Analog Devices ADP3000 Datasheet

Micropower Step-Up/Step-Down

COMPARATOR

GAIN BLOCK/
ERROR AMP

400kHz

OSCILLATOR

DRIVER

A1

1.245V

REFERENCE

R1 R2

ADP3000

SET

V

IN

GND SENSE

A0
I

LIM

SW1

SW2

ADP3000-3.3V

1 2

3

8

4

5

I

LIM

V

IN

SW1

FB

(SENSE)

SW2GND

+

100µF

10V

120Ω

6.8µH

IN5817

C1
100µF
10V

V

IN

2V–3.2V

3.3V @
180mA

C1, C2: AVX TPS D107 M010R0100
L1: SUMIDA CD43-6R8

Fixed 3.3 V, 5 V, 12 V and Adjustable

a

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-Pin DIP and SO-8 Package
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 that operates from an input supply voltage of 2 V to
12 V in step-up mode and up to 30 V in step-down mode.

The ADP3000 operates in Pulse Frequency Mode (PFM) and
consumes only 500 µA, making it highly suitable for applica-
tions that require low quiescent current.

The ADP3000 can deliver an output current of 100 mA at
3 V from a 5 V input in step-down configuration and 180 mA at

3.3 V from a 2 V input in step-up configuration.
The auxiliary gain amplifier can be used as a low battery detector,

linear regulator undervoltage lockout or error amplifier.
The ADP3000 operates at 400 kHz switching frequency. This

allows the use of small external components (inductors and
capacitors), making the device very suitable for space constrained
designs.

FUNCTIONAL BLOCK DIAGRAM

Figure 1. Typical Application

V

5V–6V

IN

100µF

R

C1

120Ω

10V

C1, C2: AVX TPS D107 M010R0100
L1: SUMIDA CD43-100

LIM

1 2 3

I

LIM

ADP3000

GND

ADP3000

V

SW1

IN

8

FB

L1

10µH

4

SW2

5

1N5818

D1

100µF

10V

CL

+

R2
150kΩ
1%

R1
110kΩ
1%

V

OUT

3V
100mA

REV. 0

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
which may result from its use. No license is granted by implication or
otherwise under any patent or patent rights of Analog Devices.

Figure 2. Step-Down Mode Operation

One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: [phone] World Wide Web Site: http://www.analog.com
Fax: [phone] © Analog Devices, Inc., 1997

