SIPEX LP2950CN-3.3

LP2950/LP2951
100mA Low Dropout Voltage Regulators
FEATURES
APPLICATIONS
• 5.0V and 3.3V Versions at 100mA Output
• Very Low Quiescent Current
• Low Dropout Voltage: 380mV at 100mA
• Extremely Tight Load and Line Regulation
• Very Low Temperature Coefficient
• Current & Thermal Limiting
• Need Only 1 µF for Stability
• Offered in TO-92 (LP2950) & SOIC (LP2951)
• Direct Replacement For LP2950/LP2951
• 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
LP2951 versions only
• Error Flag Warns of Output Dropout
• Logic-Controlled Electronic Shutdown
• Output Programmable From 1.24 to 29V
Now Available in Lead Free Packaging
PRODUCT DESCRIPTION
The LP2950 and LP2951 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 LP2950 and LP2951 feature low
quiescent current and low dropout voltage (typ. 50mV at light load and 380 mV at 100mA). This includes a tight initial tolerance
(0.5% typ.), extremely good load and line regulation (0.05% typ.), and very low output temperature coefficient (20 ppm/¡C typ.),
making the LP2950/LP2951 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 input voltage. The logiccompatible shutdown feature enables the regulator to be switched ON and OFF. The LP2950 is offered in a 3-pin TO-92 package
compatible with other 5V, 3.3V regulators. The LP2951 is available in an 8-lead SOIC package.
Block diagram of LP2951
UNREGULATED DC
8
1
INPUT
OUTPUT
7
+
FEEDBACK
5V @ 100mA
MAX
2
SENSE
+
_
FROM
CMOS OR
TTL
3
180kΩ
6
ERROR
AMPLIFIER
330kΩ
5V TAP
SHUTDOWN
+
60kΩ
60 mV
+
5
______
+
_
+ 1.23V
ERROR
ERROR DETECTION
COMPARATOR
1µF
.
.
TO CMOS OR
TTL
4
REFERENCE
Rev. 8/10/01
GROUND
LP2950/51 100mA Low Dropout Voltage Regulators
1
©Copyright 2001 Sipex Corporation
LP2950/51
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
-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 VIN=6V, IO=100µA, COUT=1µF (Note 2) TA=25C, unless otherwise noted.
PARAMETER
3.3 V Versions
Output Voltage
Output Voltage
5 V Versions
Output Voltage
Output Voltage
CONDITIONS
TJ = 25¡C
-25¡C ≤TJ ≤85¡C
Full Operating Temperature
100 µA ≤IL ≤100 mA
TJ ≤TJMAX
TJ = 25¡C
-25¡C ≤TJ ≤85¡C
Full Operating Temperature
100 µA ≤IL ≤100 mA
TJ ≤TJMAX
LP2950AC
LP2951AC
Min.
Typ. Max.
Min.
LP2950C
LP2951C
Typ. Max.
UNITS
3.284
3.267
3.260
3.3
3.3
3.3
3.317
3.333
3.340
3.267
3.251
3.234
3.3
3.3
3.3
3.333
3.350
3.366
V
3.254
3.3
3.346
3.221
3.3
3.379
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
20
120
50
150
ppm/¡C
V
All Voltage Options
Output Voltage
Temperature Coefficient
Line Regulation (Note 3)
(Note 1)
6V ≤VIN ≤30V (Note 4)
0.03
0.1
0.04
0.2
%
Load Regulation (Note 3)
100 µA ≤IL ≤ 100 mA
0.04
0.1
0.1
0.2
%
Dropout Voltage
(Note 5)
IL = 100 µA
IL = 100 mA
IL = 100 µA
IL = 100 mA
50
380
80
450
50
380
80
450
mV
mV
150
8
170
12
150
8
170
12
µA
mA
150
200
150
200
mA
0.05
0.2
0.05
0.2
%/W
Ground Current
Current Limit
VOUT = 0
Thermal Regulation
Output Noise,
CL = 1µF
430
430
µV rms
10Hz to 100KHz
CL = 200 µF
160
160
µV rms
CL = 3.3 µF, Bypass = 0.01µF
from Pin 7 to Pin 1 (LP2951)
100
100
µV rms
8-Pin Versions only
Reference Voltage
Reference Voltage
Feedback Pin Bias
Current
Rev. 8/10/01
Over Temperature (Note 6)
1.220
LP2951AC
1.235
1.250
1.210
LP2951C
1.235
1.260
V
1.190
1.270
1.185
1.285
V
40
60
40
LP2950/51 100mA Low Dropout Voltage Regulators
2
60
nA
©Copyright 2001 Sipex Corporation
LP2950/51
PARAMETER
8-Pin Versions only (Continued)
CONDITIONS
(Note 2)
Min.
