LP2951CD-5.0 [MOTOROLA]

FIXED/ADJUSTABLE POSITIVE LDO REGULATOR, 0.45V DROPOUT, PDSO8, PLASTIC, SO-8;


型号：	LP2951CD-5.0
厂家：	MOTOROLA
描述：	FIXED/ADJUSTABLE POSITIVE LDO REGULATOR, 0.45V DROPOUT, PDSO8, PLASTIC, SO-8 光电二极管输出元件调节器
文件：	总16页 (文件大小：251K)
中文：	中文翻译
下载：	下载PDF数据表文档文件

Order this document by LP2950/D

MICROPOWER

LOW DROPOUT

VOLTAGE REGULATORS

The LP2950 and LP2951 are micropower voltage regulators that are

specifically designed to maintain proper regulation with an extremely low

input–to–output voltage differential. These devices feature a very low

quiescent bias current of 75 µA and are capable of supplying output currents

in excess of 100 mA. Internal current and thermal limiting protection is

provided.

Z SUFFIX

PLASTIC PACKAGE

CASE 29

The LP2951 has three additional features. The first is the Error Output

that can be used to signal external circuitry of an out of regulation condition,

or as a microprocessor power–on reset. The second feature allows the

output voltage to be preset to 5.0 V, 3.3 V or 3.0 V output (depending on the

version) or programmed from 1.25 V to 29 V. It consists of a pinned out

resistor divider along with direct access to the Error Amplifier feedback input.

The third feature is a Shutdown input that allows a logic level signal to

turn–off or turn–on the regulator output.

(TO–226AA/TO–92)

Pin: 1. Output

2. Ground

3. Input

DT SUFFIX

Due to the low input–to–output voltage differential and bias current

specifications, these devices are ideally suited for battery powered

computer, consumer, and industrial equipment where an extension of

useful battery life is desirable. The LP2950 is available in the three pin case

29 and DPAK packages, and the LP2951 is available in the eight pin

dual–in–line, SO–8 and Micro–8 surface mount packages. The ‘A’ suffix

devices feature an initial output voltage tolerance ±0.5%.

PLASTIC PACKAGE

CASE 369A

(DPAK)

Pin: 1. Input

2. Ground

3. Output

LP2950 and LP2951 Features:

(Top View)

• Low Quiescent Bias Current of 75 µA

• Low Input–to–Output Voltage Differential of 50 mV at 100 µA and

Heatsink surface (shown as terminal 4 in

case outline drawing) is connected to Pin 2.

380 mV at 100 mA

• 5.0 V, 3.3 V or 3.0 V ±0.5% Allows Use as a Regulator or Reference

• Extremely Tight Line and Load Regulation

D SUFFIX

PLASTIC PACKAGE

CASE 751

(SO–8)

• Requires Only a 1.0 µF Output Capacitor for Stability

• Internal Current and Thermal Limiting

LP2951 Additional Features:

N SUFFIX

PLASTIC PACKAGE

• Error Output Signals an Out of Regulation Condition

• Output Programmable from 1.25 V to 29 V

• Logic Level Shutdown Input

CASE 626

DM SUFFIX

PLASTIC PACKAGE

CASE 846A

(Micro–8)

Output

Input

Sense

Shutdown

Gnd

Feedback

Tap

Error Output

(See Following Page for Ordering Information.)

(Top View)

Motorola, Inc. 1996

Rev 4

MOTOROLA ANALOG IC DEVICE DATA

LP2950 LP2951

ORDERING INFORMATION

Operating

Temperature Range

Device

Type

Package

LP2950CZ–**

LP2950ACZ–**

TO–92/TO–226AA

Fixed Voltage

(3.0, 3.3 or 5.0 V)

LP2950CDT–**

LP2950ACDT–**

DPAK

SO–8

LP2951CD

LP2951ACD

Adjustable or

5.0 V Fixed

LP2951CD–**

LP2951ACD–**

Adjustable or Fixed

(3.0, 3.3 V)

T = –40° to +125°C

LP2951CN

LP2951ACN

Adjustable or

5.0 V Fixed

Plastic

LP2951CN–**

LP2951ACN–**

Adjustable or Fixed

(3.0, 3.3 V)

LP2951CDM

LP2951ACDM

Adjustable or

5.0 V Fixed

Micro–8

LP2951CDM–**

LP2951ACDM–**

Adjustable or Fixed

(3.0, 3.3 V)

** = Voltage option of 3.0, 3.3 or 5.0 V.

DEVICE TYPE/NOMINAL OUTPUT VOLTAGE

Device No. (±1%)

Device No. (±0.5%)

Nominal Voltage

LP2950CX–5.0

LP2950CX–3.3

LP2950CX–3.0

LP2951CX

LP2950CX–3.3

LP2951CX–3.0

LP2950ACX–5.0

LP2950ACX–3.3

LP2950ACX–3.0

LP2951ACX

LP2951ACX–3.3

LP2951ACX–3.0

5.0

3.3

3.0

Adjustable or 5.0

Adjustable or 3.3

Adjustable or 3.0

X = Package suffix.