ADP3000–SPECIFICATIONS

(08C ≤ TA ≤ +708C, VIN = 3 V unless otherwise noted)*

ADP3000

Parameter Conditions Symbol Min Typ Max Units

INPUT VOLTAGE Step-Up Mode V

IN

2.0 12.6 V

Step-Down Mode 30.0 V

SHUTDOWN QUIESCENT CURRENT V

COMPARATOR TRIP POINT ADP3000

> 1.43 V; V

FB

> 1.1 × V

SENSE

1

OUTIQ

1.20 1.245 1.30 V

500 µA

VOLTAGE

OUTPUT SENSE VOLTAGE ADP3000-3.3

ADP3000-5
ADP3000-12

2

2

2

V

OUT

3.135 3.3 3.465 V

4.75 5.00 5.25 V

11.40 12.00 12.60 V

COMPARATOR HYSTERESIS ADP3000 8 12.5 mV

OUTPUT HYSTERESIS ADP3000-3.3 32 50 mV

ADP3000-5 32 50 mV
ADP3000-12 75 120 mV

OSCILLATOR FREQUENCY f

DUTY CYCLE V

SWITCH ON TIME I

SWITCH SATURATION VOLTAGE T

STEP-UP MODE V

> V

FB

REF

Tied to VIN, VFB = 0 t

LIM

= +25°C

A

= 3.0 V, ISW = 650 mA V

IN

V

= 5.0 V, ISW = 1 A 0.8 1.1 V

IN

OSC

D6580 %

ON

SAT

350 400 450 kHz

1.5 2 2.55 µs

0.5 0.75 V

STEP-DOWN MODE VIN = 12 V, ISW = 650 mA 1.1 1.5 V

FEEDBACK PIN BIAS CURRENT ADP3000 VFB = 0 V I

SET PIN BIAS CURRENT V

GAIN BLOCK OUTPUT LOW I

REFERENCE LINE REGULATION 5 V ≤ V

= V

SET

REF

= 300 µAV

SINK

V

= 1.00 V

SET

≤ 30 V 0.02 0.15 %/V

IN

I

FB

SET

OL

160 330 nA

200 400 nA

0.15 0.4 V

2 V ≤ VIN ≤ 5 V 0.2 0.6 %/V

GAIN BLOCK GAIN R

GAIN BLOCK CURRENT SINK V

= 100 kΩ

L

≤ 1 V I

SET

CURRENT LIMIT 220 Ω from I

3

LIM

to V

A

V

SINK

IN

I

LIM

1000 6000 V/V

300 µA

400 mA

CURRENT LIMIT TEMPERATURE

COEFFICIENT –0.3 %/°C

SWITCH OFF LEAKAGE CURRENT Measured at SW1 Pin 1 10 µA

V

= 12 V, T

SW1

MAXIMUM EXCURSION BELOW GND T

NOTES

1

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

2

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

3

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

*All limits at temperature extremes are guaranteed via correlation using standard statistical methods.
Specifications subject to change without notice.

= +25°C

A

I

≤ 10 µA, Switch Off –400 –350 mV

SW1

= +25°C

A

–2–

REV. 0

ADP3000

WARNING!

ESD SENSITIVE DEVICE

1
2
3
4

8
7
6
5

TOP VIEW

(Not to Scale)

ADP3000

I

LIM

V

IN

SW1
SW2

FB (SENSE)*
SET
AO
GND

* FIXED VERSIONS

1
2
3
4

8
7
6
5

TOP VIEW

(Not to Scale)

ADP3000

I

LIM

V

IN

SW1
SW2

FB (SENSE)*
SET
AO
GND

* FIXED VERSIONS

PIN DESCRIPTIONS

Mnemonic Function

I

LIM

For normal conditions this pin is connected to
V

. When lower current is required, a resistor

IN

should be connected between I

LIM

and V

IN.

Limiting the switch current to 400 mA is
achieved by connecting a 220 Ω resistor.

V

IN

Input Voltage.

SW1 Collector of power transistor. For step-down

configuration, connect to V

For step-up

IN.

configuration, connect to an inductor/diode.

SW2 Emitter of power transistor. For step-down

configuration, connect to inductor/diode.
For step-up configuration, connect to ground.
Do not allow this pin to go more than a diode

drop below ground.
GND Ground.
AO Auxiliary Gain (GB) output. The open col-

lector can sink 300 µA. It can be left open

if not used.
SET SET Gain amplifier input. The amplifier’s

positive input is connected to SET pin and its

negative input is connected to 1.245 V. It can

be left open if not used.
FB/SENSE On the ADP3000 (adjustable) version, this pin

is connected to the comparator input. On the

ADP3000-3.3, ADP3000-5 and ADP3000-12,

the pin goes directly to the internal resistor

divider that sets the output voltage.

ABSOLUTE MAXIMUM RATINGS

Input Supply Voltage, Step-Up Mode . . . . . . . . . . . . . . . 15 V

Input Supply Voltage, Step-Down Mode . . . . . . . . . . . . . 36 V

SW1 Pin Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50 V

SW2 Pin Voltage . . . . . . . . . . . . . . . . . . . . . . . . –0.5 V to V

Feedback Pin Voltage (ADP3000) . . . . . . . . . . . . . . . . . .5.5 V

Switch Current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1.5 A

Maximum Power Dissipation . . . . . . . . . . . . . . . . . . 500 mW

Operating Temperature Range . . . . . . . . . . . . . 0°C to +70°C

Storage Temperature Range . . . . . . . . . . . . –65°C to +150°C

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

Thermal Impedance

SO-8 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 170°C/W

N-8 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120°C/W

PIN CONFIGURATIONS

8-Lead Plastic DIP 8-Lead SOIC
(N-8) (SO-8)

ORDERING GUIDE

Output Package

Model Voltage Option

ADP3000AN-3.3 3.3 V N-8
ADP3000AR-3.3 3.3 V SO-8

ADP3000AN-5 5 V N-8
ADP3000AR-5 5 V SO-8

ADP3000AN-12 12 V N-8
ADP3000AR-12 12 V SO-8

ADP3000AN Adjustable N-8
ADP3000AR Adjustable SO-8

N = plastic DIP, SO = small outline package.

