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PJ2950/PJ2951 150mA Low Dropout Voltage Regulators
T
he Semiconductor PJ2950 and PJ2951 are a low power voltage regulators. These devices are excellent choi ce in battery-powered applications such as cordless
The error flag output feature is used as power-on reset for warn of a low output voltage , due to following batteries on input. Other feature is the logic-compatible shutdown input which enable the regulator to be switched on and off. The PJ2950 is offered in 3-pin TO-92 package compatible with other 5 volt regulators. The PJ2951 is available in 8-pin plastic, SOP-8 package. The regulator output voltage may be pin-strapped for a 5 & 3.3 volt of programmed from 1.24 volt to 29 volts with external pai r of resistors. Using of as design, processing and testing techniques make our PJ2950 and PJ2951 superior over similar products.
for use
telephone, radio control systems, and portable computers. The PJ2950 and PJ2951 features very low quiescent current (75A Typ.) and very low drop output voltage (Typ. 40V at light load and 380 mV at 100 mA).This includes a tight initial tolerance of 0.5% typ., extremely good load and line regulation 0.05% typ. and very low output temperature coeffi cient, making the PJ2950/PJ2951 useful as a low-power voltage reference. Other key additional feature of this unregulated input voltage transient of -20V below ground (reverse battery).
____________________________________________________________________________________________________
FEATURES
* * * * * * * * Output accuracy 5V & 3.3V, 150 mA output Very low quiescent current Low dropout voltage Extremely tight load and line regulation Very low temperature coefficient Need only 1F for stability Unregulated DC input can withstand -20V reverse battery and +60V positive transients Direct replacem ent for PJ2950/PJ2951 sockets SOP-8 TO-92 PJ2950/2950A Pin 1. Output 2. Ground 3. Input PJ2951/2951A Pin 1. Output 2. Sense 3. Shutdown 4. Ground 5. Error 6. 5 Vtap 7. Feedback 8. Input
PJ2951 VERSIONS ONLY
* * * Error Flag warns of output dropout Logic-Controlled electronic shutdown Output programmable from 1.24 to 29V
ORDERING INFORMATION
Device
P J2950ACT
APPLICATIONS
* * * * * * * * * *
Operating Temperature
Package TO-92
Battery powered systems Portable instrumentation Avionics Automotive Electronics SMPS Post-Regulator Voltage Reference Portable/Palm top / Notebook computers Portable consumer equipment Radio control systems Cordless telephones
PJ2950CT PJ2950ACT-3.0 PJ2950CT-3.0 PJ2950ACT-3.3 PJ2950CT-3.3 PJ2951ACS PJ2951CS PJ2951ACS-3.3 PJ2951CS-3.3 -20 ~ +85
SOP-8
1-7
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PJ2950/PJ2951 150mA Low Dropout Voltage Regulators
ABSOLUTE MAXIMUM RATINGS
Power Dissipation......................Internally Limited Lead Temp.(Soldering, 5 Seconds)................260 Storage Temperature Range.............-65 to +150 Operating Junction Temperature Range PJ2951............................................. -20 to +125 PJ2950A / PJ2950 PJ2951A / PJ2951............................-20 to +125 Input Supply Voltage............................ -20 to +60V Feedback Input Voltage.........................-1.5 to +30V Shutdown Input Voltage......................... -0.3 to+30V Error Comparator Output........................-0.3 to +30V ECD Rating is to be determined
ELECTRICAL CHARACT ERISTICS at Vs=15V, Ta=25, unless otherwise noted.
