ADP3000 Micropower Step-Up/Step-Down Fixed 3.3 V, 5 V, 12 V,

ADP3000 Micropower Step-Up/Step-Down Fixed 3.3 V, 5 V, 12 V,

Micropower Step-Up/Step-Down Fixed 3.3 V, 5 V, 12 V,

Adjustable High Frequency Switching Regulator

FEATURES

Operates at supply voltages from 2 V to 30 V

Works in step-up or step-down mode

Very few external components required

High frequency operation up to 400 kHz

Low battery detector on-chip

User-adjustable current limit

Fixed and adjustable output voltage

8-lead PDIP, 8-lead SOIC, and 14-lead TSSOP packages

Small inductors and capacitors

APPLICATIONS

Notebook, palmtop computers

Cellular telephones

Hard disk drives

Portable instruments

Pagers

GENERAL DESCRIPTION

The ADP3000 is a versatile step-up/step-down switching regulator. It operates from an input supply voltage of 2 V to

12 V in step-up mode, and from 2 V to 30 V in step-down mode.

Operating in pulse frequency mode (PFM), the device consumes only 500 µA, making it ideal for applications requiring low quiescent current. It delivers an output current of 180 mA at

3.3 V from a 2 V input in step-up mode, and an output current of 100 mA at 3 V from a 5 V input in step-down mode.

The ADP3000 operates at 400 kHz switching frequency. This allows the use of small external components (inductors and capacitors), making it convenient for space-constrained designs.

The auxiliary gain amplifier can be used as a low battery detector, linear regulator, undervoltage lockout, or error amplifier.

V

IN

ADP3000

FUNCTIONAL BLOCK DIAGRAMS

SET

1.245V

REFERENCE

A1

GAIN BLOCK/

ERROR AMP

400kHz

OSCILLATOR

COMPARATOR

DRIVER

A0

I

LIM

SW1

SW2

GND

R1

V

IN

2V TO 3.2V

100

µF

10V

R2

SENSE

ADP3000

R2

150k

1%

R1

110k

1%

V

OUT

3V

100mA

Figure 1.

6.8

µH

IN5817

3.3V

180mA

120V

1

I

LIM

2

V

IN

SW1 3

ADP3000-3.3V

FB

(SENSE)

8

GND

5

SW2

4

+

C1

100

µF

10V

C1, C2 = AVX TPS D107 M010R0100

L1 = SUMIDA CR43-6R8

Figure 2. Typical Application

V

IN

5V TO 6V

100

C1

µF

10V

R

LIM

120

1

I

LIM

2

V

IN

3

SW1

ADP3000

FB

SW2

8

4

GND

5

D1

1N5818

C1, C2 = AVX TPS D107 M010R0100

L1 = SUMIDA CR43-100

L1

10

µH

100

C

µF

10V

+

Figure 3. Step-Down Mode Operation

Rev. A

Information furnished by Analog Devices is believed to be accurate and reliable.

However, no responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other rights of third parties that may result from its use.

Specifications subject to change without notice. No license is granted by implication or otherwise under any patent or patent rights of Analog Devices. Trademarks and registered trademarks are the property of their respective owners.

One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.

Tel: 781.329.4700

Fax: 781.326.8703

www.analog.com

© 2004 Analog Devices, Inc. All rights reserved.

ADP3000

TABLE OF CONTENTS

Specifications..................................................................................... 3

Absolute Maximum Ratings............................................................ 4

ESD Caution.................................................................................. 4

Pin Configurations and Function Descriptions ........................... 5

Typical Performance Characteristics ............................................. 6

Theory of Operation ........................................................................ 9

Applications Information .............................................................. 10

Component Selection................................................................. 10

Programming the Switching Current Limit............................ 10

REVISION HISTORY

9/04—Data Sheet Changed from Rev. 0 to Rev. A

Added RU-14 Package ................................................. Universal

Changes to Table 4.....................................................................10

Changes to Table 5.....................................................................10

Updated Outline Dimensions ..................................................15

Changes to Ordering Guide .....................................................16

1/97—Revision 0: Initial Version

Programming the Gain Block................................................... 11

Power Transistor Protection Diode in Step-Down

Configuration ............................................................................. 11

Thermal Considerations............................................................ 11

Typical Application Circuits ......................................................... 13

Outline Dimensions ....................................................................... 15

Ordering Guide .......................................................................... 16

Rev. A | Page 2 of 16

ADP3000

SPECIFICATIONS

0°C ≤ T

A

≤ +70°C, V

IN

= 3 V, unless otherwise noted.

1

Table 1.

