Analog Devices ADP1073 Datasheet

Micropower DC–DC Converter

SET

V

IN

GAIN BLOCK/
ERROR AMP

COMPARATOR

SW2

FBGND

SW1

AO

I

LIM

OSCILLATOR

DRIVER

A1

A2

212mV

REFERENCE

ADP1073

a

Adjustable and Fixed 3.3 V, 5 V, 12 V

FEATURES
Operates at Supply Voltages from 1.0 V to 30 V
Ground Current 100 mA
Works in Step-Up or Step-Down Mode
Very Few External Components Required
Low Battery Detector On-Chip
User-Adjustable Current Limit
Internal 1 A Power Switch
Fixed and Adjustable Output Voltage Versions
8-Lead DIP or SO-8 Package

APPLICATIONS
Single-Cell to 5 V Converters
Laptop and Palmtop Computers
Pagers
Cameras
Battery Backup Supplies
Cellular Telephones
Portable Instruments
4 mA–20 mA Loop Powered Instruments
Hand-Held Inventory Computers

GENERAL DESCRIPTION

The ADP1073 is part of a family of step-up/step-down switch­ing regulators that operates from an input supply voltage of as
little as 1.0 V. This extremely low input voltage allows the
ADP1073 to be used in applications requiring use of a single
cell battery as the primary power source.

The ADP1073 can be configured to operate in either step-up or
step-down mode but for input voltages greater than 3 V, the
ADP1173 is recommended.

An auxiliary gain amplifier can serve as a low battery detector or
linear regulator. Quiescent current on the ADP1073-5 is only
100 µA unloaded, making it ideal for systems where long battery
life is required.

The ADP1073 can deliver 40 mA at 5 V from an input voltage
range as low as 1.25 V, or 10 mA at 5 V from a 1.0 V input.

Current limiting is available by adding an external resistor.

V

IN

ADP1073

FUNCTIONAL BLOCK DIAGRAMS

ADP1073

SET

ADP1073-3.3
ADP1073-5
ADP1073-12

OSCILLATOR

ADP1073-3.3: R1 = 62.1kV
ADP1073-5: R1 = 40kV
ADP1073-12: R1 = 16.3kV

212mV

REFERENCE

A2

GAIN BLOCK/
ERROR AMP

A1

R1

COMPARATOR

R2

904kV

ADP1073-3.3, 5, 12

SENSEGND

DRIVER

AO

I

LIM

SW1

SW2

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.

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

ADP1073–SPECIFICATIONS

(@ TA = 08C to +708C, VIN = 1.5 V unless otherwise noted)

Parameter Conditions Symbol Min Typ Max Units

QUIESCENT CURRENT Switch Off I

QUIESCENT CURRENT, STEP-UP No Load, ADP1073-3.3 I

Q

Q

100 165 µA
100 µA

MODE CONFIGURATION ADP1073-5 100 µA

ADP1073-12, T

INPUT VOLTAGE Step-Up Mode V

Step-Up Mode, T

= +25°C 100 µA

A

= +25°C 1.0 12.6 V

A

IN

1.15 12.6 V

Step-Down Mode 30 V

COMPARATOR TRIP POINT VOLTAGE ADP1073

OUTPUT SENSE VOLTAGE ADP1073-3.3

ADP1073-5
ADP1073-12

1

2

2

2

V

OUT

200 212 222 mV

3.14 3.30 3.47 V

4.75 5.00 5.25 V

11.4 12.00 12.6 V

COMPARATOR HYSTERESIS ADP1073 5 10 mV

OUTPUT HYSTERESIS ADP1073-3.3 90 130 mV

ADP1073-5 125 250 mV
ADP1073-12 300 600 mV

OSCILLATOR FREQUENCY f

MAXIMUM DUTY CYCLE Full Load (V

FB

< V

) DC 577280 %

REF

SWITCH ON TIME t

FEEDBACK PIN BIAS CURRENT ADP1073 VFB = 0 V I

SET PIN BIAS CURRENT V

AO OUTPUT LOW I
REFERENCE LINE REGULATION 1.0 V ≤ V

SWITCH SATURATION VOLTAGE V

STEP-UP MODE T

A2 ERROR AMP GAIN R

REVERSE BATTERY CURRENT

4

CURRENT LIMIT 220 Ω Between I

= V

SET

REF

= 100 µAV

AO

≤ 1.5 V 0.35 %/V

1.5 V ≤ V

IN
MIN

V

IN

T

MIN

V

IN

T

MIN

L

T

A

T

A

IN

≤ 12 V 0.05 0.15 %/V

IN

= 1.5 V, I

to T

= 1.5 V, I

to T

= 5 V, I

to T

= 100 kΩ

= 400 mA, +25°CV

SW

MAX

= 500 mA, +25°C 400 550 mV

SW

MAX

= 1 A, +25°C 700 1000 mV

SW

MAX

3

= +25°CI

and V

LIM

IN

= +25°CI

OSC

ON

FB

I

SET

AO

CESAT

A

V

REV

LIM

14 19 24 kHz

28 38 50 µs

60 300 nA

100 220 nA

0.15 0.4 V

300 450 mV

600 mV

750 mV

1500 mV

400 1000 V/V

750 mA

400 mA

CURRENT LIMIT TEMPERATURE

COEFFICIENT –0.3 %/°C

SWITCH-OFF LEAKAGE CURRENT Measured at SW1 Pin

T

= +25°CI

A

MAXIMUM EXCURSION BELOW GND I

NOTES

1

This specification guarantees that both the high and low trip point of the comparator fall within the 200 mV to 222 mV range.

