Analog Devices ADP1147 Datasheet

High Efficiency Step-Down

a

FEATURES
Greater Than 95% Efficiency
Current Mode Switching Architecture Provides

Superior Load and Line Transient Response
Wide Input Voltage Range 3.5 V* to 16 V
User Defined Current Limit
Short Circuit Protection
Shutdown Pin
Low Dropout Voltage
Low Standby Current 160 mA typ
Low Cost
Available in 8-Lead PDIP or 8-Lead SOIC

APPLICATIONS
Portable Computers
Modems
Cellular Telephones
Portable Equipment
GPS Systems
Handheld Instruments

GENERAL DESCRIPTION

The ADP1147 is part of a family of High Efficiency Step-Down
Switching Regulators. These regulators offer superior load and
line transient response, a user defined current limit and an
automatic power savings mode. The automatic power savings
mode is used to maintain efficiency at lower output currents.
The ADP1147 incorporates a constant off-time, current mode
switching architecture to drive an external P-channel MOSFET
at frequencies up to 250 kHz. Constant off-time switching gen­erates a constant ripple current in the external inductor. This
results in a wider input voltage operating range of 3.5 V* to
16 V, and a less complex circuit design.

*3.5 volt operation is for the ADP1147-3.3.

L

D1
30BQ040

1000pF

50mH

*

(5.2V TO 12V)

V

IN

+

1mF

0V = NORMAL

1.5V = SHUTDOWN
C

R

C

C

3300pF

1kV

C

T

470pF

+

C

IN

100mF

ADP1147

SHUTDOWN

I

TH

C

T

SHUTDOWN

V

IN

P-DRIVE

SENSE(+)

SENSE(–)

GND

P-CHANNEL

IRF7204

*COILTRONICS CTX 50–2MP
**KRL SL-1-C1-0R050J

Figure 1. High Efficiency Step-Down Converter
(Typical Application)

R

SENSE

0.05V

**

V

OUT

5V/2A

+

C

OUT

390mF

Switching Regulator Controllers

ADP1147-3.3/ADP1147-5

FUNCTIONAL BLOCK DIAGRAM

V

P-DRIVE GROUND

IN

ADP1147

2

C

V

IN

SENSE(–)

Q

10mV to 150mV

ITHSHUTDOWN

SLEEP

1

Q R

S

V

V

S

TH2

TH1

T

OFF-TIME
CONTROL

C

T

A very low dropout voltage with excellent output regulation can
be obtained by minimizing the dc resistance of the Inductor, the
R

resistor, and the R

SENSE

of the P-MOSFET. The power

DS(ON)

savings mode conserves power by reducing switching losses at
lower output currents. When the output load current falls below
the minimum required for the continuous mode the ADP1147
will automatically switch to the power savings mode. It will remain
in this mode until the inductor requires additional current or the
sleep mode is entered. In sleep mode with no load the standby
power consumption of the device is reduced to 2.0 mW typical
at V

= 10 V.

IN

For designs requiring even greater efficiencies refer to the
ADP1148 data sheet.

100

95

90

85

80

75

EFFICIENCY – %

70

65

60

1 10k10 100 1k

VIN = 6 VOLTS

VIN = 10 VOLTS

LOAD CURRENT – mA

Figure 2. ADP1147-5 Typical Efficiency, Figure 1 Circuit

SENSE(+)

V

R

B

S

13kV

V

OS

G

1.25V

REFERENCE

SENSE(–)

5pF

100kV

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., 1998

ADP1147-3.3/ADP1147-5–SPECIFICA TIONS

ELECTRICAL CHARACTERISTICS

(08C ≤ TA ≤ +708C1, VIN = 10 V, V

= 0 V unless otherwise noted)

SHUTDOWN

ADP1147

Parameter Conditions V

REGULATED OUTPUT VOLTAGE V

ADP1147-3-3 I
ADP1147-5 I

OUTPUT VOLTAGE LINE REGULATION T

= 9 V V

IN

= 700 mA 3.23 3.33 3.43 V

LOAD

= 700 mA 4.90 5.05 5.20 V

LOAD

= +25°C ∆V

A

S

OUT

OUT

Min Typ Max Units

VIN = 7 V to 12 V,
I

= 50 mA –40 0 +40 mV

LOAD

OUTPUT VOLTAGE LOAD REGULATION

ADP1147-3.3 5 mA < I
ADP1147-5 5 mA < I
Sleep Mode Output Ripple TA = +25°C, I

INPUT DC SUPPLY CURRENT

2

TA = +25°C

< 2 A ∆V

LOAD

< 2 A 60 100 mV

LOAD

= 0 A 50 mV p-p

LOAD

Normal Mode 4 V < VIN < 16 V I

OUT

Q

40 65 mV

1.6 2.3 mA
Sleep Mode (ADP1147-3.3) 4 V < VIN < 16 V 160 250 µA
Sleep Mode (ADP1147-5) 4 V < VIN < 16 V 160 250 µA
Shutdown V

CURRENT SENSE THRESHOLD VOLTAGE

ADP1147-3.3 V

SHUTDOWN

SENSE

TA = +25°C10mV
V

SENSE

= 2.1 V, 4 V < V

(–) = V
(–) = V

+

100 mV (

OUT

–

100 mV (

OUT

< 16 V 10 22 µA

IN

Forced

)

