FAIRCHILD FAN2535

www.fairchildsemi.com
FAN2534/FAN2535
150 mA CMOS LDO Regulator with Fast Start, Enable
Features
•
•
•
•
•
•
•
•
•
•
•
70dB Ripple rejection ( >45dB up to 1MHz)
150µsec Power On Time
150µsec Enable Time
Low noise - 50µVrms
Enable optimized for CDMA time slices
180 mV dropout voltage at 150 mA
Enable/Shutdown Control
Enable time independent of noise bypass capacitor value
SOT23-5 package
Thermal limiting
300 mA trimmed current limit
Applications
•
•
•
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low dropout voltage, fast enable required in CDMA handset
applications, exceptional loop stability to accommodate a
wide variety of external capacitors, and a compact SOT23-5
surface-mount package. These products offer significant
improvements over older Bipolar and CMOS designs and are
pin-compatible with many popular devices.
The FAN2534 and FAN2535 devices are distinguished by
the assignment of pin 4:
FAN2534: pin 4 – ADJ, allowing the user to adjust the
output voltage over a wide range using an external voltage
divider.
FAN2534-XX: pin 4 – BYP, to which a bypass capacitor
may be connected for optimal noise performance. Output
voltage is fixed, as specified by the suffix XX.
Cellular Phones and accessories
PDAs
Portable cameras and video recorders
Laptop, notebook and palmtop computers
FAN2535-XX: pin 4 – ERR, a flag which indicates that the
output voltage has dropped below the specified minimum
due to a fault condition.
Description
The FAN2534/FAN2535 family of micropower low-dropout
voltage regulators utilize CMOS technology to offer a new
level of cost-effective performance in GSM, TDMA, and
CDMA cellular handsets, laptop and notebook computers,
and other portable devices. Proprietary design technics
ensure high ripple rejection. Other features include low
noise, short circuit current limit, thermal shutdown circuit,
The standard fixed output voltages available are 2.6V, 2.85V,
and 3.0V . Custom output voltages are also available: please
contact your local Fairchild Sales Office for information.
Block Diagrams
EN
EN
EN
VIN
VIN
BYP
Bandgap
Error
Amplifier
Bandgap
p
VOUT
Error
Amplifier
VIN
Bandgap
p
ERR
Error
Amplifier
p
VOUT
VOUT
ADJ
Thermal
Sense
FAN2534
Thermal
Sense
GND
FAN2534-XX
Thermal
Sense
GND
GND
FAN2535-XX
REV. 1.0.2 8/26/03
FAN2534/FAN2535
PRODUCT SPECIFICATION
Pin Assignments
VIN
1 FB
5
VOUT
4
ADJ/BYP/ERR
SHDN
GND
2
CAP+
EN 3
CAP-
Pin No.
FAN2534
FAN2534-XX
FAN2535-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
FAN2534 Adjust. Ratio of potential divider from VOUT to ADJ
determines output voltage.
BYP
4
Passive
FAN2534-XX Bypass. Connect 10 nF capacitor for noise reduction.
ERR
4
Open drain
FAN2535-XX Error. Error flag output.
LOW when Vout< 95% of nominal; HIGH when Vout> 95% of nominal.
EN
3
Digital Input
Enable.
LOW in Shutdown Mode; HIGH in Enable Mode
VIN
1
Power in
Voltage Input. Supply voltage input.
VOUT
5
Power out
Voltage Output. Regulated output voltage.
GND
2
Power
Ground.
Absolute Maximum Ratings (Note 1)
Parameter
Min.
Typ.
Max.
Unit
7
V
Power Supply Voltages
VIN (Measured to GND); Enable Input (EN);
ERR Output;
0
Power Dissipation
Operating Junction Temperature
Internally limited
-65
Lead Soldering (5 seconds)
Storage
Electrostatic Discharge (Note 2)
2
-65
4
150
°C
260
°C
150
°C
kV
REV. 1.0.2 8/26/03
PRODUCT SPECIFICATION
FAN2534/FAN2535
Operating Conditions
Symbol
Parameter
VIN
Min.
Input Voltage Range
Typ.
Max.
Units
VOUT+VDO
6.5
V
VOUT
Output Voltage Range
FAN2534-XX, FAN2535-XX (Note 3)
2.3
3.3
V
VOUT
Output Voltage Range (FAN2534 only)
2.0
5.0
V
VEN
Enable Input Voltage
0
VIN
V
VERR
ERR Flag Voltage
VIN
V
-40
+125
°C
TJ
Junction Temperature
θJA
Thermal resistance
220
°C/W
θJC
Thermal resistance
130
°C/W
DC Electrical Characteristics (Notes 4, 5)
Symbol
Parameter
Conditions
Min.
