
FAN2514/FAN2515
PRODUCT SPECIFICATION
REV. 1.0.8 2/14/03
3
Depending on the model selected, a number of control and 
status functions are available to enhance the operation of the 
LDO regulator. An Enable pin, available on all devices, 
allows the user to shut down the regulator output to conserve 
power, reducing supply current to less than 1μA. The 
adjustable-voltage versions of the device utilize pin 4 to 
connect to an external voltage divider which feeds back to 
the regulator error amplifier, thereby setting the voltage as 
desired. Two other functions are available at pin 4 in the 
fixed-voltage versions: in noise-sensitive applications, an 
external Bypass capacitor connection is provided that allows 
the user to achieve optimal noise performance at the output, 
while the Error output functions as a diagnostic flag to 
indicate that the output voltage has dropped more than 5% 
below the nominal fixed voltage. 
Applications Information
External Capacitors – Selection
The FAN2514/15 allows the user to utilize a wide variety of 
capacitors compared to other LDO products. An innovative 
design approach offers significantly reduced sensitivity to 
ESR (Effective Series Resistance), which degrades regulator 
loop stability in older designs. While the improvements fea-
tured in the FAN2514/15 family greatly simplify the design 
task, capacitor quality still must be considered if the designer 
is to achieve optimal circuit performance. In general, 
ceramic capacitors offer superior ESR performance, at a 
lower cost and a smaller case size than tantalums. Those with 
X7R or Y5Vdielectric offer the best temperature coefficient 
characteristics. The combination of tolerance and variation 
over temperature in some capacitor types can result in signif-
icant variations, resulting in unstable performance over rated 
conditions.
Input Capacitor
An input capacitor of 2.2μF (nominal value) or greater, 
connected between the Input pin and Ground, located in 
close proximity to the device, will improve transient 
response and noise rejection. Higher values will offer supe-
rior input ripple rejection and transient response. An input 
capacitor is recommended when the input source, either a 
battery or a regulated AC voltage, is located far from the 
device. Any good quality ceramic, tantalum, or metal film 
capacitor will give acceptable performance, however tanta-
lum capacitors with a surge current rating appropriate to the 
application must be selected to avoid catastrophic failure. 
Output Capacitor
An output capacitor is required to maintain regulator loop 
stability. Unlike many other LDO regulators, the 
FAN2514/15 family of products are nearly insensitve to 
output capacitor ESR. Stable operation will be achieved with 
a wide variety of capacitors with ESR values ranging from 
10m
 to 10
 or more. Tantalum or aluminum electrolytic, 
or multilayer ceramic types can all be used. A nominal value 
of at least 1μF is recommended.
Bypass Capacitor (FAN2514 Only)
In the fixed-voltage configuration, connecting a capacitor 
between the bypass pin and ground can significantly reduce 
noise on the output. Values ranging from 470pF to 10nF can 
be used, depending on the sensitivity to output noise in the 
application. 
At the high-impedance Bypass pin, care must be taken in the 
circuit layout to minimize noise pickup, and capacitors must 
be selected to minimize current loading (leakage). Noise 
pickup from external sources can be considerable. Leakage 
currents into the Bypass pin will directly affect regulator 
accuracy and should be kept as low as possible; thus, high-
quality ceramic and film types are recommended for their 
low leakage characteristics. Cost-sensitive applications not 
concerned with noise can omit this capacitor. 
Control Functions
Enable Pin
Applying a voltage of 0.8V or less at the Enable pin will 
disable the output, reducing the quiescent output current to 
less than 1μA, while a voltage of 1.5V or greater will enable 
the device. If this shutdown function is not needed, the pin 
can simply be connected to the V
float will cause erratic operation.
IN
 pin. Allowing this pin to 
Error Flag (FAN2515 only)
To indicate conditions such as input voltage dropout 
(low V
IN
), overheating, or overloading (excessive output 
current), the ERR pin indicates a fault condition. It is an 
open-drain output which is HIGH when the voltage at V
is greater than 95% of the nominal rated output voltage and 
LOW when V
OUT
 is less than 95% or the rated output 
voltage, as specified in the error trip level characteristics. 
OUT
A logic pullup resistor of 100K
output. The pin can be left disconnected if unused. 
 is recommended at this 
Thermal Protection
The FAN2514/15 is designed to supply high peak output cur-
rents of up to 1A for brief periods, however this output load 
will cause the device temperature to increase and exceed 
maximum ratings due to power dissipation. During output 
overload conditions, when the die temperature exceeds the 
shutdown limit temperature of 150°C, onboard thermal 
protection will disable the output until the temperature drops 
below this limit, at which point the output is then re-enabled. 
During a thermal shutdown situation the user may assert the 
power-down function at the Enable pin, reducing power 
consumption to the minimum level I
GND
 · V
IN
.