100mA Low Dropout
Voltage Regulators
LP2950 / LP2951
FEATURES
••5V, 3. 3V, and 3.0V Versio ns at 100mA Out pu t
••Very Low Q ui escent Cur rent
••Low Dropout Voltage
••Extr em ely Tig h t Load and Line Regulat io n
••Very Low Tem pe ratur e Coef f ici ent
••Current and Thermal Limiting
••Needs Only 1µF fo r Stabi l ity
LP2951 V ersions On ly
••Error Fl ag Warns of O ut put Dropout
••Logic-Controlled Electronic Shutdown
••Out p u t Progr am ma bl e from 1. 24 to 29 V
APPLICATIONS
••Batt er y Power ed Syst em s
••Cordless Telephones
••Radio Control Syst ems
••Port able / Palm Top / Noteboo k Comput ers
••Portable Cons umer Equipment
••Port abl e Inst ru me nt at io n
••Avionics
••SMPS Post -Regu lato r
••Volt age Ref er enc e
••Aut om ot i ve El ect ronics
PRODUCT DESCRI PTI ON
The Calogic 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 features very low quiescent current and very low
drop out volt age (Typ. 50mV at light load and 380mV at 100mA).
This includes a tight initial tolerance of 0.5% typ., extremely
good load and l ine regulation 0.05% typ. and very low output
temperature coefficient, making the LP2950/LP2951 useful
as a low- powe r voltage refere nce.
The error flag output feature is used as power-on reset for
warning of a low output voltage, due to falling voltage input o f
batteries. Another feature is the logic-compatible shutdown
input which enables the regulator to be switched on and off.
The LP2950 is offered in a 3-pin TO-92 package compatible
with other 5V, 3.0V, 3.3V regulators. The LP2951 is also av ailabl e
in 8-pin plast ic and SO - 8.
The regulator output vol tage may be pin-strapped for 5V, 3V
or 3.3 volts or programmed from 1.24 volt to 29 volts with an
extern al pair of r esistors. Use of AS’s design, processing an d
testing techniques make our LP2950 and LP2951 superior
over similar pro ducts.
ORDERING INFORMAT ION
PART P ACKAG E TEMPERATURE RANGE
LP2950ACN-X TO-92 (3-Pin) IND.
LP2950CN-X TO-92 (3-Pin) IND.
LP2951ACP-X Plastic DIP (8-Pin) IND.
LP2951CP-X Plastic DIP (8-Pin) IND.
LP2951ACS-X Plastic SOIC (8-Pin) IND.
LP2951CS-X Plastic SOIC (8-Pin) IND.
X = 3.0V, 3.3V or 5.0V
CORPORATION
PIN CONNECTI O NS
1D-20
123 1. OUTPUT
2. GROUND
3. INPUT
TO-92
BOTTOM VIEW
GROUND
1
2
3
8
7
6
4 5 ERROR
LP2951
1D-19
8-PIN SURFACE MOUNT
5V OR 3.3V TAP
FEEDBACK
INPUT
SHUTDOWN
SENSE
OUTPUT
TOP VIEW
CALOGIC COR PORATION, 237 Whitn ey Place, Fremont, California 9453 9, Telephone: 510 -656- 2900, FAX: 510-65 1-3025
ABSOLUTE M AXIM UM R A T INGS
Power Dissipat ion . . . . . . . . . . . . . . . . . . . . . Int ernally Limited
Lead Temp. ( Solder ing, 5 Seconds) . . . . . . . . . . . . . . . 260oC
Stor age Temper at ure R a nge. . . . . . . . . . . . . . . -65 t o +150oC
Oper ating Ju nct ion Te mper at ure Ran ge
LP2951. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -55 to +150oC
LP2950AC/LP2950C
LP2951AC/ LP29 51C . . . . . . . . . . . . . . . . . . . -40 to +125oC
Input Supply V o ltag e . . . . . . . . . . . . . . . . . . . . . . -0.3 to +30 V
Feedbac k Input Voltage. . . . . . . . . . . . . . . . . . . . -1.5 to +30V
Shutd own In put Voltage. . . . . . . . . . . . . . . . . . . . -0.3 to +30V
Error Comparator Ou tput. . . . . . . . . . . . . . . . . . . -0.3 to +30V
ESD Ratin g . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2KV Min
LP2950 / LP2951
CORPORATION
CALOGIC COR PORATION, 237 Whitn ey Place, Fremont, California 9453 9, Telephone: 510 -656- 2900, FAX: 510-65 1-3025
ELECTRICA L CHARACTERI STICS: VS = 15V, TA = 25oC, unles s otherwise spe cified.
