SPX2954U3-L-5.0 [EXAR]
Fixed Positive LDO Regulator, 5V, 0.6V Dropout, PSFM3, TO-220, 3 PIN;
| 型号： | SPX2954U3-L-5.0 |
| 厂家： | 
EXAR CORPORATION |
| 描述： | Fixed Positive LDO Regulator, 5V, 0.6V Dropout, PSFM3, TO-220, 3 PIN |
| 文件： | 总7页 (文件大小：206K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
SPX2954
250 mA Low Drop Out Voltage Regulator
FEATURES
APPLICATIONS
• Output Accuracy 5V, 3.3V,@ 250mA Output
• Very Low Quiescent Current
• Battery Powered Systems
• Cordless Telephones
• Low Dropout Voltage
• Radio Control Systems
• Portable/Palm Top/Notebook Computers
• Portable Consumer Equipment
• Portable Instrumentation
• Automotive Electronics
• SMPS Post-Regulator
• Extremely Tight Load And Line Regulation
• Very Low Temperature Coefficient
• Current & Thermal Limiting
• Improved Replacement With Hight IOUT For LP2954 Sockets
• Voltage Reference
• Avionics
SPX2954 Version Over LP2954
• Error Flag Warns Of Output Dropout
• Logic-Controlled Electronic Shutdown
• Output Programmable From 1.24V to 29V
• Input Can Withstand -20V Reverse Battery & +60 Positive Transient
PRODUCT DESCRIPTION
The SPX2954 is a low power voltage regulator. This device is an excellent choice for use in battery-powered applications such as
cordless telephones, radio control systems, and portable computers. The SPX2954 features very low quiescent current (75µA Typ.)
and very low dropout voltage. This includes a tight initial tolerance of 0.5% max and 1% max., and very low output temperature
coefficient, making the SPX2954 useful as a low-power voltage reference. The key SPX2954 features include protection against
reversed battery, fold-back current limiting, and automotive load dump protection (60V positive transient).
The error flag output feature is used as power-on reset for warning of a low output voltage, due to falling voltage input of batteries.
Another feature is the logic compatible shutdown input which enables the regulator to be switched on and off. The SPX2954 is offered
in a 3-pin TO-92and TO-263 package compatible with other 5 volt regulators, in 8-Pin plastic, SO-8, (same pin out as SPX2951), TO-
220 and TO-263.
The regulator output voltage (of the 8-pin) may be pin-strapped for a 5Vand 3.3V or programmed from 1.24V to 29V with an external
pair of resistors. Look for SPX2951 for 150mA and LP2951 for 100mA applications.
PIN CONNECTIONS
TO-263-3 Package
SPX2954
TO-263-5 Package
SPX2954
8-Pin Surface Mount (S)
TO-220-3 Package
SPX2954
TO-220-5 Packa
SOT-223 Package
INPUT
OUTPUT
1
2
3
4
8
7
6
5
SENSE
FEEDBACK
5V, 3.3V TAP
ERROR
SPX2954
SPX2954
SHUTDOWN
GND
SPX2954
1
2
3
1
2
3
1
2
3
4
5
1)
INPUT
1)
INPUT
2) OUTPUT
OUTPUT
GND
2)
3)
4)
5)
3)
4)
5)
GND
SHUTDOWN
ERROR
GND
V
V
Top View
TO-92 (N)
IN
OUT
SHUTDOWN
ERROR
Front View
V
VIN
VOUT
ADJ
1
VIN
2
3
V
1
2
3 4
5
2
1
3
Top View
Top View
GND
OUT
Front View
Front View
OUTPUT
INPUT
GND
Bottom View
Rev. 11/21/00
SPX2954
ABSOLUTE MAXIMUM RATINGS
Power Dissipation..........................................Internally Limited
Lead Temp. (Soldering, 5 Seconds) ................................ 260°C
Storage Temperature Range ............................-65° to +150°C
Operating Junction Temperature Range (Note 9)
Input Supply Voltage .......................................-20V to +60V
Feedback Input Voltage .....................................-1.5 to +30V
Shutdown Input Voltage.....................................-0.3 to +30V
Error Comparator Output...................................-0.3 to +30V
ESD Rating ............................................................2KV Min
SPX2954................................................ -40C° to +125°C
ELECTRICAL CHARACTERISTICS at VS=±15V, TA=25°C, unless otherwise noted.
applies over the full
Boldface
operating temperature range.