Reference Voltage
Temperature
Coefficient
Feedback Pin Bias
Current
Temperature Coefficient
Error Comparator
LP2951AC
Typ. Max.
Min.
LP2951C
Typ. Max.
UNITS
20
50
ppm/¡C
0.1
0.1
nA/¡C
Output Leakage Current
VOH = 30V
0.01
1
0.01
1
µA
Output Low Voltage
VIN = 4.5V
IOL = 400µA
(Note 7)
150
250
150
250
mV
Upper Threshold
Voltage
Lower Threshold
Voltage
Hysteresis
40
60
(Note 7)
75
(Note 7)
15
40
95
60
75
mV
95
15
mV
mV
Shutdown Input
Input logic Voltage
Shut down Pin Input
Current
Regulator Output
Current in Shutdown
Low (Regulator ON)
High (Regulator OFF)
VS = 2.4V
VS= 30V
(Note 8)
1.3
0.7
2.0
1.3
0.7
30
675
3
50
800
10
2.0
30
675
3
50
800
10
V
V
µA
µA
µA
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 guaranteed for TJ = 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 (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 LP2951 is tested at IL = 1mA. For IL = 100 µA 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≤ 100mA, 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 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 Tap.
Note 9: All typical values are not guaranteed. The value could vary from lot to lot.
Rev. 8/10/01
LP2950/51 100mA Low Dropout Voltage Regulators
3
©Copyright 2001 Sipex Corporation
LP2950/ LP2951
TYPICAL PERFORMANCE CHARACTERISTIC
10
250
6
225
R L=
3
R L =50kΩ
2
GROUND PIN CURRENT (mA)
4
R L = 50kΩ
175
150
125
100
RL =
8
INPUT CURRENT (µA)
200
8
OUTPUT VOLTAGE (VOLTS)
5
75
50
1
1
0.1
25
0
0
1
2
3
4
5
1
0
6
2
320
240
INPUT CURRENT (mA)
GROUND CURRENT (µA)
280
I L = 1mA
200
160
IL= 0
120
80
40
1
2
3
5
6
7
8
4
5
0.01
0.1
9 10
6
7
R L =50 Ω
VOUT = 5V
12
V IN = 6V
I L = 100mA
8
4
1
2
3
4
5
6
7
8
-75 -50 -25
9 10
0
25 50
75 100 125 150
TEMPERATURE (ºC)
INPUT VOLTAGE (VOLTS)
Ground Current
100
16
0
INPUT VOLTAGE (VOLTS)
10
Quiescent Current
160
150
140
130
120
110
100
90
80
70
60
50
40
30
20
10
0
8
1
LOAD CURRENT (mA)
Input Current
Dropout Characteristics
0
4
INPUT VOLTAGE (VOLTS)
INPUT VOLTAGE (VOLTS)
0
3
GROUND CURRENT (mA)
0
Ground Current
Input Current
16
190
12
10
QUIESCENT CURRENT (µA)
GROUND CURRENT (mA)
14
I L =100mA
8
6
4
170
V IN =6V
I L =100uA
150
130
2
0
0
1
2
3
4
5
6
7
-75 -50 -25
8
INPUT VOLTAGE
Ground Current
Rev. 8/10/01
0
25 50
75 100 125 150
TEMPERATURE (ºC)
Quiescent Current
