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SPX2955U3

Datasheet SPX2955AS, SPX2955AS-3.3, SPX2955AS-5.0, SPX2955AT3, SPX2955AT3-3.3 Datasheet (Sipex Corporation)

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Page 1
Rev. 11/21/00
ALPHA AS2930
1
8-Pin Surface Mount
Top View
2
3
4
5
6
7
8
OUTPUT
SENSE
SHUTDOWN
GROUND
INPU T
FEEDBACK
5V/ 3.3V TAP
ERROR
SPX2955/56/57
350mA Low Drop Out Voltage Regulator
with Shutdown
(PRELIMINARY INFORMATION)
FEATURES
APPLICATIONS
•
Output Accuracy 5V, 3.3V@ 350mA Output • Battery Powered Systems
•
Very Low Quiescent Current
•
Cordless Telephones
•
Low Dropout Voltage
•
Radio Control Systems
•
Extremely Tight Load And Line Regulation
•
Portable/Palm Top/Notebook Computers
•
Very Low Temperature Coefficient
•
Portable Consumer Equipment
•
Current & Thermal Limiting
•
Portable Instrumentation
•
Error Flag Warns Of Output Dropout
•
Automotive Electronics
•
Logic-Controlled Electronic Shutdown
•
SMPS Post-Regulator
•
Output Programmable From 1.24V to 29V
•
Voltage Reference
PRODUCT DESCRIPTION
The SPX2955/56/57 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 SPX2955/56/57 features very low quiescent current (100µA Typ.) and very low dropout voltage. This includes a tight initial tolerance of 1% max and 2% max., and very low output temperature coefficient, making the SPX2955/56/57 useful as a low-power voltage reference.
The error flag output feature is used as power-on reset for warning of a low output voltage, due to a falling voltage input of batteries. Another feature is the logic-compatible shutdown input which enables the regulator to be switched on and off. The SPX2955/56/57 is offered in 3-pin and 5-pin TO-220 package compatible with other 5 volt and adjustable regulators, in 8-Pin Plastic Dip SO-8 (same pin out as SPX2951) and surface mount TO-263 packages.
The regulator output voltage (of the 8-pin package and 5-pin TO-220 & TO-263) may be pin-strapped for a 5V and 3.3V or programmed from 1.24V to 29V with an external pair of resistors. Look for SPX2951 for 150mA and SPX2954 for 250mA applications.
PIN CONNECTIONS
TO-263-5 Package
Top View
1234
5
SPX2956/57
INPUT
GND
INPUT
ERROR
OUTPUT
GND
Five Lead Package Pin Functions:
1)
SPX2956 SPX2957
3)
4)
5)
ADJUST
SHUTDOWN
OUTPUT
SHUTDOWN
2)
Front View
3
2
1
TO-263-3 Package
V
OUT
GND
V
IN
SPX2955
Top View
SPX2956/57
TO-220-5 Package
54321
Front View
TO-220-3 Package
SPX2955
1
2
3
V
OUT
GND
V
IN
Page 2
Rev. 11/21/00
SPX2955/56/57
ABSOLUTE MAXIMUM RATINGS
Power Dissipation..........................................Internally Limited Operating Input Supply Voltage....................... 3.0V to +60V
Lead Temp. (Soldering, 5 Seconds) ................................ 260°C Feedback Input Voltage .................................. -1.5V to +30V
Storage Temperature Range.............................. -65° to +150°C Shutdown Input Voltage..................................-0.3V to +30V
Operating Junction Temperature Range (Note 9) Error Comparator Output................................-0.3V to +30V
SPX2955/56/57...................................... -40C° to +125°C ESD Rating ............................................................2KV Min
ELECTRICAL CHARACTERISTICS
at VS=±15V,TA=25°C, unless otherwise specified.
Boldface
applies over the full
operating temperature range.
PARAMETER
CONDITIONS
(Note 2)
Typ.