Parameter

INPUT VOLTAGE

Conditions

Step-up mode

Symbol

V

IN

Min

ADP3000

Typ Max Unit

2.0 12.6

30.0

I

Q

SHUT-DOWN QUIESCENT CURRENT

COMPARATOR TRIP POINT VOLTAGE

V

FB

> 1.43 V; V

SENSE

> 1.1 × V

OUT

ADP3000

2

OUTPUT SENSE VOLTAGE ADP3000-3.3

3

ADP3000-5

3

ADP3000-12

3

COMPARATOR HYSTERESIS

OUTPUT HYSTERESIS

ADP3000

ADP3000-3.3

V

OUT

3.135 3.3 3.465 V

4.75 5.00 5.25 V

11.40 12.00 12.60 V

ADP3000-5

ADP3000-12

8

32

12.5

50 mV mV

OSCILLATOR FREQUENCY

DUTY CYCLE V

FB

< V

REF

SWITCH-ON TIME

SWITCH SATURATION VOLTAGE

Step-Up Mode

Step-Down Mode

FEEDBACK PIN BIAS CURRENT

SET PIN BIAS CURRENT

GAIN BLOCK OUTPUT LOW

REFERENCE LINE REGULATION

I

LIM

tied to V

IN

, V

FB

= 0

T

A

= +25°C

V

IN

= 3.0 V, I

SW

= 650 mA

V

V

IN

IN

= 5.0 V, I

= 12 V, I

SW

SW

= 1 A

= 650 mA

ADP3000 V

FB

= 0 V

V

SET

= V

REF

I

SINK

= 300 µA, V

SET

= 1.00 V

5 V ≤ V

IN

≤ 30 V

GAIN BLOCK GAIN

2 V ≤ V

IN

≤ 5 V

R

L

= 100 kΩ

4

GAIN BLOCK CURRENT SINK

CURRENT LIMIT

CURRENT LIMIT TEMPERATURE COEFFICIENT

V

SET

≤ 1 V

220 Ω from I

LIM

to V

IN

I

FB

I

SET

V

OL f

OSC

350 400 450 kHz

D 65 80 % t

ON

V

SAT

0.5 0.75

0.8

1.1

V

1.1

1.5

V

V

A

V

I

SINK

I

LIM

1000 6000 V/V

%/°C

SWITCH-OFF LEAKAGE CURRENT

MAXIMUM EXCURSION BELOW GND

Measured at SW1 pin

V

SW1

= 12 V, T

A

= +25°C

T

A

= +25°C

I

SW1

≤ 10 µA, switch off

−0.3

1

−400

10

−350

µA mV

1

All limits at temperature extremes are guaranteed via correlation using standard statistical methods.

2

This specification guarantees that both the high and low trip points of the comparator fall within the 1.20 V to 1.30 V range.

3 The output voltage waveform will exhibit a saw-tooth shape due to the comparator hysteresis. The output voltage on the fixed output versions will always be within the specified range.

4

100 kΩ resistor connected between a 5 V source and the AO pin.

Rev. A | Page 3 of 16

ADP3000

ABSOLUTE MAXIMUM RATINGS

Table 2.

Parameter Rating

Input Supply Voltage, Step-Up Mode 15 V may cause permanent damage to the device. This is a stress

Input Supply Voltage, Step-Down Mode 36 V rating only; functional operation of the device at these or any

SW1 Pin Voltage

SW2 Pin Voltage

Feedback Pin Voltage (ADP3000)

50 V

−0.5 V to V

IN

5.5 V other conditions above those indicated in the operational section of this specification is not implied. Exposure to

Absolute Maximum Rating conditions for extended periods

Switch Current

Maximum Power Dissipation

Operating Temperature Range

Storage Temperature Range

1.5 A

500 mW

0°C to +70°C

−65°C to +150°C may affect device reliability.

Lead Temperature (Soldering, 10 s)

Thermal Impedance

300°C

R-8 170°C/W

RU-14 150°C/W

N-8 120°C/W

ESD CAUTION

ESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000 V readily accumulate on the human body and test equipment and can discharge without detection. Although this product features proprietary ESD protection circuitry, permanent damage may occur on devices subjected to high energy electrostatic discharges. Therefore, proper ESD precautions are recommended to avoid performance degradation or loss of functionality.

Rev. A | Page 4 of 16

PIN CONFIGURATIONS AND FUNCTION DESCRIPTIONS

I

LIM

V

IN

1

2

SW1

3

SW2

4

ADP3000

TOP VIEW

(Not to Scale)

8

7

6

5

FB (SENSE)*

SET

AO

GND

*FIXED VERSIONS

Figure 4. 8-Lead Plastic DIP (N-8)

I

LIM

V

IN

1

2

SW1

3

SW2

4

ADP3000

TOP VIEW

(Not to Scale)

8

7

6

5

FB (SENSE)*

SET

AO

GND

*FIXED VERSIONS

Figure 6. 8-Lead SOIC (R-8)

ADP3000

NC 1

NC 2

ILIM 3

VIN

4

SW1

5

NC

6

SW2 7

ADP3000

TOP VIEW

(Not to Scale)

14

NC

13 FB

12 SET

11

AO

10

NC

9

NC

8 GND

NC = NO CONNECT

Figure 5. 14-lead TSSOP (RU-14)

Table 3. Pin Function Descriptions

Mnemonic

I

LIM

V

IN

SW1

Function

For normal conditions, connect to V

IN

. When lower current is required, connect a resistor between I

To limit the switch current to 400 mA, connect a 220 Ω resistor.