PARAMETER LP2951 LP2950 AC / LP29 51 AC LP2950C / LP2951C UNITS CONDITIONS
(Note 2)
MIN TYP MAX MIN TYP MAX MIN TYP MAX
3V VERSIONS
Output Voltage 2.985
2.964
3.0 3.015
3.036
2.985
2.970
2.964
3.0
3.0
3.0
3.015
3.030
3.036
2.970
2.955
2.940
3.0
3.0
3.0
3.030
3.045
3.060
V
V
V
TJ = 25oC
-25oC ≤ TJ ≤ 85oC
Full Operating Temperature
Output Voltage 2.955 3.0 3.045 2.958 3.0 3.042 2.928 3.0 3.072 V 100µA ≤ IL ≤ 100mA
TJ ≤TJMAX
3.3V VERSIONS
Output Voltage 3.284
3.260
3.3 3.317
3.340
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
V
V
TJ = 25oC
-25oC ≤ TJ ≤ 85oC
Full Operating Temperature
Output Voltage 3.251 3.3 3.350 3.254 3.3 3.346 3.221 3.3 3.379 V 100µA ≤ IL ≤ 10 0mA
TJ ≤TJMAX
5V VERSIONS
Output Voltage 4.975
4.94
5.0 5.025
5.06
4.975
4.95
4.94
5.0
5.0
5.0
5.025
5.050
5.06
4.95
4.925
4.90
5.0
5.0
5.0
5.05
5.075
5.10
V
V
V
TJ = 25oC
-25oC ≤ TJ ≤ 85oC
Full Operating Temperature
Output Voltage 4.925 5.0 5.075 4.93 5.0 5.07 4.88 5.0 5.12 V 100µA ≤ IL ≤ 10 0mA
TJ ≤ TJMAX
ALL VOLTAGE OPTIONS
Output Voltage
Temperature Coefficient 20 120 20 50 ppm/oC (Note 1)
Line Regulation (Note 3) 0.03 0.1 0.03 0.1 0.04 0.2 % 6V ≤ VIN ≤ 30V (Note 4)
Load Regulation (Note 3) 0.04 0.1 0.04 0.1 0.1 0.2 % 100µA ≤ IL ≤ 10 0mA
Dropout Voltage
(Note 5) 50
380 80
450 50
380 80
450 50
380 80
450 mV
mV IL = 100µA
IL = 100mA
Ground Current 150
8170
12 150
8170
12 150
8170
12 µA
mA IL = 100µA
IL = 100mA
Current Limit 130 200 130 200 130 200 mA VOUT = 0
Thermal Regulation 0.05 0.2 0.05 0.2 0.05 0.2 %/W
Output Noise,
10Hz to 100KHz
430
160
100
430
160
100
430
160
100
µVrms
µVrms
µVrms
CL = 1µF
CL = 200µF
CL = 13.3µF
(Bypass = 0.01µF pins 7 to 1 (LP2951 ))
8-PIN VERSIONS ONLY LP2951 LP2951AC LP2951C
Reference Vol tage 1.22 1.235 1.25 1.22 1.235 1.25 1.21 1.235 1.26 V
Reference Voltage 1.19 1.27 1. 19 1.27 1.185 1.285 V Over Temperature (Note 6)
Feedback Pin Bias Current 40 60 40 60 40 60 nA
Reference Vol tage
Temperature Coefficient 20 20 50 ppm/oC (Note 7)
Feedback Pin Bias Current
Temperature Coefficient 0.1 0.1 0.1 nA/oC
LP2950 / LP2951
CORPORATION
BLOC K DIAG RAM
ERROR DETECTION
COMPARATOR
1D-21
1µF
REFERENCE
1.23V
UNREGULATED DC
ERROR
AMPLIFIER
60mV +
+TO CMOS OR
TTL
330kΩ
FROM
CMOS
OR TTL
+
+
5V @ 100mA
MAX
60kΩ
LP2950 AND LP2951 BLOCK DIAGRAM
180kΩ
817
SENSE
6
2
4
5
5V TAP
ERROR
GROUND
INPUT OUTPUTFEEDBACK
SHUTDOWN
3
–
+
–
+
CALOGIC COR PORATION, 237 Whitn ey Place, Fremont, California 9453 9, Telephone: 510 -656- 2900, FAX: 510-65 1-3025
ELECTRICA L CHARACTERI STIC S (continued)
PARAMETER LP2951 LP2950 AC / LP29 51 AC LP2950C / LP2951C UNITS CONDITIONS
(Note 2)
MIN TYP MAX MIN TYP MAX MIN TYP MAX
ERROR COMPARATOR
Output Leakage Current 0.01 1 0.01 1 0.01 1 µAV
OH = 30V
Output Low Voltage 150 250 150 250 150 250 mV VIN = 4.5V, IOL = 400µA
Upper Threshold Volt age 4 0 60 40 60 40 60 mV (Note 7)
Lower Threshold V oltage 75 95 75 95 75 95 mV (Note 7)
Hysteresis 15 15 15 mV (Note 7)