SPX2955/56/57A
Min Max
SPX2955/56
Min Max
UNITS
3.3V Version
Output Voltage
-
40°C
≤
T
J
≤
+125°C
1mA ≤I
L
≤
350mA
3.3
3.3
3.267
3.217
3.333
3.382
3.234
3.185
3.366
3.415
V
5V Version
Output Voltage
-
40°C
≤
T
J
≤
+125°C
1mA ≤I
L
≤
350mA
5.0
5.0
4.950
4.880
5.050
5.120
4.900
4.870
5.100
5.130
V
All Voltage Options
SPX2955/56/57A SPX2955/56/57
Output Voltage Temperature Coefficient
(Note 1)
20
100 150
ppm/°C
Line Regulation ( Note 3)
6V ≤ V
IN
≤30V (Note 4)
0.03 0.1
0.40
0.20
0.80
%max
Load Regulation ( Note 3 ) IL = 1 to 350mA
I
L
= 0.1 to 1mA
0.04 0.20
0.30
0.30
0.50
%max
Dropout Voltage ( Note 5 )
I
L
= 1mA
I
L
= 100mA
I
L
= 250mA
I
L
= 350mA
60
220
250
375
100
150
250
300
300
420
400
500
100
150
250
300
350
420
500
600
mV
Ground Current
I
L
= 1mA
I
L
= 100mA
I
L
= 250mA
I
L
= 350mA
50
0.5
4
5
100
150
1
2
8
10
10
15
100
150
1
2
8
10
10
15
µ
A
mA
Current Limit
V
OUT
= 0 700
800
700
800
mA
Thermal Regulation 0.05 0.2 0.2 %/w
Output Noise, 10Hz to 100kHz I
L
= 100mA
C
L
= 2.2µF
C
L
= 33µF
400
260
µ
V
Vrms
Page 3
Rev. 11/21/00
SPX2955/56/57
(Continued)
PARAMETER
CONDITIONS
(Note 2)
Typ. SPX2955/57A
Min Max
SPX2955/57
Min Max
UNITS
Adjustable Versions only
Typ. SPX2955/57A
SPX2955/57B
Reference Voltage
1.235 1.210
1.200
1.260
1.270
1.200
1.990
1.270
1.280
V
Reference Voltage Over Temperature (Note 6)
1.185 1.285 1.185 1.285 V
Feedback Pin Bias Current
20 40
60
60
80
NA
Reference Voltage Temperature Coefficient
(Note 7)
50
ppm/°C
Feedback Pin Bias Current Temperature Coefficient
0.1
nA/°C
Error Comparator
Output Leakage Current V
0H
= 30V 0.01 1.00
2.00
1.00
2.00
µ
A
Output Low Voltage VIN = 4.5V
I0L = 400µA
150 250
400
250
400
mV
Upper Threshold Voltage (Note 8) 60 40
25
40
25
mV
Lower Threshold Voltage (Note 8) 75 95
140
95
140
mV
Hysteresis (Note 8) 15 mV
Shutdown Input
Input logic Voltage Low (Regulator ON)
High (Regulator OFF)
1.3
2.0
0.7
2.0
0.7
V
Shut down Pin Input Current VS = 2.4V
V
S
= 30V
30
450
50
100
600
750
90
150
800
1000
µ
A
Regulator Output Current in Shutdown 3 10
20
15
25
µ
A
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 T
j
= 25°C, VIN = 6V, IL = 100µA and CL = 1µF. Additional conditions for the 8-pin versions are
feedback tied to 5V tap and output tied to output sense (V
OUT
= 5V) and V
SHUTDOWN
≤ 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 SPX2955/56/57 is tested at 150°C for I
L
= 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:
V
REF
≤
V
OUT
≤ (Vin - 1V), 2.3 ≤Vin≤30V, 100µA≤I
L
≤
250 mA, T
J
≤
T
JMAX
.
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 = V
OUT/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 V
OUT
as
V
OUT
is varied, with the dropout warning occurring at typically 5% below nominal, 7.5% guaranteed.
Note 8:
V
SHUTDOWN
≥ 2V, VIN ≤ 30V, V
OUT
=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.
Page 4
Rev. 11/21/00
FEEDBACK
INPUT
OUTPUT
UNREGULATED DC
SHUTDOWN
GROUND
ERROR
______
5V TAP
SENSE
5V @ 350mA
MAX
TO CMOS OR TTL
REFERENCE
ERROR DETECTION COMPARATOR
ERROR AMPLIFIER
1.23V
FROM CMOS OR TTL
+
+
+
+
+
+
60 mV
3
7
8
1
2
6
5
4
Ω
..
60k
330k
180k
Ω
..
Ω
..
