LT1312 Linear Technology, LT1312 Datasheet - Page 5

• Manufacturer Part Number: LT1312
• Description: Single PCMCIA VPP Driver/Regulator
• Manufacturer: Linear Technology

BLOCK
PIN
Supply Pin: Power is supplied to the device through the
supply pin. The supply pin should be bypassed to ground
if the device is more than 6 inches away from the main
supply capacitor. A bypass capacitor in the range of 0.1 F
to 1 F is sufficient. The supply voltage to the LT1312 can
be loosely regulated between 13V and 20V. See Applica-
tions Information section for more detail.
VPP
PCMCIA card VPP pins which are typically tied together
at the card socket. The VPP
to approximately 330mA. Thermal shutdown provides a
second level of protection. A 1 F to 10 F tantalum output
capacitor is recommended. See Applications Informa-
tion section for more detail on output capacitor consid-
erations.
Input Enable Pins: The two digital input pins are high
impedance inputs with approximately 20 A input current
U
OUT
FUNCTIONS
Pin: This regulated output supplies power to the
U
DIAGRAM
V
CC
SENSE
U
EN0
EN1
V
S
4V
W
OUT
+
–
output is current limited
LOGIC CONTROL
LOW DROPOUT
REGULATOR
VOLTAGE
LINEAR
at 2.4V. The input thresholds are compatible with CMOS
controllers and can be driven from either 5V or 3.3V
CMOS logic. ESD protection diodes limit input excursions
to 0.6V below ground.
VALID Output Pin: This pin is an open-collector NPN
output which is driven low when the VPP
regulation, i.e., when it is above 11V. An external 51k pull-
up resistor is connected between this output and the same
5V or 3.3V logic supply powering the PCMCIA compatible
control logic.
V
automatically switches the VPP
pending upon the voltage sensed at the PCMCIA card
socket V
mately 30 A. For 5V only operation, connect the Sense pin
directly to ground. An ESD protection diode limits the
input voltage to 0.6V below ground.
CC
Sense Pin: A built-in comparator and 4V reference
11V
CC
pin. The input current for this pin is approxi-
+
–
LT1312 BD
OUT
VPP
VALID
OUT
from 5V to 3.3V de-
OUT
LT1312
pin is in
5