LT1963_技术文档

LT3021/LT3021-1.2/

LT3021-1.5/LT3021-1.8

500mA, Low Voltage,

Very Low Dropout

Linear Regulator

U

DESCRIPTIO

FEATURES

The LT^®3021 is a very low dropout voltage (VLDO^TM) linear

regulator that operates from input supplies down to 0.9V.

This device supplies 500mA of output current with a

typical dropout voltage of 160mV. The LT3021 is ideal for

low input voltage to low output voltage applications,

providing comparable electrical efficiency to that of a

switching regulator.

■

V_INRange: 0.9V to 10V

■

Dropout Voltage: 160mV Typical

■

Output Current: 500mA

■

Adjustable Output (V_REF= V_OUT(MIN)= 200mV)

■

Fixed Output Voltages: 1.2V, 1.5V, 1.8V

■

Stable with Low ESR, Ceramic Output Capacitors

(3.3µF Minimum)

■

0.2% Load Regulation from 0mA to 500mA

The LT3021 regulator optimizes stability and transient

response with low ESR, ceramic output capacitors as

small as 3.3µF. Other LT3021 features include 0.05%

typical line regulation and 0.2% typical load regulation. In

shutdown, quiescent current typically drops to 3µA.

■

Quiescent Current: 120µA (Typ)

■

3µA Typical Quiescent Current in Shutdown

■

Current Limit Protection

■

Reverse-Battery Protection

■

No Reverse Current

■

Internal protection circuitry includes reverse-battery pro-

tection, current limiting, thermal limiting with hysteresis,

andreverse-currentprotection. TheLT3021isavailableas

an adjustable output device with an output range down to

the 200mV reference. Three fixed output voltages, 1.2V,

1.5V and 1.8V, are also available.

Thermal Limiting with Hysteresis

■

16-Pin DFN (5mm × 5mm) and 8-Lead

SO Packages

U

APPLICATIO S

■

Low Current Regulators

The LT3021 regulator is available in the low profile

(0.75mm) 16-pin (5mm × 5mm) DFN package with ex-

posed pad and the 8-lead SO package.

, LTC and LT are registered trademarks of Linear Technology Corporation. VLDO is a

trademark of Linear Technology Corporation. All other trademarks are the property of their

respective owners.

■

Battery-Powered Systems

■

Cellular Phones

■

Pagers

■

Wireless Modems

U

TYPICAL APPLICATIO

Minimum Input Voltage

1.8V to 1.5V, 500mA VLDO Regulator

1.1

I

L

= 500mA

1.0

0.9

0.8

0.7

0.6

0.5

0.4

0.3

0.2

0.1

0

V

OUT

V

IN

OUT

LT3021-1.5

1.5V

1.8V

500mA

3.3µF

SHDN SENSE

GND

3021 TA01

–50 –25

0

25

50

75 100 125

TEMPERATURE (°C)

3021 TA02

3021fa

1

LT3021/LT3021-1.2/

LT3021-1.5/LT3021-1.8

W W

U W

ABSOLUTE AXI U RATI GS

(Note 1)

IN Pin Voltage........................................................ ±10V

OUT Pin Voltage .................................................... ±10V

Input-to-Output Differential Voltage....................... ±10V

ADJ/SENSE Pin Voltage ........................................ ±10V

SHDN Pin Voltage................................................. ±10V

Output Short-Circut Duration.......................... Indefinite

Operating Junction Temperature Range

(Notes 2, 3) .......................................... –40°C to 125°C

Storage Temperature Range

DH .................................................... –65°C to 125°C

S8..................................................... –65°C to 150°C

Lead Temperature (Soldering, 10 sec).................. 300°C

U W

U

PACKAGE/ORDER I FOR ATIO

TOP VIEW

ORDER PART

NUMBER

DH PART

MARKING

NC

1

2

3

4

5

6

7

8

16 NC

15 NC

14 IN

NC

1

2

3

4

5

6

7

8

16 NC

15 NC

14 IN

3021

LT3021EDH

OUT

NC

OUT

NC

13 NC

12 IN

13 NC

12 IN

17

NC

11 NC

10 PGND

NC

11 NC

10 PGND

ADJ

AGND

SENSE

AGND

ORDER PART

NUMBER

DH PART

MARKING

9

SHDN

9

SHDN

LT3021-ADJ

DH PACKAGE

16-LEAD (5mm × 5mm) PLASTIC DFN

LT3021-FIXED

DH PACKAGE

16-LEAD (5mm × 5mm) PLASTIC DFN

LT3021EDH-1.2

LT3021EDH-1.5

LT3021EDH-1.8

302112

302115

302118

T_JMAX= 125°C, θ_JA= 35°C/ W*, θ_JC= 3°C/ W**

EXPOSED PAD IS GND (PIN 17) CONNECT TO PINS 8, 10 EXPOSED PAD IS GND (PIN 17) CONNECT TO PINS 8, 10

*SEE THE APPLICATIONS INFORMATION SECTION

**MEASURED JUNCTION TO PIN 17

T_JMAX= 125°C, θ_JA= 35°C/ W*, θ_JC= 3°C/ W**

*SEE THE APPLICATIONS INFORMATION SECTION

**MEASURED JUNCTION TO PIN 17

ORDER PART

NUMBER

S8 PART

TOP VIEW

MARKING

NC

OUT

1

2

3

4

8

7

6

5

IN

NC

OUT

1

2

3

4

8

7

6

5

IN

3021

LT3021ES8

NC

ADJ

PGND

SHDN

SENSE

AGND

PGND

SHDN

AGND

ORDER PART

NUMBER

S8 PART

MARKING

LT3021-ADJ

LT3021-FIXED

S8 PACKAGE

8-LEAD PLASTIC SO

T_JMAX= 150°C, θ_JA= 125°C/ W*, θ_JC= 40°C/ W**

*SEE THE APPLICATIONS INFORMATION SECTION

**MEASURED JUNCTION TO PIN 6

T_JMAX= 150°C, θ_JA= 125°C/ W*, θ_JC= 40°C/ W**

*SEE THE APPLICATIONS INFORMATION SECTION

**MEASURED JUNCTION TO PIN 6

LT3021ES8-1.2

LT3021ES8-1.5

LT3021ES8-1.8

302112

302115

302118

Order Options Tape and Reel: Add #TR

Lead Free: Add #PBF Lead Free Tape and Reel: Add #TRPBF

Lead Free Part Marking: http://www.linear.com/leadfree/

Consult factory for parts specified with wider operating temperature ranges.