µ
.. 1 F
_
_
SPX2955/56/57 Block Diagram
SPX2955/56/57
Page 5
Rev. 11/21/00
SPX2955/56/57
APPLICATION HINTS
EXTERNAL CAPACITORS
The stability of the SPX2955/56/57 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. 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 SPX2955/56/57, 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 SPX2955/56/57, a minimum load of 10mA 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 0.1µF tantalum or aluminum electrolytic capacitor should be placed from the input to the ground. Instability can occur if there is stray capacitance to the SPX2955/56/57 feedback terminal (pin 7). This could cause more problems when using a higher value of external resistors to set the output voltage.
This problem can be fixed by adding a 100pF capacitor between output and feedback and increasing the output capacitor to at least
3.3µF.
ERROR DETECTION COMPARATOR OUTPUT
The Comparator produces a logic low output whenever the SPX2955/56/57 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 SPX2955/56/57 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 SPX2955/56/57’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. 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.
PROGRAMMING THE OUTPUT VOLTAGE OF SPX2955/56/57
The SPX2956/57 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).
+
+
+
+
4.75V
OUTPUT
VOLTAGE
ERROR*
_______
INP UT
VOLTAGE 1.3V
5.0V
Figure 1. ERROR Output Timing
_______
* See App lication Info.
100K
OUTPUT
ERROR
ERROR
______
SD
V
OUT
GND
FB
+V
IN
+V
IN
1.23V
1.2 to 29V
R
1
.01uF
10uF
R
2
V
REF
3
8
5
1
4
7
SHUTDOWN
INPUT
+
Figure 2. Adjustable Regulator
SPX2955/57
Page 6
Rev. 11/21/00
SPX2955/56/57
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::
V
OUT
= V
REF
× ( 1 + R1\ R2 )+ IFBR
1
The V
REF
is 1.235 and IFB is the feedback bias current, nominally
-20nA. The minimum recommended load current of 1 µA forces an upper limit of 1.2 MΩ on value of R2. If no load is presented the I
FB
produces an error of typically 2% in V
OUT
, which may be
eliminated at room temperature by trimming R
1
. 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 SPX2955/56/57 typically draws 60 µA at no load with Pin 2 open-circuited this is a small price to pay
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 SPX2955/56/57 but is relatively inefficient, as increasing the capacitor from 1µF to 220µF only decreases the noise from 430µV to 160µV Vrms for a 100kHz bandwidth at 5V output. Noise could also be reduced fourfold by a bypass capacitor across R
1
,
since it reduces the high frequency gain from 4 to unity. Pick
C
BYPASS
≅
1 / 2πR
1
× 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 100µV Vrms 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.
HEAT SINK REQUIREMENTS
Depending on the maximum ambient temperature and maximum power dissipation a heat sink may be required with the SPX2955/56/57. 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 heat sink 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:
P
TOTAL
= (VIN - 5) IL + (VIN)I
G
Next step is to calculate the temperature rise T
R
(max). TJ (max)
maximum allowable junction temperature, T
A
(max) maximum
ambient temperature :
T
R
(max) = TJ (max) - TA (max)
Junction to ambient thermal resistance
θ