2

This specification guarantees that the output voltage of the fixed versions will always fall within the specified range. The waveform at the sense pin will exhibit a
sawtooth shape due to the comparator hysteresis.

3

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

4

The ADP1073 is guaranteed to withstand continuous application of +1.6 V applied to the GND and SW2 pins while VIN, I

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

≤ 10 µA, Switch Off

SW1

T

= +25°CV

A

LEAK

SW2

LIM

–2–

115µA

–400 –350 mV

and SW1 pins are grounded.

REV. 0

ADP1073

1
2
3
4

8
7
6
5

TOP VIEW

(Not to Scale)

ADP1073

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)

ADP1073

I

LIM

V

IN

SW1
SW2

FB (SENSE)*
SET
AO
GND

* FIXED VERSIONS

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 . . . . . . . . . . . . . . . . . . . . . . . . .–0.4 V to V

IN

Feedback Pin Voltage (ADP1073) . . . . . . . . . . . . . . . . . . . 5 V

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

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

Operating Temperature Range (A) . . . . . . . . . . 0°C to +70°C

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

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

CADDELL-BURNS

7200-12

82mH

I

V

LIM

IN

1.5V

AA CELL*

OPERATES WITH CELL VOLTAGE
*ADD 10mF DECOUPLING CAPACITOR IF BATTERY

IS MORE THAN 2 INCHES AWAY FROM ADP1073

ADP1073-5

GND

SW1

SENSE

SW2

1N5818

$1.0V

+5V
40mA

100mF
SANYO
OS-CON

Figure 1. Typical Application

ORDERING GUIDE

Output Package

Model* Voltage Options**

ADP1073AN ADJ N-8
ADP1073AR ADJ SO-8
ADP1073AN-3.3 3.3 V N-8
ADP1073AR-3.3 3.3 V SO-8
ADP1073AN-5 5 V N-8
ADP1073AR-5 5 V SO-8
ADP1073AN-12 12 V N-8
ADP1073AR-12 12 V SO-8

NOTES

**Temperature Range: 0°C to +70°C.

**N = Plastic DIP; SO = Small Outline Package.

PIN FUNCTION DESCRIPTIONS

Pin Mnemonic Function

1I

LIM

For normal conditions this pin is con­nected to V

. When a lower current

IN

limit is required, a resistor should be
connected between I

LIM

and V

IN.

Limit-

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

2V

IN

Input Voltage.

3 SW1 Collector Node of Power Transistor.

For step-down configuration, connect to

for step-up configuration, connect

V

IN;

to an inductor/diode.

4 SW2 Emitter Node of Power Transistor. For

step- down configuration, connect to
inductor/diode; for step-up configura­tion, connect to ground. Do not allow
this pin to drop more than a diode drop

below ground.
5 GND Ground.
6 AO Auxiliary Gain (GB) Output. The open

collector can sink 100 µA.
7 SET Gain Amplifier Input. The amplifier’s

positive input is connected to the SET

pin and its negative input is connected

to the 212 mV reference.
8 FB/SENSE On the ADP1073 (adjustable) version

this pin is connected to the comparator

input. On the ADP1073-3.3, ADP1073-

5 and ADP1073-12, the pin goes di-

rectly to the internal application resistor

that sets output voltage.

PIN CONFIGURATIONS

8-Lead Plastic DIP 8-Lead Small Outline Package
(N-8) (SO-8)

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 ADP1073 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–

WARNING!

ESD SENSITIVE DEVICE

ADP1073

TEMPERATURE – 8C

34.5

30

240

085

25 70

32

31.5
31

30.5

34

33.5
33

32.5

SWITCH-ON TIME – ms

–Typical Performance Characteristics

1.2

1

0.8

Volts

0.6
(SAT) –
CE

0.4

V

0.2

VIN = 5.0V

V

= 3.0V

IN

VIN = 1.0V

0

0.1 0.2 1.20.3 0.4 0.5 0.6 0.7 0.8 0.9 1 1.1
SWITCH CURRENT – Amps

V

IN

= 1.25V

VIN = 1.5V

V

IN

= 2.0V

Figure 2. Saturation Voltage vs.
Switch Current in Step-Up Mode

1000

100

FOR VIN > 1.6V,
R

= 68V

10

OUTPUT CURRENT – mA

0

1 3.5

1.5 2 2.5 3
INPUT VOLTAGE – Volts

LIM

Figure 5. Guaranteed Minimum
Output Current at V

= 5 V vs.

