Fairchild FAN2508SX 50 ma cmos ldo regulator Datasheet

www.fairchildsemi.com
FAN2508, FAN2509
50 mA CMOS LDO Regulators
Features
•
•
•
•
•
•
•
wide variety of external capacitors, and the compact SOT23-5
surface-mount package. The FAN2508/09 family of products
offer significant improvements over older BiCMOS designs
and are pin-compatible with many popular devices. The
output is thermally protected against overload.
Ultra Low Power Consumption
50 mV dropout voltage at 50 mA
25 µA ground current at 50 mA
Enable/Shutdown Control
SOT23-5 package
Thermal limiting
300 mA peak current
The FAN2508 and FAN2509 devices are distinguished by
the assignment of pin 4:
FAN2508: pin 4 – ADJ, allowing the user to adjust the
output voltage over a wide range using an external voltage
divider.
Applications
•
•
•
•
Cellular Phones and accessories
PDAs
Portable cameras and video recorders
Laptop, notebook and palmtop computers
FAN2508-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.
Description
The FAN2508/09 family of micropower low-dropout voltage
regulators utilize CMOS technology to offer a new level of
cost-effective performance in GSM and TDMA 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
FAN2509-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.
Block Diagrams
EN
EN
VIN
VIN
Bandgap
Error
Amplifier
BYP
Bandgap
p
VOUT
Error
Amplifier
p
VOUT
ADJ
Thermal
Sense
Thermal
Sense
GND
FAN2508
GND
FAN2508-XX
EN
VIN
ERR
Bandgap
Error
Amplifier
p
VOUT
Thermal
Sense
GND
FAN2509-XX
REV. 1.0.6 2/14/03
PRODUCT SPECIFICATION
FAN2508/FAN2509
Pin Assignments
VIN
1
GND
2
EN
3
5
VOUT
4
ADJ/BYP/ERR
Pin No.
FAN2508
FAN2508-XX
FAN2509-XX
1.
VIN
VIN
VIN
2.
GND
GND
GND
3.
EN
EN
EN
4.
ADJ
BYP
ERR
5.
VOUT
VOUT
VOUT
Pin Descriptions
Pin Name
Pin No.
Type
Pin Function Description
ADJ
4
Input
FAN2508 Adjust. Ratio of potential divider from VOUT to ADJ
determines output voltage.
BYP
4
Passive
FAN2508-XX Bypass. Connect 470 pF capacitor for noise reduction.
ERR
4
Open drain
FAN2509-XX Error. Error flag output.
0: Output voltage < 95% of nominal.
1: Output voltage > 95% of nominal.
EN
3
Digital Input
Enable.
0: Shutdown VOUT.
1: Enable VOUT.
VIN
1
Power in
Voltage Input. Supply voltage input.
VOUT
5
Power out
Voltage Output. Regulated output voltage.
GND
2
Power
Ground.
Functional Description
Designed utilizing CMOS process technology, the
FAN2508/09 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,
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
accomodated, 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. 1.0.6 2/14/03
FAN2508/FAN2509
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.
PRODUCT SPECIFICATION
Bypass Capacitor (FAN2508 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.
Applications Information
Control Functions
External Capacitors – Selection
The FAN2508/09 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 featured in the FAN2508/09 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. Unlike many other LDO regulators, the
FAN2508/09 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
10mΩ to 10Ω or more. Tantalum or aluminum electrolytic,
or multilayer ceramic types can all be used. A nominal value
of at least 1µF is recommended.
REV. 1.0.6 2/14/03
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 VIN pin. Allowing this pin to
float will cause erratic operation.
Error Flag (FAN2509 only)
To indicate conditions such as input voltage dropout
(low VIN), overheating, or overloading (excessive output current), the ERR pin indicates a fault condition. It is an opendrain output which is HIGH when the voltage at VOUT is
greater than 95% of the nominal rated output voltage and
LOW when VOUT is less than 95% or the rated output voltage, as specified in the error trip level characteristics.
A logic pullup resistor of 100KΩ is recommended at this
output. The pin can be left disconnected if unused.
Thermal Protection
The FAN2508/09 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 IGND · VIN.
3
PRODUCT SPECIFICATION
Thermal Characteristics
The FAN2508/09 is designed to supply 50mA at the
specified output voltage with an operating die (junction)
temperature of up to 125°C. Once the power dissipation and
thermal resistance is known, the maximum junction
temperature of the device can be calculated. While the power
dissipation is calculated from known electrical parameters,
the thermal resistance is a result of the thermal characteristics of the compact SOT23-5 surface-mount package and the
surrounding PC Board copper to which it is mounted.
The power dissipation is equal to the product of the input-tooutput voltage differential and the output current plus the
ground current multiplied by the input voltage, or:
P D = ( V IN – V OUT )I OUT + V IN I GND
The ground pin current IGND can be found in the charts
provided in the Electrical Characteristics section.