(j-A)
can be calculated
after determining of P
TOTAL & TR
(max):
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 heat sink. If the value is below 60°C/W then the heat sink is required and the thermal resistance of the heat sink can be calculated by the following formula,
θ
(J-C)
junction to case,
θ
(C-H)
case to heat sink,
θ
(H-A)
heat sink to ambient:
θ
(J-A)
=
θ
(J-C)
+
θ
(C-H)
+
θ
(H-A)
+
2.2 uF
+
SPX2955
I
in
V
in
I
G
I
L
5V
IN
OUT
GND
LOAD
I
IN
= I
L
+ I
G
Figure 3. 5V Regulator Circuit
Page 7
Rev. 11/21/00
SPX2955/56/57
TYPICAL APPLICATIONS
OUTPUT
ERROR
ERROR
______
SD
V
OUT
GND
FB
+V
IN
+V
IN
*V
OUT
= V
IN
3
8
5
1
4
7
SHUTDOWN
INPUT
SPX2955/57
Wide Input Voltage Range Current
*MINIMUM INPUT-OUTPUT VOLTAGE RANGES FROM 4mV TO 400mV. DEPENDING ON LOAD CURRENT. CURRENT LIMIT IS TYPICALLY 160mA
V
OUT
GND
+V
IN
+V
IN
*V
OUT
= 5V
4
SPX2955
10uF
+
SPX2955 FIXED +5V REGULATOR
Page 8
Rev. 11/21/00
SPX2955/56/57
ORDERING INFORMATION
Ordering No. Precision Output Voltage Packages
SPX2955U3
2% Adj 3 Lead TO-220
SPX2955U3-3.3
2% 3.3V 3 Lead TO-220
SPX2955U3-5.0
2% 5.0V 3 Lead TO-220
SPX2955AU3
1% Adj 3 Lead TO-220
SPX2955AU3-3.3
1% 3.3V 3 Lead TO-220
SPX2955AU3-5.0
1% 5.0V 3 Lead TO-220
SPX2955U5
2% Adj 5 Lead TO-220
SPX2955U5-3.3
2% 3.3V 5 Lead TO-220
SPX2955U5-5.0
2% 5.0V 5 Lead TO-220
SPX2955AU5
1% Adj 5 Lead TO-220
SPX2955AU5-3.3
1% 3.3V 5 Lead TO-220
SPX2955AU5-5.0
1% 5.0V 5 Lead TO-220
SPX2955T3
2% Adj 3 Lead TO-263
SPX2955T3-3.3
2% 3.3V 3 Lead TO-263
SPX2955T3-5.0
2% 5.0V 3 Lead TO-263
SPX2955AT3
1% Adj 3 Lead TO-263
SPX2955AT3-3.3
1% 3.3V 3 Lead TO-263
SPX2955AT3-5.0
1% 5.0V 3 Lead TO-263
SPX2955T5
2% Adj 5 Lead TO-263
SPX2955T5-3.3
2% 3.3V 5 Lead TO-263
SPX2955T5-5.0
2% 5.0V 5 Lead TO-263
SPX2955AT5
1% Adj 5 Lead TO-263
SPX2955AT5-3.3
1% 3.3V 5 Lead TO-263
SPX2955AT5-5.0
1% 5.0V 5 Lead TO-263
SPX2955S
2% Adj 8 Lead SOIC
SPX2955S-3.3
2% 3.3V 8 Lead SOIC
SPX2955S-5.0
2% 5.0V 8 Lead SOIC
SPX2955AS
1% Adj 8 Lead SOIC
SPX2955AS-3.3
1% 3.3V 8 Lead SOIC
SPX2955AS-5.0
1% 5.0V 8 Lead SOIC
SPX2955AS-3.3
1% 3.3V 8 Lead SOIC
SPX2955AS-5.0
1% 5.0V 8 Lead SOIC
SPX2956U3-3.3
2% 3.3V 3 Lead TO-220
SPX2956U3-5.0
2% 5.0V 3 Lead TO-220
SPX2956AU3-3.3
1% 3.3V 3 Lead TO-220
SPX2956AU3-5.0
1% 5.0V 3 Lead TO-220
SPX2956U5-3.3
2% 3.3V 5 Lead TO-220
SPX2956U5-5.0
2% 5.0V 5 Lead TO-220
SPX2956AU5-3.3
1% 3.3V 5 Lead TO-220
SPX2956AU5-5.0
1% 5.0V 5 Lead TO-220
SPX2956T3-3.3
2% 3.3V 3 Lead TO-263
SPX2956T3-5.0
2% 5.0V 3 Lead TO-263
Page 9
Rev. 11/21/00
SPX2955/56/57
ORDERING INFORMATION
Ordering No. Precision Output Voltage Packages
SPX2956AT3-3.3
1% 3.3V 3 Lead TO-263
SPX2956AT3-5.0
1% 5.0V 3 Lead TO-263
SPX2956T5-3.3
2% 3.3V 5 Lead TO-263
SPX2956T5-5.0
2% 5.0V 5 Lead TO-263
SPX2956AT5-3.3
1% 3.3V 5 Lead TO-263
SPX2956AT5-5.0
1% 5.0V 5 Lead TO-263
SPX2956S-3.3
2% 3.3V 8 Lead SOIC
SPX2956S-5.0
2% 5.0V 8 Lead SOIC
SPX2957U3
2% Adj 3 Lead TO-220
SPX2957AU3
1% Adj 3 Lead TO-220
SPX2957U5
2% Adj 5 Lead TO-220
SPX2957AU5
1% Adj 5 Lead TO-220
SPX2957T3
2% Adj 3 Lead TO-263
SPX2957AT3
1% Adj 3 Lead TO-263
SPX2957T5
2% Adj 5 Lead TO-263
SPX2957AT5
1% Adj 5 Lead TO-263
SPX2957S
2% Adj 8 Lead SOIC
SPX2957AS
1% Adj 8 Lead SOIC
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.
Corporation
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