OUT

Input Voltage

2

1.8
SATURATION VOLTAGE

1.6

1.4

1.2

1

0.8

0.6

0.4

SWITCH ON VOLTAGE – Volts

0.2

0

0.05

0.2 0.3 0.4 0.5 0.6

0.1 0.7

SWITCH CURRENT – Amps

Figure 3. Switch ON Voltage vs.
Switch Current in Step-Down Mode

120

110

100

90

80

70

60

SET PIN BIAS CURRENT – nA

50

40

240

085

25 70

TEMPERATURE – 8C

Figure 6. Set Pin Bias Current vs.
Temperature

1400

1200

800

600

400

200

0

10 100030

VIN = 3V
WITH L = 82mH

VIN = 1.5V
WITH L = 82mH

50

70 90 200 400 600 800

1000

SWITCH CURRENT – mA

VIN = 12V
WITH L = 150mH

R

– V

LIM

Figure 4. Maximum Switch Current
vs. R

LIM

160

140

120

100

SUPPLY CURRENT – mA

VIN = 1.5V

80

60

40

240

085

25 70

TEMPERATURE – 8C

Figure 7. Supply Current vs.
Temperature

22

21

20

19

18

17

16

15

OSCILLATOR FREQUENCY – kHz

14

240

08525 70

TEMPERATURE – 8C

Figure 8. Oscillator Frequency vs.
Temperature

70

68

66

64

62

60

DUTY CYCLE – %

58

56

240

085

25 70

TEMPERATURE – 8C

Figure 9. Duty Cycle vs. Temperature

–4–

Figure 10. Switch ON Time vs.
Temperature

REV. 0

2300

ADP1073

2100

1900

1700

1500

GAIN BLOCK GAIN – V/V

1300

1100

240

085

TEMPERATURE – 8C

Figure 11. “Gain Block” Gain vs. Temperature

THEORY OF OPERATION

The ADP1073 is a flexible, low power 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 very high performance
with low quiescent current.

A functional block diagram of the ADP1073 is shown on the
front page. The internal 212 mV reference is connected to one
input of the comparator, while the other input is externally
connected (via the FB pin) to a feedback network connected to
the regulated output. When the voltage at the FB pin falls below
212 mV, the 19 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 212 mV, the oscillator is shut off. While the oscillator is
off, the ADP1073 quiescent current is only 100 µA. The com-
parator includes a small amount of hysteresis, which 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

IN

and the I

pin. When

LIM

the maximum current is exceeded, the switch is turned OFF.
The current limit circuitry has a time delay of about 2 µs. If an
external resistor is not used, connect I
mation on I

is included in the Limiting the Switch Current

LIM

to VIN. Further infor-

LIM

section of this data sheet.
The ADP1073 internal oscillator provides 38 µs ON and 15 µs

OFF times, which is ideal for applications where the ratio be­tween V

and V

IN

is roughly a factor of three (such as gener-

OUT

ating +5 V from a single 1.5 V cell). Wider range conversions,
as well as step-down converters, can also be accomplished with
a slight loss in the maximum output power that can be obtained.

VIN = 1.5V

= 100kV

R

L

25 70

An uncommitted gain block on the ADP1073 can be connected
as a low-battery detector, linear post-regulator or undervoltage
lockout detector. The inverting input of the gain block is inter­nally connected to the 212 mV reference. The noninverting
input is available at the SET pin. A resistor divider, connected
between V

and GND with the junction connected to the SET

IN

pin, causes the AO output to go LOW when the input voltage
goes below the low battery set point. The AO output is an open
collector NPN transistor that can sink 100 µA.

The ADP1073 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 ADP1073 is set with two external
resistors. Three fixed-voltage models are also available:
ADP1073-3.3 (+3.3 V), ADP1073-5 (+5 V) and ADP1073-12
(+12 V). The fixed-voltage models are identical to the ADP1073,
except that laser-trimmed voltage-setting resistors are included
on the chip. Only three external components are required to
form a +3.3 V, +5 V or +12 V converter. On the fixed-voltage
models of the ADP1073, simply connect the feedback pin (Pin

8) directly to the output voltage.
The ADP1073 oscillator only turns on when the output voltage

is below the programmed voltage. When the output voltage is
above the programmed voltage, the ADP1073 remains in its
quiescent state to conserve power. Output ripple, which is in­herent in gated oscillator converters, is typically 125 mV for a
5 V output and 300 mV for a 12 V output. This ripple voltage
can be greatly reduced by inserting the gain-block between the
output and the FB pin. Further information and a typical circuit
are shown in the Programming the Gain Block section.

REV. 0

–5–