IN

SET

V

IN

1.245V

REFERENCE

A2

GAIN BLOCK/
ERROR AMP

A1

COMPARATOR

OSCILLATOR

DRIVER

A0
I

LIM

SW1

SW2

ADP3000

GND FB

Figure 3a. Functional Block Diagram for Adjustable Version

V

IN

1.245V

REFERENCE

Figure 3b. Functional Block Diagram for Fixed Version

SET

A1

GAIN BLOCK/
ERROR AMP

COMPARATOR

R1 R2

GND SENSE

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 the ADP3000 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. 0

–3–

OSCILLATOR

ADP3000

DRIVER

A0
I

LIM

SW1

SW2

ADP3000

INPUT VOLTAGE – V

1400

0

1.5 3 30

6 9 12 15 18 21 24 27

1200

1000

800

600

400

200

QUIESCENT CURRENT – µA

QUIESCENT CURRENT @ TA = +25°C

R

LIM

– Ω

SWITCH CURRENT – A

1.8

1.6

0

110 1k

100

0.6

0.2

0.4

1.0

0.8

1.4

1.2

TA = +25°C

TA = +85°C

TA = 0°C

VIN = 12V

–Typical Characteristics

2.5

2.0

1.5

1.0

ON VOLTAGE – V

0.5

0

0.1 0.2 1.5

VIN = 5V @ TA = +25°C

VIN = 3V @ TA = +25°C

VIN = 2V @ TA = +25°C

0.4 0.6 0.8 1.0 1.2 1.4
SWITCH CURRENT – A

Figure 4. Switch ON Voltage vs.
Switch Current in Step-Up Mode

406

OSCILLATOR FREQUENCY –

= +25°C

@ T

405

A

404

403

402

401

400

OSCILLATOR FREQUENCY – kHz

399

396

24 306 8 10 12 15 18 21 24 27

INPUT VOLTAGE – V

1.4

VIN = 5V @ TA = +25°C

1.2

1.0

0.8

– V

0.6

CE(SAT)

V

0.4

0.2

0.0

0.1

0.2

VIN = 12V @ TA = +25°C

0.3 0.4 0.5 0.6
SWITCH CURRENT – A

0.8

0.9

Figure 5. Saturation Voltage vs.
Switch Current in Step-Down Mode

0.8
VIN = 5V

0.7

0.6

0.5

0.4

0.3

0.2

SWITCH CURRENT – A

0.1

0

110 1k

TA = +25°C

R

– Ω

LIM

TA = +85°C

TA = 0°C

100

Figure 6. Quiescent Current vs.

Input Voltage

Figure 7. Oscillator Frequency vs.
Input Voltage

1.8
VIN = 3V

1.6

1.4

– Ω

TA = 0°C

100

1.2

TA = +25°C

1.0

0.8

0.6

SWITCH CURRENT – A

0.4

0.2

0

110 1k

Figure 8c. Maximum Switch Current
vs. R

LIM

TA = +85°C

R

LIM

in Step-Up Mode (3 V)

Figure 8a. Maximum Switch Current
vs. R

in Step-Down Mode (5 V)

LIM

440
430
420
410
400
390
380
370
360
350

OSCILLATOR FREQUENCY – kHz

340
330

–40 0 85

TEMPERATURE – °C (TA)

25 70

Figure 9. Oscillator Frequency vs.
Temperature

–4–

Figure 8b. Maximum Switch Current
vs. R

in Step-Down Mode (12 V)

LIM

2.30

2.25

2.20

2.15

2.10

2.05

2.00

ON TIME – µs

1.95

1.90

1.85

1.80
–40 0 85

TEMPERATURE – °C (TA)

25 70

Figure 10. Switch ON Time vs.
Temperature

REV. 0

ADP3000

TEMPERATURE – °C (TA)

ON VOLTAGE – V

1.25

1.20

0.90
–40 0 8525 70

1.10

1.05

1.00

0.95

1.15

VIN = 12V @ ISW = 0.65A

100

90
80
70
60
50
40

DUTY CYCLE – %

30
20
10

0

–40 0 85

TEMPERATURE – °C (TA)

25 70

Figure 11. Duty Cycle vs.

