calogic LP2950, LP2951 User Manual

查询LP2950AC供应商

CORPORATION

100mA Low Dropout

Voltage Regulators

LP2950 / LP2951

FEATURES

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

••

Ver y Low Quiescent Cur rent

••

Low Dropout Voltage

••

Extremely Ti gh t Load and Line Regul ati on

••

Ver y Low Tempe ratur e Coef f ici 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 t o 29V

••

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 als o availabl 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

PIN CONNECTIONS

8-PIN SURFACE MOUNT

INPUT

OUTPUT

SENSE

SHUTDOWN

GROUND

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

1
2

LP2951

3
4 5 ERROR

TOP VIEW

8

FEEDBACK

7

5V OR 3.3V TAP

6

1D-19

TO-92

123

BOTTOM VIEW

1. OUTPUT

2. GROUND

3. INPUT

1D-20

LP2950 / LP2951

ABSOLUTE MAXIMUM RATINGS

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

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

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

Operating Ju nction Te mper at ure Ra n ge

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

LP2950AC/LP2950C

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

o
o

o

o

CORPORATION

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

C
C

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

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

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

C

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

C

ELECTRICAL CHARACTERISTICS: V

PARAMETER

LP2951 LP2950AC / LP2951AC LP2950C / LP2951C

MIN TYP MAX MIN TYP MAX MIN TYP MAX

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

S

UNITS

CONDITIONS

(Note 2)

3V VERSIONS

Output Voltage

2.985

2.964

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

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

TJ = 25oC
V
V

o

-25

C ≤ TJ ≤ 85oC

Full Operating T emperature

100µA ≤ I

T

J

≤T

L

JMAX

≤ 100mA

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

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

V
V
V

= 25oC

T

J

o

-25

C ≤ TJ ≤ 85oC

Full Operating T emperature

100µA ≤ I

T

J

≤T

JMAX

≤ 100m A

L

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

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

V
V
V

= 25oC

T

J

o

-25

C ≤ TJ ≤ 85oC

Full Operating T emperature

100µA ≤ I

T

J

≤ T

JMAX

≤ 100m A

L

ALL VOLTAGE OPTIONS

Output Voltage
T emperature Coefficient

20 120 20 50 ppm/

Line Regulation (Note 3) 0.03 0.1 0.03 0.1 0.04 0.2 % 6V ≤ V
Load Regulation (Note 3) 0.04 0.1 0.04 0.1 0.1 0.2 % 100µA ≤ I
Dropout Voltage

(Note 5)
Ground Current

50

38080450
1508170

12

50

38080450
1508170

12

50

38080450
1508170

12

Current Limit 130 200 130 200 130 200 mA V

o

C (Note 1)

mVmVI

µAmAI

= 100µA

L

I

= 100mA

L

= 100µA

L

I

= 100mA

L

= 0

OUT

≤ 30V (Note 4)

IN

≤ 100m A

L

Thermal Regulation 0.05 0.2 0.05 0.2 0.05 0.2 %/W

C

Output Noise,
10Hz to 100KHz

430
160
100

430
160
100

430
160
100

µVrms
µVrms
µVrms

= 1µF

L

C

= 200µF

L

C

= 13.3µF

L

(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
Feedback Pin Bias Current

T emperature Coefficient

20 20 50 ppm/

0.1 0.1 0.1 nA/

o

C (Note 7)

o

C

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

LP2950 / LP2951

CORPORATION

ELECTRICAL CHARACTERISTIC S (continued)

PARAMETER

LP2951 LP2950AC / LP2951AC LP2950C / LP2951C

MIN TYP MAX MIN TYP MAX MIN TYP MAX

UNITS

ERROR COMPARATOR

Output Leakage Current 0.01 1 0.01 1 0.01 1 µAV
Output Low Voltage 150 250 150 250 150 250 mV V
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

Input Logic Voltage
Shutdown Pin

Input Current
Regulator Output Current

in Shutdown

1.3 0.6

2

30

67550800

310 310 310µA (Note 9)

2

1.3 0.7

30

67550800

1.3 0.7 V

2

30

67550800

V

µAµAV

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

versions are feedback tied to 5V tap and output tied to output Sense (V

= 25oC, VIN = 6V, IL=100µA and CL = 1µF. Additional conditions for the 8-pin

J

= 5V) and V

OUT

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.

o

Note 4: Line regulation for the LP2951 is tested at 150

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

≤ (VIN - 1V), 2.3 ≤ VIN ≤ 30V, 100µA ≤ IL ≤ 100mA, TJ ≤ T

OUT

JMAX

.

≤ V

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 term s of outp ut vo lta ge chan ge , mu ltip l y by the erro r amp lifier gain = V
(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. Thresho lds remain consta nt as a percent of V

OUT

as V

is varied, with the dropout warning occurring at typically 5% below

OUT

nominal, 7.5% guaranteed.
Note 8: V

SHUTDOWN

≥ 2V, VIN ≤ 30V, V

= 0, Feedback pin tied to 5V Tap.