SHUTDOWN INPUT
Input Logic Voltage 21.3 0.6 21.3 0.7 21.3 0.7 V
VLow (Reg ula to r ON)
High (Regulator OFF)
Shutdown Pin
Input Current 30
675 50
800 30
675 50
800 30
675 50
800 µA
µAVS = 2.4V
VS = 30V
Regulator Output Current
in Shutdown 310 310 310 µA (Note 9)
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 = 25oC, VIN = 6V, IL=100µA and C L = 1µF. Additional conditions for the 8-pin
version s are feedba ck tie d to 5V t ap an d outpu t t ied to output Sen se (VOUT = 5V) and VSHUTDOW N ≤ 0.8V.
Note 3: Regulation is measured at constant junction temperature, using pulse testin g 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 150oC for IL = 1mA. For IL = 100µA and TJ = 125oC, lin e reg ula tio n is guara nte ed by d esig n 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 100mV below its nominal value measure d
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 input 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
mea su red at 6V inpu t. To express th ese thre sh old s in term s of outp ut vo ltage chan ge , mu ltip ly by th e error amp lifier gai n = 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. 23 5 = 38 4mV. Thresho lds rema in consta nt as a pe rcent 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.
APPLICATION HINTS
EXTERNAL CA PACITOR S
•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 are acceptable. For operations
below -25oC a solid tantalum is recommended since the
many aluminum types have electrolytes that freeze at about
-30oC. The ESR of about 5Ω or less and resonant
frequency about 500kHz ar e the most imp orta nt par am eter s
in the value of the capaci tor. The capacitors value may be
increas ed with out limit .
•At lower va lues of output curr ent, less output cap acitance i s
required for stability. For currents below 10mA the value of
the capacitor can be reduced to 0.33µF and 0.1µF 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 3.3µF or greater must be used for the
condition of 100mA load at 1.23V out pu t.
•The LP2950, unlike oth er low dropout reg ulators will remain
stable and in regulation with no load in addition to the
internal voltage divider. This feature is especially important
in applications l ike CMOS RAM keep-al ive ci rcui ts. When
setting the output voltage of the LP2951 version with
externa l resist or s, 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 batt ery is used as t he input
then a 1µA tantalum or aluminum electrolytic capacitor
should be place d fr om the input to the groun d.
•Instability can occur if there is a 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 eliminated by
adding a 100pF capacitor between output and feedback
and incre asing the ou tp ut capac itor to at least 3.3µF.
ERROR DETECTI ON COMPARATO R OUTPUT
The Comparator produces a logic low output whenever the
LP2951 output falls out of reg ulat io n by mo re than ar ou nd 5% .