LIM

and V

IN

.

Input Voltage.

SW2

GND

AO

SET

FB/SENSE

Collector of Power Transistor. For step-down configuration, connect to V

IN

. For step-up configuration, connect to an inductor/diode.

Emitter of Power Transistor. For step-down configuration, connect to inductor/diode. For step-up configuration, connect to ground. Do not allow pin to go more than a diode drop below ground.

Ground.

Auxiliary Gain Block (GB) Output. Open collector can sink 300 µA. This pin can be left open if not used.

Auxiliary Gain Amplifier Input. The amplifier’s positive input is connected to the SET pin, and its negative input is connected to the 1.245 V reference. This pin can be left open if not used.

On the ADP3000 (adjustable) version, this pin is connected to the comparator input. On the ADP3000-3.3, the ADP3000-5, and the ADP3000-12, the pin goes directly to the internal resistor divider that sets the output voltage.

SET SET

V

IN

A2

GAIN BLOCK/

ERROR AMP

A0

I

LIM

SW1

1.245V

REFERENCE

A1 OSCILLATOR

COMPARATOR

DRIVER

SW2

ADP3000

GND

FB

Figure 7. Functional Block Diagram for Adjustable Version

V

IN

A1

GAIN BLOCK/

ERROR AMP

A0

I

LIM

SW1

1.245V

REFERENCE

OSCILLATOR

COMPARATOR

DRIVER

GND

R1 R2

SENSE

ADP3000

Figure 8. Functional Block Diagram for Fixed Version

SW2

Rev. A | Page 5 of 16

ADP3000

TYPICAL PERFORMANCE CHARACTERISTICS

2.5

2.0

1.5

V

IN

= 5V @ T

A

= 25°C

1.0

V

IN

= 3V @ T

A

= 25°C

0.5

V

IN

= 2V @ T

A

= 25°C

0

0.1

0.2

0.4

0.6

0.8

1.0

SWITCH CURRENT (A)

1.2

1.4

1.5

Figure 9. Switch-On Voltage vs. Switch Current in Step-Up Mode

1.4

1.2

1.0

0.8

0.6

0.4

0.2

0

0.1

V

IN

= 5V @ T

A

= 25°C

V

IN

= 12V @ T

A

= 25°C

0.2

0.3

0.4

0.5

SWITCH CURRENT (A)

0.6

0.8

0.9

Figure 10. Saturation Voltage vs. Switch Current in Step-Down Mode

1400

1200

1000

800

600

QUIESCENT CURRENT @ T

A

= 25°C

400

200

0

1.5

3.0

6 9 12 15 18

INPUT VOLTAGE (V)

21 24 27 30

Figure 11. Quiescent Current vs. Input Voltage

403

402

401

400

399

406

405

OSCILLATOR FREQUENCY

@ T

A

= 25°C

404

398

2 4 6 8 10 12 15 18

INPUT VOLTAGE (V)

21 24 27

Figure 12. Oscillator Frequency vs. Input Voltage

30

0.4

0.3

0.2

0.1

0.8

V

IN

= 5V

0.7

0.6

0.5

T

A

= 25°C

T

A

= 85°C

T

A

= 0°C

0

1 10 100 1k

R

LIM

(

)

Figure 13. Maximum Switch Current vs. R

LIM

in Step-Down Mode (5 V)

0.6

0.4

0.2

1.8

V

IN

= 12V

1.6

1.4

1.2

1.0

0.8

T

A

= 85°C

T

A

= 25°C

T

A

= 0°C

0

1 10 100 1k

R

LIM

(

)

Figure 14. Maximum Switch Current vs. R

LIM

in Step-Down Mode (12 V)

Rev. A | Page 6 of 16

0.6

0.4

0.2

0

1

1.8

V

IN

= 3V

1.6

1.4

1.2

1.0

0.8

T

A

= 25°C

T

A

= 85°C

10 100

T

A

= 0°C

1k

R

LIM

(

)

Figure 15. Maximum Switch Current vs. R

LIM

in Step-Up Mode (3 V)

440

430

420

410

400

390

380

370

360

350

340

330

–40 0 25

TEMPERATURE (°C(T

A

))

70

Figure 16. Oscillator Frequency vs. Temperature

85

2.30

2.25

2.20

2.15

2.10

2.05

2.00

1.95

1.90

1.85

1.80

–40 0 25

TEMPERATURE (°C(T

A

))