Temperature

250

200

150

100

BIAS CURRENT – µA

50

0

–40 0 85

TEMPERATURE – °C (TA)

25 70

0.56

0.54

0.52

0.50

0.48

0.46

SATURATION VOLTAGE – V

0.44

0.42
–40 0 85

VIN = 3V @ ISW = 0.65A

25 70

TEMPERATURE – °C (TA)

Figure 12. Saturation Voltage vs.
Temperature in Step-Up Mode

700

VIN = 20V

600

500

400

300

200

QUIESCENT CURRENT – µA

100

0

–40 0 8525 70

TEMPERATURE – °C (TA)

Figure 13. Switch ON Voltage vs.
Temperature in Step-Down Mode

350

300

250

200

150

100

BIAS CURRENT – µA

50

0

–40 0 8525 70

TEMPERATURE – °C (TA)

Figure 14. Feedback Bias Current

vs. Temperature

Figure 15. Quiescent Current vs.
Temperature

Figure 16. Set Pin Bias Current vs.
Temperature

REV. 0

–5–

ADP3000

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 (boost or step-up
mode) or less than the input (buck or step-down mode). This
device uses a gated oscillator technique to provide high perfor­mance with low quiescent current.

A functional block diagram of the ADP3000 is shown in
Figure 3a. The internal 1.245 V reference is connected to one
input of the comparator, while the other input is externally
connected (via the FB pin) to a resistor divider connected to
the regulated output. When the voltage at the FB pin falls below

1.245 V, the 400 kHz oscillator turns on. 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 is shut 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 can be set
by connecting a resistor between V

and the I

IN

pin. When

LIM

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

to VIN. This

LIM

yields the maximum feasible current limit. Further information
on I

is included in the “Applications” section of this data

LIM

sheet. The ADP3000 internal oscillator provides typically 1.7
µs ON and 0.8 µs OFF times.

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

and GND with the junction

IN

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 emitter of its internal power switch, which permits
both step-up and step-down modes of operation. For the step­up mode, the emitter (Pin SW2) is connected to GND and the
collector (Pin SW1) drives the inductor. For step-down 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.

APPLICATIONS INFORMATION

COMPONENT SELECTION
Inductor Selection

For most applications the inductor used with the ADP3000 will
fall in the range between 4.7 µH to 33 µH. Table I shows
recommended inductors and their vendors.

When selecting an inductor, it is very important to make sure
that the inductor used with the ADP3000 is able to handle a
current that is higher than the ADP3000’s current limit without
saturation.

As a rule of thumb, powdered iron cores saturate softly, whereas
Ferrite cores saturate abruptly. Rod or “open” drum core
geometry inductors saturate gradually. Inductors that saturate
gradually are easier to use. Even though rod or drum core
inductors are attractive in both price and physical size, these
types of inductors must be handled with care because they have
high magnetic radiation. Toroid or “closed” core geometry
should be used when minimizing EMI is critical.

In addition, inductor dc resistance causes power loss. It is best
to use low dc resistance inductors so that power loss in the
inductor is kept to the minimum. Typically, it is best to use an
inductor with a dc resistance lower than 0.2 Ω.

Table I. Recommended Inductors

V

endor Series Core Type Phone Numbers

Coiltronics OCTAPAC Toroid [phone]
Coiltronics UNIPAC Open [phone]

Sumida CD43, CD54 Open [phone]
Sumida CDRH62, CDRH73, Semi-Closed [phone]

CDRH64 Geometry

Capacitor Selection

For most applications, the capacitor used with the ADP3000
will fall in the range between 33 µF to 220 µF. Table II 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 AVX TPS series, Sprague 595D series, Panasonic HFQ
series and 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,
Sanyo OS-CON series capacitors can be used since this type of
capacitor has very low ESR. Alternatively, two or more tanta­lum capacitors can be used in parallel.

–6–

REV. 0

ADP3000

ADP3000

1.245V
REF

GND

AO

5V

R

L

47kΩ

TO
PROCESSOR

R1

V

BATT

V

IN

SET

R

HYS

R2

33kΩ

1.6MΩ

V

LB

= BATTERY TRIP POINT

R1 =

V

LB

– 1.245V

37.7µA

Table II. Recommended Capacitors

Vendor Series Type Phone Numbers

AVX TPS Surface Mount [phone]
Sanyo OS-CON Through-Hole [phone]
Sprague 595D Surface Mount [phone]
Panasonic HFQ Through-Hole [phone]

DIODE SELECTION

The ADP3000’s high switching speed demands the use of
Schottky diodes. Suitable choices include the 1N5817, 1N5818,
1N5819, MBRS120LT3 and MBR0520LT1. Do not use fast
recovery diodes because their high forward drop lowers effi­ciency. Neither general-purpose diodes nor small signal diodes
should be used.