The relationship describing the thermal behavior of the
package is:
 T J ( max ) – T A 
P D ( max ) =  ------------------------------- 
θ JA


where TJ(max) is the maximum allowable junction temperature of the die, which is 125°C, and TA is the ambient operating temperature. θJA is dependent on the surrounding PC
board layout and can be empirically obtained. While the θJC
(junction-to-case) of the SOT23-5 package is specified at
130°C /W, the θJA of the minimum PWB footprint will be at
least 235°C /W. This can be improved upon by providing a
heat sink of surrounding copper ground on the PWB.
Depending on the size of the copper area, the resulting θJA
can range from approximately 180°C /W for one square inch
to nearly 130°C /W for 4 square inches. The addition of
backside copper with through-holes, stiffeners, and other
enhancements can also aid in reducing this value. The heat
contributed by the dissipation of other devices located
nearby must be included in design considerations.
Once the limiting parameters in these two relationships have
been determined, the design can be modified to ensure that
the device remains within specified operating conditions.
If overload conditions are not considered, it is possible for
4
FAN2508/FAN2509
the device to enter a thermal cycling loop, in which the
circuit enters a shutdown condition, cools, re-enables, and
then again overheats and shuts down repeatedly due to an
unmanaged fault condition.
Operation of Adjustable Version
The adjustable version of the FAN2508/09 includes an input
pin ADJ which allows the user to select an output voltage
ranging from 1.8V to near VIN, using an external resistor
divider. The voltage VADJ presented to the ADJ pin is fed to
the onboard error amplifier which adjusts the output voltage
until VADJ is equal to the onboard bandgap reference voltage
of 1.32V(typ). The equation is:
R upper
V OUT = 1.32V × 1 + ---------------R lower
The total value of the resistor chain should not exceed
250KΩ total to keep the error amplifier biased during
no-load conditions. Programming output voltages very near
VIN need to allow for the magnitude and variation of the
dropout voltage VDO over load, supply, and temperature
variations. Note that the low-leakage FET input to the
CMOS Error Amplifier induces no bias current error to the
calculation.
General PWB Layout Considerations
To achieve the full performance of the device, careful circuit
layout and grounding technique must be observed. Establishing a small local ground, to which the GND pin, the output
and bypass capacitors are connected, is recommended, while
the input capacitor should be grounded to the main ground
plane. The quiet local ground is then routed back to the main
ground plane using feedthrough vias. In general, the highfrequency compensation components (input, bypass, and
output capacitors) should be located as close to the device as
possible. The proximity of the output capacitor is especially
important to achieve optimal noise compensation from the
onboard error amplifier, especially during high load conditions. A large copper area in the local ground will provide the
heat sinking discussed above when high power dissipation
significantly increases the temperature of the device.
Component-side copper provides significantly better thermal
performance for this surface-mount device, compared to that
obtained when using only copper planes on the underside.
REV. 1.0.6 2/14/03
FAN2508/FAN2509
PRODUCT SPECIFICATION
Absolute Maximum Ratings (beyond which the device may be damaged)1
Parameter
Min
Typ
Max
Unit
0
7
V
0
7
V
0
7
V
Power Supply Voltages
VIN (Measured to GND)
Enable Input (EN)
Applied voltage (Measured to GND)2
ERR Output
Applied voltage (Measured to GND)2
Power
Dissipation3
Internally limited
Temperature
Junction
-65
Lead Soldering (5 seconds)
Storage
-65
4
Electrostatic Discharge
150
°C
260
°C
150
°C
4
kV
Notes:
1. Functional operation under any of these conditions is NOT implied. Performance and reliability are guaranteed only
if Operating Conditions are not exceeded.
2. Applied voltage must be current limited to specified range.
3. Based upon thermally limited junction temperature:
T J ( max ) – T A
P D = ------------------------------Θ JA
4. Human Body Model is 4kV minimum using Mil Std. 883E, method 3015.7. Machine Model is 400V minimum using JEDEC
method A115-A.
Recommended Operating Conditions
Parameter
VIN
Min
Input Voltage Range
VOUT
Output Voltage Range, Adjustable
VEN
Enable Input Voltage
VERR
ERR Flag Voltage
Nom
Max
Units
2.7
6.5
V
VREF
VIN-VDO
V
0
VIN
V
VIN
V
+125
°C
TJ
Junction Temperature
θJA
Thermal resistance
220
°C/W
θJC
Thermal resistance
130
°C/W
REV. 1.0.6 2/14/03
-40
5
PRODUCT SPECIFICATION
FAN2508/FAN2509
Electrical Characteristics (Notes 1, 2)
Symbol
Parameter
Conditions
Min.
