, On Internal Turn On Debounce Time ONT Pin Float, PB Falling → Enable Asserted●263241ms t ONT Additional Adjustable Turn On Time C ONT = 1500pF●911.513.5ms t DB, Off Internal Turn Off Debounce Time OFFT Pin Float, PB Falling →INT Falling●263241ms t OFFT Additional Adjustable Turn Off Time C OFFT = 1500pF●911.513.5ms μP Handshake Pins (INT, KILL)
I INT(LKG)INT Leakage Current V INT = 3V●±1μA V INT(VOL)INT Output Voltage Low I INT = 3mA●0.110.4V V KILL(TH)KILL Input Threshold Voltage KILL Falling●0.570.60.63V V KILL(HYST)KILL Input Threshold Hysteresis103050mV I KILL(LKG)KILL Leakage Current V KILL = 0.6V±0.1μA t KILL(PW)KILL Minimum Pulse Width●30μs t KILL(PD)KILL Propagation Delay KILL Falling → Enable Released●30μs t KILL, On Blank KILL Turn On Blanking (Note 3)KILL = Low, Enable Asserted → Enable Released●400512650ms t KILL, Off Delay KILL Turn Off Delay (Note 4)KILL = High, INT Asserted → Enable Released●80010241300ms t EN/EN, Lock Out EN/EN Lock Out Time (Note 5)Enable Released → Enable Asserted●200256325ms I EN/EN(LKG)EN/EN Leakage Current V EN/EN = 1V, Sink Current Off●±0.1μA V EN/EN(VOL)EN/EN Voltage Output Low I EN/EN = 3mA●0.110.4V E LECTRICAL CHARACTERISTICS
Note 1: Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. Exposure to any Absolute Maximum Rating condition for extended periods may affect device reliability and lifetime.
Note 2: All currents into pins are positive; all voltages are referenced to GND unless otherwise noted.
Note 3: The KILL turn on blanking timer period is the waiting period immediately after the enable outp
ut is asserted. This blanking time allows suffi cient time for the DC/DC converter and the μP to perform power up tasks. The KILL and PB inputs are ignored during this period. If KILL remains low
at the end of this time period, the enable output is released, thus turning off Note 4: The KILL turn off delay is the maximum delay from the initiation of a shutdown sequence (INT falling), to the release of the enable output. If the KILL input switches low at any time during this period, enable is released, thus turning off system power. This time is internally fi xed at 1024ms. This time delay does not include t DB, OFF or t OFFT.
Note 5: The enable lock out time is designed to allow an application to properly power down such that the next power up sequence starts from a consistent powered down confi guration. PB is ignored during this lock out time. This time delay does not include t DB, ON or t ONT.
Supply Current vs Temperature
Supply Current vs Supply Voltage
Internal Default Turn On
Debounce Time (t DB, ON ) vs V IN
Turn On Debounce Time (t DB, ON + t ONT ) vs ONT External Capacitor
ONT Pull-Down Current vs Temperature
Internal Default Turn Off
Debounce Time (t DB, OFF ) vs V IN
Turn Off Debounce Time (t DB, OFF + t OFFT ) vs OFFT External Capacitor
OFFT Pull-Down Current vs Temperature
PB Current vs PB Voltage
TYPICAL PERFORMANCE CHARACTERISTICS
TYPICAL PERFORMANCE CHARACTERISTICS
PB Voltage vs External PB Resistance to Ground
EN/EN V OL vs Current Load
EN (L TC2950-1) Voltage vs V IN
EN (L TC2950-2) Voltage vs V IN
PIN FUNCTIONS
V IN (Pin 1/Pin 4): Power Supply Input: 2.7V to 26.4V. PB (Pin 2/Pin 3): Push Button Input. Connecting PB to
ground through a momentary switch provides on/off
control via the EN/EN pin. An internal 100k pull-up resis-高压带电显示装置
tor connects to an internal 1.9V bias voltage. The rugged PB input can be pulled up to 26.4V externally without
consuming extra current.
ONT (Pin 3/Pin 2): Additional Adjustable Turn On Time
Input. Placing an external capacitor to ground determines
the additional time (beyond the internal default 32ms)
the PB pin must be held low before the enable output
is asserted. Floating this pin results in a default turn on
debounce time of 32ms.
GND (Pin 4/Pin 1): Device Ground.
INT (Pin 5/Pin 8): Open Drain Interrupt Output. After a push
button turn-off event is detected, the L TC2950 interrupts the
system (μP) by bringing the INT pin low. Once the system
fi nishes its power down and housekeeping tasks, it sets KILL low, which in turn releases the enable output. If at the end of the power down timer (1024ms) KILL is still high, the enable output is released immediately. INT may optionally be tied to KILL to release the enable output immediately after the turn-off event has been detected (INT = low). EN (L TC2950-1, Pin 6/Pin 7): Open Drain Enable Output. This pin is intended to enable system power. EN is as-serted high after a valid PB turn on event. EN is released low if: a) KILL is not driven high (by μP) within 512ms of the initial valid PB power turn-on event, b) KILL is driven low during normal operation, c) a second valid PB event (power turn-off) is detected. The operating range for this pin is 0V to 10V.EN (L TC2950-2, Pin 6/Pin 7): Open Drain Enable Output. This pin is intended to enable system power. EN is as-serted low after a valid PB turn-on event. EN releases high if: a) KILL is not driven high (by μP) within 512ms of the initial valid PB power turn-on event, b) KILL is driven low during normal operation, c) a second valid PB event (power turn-off) is detected. The operating range of this pin is 0V to 10V.
OFFT (Pin 7/Pin 6): Additional Adjustable Turn Off Time Input. A capacitor to ground determines the additional time (beyond the internal default 32ms) that the PB pin must be held low before initiating a power down sequence (INT falling). Floating this pin results in a default turn off time of 32ms.
KILL (Pin 8/Pin 5):KILL Input. Forcing KILL low releases the enable output. D uring system turn on, th
is pin is blanked by a 512ms internal timer to allow the system to pull KILL high. This pin has an accurate 0.6V threshold and can be used as a voltage monitor input.
Exposed Pad (Pin 9): Exposed Pad may be left open or connected to device ground.
(TSOT-23/DFN)
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