Datasheet

4
LTC1470/LTC1471
14701fa
TYPICAL PERFORMANCE CHARACTERISTICS
U
W
PIN FUNCTIONS
UUU
LTC1470
OUT (Pins 1, 8): Output Pins. The outputs of the LTC1470
are switched between three operating states: OFF, 3.3V
and 5V. These pins are protected against accidental short
circuits to ground by SafeSlot current limit circuitry which
protects the socket, the card, and the system power
supplies against damage. A second level of protection is
provided by thermal shutdown circuitry which protects
both switches against over-temperature conditions.
5V
IN
(Pin 2): 5V Input Supply Pin. The 5V
IN
supply pin
serves two purposes. The first purpose is as the power
supply input for the 5V NMOS switch. The second purpose
is to provide power for the input, gate drive, and protection
circuitry for both the 3.3V and 5V V
CC
switches. This pin
must therefore be continuously powered.
EN1, EN0 (Pins 3, 4): Enable Inputs. The two V
CC
Enable
inputs are designed to interface directly with industry
standard PCMCIA controllers and are high impedance
CMOS gates with ESD protection diodes to ground, and
should not be forced above 5V
IN
or below ground. Both
inputs have about 100mV of built-in hysteresis to ensure
clean switching between operating modes. The LTC1470
is designed to operate without 12V power. The gates of the
V
CC
NMOS switches are powered by charge pumps from
the 5V
IN
supply pins (see Applications Information section
for more detail). The Enable inputs should be turned off
(both asserted high or both asserted low) at least 100µs
before the 5V
IN
power is removed to ensure that both V
CC
NMOS switch gates are fully discharged and both switches
are in the high impedance mode.
GND (Pin 5): Ground Connection.
3V
IN
(Pins 6, 7): 3V Input Supply Pins. The 3V
IN
supply
pins serve as the power supply input for the 3.3V switches.
These pins do not provide any power to the internal control
circuitry and therefore do not consume any power when
unloaded or turned off.
JUNCTION TEMPERATURE (°C)
0
0
5V SWITCH RESISTANCE (Ω)
0.05
0.10
0.15
0.20
0.25
0.30
25 50 75 100
1470/71 G06
125
PROGRAMMED
TO 5V
5V Switch Resistance
TIME (ms)
–0.2
INRUSH CURRENT (A)OUTPUT VOLTAGE (V)
0
1
1.4
1470/71 G08
6
4
0
0.2
0.6
1.0
2
3
2
0
0.4
0.8
1.2
C
OUT
= 15µF
R
OUT
= 10Ω
T
J
= 25°C
CURRENT
LIMITED
C
OUT
= 150µF
R
OUT
= 10Ω
Inrush Current (5V Switch)Inrush Current (3.3V Switch)
TIME (ms)
–0.2
INRUSH CURRENT (A)OUTPUT VOLTAGE (V)
0
1
1.4
1470/71 G09
6
4
0
0.2
0.6
1.0
2
3
2
0
0.4
0.8
1.2
T
J
= 25°C
C
OUT
= 15µF
R
OUT
= 6.6Ω
C
OUT
= 150µF
R
OUT
= 6.6Ω
C
OUT
= 150µF
R
OUT
= 6.6Ω
(LTC1470 or 1/2 LTC1471)