PROGRAMMING THE SWITCHING CURRENT LIMIT
OF THE POWER SWITCH

The ADP3000’s R

pin permits the cycle by cycle switch

LIM

current limit to be programmed with a single external resistor.
This feature offers major advantages which ultimately decrease
the component cost and P.C.B. real estate. First, it allows the
ADP3000 to use low value, low saturation current and physi­cally small inductors. Additionally, it allows the ADP3000 to
use a physically small surface mount tantalum capacitor with a
typical ESR of 0.1 Ω to achieve an output ripple as low as 40
mV to 80 mV, as well as low input ripple.

As a rule of thumb, the current limit is usually set to approximately
3 to 5 times the full load current for boost applications and
about 1.5–3 times of the full load current in buck applications.

The internal structure of the I

circuit is shown in Figure 17.

LIM

Q1 is the ADP3000’s internal power switch, which 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 an internal 80 Ω resistor and the R

resistor. The voltage

LIM

on these two resistors biases the base-emitter junction of the
oscillator-disable transistor, Q3. When the voltage across R1
and R
pulse. If only the 80 Ω internal resistor is used (i.e. the I
is connected directly to V

exceeds 0.6 V, Q3 turns on and terminates the output

LIM

), the maximum switch current will

IN

LIM

pin

be 1.5 A. Figure 8a gives values for lower current-limit values.

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. Attempting to
program a switch ON time of 0.3 µs or less will produce
spurious responses in the switch ON time. However, the
ADP3000 will still provide a properly regulated output voltage.

PROGRAMMING THE GAIN BLOCK

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

Figure 18 shows the gain block configured as a low battery
monitor. Resistors R1 and R2 should be set 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 from the
formula:

LOBATT

1.245 V

–1.245 V

R2

where V

V

R1=

is the desired low battery trip point. Since the

LOBATT

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

REV. 0

R

LIM

V

IN

ADP3000

Figure 17. ADP3000 Current Limit Operation

V

IN

Q3

400kHz

OSC

(EXTERNAL)

I

R1

DRIVER

LIM

80Ω
(INTERNAL)

I

Q1

SW1

200

Q2

SW2

Q1
POWER

SWITCH

Figure 18. Setting the Low Battery Detector Trip Point

–7–

ADP3000

PD= 0.82×1+

(2)(0.8)

30











0.75

[]

1–

2

3.3











(4)0.18

0.8











+ 500E −6

[]

2

[]

The circuit of Figure 18 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,
hysteresis can be added to the circuit (Figure 18). Resistor R

HYS

,

with a value of 1 MΩ to 10 MΩ, provides the hysteresis. The
addition of R

will change the trip point slightly, so the new

HYS

value for R1 will be:

R1=

V



1.245V



R2



LOBATT



−





–1.245V



V

−1.245V

L



R



L+RHYS






where VL is the logic power supply voltage, RL is the pull-up
resistor, and R

creates the hysteresis.

HYS

POWER TRANSISTOR PROTECTION DIODE IN STEP­DOWN CONFIGURATION

When operating the ADP3000 in the step-down mode, the
output voltage is impressed across the internal power switch’s
emitter-base junction when the switch is off. In order to protect
the switch, a Schottky diode must be placed in a series with
SW2 when the output voltage is set to higher than 6 V. Figure
19 shows the proper way to place the protection diode, D2.
The selection of this diode is identical to the step-down commut­ing diode (see Diode Selection section for information).

V

IN

+

R3

C2

1 2 3

I

LIM

ADP3000

GND

D1, D2 = 1N5818 SCHOTTKY DIODES

VINSW1

5

SW2

8

FB

D2

4

D1

V

> 6V

OUT

L1

R2

+

R1

C1

Step-Down



PD= ISWV




where: ISW is I









1

1+



CESAT

in the case of current limit is programmed

LIMIT







VIN– V

β













V

O



CE SAT



()





2I

O



I

SW





+ I

V

[]

[]

Q




IN

externally or maximum inductor current in the case of
current limit is not programmed eternally.