This occurs at approximately 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
LP2951 input is ramped up and down. The ERROR signal
becomes low at around 1.3V input , and goes high around 5V
inpu t ( input volt age at which VOUT = 4. 75). Si nc e the LP2951’s
dropout voltage is load dependent, the input voltage trip point
(around 5V) will vary w ith the load cur rent . The outpu t vo ltag e
trip po in t (appro x. 4 .75V) does no t vary with load.
The error comparator has an open-collector output which
requires an extern al pullup resistor. Depe nding o n the sy stem
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 re quir ed.
PROGRAMMING THE OUTPUT VOLTAGE OF LP2951
The LP2951 may be pin-strapped for 5V using its internal
voltage divider by t ying Pin 1 ( out pu t) to Pin 2 (se nse) and Pin
7 (feedback) to Pin 6 (5V Tap). Also, i t 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
resist or s is requir ed.
Refer to the equation below for the program m ing of the o ut put
voltage:
V
OUT = VREF × (1 + R1\R2) + IFBR1
The VREF is 1.235 and IFB is the feedback bias current,
nominally -20nA. The minim um r ecom me nded load curren t of
1µA forces an upper limit of 1.2MΩ on value of R2. If no l oad
is presented the IFB produces an error of typically 2% in VOUT
wh ich may be elimi na te d at room te m per at ur e by trimm ing 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-ci rcuited this i s 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 no ise can be reduced on the lead 3 of LP2950, b ut is
relatively inefficient, as increasing the capacitor from 1µF to
220µF only decreases the noise from 430µV to 160µVrms fo r
a 100kHz ban dwidt h at 5V o utput .
Noise could also be reduced fourfold by a bypass capacitor
across R1, since i t reduces the high frequency gain from 4 to
unity.
C
BYPASS ≅ 1/ 2πR1 × 200Hz
or choose 0.01µF. W he n doing this , the outpu t capacit or 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
impr ovem e nt s are mor e dram at ic at higher volt ages .
LP2950 / LP2951
CORPORATION
CALOGIC COR PORATION, 237 Whitn ey Place, Fremont, California 9453 9, Telephone: 510 -656- 2900, FAX: 510-65 1-3025
LP2950 / LP2951
CORPORATION
CALOGIC COR PORATION, 237 Whitn ey Place, Fremont, California 9453 9, Telephone: 510 -656- 2900, FAX: 510-65 1-3025
LOAD CURRENT (mA)
10
0.01
0.1 100
1D-22
QUIESCENT CURRENT
GROUND PIN CURRENT (mA)
0.1
1
1.0 10 INPUT VOLTAGE (VOLTS)
250
0010
1D-24
INPUT CURRENT
INPUT CURRENT (µA)
5 6 7 84 9321
25
50
75
100
125
150
175
200
225
=
RL= 50kΩ
∞
RL
5V OUTPUT
INPUT VOLTAGE (VOLTS)
