ltc4350 Linear Technology Corporation, ltc4350 Datasheet - Page 4

• Manufacturer Part Number: ltc4350
• Description: Hot Swappable Load Share Controller
• Manufacturer: Linear Technology Corporation

PI FU CTIO S
UV (Pin 1): Undervoltage Pin. The threshold is set at
1.244V with a 24mV hysteresis. When the UV pin is pulled
high, the charge pump ramps the GATE pin. When the UV
pin is pulled low, the GATE pin will be pulled low.
OV (Pin 2): Overvoltage Pin. The threshold is set at 1.220V
with a 15mV hysteresis. When the OV pin is pulled high,
the GATE pin is pulled low. After a timer cycle, the STATUS
pin is pulled low until the OV pin is pulled low.
TIMER (Pin 3): Analog System Timing Generator Pin. This
pin is used to set the delay before the load sharing turns
on after the UV pin goes high. The other use for the TIMER
pin is to delay the indication of a fault on the STATUS pin.
LTC4350
TYPICAL PERFOR A CE CHARACTERISTICS
4
1.220
1.230
1.225
1.215
1.210
U
2.7
2.3
2.2
2.6
2.5
2.4
–50
0
Gain Pin Voltage vs Temperature
FB vs V
R
(V
V
T
CC
GAIN
A
R
= 25°C
+
= 5V
U
– V
–25
2
= 25k
R
CC
–
) = 100mV
4
TEMPERATURE (°C)
0
6
V
CC
U
25
(V)
8
50
10
W
75
12
4350 G10
4350 G07
U
100
14
1.230
1.215
1.210
1.225
1.220
13
12
10
11
9
8
6
7
–50
0
∆V
FB vs Temperature
T
A
V
GATE
= 25°C
CC
2
–25
= 5V
vs V
4
TEMPERATURE (°C)
0
CC
6
V
CC
When the timer is off, an internal N-channel shorts the
TIMER pin to ground. When the timer is turned on, a 2µA
or 6µA timer current (I
TIMER pin and the voltage starts to ramp up with a slope
given by: dV/dt = I
trip point (1.220V), the timer will be reset by pulling the
TIMER pin back to ground. The timer period is given by:
(1.220V • C
GAIN (Pin 4): Analog Output Pin. The voltage across the
R
a current from the GAIN pin. An external resistor on the
GAIN pin determines the voltage gain from the current
sense resistor to the GAIN pin.
25
(V)
+
8
and R
50
10
–
75
12
pins is divided by a 1k resistor and sourced as
T
4350 G11
4350 G08
)/I
TIMER
100
14
TIMER
.
13.0
11.5
11.0
TIMER
12.5
12.0
2.5
2.7
2.6
2.4
2.3
2.2
/C
–50
0
T
∆V
Gain PIn Voltage vs V
R
(V
T
. When the voltage reaches the
A
GAIN
V
) from V
R
GATE
= 25°C
CC
+
–25
2
– V
= 5V
= 25k
R
–
vs Temperature
) = 100mV
4
TEMPERATURE (°C)
0
CC
6
V
is connected to the
CC
25
(V)
8
CC
50
10
75
12
4350 G09
4350 G12
4350fa
100
14