3021fa

2

LT3021/LT3021-1.2/

LT3021-1.5/LT3021-1.8

ELECTRICAL CHARACTERISTICS

The

●

denotes specifications which apply over the full operating temperature range, otherwise specifications are T = 25°C.

J

PARAMETER

CONDITIONS

MIN

TYP

MAX

UNITS

Minimum Input Voltage

(Notes 5,14)

I

= 500mA, T > 0°C

0.9

1.05

1.10

V

LOAD

J

= 500mA, T < 0°C

J

ADJ Pin Voltage (Notes 4, 5)

V

= 1.5V, I

= 1mA

LOAD

196

193

200

204

206

mV

IN

1.15V < V < 10V, 1mA < I

< 500mA

●

IN

LOAD

Regulated Output Voltage

(Note 4)

LT3021-1.2

LT3021-1.5

LT3021-1.8

V

IN

= 1.5V, I

= 1mA

LOAD

1.176

1.157

1.200

1.224

1.236

V

1.5V < V < 10V, 1mA < I

< 500mA

IN

LOAD

V

IN

= 1.8V, I

= 1mA

LOAD

1.470

1.447

1.500

1.530

1.545

V

1.8V < V < 10V, 1mA < I

IN

V

IN

= 2.1V, I

= 1mA

LOAD

1.764

1.737

1.800

1.836

1.854

V

2.1V < V < 10V, 1mA < I

IN

Line Regulation (Note 6)

Load Regulation (Note 6)

Dropout Voltage (Notes 7, 12)

LT3021

∆V = 1.15V to 10V, I

= 1mA

●

–1.75

–10.5

–13

0

+1.75

10.5

13

mV

IN

LOAD

LT3021-1.2

LT3021-1.5

LT3021-1.8

∆V = 1.5V to 10V, I

= 1mA

IN

LOAD

∆V = 1.8V to 10V, I

IN

∆V = 2.1V to 10V, I

–15.8

15.8

IN

LT3021

V

IN

V

IN

V

IN

V

IN

= 1.15V, ∆I

= 1mA to 500mA

LOAD

–2

–6

–7.5

–9

0.4

1

1.5

2

6

7.5

9

mV

LT3021-1.2

LT3021-1.5

LT3021-1.8

= 1.5V, ∆I

= 1.8V, ∆I

= 2.1V, ∆I

= 1mA to 500mA

LOAD

I

= 10mA

45

75

110

mV

LOAD

●

I

= 500mA

155

190

285

mV

LOAD

●

GND Pin Current

I

= 0mA

110

920

2.25

6.20

250

µA

mA

LOAD

V

IN

= V

+ 0.4V

= 10mA

= 100mA

= 500mA

OUT(NOMINAL)

(Notes 8, 12)

●

10

Output Voltage Noise

ADJ Pin Bias Current

Shutdown Threshold

C

V

= 4.7µF, I

= 500mA, BW = 10Hz to 100kHz, V

= 1.2V

300

20

µV

RMS

OUT

ADJ

LOAD

OUT

= 0.2V, V = 1.2V (Notes 6, 9)

50

nA

IN

V

OUT

V

OUT

= Off to On

= On to Off

●

0.61

0.9

V

0.25

SHDN Pin Current (Note 10)

V

= 0V, V = 10V

●

±1

µA

SHDN

IN

= 10V, V = 10V

3

9.5

IN

Quiescent Current in Shutdown

Ripple Rejection (Note 6)

V

IN

= 6V, V

= 0V

9

SHDN

LT3021

V

IN

– V

= 1V, V = 0.5V , f = 120Hz,

P-P RIPPLE

70

dB

OUT

RIP

I

= 500mA

LOAD

LT3021-1.2

LT3021-1.5

LT3021-1.8

V

– V

= 500mA

= 1V, V

= 0.5V , f = 120Hz,

P-P RIPPLE

60

58

56

dB

IN

OUT

RIPPLE

I

LOAD

V

IN

– V

= 500mA

= 1V, V

= 0.5V , f

P-P RIPPLE

= 120Hz,

OUT

I

LOAD

V

IN

– V

= 500mA

= 1V, V

= 0.5V , f

P-P RIPPLE

OUT

I

LOAD

3021fa

3

LT3021/LT3021-1.2/

LT3021-1.5/LT3021-1.8

ELECTRICAL CHARACTERISTICS

The

●

denotes specifications which apply over the full operating temperature range, otherwise specifications are T = 25°C.

J

PARAMETER

CONDITIONS

MIN

TYP

MAX

UNITS

Current Limit (Note 12)

V

= 10V, V

= V

= 0V

1.8

A

mA

IN

OUT

OUT(NOMINAL)

+ 0.5V, ∆V

= –5%

●

550

OUT

Input Reverse Leakage Current

V

= –10V, V = 0V

OUT

1

20

µA

IN

Reverse Output Current

(Notes 11, 13)

LT3021

V

= 1.2V, V = 0V

0.5

10

5

µA

OUT

IN

LT3021-1.2

LT3021-1.5

LT3021-1.8

= 1.2V, V = 0V

15

IN

= 1.5V, V = 0V

IN

= 1.8V, V = 0V

IN

Note 7: Dropout voltage is the minimum input to output voltage differential

Note 1: Absolute Maximum Ratings are those values beyond which the life

needed to maintain regulation at a specified output current. In dropout the

of a device may be impaired.

output voltage equals: (V – V

).

IN

DROPOUT

Note 2: The LT3021 regulators are tested and specified under pulse load

Note 8: GND pin current is tested with V = V

+ 0.4V and a

OUT(NOMINAL)

conditions such that T ≈ T . The LT3021 is 100% production tested at

IN

J

A

current source load. GND pin current will increase in dropout. See GND

pin current curves in the Typical Performance Characteristics section.

T = 25°C. Performance at –40°C and 125°C is assured by design,

A

characterization and correlation with statistical process controls.

Note 9: Adjust pin bias current flows out of the ADJ pin.

Note 10: Shutdown pin current flows into the SHDN pin.

Note 11: Reverse output current is tested with IN grounded and OUT

forced to the rated output voltage. This current flows into the OUT pin and

out of the GND pin. For fixed voltage devices this includes the current in

the output resistor divider.

Note 3: This IC includes overtemperature protection that is intended to

protect the device during momentary overload conditions. Junction

temperature will exceed 125°C when overtemperature protection is active.