Parameter
Conditions
Typical
SPX2954A
SPX2954
Units
Min
Max
3.317
3.333
3.340
Min
Max
3.333
3.350
3.366
Output Voltage
3.3
3.284
3.267
3.260
3.267
3.251
3.234
V
T =25 C
°
≤
J
-25 C
T
J
+85 C
≤ °
°
-40 C TJ +125 C
°
≤
≤
°
Output Voltage
Output Voltage
V
V
3.3
3.251
3.350
3.201
3.399
1mA
I
250mA
≤
≤
L
TJ
T
JMAX
≤
5.0
5.0
5.0
4.975
4.95
4.94
5.025
5.050
5.06
4.95
4.925
4.90
5.05
5.075
5.10
T =25 C
°
≤
≤
J
-25 C
T
J
+85 C
≤ °
°
°
-40 C TJ +125 C
≤
°
Output Voltage
V
5.0
4.925
5.075
4.85
5.15
1mA
I
250mA
≤
≤
L
TJ
T
JMAX
≤
Output Voltage
Temperature Coefficient
Line Regulation (Note 3)
20
0.03
0.04
60
ppm/°C
%max
%max
mV
100
150
(Note 1)
6V
0.10
0.20
0.16
0.20
100
150
250
420
300
450
450
600
150
180
2
0.20
0.40
0.20
0.30
100
150
250
420
300
450
450
600
150
180
2
V
30V (Note 4)
≤
≤
IN
Load Regulation (Note 3)
IL = 1 to 250 mA
IL = 0.1 to 1 mA
IL = 1mA
Dropout Voltage
(Note 5)
IL = 50mA
IL= 100mA
IL= 250 mA
IL = 1mA
220
250
375
90
Ground Current
Current Limit
A
µ
IL = 50mA
IL = 100mA
IL = 250 mA
VOUT = 0
1
mA
2.5
6
2.5
6
4.5
21
8
8
14
20
16
22
550
600
0.2
550
600
0.2
mA
Thermal Regulation
Output Noise,
10Hz to 100khz
0.05
400
%/w
V rms
µ
C = 2.2 F
µ
L
IL = 100mA
260
Typical
1.235
C = 33
L
F
µ
8-Pin Versions only
Reference Voltage
SPX2954A
SPX2954
1.220
1.200
1.190
1.250
1.260
1.27
40
60
1.210
1.200
1.185
1.260
1.270
1.285
V
Reference Voltage
Feedback Pin Bias Current
Over Temperature (Note 6)
(Note 7)
V
20
40
60
nA
Reference Voltage Temperature
Coefficient
Feedback Pin Bias Current
Temperature Coefficient
ppm/°C
nA/°C
50
0.1
Rev. 11/21/00
SPX2954
(Continued)
Parameter
Conditions
Typical
SPX2954A
SPX2954
Units
(Note 2)
Min
Max
Min
Max
Applies for SPX2954YT5-X, SPX2954YU5-X and SPX2954YS-X
Error Comparator
Output Leakage Current
V
OH = 30V
0.01
150
100
2.00
250
400
100
2.00
250
400
A
µ
Output Low Voltage
VIN = 4.5V
mV
IOL = 400 A
µ
Upper Threshold Voltage
Lower Threshold Voltage
Hysteresis
(Note 8)
(Note 8)
(Note 8)
240
350
60
-320
-380
-450
-640
-150
-100
230
-320
-380
-450
-640
-150
-100
230
mV
mV
mV
160
160
Shutdown Input
VSD
Output Turn-On
Threshold Voltage
1.155
1.140
1.305
1.320
1.155
1.140
1.305
1.320
V
mV
Hysteresis(HYST)
6
Input Bias Current(IB)
VIN(SD) = 0V to 5V
10
-30
-50
-30
-50
-30
-50
-30
-50
nA
Note 1: Output or reference voltage temperature coefficients defined as the worst case voltage change divided by the total temperature range.
Note 2: Unless otherwise specified all limits are guaranteed for TJ = 25°C, VIN = 6V, IL = 100 µA and CL = 1µF. Additional conditions for the 8-pin versions are
feedback tied to 5V tap and output tied to output sense (VOUT = 5V) and VSHUTDOWN ≤ 0.8V.
