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SPX2950/SPX2951
150mA Low Dropout Voltage Regulator
FEATURES
5.0V and 3.3V at 150mA Output Accurate: 0.5% for SPX2950A/SPX2951A Very Low Quiescent Current Low Dropout Voltage: 300mV at 150mA Extremely Tight Load and Line Regulation Very Low Temperature Coefficient Current & Thermal Limiting Need Only 1F for Stability Offered in TO-92 (SPX2950) and SOIC (SPX2951) Direct Replacement for LP2950/LP2951 SPX2951 versions only Error Flag Warns of Output Dropout Logic-Controlled Electronic Shutdown Output Programmable From 1.24 to 30V
APPLICATIONS
Battery Powered Systems Cordless Telephones Radio Control Systems Portable/Palm Top/Notebook Computers Portable Consumer Equipment Portable Instrumentation Avionics SMPS Post-Regulator Voltage Reference Automotive Electronics
DESCRIPTION
The SPX2950 and SPX2951 are low power voltage regulators. These devices are an excellent choice for use in battery-powered applications such as cordless telephones, radio control systems, and portable computers. The SPX2950 and SPX2951 feature low quiescent current and low dropout voltage (typ. 20mV at 100A and 300mV at 150mA). This includes a tight initial tolerance of (0.5% for SPX2950A/SPX2951A), extremely good load and line regulation (0.05% typ.), and very low output temperature coefficient (20ppm/ C typ.), making the SPX2950/SPX2951 useful as a low-power voltage reference. The error flag output feature is used as a power-on reset for warning of a low output voltage, due to a falling voltage. The logic compatible shutdown feature enables the regulator to be switched ON and OFF. The SPX2950 is offered in a 3-pin TO-92 package compatible with other 5.0V, 3.3V regulators. The SPX2951 is availiable in an 8-lead SOIC package.
UNREGULATED DC
5V 7
FEEDBACK
+
8
INPUT
1
OUTPUT
2
SENSE
+ _
FROM CMOS OR TTL
180k 6
ERROR AMPLIFIER 5V TAP
3
SHUTDOWN 60 mV
330k +
60k
+
5
______ ERROR
+ _
ERROR DETECTION COMPARATOR
1F . .
TO CMOS OR TTL
+ 1.23V
4
REFERENCE GROUND
Block Diagram of SPX2951, 8 Lead 5V Version
Rev. 3/6/03
SPX2950/SPX2951 150mA Low Dropout Voltage Regulator
(c)Copyright 2003 Sipex Corporation
1
ABSOLUTE MAXIMUM RATINGS
Power Dissipation ........................................................ Internally Limited Lead Temp. (Soldering, 5 Seconds) ............................................. 260C Storage Temperature Range ........................................ -65C to +150C Operating Junction Temperature Range ....................... -40C to +125C Input Supply Voltage ........................................................ -0.3V to +30V Feedback Input Voltage ................................................ -1.5V to +30V Shutdown Input Voltage ................................................ -0.3V to +30V Error Comparator Output .............................................. -0.3V to +30V ESD Rating ............................................................................ 2kV Min
ELECTRICAL CHARACTERISTICS