LP2950/51 100mA Low Dropout Voltage Regulators
4
©Copyright 2001 Sipex Corporation
LP2950/LP2951
TYPICAL PERFORMANCE CHARACTERISTICS (continued)
170
500
600
I L = 100mA
160
400
300
~
~
100
50
I L = 100µA
SHORT CIRCUIT CURRENT (mA)
400
DROP-OUT VOLTAGE (mV)
300
200
TJ = 25ºC
100
0
0
-75 -50 -25
0
25 50
100µA
75 100 125 150
1mA
TEMPERATURE (ºC)
10mA
140
130
120
110
110
-75 -50 -25
100mA
OUTPUT CURRENT
Drop-Out Voltage
2.5
T A = 125ºC
SINK CURRENT (mA)
HYSTERESIS
2
0
50
mV
1.5
T A = 25ºC
1.0
T A = -55ºC
0.5
0.0
0
1
2
3
4
5
0
C L = 1µF
I L = 1mA
V OUT = 5V
-50
mV ~
~
8V
6V
PULLUP RESISTOR TO
SEPARATE 5V SUPPLY
-2
4V
0
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9
INPUT VOLTAGE (V)
200
OUTPUT LOW VOLTAGE (V)
Error Comparator Output
400
600
800
TIME(µs)
LP2951 Comparator Sink Current
10
75 100 125 150
100
mV
2.0
4
25 50
Short Circuit Current
V OUT = 5V
6
0
TEMPERATURE (ºC)
Drop-Out Voltage
8
COMPARATOR OUTPUT (V)
150
INPUT OUTPUT VOLTAGE
VOLTAGE CHANGE
DROP-OUT VOLTAGE (mV)
500
Line Transient Response
90
90
80
80
I O = 1mA
2
I O = 100mA
1
0.5
V OUT = 5V
C L = 1µF
0.2
0.1
0.05
70
IL = 0
60
50
40
I L = 100µA
C L = 1µF
V IN = 6V
V OUT = 5V
30
0.02
RIPPLE REJECTION (dB)
5
RIPPLE REJECTION (dB)
OUTPUT IMPEDANCE (OHMS)
IO = 100µA
10
100
1K
10K
FREQUENCY (Hz)
Output Impedance
Rev. 8/10/01
100K
1M
I L = 1mA
60
50
40
30
20
0.01
70
C L = 1µF
V IN = 6V
V OUT = 5V
I L = 10mA
20
10
1
10
2
10
3
10
4
10
5
10
10 1
6
FREQUENCY (Hz)
Ripple Rejection
10 2
10 3
10 4
10 5
10 6
FREQUENCY (Hz)
Ripple Rejection
LP2950/51 100mA Low Dropout Voltage Regulators
5
©Copyright 2001 Sipex Corporation
LP2950/LP2951
TYPICAL PERFORMANCE CHARACTERISTICS (continued)
20
50
1.9
FEEDBACK CURRENT (µA)
2.1
0
-10
-20
-50 -25
0
25
50
-75 -50 -25
75 100 125 150
0
25 50
6
150
40
100
20
-50
C L = 1µF
V OUT = 5V
100
mA
0
-20
C L = 10µF
V OUT = 5V
-40
-60
~
~
100
µA
100
100
µA
µA
2
3
4
5
0
4
8
12
16
T JMAX = 125 ºC
40
T A =25 ºC
T A = 85 ºC
20
5
10
15
20
INPUT VOLTAGE (V)
LP2950 Maxium Rated Output
25
I L = 10mA
V IN = 8V
V OUT = 5V
1
C L = 10µF
0
2
0
0 100 200 300 400 500 600 700
Enable Transient
120
100
30
DIP SOLDERED
TO PC BOARD
T JMAX = 125º C
V OUT = 5V
300
200
100
80
60
T A = 25ºC
40
T A = 50ºC
20
0
0
0
2
TIME (us)
OUTPUT CURRENT (mA)
Vout=5V
60
3
8-PIN
MOLDED
PIN 2 TO PIN 4 RESISTANCE (kΩ)
80
4
-100
400