70

Figure 17. Switch-On Time vs. Temperature

85

ADP3000

70

60

50

40

100

90

80

30

20

10

0

–40 0 25

TEMPERATURE (°C(T

A

))

70

Figure 18. Duty Cycle vs. Temperature

85

0.56

0.54

0.52

0.50

0.48

0.46

V

IN

= 3V @ I

SW

= 0.65A

0.44

0.42

–40 0 25

TEMPERATURE (°C(T

A

))

70 85

Figure 19. Saturation Voltage vs. Temperature in Step-Up Mode

1.10

1.05

1.00

0.95

1.25

1.20

1.15

V

IN

= 12V @ I

SW

= 0.65A

0.90

–40 0 25

TEMPERATURE (°C(T

A

))

70 85

Figure 20. Switch-On Voltage vs. Temperature in Step-Down Mode

Rev. A | Page 7 of 16

ADP3000

250

100

50

200

150

0

–40 0 25

TEMPERATURE (°C(T

A

))

70

Figure 21. Feedback Bias Current vs. Temperature

85

300

200

100

700

V

IN

= 20V

600

500

400

0

–40 0 25

TEMPERATURE (°C(T

A

))

70

Figure 22. Quiescent Current vs. Temperature

85

350

300

250

200

150

100

50

0

–40 0 25

TEMPERATURE (°C(T

A

))

70

Figure 23. Set Pin Bias Current vs. Temperature

85

Rev. A | Page 8 of 16

THEORY OF OPERATION

The ADP3000 is a versatile, high frequency, switch mode power supply (SMPS) controller. The regulated output voltage can be greater than the input voltage (in boost or step-up mode) or less than the input voltage (in buck or step-down mode). This device uses a gated oscillator technique to provide high performance with low quiescent current.

Figure 7 is a functional block diagram of the ADP3000. The

internal 1.245 V reference is connected to one input of the comparator, and the other input is externally connected (via the

FB pin) to a resistor divider, which is connected to the regulated output. When the voltage at the FB pin falls below 1.245 V, the

400 kHz oscillator turns on. The ADP3000 internal oscillator typically provides a 1.7 µs on time and a 0.8 µs off time. A driver amplifier provides base drive to the internal power switch, and the switching action raises the output voltage. When the voltage at the FB pin exceeds 1.245 V, the oscillator shuts off. While the oscillator is off, the ADP3000 quiescent current is only 500 µA.

The comparator’s hysteresis ensures loop stability without requiring external components for frequency compensation.

The maximum current in the internal power switch is set by connecting a resistor between V

IN

and the I

LIM

pin. When the maximum current is exceeded, the switch is turned off. The current limit circuitry has a time delay of about 0.3 µs. If an external resistor is not used, connect I

LIM

to V

IN

. This yields the maximum feasible current limit. Further information on I

LIM

is

included in the Applications Information section.

ADP3000

An uncommitted gain block on the ADP3000 can be connected as a low battery detector. The inverting input of the gain block is internally connected to the 1.245 V reference. The noninverting input is available at the SET pin. A resistor divider, connected between V

IN

and GND with the junction connected to the SET pin, causes the AO output to go low when the low battery set point is exceeded. The AO output is an open collector NPN transistor that can sink in excess of 300 µA.

The ADP3000 provides external connections for both the collector and the emitter of its internal power switch, permitting both step-up and step-down modes of operation.

For the step-up mode, the emitter (Pin SW2) is connected to

GND, and the collector (Pin SW1) drives the inductor. For stepdown mode, the emitter drives the inductor, while the collector is connected to V

IN

.

The output voltage of the ADP3000 is set with two external resistors. Three fixed voltage models are also available:

ADP3000-3.3 (3.3 V), ADP3000-5 (5 V), and ADP3000-12

(12 V). The fixed voltage models include laser-trimmed, voltage-setting resistors on the chip. On the fixed voltage models of the ADP3000, simply connect the feedback pin

(Pin 8) directly to the output voltage.

Rev. A | Page 9 of 16

ADP3000

APPLICATIONS INFORMATION

COMPONENT SELECTION

Inductor Selection

For most applications, the inductor used with the ADP3000

falls in the range of 4.7 µH to 33 µH. Table 4 shows

recommended inductors and their vendors.

When selecting an inductor for the ADP3000, it is very important to make sure the inductor is able to handle a current higher than the ADP3000’s current limit, without becoming saturated.

As a general rule, powdered iron cores saturate softly, whereas

Ferrite cores saturate abruptly. Rod and open drum core geometry inductors saturate gradually. Inductors that saturate gradually are easier to use. Even though rod and drum core inductors are attractive in both price and physical size, they must be used with care because they have high magnetic radiation. When minimizing EMI is critical, toroid and closed drum core geometry inductors should be used.

