Datasheet LP2951CS-3, LP2951CP-5, LP2951CP-3.3, LP2951CS-5, LP2951CS-3.3 Datasheet (Calogic LLC)

100mA Low Dropout

Voltage Regulators

LP2950 / LP2951

FEATURES

••

5V, 3.3V, and 3.0V Vers io ns at 100mA Output

••

Ver y Low Q ui e s cent Current

••

Low Dropout Voltage

••

Extremely Tig h t Load and Line Regul ati on

••

Ver y Low Tempe ratur e Coef fi ci ent

••

Current and Thermal Limiting

••

Needs Only 1µF for Stabi lit y

LP2951 Versions Only

••

Error Flag Warns of Output Dropout

••

Logic-Controlled Electronic Shutdown

••

Outpu t Progr am ma bl e from 1. 24 to 2 9V

APPLICATIONS

••

Battery Pow er ed Syst em s

••

Cordless Telephones

••

Radio Control Systems

••

Portable / Palm T op / Noteboo k Comput ers

••

Portable Consumer Equipment

••

Portable I nst ru me nt atio n

••

Avionics

••

SMPS Post-Regula tor

••

V ol tage Ref er en c e

••

Automot i ve El ect r oni cs

PRODUCT DESCRIPTION

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
dropout 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 line regula tion 0.05% typ. and very low output
temperature coefficient, making the LP2950/LP2951 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 falling voltage input of
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 plastic and SO- 8.

The regulator output voltage may be pin-strapped for 5V, 3V
or 3.3 volts or programmed from 1.24 volt to 29 volts with an
external pair of resistors. Use of AS’s design, processing and
testing techniques make our LP2950 and LP2951 superior
over similar product s.

ORDERING INFORMATION
P ART PACKAGE TEMPERATURE RANG E

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 CONNECTIONS

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 CORPORATION, 237 Whitney Place, Fremont, California 9453 9, Telephone: [phone], FAX: [phone]

ABSOLUTE MAXIMUM RATINGS

Power Dissipation . . . . . . . . . . . . . . . . . . . . . Internally Limited

Lead Temp. (Soldering, 5 Seconds) . . . . . . . . . . . . . . . 260

o

C

Storage Tem per atur e Ra nge. . . . . . . . . . . . . . . -65 to +150

o

C
Operating Junct ion Te mper at ure Ra nge

LP2951. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -55 to +150

o

C
LP2950AC/LP2950C

LP2951AC/LP2951C. . . . . . . . . . . . . . . . . . . -40 to +125

o

C

Input Supply Vo ltag e . . . . . . . . . . . . . . . . . . . . . . -0.3 to +30V

Feedback Input Voltage. . . . . . . . . . . . . . . . . . . . -1.5 to +30V

Shutdown Input Voltage. . . . . . . . . . . . . . . . . . . . -0.3 to +30V

Error Comparator Output. . . . . . . . . . . . . . . . . . . -0.3 to +30V

ESD Rating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2KV Min

LP2950 / LP2951

CORPORATION

CALOGIC CORPORATION, 237 Whitney Place, Fremont, California 9453 9, Telephone: [phone], FAX: [phone]

ELECTRICAL CHARACTERISTICS: V

S

= 15V, TA = 25oC, unless otherwise specified .

PARAMETER

LP2951 LP2950AC / LP2951AC 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

-25

o

C ≤ TJ ≤ 85oC

Full Operating T emperature

Output Voltage 2.955 3.0 3.045 2.958 3.0 3.042 2.928 3.0 3.072 V

100µA ≤ I

L

≤ 100mA

T

J

≤T

JMAX

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

T

J

= 25oC

-25

o

C ≤ TJ ≤ 85oC

Full Operating T emperature

Output Voltage 3.251 3.3 3.350 3.254 3.3 3.346 3.221 3.3 3.379 V

100µA ≤ I

L

≤ 100m A

T

J

≤T

JMAX

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

T

J

= 25oC

-25

o

C ≤ TJ ≤ 85oC

Full Operating T emperature

Output Voltage 4.925 5.0 5.075 4.93 5.0 5.07 4.88 5.0 5.12 V

100µA ≤ I

L

≤ 100m A

T

J

≤ T

JMAX

ALL VOLTAGE OPTIONS

Output Voltage
T emperature Coefficient

20 120 20 50 ppm/

o

C (Note 1)

Line Regulation (Note 3) 0.03 0.1 0.03 0.1 0.04 0.2 % 6V ≤ V

IN

≤ 30V (Note 4)

Load Regulation (Note 3) 0.04 0.1 0.04 0.1 0.1 0.2 % 100µA ≤ I

L

≤ 100m A

Dropout Voltage
(Note 5)