Electrical characteristics at VIN = VO+1V, IL=100A, CL=1F (note 2) TA=25C, unless otherwise specified. Boldface applies over the full operating temperature range. PARAMETER CONDITIONS MIN TYP SPX2950AC SPX2951AC 3.3V Version Output Voltage TJ=25C -25CTJ85C Full Operating Temperature 100A IL 150mA TJTJMAX TJ=25C -25CTJ85C Full Operating Temperature 100AIL150mA TJTJMAX (Note1) VO+1V VIN 30V (Note 4) IL=100A IL=100mA IL=150mA IL=100A IL=100mA IL=150mA VOUT=0 CL=1F CL=200F CL=3.3F, Bypass=0.01F from pin 7 to pin1 (SPX2951) 1.220 Over Temperature (Note 6) 1.190 40 20 0.1 3.284 3.267 3.260 3.254 3.3 3.3 3.3 3.3 3.317 3.333 3.340 3.346 3.267 3.251 3.324 3.221 3.3 3.3 3.3 3.3 3.333 3.350 3.366 3.379 V MAX MIN TYP SPX2950C SPX2951C MAX UNITS
Output Voltage 5.0V Version Output Voltage
V
4.975 4.950 4.940 4.925
5.0 5.0 5.0 5.0
5.025 5.050 5.060 5.075
4.950 4.925 4.900 4.880
5.0 5.0 5.0 5.0
5.050 5.075 5.100 5.120
V
Output Voltage All Voltage Options Output Voltage Temperature Coefficient Line Regulation (Note 3) Dropout Voltage (Note5)
V
20 0.03 0.04 20 270 300 150 3 5 230 0.05 430 160 100 SPX2951AC 1.235
100 0.1 0.1 80 450 500 170 6 8 0.2
50 0.04 0.1 20 270 300 150 3 5 230 0.05 430 160 100 SPX2951C 1.210 1.185 40 50 0.1 1.235
150 0.2 0.2 80 450 500 170 6 8 0.2
ppm/C % % mV mV mV A mA mA mA %/W Vrms Vrms Vrms
Load Regulation (Note 3) 100AIL150mA
Ground Current
Current Limit Thermal Regulation Output Noise, 10Hz to 100kHz
8-Pin Version only Reference Voltage Reference Voltage Feedback Pin Bias Current Reference Voltage Temperature Coefficient Feedback Pin Bias Current Temperature Coefficient
1.250 1.270 60
1.260 1.285 60
V V nA ppm/C nA/C
Rev. 3/6/03
SPX2950/SPX2951 150mA Low Dropout Voltage Regulator
(c)Copyright 2003 Sipex Corporation
2
ELECTRICAL CHARACTERISTICS: Continued
Electrical characteristics at VIN = VO+1V, IL=100A, CL=1F (note 2) TA=25C, unless otherwise specified. Boldface applies over the full operating temperature range. PARAMETER Error Comparator Output Leakage Current Output Low Voltage V0H=30V VIN=VO-0.5V I0L=400A 40 0.01 150 60 75 15 1.3 2.0 30 400 3 50 800 10 0.7 2.0 30 400 3 50 800 10 95 1 250 40 0.01 150 60 75 15 1.3 0.7 95 1 250 A mV mV mV mV V V A A A CONDITIONS MIN TYP MAX MIN TYP MAX UNITS
Upper Threshold Voltage (Note 7) Lower Threshold Voltage (Note 7) Hysteresis Shutdown Input Input Logic Voltage Low (Regulator ON) High (Regulator OFF) (Note 7)
Shutdown Pin Input Current VS=2.4V VS=30V Regulator Output Current (Note 8) in Shutdown
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 = 25C, VIN = VO +1V, IL = 100A and CL = 1F. 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 SPX2951 is tested at IL = 1mA. 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 100mV 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: VREFVOUT(VIN -1V),2.3VIN30V, 100AIL150mA, TJTJMAX. 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 95mV x 5V/1.235 = 384mV. Thresholds remain constant as a percent of VOUT as VOUT 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/ 3.3V tap.
