LTC2950ITS8-2#TRPBF Linear Technology, LTC2950ITS8-2#TRPBF Datasheet - Page 12

• Manufacturer Part Number: LTC2950ITS8-2#TRPBF
• Description: IC PB ON/OFF CONTROLLER TSOT23-8
• Manufacturer: Linear Technology

Specifications of LTC2950ITS8-2#TRPBF

• Applications: Push Button, On/Off Controller
• Voltage - Supply: 2.7 V ~ 26.4 V
• Current - Supply: 6µA
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: TSOT-23-8, TSOT-8
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Voltage - Input: -

LTC2950-1/LTC2950-2
applicaTions inForMaTion
Voltage Monitoring with KILL Input
The KILL pin can be used as a voltage monitor. Figure 5
shows an application where the KILL pin has a dual function.
It is driven by a low leakage open drain output of the µP . It
is also connected to a resistor divider that monitors battery
voltage (V
value, the voltage at the KILL pin falls below 0.6V and the
EN pin is quickly pulled low. Note that the resistor values
should be as large as possible, but small enough to keep
Typical applicaTions
12
The following equations describe the turn on and turn
off times. C
capacitors:
High Voltage Pins
The V
PB can, additionally, operate below ground (–6V) without
latching up the device. PB has an ESD HBM rating of ±10kV.
0.1µF
t
t
BD,ON
BD,OFF
C4
IN
V
Figure 5. Input Voltage Monitoring with KILL Input
IN
*OPTIONAL
**SHDN INTERNALLY PULLED UP BY THE LT1767-3.3
9V
and PB pins can operate at voltages up to 26.4V.
+ t
IN
+ t
V
PB
GND ONT
5.4V THRESHOLD
ONT
). When the battery voltage falls below the set
IN
ONT
OFFT
LTC2950-1
and C
= 32ms + 1ms + (6.7x10
= 32ms + 1ms + (6.7x10
C
0.033µF
ONT
OFFT
*
OFFT
KILL
INT
EN
are the external programming
C
0.033µF
OFFT
806k
100k
1%
1%
R3
R2
*
V
SHDN**
IN
LT1767-3.3
R1
10k
6
6
V
) • C
) • C
OUT
INT
KILL
(OPEN DRAIN)
ONT
OFFT
µP
2950 F05
3.3V
If the pushbutton switch connected to PB exhibits high
leakage current, then an external pull-up resistor to V
recommended. Furthermore, if the pushbutton switch is
physically located far from the LTC2950 PB pin, parasitic
capacitances may couple onto the high impedance PB
input. Additionally, parasitic series inductance may cause
unpredictable ringing at the PB pin. Placing a 5k resistor
from the PB pin to the pushbutton switch would mitigate
parasitic inductance problems. Placing a 0.1µF capacitor
on the PB pin would lessen the impact of parasitic capaci-
tive coupling.
leakage currents from tripping the 0.6V KILL comparator.
The DC/DC converter shown has an internal pull-up current
on its SHDN pin. A pull-up resistor on EN is thus not needed.
Operation Without µP
Figure 6 shows how to connect the KILL pin when there
is no circuitry available to drive it. The minimum pulse
width detected is 30µs. If there are glitches on the resistor
pull-up voltage that are wider than 30µs and transition
0.1µF
C4
V
IN
*OPTIONAL
**SHDN INTERNALLY PULLED UP BY THE LT1767-3.3
9V
GND ONT
V
PB
IN
LTC2950-1
Figure 6. No µP Application
C
0.033µF
ONT
*
OFFT
KILL
INT
EN
C
0.033µF
OFFT
*
V
SHDN**
IN
LT1767-3.3
V
OUT
+
R1
100k
C3*
0.01µF
2950 F06
295012fd
3.3V
IN
is