Representative Block Diagrams

Input

Output

5.0 V/100 mA

1.0 µF

Battery or

Unregulated DC

182 k

60 k

Error Amplifier

1.23 V

Reference

LP2950CZ–5.0

Gnd

5.0 V/100 mA

Input

Output

Sense

182 k

Battery or

Unregulated DC

1.0

Tap

60 k

330 k

Feedback

Error

Amplifier

Shutdown

From

60 k

50 k

75 mV/

60 mV

CMOS/TTL

Error

Output

To CMOS/TTL

Error Detection

Comparator

1.23 V

Reference

LP2951CD or CN

Gnd

This device contains 34 active transistors.

MOTOROLA ANALOG IC DEVICE DATA

LP2950 LP2951

MAXIMUM RATINGS (T = 25°C, unless otherwise noted.)

Rating

Symbol

Value

Unit

Input Voltage

Vdc

Power Dissipation and Thermal Characteristics

Maximum Power Dissipation

Internally Limited

Case 751(SO–8) D Suffix

Thermal Resistance, Junction–to–Ambient

Thermal Resistance, Junction–to–Case

Case 369A (DPAK) DT Suffix [Note 1]

Thermal Resistance, Junction–to–Ambient

Thermal Resistance, Junction–to–Case

Case 29 (TO–226AA/TO–92) Z Suffix

Thermal Resistance, Junction–to–Ambient

Thermal Resistance, Junction–to–Case

Case 626 N Suffix

180

°C/W

θJA

θJC

θJA

θJC

6.0

°C/W

θJA

θJC

160

°C/W

Thermal Resistance, Junction–to–Ambient

Case 846A (Micro–8) DM Suffix

105

°C/W

θJA

Thermal Resistance, Junction–to–Ambient

240

°C/W

θJA

Feedback Input Voltage

–1.5 to +30

Vdc

Shutdown Input Voltage

–0.3 to +30

–40 to +125

–65 to +150

Vdc

°C

Error Comparator Output Voltage

Operating Junction Temperature

Storage Temperature Range

err

stg

°C

NOTE: 1. The Junction–to–Ambient Thermal Resistance is determined by PC board copper area

per Figure 26.

2. ESD data available upon request.

ELECTRICAL CHARACTERISTICS (V = V + 1.0 V, I = 100 µA, C = 1.0 µF, T = 25°C [Note 1], unless otherwise

noted.)