Continuous operation above the specified maximum operating junction

temperature may impair device reliability.

Note 4: Maximum junction temperature limits operating conditions. The

regulated output voltage specification does not apply for all possible

combinations of input voltage and output current. Limit the output current

range if operating at maximum input voltage. Limit the input voltage range

if operating at maximum output current.

Note 12: The LT3021 is tested and specified for these conditions with an

external resistor divider (20k and 100k) setting V

to 1.2V. The external

OUT

resistor divider adds 10µA of load current.

Note 13: Reverse current is higher for the case of (rated_output) < V

<

OUT

Note 5: Typically the LT3021 supplies 500mA output current with a 1V

input supply. The guranteed minimum input voltage for 500mA output

current is 1.10V.

V

because the no-load recovery circuitry is active in this region and is

IN,

trying to restore the output voltage to its nominal value.

Note 14: Minimum input voltage is the minimum voltage required by the

control circuit to regulate the output voltage and supply the full 500mA

Note 6: The LT3021 is tested and specified for these conditions with an

external resistor divider (20k and 30.1k) setting V

to 0.5V. The external

OUT

rated current. This specification is tested at V

= 0.5V. At higher output

OUT

resistor divider adds 10µA of output load current. The line regulation and

load regulation specifications refer to the change in the 0.2V reference

voltage, not the 0.5V output voltage. Specifications for fixed output voltage

devices are referred to the output voltage.

voltages the minimum input voltage required for regulation will be equal to

the regulated output voltage V

plus the dropout voltage.

OUT

U W

TYPICAL PERFOR A CE CHARACTERISTICS

Dropout Voltage

Minimum Input Voltage

250

225

200

175

150

125

100

75

250

225

200

175

150

125

100

75

1.2

1.1

1.0

0.9

0.8

0.7

0.6

0.5

0.4

0.3

0.2

V

= 1.2V

I

L

= 500mA

OUT

I

= 500mA

L

T

= 125°C

J

I

= 250mA

= 100mA

L

T

J

= 25°C

I

= 50mA

I = 10mA

L

50

25

I

= 1mA

L

0

100

200

300

400

500

–50 –25

0

25

50

75 100 125

–50 –25

0

25

50

75 100 125

OUTPUT CURRENT (mA)

TEMPERATURE (°C)

3021 G01

3021 G02

3021 G16

3021fa

4

LT3021/LT3021-1.2/

LT3021-1.5/LT3021-1.8

U W

TYPICAL PERFOR A CE CHARACTERISTICS

ADJ Pin Voltage

ADJ Pin Bias Current

Quiescent Current

206

204

202

200

198

196

194

25

20

15

10

5

250

V

I

= 6V

OUT

= 0

IN

= 1.2V

225

200

175

150

125

100

75

L

V

= V

IN

SHDN

50

25

V

= 0V

SHDN

0

–50 –25

0

25

50

75 100 125

–50 –25

0

25

50

75 100 125

–50 –25

0

25

50

75 100 125

TEMPERATURE (°C)

3021 G04

3021 G11

3021 G05

Output Voltage

1.53

1.52

1.51

1.50

1.49

1.48

1.47

1.83

1.82

1.81

1.80

1.79

1.78

1.77

1.23

1.22

1.21

1.20

1.19

1.18

1.17

I

= 1mA

I

= 1mA

I

= 1mA

LOAD

50

TEMPERATURE (°C)

100 125

50

TEMPERATURE (°C)

100 125

–50 –25

0

25

75

–50 –25

0

25

75

50

TEMPERATURE (°C)

100 125

–50 –25

0

25

75

3021 G23

3021 G22

3021 G28

Quiescent Current

3.0

2.5

2.0

1.5

1.0

0.5

0

3.0

2.5

2.0

1.5

1.0

0.5

0

3.0

2.5

2.0

1.5

1.0

0.5

0

V

I

= 1.8V

V

I

J

= 1.2V

V

I

J

= 1.5V

OUT

= 0

OUT

= 0

OUT

= 0

L

T = 25°C

J

T

= 25°C

T

= 25°C

V

= V

IN

V

SHDN

= V

IN

V

= V

SHDN

IN

V

= 0V

7

V

= 0V

7

SHDN

6

V

= 0V

SHDN

6

SHDN

0

1

2

3

4

5

8

9

10

0

1

2

3

4

5

6

7

8

9

10

0

1

2

3

4

5

8

9

10

INPUT VOLTAGE (V)

3021 G03

3021 G27

3021 G26

3021fa

5

LT3021/LT3021-1.2/

LT3021-1.5/LT3021-1.8

U W

TYPICAL PERFOR A CE CHARACTERISTICS

GND Pin Current

8

7

6

5

4

3

2

1

0

8

7

6

5

4

3

2

1

0

9

8

7

6

5

4

3

2

1

0

V

T

= 1.5V

V

T

= 1.2V

V

T

= 1.8V

OUT

J

OUT

J

OUT

J

R

L

= 2.4Ω

= 25°C

L

= 25°C

R

L

= 3Ω

L

= 25°C

I

= 500mA

I

= 500mA

R

L

= 3.6Ω

L

I

= 500mA

R

= 4.8Ω

= 250mA

L

R

L

= 6Ω

= 250mA

L

R

L

= 7.2Ω

L

I

L

I

R

L

= 24Ω

R

L

= 30Ω

L

R

L

= 36Ω

I

= 250mA

L

R

= 120Ω

= 10mA

R = 150Ω

L

= 10mA

L

R

L

= 180Ω

I

= 50mA

I

= 50mA

I

= 50mA

L

I

L

I

L

I

= 10mA

R

L

= 12Ω

= 100mA

R

L

= 18Ω

L

R

L

= 15Ω

L

I

= 100mA

I

= 100mA

R

= 1.5k, I = 1mA

L

R

= 1.8k, I = 1mA

L

R

= 1.2k, I = 1mA

L

0

1

2

3

4

5

6

7

8

9

10

0

1

2

3

4

5

6

7

8

9

10

0

1

2

3

4

5

6

7

8

9

10

INPUT VOLTAGE (V)