TO-92 PACKAGE
0.25" LEADS SOLDERED
TO PC BOARD
100
5
20
Load Transient Response
120
1.0
C L = 1µF
TIME (ms)
Load Transient Response
0.5
-2
TIME (ms)
Rev. 8/10/01
SHUTDOWN OUTPUT
PINOUT VOLTAGE (V) VOLTAGE (V)
7
0
0
-0.5
LP2951 Feedback Pin Current
80
50
-1.0
FEEDBACK VOLTAGE (V)
60
1
-1.5
-2.0
250
0
T A = 55ºC
-200
200
~
~
T A = 25ºC
-150
75 100 125 150
LP2951 Feedback Bias Current
LOAD OUTPUT VOLTAGE
CURRENT CHANGE (mV)
LOAD OUTPUT VOLTAGE
CURRENT CHANGE (mV)
LP2951 Minimum Operating Voltage
-100
TA=1 25ºC
-100
TEMPEATURE (ºC)
TEMPERATURE
OUTPUT CURRENT (mA)
-50
-250
-30
1.7
-75
PIN 7 DRIVEN BY EXTERNAL
SOURCE (REGULATOR RUN
OPEN LOOP)
0
10
BIAS CURRENT (nA)
MINIMUM OPERATING VOLTAGE (V)
2.3
-75
T A = 85ºC
0
-50 -25
0
25
50
75 100 125 150
0
TEMPERATURE (ºC)
LP2951 Divider Resistance
10
15
20
25
30
INPUT VOLTAGE (V)
LP2950 Maxium Rated Output Current
LP2950/51 100mA Low Dropout Voltage Regulators
6
5
©Copyright 2001 Sipex Corporation
LP2950/LP2951
3.5
1.6
4
3.0
1.4
1.2
VOLTAGE NOISE
SPECTRAL DENSITY (µV/Hz)
5
OUTPUT VOLTAGE
CHANGE (mV)
1.8
2
0
-2
1.0
POWER
DISSIPATION (W)
SHUTDOWN THRESHOLD VOLTAGE (V)
TYPICAL APPLICATIONS
0.8
0.6
-75 -50 -25
0
25
50
~~
1
1.25W
C L = 220µF
2.0
1.0
10
20
30
40
50
10 2
TIME (µs)
Shutdown Threshold Voltage
C L = 3.3µF
C BYP = 0.1µF
1.5
0.0
-1
TEMPERATURE (¼C)
10 3
10 4
10 5
FREQUENCY (Hz), C BYP =0.1uF
Thermal Response
Output Noise
80
30
I L = 50µA
25
20
70
I L = 100µA
15
T J = 150 ¼C
10
5
RIPPLE REJECTION (dB)
OUTPUT VOLTAGE CHANGE (mV)
C L = 1µF
2.5
0.5
0
0
75 100 125 150
I L = 100mA
I L = 1mA
0
~~
10
5
0
T J = 125 ¼C
I L = 100µA
60
I L = 100mA
50
40
C L = 1µF
V IN = 6V
V OUT = 5V
30
20
-5
10
-10
5
10
15
20
25
30
10 1
10 2
INPUT VOLTAGE (V)
10 4
10 5
10 6
FREQUENCY (Hz)
Line Regulation
Rev. 8/10/01
10 3
Ripple Rejection
LP2950/51 100mA Low Dropout Voltage Regulators
7
©Copyright 2001 Sipex Corporation
LP2950/51
APPLICATION HINTS
EXTERNAL CAPACITORS
The stability of the LP2950/LP2951 requires a 1.0µF 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 -25°C solid tantalum is recommended
since the many aluminum types have electrolytes that 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 capacitors value may be increased without limit.
remains 5% below normal regardless of the programmed output
voltage of the regulator.