Rev. 3/6/03
SPX2950/SPX2951 150mA Low Dropout Voltage Regulator
(c)Copyright 2003 Sipex Corporation
3
TYPICAL PREFORMANCE CHARACTERISTICS
6 5
OUTPUT VOLTAGE (VOLTS) INPUT CURRENT (A)
250 225
R L = 50k
GROUND PIN CURRENT (mA)
10
200 175 150 125 100 75 50 25 0 0 1 2 3 4 5 6 0 1 2 3 4 5 6 7 8 9 10
INPUT VOLTAGE (VOLTS) RL =
8
4
R L =50k
1
3
R L =50k
2 1 0
INPUT VOLTAGE (VOLTS)
0.1
0.01 0.1
1
10
100
LOAD CURRENT (mA)
Dropout Characteristics
Input Current
Quiescent Current
320 280
GROUND CURRENT (A) INPUT CURRENT (mA)
240 200 160
IL= 0 I L = 1mA
120 80 40 0 0 1 2 3 4 5 6 7 8
160 150 140 130 120 110 100 90 80 70 60 50 40 30 20 10 0 0 1 2 3 4 5 6
6
GROUND CURRENT (mA)
R L =50 VOUT = 5V
5
V IN = 6V I L = 100mA
4
3 7 8 9 10 -75 -50 -25 0 25 50 75 100 125 150
TEMPERATURE (C)
INPUT VOLTAGE (VOLTS)
INPUT VOLTAGE (VOLTS)
Ground Current
8 7
Input Current
190
Ground Current
QUIESCENT CURRENT (A)
GROUND CURRENT (mA)
6
I L =100mA
170
V IN =6V I L =100uA
5 4 3 2 1 0 0 1 2 3 4 5 6 7 8
150
130
-75 -50 -25
0
25 50
75 100 125 150
INPUT VOLTAGE
TEMPERATURE (C)
Ground Current
Quiescent Current
Rev. 3/6/03
SPX2950/SPX2951 150mA Low Dropout Voltage Regulator
(c)Copyright 2003 Sipex Corporation
4
TYPICAL PREFORMANCE CHARACTERISTICS: (Continued)
500
I L = 150mA
SHORT CIRCUIT CURRENT (mA)
500
240 230
400
DROP-OUT VOLTAGE (mV) DROP-OUT VOLTAGE (mV)
400
220 210 200 190 180 170 -75 -50 -25
300 200
~ ~
300
200
TJ = 25C
40 20 0 -75 -50 -25 0 25 50 75 100 125 150
I L = 100A
100 0 100A 1mA 10mA 100mA
0
25 50
75 100 125 150
TEMPERATURE (C)
OUTPUT CURRENT
TEMPERATURE (C)
Drop-Out Voltage
8
V OUT = 5V
Drop-Out Voltage
2.5
T A = 125C
Short Circuit Current
100 mV 50 mV
INPUT OUTPUT VOLTAGE VOLTAGE CHANGE
6
COMPARATOR OUTPUT (V) SINK CURRENT (mA)
2.0
4
HYSTERESIS
0 -50 mV ~ ~ 8V 6V 4V 0 200 400
TIME(s) C L = 1F I L = 1mA V OUT = 5V
1.5
T A = 25C
2 0 -2 0 1
PULLUP RESISTOR TO SEPARATE 5V SUPPLY
1.0
T A = -55C
0.5 0.0 2 3 4 5 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9
OUTPUT LOW VOLTAGE (V) INPUT VOLTAGE (V)
600
800
Error Comparator Output
10
IO = 100A
SPX2951 Comparator Sink Current
90 80
RIPPLE REJECTION (dB)
Line Transient Response
90 80
RIPPLE REJECTION (dB)
OUTPUT IMPEDANCE (OHMS)
5 2 1 0.5 0.2 0.1 0.05 0.02 0.01 10 100 1K 10K 100K 1M
FREQUENCY (Hz) V OUT = 5V C L = 1F I O = 1mA I O = 100mA
70
IL = 0
70 60 50 40 30 20
I L = 1mA
C L = 1F V IN = 6V V OUT = 5V
60 50 40 30 20 10 1 10 2 10 3 10 4 10 5 10 6
C L = 1F V IN = 6V V OUT = 5V I L = 100A
I L = 10mA
10 1
10 2
10 3
10 4
10 5
10 6
FREQUENCY (Hz)
FREQUENCY (Hz)
Output Impedance
Ripple Rejection
Ripple Rejection
Rev. 3/6/03
SPX2950/SPX2951 150mA Low Dropout Voltage Regulator
(c)Copyright 2003 Sipex Corporation
5
TYPICAL PREFORMANCE CHARACTERISTICS: (Continued)
2.3 20 50 0
FEEDBACK CURRENT (A)
PIN 7 DRIVEN BY EXTERNAL SOURCE (REGULATOR RUN OPEN LOOP)
MINIMUM OPERATING VOLTAGE (V)
10
BIAS CURRENT (nA)
2.1
-50 -100 -150 -200 -250
TA=1 25C
0
-10
1.9
T A = 25C T A = 55C
-20
1.7 -75
-30 -50 -25 0 25 50 75 100 125 150 -75 -50 -25 0 25 50 75 100 125 150
TEMPERATURE TEMPEATURE (C)
-2.0
-1.5
-1.0
-0.5
0
0.5
1.0
FEEDBACK VOLTAGE (V)
SPX2951 Minimum Operating Voltage