Characteristic

Output Voltage, 5.0 V Versions

= 6.0 V, I = 100 µA, T = 25°C

Symbol

Min

Typ

Max

Unit

LP2950C–5.0/LP2951C

LP2950AC–5.0/LP2951AC

4.950

4.975

5.000

5.050

5.025

T = –40 to +125°C

LP2950C–5.0/LP2951C

4.900

4.940

–

5.100

5.060

LP2950AC–5.0/LP2951AC

= 6.0 to 30 V, I = 100 µA to 100 mA, T = –40 to +125°C

O J

LP2950C–5.0/LP2951C

LP2950AC–5.0/LP2951AC

4.880

4.925

–

5.120

5.075

Output Voltage, 3.3 V Versions

= 4.3 V, I = 100 µA, T = 25°C

LP2950C–3.3/LP2951C–3.3

LP2950AC–3.3/LP2951AC–3.3

3.267

3.284

3.300

3.333

3.317

T = –40 to +125°C

LP2950C–3.3/LP2951C–3.3

3.234

3.260

–

3.366

3.340

LP2950AC–3.3/LP2951AC–3.3

= 4.3 to 30 V, I = 100 µA to 100 mA, T = –40 to +125°C

O J

LP2950C–3.3/LP2951C–3.3

LP2950AC–3.3/LP2951AC–3.3

3.221

3.254

–

3.379

3.346

Output Voltage, 3.0 V Versions

= 4.0 V, I = 100 µA, T = 25°C

LP2950C–3.0/LP2951C–3.0

LP2950AC–3.0/LP2951AC–3.0

2.970

2.985

3.000

3.030

3.015

T = –40 to +125°C

LP2950C–3.0/LP2951C–3.0

LP2950AC–3.0/LP2951AC–3.0

2.940

2.964

–

3.060

3.036

= 4.0 to 30 V, I = 100 µA to 100 mA, T = –40 to +125°C

O J

LP2950C–3.0/LP2951C–3.0

LP2950AC–3.0/LP2951AC–3.0

2.928

2.958

–

3.072

3.042

MOTOROLA ANALOG IC DEVICE DATA

LP2950 LP2951

ELECTRICAL CHARACTERISTICS (continued) (V = V + 1.0 V, I = 100 µA, C = 1.0 µF, T = 25°C [Note 1], unless otherwise

noted.)

Characteristic

+1.0 V to 30 V) [Note 2]

Symbol

Min

Typ

Max

Unit

Line Regulation (V = V

Reg

O(nom)

line

LP2950C–XX/LP2951C/LP2951C–XX

LP2950AC–XX/LP2951AC/LP2951AC–XX

–

0.08

0.04

0.20

0.10

Load Regulation (I = 100 µA to 100 mA)

Reg

load

LP2950C–XX/LP2951C/LP2951C–XX

LP2950AC–XX/LP2951AC/LP2951AC–XX

–

0.13

0.05

0.20

0.10

Dropout Voltage

V – V

= 100 µA

= 100 mA

–

350

450

Supply Bias Current

= 100 µA

= 100 mA

–

4.0

120

µA

Dropout Supply Bias Current (V = V

– 0.5 V,

–

110

170

µA

O(nom)

CCdropout

= 100 µA) [Note 2]

Current Limit (V Shorted to Ground)

–

220

300

%/W

Limit

Reg

Thermal Regulation

0.05

0.20

thermal

Output Noise Voltage (10 Hz to 100 kHz) [Note 3]

µVrms

= 1.0 µF

= 100 µF

–

126

–

LP2951A/LP2951AC ONLY

Reference Voltage (T = 25°C)

LP2951C/LP2951C–XX

LP2951AC/LP2951AC–XX

ref

1.210

1.220

1.235

1.260

1.250

Reference Voltage (T = –40 to +125°C)

ref

LP2951C/LP2951C–XX

LP2951AC/LP2951AC–XX

1.200

–

1.270

1.260

Reference Voltage (T = –40 to +125°C)

ref

= 100 µA to 100 mA, V = 23 to 30 V

LP2951C/LP2951C–XX

LP2951AC/LP2951AC–XX

1.185

1.190

–

1.285

1.270

Feedback Pin Bias Current

ERROR COMPARATOR

Output Leakage Current (V

–

= 30 V)

–

0.01

150

1.0

250

–

µA

lkg

Output Low Voltage (V = 4.5 V, I

= 400 µA)

Upper Threshold Voltage (V = 6.0 V)

–

thu

Lower Threshold Voltage (V = 6.0 V)

–

thl

Hysteresis (V = 6.0 V)

–

SHUTDOWN INPUT

Input Logic Voltage

shtdn

Logic “0” (Regulator “On”)

Logic “1” (Regulator “Off”)

2.0

–

0.7

Shutdown Pin Input Current

µA

shtdn

= 2.4 V

= 30 V

–

450

600

Regulator Output Current in Shutdown Mode

(V = 30 V, V = 2.0 V, V = 0, Pin 6 Connected to Pin 7)

off

–

3.0

shtdn

NOTES: 1. Low duty pulse techniques are used during test to maintain junction temperature as close to ambient as possible.

2. V is the part number voltage option.

O(nom)

3. Noise tests on the LP2951 are made with a 0.01 µF capacitor connected across Pins 7 and 1.

MOTOROLA ANALOG IC DEVICE DATA

LP2950 LP2951

DEFINITIONS

Dropout Voltage – The input/output voltage differential at

Output Noise Voltage – The rms ac voltage at the output,

with constant load and no input ripple, measured over a

specified frequency range.

Leakage Current – Current drawn through a bipolar

transistor collector–base junction, under a specified collector

voltage, when the transistor is “off”.

Upper Threshold Voltage – Voltage applied to the

comparator input terminal, below the reference voltage

which is applied to the other comparator input terminal,

which causes the comparator output to change state from a

logic “0” to “1”.

Lower Threshold Voltage – Voltage applied to the

comparator input terminal, below the reference voltage

which is applied to the other comparator input terminal,

which causes the comparator output to change state from a

logic “1” to “0”.

which the regulator output no longer maintains regulation

against further reductions in input voltage. Measured when

the output drops 100 mV below its nominal value (which is

measured at 1.0 V differential), dropout voltage is affected by

junction temperature, load current and minimum input supply

requirements.