In addition, inductor dc resistance causes power loss. To minimize power loss, it is best to use an inductor with a dc resistance lower than 0.2 Ω.

Table 4. Recommended Inductors

Vendor Series

Coiltronics OCTAPAC

Coiltronics UNIPAC

Sumida CR43, CR54

Sumida

CDRH6D28,

CDRH73,

CDRH64

Core Type

Toroid

Open

Open

Semi-Closed

Geometry

Phone Number

(561) 752-5000

(561) 752-5000

(847) 545-6700

(847) 545-6700

Capacitor Selection

For most applications, the capacitor used with the ADP3000

falls in the range of 33 µF to 220 µF. Table 5 shows

recommended capacitors and their vendors.

For input and output capacitors, use low ESR type capacitors for best efficiency and lowest ripple. Recommended capacitors include the AVX TPS series, the Sprague 595D series, the

Panasonic HFQ series, and the Sanyo OS-CON series.

When selecting a capacitor, it is important to make sure the maximum capacitor ripple current rms rating is higher than the

ADP3000’s rms switching current.

It is best to protect the input capacitor from high turn-on current charging surges by derating the capacitor voltage by 2:1.

For very low input or output voltage ripple requirements, use capacitors with very low ESR, such as the Sanyo OS-CON series. Alternatively, two or more tantalum capacitors can be used in parallel.

Table 5. Recommended Capacitors

Vendor

AVX

Sanyo

Series

TPS

Type

OS-CON Through Hole

Phone Number

Surface Mount (843) 448-9411

(619) 661-6835

Sprague 595D

Panasonic HFQ

Surface Mount (603) 224-1961

Through Hole (800) 344-2112

Diode Selection

The ADP3000’s high switching speed demands the use of

Schottky diodes. Suitable choices include the 1N5817, the

1N5818, the 1N5819, the MBRS120LT3, and the MBR0520LT1.

Fast recovery diodes are not recommended because their high forward drop lowers efficiency. General-purpose and smallsignal diodes should be avoided as well.

PROGRAMMING THE SWITCHING CURRENT LIMIT

The ADP3000’s R

LIM

pin permits the cycle-by-cycle switch current limit to be programmed with a single external resistor.

This feature offers major advantages that ultimately decrease the component’s cost and the PCB’s real estate. First, the R

LIM pin allows the ADP3000 to use low value, low saturation current and physically small inductors. Additionally, it allows for a physically small surface-mount tantalum capacitor with a typical ESR of 0.1 Ω. With this capacitor, it achieves an output ripple as low as 40 mV to 80 mV, as well as a low input ripple.

The current limit is usually set to approximately 3 to 5 times the full load current for boost applications, and about 1.5 to 3 times the full load current in buck applications.

The internal structure of the I

LIM

circuit is shown in Figure 24.

Q1, the ADP3000’s internal power switch, is paralleled by sense transistor Q2. The relative sizes of Q1 and Q2 are scaled so that

IQ2 is 0.5% of IQ1. Current flows to Q2 through both the R

LIM resistor and an internal 80 Ω resistor. The voltage on these two resistors biases the base-emitter junction of the oscillator-disable transistor, Q3. When the voltage across R1 and R

LIM

exceeds 0.6 V,

Q3 turns on and terminates the output pulse. If only the 80 Ω internal resistor is used (when the I

LIM

pin is connected directly to

V

IN

), the maximum switch current is 1.5 A. Figure 13, Figure 14,

and Figure 15 give values for lower current limit levels.

R

LIM

(EXTERNAL)

V

IN

V

IN

I

LIM

ADP3000

Q3

400kHz

OSCILLATOR

DRIVER

R1

80

(INTERNAL)

I

Q1

200

SW1

Q2

Q1

POWER

SWITCH

SW2

Figure 24. ADP3000 Current Limit Operation

Rev. A | Page 10 of 16

The delay through the current limiting circuit is approximately

0.3 µs. If the switch-on time is reduced to less than 1.7 µs, accuracy of the current trip point is reduced as well. An attempt to program a switch-on time of 0.3 µs or less produces spurious responses in the switch-on time. However, the ADP3000 still provides a properly regulated output voltage.

PROGRAMMING THE GAIN BLOCK

The ADP3000’s gain block can be used as a low battery detector, an error amplifier, or a linear post regulator. It consists of an op amp with PNP inputs and an open-collector NPN output. The inverting input is internally connected to the 1.245 V reference, and the noninverting input is available at the SET pin. The NPN output transistor sinks in excess of 300 µA.

Figure 25 shows the gain block configured as a low battery

monitor. Set Resistors R1 and R2 to high values to reduce quiescent current, but not so high that bias current in the SET input causes large errors. A value of 33 kΩ for R2 is a good compromise. The value for R1 is then calculated as follows:

R1

=

V

LOBATT

1 .