SPX2951 Feedback Bias Current
SPX2951 Feedback Pin Current
250 200 150
LOAD OUTPUT VOLTAGE CURRENT CHANGE (mV) LOAD OUTPUT VOLTAGE CURRENT CHANGE (mV)
80 60 40 20 0 -20 -40 -60
~ ~ C L = 10F V OUT = 5V
7 6
SHUTDOWN OUTPUT PINOUT VOLTAGE (V) VOLTAGE (V)
C L = 1F
5 4 3 2 1 0 2 0 -2 -100 0 100 200 300 400 500 600 700
TIME (us) C L = 10F I L = 10mA V IN = 8V V OUT = 5V
100 50 0 -50 -100
~ ~ C L = 1F V OUT = 5V
100
A
mA
100 100
100 0 1 2
TIME (ms)
A A
3
4
5
0
4
8
12
16
20
TIME (ms)
Load Transient Response
Load Transient Response
Enable Transient
120 100
OUTPUT CURRENT (mA)
TO-92 PACKAGE 0.25" LEADS SOLDERED TO PC BOARD Vout=5V T JMAX = 125 C
400
120
8-PIN MOLDED
PIN 2 TO PIN 4 RESISTANCE (k)
100 300
OUTPUT CURRENT (mA)
80 60 40 20 0 0 5 10 15
T A = 85 C
80 60
DIP SOLDERED TO PC BOARD T JMAX = 125 C V OUT = 5V
200
T A = 25C
T A =25 C
40 20
T A = 50C T A = 85C
100
0 20 25 30 -75 -50 -25 0 25 50 75 100 125 150
0 0 5 10 15 20 25 30
INPUT VOLTAGE (V)
TEMPERATURE (C)
INPUT VOLTAGE (V)
SPX2950 Maxium Rated Output
SPX2951 Divider Resistance
SPX2950 Maxium Rated Output Current
Rev. 3/6/03
SPX2950/SPX2951 150mA Low Dropout Voltage Regulator
(c)Copyright 2003 Sipex Corporation
6
TYPICAL APPLICATIONS:
1.8 1.6 1.4 1.2 -2 1.0 1
1.25W
5 4 2 0
3.5
I L = 100mA
3.0
C L = 1F
2.5
C L = 220F
2.0 1.5 ~ ~ 1.0 0.5 0.0 0 10 20 30 40 50
TIME (s) C L = 3.3F C BYP = 0.1F
0.8 0.6 -75 -50 -25 0 25 50 75 100 125 150
TEMPERATURE (C)
0 -1
10 2
10 3
10 4
10 5
FREQUENCY (Hz), C BYP =0.1uF
Shutdown Threshold Voltage
Thermal Response
Output Noise
30 25 20 15 10 5 0 ~ ~ 10 5 0 -5 -10 5 10 15 20 25 30
T J = 125 C I L = 100A T J = 150 C I L = 1mA I L = 100A
80
I L = 50mA
70 60 50 40 30 20 10 10 1 10 2 10 3 10 4 10 5 10 6
C L = 1F VIN = 6V VOUT = 5V I L = 100mA
INPUT VOLTAGE (V)
FREQUENCY (Hz)
Line Regulation
Ripple Rejection
Rev. 3/6/03
SPX2950/SPX2951 150mA Low Dropout Voltage Regulator
(c)Copyright 2003 Sipex Corporation
7
APPLICATION HINTS EXTERNAL CAPACITORS The stability of the SPX2950/SPX2951 requires a 1F 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 below -25C solid tantalum is recommended since the many aluminum types have electrolytes that freeze at about -30C. The ESR of about 5 or less and resonant frequency above 500kHz are the most important parameters in the value of the capacitor. The capacitors value may 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 0.33F and 0.1F for 1mA. More output capacitance is needed for the 8-pin version at voltages below 5V since it runs the error amplifier at lower gain. At worst case 3.3F or greater must be used for the condition of 150mA load at 1.23V output. The SPX2950/51 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 applications like CMOS RAM keep-alive. When setting the output voltage of the SPX2950/51 version with external resistors, a minimum load of 1A 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 1F tantalum or aluminum electrolytic capacitor should be placed from the input to the ground. Instability can occur if there is stray capacitance to the SPX2951 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 3.3F.
