LTC2960IDC-1-TRMPBF View Datasheet(PDF) - Linear Technology
Part Name
Description
MFG CO.
'LTC2960IDC-1-TRMPBF' PDF : 16 Pages View PDF
LTC2960
APPLICATIONS INFORMATION
When a supply voltage is abruptly connected to the input
resonant ringing can occur as a result of series inductance.
The peak voltage could rise to 2x the input supply but in
practice can reach 2.5x if a capacitor with a strong volt-
age coefficient is present. If a 12V supply is hot plugged
the resulting ringing could reach the abs max of VCC. Any
circuit with an input of more than 7V should be scrutinized
for ringing. Circuit board trace inductances of as little as
10nH can produce significant ringing.
One effective means to eliminate ringing is to include a
10–100Ω resistance in series with the supply input before
the VCC capacitor shown in Figure 7(b). This provides damp-
ing for the resonant circuit but imposes a time constant to
VCC. In Figure 7(b), the time constant of RS and C1 is 2μs.
VIN MAX 200V
RZ
143k
PWC1206LF143kJ*
Z1
BZX84C30
BV = 30V
VCC
C1
0.1μF
LTC2960
50V
VIN
RS
20
C1
0.1μF
50V
(a)
VCC
LTC2960
*TT-IRC
2960 F07
(b)
Figure 7. Operation with High Voltage Transients
and Hot Swapping
TYPICAL APPLICATIONS
Configurable Regulator UVLO and Low Battery
Indicator
In the circuit of Figure 8, the high voltage open drain
OUT output is used as a configurable UVLO signal for a
switching regulator. A Li-Ion battery can contain protec-
tion circuitry that open circuits its terminals through an
internal switch when it reaches 2.5V. With a threshold of
5.537V the LTC2960 OUT output disables the load before
this occurs in order to prevent damage to the batteries.
In addition to the UVLO signal, the LTC2960 provides a
low battery indicator for the system. Figure 9 shows an
alternative arrangement in which the LTC2960 monitors
the output of the 3.3V regulator to provide a reset signal.
Li-Ion +
4.2V
Li-Ion +
4.2V
R3
5.11M*
C1
0.1μF
25V
R2
49.9k
R1
348k
BUCK CONVERTER
VBAT
6V TO 8.4V
VCC
RT OUT
IN+
LTC2960-1
NOT ALL LT3991 COMPONENTS SHOWN
R4 VIN
VOUT
10M
LT3991
EN
GND
C2
47μF
16V
ADJ RST
MR
GND
2960 F08
VOUT
3.3V
R5
1M
LOW BATTERY
UVLO FALLING THRESHOLD = 5.537V
RESET FALLING THRESHOLD = 6.33V
*VISHAY-DALE CRCW SERIES 0603 1%
Figure 8. Configurable Regulator UVLO and Low Battery Indicator
2960f
12
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