Fairchild Semiconductor FAN2513S285X, FAN2513S27X, FAN2513S26X, FAN2513S25X, FAN2512SX Datasheet
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FAN2512, FAN2513
150 mA CMOS LDO Regulators with Fast Start Enable
Features
• Ultra Low Power Consumption
• Enable optimized for CDMA time phases
• 150 mV dropout voltage at 150 mA
• 25 µA ground current at 150 mA
• Enable/Shutdown Control
• SOT23-5 package
• Thermal limiting
• 300 mA peak current
Applications
• Cellular Phones and accessories
•PDAs
• Portable cameras and video recorders
• Laptop, notebook and palmtop computers
Description
The F AN2512/13 family of micropower lo w-dropout v oltage
regulators utilize CMOS technology to offer a new level of
cost-effective performance in GSM, TDMA, and CDMA
cellular handsets, Laptop and Notebook portable computers,
and other portable devices. Features include extremely low
power consumption and low shutdown current, low dropout
voltage, exceptional loop stability able to accommodate a
Block Diagrams
EN
V
IN
Bandgap
Error
Amplifier
p
V
OUT
ADJ
wide variety of external capacitors, and the compact SOT23-5
surface-mount package. In addition, the F AN2512/13 f amily
offer the fast power-cycle time required in CDMA handset
applications. These products offer significant improvements
over older BiCMOS designs and are pin-compatible with
many popular devices. The output is thermally protected
against overload.
The FAN2512 and FAN2513 devices are distinguished by
the assignment of pin 4:
FAN2512: pin 4 – ADJ, allowing the user to adjust the
output voltage over a wide range using an external voltage
divider.
FAN2512-XX: pin 4 – BYP, to which a bypass capacitor
may be connected for optimal noise performance. Output
voltage is fixed, indicated by the suffix XX.
FAN2513-XX: pin 4 – ERR
, a flag which indicates that the
output voltage has dropped below the specified minimum
due to a fault condition.
The standard fixed output voltages available are 2.5V, 2.6V,
2.7V, 2.8V , 2.85V, 3.0V , and 3.3V. Custom output voltage are
also available: please contact your local Fairchild Sales
Office for information.
EN
V
IN
Bandgap
Error
Amplifier
p
BYP
V
OUT
FAN2512
Thermal
Sense
GND
V
IN
Bandgap
FAN2513-XX
FAN2512-XX
EN
Error
Amplifier
Thermal
Sense
Thermal
Sense
ERR
p
V
OUT
GND
GND
REV. 1.1.7 2/14/03
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1:
0:
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PRODUCT SPECIFICATION FAN2512/FAN2513
Pin Assignments
15
V
IN
V
OUT
EN
2
3
4
ADJ/BYP/ERR
GND
Pin No. FAN2512 FAN2512-XX FAN2513-XX
1. V
IN
V
IN
2. GND GND GND
3. EN EN EN
4. ADJ BYP ERR
5. V
OUT
V
OUT
Pin Descriptions
Pin Name Pin No. Type Pin Function Description
ADJ 4 Input
BYP 4 Passive
ERR 4 Open drain FAN2513-XX Error. Error flag output.
EN 3 Digital Input Enable.
V
V
IN
OUT
1 Power in
5 Power out
GND 2 Power
FAN2512 Adjust. Ratio of potential divider from VOUT to ADJ
determines output voltage.
FAN2512-XX Bypass. Connect 470 pF capacitor for noise reduction.
Output voltage < 95% of nominal.
Output voltage > 95% of nominal.
Shutdown V
Enable V
OUT
OUT
.
Voltage Input. Supply voltage input.
Voltage Output. Regulated output voltage.
Ground.
V
V
OUT
IN
Functional Description
Designed utilizing CMOS process technology, the
FAN2512/13 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 1 Ω , resulting in an unusually low dropout voltage under load when
compared to older bipolar pass-transistor designs.
2
Protection circuitry is provided onboard for overload conditions. 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.
REV. 1.1.7 2/14/03
3
FAN2512/FAN2513 PRODUCT SPECIFICATION
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 output can then be
re-Enabled within 500µSec, fulfilling the fast power-c ycling
needs of CDMA applications. Depending on the model
selected, other control and status functions are available at
pin 4 to enhance the operation of the device. The adjustablevoltage versions 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 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 FAN2512/13 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 de grades re gulator
loop stability in older designs. While the improvements featured in the FAN2512/13 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 significant 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 superior 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 tantalum 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. Unlik e many other LDO regulators, the FAN2512/13
family of products are nearly insensitive to output capacitor
ESR. Stable operation will be achieved with a wide variety
of capacitors with ESR values ranging from 10m Ω to 10 Ω 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 (FAN2512 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, highquality 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 0.4V or less at the Enable pin will disable the output, reducing the quiescent output current to less
than 1µA, while a voltage of 2.0V or greater will enable the
device. If this shutdown function is not needed, the pin can
simply be connected to the V
will cause erratic operation.
Error Flag (FAN2513 Only)
To indicate conditions such as input voltage dropout
(low V
), overheating, or overloading (excessive output
IN
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
is less than 95% or the rated output volt-
OUT
age, as specified in the error trip level characteristics.
A logic pullup resistor of 100K Ω is recommended at this
output. The pin can be left disconnected if unused.
Thermal Protection
The FAN2512/13 is designed to supply high peak output
currents 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
pin. Allo wing this pin to float
IN
GND
OUT
.
REV. 1.1.7 2/14/03
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