CONDITIONS (Note 2) TJ=25 -25 TJ85 Full Operating Temp. 100A IL 100mA TJ TJM AX (Note 1) PJ2950A/PJ2951A Typ Max PJ2950/PJ2951 Typ UNITS
PARAMETER Output Voltage
Min
Min
Max
Output Voltage Output Voltage Temperature Coefficient Line Regulation (Note 3) Load Regulation (Note 3) Dropout Voltage (Note 5) Ground Current
0.995|Vo| 0.990|Vo| 0.988|Vo| 0.986|Vo|
5.0 / 3.3 / 3.0
1.005|Vo| 1.010|Vo| 1.012|Vo| 1.014|Vo|
0.990|Vo| 0.985|Vo| 0.983|Vo| 0.985|Vo|
5.0 / 3.3 / 3.0
1.010|Vo| 1.015|Vo| 1.017|Vo| 1.015|Vo|
V
V
ppm/
20
50
6VVin30V (Note 4) 100AIL 100mA IL =100A IL =100mA IL =150mA IL =100A IL =100mA IL =150mA Vin=4.5V, IL =100A Vout =0 CL =1F CL =200F CL =13.3F (Bypass=0.01F pins 7 to 1 P J2951)
0.03 0.04 40 250 300 75 1.7 4 110 150 0.05 430 160 100
0.2 0.1 80 300 450 120 2.5 6 170 200 0.2
0.04 0.1 40 250 300 75 1.7 4 110 150 0.05 430 160 100
0.2 0.2 80 300 450 120 2.5 6 170 200 0.2
% % mV mV mV
A
mA mA
A
Dropout Ground Current Current Limit Thermal Regulation Output Noise, 10Hz to 100KHz
mA %W
Vms
8-Pin Versions only Reference Voltage Reference Voltage Feedback Pin Bias Current Reference Voltage Temperature Coefficient Feedback Pin Bias Current Temperature Coefficient Over Temperature (Note 6)
PJ2951A
PJ2951
1.238 1.19
1.250
1.262 1.27 40
1.238 1.18
1.250
1.262 1.28 40
V V nA
ppm/
20
(Note 7)
20 50
20
0.1
0.1
nA/
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PJ2950/PJ2951 150mA Low Dropout Voltage Regulators
APPLICATION HINTS EXTERNAL CAPACITORS
CONDITIONS (Note 2) PJ2950A/PJ2951A Min. T yp. Max PJ2950/PJ2951 Min. Typ. Max
PARAMETER
UNITS
Error Comparator Output Leakage Current Output Low Voltage Upper Threshold Voltage Power Threshold Voltage Hysteresis Shutdown Input Output Logic Voltage Shut down Pin Input Current Regulator Output Current in Shutdown
Voh=30V Vin = 4.5V Iol = 400A (Note 8) (Note 8) (Note 8) Low (Regulator ON) High(Regulator OFF) Vs =2.4V Vs = 30V (Note 9)
0.01 150 40 60 75 15 1.3 2 30 450 3
1 250 40 95 150 60 75 15 0.7 2 50 600 10 30 450 3 1.3
1 250
A mV mV
95
mV mV
0.7
V
50 600 10
A A
Note 1: Output or reference voltage temperature coeffi cients defined as the worst case voltage change divided by the total temperature range. Note 2: Unless otherwise specified all limits guaranteed for T j=25, Vin =6V,IL=100A and C L=100F. Additional conditions for the 8-pin versions are feedback tied to 5V & 3.3V tap output Sense (Vout =5V & 3.3V) and Vshutdown 0.8V. Note 3:Regulation is measured Changes in output at constant junction temperature , using pulse testing with a low duty cycle. voltage due to heating effects are convered under the speci fication for therm al regulation. Note 4:Line regulation for the PJ2951 is tested at 150 for IL=1mA.For IL=100A and Tj=125, line regulation is guaranteed by design to 0.2%. See typical 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 value of programmed output voltage , the minimum input performance characteristics for line regulation versus temperature and
supply voltage of taken in to account .
2V (2.3V over temperature) must be
Note 6: Vref Vout (Vin-1V),2.3 Vin 30V, 100A IL 100mA, T J T JMAX.. Note 7: Output or reference voltage temperature coeffi cient is defined as the worst case voltage change divided by the total temperature range. Note 8: 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 For example, at a output is gain=Vout/Vref=(R1+R2)/R2.
programmed output voltage of 5V, the Error
guaranteed to go low when the output drops by 95 mV X 5V/1.250=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 9:Vshutdown 2V, Vin 30V,Vout =0, Feedback pin tied to 5V & 3.3VTap.
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PJ2950/PJ2951 150mA Low Dropout Voltage Regulators
PROGRAMMING THE OUTPUT VOLTAGE OF PJ2951
External Capacitors
For the stability of the less output capacitance is required for stability. For the currents below 10 mA the value of capacitor can be reduce to 0.33 F and 0.1F for 1mA. needed More output capacitance voltage setting with minimum load of 1 A and external resistors. If at the input of PJ2950/LP 2951 connected to battery or between AC filter capacitor and input is 10 inches wire then 1F tantalum or aluminum electrolytic capacitor PJ2950/PJ2951 requires a 1.0 F or greater capacitor between output and ground. Oscillation could occur
without this capacitor. The tantalum or aluminum electrolytic works fine; could use the fiLP type but are not cost effi cient. For the operation of below -25 recommended solid tantalum is since the many
for the 8-pin version at
voltage below 5V since it runs the error amplifi er at lower gain. At worst case 3.3F or greater must be used for condition of 100mA load at 1.250V output . The PJ2950 not like other low dropout regulators will remain stable and regulation with no load in addition to the internal voltage
should be connect ed between input and ground . Instability can occur if stray
aluminum type have electrolytes the freeze at about -30. The ESR of about 5 or less and resonant
capacitor to feedback terminal pin 7 of the PJ2951. This could cues more problem more when using higher
frequency above 500KHz are most important parameter in the value of Capacitor. The Capacitors value can be increas ed without any limit. At lower values of output current,
value of external to set the output voltage . To fix this problem the 100 pF capacitor between output and feedback and increasing output
divider. This feature very important in application like CMOS RAM keep-alive. The PJ2951 output
capacitance to 3.3F.