6
0
3
06
1D-23
DROPOUT
CHARACTERISTICS
3
OUTPUT VOLTAGE (VOLTS)
12 45
1
2
4
5
RL= 50kΩ
RL= 50Ω
5V OUTPUT
TYPICAL PERFO RM ANCE CHARACTERI STIC S
INPUT VOLTAGE (VOLTS)
120
0010
1D-25
INPUT CURRENT
INPUT CURRENT (mA)
5 6 7 84 9321
60
20
40
80
100
10
70
30
50
90
110 RL= 50Ω
5V OUTPUT
INPUT VOLTAGE (VOLTS)
160
008
1D-27
QUIESCENT CURRENT
QUIESCENT CURRENT (µA)
1 2 3 4 5 6 7
20
40
60
100
120
140
80
5V OUTPUT
IL= 1mA
IL= 0
TEMPERATURE (˚C)
5.06
4.94
5.0
–75 150
1D-26
OUTPUT VOLTAGE vs
TEMPERATURE OF 3
REPRESENTATIVE UNITS
OUTPUT VOLTAGE (V)
4.96
4.98
5.02
5.04
–50 –25 0 25 50 75 100 125
5V OUTPUT
0.2%
TEMPERATURE (˚C)
170
100
–75 150
1D-28
SHORT CIRCUIT CURRENT
SHORT CIRCUIT CURRENT (mA)
–50 –25 0 25 50 75 100 125
160
150
140
130
120
110
OUTPUT CURRENT
500
0
100µA 100mA
1D-30
DROPOUT VOLTAGE
DROPOUT VOLTAGE (mV)
400
300
200
100
10mA1mA
TJ= 25˚C
TEMPERATURE (˚C)
600
0
–75 150
1D-29
DROPOUT VOLTAGE
DROPOUT VOLTAGE (mV)
–50 –25 0 25 50 75 100 125
500
400
300
100
50
IL= 100mA
IL= 100µA
TEMPERATURE (˚C)
120
50
–75 150
1D-31
QUIESCENT CURRENT
QUIESCENT CURRENT (µA)
–50 –25 0 25 50 75 100 125
110
100
90
80
70
60
5V OUTPUT
VIN = 6V
IL= 100µA
INPUT VOLTAGE (V)
8
008
1D-33
QUIESCENT CURRENT
QUIESCENT CURRENT (mA)
1 2 3 4 5 6 7
1
2
3
5
6
7
4IL= 100mA
5V OUTPUT
TEMPERATURE (˚C)
10
7
–75 150
1D-32
QUIESCENT CURRENT
QUIESCENT CURRENT (mA)
–50 –25 0 25 50 75 100 125
9
8
5V OUTPUT
VIN = 6V
IL= 100mA
LP2950 / LP2951
CORPORATION
CALOGIC COR PORATION, 237 Whitn ey Place, Fremont, California 9453 9, Telephone: 510 -656- 2900, FAX: 510-65 1-3025
TEMPERATURE (˚C)
2.2
1.6
–75 150
1D-34
LP2951 MINIMUM
OPERATING VOLTAGE
MINIMUM OPERATING VOLTAGE (V)
–50 –25 0 25 50 75 100 125
2.0
1.8
1.7
2.1
1.9
FEEDBACK VOLTAGE (V)
50
–250
–2.0 1.0
1D-36
LP2951 FEEDBACK
PIN CURRENT
FEEDBACK CURRENT (µA)
–100
–150
–200
–1.5 –1.0 0.50–0.5
–50
0
TA= 125˚C
TA= –55˚C
PIN 7 DRIVEN BY
EXTERNAL SOURCE
(REGULATROR RUN
OPEN LOOP)
TA= 25˚C
TEMPERATURE (˚C)
20
–30
–75 150
1D-35
LP2951 FEEDBACK
BIAS CURRENT
BIAS CURRENT (nA)
–50 –25 0 25 50 75 100 125
10
0
–10
–20
INPUT VOLTAGE (V)
8
–2 5
1D-37
LP2951 ERROR
COMPARATOR OUTPUT
COMPARATOR OUTPUT (V)
6
4
2
0
4
3210
VOUT = 5V
NOTE: PULLUP RESISTOR
TO SEPARATE 5V SUPPLY
HYSTERESIS
TIME (µs)
100mV
4V 800
1D-39
LINE TRANSIENT
RESPONSE
INPUT
VOLTAGE
0 200 400 600
0
8V
6V
50mV
–50mV
OUTPUT VOLTAGE
CHANGE
IL= 1mA
VOUT = 5V
CL= 1µA
OUTPUT LOW VOLTAGE (V)
2.5
0.0
0.0 0.9
1D-38
LP2951 COMPARATOR
SINK CURRENT
SINK CURRENT (mA)
0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8
2.0
1.5
1.0
0.5
TA= 125˚C
TA= 25˚C
TA= –55˚C