Typ.
Max.
Units
IOUT = 100 µA
2.5
4
mV
IOUT = 50 mA
50
75
mV
2
%
1.32
1.40
V
6
%
50
µA
1
µA
Regulator
VDO
Drop Out Voltage
∆VO
Output Voltage Accuracy
VDO
Reference Voltage Accuracy, Adjustable
Mode
∆VO3
Output Voltage Accuracy, Adjustable Mode
IGND
Ground Pin Current
-2
1.24
-6
IOUT = 50 mA
Protection
Current Limit
Thermally Protected
IGSD
Shut-Down Current
TSH
Thermal Protection Shutdown Temperature
ETL
ERR Trip Level
EN = 0V
150
FAN2509 only
90
°C
95
99
%
1.2
0.4
V
Enable Input
VIL
Logic Low Voltage
VIH
Logic High Voltage
IIH
Input Current High
1
µA
II
Input Current Low
1
µA
2.0
1.4
V
Switching Characteristics (Notes 1, 2)
Parameter
Conditions
Min.
Typ.
Max.
Unit
500
µsec
3
msec
Enable Input
Response time
Error Flag (FAN2509-XX)
Response time
Performance Characteristics (Notes 1, 2)
Symbol
Parameter
Conditions
∆VOUT/∆VIN
Line regulation
VIN = (VOUT + 1) to 6.5V
0.3
∆VOUT/VOUT
Load regulation
IOUT = 0.1 to 50mA
1.0
eN
Output noise
10Hz–1KHz
COUT = 10µF,
CBYP = 0.01µF
<7
>10KHz,
COUT = 10µF,
CBYP = 0.01µF
<0.01
120 Hz,
COUT = 10µF,
CBYP = 0.01µF
43
PSRR
Power Supply Rejection
Min.
Typ.
Max.
Units
% /V
2.0
%
µV/ Hz
dB
Notes:
1. Unless otherwise stated, TA = 25°C, VIN = VOUT + 1V, IOUT = 100µA, VIH > 2.0 V.
2. Bold values indicate -40 ≤ TJ ≤ 125°C.
3. The adjustable version, has a bandgap voltage range of 1.24V to 1.40V with a nominal value of 1.32V.
4. When using repeated cycling.
6
REV. 1.0.6 2/14/03
FAN2508/FAN2509
PRODUCT SPECIFICATION
Typical Performance Characteristics
Power Supply
Rejection Ratio
Power Supply
Rejection Ratio
100
40
60
40
VIN = 4.0V
VOUT = 3.0V
100
20
Power Supply
Rejection Ratio
Power Supply
Rejection Ratio
40
IOUT = 100µA
COUT = 10µF Cer.
IOUT = 10mA
COUT = 10µF Cer.
40
VIN = 4.0V
VOUT = 3.0V
60
40
20
0
10 100
1k 10k 100k 1M 10M
Frequency (Hz)
0
10
1k 10k 100k 1M 10M
Frequency (Hz)
100
1k 10k 100k 1M 10M
Frequency (Hz)
Noise Performance
Power Supply
Rejection Ratio vs. Voltage Drop
10
70
40
30
COUT = 1.0µF Cer.
50mA
20
50
40
10mA
30
20
3.0
3.6
0
4.1
3.0
Ground Pin Current
19.00
17.00
15.00
0.1
10
1
Load Current (mA)
REV. 1.0.6 2/14/03
0.0001
10
4.1
100
35.00
35.00
30.00
30.00
25.00
20.00
15.00
10.00
5.00
0.00
3.0
VOUT = 3V
IOUT = 100µA
4.0
5.0
6.0
Input Voltage (V)
1k
10k 100k
Frequency (Hz)
1M
Ground Pin Current
Ground Pin Current
Quiescent Current (µA)
21.00
3.6
COUT = 1.0µF
CBYP = 0.01µF
I L = 10µA
Voltage (V)
25.00
VIN = 4V
VOUT = 3V
0.01
COUT = 10µF Cer.
50mA
Voltage (V)
23.00
0.1
0.001
10
10
VIN = 4.0V
VOUT = 3.0V
1
IOUT = 100µA
Quiescent Current (µA)
50
60
10mA
IOUT = 100µA
PSRR (dB)
60
Noise (µV/ Hz)
70
PSRR (dB)
60
IOUT = 50mA
80 COUT = 10µF Cer.
20
Power Supply
Rejection Ratio vs. Voltage Drop
Quiescent Current (µA)
Power Supply
Rejection Ratio
PSRR (dB)
60
1k 10k 100k 1M 10M
Frequency (Hz)
100
VIN = 4.0V
80 VOUT = 3.0V
PSRR (dB)
PSRR (dB)
VIN = 4.0V
80 VOUT = 3.0V
0
10 100
40
0
10 100
1k 10k 100k 1M 10M
Frequency (Hz)
100
20
60
20
0
10 100
1k 10k 100k 1M 10M
Frequency (Hz)