4.75V OUTPUT VOLTAGE _______ ERROR*
+5.0V
INPUT VOLTAGE
+ +
+1.3V
* See Application Info.
Fig. 1 ERROR Output Timing
ERROR DETECTION COMPARATOR OUTPUT The comparator produces a logic low output whenever the SPX2951 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 SPX2951 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 SPX2951'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 400A, this value adds to battery drain in a low battery condition. Suggested values range from 100K to 1M. If the output is unused this resistor is not required.
(c)Copyright 2003 Sipex Corporation
Rev. 3/6/03
SPX2950/SPX2951 150mA Low Dropout Voltage Regulator
8
PROGRAMMING THE OUTPUT VOLTAGE OF SPX2951 The SPX2951 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). 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: VOUT = VREF x (1 + R1/R2)+ IFBR1 The VREF is 1.235 and IFB is the feedback bias current, nominally -20nA. The minimum recommended load current of 1 A forces an upper limit of 1.2M 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 12A. Since the SPX2951 typically draws 60A 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 SPX2950 but is relatively inefficient, as increasing the capacitor from 1F to 220F only decreases the noise from 430V to 160VRMS for a 100kHz bandwidth at 5V output. Noise could also be reduced fourfold by a bypass capacitor across R1, since it reduces the high frequency gain from 4 to unity. Pick CBYPASS (1 / 2R1 x 200 Hz) or choose 0.01F. When doing this, the output capacitor must be increased to 3.3F to maintain stability. These changes reduce the output noise from 430V to 100VRMS 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.
TYPICAL APPLICATIONS
+V IN
100K ERROR OUTPUT
5
8
______ ERROR
+V IN V OUT
1
1.2 to 30V
SPX2951
SHUTDOWN INPUT
3
SD GND
4
R1 FB
7
+
3.3F .01F
1.23V
V REF
R2
Figure 2. Adjustable Regulator
Rev. 3/6/03
SPX2950/SPX2951 150mA Low Dropout Voltage Regulator
(c)Copyright 2003 Sipex Corporation
9
TYPICAL APPLICATIONS: (Continued)
+V IN
+V IN
470K
5
8
8
______ ERROR
+V IN V OUT
1
ERROR
5
V OUT
470k
OUTPUT
______ ERROR
+V IN
1
V OUT
*V OUT = V IN
SPX2951
+ 3
SPX2951
R1 1F
SHUTDOWN INPUT
3
SD GND
4
SD GND
4
RESET
FB
7
FB
7
R2
*MINIMUM INPUT-OUTPUT VOLTAGE RANGES FROM 40mV to 400mV. DEPENDING ON LOAD CURRENT.
Figure 3. Latch Off When Error Flag Occurs
Figure 4. Wide Input Voltage Range Current Limiter
+
6V SEALED LEADACID BATTERY SOURCE
120k FB
1.5k 1N457 8 +V IN 1
SPX385
V OUT
MAIN V+
SPX2951
FOR 5.5 V
400k 3 SD 100k GND 4
SENSE 2
+
MEMORY V+
1F
20k
NI-CAD BACKUP BATTERY
Figure 5.Low Battery Disconnect
Rev. 3/6/03
SPX2950/SPX2951 150mA Low Dropout Voltage Regulator
(c)Copyright 2003 Sipex Corporation
10
TYPICAL APPLICATIONS: (Continued)
39k 5
RESET C4 +
8
+VIN ERROR
2
SENSE VOUT
1
+VOUT=5V + 1F
SPX2951
3
SD GND FB TAP
7
39k
4
6
1%
100k
C1 +
100k <5.8V**
6V LEADACID BATTERY
1%
1k
C2 +
100k <6.0V**
1%
1k
C3 +
100k
<6.2V** R1 10k
* OPTIONAL LATCH OFF WHEN DROPOUT OCCURS. ADJUST R3 FOR C2 SWITCHING WHEN VIN IA 6.0V * OUTPUTS GO LOW WHEN VIN DROPS BELOW DESIGNATED THRESHOLDS
1%
20k
Figure 6. Regulator with State-of Charge Indicator
+V IN
8 AUX SHUTDOW INPUT
ON OFF
3
+V IN SD
10K .