Line Regulation – The change in output voltage for a

change in input voltage. The measurement is made under

conditions of low dissipation or by using pulse techniques

such that average chip temperature is not significantly

affected.

Load Regulation – The change in output voltage for a

change in load current at constant chip temperature.

Maximum Power Dissipation – The maximum total

device dissipation for which the regulator will operate within

specifications.

Hysteresis – The difference between Lower Threshold

voltage and Upper Threshold voltage.

Bias Current – Current which is used to operate the

regulator chip and is not delivered to the load.

Figure 1. Quiescent Current

Figure 2. Dropout Characteristics

6.0

LP2951C

5.0

4.0

3.0

2.0

= 25°C

= 50 k

1.0

0.1

= 50

Ω

1.0

0.01

0.1

1.0

100

1.0

2.0

3.0

4.0

5.0

6.0

I , LOAD CURRENT (mA)

, INPUT VOLTAGE (V)

Figure 3. Input Current

Figure 4. Output Voltage versus Temperature

250

5.00

200

150

100

4.99

4.98

4.97

4.96

4.95

0.1 mA Load Current

No Load

LP2951C

5.0

– 50

100

150

, INPUT VOLTAGE (V)

T , AMBIENT TEMPERATURE (°C)

MOTOROLA ANALOG IC DEVICE DATA

LP2950 LP2951

Figure 5. Dropout Voltage versus

Output Current

Figure 6. Dropout Voltage versus Temperature

400

350

550

500

= 25°C

300

250

200

150

100

450

400

350

300

= 50

= 50 k

0.1

1.0

100

– 50

T, TEMPERATURE (°C)

100

150

, OUTPUT CURRENT (mA)

Figure 7. Error Comparator Output

Figure 8. Line Transient Response

5.0

4.0

8.0

7.5

7.0

6.5

6.0

5.5

LP2951C

= 330 k

4.0

3.0

2.0

1.0

2.0

= 25°C

Decreasing

out

Increasing

– 2.0

– 4.0

– 6.0

= 25°C

= 1.0 µF

= 1.0 mA

= 5.0 V

4.70

4.74

4.78

4.82

4.86

4.90

100

200

300

400

500

600

700

800

, INPUT VOLTAGE (V)

t, TIME (µs)

Figure 9. LP2951 Enable Transient

Figure 10. Load Transient Response

7.0

6.0

5.0

4.0

3.0

2.0

1.0

200

150

100

= 1.0 µF

= 5.0 V

400

200

out

= 25°C

out

= 10 µF

= 25°C

= 10 mA

= 8.0 V

– 200

– 400

Load

= 5.0 V

out

Shutdown Input

200

–1.0

– 50

–100

100

300

400

100

150

200

t, TIME (ms)

250

300

350

400

t, TIME (µs)

MOTOROLA ANALOG IC DEVICE DATA

LP2950 LP2951

Figure 11. Ripple Rejection

Figure 12. Output Noise

4.0

3.0

I = 100 mA

= 25°C

= 5.0 V

= 1.0 µF

LP2951C

I = 0.1 mA

2.0

1.0

= 25°C

= 1.0 µF

= 6.0 V

= 100 µF

= 5.0 V

out

1.0

1.0 k

f, FREQUENCY (Hz)

100

1.0 k

f, FREQUENCY (Hz)

100

10 k

100 k

10 k

100 k

Figure 13. Shutdown Threshold Voltage

versus Temperature

Figure 14. Maximum Rated

Output Current

1.8

1.6

100

4.0

= 25°C

2.0

= 75°C

1.4

1.2

Output “Off”

Output “On”

– 2.0

– 4.0

– 6.0

1.0

0.8

LP2951CN

5.0

– 40 – 20

100 120 140 160

V , INPUT VOLTAGE (V)

t, TEMPERATURE (

°C)

MOTOROLA ANALOG IC DEVICE DATA

LP2950 LP2951

APPLICATIONS INFORMATION

Introduction

The LP2950/LP2951 regulators are designed with

internal current limiting and thermal shutdown making them

user–friendly. Typical application circuits for the LP2950 and

LP2951 are shown in Figures 17 through 25.

These regulators are not internally compensated and thus

require a 1.0 µF (or greater) capacitance between the

LP2950/LP2951 output terminal and ground for stability.