V

= Check this value by applying ISW to Figure 8b.

CE(SAT)

1.2 V is typical value.
D = 0.75 (Typical Duty Ratio for a Single Switching

Cycle).

V

= Output Voltage.

O

= Output Current.

I

O

= Input Voltage.

V

IN

= 500 µA (Typical Shutdown Quiescent Current).

I

Q

β = 30 (Typical Forced Beta).

The temperature rise can be calculated from:

where:

∆T = PD×θ

JA

∆T = Temperature Rise.

= Device Power Dissipation.

P

D

= Thermal Resistance (Junction-to-Ambient).

θ

JA

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

VIN = 2 V, IO = 180 mA, VO = 3.3 V.
I

= 0.8 A (Externally Programmed).

SW

With Step-Up Power Dissipation Equation:

Figure 19. Step-Down Model V

OUT

> 6.0 V

THERMAL CONSIDERATIONS

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

Step-Up



PD= I




where: ISW is I

INISW

β



D 1–




V

2

R +

SW

in the case of current limit programmed

LIMIT





V

IN



V

O







4I

O

+ I

V

[]

[]

Q







I

SW







IN

externally, or maximum inductor current in the case of
current limit not programmed externally.

R = 1 Ω (Typical R

CE(SAT)

).

D = 0.75 (Typical Duty Ratio for a Single Switching
Cycle).

VO = Output Voltage.

= Output Current.

I

O

= Input Voltage.

V

IN

= 500 µA (Typical Shutdown Quiescent Current).

I

Q

β = 30 (Typical Forced Beta)

= 185 mW

Using the SO-8 Package: ∆T = 185 mW (170°C/W) = 31.5°C.
Using the N-8 Package: ∆T = 185 mW (120°C/W) = 22.2°C.
At a 70°C ambient, die temperature would be 101.45°C for

SO-8 package and 92.2°C for 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.