TYPICAL PERFO RM ANCE CHARACTERI STICS (continued)
FREQUENCY (Hz)
10
0.01
10 1M
OUTPUT IMPEDANCE
OUTPUT IMPEDANCE (OHMS)
100 1K 100K10K
0.1
1
0.02
0.05
0.2
0.5
2
5
1D-40
IO= 100µA
IO= 1mA IO= 100mA
VOUT = 5V
CL= 1µA
FREQUENCY (Hz)
90
20
1D-42
RIPPLE REJECTION
RIPPLE REJECTION (dB)
80
70
60
50
40
30
106
105
104
103
102
101
IL= 1mA
IL= 10mA
VOUT
CL= 1µF
VIN = 6V
= 5V
FREQUENCY (Hz)
90
20
1D-41
RIPPLE REJECTION
RIPPLE REJECTION (dB)
80
70
60
50
40
30
106
105
104
103
102
101
IL= 0
IL= 100µA
VOUT = 5V
VIN = 6V
CL= 1µF
TIME (ms)
250
100µA
5
1D-43
LOAD TRANISENT
RESPONSE
LOAD CURRENT
50
100mA
150
OUTPUT VOLTAGE
CHANGE (mV)
43210
200
100
0
–50
–100 CL= 1µF
VOUT = 5V
TIME (µs) 1D-45
LP2951
ENABLE TRANSIENT
SHUTDOWN
PIN VOLTAGE (V) OUTPUT
VOLTAGE (V)
–100 7000100 200 300 400 500 600
7
–2
0
2
0
1
2
3
4
5
6CL= 1µF
IL= 10mA
VIN = 8V
VOUT = 5VCL= 10µF
TIME (ms)
80
100µA
20
1D-44
LOAD TRANSIENT
RESPONSE
LOAD CURRENT
0
100mA
40
OUTPUT VOLTAGE
CHANGE (mV)
1612840
60
20
–20
–40
–60
OUT
CL= 10µF
V = 5V
LP2950 / LP2951
CORPORATION
CALOGIC COR PORATION, 237 Whitn ey Place, Fremont, California 9453 9, Telephone: 510 -656- 2900, FAX: 510-65 1-3025
TYPICAL APPL ICA TION S
1F-44
*SEE APPLICATION INFO.
OUTPUT
VOLTAGE
INPUT
VOLTAGE
4.75V
ERROR*
1.3V
5.0V
R1
+VIN
LP2951
FB
4
1F-45
SD
GND
VOUT
7
ERROR
8
1
3
R2
ERROR
OUTPUT
SHUTDOWN
INPUT 3.3µF
+
+VIN
1.2 TO 30V
1.23V
.01µF
100K
5
VREF
R
1
+V
IN
LP2951
FB
4
1F-46
SD
GND
V
OUT
7
ERROR
8
1
+V
IN
1µF
+
3
V
OUT
470KΩ
470KΩ
R
2
LATCH OFF WHEN ERROR FLAG OCCURS
5
*V
OUT
= V
IN
+V
IN
LP2951
FB
4
1F-47
SD
GND
V
OUT
7
ERROR
OUTPUT
SHUTDOWN
INPUT
ERROR
8
1
+V
IN
*MINIMUM INPUT - OUTPUT VOLTAGE RANGES FROM 4mV TO 400mV.
DEPENDING ON LOAD CURRENT. CURRENT LIMIT IS TYPICALLY 160mA.
WIDE INPUT VOLTAGE RANGE CURRENT LIMITER
5
3
FIGURE 1. ERROR OU TPUT TIM ING FIGURE 2. ADJUSTABLE REGU LATOR
CALOGIC COR PORATION, 237 Whitn ey Place, Fremont, California 9453 9, Telephone: 510 -656- 2900, FAX: 510-65 1-3025
LP2950 / LP2951
CORPORATION
TYPICAL APPLI CA T IONS (continued)
LP2951
4
1G-24
GND
8
1
3
SENSE
MAIN V-
MEMORY V+
NI-CAD
BACKUP
BATTERY
CLM385
6V
SEALED
LEAD-
ACID
BATTERY
SOURCE
100KΩ
1.5KΩ120KΩ
400KΩ
20KΩ
FB IN457
SD
V
OUT
+V
IN
FOR 5.5V
LOW BATTERY DISCONNECT
+
1µF
+
+V
IN
LP2951
TAP
4
1G-25
SD
GND
V
OUT
6
ERROR
8
1
1
µ
F
+
3
+V
OUT
39k
Ω
100k
Ω
100k
Ω
100k
Ω
–
+
C4
2
SENSE
= 5V
7
39k
Ω
100k
Ω
1k
Ω
1k
Ω
10k
Ω
20k
Ω
<6.2V**
<6.0V**
<5.8V**
1%
1%
1%
1%
5
R
3
6V
LEAD-
ACID
BATTERY
REGULATOR WITH STATE-OF-CHARGE INDICATOR
RESET
–
+
C1
–
+
C2
–
+
C3
*OPT IONAL LATCH OFF WHEN DRO POUT OCCURS. ADJUST R3 FOR C2 SWI TCHING WHEN V IS 6.0V.