Most types of aluminum, tantalum or multilayer ceramic will

perform adequately. Solid tantalums or appropriate

multilayer ceramic capacitors are recommended for

operation below 25°C.

When operated in the shutdown mode, the error

comparator output will go high if it has been pulled up to an

external supply. To avoid this invalid response, the error

comparator output should be pulled up to V

Figure 15).

(see

out

Figure 15. ERROR Output Timing

5.0 V

4.70 V

4.75 V

Output

Voltage

At lower values of output current, less output capacitance

is required for output stability. The capacitor can be reduced

to 0.33 µF for currents less than 10 mA, or 0.1 µF for currents

below 1.0 mA. Using the 8–pin versions at voltages less than

5.0 V operates the error amplifier at lower values of gain, so

that more output capacitance is needed for stability. For the

worst case operating condition of a 100 mA load at 1.23 V

output (Output Pin 1 connected to the feedback Pin 7) a

minimum capacitance of 3.3 µF is recommended.

Pull–Up

to Ext

Not

Valid

Not

Valid

ERROR

Pull–Up

to V

out

4.75 V + V

dropout

4.70 V + V

dropout

The LP2950 will remain stable and in regulation when

operated with no output load. When setting the output voltage

of the LP2951 with external resistors, the resistance values

should be chosen to draw a minimum of 1.0 µA.

A bypass capacitor is recommended across the

LP2950/LP2951 input to ground if more than 4 inches of

wire connects the input to either a battery or power supply

filter capacitor.

Input capacitance at the LP2951 Feedback Pin 7 can

create a pole, causing instability if high value external

resistors are used to set the output voltage. Adding a 100 pF

capacitor between the Output Pin 1 and the Feedback Pin 7

and increasing the output filter capacitor to at least 3.3 µF will

stabilize the feedback loop.

Input

Voltage

1.3 V

Programming the Output Voltage (LP2951)

The LP2951CX may be pin–strapped for 5.0 V using its

internal voltage divider by tying Pin 1 (output) to Pin 2 (sense)

and Pin 7 (feedback) to Pin 6 (5.0 V tap). Alternatively, it may

be programmed for any output voltage between its 1.235

reference voltage and its 30 V maximum rating. An external

pair of resistors is required, as shown in Figure 16.

Figure 16. Adjustable Regulator

Error Detection Comparator

The comparator switches to a positive logic low whenever

the LP2951 output voltage falls more than approximately

5.0% out of regulation. This value is the comparator’s

designed–in offset voltage of 60 mV divided by the 1.235 V

internal reference. As shown in the representative block

diagram. This trip level remains 5.0% below normal

regardless of the value of regulated output voltage. For

example, the error flag trip level is 4.75 V for a normal 5.0 V

regulated output, or 9.50 V for a 10 V output voltage.

Figure 1 is a timing diagram which shows the ERROR

signal and the regulated output voltage as the input voltage to

the LP2951 is ramped up and down. The ERROR signal

becomes valid (low) at about 1.3 V input. It goes high when

100 k

Error

Output

out

Error

out

1.23 to 30 V

SNS

Shutdown

Input

0.01 µF

Gnd

3.3 µF

the input reaches about 5.0 V (V

exceeds about 4.75 V).

out

Since the LP2951’s dropout voltage is dependent upon the

load current (refer to the curve in the Typical Performance

Characteristics), the input voltage trip point will vary with load

current. The output voltage trip point does not vary with load.

The error comparator output is an open collector which

requires an external pull–up resistor. This resistor may be

returned to the output or some other voltage within the

system. The resistance value should be chosen to be

consistent with the 400 µA sink capability of the error

comparator. A value between 100 k and 1.0 MΩ is suggested.

No pull–up resistance is required if this output is unused.

The complete equation for the output voltage is:

(

)

R1 R2

out

ref

where V is the nominal 1.235 V reference voltage and I

ref FB

is the feedback pin bias current, nominally –20 nA. The

minimum recommended load current of 1.0 µA forces an

upper limit of 1.2 MΩ on the value of R2, if the regulator must

work with no load. I

which may be eliminated at room temperature by adjusting

R1. For better accuracy, choosing R2 = 100 k reduces this

will produce a 2% typical error in V

out

MOTOROLA ANALOG IC DEVICE DATA

LP2950 LP2951

error to 0.17% while increasing the resistor program current

to 12 µA. Since the LP2951 typically draws 75 µA at no load

with Pin 2 open circuited, the extra 12 µA of current drawn is

often a worthwhile tradeoff for eliminating the need to set

output voltage in test.