50

38080450

50

38080450

50

38080450mVmV

I

L

= 100µA

I

L

= 100m A

Ground Current

1508170

12

1508170

12

1508170

12

µAmAI

L

= 100µA

I

L

= 100m A

Current Limit 130 200 130 200 130 200 mA V

OUT

= 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

C

L

= 1µF

C

L

= 200µF

C

L

= 13.3µF

(Bypass = 0.01µF pins 7 to 1 (LP2951))

8-PIN VERSIONS ONLY LP2951 LP2951AC LP2951C

Reference Voltage 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 Voltage

T emperature Coefficient

20 20 50 ppm/

o

C (Note 7)

Feedback Pin Bias Current
T emperature Coefficient

0.1 0.1 0.1 nA/

o

C

LP2950 / LP2951

CORPORATION

BLOCK DIAGRAM

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 CORPORATION, 237 Whitney Place, Fremont, California 9453 9, Telephone: [phone], FAX: [phone]

ELECTRICAL CHARACTERISTIC S (continued)

PARAMETER

LP2951 LP2950AC / LP2951AC 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 V

IN

= 4.5V, IOL = 400µA
Upper Threshold Voltage 40 60 40 60 40 60 mV (Note 7)
Lower Threshold Voltage 75 95 75 95 75 95 mV (Note 7)
Hysteresis 15 15 15 mV (Note 7)

SHUTDOWN INPUT

Inp ut Logic Voltage

2

1.3 0.6
2

1.3 0.7
2

1.3 0.7 V
V

Low (Regulato r ON)
High (Regulator OFF)

Shutdown Pin
Input Current

30

67550800

30

67550800

30

67550800

µAµAV

S

= 2.4V

V

S

= 30V

Regulator Output Current
in Shutdown

310 310 310µA (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 T

J

= 25oC, 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 LP2951 is tested at 150

o

C for IL = 1mA. For IL = 100µA and TJ = 125oC, line regulatio n is guara nte ed by desig 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 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 input account.

Note 6: V

REF

≤ V

OUT

≤ (VIN - 1V), 2.3 ≤ VIN ≤ 30V, 100µA ≤ IL ≤ 100mA, TJ ≤ 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 thre sh old s in terms of output vo lta ge chan ge , mu ltip l y by the erro r amp lifi er g ai n = 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 = 384mV. Thresho lds 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: All typical values are not guaranteed.

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 are acceptable. For operations
below -25

o

C a solid tantalum is recommended since the

many aluminum types have electrolytes that freeze at about

-30

o

C. The ESR of about 5Ω or less and resonant
frequency about 500kHz are the most imp orta nt param eter s
in the value of the capacitor. The capacitors value may be
increased without limit .

• At lower values of output current, less output cap acitance is

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 output.

• The LP2950, 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 l ike CMOS RAM keep-alive ci rcuits. When
setting the output voltage of the LP2951 version with
external resistors, a m inimum load of 1µA is r ecommended.

• I f 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.

• 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 increasing the ou tput capacitor t o at least 3.3 µF.

ERROR DETECTION COMP A RATOR OUTPUT

The Comparator produces a logic low output whenever the
LP2951 output falls out of regulatio 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
input (in put v oltage at which V

OUT

= 4.75). Sinc 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 point (appro x. 4.75V) does no t vary with load.

The error comparator has an open-collector output which
requires an external pullup resistor. Depending on the syst em
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 LP2951

The LP2951 may be pin-strapped for 5V using its internal
voltage divider by tying Pin 1 (outpu t) to Pin 2 (sense) 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
resistors is requir ed.

Refer to the equation below for the programm ing of the out put
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 recomme nded load current of
1µA forces an upper limit of 1.2MΩ on value of R

2

. If no load

is presented the I

FB

produces an error of typically 2% in V

OUT

which may be eliminate d at room te mperature by trim m ing 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 12µA. Since the LP2951 typically draws
60µA at no l oad 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 lead 3 of LP2950, but is
relatively inefficient, as increasing the capacitor from 1µF to
220µF 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.
C

BYPASS

≅ 1/2πR1 × 200Hz

or choose 0.01µF. When doing this, the output 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
improveme nt s are mor e dram at ic at hig her voltages .