OUT

Note 9: All typical values are not guaranteed.

CONDITIONS

(Note 2)

= 30V

OH

= 4.5V, IOL = 400µA

IN

Low (Regulato r ON)

High (Regulator OFF)

= 2.4V

S

V

= 30V

S

OUT/VREF

=

BLOCK DIAGRAM

UNREGULATED DC

5V @ 100mA
MAX

+

1µF

TO CMOS OR
TTL

330kΩ

1D-21

FROM
CMOS

OR TTL

+

3

SHUTDOWN

60mV

LP2950 AND LP2951 BLOCK DIAGRAM

+

1.23V

+

REFERENCE

817

INPUT OUTPUTFEEDBACK

+
–

ERROR
AMPLIFIER

+

ERROR DETECTION

–

COMPARATOR

180kΩ

60kΩ

2

SENSE

6

5V TAP

5

ERROR

4

GROUND

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

LP2950 / LP2951

APPLICATION HINTS
EXTERNAL CAP ACI T O RS

• 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
many aluminum types have electrolytes that freeze at about

-30
frequency about 500kHz are the m ost 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 capacitance 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 minimum load of 1µA is recommended.

• I f there is more than 10 inches of wire between the input

and the AC fi lter 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 to at least 3.3 µF.

ERROR DETECTION COMPARAT O R 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
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 (app rox. 4.75V) does no t vary with load.

o

C a solid tantalum is recommended since the

o

C. The ESR of about 5Ω or less and resonant

= 4.75). Sinc e the LP2951’s

OUT

CORPORATION

The error comparator has an open-collector output which
requires an external pullup resistor. Depending on 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 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 program ming of the out put
voltage:

V
The V

REF

= V

OUT

is 1.235 and IFB is the feedback bias current,

× (1 + R1\R2) + IFBR

REF

1

nominally -20nA. The minimum recomme nded load curren t of
1µA forces an upper limit of 1.2MΩ on value of R
is presented the I

produces an error of typically 2% in V

FB

. If no load

2

OUT

which may be eliminate d at room te m per at ur e 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

, since it reduces the high frequency gain from 4 to

1

unity.
C

≅ 1/2πR1 × 200Hz

BYPASS

or choose 0.01µF. When doing this, the output capacit or m ust
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 m ore dr amat ic at hig her voltages .

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

CORPORATION

TYPICAL PERFORMANCE CHARACTERI STI CS

QUIESCENT CURRENT

10

1

0.1

GROUND PIN CURRENT (mA)

0.01

0.1 100

120
110
100

90
80
70
60
50
40
30

INPUT CURRENT (mA)

20
10

0

010

1.0 10

LOAD CURRENT (mA)

INPUT CURRENT

5V OUTPUT

INPUT VOLTAGE (VOLTS)

5 6 7 84 9321

1D-22

RL= 50Ω

1D-25

DROPOUT

CHARACTERISTICS

6

5V OUTPUT

5

4

3

2

1

OUTPUT VOLTAGE (VOLTS)

0

5.06

5.04

5.02

5.0

4.98

OUTPUT VOLTAGE (V)

4.96

4.94
–75 150

RL= 50kΩ

R

= 50Ω

L

12 45

06

INPUT VOLTAGE (VOLTS)

OUTPUT VOLTAGE vs

TEMPERATURE OF 3

REPRESENTATIVE UNITS

5V OUTPUT

–50 –25 0 25 50 75 100 125

3

0.2%

TEMPERATURE (˚C)

1D-23

1D-26

250
225
200
175
150
125
100

75

INPUT CURRENT (µA)

50
25

0

160
140
120
100

80
60
40

QUIESCENT CURRENT (µA)

20

0

LP2950 / LP2951

INPUT CURRENT

5V OUTPUT

RL= 50kΩ

=

R

∞

L

010

INPUT VOLTAGE (VOLTS)

QUIESCENT CURRENT

5V OUTPUT

1 2 3 4 5 6 7

08

INPUT VOLTAGE (VOLTS)

5 6 7 84 9321

IL= 1mA

I

= 0

L

1D-24

1D-27

SHORT CIRCUIT CURRENT

170

160

150

140

130

120

110

SHORT CIRCUIT CURRENT (mA)

100

–50 –25 0 25 50 75 100 125

–75 150

TEMPERATURE (˚C)

QUIESCENT CURRENT

120

5V OUTPUT

110

100

90

80

70

QUIESCENT CURRENT (µA)

60

50

–50 –25 0 25 50 75 100 125

–75 150

V

= 6V

IN

I

= 100µA

L

TEMPERATURE (˚C)