Figure 17. 1.0 A Regulator with 1.2 V Dropout

Unregulated

Input

MTB23P06E

1.0 µF

10 k

0.01 µF

Output Noise

In many applications it is desirable to reduce the noise

present at the output. Reducing the regulator bandwidth by

increasing the size of the output capacitor is the only method

for reducing noise on the 3 lead LP2950. However,

increasing the capacitor from 1.0 µF to 220 µF only

decreases the noise from 430 µV to 160 µVrms for a 100 kHz

bandwidth at the 5.0 V output.

Noise can be reduced fourfold by a bypass capacitor

across R1, since it reduces the high frequency gain from 4 to

unity. Pick

out

5.0 V

0 to 1.0 A

1.0%

Error

Output

Error

out

SNS

LP2951CN

Shutdown

Input

220 µF

Gnd

Bypass

0.002

1.0 M

µF

2 R1 x 200 Hz

or about 0.01 µF. When doing this, the output capacitor

must be increased to 3.3 µF to maintain stability. These

changes reduce the output noise from 430 µV to 126 µVrms

for a 100 kHz bandwidth at 5.0 V output. With bypass

capacitor added, noise no longer scales with output voltage

so that improvements are more dramatic at higher output

voltages.

2.0 k

MOTOROLA ANALOG IC DEVICE DATA

LP2950 LP2951

TYPICAL APPLICATIONS

Figure 18. Lithium Ion Battery Cell Charger

Figure 19. Low Drift Current Sink

+V = 2.0 to 30 V

Unregulated Input

6.0 to 10 Vdc

= 1.23/R

Load

1N4001

330 pF

4.2 V ± 0.025 V

Error

out

0.1 µF

2.0 M

1.0%

SNS

Error

Output

LP2951CN

0.1 µF

Error

out

SNS

806 k

1.0%

Lithium Ion

Rechargeable

Cell

Gnd

2.2

µF

LP2951CN

Shutdown

Input

50 k

Gnd

1.0 µF

Figure 20. Latch Off When Error Flag Occurs

Figure 21. 5.0 V Regulator with 2.5 V Sleep Function

CMOS

Gate

*Sleep

Input

470 k

47 k

Error

out

Error

out

2N3906

out

470 k

out

Error

Output

SNS

LP2951CN

Reset

SNS

200 k

100 k

LP2951CN

Shutdown

Input

3.3 µF

Normally

Closed

Gnd

1.0 µF

100 pF

Gnd

100 k

Error flag occurs when V is too low to

maintain V , or if V

out out

excessive load current.

is reduced by

MOTOROLA ANALOG IC DEVICE DATA

LP2950 LP2951

Figure 22. Regulator with Early Warning and Auxiliary Output

Memory

V+

Error

out

1.0 µF

3.6 V

NiCad

SNS

LP2951CN

Gnd

Early Warning

Reset

27 k

All diodes are 1N4148.

Early Warning flag on low input voltage.

µP

2.7 M

Main output latches off at lower input

voltages.

2N3906

Battery backup on auxiliary output.

330 k

Operation: Regulator #1’s V

programmed one diode drop above 5.0 V.

out

Error

out

Main

Output

Its error flag becomes active when V < 5.7

V. When V drops below 5.3 V, the error

flag of regulator #2 becomes active and via

SNS

LP2951CN

1.0 µF

Q1 latches the main output “off”. When V

again exceeds 5.7 V, regulator #1 is back in

regulation and the early warning signal

rises, unlatching regulator #2 via D3.

Gnd

Figure 23. 2.0 A Low Dropout Regulator

Current Limit

Section

0.05

470

680

2N3906

1000 µF

2N3906

MJE2955

.33 µF

10 k

4.7 M

Error

Flag

Error

out

@ 2.0 A

SNS

out

LP2951CN

220

4.7

Tant

µF

100 µF

Gnd

20 k

.01 µF

0.033 µF

= 1.25V (1.0 + R1/R2)

out

For 5.0 V output, use internal resistors. Wire Pin 6 to 7,

and wire Pin 2 to +V Bus.

out

MOTOROLA ANALOG IC DEVICE DATA

LP2950 LP2951

Figure 24. Open Circuit Detector for

4.0 to 20 mA Current Loop

+5.0 V

4.7 k

Output*

20 mA

Error

out

SNS

LP2951CN

* High for

< 3.5 mA

0.1 µF

1N4001

Gnd

1N457

360

Figure 25. Low Battery Disconnect

31.6 k

6.0 V Lead–Acid

Battery

100 k

2N3906

Main V+

Error

out

MC34164P–5

SNS

Memory V+

LP2951CN

1.0 µF

NiCad Backup

Battery

Gnd

Figure 26. DPAK Thermal Resistance and Maximum

Power Dissipation versus P.C.B. Copper Length

100

2.4

for T = 50

D(max)