Typ.
Max.
Units
Regulator
VDO
∆VO
Drop Out Voltage (Note 6)
Output Voltage Accuracy
(Note 7)
IOUT = 100 µA
2.5
4
mV
IOUT = 50 mA
50
75
mV
IOUT = 100 mA
100
140
mV
IOUT = 150 mA
180
220
mV
-1
1
%
-3.7
2
%
Initial Accuracy at no
load
Over Line, Load &
Temp
IGND(NL) Ground Pin Current
No Load
90
µA
IGND(FL)
IOUT = 150 mA
110
µA
Ground Pin Current
Protection
Current Limit
IGSD
Shut-Down Current
TSH
Thermal Shutdown
Temperature
Hysteresis
ETL
ERR Trip Level
300
EN = 0V
FAN2535 only
90
400
mA
1
µA
155
°C
15
°C
93
96
%
0.4
1.2
V
Enable Input
VEL
Logic Low Voltage
VEH
Logic High Voltage
IEH
Input Current High
1
µA
IEL
Input Current Low
1
µA
REV. 1.0.2 8/26/03
1.4
2
V
3
FAN2534/FAN2535
PRODUCT SPECIFICATION
Switching Characteristics (Notes 4, 5)
Parameter
Conditions
Min.
Typ.
Max.
Unit
Enable Response time (Note 8)
CL=10µF CBP=10nF
150
300
µsec
Power "ON" Response time
CL=10uF CBP=10nF
VOUT = 3.0V
150
500
µsec
3
msec
Typ.
Max.
Units
Error Flag Response time
(FAN2535-XX only)
AC Performance Characteristics (Notes 4, 5)
Symbol
Parameter
Conditions
Min.
∆VOUT/
∆VIN
Line regulation
VIN = (VOUT + 1) to 6.5V, IL = 10mA
0.05
0.2
% /V
∆VOUT/
VOUT
Load regulation
IOUT = 0.1 to 100mA
1.0
2.0
%
eN
Output noise
BW: 300Hz–50KHz
COUT = 10µF,
CBYP = 0.01µF
50
µVRMS
PSRR
Power Supply
Ripple Rejection
100 Hz,
COUT = 1µF,
CBYP = 0.01µF
0mA<IL<150mA
70
dB
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. Using Mil Std. 883E, method 3015.7(Human Body Model), 400V when using JEDEC method A115-A (Machine Model).
3. For specific output voltages of the fixed oputput voltage versions please refer to the table: "Output Voltage Options and
Ordering Information" on Page 9. Custom fixed output voltages, not listed in the table, are also available.
4. Unless otherwise stated, TA = 25°C, VIN = VOUT + 1V, IOUT = 100µA, VEH > 2.0 V.
5. Bold values indicate -40 <TJ <125°C.
6. Dropout Voltage is defined as the input to output differential at which the output voltage drops to 2% below the nominal value
measured at 1V input - output differential.
7. Adjustable version, has a bandgap reference voltage of 1.0V, trimmed to +/-1% initial accuracy.
8. When using repeated cycling, F>0.5Hz.
4
REV. 1.0.2 8/26/03
PRODUCT SPECIFICATION
FAN2534/FAN2535
Functional Description
Applications Information
Utilizing CMOS technology, the FAN2534/FAN2535
product family is optimized for use in compact battery
powered systems, offering a unique combination of high
ripple rejection, low noise, low power consumption,
extremely low dropout voltages, high tolerance for a variety
of output capacitors, and less than 1µA "OFF" current.
In the circuit, a differential amplifier controls a series-pass
P-Channel MOSFET, and a separate error amplifier compares the load voltage at the output with an onboard trimmed
low voltage bandgap reference. The series resistance of the
pass P-Channel MOSFET is approximately 1 Ohm, yielding
an unusually low dropout voltage even under high load
conditions.
External Capacitors – Selection
Thermal shutdown and current limit circuits protect the
device under extreme conditions. When the device temperature reaches 155°C, the output is disabled, until the device
cooles down by 15°C, then re-enabled. The user can to shut
down the device using the Enable control pin at any time.
The current limit circuit is trimmed, which leads to consistent power on /enable delays, and provides safe short circuit
current densities even in narrow traces of the PCB.
An input capacitor of 2.2µF (nominal value) or greater,
connected between the Input pin and Ground, placed in close
proximity to the device, will improve transient response and
ripple rejection. Higher values will further improve 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 in extreme cases
capacitor surge current ratings may have to be considered.