1D-28

1D-31

DROPOUT VOLTAGE

600

500

400

300

100

DROPOUT VOLTAGE (mV)

50

0

–50 –25 0 25 50 75 100 125

–75 150

TEMPERATURE (˚C)

QUIESCENT CURRENT

10

5V OUTPUT

9

8

QUIESCENT CURRENT (mA)

7

–50 –25 0 25 50 75 100 125

–75 150

TEMPERATURE (˚C)

IL= 100mA

I

L

VIN= 6V
I

= 100mA

L

= 100µA

1D-29

1D-32

DROPOUT VOLTAGE

500

400

300

200

TJ= 25˚C

100

DROPOUT VOLTAGE (mV)

0

100µA 100mA

8
7
6
5
4
3
2

QUIESCENT CURRENT (mA)

1
0

OUTPUT CURRENT

QUIESCENT CURRENT

5V OUTPUT

1 2 3 4 5 6 7

08

INPUT VOLTAGE (V)

10mA1mA

1D-30

IL= 100mA

1D-33

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

LP2950 / LP2951

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

TYPICAL PERFORMANCE CHARACTERI STI CS ( cont inue d)

CORPORATION

LP2951 MINIMUM

OPERATING VOLTAGE

2.2

2.1

2.0

1.9

1.8

1.7

MINIMUM OPERATING VOLTAGE (V)

1.6
–50 –25 0 25 50 75 100 125

–75 150

TEMPERATURE (˚C)

LP2951 ERROR

COMPARATOR OUTPUT

8

V

= 5V

OUT

6

4

2

0

COMPARATOR OUTPUT (V)

–2

HYSTERESIS

NOTE: PULLUP RESISTOR
TO SEPARATE 5V SUPPLY

INPUT VOLTAGE (V)

3210

LP2951 FEEDBACK

20

10

0

BIAS CURRENT

–50

LP2951 FEEDBACK

50

PIN 7 DRIVEN BY
EXTERNAL SOURCE
(REGULATROR RUN

0

OPEN LOOP)

TA= 125˚C

PIN CURRENT

–100

–10

BIAS CURRENT (nA)

–20

–30

–50 –25 0 25 50 75 100 125

–75 150

1D-34

2.5

2.0

1.5

TEMPERATURE (˚C)

LP2951 COMPARATOR

SINK CURRENT

TA= 125˚C

T

A

1D-35

= 25˚C

1.0
T

= –55˚C

SINK CURRENT (mA)

0.5

4

5

1D-37

0.0

0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8

0.0 0.9
OUTPUT LOW VOLTAGE (V)

A

1D-38

–150

–200

FEEDBACK CURRENT (µA)

–250

–2.0 1.0

100mV

TA= 25˚C

T

= –55˚C

A

–1.5 –1.0 0.50–0.5

FEEDBACK VOLTAGE (V)

LINE TRANSIENT

RESPONSE

50mV

0

CHANGE

–50mV

OUTPUT VOLTAGE

8V

6V

INPUT

VOLTAGE

4V

0 200 400 600

TIME (µs)

= 1µA

C

L

IL= 1mA
V

OUT

1D-36

= 5V

800

1D-39

OUTPUT IMPEDANCE (OHMS)

CHANGE (mV)

OUTPUT VOLTAGE

100mA

100µA

LOAD CURRENT

OUTPUT IMPEDANCE

10

5

IO= 100µA

2

I

= 1mA IO= 100mA

O

1

0.5

0.2

0.1

0.05

V

OUT

C

= 1µA

L

0.02

0.01
100 1K 100K10K

10 1M

250

FREQUENCY (Hz)

LOAD TRANISENT

RESPONSE

200
150
100

50

0

–50

–100

CL= 1µF

V

TIME (ms)

OUT

= 5V

= 5V

43210

RIPPLE REJECTION

90

80

70

IL= 1mA

60

50

40

30

20

2

1

10

10

IL= 10mA

4

3

10

10

FREQUENCY (Hz)

CL= 1µF
V

IN

V

OUT

10

5

= 6V

= 5V

6

10

1D-42

1D-40

RIPPLE REJECTION

90

80

70

60

50

40

CL= 1µF

RIPPLE REJECTION (dB)

30

= 6V

V

IN

V

= 5V

OUT

20

80

2

1

10

10

LOAD TRANSIENT

10

FREQUENCY (Hz)

RESPONSE

IL= 0

I

= 100µA

L

RIPPLE REJECTION (dB)

6

5

4

3

10

10

10

1D-41

60
40
20

0

–20

CHANGE (mV)

OUTPUT VOLTAGE

–40
–60

100mA

CL= 10µF
V = 5V

OUT

100µA

5

1D-43

LOAD CURRENT

TIME (ms)

1612840

20

1D-44

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

CORPORATION

TYPICAL APPLICA TION S

LP2950 / LP2951

ERROR

SD

GND

4

+V

IN

+V

IN

LP2951

8

1

V

OUT

R

1

FB

7

1.23V

REF

R

2

V

4.75V

OUTPUT
VOLTAGE

ERROR*

5.0V

INPUT
VOLTAGE

1.3V

*SEE APPLICATION INFO.