Free Air

Mounted

Vertically

2.0

1.6

1.2

0.8

0.4

2.0 oz. Copper

Minimum

Size Pad

5.0

L, LENGTH OF COPPER (mm)

MOTOROLA ANALOG IC DEVICE DATA

LP2950 LP2951

OUTLINE DIMENSIONS

Z SUFFIX

PLASTIC PACKAGE

CASE 29–04

(TO–226AA/TO–92)

ISSUE AD

NOTES:

1. DIMENSIONING AND TOLERANCING PER ANSI

Y14.5M, 1982.

2. CONTROLLING DIMENSION: INCH.

3. CONTOUR OF PACKAGE BEYOND DIMENSION R

IS UNCONTROLLED.

4. DIMENSION F APPLIES BETWEEN P AND L.

DIMENSION D AND J APPLY BETWEEN L AND K

MINIMUM. LEAD DIMENSION IS UNCONTROLLED

IN P AND BEYOND DIMENSION K MINIMUM.

SEATING

PLANE

INCHES

MIN

MILLIMETERS

DIM

MAX

0.205

0.210

0.165

0.022

0.019

0.055

0.105

0.020

–––

MIN

4.45

4.32

3.18

0.41

1.15

2.42

0.39

12.70

6.35

2.04

–––

MAX

5.20

5.33

4.19

0.55

0.48

1.39

2.66

0.50

–––

0.175

0.170

0.125

0.016

0.045

0.095

0.015

0.500

0.250

0.080

–––

X X

–––

SECTION X–X

0.105

0.100

–––

2.66

2.54

–––

0.115

0.135

2.93

3.43

–––

DT SUFFIX

PLASTIC PACKAGE

CASE 369A–13

(DPAK)

ISSUE Y

NOTES:

1. DIMENSIONING AND TOLERANCING PER ANSI

Y14.5M, 1982.

SEATING

PLANE

–T–

2. CONTROLLING DIMENSION: INCH.

INCHES

MILLIMETERS

DIM

MIN

MAX

0.250

0.265

0.094

0.035

0.040

0.047

MIN

5.97

6.35

2.19

0.69

0.84

0.94

MAX

6.35

6.73

2.38

0.88

1.01

1.19

0.235

0.250

0.086

0.027

0.033

0.037

0.180 BSC

4.58 BSC

0.034

0.018

0.102

0.040

0.023

0.114

0.87

0.46

2.60

1.01

0.58

2.89

0.090 BSC

2.29 BSC

0.175

0.020

0.030

0.138

0.215

0.050

–––

0.050

–––

4.45

0.51

0.77

3.51

5.46

1.27

–––

1.27

–––

D 2 PL

0.13 (0.005)

MOTOROLA ANALOG IC DEVICE DATA

LP2950 LP2951

OUTLINE DIMENSIONS

N SUFFIX

PLASTIC PACKAGE

CASE 626–05

ISSUE K

NOTES:

1. DIMENSION L TO CENTER OF LEAD WHEN

FORMED PARALLEL.

2. PACKAGE CONTOUR OPTIONAL (ROUND OR

SQUARE CORNERS).

3. DIMENSIONING AND TOLERANCING PER ANSI

Y14.5M, 1982.

–B–

MILLIMETERS

INCHES

DIM

MIN

9.40

6.10

3.94

0.38

1.02

MAX

10.16

6.60

4.45

0.51

1.78

MIN

MAX

0.370

0.240

0.155

0.015

0.040

0.400

0.260

0.175

0.020

0.070

NOTE 2

–A–

2.54 BSC

0.100 BSC

1.27

0.30

3.43

0.030

0.008

0.115

0.050

0.012

0.135

0.76

0.20

2.92

7.62 BSC

0.300 BSC

–

0.76

1.01

0.040

0.030

–T–

SEATING

PLANE

0.13 (0.005)

D SUFFIX

PLASTIC PACKAGE

CASE 751–05

(SO–8)

ISSUE R

NOTES:

1. DIMENSIONING AND TOLERANCING PER ASME

Y14.5M, 1994.

2. DIMENSIONS ARE IN MILLIMETERS.

3. DIMENSION D AND E DO NOT INCLUDE MOLD

PROTRUSION.