245

1 .

V

245 V

R2

where V

LOBATT

is the desired low battery trip point.

Because the gain block output is an open-collector NPN, a pull-up resistor should be connected to the positive logic power supply.

5V

V

BATT

R1

ADP3000

1.245V

REF

V

IN

AO

R

L

47k

SET

TO

PROCESSOR

GND

R2

33k

R

HYS

1.6M

R1 =

V

LB

– 1.245V

37.7

µA

V

LB

= BATTERY TRIP POINT

Figure 25. Setting the Low Battery Detector Trip Point

The circuit of Figure 25 may produce multiple pulses when

approaching the trip point due to noise coupled into the SET input. To prevent multiple interrupts to the digital logic, add hysteresis to the circuit. Resistor R

HYS

, with a value of 1 MΩ to

10 MΩ, provides the hysteresis. The addition of R

HYS

alters the trip point slightly, changing the new value for R1 to

ADP3000

R1

=

⎜⎜

1 .

V

LOBATT

245

R2

V

⎟⎟

V

1

L

R

.

245

L

1

+

V

.

245

R

HYS

V

⎞ where:

V

L

is the logic power supply voltage.

R

L

is the pull-up resistor.

R

HYS

creates the hysteresis.

POWER TRANSISTOR PROTECTION DIODE IN

STEP-DOWN CONFIGURATION

When operating the ADP3000 in step-down mode with the switch off, the output voltage is impressed across the internal power switch’s emitter-base junction. When the output voltage is set to higher than 6 V, a Schottky diode must be placed in a

series with SW2 to protect the switch. Figure 26 shows the

proper way to place D2, the protection diode. The selection of this diode is identical to the step-down commuting diode (refer

to the Diode Selection section).

V

IN

C2

+

D1, D2 = 1N5818 SCHOTTKY DIODES

R3

1

I

LIM

2

V

IN

3

SW1

FB

8

ADP3000

SW2

4

GND

5

D2

D1

L1

C1

+

R2

V

OUT

> 6V

R1

Figure 26. Step-Down Mode V

OUT

> 6.0 V

THERMAL CONSIDERATIONS

Power dissipation internal to the ADP3000 can be approximated with the following equations.

Step-Up

P

D

=

I

SW

2

R

+

V

IN

β

I

SW

D

1

V

IN

V

O

4

I

O

I

SW

+

I

[ ]

Q

[ ]

IN

where:

I

SW

is I

LIMIT

when the current limit is programmed externally; otherwise, I

SW

is the maximum inductor current.

V

0

is the output voltage.

I

0

is the output current.

V

IN

is the input voltage.

R is 1 Ω (typical R

CE(SAT)

).

D is 0.75 (typical duty ratio for a single switching cycle).

I

Q

is 500 µA (typical shutdown quiescent current).

β = 30 (typical forced beta).

Rev. A | Page 11 of 16

ADP3000

Step-Down

P

D

= ⎢

I

SW

V

CESAT

⎜⎜

1

+

1

β

⎟⎟

V

IN

V

O

V

CE

(

SAT

)

2

I

I

SW

O

+

I

[ ]

Q

[ ]

IN

⎤ where:

I

SW

is I

LIMIT

when the current limit is programmed externally; otherwise, I

SW

is the maximum inductor current.

V

CE(SAT)

is 1.2 V (typical value). Check this value by applying I

SW

to Figure 10.

V

O

is the output voltage.

I

O

is the output current.

V

IN

is the input voltage.

D is 0.75 (typical duty ratio for a single switching cycle).

I

Q

is 500 µA (typical shutdown quiescent current).

β is 30 (typical forced beta).

The temperature rise can be calculated using the following equation:

T

=

P

D

× θ

JA

where:

T is temperature rise.

P

D

is device power dissipation.

θ

JA

is thermal resistance (junction-to-ambient).

For example, consider a boost converter with the following specifications:

V

IN

is 2 V.

V

O

is 3.3 V.

I

O

is 180 mA.

I

SW

is 0.8 A (externally programmed).

Using the step-up power dissipation equation:

P

D

=

⎢⎣

0 .

8

2

×

1

+

( 2 )( 0 .

8 )

30

⎥⎦

[

0 .

75

]

⎢⎣

⎡ −

2

3 .

3

⎥⎦

( 4 )

0 .

0 .

18

8

+

[

500

E

6

]

[ ]

T is 185 mW (170°C/W) = 31.5°C, using the R-8 package.

T is 185 mW (120°C/W) = 22.2°C, using the N-8 package.

At a 70°C ambient, the die temperature would be 101.45°C for the R-8 package and 92.2°C for the N-8 package. These junction temperatures are well below the maximum recommended junction temperature of 125°C.

Finally, the die temperature can be decreased up to 20% by using a large metal ground plate as ground pickup for the

ADP3000.