1F-44

ERROR
OUTPUT

SHUTDOWN
INPUT

100K

5

3

FIGURE 1. ERROR OUTPUT TIMING FIGURE 2. ADJUSTABLE REG ULATOR

+V

470KΩ

470KΩ

5

3

ERROR

SD

IN

8

+V

IN

LP2951

GND

4

V

1

V

OUT

FB

OUT

ERROR

5

OUTPUT

+

R

1

1µF

SHUTDOWN

3

INPUT

7

ERROR

SD

GND

4

+V

IN

+V

IN

LP2951

8

1

V

OUT

FB

7

1.2 TO 30V

.01µF

*V

= V

OUT

+

3.3µF

1F-45

IN

R

LATCH OFF WHEN ERROR FLAG OCCURS

2

1F-46

*MINIMUM INPUT - OUTPUT VOLTAGE RANGES FROM 4mV TO 400mV.

DEPENDING ON LOAD CURRENT. CURRENT LIMIT IS TYPICALLY 160mA.

WIDE INPUT VOLTAGE RANGE CURRENT LIMITER

1F-47

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

LP2950 / LP2951

+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

TYPICAL APPLICA T IONS (continue d)

+

6V
SEALED
LEAD­ACID
BATTERY
SOURCE

FOR 5.5V

FB

400KΩ

CLM385

1.5KΩ120KΩ

100KΩ

IN457

CORPORATION

8

+V

IN

LP2951

3

SD

V

OUT

SENSE

1

MAIN V-

MEMORY V+

+

1µF

20KΩ

GND

4

NI-CAD
BACKUP
BATTERY

LOW BATTERY DISCONNECT

1G-24

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

CORPORATION

TYPICAL APPLICA T IONS (continue d)

LP2950 / LP2951

+V

IN

AUX SHUTDOWN
INPUT

3

SD

+V

OFF

ON

LP2951

GND

4

+

TEMP

SENSOR

AS35

–

SYSTEM OVER TEMPERATURE PROTECTION CIRCUIT

4 20mA

8

+V

IN

IN4001

LP2951

0.1µF

GND

4

OPEN CIRCUIT DETECTOR FOR 4mA TO 20mA CURRENT LOOP

1

V

OUT

7

FB 2

IN457

MIN VOLTAGE = 4V

8

IN

4.7mA

ERROR

+5v

360KΩ

V

OUT

FB

7

8.2KΩ

OUTPUT

10KΩ

5

5 DEGREE SHUTDOWN FLAG

1

UNREGULATED INPUT

1F-49

EXTERNAL CIRCUIT

PROTECTED FROM

OVER TEMPERATURE

(V+ GOES OFF WHEN

TEMP > 125)

5

IN

LP2951

3

V

TAP

FB

GND

74

300mA REGULATOR WITH 0.75 DROPOUT

V

OUT

SENSE

1

2

OR

27KΩ

330KΩ

+

4.7µF

RELAY

1F-48

5V
OUTPUT

LOAD 50mA
TO 300mA

2N5432

1F-50

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

LP2950 / LP2951

SCHEMA TIC DIAGRAM

Q3 Q4

R11
18
k

50k

Ω

R5

180

k

R3

Ω

Q42

Q40

30k

R30

Q6

Q1

10

R1

Ω

20k

R2

50k

Ω

Q41

4

Ω

C1

20pF

Ω

Q13 Q12

13k

140

R4

CORPORATION

FEEDBACKIN

R18

Ω

Q28

6

Q22

R15
100k

R16
30k

Q25

20k

3

Ω

Ω

Q26

R17
10

24

Q24

3

OUT

SENSE

R27
182k

Ω

5V TAP

R28

Ω

60k

Q23

3

Ω

Q15A Q15B

Q9

Q7

Q5

R11

20.6
k

Q2

R8

31.4k

27.8k

R9

R6

Ω

k

Q8

Q20

R12

110

k

Ω

Q16 Q17

1

2

R13

100

k

Ω

1

R14
350
k

C2
40pF

Ω

2

Q19Q18

Ω

R10

150

Ω

k

Ω

Ω

Q11

Q14

Q21

R17

12k

Q29

Ω

Ω

ERROR

Q37 Q36

Q38

4

Q39

R26
60k

2

R21 8

Ω

R22

Ω

150k

Q34

Ω

R25

2.8
k

5

Ω

GND

Q30 Q31

— — — DENOTES CONNECTION ON LP2950 ONLY

R24
50k

R23 60k

Ω

SHDN

Ω

1G-01

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