–8–

REV. 0

Typical Application Circuits

I

LIM V

IN

SW1

SW2

SENSE

GND

ADP3000-12V

L1

15µH

124Ω

8

1

2

45

3

1N5817

C1
100µF
10V

+

C2
100µF
16V

+

V

IN

4.5V → 5.5V

V

OUT

12V
50mA

L1 = SUMIDA CD54-150
C1 = AVX TPS D107 M010R0100
C2 = AVX TPS E107 M016R0100
TYPICAL EFFICIENCY = 75%

I

LIM

VINSW1

FB

SW2

GND

ADP3000-ADJ

C1

100µF

10V

V

IN

5V → 6V

4

1 2 3

8

5

+

L1

10µH

V

OUT

3V
100mA

+

D1

IN5817

R2
150kΩ

R1
110kΩ

C2

100µF

10V

120Ω

L1 = SUMIDA CD43-100
C1, C2 = AVX TPS D107 M010R100
TYPICAL EFFICIENCY = 75%

L1

1

GND

120Ω

6.8µH

2

IN

SW1

SENSE

SW2

45

3

8

V

IN

2V → 3.2V

+

C1
100µF
10V

I

ADP3000-3.3V

L1 = SUMIDA CD43-6R8
C1, C2 = AVX TPS D107 M010R100
TYPICAL EFFICIENCY = 75%

LIM V

1N5817

ADP3000

V

OUT

3.3V
180mA

+

C2
100µF
10V

Figure 20. 2 V to 3.3 V/180 mA Step-Up Converter

L1

6.8µH

SW1

45

3

8

1N5817

V

OUT

5V
100mA

+

C2
100µF
10V

V

IN

2V → 3.2V

+

C1
100µF
10V

120Ω

1

I

LIM

ADP3000-5V

GND

L1 = SUMIDA CD43-6R8
C1, C2 = AVX TPS D107 M010R0100
TYPICAL EFFICIENCY = 80%

2

V

IN

SENSE

SW2

Figure 21. 2 V to 5 V/100 mA Step-Up Converter

L1

6.8µH

SW1

3

8

1N5817

V

OUT

5V
150mA

+

C2
100µF
10V

V

IN

2.7V → 4.5V

+

C1
100µF
10V

1

I

LIM

ADP3000-5V

GND

L1 = SUMIDA CD43-6R8
C1, C2 = AVX TPS D107 M010R100
TYPICAL EFFICIENCY = 80%

120Ω

2

V

IN

SENSE

SW2

45

Figure 23. 4.5 V to 12 V/ 50 mA Step-Up Converter

Figure 24. 5 V to 3 V/100 mA Step-Down Converter

V

IN

10V → 13V

L1 = SUMIDA CD43-100
C1 = AVX TPS D336 M020R0200
C2 = AVX TPS D107 M010R0100
TYPICAL EFFICIENCY = 77%

33µF

20V

+

C1

250Ω

1 2 3

I

VINSW1

LIM

SENSE

8

ADP3000-5V

SW2

GND

5

IN5817

L1

10µH

4

D1

V

OUT

5V
250mA

C2

+

100µF
10V

Figure 22. 2.7 V to 5 V/150 mA Step-Up Converter

REV. 0

Figure 25. 10 V to 5 V/250 mA Step-Down Converter

–9–

ADP3000

V

IN

+

5V

C1

240Ω

47µF

16V

1 2 3

I

VINSW1

LIM

SENSE

8

ADP3000-5V

4

SW2

GND

L1 = SUMIDA CD53-150
C1 = AVX TPS D476 M016R0150
C2 = AVX TPS D107 M010R0100
TYPICAL EFFICIENCY = 60%

5

IN5817

D1

Figure 26. 5 V to –5 V/100 mA Inverter

L1

15µH

100µF

10V

+

C2

V

OUT

–5V
100mA

2.5V → 4.2V

(SUMIDA – CDRH62)

330kΩ

2N2907

100kΩ

33nF

FB

10kΩ

90kΩ

6.8µH
IN5817

348kΩ

200kΩ

1%

1%

100µF

+

10V

–

AVX-TPS

IN1

IN2

ADP3302AR1

SD

GND

+
–

100kΩ

100µF
10V
AVX-TPS

90kΩ

1MΩ

120Ω

I

SET

ADP3000

A

O

GND SW2

LIMVIN

SW1

Figure 27. 1 Cell LI-ION to 3 V/200 mA Converter with Shutdown at VIN ≤ 2.5 V

AT V

≤ 2.5V

80

75

70

% EFFICIENCY

65

2.6 3.0 3.4 3.8 4.2

= 50mA + 50mA

I

O

I

O

= 100mA + 100mA

IN

SHDN IQ = 500µA

V

IN

(V)

Figure 28. Typical Efficiency of the Circuit of Figure 27

V

O1

V

O2

1µF
6V
(MLC)

1µF
6V
(MLC)

3V
100mA

3V
100mA

–10–

REV. 0

OUTLINE DIMENSIONS

Dimensions shown in inches and (mm).

8-Lead Plastic DIP 8-Lead SOIC

(N-8) (SO-8)

ADP3000

0.210 (5.33)
MAX

0.160 (4.06)

0.115 (2.93)

0.022 (0.558)

0.014 (0.356)

0.430 (10.92)

0.348 (8.84)

8

14

PIN 1

0.100
(2.54)

BSC

5

0.280 (7.11)

0.240 (6.10)

0.060 (1.52)

0.015 (0.38)

0.070 (1.77)

0.045 (1.15)

0.130
(3.30)
MIN

SEATING
PLANE

0.325 (8.25)

0.300 (7.62)

0.015 (0.381)

0.008 (0.204)

0.195 (4.95)

0.115 (2.93)

0.1574 (4.00)

0.1497 (3.80)

PIN 1

0.0098 (0.25)

0.0040 (0.10)

SEATING

PLANE

0.1968 (5.00)

0.1890 (4.80)

8

0.0688 (1.75)

0.0532 (1.35)

0.0500

0.0192 (0.49)

(1.27)

0.0138 (0.35)

BSC

5

0.2440 (6.20)

41

0.2284 (5.80)

0.0098 (0.25)

0.0075 (0.19)

0.0196 (0.50)

0.0099 (0.25)

8°
0°

0.0500 (1.27)

0.0160 (0.41)

x 45°

REV. 0

–11–

C2223–12–1/97

–12–

PRINTED IN U.S.A.