Note 3: Regulation is measured at constant junction temperature, using pulse testing with a low duty cycle. Changes in output voltage due to heating effects are
covered under the specification for thermal regulation.
Note 4: Line regulation for the SPX2954 is tested at 150°C for IL = 1 mA. For IL = 100µA and TJ = 125°C, line regulation is guaranteed by design to 0.2%. See
typical performance characteristics for line regulation versus temperature and load current.
Note 5: Dropout voltage is defined as the input to output differential at which the output voltage drops 100 mV below its nominal value measured at 1V differential at
very low values of programmed output voltage, the minimum input supply voltage of 2V (2.3V over temperature) must be taken into account.
Note 6: VREF ≤VOUT ≤ (VIN - 1V), 2.3 ≤VIN≤30V, 100µA≤IL≤ 250 mA, TJ ≤ TJMAX
.
Note 7: Comparator thresholds are expressed in terms of a voltage differential at the feedback terminal below the nominal reference voltage measured at 6V input. To
express these thresholds in terms of output voltage change, multiply by the error amplifier gain = VOUT/VREF = (R1 + R2)/R2. For example, at a programmed output
voltage of 5V, the ERROR output is guaranteed to go low when the output drops by 95 mV x 5V/1.235 = 384 mV. Thresholds remain constant as a percent of VOUT as
V
OUT is varied, with the dropout warning occurring at typically 5% below nominal, 7.5% guaranteed.
Note 8: VSHUTDOWN ≥ 2V, VIN ≤ 30V, VOUT =0, feedback pin tied to 5V Tap.
Note 9: The junction -to-ambient thermal resistance of the TO-92 package is 180°C/ W with 0.4” leads and 160°C/ W with 0.25” leads to a PC board.
The thermal resistance of the 8-Pin DIP package is 105°C/W junction-to-ambient when soldered directly to a PC board. Junction-to-ambient thermal resistance for the
SOIC (S) package is 160°C/W.
UNREGULATED DC
VO
5V @ 250mA
1
7
8
MAX
+
INPUT
FEEDBACK
OUTPUT
2
SENSE
Ω
180k
..
+
_
6
ERROR
3
FROM
CMOS OR
TTL
AMPLIFIER
Ω
5V TAP
330k ..
SHUTDOWN
+
Ω
60k ..
5
µ
1
F..
+
______
ERROR
+
_
60 mV
ERROR
TO CMOS OR
TTL
COMPARATOR
+
1.23V
4
REFERENCE
GROUND
SPX2954 Block Diagram
Rev. 11/21/00
SPX2954
APPLICATION HINTS
EXTERNAL CAPACITORS
This problem can be fixed by adding a 100pF capacitor between
output and feedback and increasing the output capacitor to at least
3.3µF.
For the stability of the SPX2954 requires a 2.2µF or greater
capacitor between output and ground. Oscillation could occur
without this capacitor. Most types of tantalum or aluminum
electrolytic works fine here. For operations of below -25°C solid
tantalum is recommended since the many aluminum types have
electrolytes the freeze at about -30°C. The ESR of about 5Ω or
less and resonant frequency above 500kHz are the most
important parameters in the value of the capacitor. The capacitor
value can be increased without limit.
ERROR DETECTION COMPARATOR OUTPUT
The Comparator produces a logic low output whenever the SPX2954
output falls out of regulation by more than around 5%. This is around
60mV offset divided by the 1.235 reference voltage. This trip level
remains 5% below normal regardless of the programmed output
voltage of the regulator. Figure 1 shows the timing diagram depicting
the ERROR signal and the regulator output voltage as the SPX2954
input is ramped up and down. The ERROR signal becomes low at
around 1.3V input, and goes high around 5V input (input voltage at
which VOUT = 4.75. Since the SPX2954’s dropout voltage is load
dependent, the input voltage trip point (around 5V) will vary with the
load current. The output voltage trip point (approx. 4.75V) does not
vary with load.
At lower values of output current, less output capacitance is
required for stability. For the currents below 10mA the value of
the capacitor can be reduced to 0.5µF and 0.15µF for 1mA.
More output capacitance needed for the 8-pin version at voltages
below 5V since it runs the error amplifier at lower gain. At worst
case 5µF or greater must be used for the condition of 250mA
load at 1.23V output.
