Micrel LP2950, MIC2951 User Manual

LP2950/2951 Micrel

查询LP2950-02BZ供应商

LP2950/2951

100mA Low-Dropout Voltage Regulator

General Description

The LP2950 and LP2951 are micropower voltage regulators
with very low dropout voltage (typically 40mV at light loads
and 380mV at 100mA), and very low quiescent current (75µA
typical). The quiescent current of the LP2950/LP2951
increases only slightly in dropout, thus prolonging battery life.
This feature, among others, makes the LP2950 and LP2951
ideally suited for use in battery-powered systems.

Available in a 3-Pin TO-92 package, the LP2950 is pin­compatible with the older 5V regulators. Additional system
functions, such as programmable output voltage and logic­controlled shutdown, are available in the 8-pin DIP and 8-pin
SOIC versions of the LP2951.

Applications

• Automotive Electronics

• Voltage Reference

• Avionics

Block Diagram and Pin Configurations

UNREGULATED DC

+

INPUTFEEDBACK

Features

• High accuracy 5V, guaranteed 100 mA output

• Extremely low quiescent current

• Low-dropout voltage

• Extremely tight load and line regulation

• Very low temperature coefficient

• Use as regulator or reference

• Needs only 1µF for stability

• Current and thermal limiting

LP2951 Ver sions Only

• Error flag warns of output dropout

• Logic-controlled electronic shutdown

• Output programmable from 1.24 to 29V

5V

150 mA

187

OUTPUT

MAX.

3

FROM
CMOS

OR TTL

321

OUTPUT INPUT

GROUND

TO-92 Plastic Package Bottom View

SHUT­DOWN

(BZ)

3

60 mV

1.23 V
REF.

LP2950 and LP2951 Block Diagram

+
–

ERROR

AMPLIFIER

+

+

ERROR

–

+

(Pin Numbers Refer to LP2951)

DETECTION

COMPARATOR

182

kΩ

60
kΩ

OUTPUT

SENSE

SHUTDOWN

GROUND

2

SENSE

6

5V TAP

ERROR

GROUND

1
2

3
4

DIP and SO Packages

(BN and BM)

+

5

4

1.5 µF

8
7

6
5

330

kΩ

TO CMOS

OR TTL

INPUT

FEEDBACK

5V TAP
ERROR

See MIC2950 for a part with 1) higher output (150 mA), 2) transient protection (60V), and 3) reverse input protection to –20V)

February 1999 3-35

LP2950/2951 Micrel

Additional features available with the LP2951 also include an
error flag output that warns of a low output voltage, which is
often due to failing batteries on the input. This may also be
used as a power-on reset. A logic-compatible shutdown input
is also available which enables the regulator to be switched on
and off. This part may also be pin-strapped for a 5V output,
or programmed from 1.24V to 29V with the use of two external
resistors.

The LP2950 is available as either an -02 or -03 version. The

-02 and -03 versions are guaranteed for junction temperatures

Ordering Information

Part Number Voltage Temperature Range* Package Accuracy

LP2950-02BZ 5.0V –40°C to +125°C 3-Pin TO-92 plastic 0.5%
LP2950-03BZ 5.0V –40°C to +125°C 3-Pin TO-92 plastic 1.0%
LP2951-02BM 5.0V –40°C to +125°C 8-Pin SOIC 0.5%
LP2951-03BM 5.0V –40°C to +125°C 8-Pin SOIC 1.0%
LP2951-02BN 5.0V –40°C to +125°C 8-Pin Plastic DIP 0.5%

from –40°C to +125°C; the -02 version has a tighter output and
reference voltage specification range over temperature. The
LP2951 is available as an -02 or -03 version.

The LP2950 and LP2951 have a tight initial tolerance (0.5%
typical), a very low output voltage temperature coefficient
which allows use as a low-power voltage reference, and
extremely good load and line regulation (0.05% typical). This
greatly reduces the error in the overall circuit, and is the result
of careful design techniques and process control.

LP2951-03BN 5.0V –40°C to +125°C 8-Pin Plastic DIP 1.0%
LP2951-4.8BM 4.85V –40°C to +125°C 8-Pin SOIC 1.0%
* Junction temperatures

Absolute Maximum Ratings

If Military/Aerospace specified devices are required, contact your local
Micrel representative/distributor for availability and specifications.