3021 G06

3021 G24

3021 G25

GND Pin Current vs I

SHDN Pin Threshold

SHDN Pin Input Current

LOAD

10

9

8

7

6

5

4

3

2

1

0

1.0

0.9

0.8

0.7

0.6

0.5

0.4

0.3

0.2

0.1

0

5.0

4.5

4.0

3.5

3.0

2.5

2.0

1.5

1.0

0.5

0

V

= 10V

I = 1mA

L

SHDN

0

100

200

300

400

500

–50 –25

0

25

50

75 100 125

0

1

2

3

4

5

6

7

8

9

10

LOAD CURRENT (mA)

TEMPERATURE (°C)

SHDN PIN VOLTAGE (V)

3021 G07

3021 G08

3021 G09

Reverse Output Current

SHDN Pin Input Current

Current Limit

2.0

1.8

1.6

1.4

1.2

1.0

0.8

0.6

0.4

0.2

0

5

4

3

2

1

0

500

450

400

350

300

250

200

150

100

50

V

= 0V

V

= 10V

V

= 0V

OUT

SHDN

IN

OUT

= 1.2V

V

= 10V

IN

V

= 1.7V

IN

0

–50 –25

0

25

50

75 100 125

–50 –25

0

25

50

75 100 125

–50 –25

0

25

50

75 100 125

TEMPERATURE (°C)

3021 G12

3021 G10

3021 G13

3021fa

6

LT3021/LT3021-1.2/

LT3021-1.5/LT3021-1.8

U W

TYPICAL PERFOR A CE CHARACTERISTICS

Load Regulation

L

Input Ripple Rejection

∆I = 1mA to 500mA

70

60

50

40

30

20

10

0

100

90

80

70

60

50

40

30

20

10

0

2.5

2.0

1.5

C

= 22µF

= 4.7µF

OUT

1.0

0.5

0

–0.5

–1.0

–1.5

–2.0

–2.5

C

OUT

V

= 1.15V

OUT

IN

= 0.5V

V

I

= 1.5V + 0.5V RIPPLE AT 120Hz

P-P

V

I

= 1.5V + 50mV

= 0.5V

RIPPLE

10k

IN

OUT

L

IN

OUT

RMS

*LOAD REGULATION NUMBER REFERS

TO CHANGE IN THE 200mV REFERENCE

VOLTAGE

= 0.5V

= 500mA

L

10

100

1k

100k

1M

–50 –25

0

25

50

75 100 125

–50 –25

0

25

50

75 100 125

FREQUENCY (Hz)

TEMPERATURE (°C)

3021 G14

3021 G15

3021 G17

Output Noise Spectral Density

No-Load Recovery Threshold

10

1

18

16

14

12

10

8

V

L

C

= 1.2V

OUT

I

= 500mA

= 4.7µF

OUT

0.1

6

4

2

0.01

0

10

100

1k

10k

100k

1M

0

5

10

15

20

FREQUENCY (Hz)

OUTPUT OVERSHOOT (%)

3021 G20

3021 G18

RMS Output Noise vs Load

Current (10Hz to 100kHz)

Transient Response

300

250

200

150

100

50

V

C

= 1.2V

= 4.7µF

OUT

V

OUT

50mV/DIV

I

OUT

500mA/DIV

50µs/DIV

3021 G21

I

= 50mA TO 500mA

= 1.5V

OUT

IN

V

C

0

0.01

0.1

1

10

100

= 1.2V

OUT

LOAD CURRENT (mA)

= 22µF

3021 G19

3021fa

7

LT3021/LT3021-1.2/

LT3021-1.5/LT3021-1.8

U

PI FU CTIO S

(DH Package/S8 Package)

OUT(Pins3,4/Pin2):Thesepinssupplypowertotheload.

Use a minimum output capacitor of 3.3µF to prevent oscil-

lations.Applicationswithlargeloadtransientsrequirelarger

output capacitors to limit peak voltage transients. See the

Applications Information section for more information on

output capacitance and reverse output characteristics.

resistor supplies the pull-up current to the open collector/

drainlogic,normallyseveralmicroamperes,andtheSHDN

pin current, typically 2.5µA. If unused, connect the SHDN

pin to V_IN. The LT3021 does not function if the SHDN pin

is not connected.

IN (Pins 12, 14/Pin 8): These pins supply power to the

device. The LT3021 requires a bypass capacitor at IN if it

is more than six inches away from the main input filter

capacitor.Theoutputimpedanceofabatteryriseswithfre-

quency, so include a bypass capacitor in battery-powered

circuits. A bypass capacitor in the range of 3.3µF to 10µF

suffices. The LT3021 withstands reverse voltages on the

IN pin with respect to ground and the OUT pin. In the case

of a reversed input, which occurs if a battery is plugged in

backwards, the LT3021 acts as if a diode is in series with

its input. No reverse current flows into the LT3021 and no

reversevoltageappearsattheload.Thedeviceprotectsitself

and the load.

SENSE(Pin7/Pin3, FixedVoltageDeviceOnly):Thispin

is the sense point for the internal resistor divider. It should

be tied directly to the OUT pins (1, 2) for best results.

ADJ (Pin 7/Pin 3): This pin is the inverting terminal to the

error amplifier. Its typical input bias current of 20nA flows

out of the pin (see curve of ADJ Pin Bias Current vs

Temperature in the Typical Performance Characteristics).

TheADJpinreferencevoltageis200mV(referredtoGND).

AGND (Pin 8/Pin 4): Ground.

PGND (Pins 10, 17/Pin 6): Ground.

SHDN (Pin 9/Pin 5): The SHDN pin puts the LT3021 into

a low power state. Pulling the SHDN pin low turns the

output off. Drive the SHDN pin with either logic or an open

collector/drain device with a pull-up resistor. The pull-up

EXPOSED PAD (Pin 17, DH16 Package Only): Ground.

Solder Pin 17 to the PCB ground. Connect directly to Pins

5, 8, 10 for best performance.

NC (Pins 1, 2, 5, 6, 11, 15, 16/Pins 1, 7)

W

BLOCK DIAGRA

(DH Package/S8 Package)

IN

(12, 14/8)

R3

THERMAL

SHUTDOWN

SHDN

(9/5)

SHUTDOWN

D1

Q3

–

CURRENT

Q1

ERROR AMP

+

GAIN

200mV

BIAS CURRENT

AND

REFERENCE

GENERATOR

OUT

D2

(3,4/2)

OUT SENSE

(7/3)

212mV

–

NO-LOAD

RECOVERY

Q2

R2

+

ADJ

(7/3)

25k

R1

FIXED

OUT

NOTE:

V

R1

R2

FOR LT3021 ADJUST PIN (7/3) IS CONNECTED TO

THE ADJUST PIN, R1 AND R2 ARE EXTERNAL.