Rev. A | Page 12 of 16

TYPICAL APPLICATION CIRCUITS

L1

6.8

µH

V

IN

2V TO 3.2V

IN5817

C1

100

µF

+

10V

120

1

I

LIM

2

V

IN

SW1

3

ADP3000-3.3V

SENSE 8

+

C2

100

µF

10V

V

OUT

3.3V

180mA

GND

5

SW2

4

L1 = SUMIDA CR43-6R8

C1, C2 = AVX TPS D107 M010R0100

TYPICAL EFFICIENCY = 75%

Figure 27. 2 V to 3.3 V/180 mA Step-Up Converter

L1

6.8

µH

IN5817

V

IN

2V TO 3.2V

100

C1

µF

+

10V

120

1

I

LIM

2

V

IN

SW1 3

ADP3000-5V

SENSE 8

+

C2

100

µF

10V

V

OUT

5V

100mA

GND

5

SW2

4

L1 = SUMIDA CR43-6R8

C1, C2 = AVX TPS D107 M010R0100

TYPICAL EFFICIENCY = 80%

Figure 28. 2 V to 5 V/100 mA Step-Up Converter

L1

6.8

µH

IN5817

V

IN

2.7V TO 4.5V

100

C1

µF

10V

+

120

1

I

LIM

2

V

IN

SW1 3

ADP3000-5V

SENSE

8

+

C2

100

µF

10V

V

OUT

5V

150mA

GND

5

SW2

4

L1 = SUMIDA CR43-6R8

C1, C2 = AVX TPS D107 M010R0100

TYPICAL EFFICIENCY = 80%

Figure 29. 2.7 V to 5 V/150 mA Step-Up Converter

ADP3000

L1

15

µH

IN5817

V

IN

4.5V TO 5.5V

C1

100

µF

+

10V

124

1

I

LIM

2

V

IN

SW1

3

ADP3000-12V

SENSE 8

GND

5

L1 = SUMIDA CR54-150

C1 = AVX TPS D107 M010R0100

C2 = AVX TPS D107 M016R0100

TYPICAL EFFICIENCY = 75%

SW2

4

+

C2

100

µF

16V

V

OUT

12V

50mA

V

IN

5V TO 6V

C1

100

µF

10V

Figure 30. 4.5 V to 12 V/50 mA Step-Up Converter

120

1

I

LIM

2

V

IN

3

SW1

FB

ADP3000-ADJ

8

SW2

4

GND

5

D1

1N5817

L1

10

µH

C2

100

µF

10V

+

R2

150k

R1

110k

L1 = SUMIDA CR43-100

C1, C2 = AVX TPS D107 M010R0100

TYPICAL EFFICIENCY = 75%

V

OUT

3V

100mA

Figure 31. 5 V to 3 V/100 mA Step-Down Converter

V

IN

10V TO 13V

C1

33

µF

+

20V

250

1

I

LIM

2

V

IN

3

SW1

SENSE

ADP3000-5V

SW2

8

4

L1: SUMIDA CR43-100

C1 = AVX TPS D336 M020R0200

C2 = AVX TPS D107 M010R0100

TYPICAL EFFICIENCY = 77%

GND

5

D1

1N5817

L1

10

µH

+

C2

100

µF

10V

V

OUT

5V

250mA

Figure 32. 10 V to 5 V/250 mA Step-Down Converter

Rev. A | Page 13 of 16

ADP3000

V

IN

5V

C1

47

µF

16V

+

240

1

I

LIM

2

V

IN

3

SW1

SENSE

ADP3000-5V

SW2

8

4

GND

5

D1

1N5817

L1 = SUMIDA CR54-150

C1 = AVX TPS D476 M016R0150

C2 = AVX TPS D107 M010R0100

TYPICAL EFFICIENCY = 60%

L1

15

µH

+

C2

100

µF

10V

V

OUT

–5V

100mA

Figure 33. 5 V to −5 V/100 mA Inverter

2.5V TO 4.2V

100

µF

10V

+

AVX-TPS

100k

1M

120

I

LIM

V

IN

SET SW1

ADP3000

A

0

FB

GND SW2

90k

330k

100k

2N2907

10k

(SUMIDA – CDRH62)

6.8

µH

1N5817

33nF

90k

348k

1%

+

100

µF

10V

AVX-TPS

200k

1%

IN1 V

O1

IN2

ADP3302AR1

SD V

O2

GND

Figure 34. 1 Cell Li-Ion to 3 V/200 mA Converter with Shut-Down at V

IN

≤ 2.5 V

1

µF

6V (MLC)

1

µF

6V (MLC)

3V

100mA

3V

100mA

80

75

I

O

= 50mA + 50mA

@ V

IN

2.5V

SHDN IQ = 500

µA

70

I

O

= 100mA + 100mA

65

2.6

3.0

3.4

3.8

4.2

Figure 35. Typical Efficiency of the Circuit of Figure 34

VIN

(V)