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 0.33µ F and 0.1µ F 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 3.3 µF or
greater must be used for the condition of 100mA 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 400µ A, 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 LP2950/51 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
LP2950/51 version with external resistors, a minimum load of 1µA is
recommended
PROGRAMMING THE OUTPUT VOLTAGE OF LP2951
The LP2951 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:
Figure 1 shows the timing diagram depicting the ERROR signal and
the regulator output voltage as the LP2951 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 LP2951Õs 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.
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.
VOUT = VREF × (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 µA forces an
upper limit of 1.2MΩ 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 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 LP2951
typically draws 60µA at no load with Pin 2 open-circuited this is a
small price to pay
Instability can occur if there is stray capacitance to the LP2951
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 3.3
µF.
4.75V
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 LP2950 but is relatively inefficient, as increasing the
capacitor from 1µF to 220 µF only decreases the noise from 430µV
to 160µVRMS 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
_______
ERROR*
+5.0V
INPUT
VOLTAGE
+1.3V
+
CBYPASS ≅ 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.
* See Application Info.
Figure 1. ERROR Output Timing
ERROR DETECTION COMPARATOR OUTPUT
The Comparator produces a logic low output whenever the LP2951
output falls out of regulation by more than around 5%. This is around
60 mV offset divided by the 1.235 reference voltage. This trip level
Rev. 8/10/01
9
LP2950/51 100mA Low Dropout Voltage Regulators
8
©Copyright 2001 Sipex Corporation
LP2950/LP2951
TYPICAL APPLICATIONS
+V IN
100K
8
ERROR
5
OUTPUT
+V IN
______
ERROR
V OUT
1.2 to 30V
1
LP2951
SHUTDOWN
SD
INPUT
+
R1
3
FB
GND
3.3µF
.01µF
7
4
1.23V
R2
V REF
Figure 2. Adjustable Regulator
+V
IN
470kΩ
8
5
______
ERROR
+V
+V
IN
+V
IN
IN
V OUT
470kΩ
V OUT
1
8
ERROR
LP2951
5
OUTPUT
______
ERROR
V OUT
1
*V OUT = V
IN
+
3
RESET
R1
SD
GND
4
LP2951
1µF
FB
SHUTDOWN
7
INPUT
3
SD
GND
4
R2
*MINIMUM INPUT-OUTPUT VOLTAGE RANGES FROM 40mV to 400mV.
DEPENDING ON LOAD CURRENT. CURRENT LIMIT IS TYPICALLY 150mA
Figure 3. Latch Off When Error Flag Occurs
Rev. 8/10/01
FB
7
Figure 4. Wide Input voltage Range Current Limiter
LP2950/51 100mA Low Dropout Voltage Regulators
9
©Copyright 2001 Sipex Corporation
LP2950/LP2951
TYPICAL APPLICATIONS (continued)
+
6V
SEALED
LEADACID
BATTERY
SOURCE
1.5kΩ
120kΩ
8
1N457
+V IN
FB
SPX385
V OUT
1
MAIN V+
LP2951
MEMORY V+
SENSE
400kΩ
FOR 5.5 V
3
2
1µF
SD
100kΩ
+
GND
20kΩ
NI-CAD
BACKUP
BATTERY
4
Figure 5. Low Battery disconnect
8
39kΩ ..
2
SENSE
+VIN
5 ______
ERROR
RESET
-
+
3
C4
+
1uF
LP2951
SD
FB
39kΩ ..