ERROR DETECTION COMPARATOR OUTPUT
The Compactor produces a logic low output whenever the PJ2951 output falls of regulation by more than around 5% . This is around 60 mV offs et divided by the 1.250 reference voltage. Thus trip remains 5% below nominal regardl ess of the programmed output voltage of the regulator . the figure 1 shows the timing diagram depicting the signal becomes low at around 1.3 V input , it goes high around 5Volt input , (input voltage at which Vout = 4.75). The PJ2951 dropout voltage depending on the load , the input voltage trip point around 5 volt will vary with load current. The output voltage trip point is around 4.75 volt it does not change with load. The error comparator has an opencollector output which requires an external pull-up resistor. Depending requirem ent on the system
the resistor maybe
returned to 5 or 3.3 volt output or other supply voltage depending to the system requirements. For
determining the size of the resistor, note that the output is sinking 400 A , this value adds to battery drain in a low better condition, recommended values 100K to 1M. If the output is unused this resistor is not required.
ERROR signal and the regulator output voltage as the PJ2951 input is ramped up and down . the ERROR
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PJ2950/PJ2951 150mA Low Dropout Voltage Regulators
The PJ2951 output voltage is Refer to the below equation for the programming the output voltage: Volt = Vref x (1+R1 \R2 )+IFB R1 The Vref is 1.250 and IFB is the maybe eliminated at room
programmable for any value from it reference voltage of 1.250 volt and it maximum rating of 30 volt . For example for 5 volt needs to pinstrapped and using the internal
temperature by trimming R1 . To improve the accuracy chooses the value of R2 =100K and this
feedback bias current , nominally -20 nA. The minimum recommended load current of 1A forces an upper limit of 1.2M on value of R 2 , If no load presented the IFB produces error of typically 2% in Vout which
reduces the error by 0.17% and increas es the resistor program
voltage divider by tying pin 1 to 2 and pin 7 to pin 6. Refer to Figure
current by 12 A . The PJ2951 typically draw 60 A at no load with pin 2 open-circuit,and this
2, there are two ext ernal resistor required for this programming .
value does not look much .
REDUCING OUTPUT NOISE
It could be an advantage to reduce the AC noise present at the output One way is to reduce the regulator bandwidth by increasing the value of the output capacitor . this is the only method that noise could reduce on the PJ2950 but is relatively rms . for a 100KHz bandwidth at 5 volt output . Noise could be also reduce by fourfold by a bypass capacitor stability . These changes the output noise from 430V rms . for a 100 kHz bandwidth 5 & 3.3 volt output. With the bypass capacitor added, noise no longer scales with output voltage so that improvements more voltage . dramatic higher are
across R 1 since it reduces the high frequency gain from 4 to unity . pick CBYPASS = 1 / 2R1 x 200Hz or choose 0.01 F . When doing this, the output capacitor must be
output
inefficient
, as increasing capacitor
from 1F to 220F only decreas es the noise from 430V to 160 V
increas ed
to 3.3 F to maintain
FIGURE 1.ERROR OUTPUT TIMING
FIGURE 2.ADJUSTABLE REGULATOR
PJ2951
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2002/01.rev.A
PJ2950/PJ2951 150mA Low Dropout Voltage Regulators
BLOCK DIAGRAM AND TYPICAL APPLICATIONS
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2002/01.rev.A
PJ2950/PJ2951 150mA Low Dropout Voltage Regulators
DIM A B C D F G K M P R
MILLIMETERS MIN MAX 4.80 5.00 3.80 4.00 1.35 1.75 0.35 0.49 0.40 1.25 1.27BSC 0.10 0.25 0 7 5.80 6.20 0.25 0.50
INCHES MIN MAX 0.189 0.196 0.150 0.157 0.054 0.068 0.014 0.019 0.016 0.049 0.05BSC 0.004 0.009 0 7 0.229 0.244 0.010 0.019
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