LP2950 / LP2951

CORPORATION

CALOGIC CORPORATION, 237 Whitney Place, Fremont, California 9453 9, Telephone: [phone], FAX: [phone]

LP2950 / LP2951

CORPORATION

CALOGIC CORPORATION, 237 Whitney Place, Fremont, California 9453 9, Telephone: [phone], FAX: [phone]

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

0

010

1D-24

INPUT CURRENT

INPUT CURRENT (µA)

5 6 7 84 9321

25

50

75

100

125

150

175

200

225

=

RL= 50kΩ

∞

R

L

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

R

L

= 50Ω

5V OUTPUT

TYPICAL PERFORMANCE CHARACTERI STIC S

INPUT VOLTAGE (VOLTS)

120

0

010

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

0

08

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

I

L

= 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

I

L

= 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

V

IN

= 6V

I

L

= 100µA

INPUT VOLTAGE (V)

8

0

08

1D-33

QUIESCENT CURRENT

QUIESCENT CURRENT (mA)

1 2 3 4 5 6 7

1

2

3

5

6

7

4

IL= 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
I

L

= 100mA

LP2950 / LP2951

CORPORATION

CALOGIC CORPORATION, 237 Whitney Place, Fremont, California 9453 9, Telephone: [phone], FAX: [phone]

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

T

A

= –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

V

OUT

= 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
V

OUT

= 5V

C

L

= 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

T

A

= 25˚C

T

A

= –55˚C

TYPICAL PERFORMANCE CHARACTERI STICS ( cont inue d)

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

I

O

= 1mA IO= 100mA

V

OUT

= 5V

C

L

= 1µA

FREQUENCY (Hz)

90

20

1D-42

RIPPLE REJECTION

RIPPLE REJECTION (dB)

80

70

60

50

40

30

10

6

10

5

10

4

10

3

10

2

10

1

IL= 1mA

IL= 10mA

V

OUT

CL= 1µF
V

IN

= 6V

= 5V

FREQUENCY (Hz)

90

20

1D-41

RIPPLE REJECTION

RIPPLE REJECTION (dB)

80

70

60

50

40

30

10

6

10

5

10

4

10

3

10

2

10

1

IL= 0

I

L

= 100µA

V

OUT

= 5V

V

IN

= 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

V

OUT

= 5V

TIME (µs)

1D-45

LP2951

ENABLE TRANSIENT

SHUTDOWN

PIN VOLTAGE (V)

OUTPUT

VOLTAGE (V)

–100 7000 100 200 300 400 500 600

7

–2

0

2

0

1

2

3

4

5

6

CL= 1µF

I

L

= 10mA

V

IN

= 8V

V

OUT

= 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 CORPORATION, 237 Whitney Place, Fremont, California 9453 9, Telephone: [phone], FAX: [phone]

TYPICAL APPLICA TION S

1F-44

*SEE APPLICATION INFO.

OUTPUT
VOLTAGE

INPUT
VOLTAGE

4.75V

ERROR*

1.3V

5.0V

R

1

+V

IN

LP2951

FB

4

1F-45

SD

GND

V

OUT

7

ERROR

8

1

3

R

2

ERROR
OUTPUT

SHUTDOWN
INPUT

3.3µF

+

+V

IN

1.2 TO 30V

1.23V

.01µF

100K

5

V

REF

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 OUTPUT TIMING FIGURE 2. ADJUSTABLE REG ULATOR

CALOGIC CORPORATION, 237 Whitney Place, Fremont, California 9453 9, Telephone: [phone], FAX: [phone]

LP2950 / LP2951

CORPORATION

TYPICAL APPLICA T IONS (continue d)

LP2951

4

1G-24

GND

8

1

3

SENSE

MAIN V-

MEMORY V+

NI-CAD
BACKUP
BATTERY

CLM385

6V
SEALED
LEAD­ACID
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

1µF

+

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
LEAD­ACID
BATTERY

REGULATOR WITH STATE-OF-CHARGE INDICATOR

RESET

–
+

C1

–

+

C2

–

+

C3

*OPTIONAL LATCH OFF WHEN DROPOUT OCCURS. ADJUST R3 FOR C2 SWITCHING WHEN V IS 6.0V.

**OUTPUTS GO LOW WHEN V DROPS BELOW DESIGNATED THRESHHOLDS.

IN

IN

CALOGIC CORPORATION, 237 Whitney Place, Fremont, California 9453 9, Telephone: [phone], FAX: [phone]

LP2950 / LP2951

CORPORATION

TYPICAL APPLICA T IONS (continue d)

+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

+

–

3

ERROR

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

4.7µF
LOAD 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 CORPORATION, 237 Whitney Place, Fremont, California 9453 9, Telephone: [phone], FAX: [phone]

LP2950 / LP2951

CORPORATION

SCHEMAT IC 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

2

1

2

3

3

24

ERROR

— — — DENOTES CONNECTION ON LP2950 ONLY