Datasheet LTC2951-1, LTC2951-2 (Linear Technology) - 3

LTC2951-1/LTC2951-2
ELECTRICAL CHARACTERISTICS The
l
denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VIN = 2.7V to 26.4V, unless otherwise noted. (Note 2) SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
VIN Supply Voltage Range Steady-State Operation l 2.7 26.4 V IIN VIN Supply Current System Power-On, VIN = 2.7V to 24V l 6 12 µA VUVL VIN Undervoltage Lockout VIN Falling l 2.2 2.3 2.4 V VUVL(HYST) VIN Undervoltage Lockout Hysteresis l 50 300 600 mV
Pushbutton, Enable (PB, EN/ EN)
VPB(MIN, MAX) PB Voltage Range Single-Ended l –1 26.4 V IPB PB Input Current 2.5V < VPB < 26.4V l ±1 µA VPB = 1V l –1 –6 –12 µA VPB = 0.6V l –3 –9 –15 µA VPB(VTH) PB Input Threshold PB Falling l 0.6 0.8 1 V tEN/EN, Lockout EN/EN Lockout Time (Note 5) Enable Released → Enable Asserted l 200 256 325 ms IEN/EN(LKG) EN/EN Leakage Current VEN/EN = 1V, Sink Current Off l ±0.1 µA VEN/EN(VOL) EN/EN Voltage Output Low IEN/EN = 3mA l 0.11 0.4 V VPB(VOC) PB Open-Circuit Voltage IPB = –1µA l 1 1.6 2 V
Timing Pins (KILLT, OFFT)
IKILLT, OFFT(PU) KILLT/OFFT Pull-Up Current VKILLT, OFFT = 0V l –2.4 –3 –3.6 µA IKILLT, OFFT(PD) KILLT/OFFT Pull-Down Current VKILLT, OFFT = 1.3V l 2.4 3 3.6 µA tDB, ON Turn-On Debounce Time PB Falling → Enable Asserted l 100 128 163 ms tDB, OFF Internal Turn-Off Debounce Time OFFT Pin Float, PB Falling → INT Falling l 26 32 41 ms tOFFT Additional Adjustable Turn-Off Time COFFT = 1500pF l 9 11.5 13.5 ms
µP Handshake Pins (INT, KILL)
IINT(LKG) INT Leakage Current VINT = 3V l ±1 µA VINT(VOL) INT Output Voltage Low IINT = 3mA l 0.11 0.4 V VKILL(TH) KILL Input Threshold Voltage KILL Falling l 0.57 0.6 0.63 V VKILL(HYST) KILL Input Threshold Hysteresis l 10 30 50 mV IKILL(LKG) KILL Leakage Current VKILL = 0.6V l ±0.1 µA tKILL(PW) KILL Minimum Pulse Width l 30 µs tKILL(PD) KILL Propagation Delay KILL Falling → Enable Released l 30 µs tKILL, ON BLANK KILL Turn-On Blanking (Note 3) KILL = Low, Enable Asserted → Enable Released l 400 512 650 ms tKILL, OFF DELAY Internal KILL Turn-Off Delay (Note 4) KILLT Pin Float, KILL = High, INT Asserted → l 100 128 163 ms Enable Released tKILL,OFF DELAY, Additional Adjustable KILL Turn-Off Delay CKILLT = 1500pF l 9 11.5 13.5 ms ADDITIONAL (Note 4)
Note 1:
Stresses beyond those listed under Absolute Maximum Ratings
Note 4:
The internal KILL turn-off delay (t may cause permanent damage to the device. Exposure to any Absolute KILL, OFF DELAY) is the default delay from the initiation of a power-off sequence (INT falling, KILL = high), Maximum Rating condition for extended periods may affect device to the release of the enable output. The additional, adjustable KILL turn-off reliability and lifetime. delay (t
Note 2:
All currents into pins are positive; all voltages are referenced to KILL, OFF DELAY, ADDITIONAL) uses an optional external capacitor (C GND unless otherwise noted. KILLT) to provide extra delay from INT falling to the release of the enable output. If the KILL input switches low at any time during KILL turn-off
Note 3:
The KILL turn-on blanking timer period is the waiting period delay, enable is released, thus turning off system power. immediately after the enable output is asserted. This blanking time allows sufficient time for the DC/DC converter and the µP to perform power-up
Note 5:
The enable lockout time is designed to allow an application to tasks. The KILL and PB inputs are ignored during this period. If KILL properly power down such that the next power-up sequence starts from a remains low at the end of this time period, the enable output is released, consistent powered down configuration. PB is ignored during this lockout thus turning off system power. This time delay does not include t time. This time delay does not include tDB, ON. DB,ON. 295112fb 3 Document Outline Features Applications Description Typical Application Absolute Maximum Ratings Pin Configuration Order information Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram Timing Diagrams Applications Information Typical Applications Package Description Revision History Typical Application Related Parts