Power dissipation Internally Limited
Lead Temperature (Soldering, 5 seconds) 260°C
Storage Temperature Range –65°C to +150°C
Operating Junction Temperature Range (Note 8)

LP2950, LP2951 –40°C to +125°C

Input Supply Voltage –0.3V to +30V
Feedback Input Voltage (Notes 9 and 10) –1.5V to +30V
Shutdown Input Voltage (Note 9) –0.3V to +30V
Error Comparator Output Voltage (Note 9) –0.3V to +30V
ESD Rating is to be determined.

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LP2950/2951 Micrel

Electrical Characteristics Note 1 T

= 25°C except as noted.

A

Parameter Condition Min Typ Max Units

Output Voltage LP295x-02 (±0.5%) 4.975 5.000 5.025 V
TJ = 25°C

LP295x-03 (±1%) 4.950 5.000 5.050 V
LP2951-4.8 (±1%) 4.802 4.850 4.899 V

Output Voltage LP295x-02 (±0.5%) 4.950 5.050 V
–25°C ≤ TJ ≤ +85°C

LP295x-03 (±1%) 4.925 5.075 V
LP2951-4.8 (±1%) 4.777 4.872 V

Output Voltage LP295x-02 (±0.5%), –40°C to +125°C 4.940 5.060 V
Over Full Temperature Range

LP295x-03 (±1%), –40°C to +125°C 4.900 5.100 V
LP2951-4.8 (±1%), –40°C to +125°C 4.753 4.947 V

Output Voltage LP295x-02 (±0.5%), 100µA ≤ IL ≤ 100mA, TJ ≤ T
Over Load Variation

LP295x-03 (±1%), 100µA ≤ IL ≤ 100mA, TJ ≤ T
LP2951-4.8 (±1%), 100µA ≤ IL ≤ 100mA, TJ ≤ T

J(max)

J(max)

J(max)

4.930 5.070 V

4.880 5.120 V

4.733 4.967 V

Output Voltage LP295x-02 (±0.5%), Note 12 20 100 ppm/°C
Temperature Coefficient

LP295x-03 (±1%), Note 12 50 150 ppm/°C
LP2951-4.8 (±1%), Note 12 50 150 ppm/°C

Line Regulation LP295x-02 (±0.5%), Notes 14, 15 0.03 0.10 %

0.20 %

LP295x-03 (±1%), Notes 14, 15 0.04 0.20 %

0.40 %

LP2951-4.8 (±1%), Notes 14, 15 0.04 0.20 %

0.40 %

Load Regulation LP295x-02 (±0.5%), Note 14, 100µA ≤ I

≤ 100mA 0.04 0.10 %

L

0.20 %

LP295x-03 (±1%), Note 14, 100µA ≤ I

LP2951-4.8 (±1%), Note 14, 100µA ≤ I

≤ 100mA 0.10 0.20 %

L

≤ 100mA 0.10 0.20 %

L

0.30 %

0.30 %

Dropout Voltage Note 5, I

= 100µA5080mV

L

150 mV

Note 5, I

= 100mA 380 450 mV

L

600 mV

Ground Current I

= 100µA 100 150 µA

L

200 µA

= 100mA 8 12 mA

I

Dropout Current V

L

= 4.5V, IL = 100µA 180 250 µA

IN

14 mA

310 µA

3

February 1999 3-37

LP2950/2951 Micrel

Parameter Condition Min Typ Max Units

Current Limit V

Thermal Regulation Note 13 0.05 0.20 %/W
Output Noise 10Hz to 100kHz, CL = 1µF 430 µV