FOR LT3021-1.X PIN (7/3) IS CONNECTED TO THE

OUTPUT SENSE PIN, R1 AND R2 ARE INTERNAL.

1.2V 20k 100k

1.5V 20k 130k

1.8V 20k 160k

GND

(8,10,17/4,6)

3021 BD

3021fa

8

LT3021/LT3021-1.2/

LT3021-1.5/LT3021-1.8

W U U

APPLICATIO S I FOR ATIO

U

The LT3021 is a very low dropout linear regulator capable

of 1V input supply operation. Devices supply 500mA of

output current and dropout voltage is typically 155mV.

Quiescent current is typically 120µA and drops to 3µA in

shutdown. The LT3021 incorporates several protection

features, making it ideal for use in battery-powered sys-

tems. The device protects itself against reverse-input and

reverse-output voltages. In battery backup applications

where the output is held up by a backup battery when the

input is pulled to ground, the LT3021 acts as if a diode is

in series with its output which prevents reverse current

flow. In dual supply applications where the regulator load

is returned to a negative supply, the output can be pulled

below ground by as much as 10V without affecting start-

up or normal operation.

0.4mVatV_ADJ=200mV. AtV_OUT=1.5V, loadregulationis:

(1.5V/200mV) • (0.4mV) = 3mV

Output Capacitance and Transient Response

The LT3021’s design is stable with a wide range of output

capacitors, but is optimized for low ESR ceramic capaci-

tors. The output capacitor’s ESR affects stability, most

notably with small value capacitors. Use a minimum

output capacitor of 3.3µF with an ESR of 0.2Ω or less to

prevent oscillations. The LT3021 is a low voltage device,

and output load transient response is a function of output

capacitance.Largervaluesofoutputcapacitancedecrease

the peak deviations and provide improved transient re-

sponse for larger load current changes. For output capaci-

torvaluesgreaterthan22µFasmallfeedforwardcapacitor

with a value of 300pF across the upper divider resistor (R2

in Figure 1) is required. Under extremely low output

current conditions (I_LOAD< 30µA) a low frequency small

signal oscillation (200Hz/8mV_P-Pat 1.2V output) can

occur. A minimum load of 100µA is recommended to

prevent this instability.

Adjustable Operation

The LT3021’s output voltage range is 0.2V to 9.5V. Figure

1 shows that the output voltage is set by the ratio of two

external resistors. The device regulates the output to

maintain the ADJ pin voltage at 200mV referenced to

ground. The current in R1 equals 200mV/R1 and the

current in R2 is the current in R1 minus the ADJ pin bias

current. The ADJ pin bias current of 20nA flows out of the

pin.UsetheformulainFigure1tocalculateoutputvoltage.

An R1 value of 20k sets the resistor divider current to

10µA. Note that in shutdown the output is turned off and

the divider current is zero. Curves of ADJ Pin Voltage vs

Temperature and ADJ Pin Bias Current vs Temperature

appearintheTypicalPerformanceCharacteristicssection.

Give extra consideration to the use of ceramic capacitors.

Manufacturers make ceramic capacitors with a variety of

dielectrics, each with a different behavior across tempera-

tureandappliedvoltage.Themostcommondielectricsare

Z5U, Y5V, X5R and X7R. The Z5U and Y5V dielectrics

provide high C-V products in a small package at low cost,

but exhibit strong voltage and temperature coefficients.

The X5R and X7R dielectrics yield highly stable

characterisiticsandaremoresuitableforuseastheoutput

capacitor at fractionally increased cost. The X5R and X7R

dielectrics both exhibit excellent voltage coefficient char-

acteristics. The X7R type works over a larger temperature

range and exhibits better temperature stability whereas

X5R is less expensive and is available in higher values.

Figures 2 and 3 show voltage coefficient and temperature

coefficient comparisons between Y5V and X5R material.

IN

OUT

ADJ

V

OUT

+

V

LT3021

SHDN

GND

IN

R2

R1

3021 F01

(R2)

R2

V

= 200mV 1 +

– I

ADJ

OUT

ADJ

(

)

R1

V

= 200mV

I

= 20nA AT 25°C

ADJ

Voltage and temperature coefficients are not the only

sources of problems. Some ceramic capacitors have a

piezoelectric response. A piezoelectric device generates

voltageacrossitsterminalsduetomechanicalstress,simi-

lartothewayapiezoelectricaccelerometerormicrophone

works. For a ceramic capacitor, the stress can be induced

by vibrations in the system or thermal transients. The re-

OUTPUT RANGE = 0.2V TO 9.5V

Figure 1. Adjustable Operation

Specifications for output voltages greater than 200mV are

proportional to the ratio of desired output voltage to

200mV; (V_OUT/200mV). For example, load regulation for

an output current change of 1mA to 500mA is typically

sultingvoltagesproducedcancauseappreciableamounts

3021fa

9

LT3021/LT3021-1.2/

LT3021-1.5/LT3021-1.8

W U U

U

APPLICATIO S I FOR ATIO

20

BOTH CAPACITORS ARE 16V,

1210 CASE SIZE, 10µF

0

X5R

–20

1mV/DIV

–40

–60

Y5V

–80

–100

V

C

LOAD

= 1.3V

= 10µF

= 0

1ms/DIV

3021 F04

OUT

0

8

12 14

2

4

6

10

16

DC BIAS VOLTAGE (V)

I

3021 F02

Figure 4. Noise Resulting from Tapping on a Ceramic Capacitor

Figure 2. Ceramic Capacitor DC Bias Characteristics

To eliminate this problem, the LT3021 incorporates a

no-load or light-load recovery circuit. This circuit is a

voltage-controlledcurrentsinkthatsignificantlyimproves

the light load transient response time by discharging the

output capacitor quickly and then turning off. The current

sink turns on when the output voltage exceeds 6% of the

nominal output voltage. The current sink level is then

proportional to the overdrive above the threshold up to a

maximum of approximately 15mA. Consult the curve in

the Typical Performance Characteristics for the No-Load

Recovery Threshold.