The error comparator has an open-collector output, which requires an
external pull-up resistor. Depending on the system requirements the
resistor may be returned to 5V output or other supply voltage. In
determining the value of this resistor, note that the output is rated to
sink 400µA, this value adds to battery drain in a low battery
condition. Suggested values range from 100K to 1MΩ. If the output
is unused this resistor is not required.
The SPX2954, unlike other low dropout regulators will remain
stable and in regulation with no load in addition to the internal
voltage divider.
This feature is especially important in
application like CMOS RAM keep-alive. When setting the
output voltage of the SPX2954, a minimum load of 1µA is
recommended
If there is more than 10 inches of wire between the input and the
AC filter capacitor or if a battery is used as the input then a 1µA
tantalum or aluminum electrolytic capacitor should be placed
from the input to the ground.
PROGRAMMING THE OUTPUT VOLTAGE OF
SPX2954
The SPX2954 may be pin-strapped for 5V using its internal voltage
divider by tying Pin 1 (output) to Pin 2 (sense) and Pin 7 (feedback)
to Pin 6 (5V Tap).
Instability can occur if there is stray capacitance to the SPX2954
feedback terminal (pin 7). This could cause more problems when
using a higher value of external resistors to set the output voltage.
+VIN
4.75V
8
100K
OUTPUT
+VIN
______
ERROR
5
VOLTAGE
ERROR
1.2 to 30V
1
OUTPUT
VOUT
_______
ERROR*
SPX2954
+
R1
SHUTDOWN
INPUT
3
3.3uF
SD
.01uF
FB
GND
7
4
+
5.0V
+
1.23V
V REF
INPUT
+
1.3V
VOLTAGE
+
R2
* See Application Info
.
_______
Figure 1. ERROR Output Timing
Figure 2. Adjustable Regulator
Rev. 11/21/00
SPX2954
Also, it may be programmed for any output voltage between its
1.235V reference and its 30V maximum rating. As seen in
Figure 2, an external pair of resistors is required.
Refer to the below equation for the programming of the output
voltage:
REDUCING OUTPUT NOISE
It may be an advantage to reduce the AC noise present at the output.
One way is to reduce the regulator bandwidth by increasing the size of
the output capacitor. This is the only way that noise can be reduced
on the 3 lead SPX2954 but is relatively inefficient, as increasing the
capacitor from 1µF to 220µF only decreases the noise from 430µV to
160µV rms for a 100kHz bandwidth at 5V output.
V
OUT = VREF × ( 1 + R1\ R2 )+ IFBR1
Noise could also be reduced fourfold by a bypass capacitor across R1,
since it reduces the high frequency gain from 4 to unity. Pick
The VREF is 1.235 and IFB is the feedback bias current, nominally
-20nA. The minimum recommended load current of 1µA forces
an upper limit of 1.2 MΩ on value of R2. If no load is presented
the IFB produces an error of typically 2% in VOUT, which may be
eliminated at room temperature by trimming R1. To improve the
accuracy choose the value of R2 = 100k this reduces the error by
0.17% and increases the resistor program current by 12µA. Since
the LP2951 typically draws 60µA at no load with Pin 2 open-
circuited this is a small price to pay
C
BYPASS ≅ 1 / 2πR1 × 200 Hz
or choose 0.01µF. When doing this, the output capacitor must be
increased to 3.3µF to maintain stability. These changes reduce the
output noise from 430µV to 100µVRMS for a 100kHz bandwidth at 5V
output. With the bypass capacitor added, noise no longer scales with
output voltage so that improvements are more dramatic at higher
output voltages.
HEATSINK REQUIREMENTS
Depending on the maximum ambient temperature and maximum
power dissipation a heatsink may be required with the SPX2954.
The junction temperature range has to be within the range
specified under Absolute Maximum Ratings under all possible
operating conditions. To find out if a heatsink is required, the
maximum power dissipation of the device needs to be calculated.