100
0
VIN = 4.0V IOUT = 50mA
80 VOUT = 3.0V COUT = 1.0µF Cer.
PSRR (dB)
60
20
100
VIN = 4.0V IOUT = 10mA
80 VOUT = 3.0V COUT = 1.0µF Cer.
PSRR (dB)
PSRR (dB)
IOUT = 100µA
80 COUT = 1.0µF Cer.
0
10
Power Supply
Rejection Ratio
100
7.0
25.00
20.00
15.00
10.00
VOUT = 3V
IOUT = 50mA
5.00
0.00
3.0
4.0
5.0
6.0
7.0
Input Voltage (V)
7
PRODUCT SPECIFICATION
FAN2508/FAN2509
Typical Performance Characteristics (continued)
75
25
0
-40
0
40
80
Temperature (°C)
50
50.00
VIN = 4V
VOUT = 3V
IL = 50mA
25
0
-40
125
Dropout Voltage (mV)
VIN = 4V
VOUT = 3V
IL = 100µA
Quiescent Current (µA)
Quiescent Current (µA)
50
Dropout Voltage
Ground Pin Current
Ground Pin Current
75
0
40
80
Temperature (°C)
40.00
30.00
20.00
10.00
0.00
0.1
125
10
20
30
40
50
Output Current (mA)
Dropout Characteristics
3.5
Dropout Voltage
3.0
Dropout Voltage
8
100
Dropout Voltage (mV)
Output Voltage (V)
ROUT = 30KΩ
2.0
ROUT = 20Ω
1.5
1.0
0.5
0.0
0.0
1.0
2.0
3.0
4.0
6
4
IL = 100µA
2
0
-40
5.0
Dropout Voltage (mV)
VOUT = 3V
2.5
Input Voltage (V)
0
40
80
Temperature (°C)
75
50
25
0
-40
125
IL = 50mA
0
40
80
Temperature (°C)
125
Output Voltage
vs. Temperature
Output Voltage (V)
3.05
3
2.95
VIN = 4V
Typical 3V device
IL = 100µA
2.9
2.85
-40
0
40
80
Temperature (°C)
125
Functional Characteristics
Enable
Shutdown Delay
Disable Voltage
(1V/div)
Enable Voltage
(1V/div)
Enable Pin Delay
Disable
Output Voltage
(1V/div)
Output Voltage
(1V/div)
VOUT
Time (20µs/div)
8
VOUT
Time (20µs/div)
REV. 1.0.6 2/14/03
FAN2508/FAN2509
PRODUCT SPECIFICATION
Mechanical Dimensions
5-Lead SOT-23-5 (S) Package
Inches
Symbol
A
A1
B
c
D
E
e
e1
H
L
α
Millimeters
Min.
Max.
Min.
Max.
.035
.000
.008
.003
.106
.059
.057
.006
.90
.00
.20
.08
2.70
1.50
1.45
.15
.020
.010
.122
.071
.037 BSC
.075 BSC
.087
.126
.004
.024
0°
10°
Notes:
Notes
1. Package outline exclusive of mold flash & metal burr.
2. Package outline exclusive of solder plating.
3. EIAJ Ref Number SC-74A.
.50
.25
3.10
1.80
.95 BSC
1.90 BSC
2.20
3.20
.10
.60
0°
10°
e
B
L
E
H
e1
c
D
A
A1
REV. 1.0.6 2/14/03
9
PRODUCT SPECIFICATION
FAN2508/FAN2509
Ordering Information
Product Number
VOUT
Pin 4 Function
Package Marking
FAN2508SX
FAN2508S25X
Adj.
Adjust
AAA
2.5
Bypass
AAE
FAN2508S26X
2.6
Bypass
AAG
FAN2508S27X
2.7
Bypass
AAJ
FAN2508S28X
2.8
Bypass
AAM
FAN2508S285X
2.85
Bypass
AAN
FAN2508S30X
3.0
Bypass
AAW
FAN2508S33X
3.3
Bypass
AA3
FAN2509S25X
2.5
Error output
ABE
FAN2509S26X
2.6
Error output
ABG
FAN2509S27X
2.7
Error output
ABJ
FAN2509S28X
2.8
Error output
ABM
FAN2509S285X
2.85
Error output
ABN
FAN2509S30X
3.0
Error output
ABW
FAN2509S33X
3.3
Error output
AB3
Tape and Reel Information
Quantity
Reel Size
Width
3000
7"
8mm
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device or system, or to affect its safety or effectiveness.
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 2000 Fairchild Semiconductor Corporation
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