4. MAXIMUM MOLD PROTRUSION 0.15 PER SIDE.

5. DIMENSION B DOES NOT INCLUDE MOLD

PROTRUSION. ALLOWABLE DAMBAR

PROTRUSION SHALL BE 0.127 TOTAL IN EXCESS

OF THE B DIMENSION AT MAXIMUM MATERIAL

CONDITION.

0.25

h X 45

MILLIMETERS

DIM

MIN

1.35

0.10

0.35

0.18

4.80

3.80

MAX

1.75

0.25

0.49

0.25

5.00

4.00

SEATING

PLANE

1.27 BSC

0.10

5.80

0.25

0.40

6.20

0.50

1.25

0.25

MOTOROLA ANALOG IC DEVICE DATA

LP2950 LP2951

OUTLINE DIMENSIONS

DM SUFFIX

PLASTIC PACKAGE

CASE 846A–02

(Micro–8)

ISSUE C

NOTES:

1. DIMENSIONING AND TOLERANCING PER ANSI

Y14.5M, 1982.

–A–

2. CONTROLLING DIMENSION: MILLIMETER.

3. DIMENSION A DOES NOT INCLUDE MOLD FLASH,

PROTRUSIONS OR GATE BURRS. MOLD FLASH,

PROTRUSIONS OR GATE BURRS SHALL NOT

EXCEED 0.15 (0.006) PER SIDE.

4. DIMENSION B DOES NOT INCLUDE INTERLEAD

FLASH OR PROTRUSION. INTERLEAD FLASH OR

PROTRUSION SHALL NOT EXCEED 0.25 (0.010)

PER SIDE.

–B–

MILLIMETERS

INCHES

PIN 1 ID

DIM

MIN

2.90

–––

MAX

3.10

1.10

0.40

MIN

MAX

0.122

0.043

0.016

D 8 PL

0.114

–––

0.08 (0.003)

0.25

0.010

0.65 BSC

0.026 BSC

0.05

0.13

4.75

0.40

0.15

0.23

5.05

0.70

0.002

0.005

0.187

0.016

0.006

0.009

0.199

0.028

SEATING

PLANE

–T–

0.038 (0.0015)

MOTOROLA ANALOG IC DEVICE DATA

LP2950 LP2951

Motorola reserves the right to make changes without further notice to any products herein. Motorola makes no warranty, representation or guarantee regarding

the suitability of its products for any particular purpose, nor does Motorola assume any liability arising out of the application or use of any product or circuit, and

specificallydisclaims any and all liability, including without limitation consequential or incidental damages. “Typical” parameters which may be provided in Motorola

datasheetsand/orspecificationscananddovaryindifferentapplicationsandactualperformancemayvaryovertime. Alloperatingparameters,including“Typicals”

must be validated for each customer application by customer’s technical experts. Motorola does not convey any license under its patent rights nor the rights of

others. Motorola products are not designed, intended, or authorized for use as components in systems intended for surgical implant into the body, or other

applicationsintended to support or sustain life, or for any other application in which the failure of the Motorola product could create a situation where personal injury

ordeathmayoccur. ShouldBuyerpurchaseoruseMotorolaproductsforanysuchunintendedorunauthorizedapplication,BuyershallindemnifyandholdMotorola

and its officers, employees, subsidiaries, affiliates, and distributors harmless against all claims, costs, damages, and expenses, and reasonable attorney fees

arising out of, directly or indirectly, any claim of personal injury or death associated with such unintended or unauthorized use, even if such claim alleges that

Motorola was negligent regarding the design or manufacture of the part. Motorola and

Opportunity/Affirmative Action Employer.

are registered trademarks of Motorola, Inc. Motorola, Inc. is an Equal

How to reach us:

USA/EUROPE/Locations Not Listed: Motorola Literature Distribution;

P.O. Box 20912; Phoenix, Arizona 85036. 1–800–441–2447 or 602–303–5454

JAPAN: Nippon Motorola Ltd.; Tatsumi–SPD–JLDC, 6F Seibu–Butsuryu–Center,

3–14–2 Tatsumi Koto–Ku, Tokyo 135, Japan. 03–81–3521–8315

MFAX: RMFAX0@email.sps.mot.com – TOUCHTONE 602–244–6609

INTERNET: http://Design–NET.com

ASIA/PACIFIC: Motorola Semiconductors H.K. Ltd.; 8B Tai Ping Industrial Park,

51 Ting Kok Road, Tai Po, N.T., Hong Kong. 852–26629298

MOTOROLA ANALOG IC DEVICE DATA

LP2950/D

◊

LP2951CD-5.0 [MOTOROLA]

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