Reference Voltage LP295x-02 (±0.5%) 1.220 1.235 1.250 V

Reference Voltage LP295x-02 (±0.5%), Note 7 1.190 1.270 V

Feedback Bias Current 20 40 nA

Reference Voltage LP295x-02 (±0.5%), Note 12 20 ppm/°C

Feedback Bias Current 0.1 nA/°C
Temperature Coefficient

Output Leakage Current V

Output Low Voltage (Flag) V

Upper Threshold Voltage Note 6 40 60 mV

Lower Threshold Voltage Note 6 75 95 mV

Hysteresis Note 6 15 mV
Input Logic Voltage LP295x-02 (±0.5%) 1.3 V

= 0V 160 200 mA

OUT

220 mA

RMS

10Hz to 100kHz, CL = 200µF 160 µV
10Hz to 100kHz, CL = 3.3µF, 100 µV

RMS
RMS

0.01µF bypass Feedback to Output

1.200 1.260 V

LP295x-03 (±1%) 1.210 1.235 1.260 V

1.200 1.270 V

LP2951-4.8 (±1%) 1.210 1.235 1.260 V

1.200 1.270 V

LP295x-03 (±1%), Note 7 1.185 1.285 V
LP2951-4.8 (±1%), Note 7 1.185 1.285 V

60 nA

LP295x-03 (±1%), Note 12 50 ppm/°C
LP2951-4.8 (±1%), Note 12 50 ppm/°C

= 30V 0.01 1.00 µA

OH

2.00 µA

= 4.5V, IOL = 200µA 150 250 mV

IN

400 mV

25 mV

140 mV

Low 0.7 V
High 2.0 V

LP295x-03 (±1%) 1.3 V

Low 0.7 V
High 2.0 V

LP2951-4.8 (±1%) 1.3 V

Low 0.7 V
High 2.0 V

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LP2950/2951 Micrel

Parameter Condition Min Typ Max Units

Shutdown Input Current V

SHUTDOWN

V

SHUTDOWN

Regulator Output Current Note 11 3 10 µA
in Shutdown 20 µA

Note 1: Boldface limits apply at temperature extremes.
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

Note 3: Guaranteed and 100% production tested.
Note 4: Guaranteed but not 100% production tested. These limits are not used to calculate outgoing AQL levels.
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

Note 6: Comparator thresholds are expressed in terms of a voltage differential at the Feedback terminal below the nominal reference voltage

Note 7: V
Note 8: The junction-to-ambient thermal resistance of the TO-92 package is 180°C/W with 0.4” leads and 160°C/W with 0.25” leads to a PC board.

Note 9: May exceed input supply voltage.
Note 10: When used in dual-supply systems where the output terminal sees loads returned to a negative supply, the output voltage should be diode-

Note 11:V
Note 12: Output or reference voltage temperature coefficient is defined as the worst case voltage change divided by the total temperature range.
Note 13: Thermal regulation is defined as the change in output voltage at a time T after a change in power dissipation is applied, excluding load or line

Note 14: Regulation is measured at constant junction temperature, using pulse testing with a low duty cycle. Changes in output voltage due to heating

Note 15: Line regulation for the LP2951 is tested at 150°C for IL = 1mA. For IL = 100µA and TJ = 125°C, line regulation is guaranteed by design to

are Feedback tied to 5V Tap and Output tied to Output Sense (V

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.

measured at 6V input. To express these thresholds in terms of output voltage change, multiply by the error amplifier 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/1.235V = 384mV. Thresholds remain constant as a percent of V
typically 5% below nominal, 7.5% guaranteed.

≤ V

REF

The thermal resistance of the 8-pin DIP package is 105°C/W junction-to-ambient when soldered directly to a PC board. Junction-to-ambient
thermal resistance for the SOIC (M) package is 160°C/W.

clamped to ground.

SHUTDOWN

regulation effects. Specifications are for a 50mA load pulse at VIN = 30V (1.25W pulse) for t = 10ms.

effects are covered in the specification for thermal regulation.

0.2%. See Typical Performance Characteristics for line regulation versus temperature and load current.

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

OUT

≥ 2V, VIN ≤ 30 V, V

OUT

= 2.4V 30 50 µA

= 30V 450 600 µA

= 5V) and V

OUT

= 0, with Feedback pin tied to 5V Tap.

JMAX

OUT

as V

.

SHUTDOWN

≤ 0.8V.

is varied, with the dropout warning occurring at

OUT

100 µA

750 µA

/V

REF

=

OUT

3

February 1999 3-39