FAN2518 Datasheet, PDF (2/10 Pages) Fairchild Semiconductor – 50 mA CMOS LDO Regulators with Fast Start Enable

PRODUCT SPECIFICATION
Pin Assignments
FAN2518/FAN2519
V_IN 1
GND 2
EN 3
5 V_OUT
4 ADJ/BYP/ERR
Pin No.
1.
2.
3.
4.
5.
FAN2518
V_IN
GND
EN
ADJ
V_OUT
FAN2518-XX
V_IN
GND
EN
BYP
V_OUT
FAN2519-XX
V_IN
GND
EN
ERR
V_OUT
Pin Descriptions
Pin Name Pin No. Type
ADJ
4
Input
BYP
ERR
4
Passive
4
Open drain
EN
3
Digital Input
V_IN
V_OUT
GND
1
Power in
5
Power out
2
Power
Pin Function Description
FAN2518 Adjust. Ratio of potential divider from VOUT to ADJ
determines output voltage.
FAN2518-XX Bypass. Connect 470 pF capacitor for noise reduction.
FAN2519-XX Error. Error flag output.
0: Output voltage < 95% of nominal.
1: Output voltage > 95% of nominal.
Enable.
0: Shutdown V_OUT.
1: Enable V_OUT.
Voltage Input. Supply voltage input.
Voltage Output. Regulated output voltage.
Ground.
Functional Description
Designed utilizing CMOS process technology, the
FAN2518/19 family of products are carefully optimized for
use in compact battery-powered devices, offering a unique
combination of low power consumption, extremely low
dropout voltages, high tolerance for a variety of output
capacitors, and the ability to disable the output to less than
1µA under user control. In the circuit, a difference amplifier
controls the current through a series-pass P-Channel
MOSFET, comparing the load voltage at the output with an
onboard low-drift bandgap reference. The series resistance
of the pass P-Channel MOSFET is approximately 1Ω, result-
ing in an unusually low dropout voltage under load when
compared to older bipolar pass-transistor designs.
Protection circuitry is provided onboard for overload condi-
tions. In conditions where the device reaches temperatures
exceeding the specified maximums, an onboard circuit shuts
down the output, where it remains suspended until it has
cooled before re-enabling. The user is also free to shut down
the device using the Enable control pin at any time.
Careful design of the output regulator amplifier assures loop
stability over a wide range of ESR values in the external
output capacitor. A wide range of values and types can be
accommodated, allowing the user to select a capacitor
meeting his space, cost, and performance requirements,
and enjoy reliable operation over temperature, load, and
tolerance variations.
2
REV. 1.0.6 2/14/03