A carefully optimized control loop accommodates a wide
range of ESR values in the output bypass capacitor, allowing
the user to optimize space, cost, and performance requirements.
An Enable pin shuts down the regulator output to conserve
power, reducing supply current to less than 1µA. The output
can then be re-Enabled within 150µSec, fulfilling the fast
power-cycling needs of CDMA applications.
Depending on the device type selected, other control and
status functions are available at pin 4. The fixed-voltage
versions are available with either a noise-bypass pin or an
Error flag pin option. The error flag can be used as a diagnostic function to indicate that the output voltage has dropped
more than 5% below the nominal value.
The adjustable-voltage versions utilize pin 4 to connect to an
external voltage divider which feeds back to the regulator
error amplifier, thus setting the output voltage to the desired
value.
REV. 1.0.2 8/26/03
The FAN2534/FAN2535 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 (Equivalent Series Resistance), which
degrades regulator loop stability in older designs. While the
improvements featured in the FAN2534/FAN2535 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, and a smaller case size than tantalums.
Input Capacitor
Output Capacitor
An output capacitor is required to maintain regulator loop
stability. Stable operation will be achieved with a wide
variety of capacitors with ESR values ranging from 0mΩ
up to 400mΩ. Multilayer ceramic, tantalum or aluminum
electrolytic capacitors may be used. A nominal value of at
least 1µF is recommended. Note that the choice of output
capacitor effects load transient response, ripple rejection,
and it has a slight effect on noise performance as well.
Bypass Capacitor (FAN2534-XX Only)
In the fixed-voltage configuration, connecting a capacitor
between the bypass pin and ground can significantly reduce
output noise. Values ranging from 0pF to 47nF 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
PCB 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.
5
FAN2534/FAN2535
Control Functions
Enable Pin
Connecting 2.0V or greater to the Enable pin will enable the
output, while 0.4V or less will disable it while reducing the
quiescent current consumption to less than 1µA. If this
shutdown function is not needed, the pin can simply be
connected permanently to the VIN pin. Allowing this pin
to float will cause erratic operation.
Error Flag (FAN2535-XX Only)
Fault conditions such as input voltage dropout
(low VIN), overheating, or overloading (excessive output
current), will set an error flag: The ERR pin which is an
open-drain output, will go LOW when VOUT is less than
95% or the specified output voltage. When the voltage at
VOUT is greater than 95% of the specified output voltage,
the ERR pin is HIGH. A logic pullup resistor of 100K Ohm
is recommended at this output. The pin can be left disconnected if unused.
Thermal Protection
The FAN2534/FAN2535 is designed to supply high peak
output currents for brief periods, however sustained excessive output load at high input - output voltage difference
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 155°C, an onboard thermal
protection will disable the output until the temperature drops
approximately 15°C below the limit, at which point the
output is re-enabled. During a thermal shutdown situation
the user may assert the power-down function at the Enable
pin, reducing power consumption to a minimum.
Thermal Characteristics
The FAN2534/FAN2535 is designed to supply 150mA 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
actual thermal resistance depends on the thermal characteristics of the 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
PRODUCT SPECIFICATION
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 thermal resistance.
The heat contributed by the dissipation of other devices
located nearby must be included in the 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 the device to enter a thermal cycling loop, in
which the circuit enters a shutdown condition, cools, reenables, and then again overheats and shuts down repeatedly
due to an unmanaged fault condition.
Adjustable Version
The FAN2534 adjustable version includes an input pin ADJ
which allows the user to select an output voltage ranging
from 2.5V 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
1.00V(typ). The equation is:
R upper
V OUT = 1.00V × 1 + ---------------R lower
Since the bandgap reference voltage is trimmed, 1% initial
accuracy can be achieved. The total value of the resistor
chain should not exceed 250K Ohm 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.
The ground pin current IGND can be found in the charts
provided in the Electrical Characteristics section.
6
REV. 1.0.2 8/26/03
PRODUCT SPECIFICATION
FAN2534/FAN2535
General PWB Layout Considerations
For optimum device performance, careful circuit layout and
grounding technics must be used. Establishing a small local
ground, to which the GND pin, and 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 optimum performance, especially
during high load conditions. A large copper area in the local
ground serves as heat sink (as discussed above) when high
power dissipation significantly increases device temperature.
Component-side copper provides significantly better thermal
performance. Added feedthrough connecting the device side
ground plane to the back plane further reduces thermal
resistance.