This is the maximum specific AC voltage that must be taken into
consideration at input. Figure 3 shows the condition and power
dissipation which should be calculated with the following
formula:
IIN
5V
IN
VIN
OUT
IL
P
TOTAL = (VIN - 5) IL + (VIN)IG
SPX2954
LOAD
Next step is to calculate the temperature rise TR (MAX). TJ (MAX
)
+
+
maximum allowable junction temperature, TA
ambient temperature :
(MAX) maximum
2.2 uF
GND
TR (MAX) = TJ (MAX) - TA (MAX
)
IG
IIN= IL+ IG
Junction to ambient thermal resistance θ(j-A) can be calculated
after determining of PTOTAL & TR (MAX):
Figure 3. 5V Regulator Circuit
θ(J-A) = TR (max)/P(MAX)
If the θ(J-A) is 60°C/W or higher, the device could be operated
without a heatsink. If the value is below 60°C/W then the
heatsink is required and the thermal resistance of the heatsink can
be calculated by the following formula, θ(J-C) junction to case,
θ(C-H) case to heatsink, θ(H-A) heatsink to ambient:
θ(J-A) = θ(J-C) + θ(C-H) + θ(H-A)
Rev. 11/21/00
SPX2954
TYPICAL APPLICATIONS
+VIN
8
+VIN
______
ERROR
5
ERROR
*VOUT = VIN
1
OUTPUT
VOUT
SPX2954
3
SHUTDOWN
INPUT
SD
FB
GND
4
7
*
MINIMUM INPUT-OUTPUT VOLTAGE RANGES FROM 4mV TO 400mV.
DEPENDING ON LOAD CURRENT. CURRENT LIMIT IS TYPICALLY 160mA
Wide Input Voltage Range Current Limited
+V IN
+V IN
*V OUT = 5V
VOUT
SPX2954
+
10uF
GND
4
SPX2954 FIXED +5V REGULATOR
Rev. 11/21/00
SPX2954
ORDERING INFORMATION
Precision Output Voltage
Ordering No.
SPX2954T3-3.3
SPX2954T3-5.0
SPX2954AT3-3.3
SPX2954AT3-5.0
SPX2954T5-3.3
SPX2954T5-5.0
SPX2954AT5-3.3
SPX2954AT5-5.0
SPX2954N-3.3
Packages
3 Lead TO-263
3 Lead TO-263
3 Lead TO-263
3 Lead TO-263
5 Lead TO-263
5 Lead TO-263
5 Lead TO-263
5 Lead TO-263
3 Lead TO-92
3 Lead TO-92
3 Lead TO-92
3 Lead TO-92
3 Lead TO-220
3 Lead TO-220
3 Lead TO-220
3 Lead TO-220
5 Lead TO-220
5 Lead TO-220
5 Lead TO-220
5 Lead TO-220
8 Lead SOIC
1%
1%
3.3V
5.0V
3.3V
5.0V
3.3V
5.0V
3.3V
5.0V
3.3V
5.0V
3.3V
5.0V
3.3V
5.0V
3.3V
5.0V
3.3V
5.0V
3.3V
5.0V
3.3V
5.0V
3.3V
5.0V
3.3V
5.0V
3.3V
5.0V
0.5%
0.5%
1%
1%
0.5%
0.5%
1%
1%
SPX2954N-5.0
0.5%
0.5%
1%
SPX2954AN-3.3
SPX2954AN-5.0
SPX2954U3-3.3
SPX2954U3-5.0
SPX2954AU3-3.3
SPX2954AU3-5.0
SPX2954U5-3.3
SPX2954U5-5.0
SPX2954AU5-3.3
SPX2954AU5-5.0
SPX2954S-3.3
1%
0.5%
0.5%
1%
1%
0.5%
0.5%
1%
1%
8 Lead SOIC
SPX2954S-5.0
0.5%
0.5%
1%
8 Lead SOIC
SPX2954AS-3.3
SPX2954AS-5.0
SPX2954M3-3.3
SPX2954M3-5.0
SPX2954AM3-3.3
SPX2954AM3-5.0
8 Lead SOIC
3 Lead SOT-223
3 Lead SOT-223
3 Lead SOT-223
3 Lead SOT-223
1%
0.5%
0.5%
Corporation
SIGNAL PROCESSING EXCELLENCE
Sipex Corporation
Headquarters and Main Offices:
22 Linnell Circle
Billerica, MA 01821
TEL: (978) 667-8700
FAX: (978) 670-9001
e-mail: sales@sipex.com
233 South Hillview Drive
Milpitas, CA 95035
TEL: (408) 935-7600
FAX: (408) 934-7500
Sipex Corporation reserves the right to make changes to any products described herein. Sipex does not assume any liability arising out of the application or use of any product or circuit described
hereing; neither does it convey any license under its patent rights nor the rights of others.
Rev. 11/21/00
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