40

20

X5R

0

–20

–40

Y5V

–60

–80

BOTH CAPACITORS ARE 16V,

1210 CASE SIZE, 10µF

–100

–50 –25

0

25

50

75

100 125

TEMPERATURE (°C)

3021 F03

If external circuitry forces the output above the no load

recoverycircuit’sthreshold, thecurrentsinkturnsoninan

attempt to restore the output voltage to nominal. The

currentsinkremainsonuntiltheexternalcircuitryreleases

the output. However, if the external circuitry pulls the

output voltage above the input voltage, or the input falls

belowtheoutput,theLT3021turnsthecurrentsinkoffand

shuts down the bias current/reference generator circuitry.

Figure 3. Ceramic Capacitor Temperature Characteristics

of noise. A ceramic capacitor produced Figure 4’s trace in

response to light tapping from a pencil. Similar vibration

induced behavior can masquerade as increased output

voltage noise.

No-Load/Light-Load Recovery

Thermal Considerations

A transient load step occurs when the output current

changes from its maximum level to zero current or a very

small load current. The output voltage responds by over-

shooting until the regulator lowers the amount of current it

delivers to the new level. The regulator loop response time

andtheamountofoutputcapacitancecontroltheamountof

overshoot. Once the regulator has decreased its output

current, the current provided by the resistor divider (which

sets V_OUT) is the only current remaining to discharge the

output capacitor from the level to which it overshot. The

amount of time it takes for the output voltage to recover

easilyextendstomillisecondswithmicroamperesofdivider

current and a few microfarads of output capacitance.

The LT3021’s power handling capability is limited by its

maximumratedjunctiontemperatureof125°C.Thepower

dissipated by the device is comprised of two components:

1. Output current multiplied by the input-to-output volt-

age differential: (I_OUT)(V_IN– V_OUT) and

2. GND pin current multiplied by the input voltage:

(I_GND)(V_IN).

GND pin current is found by examining the GND pin

currentcurvesintheTypicalPerformanceCharacteristics.

Power dissipation is equal to the sum of the two compo-

nents listed above.

3021fa

10

LT3021/LT3021-1.2/

LT3021-1.5/LT3021-1.8

W U U

APPLICATIO S I FOR ATIO

U

The LT3021 regulator has internal thermal limiting (with

hysteresis)designedtoprotectthedeviceduringoverload

conditions. For normal continuous conditions, do not

exceedthemaximumjunctiontemperatureratingof125°C.

Carefully consider all sources of thermal resistance from

junction to ambient including other heat sources mounted

in proximity to the LT3021.

Calculating Junction Temperature

Example: Given an output voltage of 1.2V, an input voltage

range of 1.8V ±10%, an output current range of 1mA to

500mA, and a maximum ambient temperature of 70°C,

what will the maximum junction temperature be for an

application using the DH package?

The power dissipated by the device is equal to:

TheundersideoftheLT3021DHpackagehasexposedmetal

(14mm²) from the lead frame to where the die is attached.

This allows heat to directly transfer from the die junction

to the printed circuit board metal to control maximum

operating junction temperature. The dual-in-line pin ar-

rangement allows metal to extend beyond the ends of the

package on the topside (component side) of a PCB. Con-

nectthismetaltoGNDonthePCB.ThemultipleINandOUT

pinsoftheLT3021alsoassistinspreadingheattothePCB.

I_OUT(MAX)(V_IN(MAX)– V_OUT) + I_GND(V_IN(MAX)

where

)

I_OUT(MAX)= 500mA

V_IN(MAX)= 1.98V

I_GNDat (I_OUT= 500mA, V_IN= 1.98V) = 10mA

so

The LT3021 S8 package has pin 4 fused with the lead

frame. This also allows heat to transfer from the die to the

printedcircuitboardmetal, thereforereducingthethermal

resistance. Copper board stiffeners and plated through-

holes can also be used to spread the heat generated by

power devices.

P = 500mA(1.98V – 1.2V) + 10mA(1.98V) = 0.41W

The thermal resistance is in the range of 35°C/W to

70°C/W depending on the copper area. So the junction

temperatureriseaboveambientisapproximatelyequalto:

0.41W(52.5°C/W) = 21.5°C

The maximum junction temperature equals the maximum

junction temperature rise above ambient plus the maxi-

mum ambient temperature or:

The following tables list thermal resistance for several

different board sizes and copper areas for two different

packages. Measurements were taken in still air on 3/32"

FR-4 board with one ounce copper.

T_JMAX= 21.5°C + 70°C = 91.5°C

Table 1. Measured Thermal Resistance For DH Package

Protection Features

COPPER AREA

THERMAL RESISTANCE

TOPSIDE*

2500mm²

900mm²

225mm²

100mm²

50mm²

BACKSIDE BOARD AREA (JUNCTION-TO-AMBIENT)

The LT3021 incorporates several protection features that

make it ideal for use in battery-powered circuits. In addi-

tion to the normal protection features associated with

monolithic regulators, such as current limiting and ther-

mal limiting, the device also protects against reverse-

input voltages, reverse-output voltages and reverse

output-to-input voltages.

2500mm²

30°C/W

35°C/W

50°C/W

55°C/W

65°C/W

Table 2. Measured Thermal Resistance For S8 Package

Current limit protection and thermal overload protection

protect the device against current overload conditions at

the output of the device. For normal operation, do not

exceed a junction temperature of 125°C.

COPPER AREA

TOPSIDE* BACKSIDE

THERMAL RESISTANCE

BOARD AREA (JUNCTION-TO-AMBIENT)

2500mm²

1000mm²

225mm²

100mm²

50mm²

2500mm²

70°C/W

78°C/W

84°C/W

96°C/W

The IN pins of the device withstand reverse voltages of

10V. The LT3021 limits current flow to less than 1µA and

no negative voltage appears at OUT. The device protects

both itself and the load against batteries that are plugged

*Device is mounted on topside.

in backwards.

3021fa

11

LT3021/LT3021-1.2/

LT3021-1.5/LT3021-1.8

W U U

U

APPLICATIO S I FOR ATIO

The LT3021 incurs no damage if OUT is pulled below

ground. If IN is left open circuit or grounded, OUT can be

pulled below ground by 10V. No current flows from the

pass transistor connected to OUT. However, current flows

in(butislimitedby)theresistordividerthatsetstheoutput

voltage. Current flows from the bottom resistor in the

divider and from the ADJ pin’s internal clamp through the

top resistor in the divider to the external circuitry pulling

OUT below ground. If IN is powered by a voltage source,

OUT sources current equal to its current limit capability

and the LT3021 protects itself by thermal limiting. In this

case, grounding SHDN turns off the LT3021 and stops

OUT from sourcing current.

circuit. In the case where the input is grounded, there is

less than 1µA of reverse output current.

