LTC1470/LTC1471
PIN FUNCTIONS
LTC1471
AOUT, BOUT(Pins 1, 16, 8, 9):
Output Pins. The outputs
of the LTC1471 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.
5V
IN
(Pins 2, 10):
5V Input Supply Pins. The 5V
IN
supply
pins serve two purposes. The first purpose is as the power
supply input for the 5V NMOS switches. The second
purpose is to provide power for the input, gate drive, and
protection circuitry. These pins must therefore be con-
tinuously powered.
EN1, EN0 (Pins 3, 4, 11, 12):
Enable Inputs. The 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. All four
inputs have about 100mV of built-in hysteresis to ensure
clean switching between operating modes. The LTC1471
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 at
least 100µs before the 5V
IN
power is removed to ensure
that all NMOS switch gates are fully discharged and are in
the high impedance mode.
GND (Pins 5, 13):
Ground Connections.
3V
IN
(Pins 6, 7, 14, 15):
3V Input Supply Pins. The 3V
IN
supply pins serve as the power supply input for the 3.3V
switches. These pins do not not provide any power to the
internal control circuitry, and therefore, do not consume
any power when unloaded or turned off.
BLOCK DIAGRAM
EN0
TTL-TO-CMOS
CONVERTER
EN1
TTL-TO-CMOS
CONVERTER
W
U
U
U
(LTC1470 or 1/2 LTC1471)
5V
IN
GATE CHARGE
AND
DISCHARGE
CONTROL LOGIC
0.14Ω
BREAK-BEFORE-
MAKE SWITCH
AND CONTROL
OSCILLATOR
AND BIAS
CHARGE
PUMP
CURRENT LIMIT
AND THERMAL
SHUTDOWN
OUTPUT
GATE CHARGE
AND
DISCHARGE
CONTROL LOGIC
0.12Ω
3V
IN
LTC1470-BD01
14701fa
5
LINER [ LINEAR TECHNOLOGY ]