_______ ERROR 5 5 DEGREE SHUTDOWN FLAG
.
SPX2951
V OUT GND
+
1
FB
7
4
TEMP SENSOR
AS35
-
EXTERNAL CIRCUIT PROTECTED FROM OVER TEMPERATURE (V+ GOES OFF WHEN TEMP > 125)
OR
RELAY
8.2K
Figure 7. System Over Temperature Protection
Rev. 3/6/03 SPX2950/SPX2951 150mA Low Dropout Voltage Regulator (c)Copyright 2003 Sipex Corporation
11
TYPICAL APPLICATIONS: (Continued)
+5V 4 20mA 8 +V IN V OUT 1N4001 1 4.7mA
UNREGULATED INPUT
OUTPUT
8
IN V OUT
1
330k
2N5432 (2)
SPX2951
0.1F FB 7 2
6
SPX2951
2
27k
V TAP
SENSE FB GND
4 + 7
5V OUTPUT 4.7F LOAD 50mA TO 300 mA
GND 4 360K 1N457 MIN VOLTAGE = 4V
Figure 8. Open Circuit Detector for 4mA to 20mA Current Loop
Figure 9. 300mA Regulator with 0.75V
IN
FEEDBACK R18 20k 3 Q25 Q9 Q3 R11 18k C1 20pF Q4 Q5 R11 20.6k Q2 R8 31.4k Q20 C2 40pF Q21 R12 110k Q11 R13 100 k Q18 R14 350k R13 100k R16 30k Q29 R3 50k R4 13k Q28 6 R21 8 R23 3 Q7 Q8 1 2 Q16 Q17 1 2 Q14 R17 VTAP 12k R28
Q15A
Q15B
24 Q24 Q26 3 OUT SENSE R27
3
Q6 Q1 10
Q42
R1 20k R5 180k Q40 4 R30 30k Q41 R2 50k R6 140k Q13 Q12 R9 27.8k
R10 150 k
Q22 Q23
Q19
R17 10
ERROR Q37 Q36
Q30 R22 150k
Q31 R24 50k 60k
SHDN
Q38 4 R26 60k 2 Q39
Q35
Q34 5 DENOTES CONNECTION ON LP2950 ONLY GND
R25 2.8k
Figure 10. Schematic Diagram
Rev. 3/6/03
SPX2950/SPX2951 150mA Low Dropout Voltage Regulator
(c)Copyright 2003 Sipex Corporation
12
PACKAGE DIAGRAM
8-Pin Surface Mount (S)
1
OUTPUT SENSE SHUTDOWN GROUND
1 2 3 4 8 7 6 5
TO-92 (N) 2 3
INPUT FEEDBACK 5V or 3.3V Output ERROR
V
OUT
V GROUND
IN
SPX2951 Top View
SPX2950 Bottom View
ORDERING INFORMATION Ordering No.
SPX2950ACN-3.3 SPX2950ACN-5.0 SPX2950CN-3.3 SPX2950CN-5.0 SPX2951ACS-3.3 SPX2951ACS-5.0 SPX2951CS-3.3 SPX2951CS-5.0
Accuracy
0.5% 0.5% 1% 1% 0.5% 0.5% 1% 1%
Output Voltage
3.3V 5.0V 3.3V 5.0V 3.3V 5.0V 3.3V 5.0V
Packages
3-Pin TO-92 3-Pin TO-92 3-Pin TO-92 3-Pin TO-92 8-Pin SOIC 8-Pin SOIC 8-Pin SOIC 8-Pin SOIC
Corporation
SIGNAL PROCESSING EXCELLENCE
Sipex Corporation Headquarters and Sales Office 233 South Hillview Drive Milpitas, CA 95035 TEL: (408) 934-7500 FAX: (408) 935-7600
Sales Office 22 Linnell Circle Billerica, MA 01821 TEL: (978) 667-8700 FAX: (978) 670-9001 e-mail: sales@sipex.com
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 herein; neither does it convey any license under its patent rights nor the rights of others. Rev. 3/6/03 SPX2950/SPX2951 150mA Low Dropout Voltage Regulator (c)Copyright 2003 Sipex Corporation
13

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Price & Availability of SPX2951ACS-30

	To Download SPX2951ACS-30 Datasheet File
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