IftheLT3021INpinisforcedbelowtheOUTpinortheOUT

pin is pulled above the IN pin, input current drops to less

than 10µA typically. This occurs if the LT3021 input is

connected to a discharged (low voltage) battery and either

a backup battery or a second regulator circuit holds up the

output. The state of the SHDN pin has no effect on the

reverse output current if OUT is pulled above IN.

Input Capacitance and Stability

The LT3021 is designed to be stable with a minimum

capacitance of 3.3µF placed at the IN pin. Ceramic capaci-

tors with very low ESR may be used. However, in cases

where a long wire is used to connect a power supply to the

input of the LT3021 (and also from the ground of the

LT3021 back to the power supply ground), use of low

value input capacitors combined with an output load

current of 20mA or greater may result in an unstable

application. This is due to the inductance of the wire

forming an LC tank circuit with the input capacitor and not

a result of the LT3021 being unstable.

The LT3021 incurs no damage if the ADJ pin is pulled

above or below ground by 10V. If IN is left open circuit or

grounded and ADJ is pulled above ground, ADJ acts like a

25k resistor in series with a 1V clamp (one Schottky diode

in series with one diode). ADJ acts like a 25k resistor in

series with a Schottky diode if pulled below ground. If IN

is powered by a voltage source and ADJ is pulled below its

reference voltage, the LT3021 attempts to source its

current limit capability at OUT. The output voltage in-

creases to V_IN– V_DROPOUTwith V_DROPOUTset by whatever

load current the LT3021 supports. This condition can

potentially damage external circuitry powered by the

LT3021 if the output voltage increases to an unregulated

high voltage. If IN is powered by a voltage source and ADJ

is pulled above its reference voltage, two situations can

occur. If ADJ is pulled slightly above its reference voltage,

theLT3021turnsoffthepasstransistor, nooutputcurrent

is sourced and the output voltage decreases to either the

voltage at ADJ or less. If ADJ is pulled above its no load

recovery threshold, the no load recovery circuitry turns on

and attempts to sink current. OUT is actively pulled low

and the output voltage clamps at a Schottky diode above

ground. Please note that the behavior described above

applies to the LT3021 only. If a resistor divider is con-

nected under the same conditions, there will be additional

V/R current.

The self-inductance, or isolated inductance, of a wire is

directly proportional to its length. However, the diameter

of a wire does not have a major influence on its self-

inductance. For example, the self inductance of a 2-AWG

isolated wire with a diameter of 0.26 in. is about half the

inductance of a 30-AWG wire with a diameter of 0.01 in.

One foot of 30-AWG wire has 465nH of self inductance.

The overall self-inductance of a wire can be reduced in two

ways. One is to divide the current flowing towards the

LT3021 between two parallel conductors and flows in the

same direction in each. In this case, the farther the wires

are placed apart from each other, the more inductance will

be reduced, up to a 50% reduction when placed a few

inches apart. Splitting the wires basically connects two

equal inductors in parallel. However, when placed in close

proximity from each other, mutual inductance is added to

the overall self inductance of the wires. The most effective

way to reduce overall inductance is to place the forward

and return-current conductors (the wire for the input and

the wire for ground) in very close proximity. Two 30-AWG

wires separated by 0.02 in. reduce the overall self-induc-

tance to about one-fifth of a single isolated wire.

In circuits where a backup battery is required, several

different input/output conditions can occur. The output

voltage may be held up while the input is either pulled to

ground, pulledtosomeintermediatevoltageorisleftopen

3021fa

12

LT3021/LT3021-1.2/

LT3021-1.5/LT3021-1.8

W U U

APPLICATIO S I FOR ATIO

U

If the LT3021 is powered by a battery mounted in close

proximity on the same circuit board, a 3.3µF input capaci-

tor is sufficient for stability. However, if the LT3021 is

powered by a distant supply, use a larger value input

capacitor following the guideline of roughly 1µF (in addi-

tion to the 3.3µF minimum) per 8 inches of wire length. As

power supply output impedance may vary, the minimum

input capacitance needed to stabilize the application may

alsovary. Extracapacitancemayalsobeplaceddirectlyon

the output of the power supply; however, this will require

an order of magnitude more capacitance as opposed to

placingextracapacitanceincloseproximitytotheLT3021.

Furthermore, seriesresistancemaybeplacedbetweenthe

supply and the input of the LT3021 to stabilize the appli-

cation; as little as 0.1Ω to 0.5Ω will suffice.

3021fa

13

LT3021/LT3021-1.2/

LT3021-1.5/LT3021-1.8

U

PACKAGE DESCRIPTIO

DH Package

16-Lead Plastic DFN (5mm × 5mm)

(Reference LTC DWG # 05-08-1709)

0.70 ±0.05

5.50 ±0.05

4.10 ±0.05

3.45 ±0.05

(2 SIDES)

PACKAGE

OUTLINE

0.25 ± 0.05

0.50 BSC

4.10 ±0.05

(2 SIDES)

RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS

R = 0.115

TYP

0.40 ± 0.05

5.00 ±0.10

9

16

R = 0.20

TYP

3.45 ± 0.10

(2 SIDES)

5.00 ±0.10

PIN 1

TOP MARK

NOTCH

(SEE NOTE 6)

(DH16) DFN 0204

8

1

0.25 ± 0.05

0.75 ±0.05

0.200 REF

0.50 BSC

4.10 ±0.10

(2 SIDES)

0.00 – 0.05

BOTTOM VIEW—EXPOSED PAD

NOTE:

1. DRAWING PROPOSED TO BE MADE VARIATION OF VERSION (WJJD-1) IN JEDEC

PACKAGE OUTLINE MO-229

2. DRAWING NOT TO SCALE

3. ALL DIMENSIONS ARE IN MILLIMETERS

4. DIMENSIONS OF EXPOSED PAD ON BOTTOM OF PACKAGE DO NOT INCLUDE

MOLD FLASH. MOLD FLASH, IF PRESENT, SHALL NOT EXCEED 0.15mm ON ANY SIDE

5. EXPOSED PAD SHALL BE SOLDER PLATED

6. SHADED AREA IS ONLY A REFERENCE FOR PIN 1 LOCATION ON THE

TOP AND BOTTOM OF PACKAGE

3021fa

14

LT3021/LT3021-1.2/

LT3021-1.5/LT3021-1.8

U

PACKAGE DESCRIPTIO

S8 Package

8-Lead Plastic Small Outline (Narrow .150 Inch)