REV. 1.0.2 8/26/03
7
FAN2534/FAN2535
PRODUCT SPECIFICATION
Typical Performance Characteristics
Enable Delay
Disable Delay
VEN
VEN
C out = 3.3µF, C byp = 10nF,
I load = 150mA
Disable Delay = 214µSec
C out = 3.3µF, C byp = 10nF,
I load = 150mA
Enable Delay = 152µSec
VOUT
VOUT
Ground Current vs
Ambient Temperature
Power on Delay
110
ILOAD = 0mA
C out = 3.3µF, C byp = 10nF, ILOAD = 150mA
Power on Delay = 150µSec
VOUT
Ground Current (µA)
VIN
100
90
80
70
-40
-20
0
20
40
60
80
100
120
Ambient Temperature (°C)
Ripple Rejection Plot
Noise Plot
1.8µV
-30
dB
-35
1.6µV
-40
1.4µV
1.2µV
Cout = 3.3µF, Cbyp = 10nF
Iload = 150mA
Cout = 3.3µF, Cbyp = 10nF
Iload = 150mA
-45
-50
1µV
-55
800nV
-60
600nV
-65
400nV
-70
-75
200nV
8
-80
REV. 1.0.2 8/26/03
PRODUCT SPECIFICATION
FAN2534/FAN2535
Typical Performance Characteristics (Continued)
Dropout Voltage vs
Ambient Temperature
0.6
240
0.4
220
Droupout Voltage (mV)
VOUT Variation (%)
VOUT Variation vs
Ambient Temperature
0.2
Iload = 150mA
0.0
-0.2
-0.4
-0.6
-0.8
-25
0
25
50
Ambient Temperature (°C)
75
Iload = 150mA
200
180
160
140
120
-40
-20
0
20
40
Ambient Temperature (°C)
60
Dropout Voltage vs
Load Current
160
Droupout Voltage (mV)
140
T = 25°C
120
100
80
60
40
20
0
0
25
REV. 1.0.2 8/26/03
50
75
100
Load Current (mA)
125
150
9
FAN2534/FAN2535
PRODUCT SPECIFICATION
Mechanical Dimensions
5-Lead SOT-23 Package
Symbol
B
e
e1
D
A
A1
10
Millimeters
Min
Max
Min
Max
A
.035
.057
.90
1.45
A1
.000
.006
.00
.15
B
.008
.020
.20
.50
c
.003
.010
.08
.25
D
.106
.122
2.70
3.10
E
.059
.071
1.50
1.80
c
L
H
α
E
Inches
e
.037 BSC
.95 BSC
e1
.075 BSC
1.90 BSC
H
.087
.126
2.20
3.20
L
.004
.024
.10
.60
α
0°
10°
0°
10°
Notes
REV. 1.0.2 8/26/03
PRODUCT SPECIFICATION
FAN2534/FAN2535
Output Voltage Options and Ordering Information
Product Number
VOUT
Pin 4 Function
Package Marking
FAN2534SX
Adj.
Adjust
AJA
FAN2534S26X
2.6
Bypass
AJG
FAN2534S30X
3.0
Bypass
AJW
FAN2535S26X
2.6
Error output
AKG
FAN2535S285X
2.85
Error output
AKN
Tape and Reel Information
Quantity
Reel Size
Width
3000
7"
8mm
DISCLAIMER
FAIRCHILD SEMICONDUCTOR RESERVES THE RIGHT TO MAKE CHANGES WITHOUT FURTHER NOTICE TO
ANY PRODUCTS HEREIN TO IMPROVE RELIABILITY, FUNCTION OR DESIGN. FAIRCHILD DOES NOT ASSUME
ANY LIABILITY ARISING OUT OF THE APPLICATION OR USE OF ANY PRODUCT OR CIRCUIT DESCRIBED HEREIN;
NEITHER DOES IT CONVEY ANY LICENSE UNDER ITS PATENT RIGHTS, NOR THE RIGHTS OF OTHERS.
LIFE SUPPORT POLICY
FAIRCHILD’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES
OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT OF FAIRCHILD SEMICONDUCTOR
CORPORATION. As used herein:
1. Life support devices or systems are devices or systems
which, (a) are intended for surgical implant into the body, or
(b) support or sustain life, and (c) whose failure to perform
when properly used in accordance with instructions for use
provided in the labeling, can be reasonably expected to
result in a significant injury of the user.
2. A critical component in any component of a life support
device or system whose failure to perform can be
reasonably expected to cause the failure of the life support
device or system, or to affect its safety or effectiveness.
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