LTC1470 Linear Technology, LTC1470 Datasheet - Page 5

• Manufacturer Part Number: LTC1470
• Description: Single and Dual PCMCIA Protected 3.3V/5V VCC Switches
• Manufacturer: Linear Technology

BLOCK
PIN
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
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
IN
U
(Pins 2, 10): 5V Input Supply Pins. The 5V
FUNCTIONS
EN0
EN1
U
DIAGRAM
TTL-TO-CMOS
TTL-TO-CMOS
CONVERTER
CONVERTER
U
W
(LTC1470 or 1/2 LTC1471)
BREAK-BEFORE-
MAKE SWITCH
AND CONTROL
IN
supply
OSCILLATOR
AND BIAS
should not be forced below ground. All four inputs have
about 100mV of built-in hysteresis to ensure clean switch-
ing between operating modes. The LTC1471 is designed
to operate without 12V power. The gates of the V
switches are powered by charge pumps from the 5V
supply pins (see Applications Information section for
more detail). The enable inputs should be turned off at
least 100 s before the 5V
that all NMOS switch gates are fully discharged and are in
the high impedance mode.
GND (Pins 5, 13): Ground Connections.
3V
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.
IN
(Pins 6, 7, 14, 15): 3V Input Supply Pins. The 3V
CONTROL LOGIC
CONTROL LOGIC
GATE CHARGE
GATE CHARGE
DISCHARGE
DISCHARGE
CHARGE
PUMP
AND
AND
LTC1470/LTC1471
CURRENT LIMIT
IN
AND THERMAL
SHUTDOWN
power is removed to ensure
0.14
0.12
5V
OUTPUT
3V
LTC1470-BD01
IN
IN
CC
NMOS
5
IN
IN