(Reference LTC DWG # 05-08-1610)

.189 – .197

(4.801 – 5.004)

.045 ±.005

NOTE 3

.050 BSC

7

5

8

6

.245

MIN

.160 ±.005

.150 – .157

(3.810 – 3.988)

NOTE 3

.228 – .244

(5.791 – 6.197)

.030 ±.005

TYP

1

3

4

2

RECOMMENDED SOLDER PAD LAYOUT

.010 – .020

(0.254 – 0.508)

× 45°

.053 – .069

(1.346 – 1.752)

.004 – .010

(0.101 – 0.254)

.008 – .010

(0.203 – 0.254)

0°– 8° TYP

.016 – .050

(0.406 – 1.270)

.050

(1.270)

BSC

.014 – .019

(0.355 – 0.483)

TYP

NOTE:

INCHES

1. DIMENSIONS IN

(MILLIMETERS)

2. DRAWING NOT TO SCALE

3. THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS.

MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED .006" (0.15mm)

SO8 0303

3021fa

Information furnished by Linear Technology Corporation is believed to be accurate and reliable.

However, no responsibility is assumed for its use. Linear Technology Corporation makes no represen-

tationthattheinterconnectionofitscircuitsasdescribedhereinwillnotinfringeonexistingpatentrights.

15

LT3021/LT3021-1.2/

LT3021-1.5/LT3021-1.8

RELATED PARTS

PART NUMBER

DESCRIPTION

COMMENTS

LT1121/LT1121HV

150mA, Micropower LDOs

V : 4.2V to 30V/36V, V : 3.75V to 30V, V = 0.42V, I = 30µA,

SD

IN

OUT

DO

Q

I

= 16µA, Reverse-Battery Protection, SOT-223, S8, Z Packages

LT1129

LT1761

700mA, Micropower LDO

V : 4.2V to 30V, V : 3.75V to 30V, V = 0.4V, I = 50µA, I = 16µA,

IN OUT DO Q SD

DD, SOT-223, S8, TO220-5, TSSOP20 Packages

100mA, Low Noise Micropower LDO

V : 1.8V to 20V, V : 1.22V to 20V, V = 0.3V, I = 20µA, I < 1µA,

IN OUT DO Q SD

Low Noise: < 20µV

ThinSOT Package

, Stable with 1µF Ceramic Capacitor,

RMSP-P

LT1762

150mA, Low Noise Micropower LDO

500mA, Low Noise Micropower LDO

3A, Low Noise, Fast Transient Response LDOs

V : 1.8V to 20V, V : 1.22V to 20V, V = 0.3V, I = 25µA, I < 1µA,

IN

OUT

DO

Q

SD

Low Noise: <20µV

, MS8 Package

RMSP-P

LT1763

V : 1.8V to 20V, V : 1.22V to 20V, V = 0.3V, I = 30µA, I < 1µA,

IN

OUT

RMSP-P

DO

Q

SD

Low Noise: < 20µV

, S8 Package

LT1764/LT1764A

V : 2.7V to 20V, V : 1.21V to 20V, V = 0.34V, I = 1mA, I < 1µA,

IN

OUT

RMSP-P

DO

Q

SD

Low Noise: <40µV

DD, TO220-5 Packages

, “A” Version Stable with Ceramic Capacitors,

LTC1844

150mA, Low Noise, Micropower VLDO

300mA, Low Noise Micropower LDO

V : 1.6V to 6.5V, V

= 1.25V, V = 0.09V, I = 35µA,

OUT(MIN) DO Q

IN

I

< 1µA, Low Noise: < 30µV

, ThinSOT Package

SD

RMS

LT1962

V : 1.8V to 20V, V : 1.22V to 20V, V = 0.27V, I = 30µA, I < 1µA,

IN

OUT

DO

Q

SD

Low Noise: < 20µV

, MS8 Package

RMSP-P

LT1963/LT1963A

1.5A, Low Noise, Fast Transient Response LDOs

V : 2.1V to 20V, V : 1.21V to 20V, V = 0.34V, I = 1mA, I < 1µA,

IN

OUT

DO

Q

SD

Low Noise: < 40µV

, “A” Version Stable with Ceramic Capacitors,

RMSP-P

DD, TO220-5, SOT223, S8 Packages

LT3010

LT3020

50mA, High Voltage, Micropower LDO

100mA, Low Voltage LDO

V : 3V to 80V, V : 1.275V to 60V, V = 0.3V, I = 30µA, I < 1µA,

IN OUT DO Q SD

Low Noise: <100µV

, Stable with 1µF Output Capacitor, Exposed

RMSP-P

MS8 Package

V : 0.9V to 10V, V : 0.2V to 5V (min), V = 0.15V, I = 120µA,

IN

OUT

DO

Q

Noise: <250µV

DFN-8, MS8 Packages

, Stable with 2.2µF Ceramic Capacitors,

RMSP-P

LTC3025

LTC3026

300mA, Low Voltage Micropower LDO

1.5A, Low Input Voltage VLDO Regulator

V : 0.9V to 5.5V, V : 0.4V to 3.6V (min), V = 0.05V, I = 54µA,

IN OUT DO Q

Stable with 1µF Ceramic Capacitors, DFN-6 Package

V : 1.14V to 3.5V (Boost Enabled), 1.14V to 5.5V (with External 5V),

IN

DO

V

= 0.1V, I = 950µA, Stable with 10µF Ceramic Capacitors, 10-Lead

Q

MSOP and DFN-10 Packages

LT3150

Low V , Fast Transient Response, VLDO Controller V : 1.1V to 10V, V : 1.21V to 10V, V = Set by External MOSFET

IN

R

OUT

DO

, 1.4MHz Boost Converter Generates Gate Drive, SSOP16 Package

DS(ON)

3021fa

LT/TP 0705 500 • PRINTED IN USA

LinearTechnology Corporation

1630 McCarthy Blvd., Milpitas, CA 95035-7417

16

●

(408) 432-1900 FAX: (408) 434-0507 www.linear.com


型号：	LT1963
厂家：	Linear
描述：	500mA, Low Voltage, Very Low Dropout Linear Regulator 500mA，低压电压，非常低压差线性稳压器稳压器
文件：	总16页 (文件大小：236K)
中文：	中文翻译
下载：	下载PDF数据表文档文件

LT1963 [Linear]

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