1%
+VOUT = 5V
1
VOUT
GND
4
100kΩ ..
7
TAP
6
100kΩ ..
C1
6V
LEADACID
BATTERY
1%
1kΩ ..
+
<5.8V**
100kΩ ..
C2
+
1%
1kΩ ..
<6.0V**
100k Ω ..
C3
+
R3
1%
<6.2V**
10k Ω ..
20k Ω ..
* OPTIONAL LATCH OFF WHEN DROPOUT OCCURS. ADJUST R3 FOR C2 SWITCHING WHEN
VIN IS 6.0V
* OUTPUTS GO LOW WHEN V IN DROPS BELOW DESGNATED THRESHHOLDS
Figure 6. Regulator with State-of Charge Indicator
Rev. 8/10/01
LP2950/51 100mA Low Dropout Voltage Regulators
10
©Copyright 2001 Sipex Corporation
LP2950/LP2951
TYPICAL APPLICATIONS (continued)
+V IN
8
3
AUX SHUTDOW
INPUT
10K Ω.
+V IN
_______
ERROR
SD
OFF
5 DEGREE SHUTDOWN FLAG
.
LP2951
ON
V OUT
GND
1
FB
4
+
TEMP
SENSOR
5
EXTERNAL CIRCUIT
PROTECTED FROM
OVER TEMPERATURE
(V+ GOES OFF WHEN
TEMP > 125)
7
AS35
OR
RELAY
8.2K Ω
-
Figure 7. System Over Temperature Protection
+5V
4
UNREGULATED INPUT
4.7mA
20mA
8
OUTPUT
8
IN
+V IN
V OUT
1
330K Ω
27KΩ
LP2951
1N4001
LP2951
0.1µF
FB
7
5V
2
6
SENSE
V TAP
2
GND
4
2N5432
(2)
V OUT
1
FB
GND
7
4
OUTPUT
+
360K Ω
1N457
4.7µF
LOAD
50mA
TO
300 mA
MIN VOLTAGE = 4V
Figure 8. Open Circuit Detector for 4mA to 20mA Current
Loop
Rev. 8/10/01
Figure 9. 300mA Regulator with 0.75V
LP2950/51 100mA Low Dropout Voltage Regulators
11
©Copyright 2001 Sipex Corporation
LP2950/LP2951
SCHEMATIC DIAGRAM
Rev. 8/10/01
LP2950/51 100mA Low Dropout Voltage Regulators
12
©Copyright 2001 Sipex Corporation
LP2950/LP2951
PACKAGE DIAGRAM
8-Pin Surface Mount (S)
TO-92 (N)
2
1
OUTPUT
1
SENSE
2
SHUTDOWN
GROUND
8
INPUT
ALPHA
7
FEEDBACK
3 AS293
6
5V or 3.3V Output
4 0
5
ERROR
V
3
VIN
OUT
GROUND
LP2950 Bottom View
LP2951 Top View
ORDERING INFORMATION
Ordering No.
Accuracy
Output Voltage
LP2950ACN-3.3
LP2950ACN-5.0
LP2950CN-3.3
LP2950CN-5.0
LP2951ACS-3.3
LP2951ACS-5.0
LP2951CS-3.3
LP2951CS-5.0
0.5%
0.5%
1%
1%
0.5%
0.5%
1%
1%
3.3V
5.0V
3.3V
5.0V
3.3V
5.0V
3.3V
5.0V
Corporation
Packages
3 lead TO-92
3 lead TO-92
3 lead TO-92
3 lead TO-92
8 Lead SOIC
8 Lead SOIC
8 Lead SOIC
8 Lead SOIC
Now available in Lead Free. To order ad "-L" to the part number.
Example: LP2950CN= Normal, LP2950CN-L = Lead Free
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: [email protected]
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. 8/10/01
LP2950/51 100mA Low Dropout Voltage Regulators
13
©Copyright 2001 Sipex Corporation