**OUTPUTS GO LOW WHEN V DROPS BELOW DESIGNATED THRESHHOLDS.
IN
IN
CALOGIC COR PORATION, 237 Whitn ey Place, Fremont, California 9453 9, Telephone: 510 -656- 2900, FAX: 510-65 1-3025
LP2950 / LP2951
CORPORATION
TYPICAL APPLI CA T IONS (continued)
+V
IN
LP2951
FB
4
1F-48
GND
8
5
SYSTEM OVER TEMPERATURE PROTECTION CIRCUIT
AUX SHUTDOWN
INPUT
+V
IN
AS35
5 DEGREE SHUTDOWN FLAG
V
OUT
1
EXTERNAL CIRCUIT
PROTECTED FROM
OVER TEMPERATURE
(V+ GOES OFF WHEN
TEMP > 125)
OR
TEMP
SENSOR
7
+
–
3ERROR
SD
10KΩ
ON OFF
RELAY
8.2KΩ
LP2951
4
1F-49
GND
8
1
OPEN CIRCUIT DETECTOR FOR 4mA TO 20mA CURRENT LOOP
7
FB 2
4 20mA
IN4001
360KΩ
0.1µF
IN457
OUTPUT
4.7mA
+5v
MIN VOLTAGE = 4V
+V
IN
V
OUT
LP2951
4.7µFLOAD 50mA
TO 300mA
OUTPUT
5V
1
2
SENSE
GND
5
UNREGULATED INPUT
3
300mA REGULATOR WITH 0.75 DROPOUT
74
2N5432
27KΩ
330KΩ
IN
1F-50
V
TAP
FB
V
OUT
+
CALOGIC COR PORATION, 237 Whitn ey Place, Fremont, California 9453 9, Telephone: 510 -656- 2900, FAX: 510-65 1-3025
LP2950 / LP2951
CORPORATION
SCHEMATIC DIAGRAM
GND
SHDN
5V TAP
SENSE
OUT
FEEDBACKIN
R25
2.8
k
Ω
R23 60k
Ω
R21 8
Ω
R24
50k
Ω
R16
30k
Ω
R15
100k
Ω
R17
10
Ω
R13
100
k
Ω
R14
350
k
Ω
R22
150k
Ω
R17
12k
Ω
R28
60k
Ω
R27
182k
Ω
R18
20k
Ω
R26
60k
Ω
R3
50k
Ω
R4
13k
Ω
R30
30k
Ω
R5
180
k
Ω
R6
140
k
Ω
R9
27.8k
Ω
R2
50k
Ω
R1
20k
Ω
R8
31.4k
Ω
R10
150
k
Ω
R12
110
k
Ω
R11
18
k
Ω
R11
20.6
k
Ω
Q1
Q30 Q31
Q19Q18 Q29
Q28
Q22
Q21
Q20
Q34
Q40 Q41
Q42
Q13 Q12
Q3 Q4 Q7
Q8
Q9
Q6
Q15A Q15B
Q16 Q17
Q14
Q25
Q24
Q23
Q11
Q38
Q37 Q36
Q39
Q26
Q2
Q5
C1
20pF
C2
40pF
1G-01
10
4
2
5
6
3
4
1
212
3
3
24
ERROR
— — — DENOTES CONNECTION ON L P2950 ONLY