Rev. A | Page 14 of 16

OUTLINE DIMENSIONS

8

0.375 (9.53)

0.365 (9.27)

0.355 (9.02)

5

0.295 (7.49)

0.285 (7.24)

0.275 (6.98)

1

4

0.180

(4.57)

MAX

0.150 (3.81)

0.130 (3.30)

0.110 (2.79)

0.022 (0.56)

0.018 (0.46)

0.014 (0.36)

0.100 (2.54)

BSC

0.015

(0.38)

MIN

SEATING

PLANE

0.060 (1.52)

0.050 (1.27)

0.045 (1.14)

0.325 (8.26)

0.310 (7.87)

0.300 (7.62)

0.150 (3.81)

0.135 (3.43)

0.120 (3.05)

0.015 (0.38)

0.010 (0.25)

0.008 (0.20)

COMPLIANT TO JEDEC STANDARDS MO-095AA

CONTROLLING DIMENSIONS ARE IN INCHES; MILLIMETER DIMENSIONS

(IN PARENTHESES) ARE ROUNDED-OFF INCH EQUIVALENTS FOR

REFERENCE ONLY AND ARE NOT APPROPRIATE FOR USE IN DESIGN

Figure 36. 8-Lead Plastic Dual In-Line Package [PDIP]

(N-8)

Dimensions shown in inches and (millimeters)

8

4.00 (0.1574)

3.80 (0.1497)

1

5.00 (0.1968)

4.80 (0.1890)

5

4

6.20 (0.2440)

5.80 (0.2284)

1.27 (0.0500)

BSC 1.75 (0.0688)

1.35 (0.0532)

0.25 (0.0098)

0.10 (0.0040)

COPLANARITY

0.10

SEATING

PLANE

0.51 (0.0201)

0.31 (0.0122)

0.25 (0.0098)

0.17 (0.0067)

0.50 (0.0196)

0.25 (0.0099)

× 45°

1.27 (0.0500)

0.40 (0.0157)

COMPLIANT TO JEDEC STANDARDS MS-012AA

CONTROLLING DIMENSIONS ARE IN MILLIMETERS; INCH DIMENSIONS

(IN PARENTHESES) ARE ROUNDED-OFF MILLIMETER EQUIVALENTS FOR

REFERENCE ONLY AND ARE NOT APPROPRIATE FOR USE IN DESIGN

Figure 37. 8-Lead Standard Small Outline Package [SOIC]

Narrow Body

(R-8)

Dimensions shown in millimeters and (inches)

ADP3000

Rev. A | Page 15 of 16

ADP3000

5.10

5.00

4.90

14 8

4.50

4.40

4.30

6.40

BSC

1 7

PIN 1

1.05

1.00

0.80

0.65

BSC

0.15

0.05

0.30

0.19

1.20

MAX

SEATING

PLANE

0.20

0.09

COPLANARITY

0.10

COMPLIANT TO JEDEC STANDARDS MO-153AB-1

0.75

0.60

0.45

Figure 38. 14-Lead Thin Shrink Small Outline Package [TSSOP]

(RU-14)

Dimensions shown in millimeters

ORDERING GUIDE

Model

ADP3000AN

ADP3000AN-3.3

ADP3000AN-5

ADP3000AN-12

ADP3000AR

ADP3000AR-REEL

ADP3000AR-3.3

ADP3000AR-3.3-REEL

Output Voltage

Adjustable

3.3 V

5 V

12 V

Adjustable

Adjustable

3.3 V

3.3 V

Temperature Range

–40°C to +85°C

–40°C to +85°C

–40°C to +85°C

–40°C to +85°C

–40°C to +85°C

–40°C to +85°C

–40°C to +85°C

–40°C to +85°C

ADP3000AR-5

ADP3000AR-5-REEL

ADP3000AR-12

ADP3000AR-12-REEL

5 V

5 V

12 V

12 V

–40°C to +85°C

–40°C to +85°C

–40°C to +85°C

–40°C to +85°C

ADP3000ARU Adjustable –40°C

ADP3000ARU-REEL Adjustable

Package Description

8-lead plastic DIP

8-lead plastic DIP

8-lead plastic DIP

8-lead plastic DIP

8-lead SOIC

8-lead SOIC

8-lead SOIC

8-lead SOIC

8-lead SOIC

8-lead SOIC

8-lead SOIC

8-lead SOIC

14-lead TSSOP

14-lead TSSOP

Package Option

N-8

N-8

N-8

N-8

R-8

R-8

R-8

R-8

R-8

R-8

R-8

R-8

RU-14

RU-14

© 2004 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners.

C00122–0–9/04(A)

Rev. A | Page 16 of 16

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