LTC4350_1 Datasheet, PDF (14/18 Pages) Linear Technology – Hot Swappable Load Share Controller

LTC4350
Applications Information
compensation capacitor C_P2 can be looked up in Table 1
using t_R. The value for the zero setting resistor, R_P1, is
150Ω. This value guarantees the zero is at or above the
crossover frequency.
Table 1
t_R
5µs
10µs
20µs
40µs
60µs
80µs
100µs
150µs
200µs
300µs
400µs
500µs
f_C = 0.35/t_R
70kHz
35kHz
17.5kHz
8.8kHz
5.8kHz
4.4kHz
3.5kHz
2.3kHz
1.8kHz
1.2kHz
0.9kHz
0.7kHz
C_P2
0.1µF
0.22µF
0.47µF
1µF
1.5µF
2.2µF
2.7µF
3.3µF
4.7µF
6.8µF
10µF
12µF
Other Applications
The application shown on the first page of this data sheet
assumes that the power supplies and the load reside on
one main board. If the system is a true N + 1 hot swappable
power supply, then the LTC4350 will reside with the power
supply on a daughter card that plugs into the main board.
In this case, the input and output capacitors need to be
hot swapped (see Figure 7). The output capacitors are Hot
Swap protected by the LTC4350. The input capacitors are
Hot Swap protected using the LT^®4250. Other Hot Swap
parts are described in Table 2.
Table 2
VOLTAGE RANGE
3.3V to 12V
3.3V to 15V
2.7V to 16.5V
9V to 80V
–20V to –80V
PART NUMBER
LTC1422 Single Channel
LTC1645 Dual Chanel
LTC1642 Overvoltage Protection
LTC1647 Dual Channel
LT1641 Positive High Voltage
LT4250 Negative High Voltage
In some cases, the output voltage is below the undervoltage
lockout of the LTC4350. In this case, an external supply
of 3.3V or greater needs to provide for the chip. Figure 8
shows a 1.5V output redundant power supply that uses
24V to 1.5V switching power supplies. The V_CC pin of
the LTC4350 can be driven from the INTV_CC pin of the
LTC1629.
4350fb
14