Forced

)V5–V

120 150 170 mV

4

ADP1147-5 V

SENSE

(–) = V
TA = +25°C10mV
V

(–) = V

SENSE

SHUTDOWN PIN THRESHOLD TA = +25°CV
SHUTDOWN PIN INPUT CURRENT 0 V < V

SHUTDOWN

+

100 mV (

OUT

–

100 mV (

OUT

Forced

Forced

< 8 V, VIN = 16 V I

)

) 120 150 170 mV

6

6

0.6 0.8 2 V

1.2 5 µA

TA = +25°C

PIN DISCHARGE CURRENT TA = +25°C, V

C

T

V

SENSE

(–) = V

OFF-TIME CT = 390 pF, I

DRIVER OUTPUT TRANSITION TIMES

TA = +25°C

in Regulation, 50 70 90 µA

OUT

OUT, VOUT

LOAD

= 0 V I

= 700 mA t

2

OFF

210µA

456 µs

CL = 3000 pF (Pin 8) VIN = 6 V tr, tf 100 200 ns

NOTES

1

All limits at temperature extremes are guaranteed via correlation using standard Statistical Quality Control (SQC) methods.

2

Dynamic supply current is higher due to the gate charge being delivered at the switching frequency.

Specifications subject to change without notice.

ABSOLUTE MAXIMUM RATINGS

Input Supply Voltage (Pin 1) . . . . . . . . . . . . . . 16 V to –0.3 V

Continuous Output Current (Pin 8) . . . . . . . . . . . . . . 50 mA

Sense Voltages (Pins 4, 5) . . . . . . . . . . . . . . . . 10 V to –0.3 V

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

Extended Commercial Temperature Range . . –40°C to +85°C

Junction Temperature* . . . . . . . . . . . . . . . . . . . . . . . +150°C

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

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

*TJ is calculated from the ambient temperature, TA, and power dissipation, PD,

according to the following formulas: ADP1147AN-3.3, ADP1147AN-5: TJ = TA +
(PD × 110°C/W). ADP1147AR-3.3, ADP1147AR-5: TJ = TA+(PD × 150°C/W).

Model Voltage Description Option

ADP1147AN-3.3 3.3 V Plastic DIP N-8
ADP1147AR-3.3 3.3 V SOIC SO-8
ADP1147AN-5 5 V Plastic DIP N-8
ADP1147AR-5 5 V SOIC SO-8

ORDERING GUIDE

Output Package Package

–2–

REV. 0

ADP1147-3.3/ADP1147-5

ELECTRICAL CHARACTERISTICS

(–408C ≤ T A ≤ +858C1, VIN = 10 V, unless otherwise noted)

ADP1147

Parameter Conditions V

REGULATED OUTPUT VOLTAGE V

ADP1147-3.3 I
ADP1147-5 I

= 9 V

IN

= 700 mA V

LOAD

= 700 mA 4.85 5.05 5.2 V

LOAD

S

OUT

Min Typ Max Units

3.17 3.33 3.4 V

INPUT DC SUPPLY CURRENT

Normal Mode 4 V < V

< 16 V I

IN

Q

1.6 2.6 mA
Sleep Mode (ADP1147-3.3) 4 V < VIN < 16 V 160 280 µA
Sleep Mode (ADP1147-5) 5 V < VIN < 16 V 160 280 µA
Shutdown V

SHUTDOWN

CURRENT SENSE THRESHOLD VOLTAGE

ADP1147-3.3 V

SENSE

TA = +25°C25mV
V

ADP1147-5 V

SENSE
SENSE

TA = +25°C25mV
V

SENSE

SHUTDOWN PIN THRESHOLD V
OFF-TIME CT = 390 pF, I

NOTES

1

All limits at temperature extremes are guaranteed via correlation using standard Statistical Quality Control (SQC) methods.

Specifications subject to change without notice.

= 2.1 V, 4 V < V

(–) = V
(–) = V

(–) = V
(–) = V

+

100 mV (Forced) V5–V

OUT

–

100 mV (

OUT

+

100 mV (

OUT

–

100 mV (

OUT

LOAD

< 16 V 10 28 µ A

IN

Forced

) 120 150 175 mV

Forced

)

Forced

) 120 150 175 mV

= 700 mA t

6

OFF

4

0.55 0.8 2 V

3.8 5 6 µs

PIN FUNCTION DESCRIPTIONS

Pin
No. Mnemonic Function

1V
2C

IN
T

Input Voltage.
External Capacitor Connection. This capacitor sets the operating frequency of the device. The frequency is

also dependent on the input voltage level.

3I

TH

Error Amplifier Decoupling Pin. Pin 3 voltage level causes the comparator current threshold to increase.

4 SENSE(–) This connects to internal resistive divider, which senses the output voltage. Pin 4 is also the (–) input for the

current comparator.

5 SENSE(+) This provides the + input to the current comparator. The offset between Pins 4 and 5 together with R

SENSE

establish the current trip threshold.

6 SHUTDOWN When this pin is pulled high, it keeps the MOSFET turned off. When the pin is pulled to ground, the

ADP1147 functions normally. This pin cannot be left floating.

7 GND Independent ground lines must be connected separately to (a) the negative pin of C

of the Schottky diode and the negative terminal of C

.

IN

and (b) the cathode

OUT

8 P-DRIVE Provides high current drive for the MOSFET. Voltage swing is from VIN to ground at this pin.

PIN CONFIGURATIONS

8-Lead Plastic DIP (N-8)

V

I

SENSE–

T

1

IN

ADP1147

C

2

T

TOP VIEW

3

TH

(Not to Scale)

4

= 1258C, uJA = 1108C/W

JMAX

P-DRIVE

8

GND

7
6

SHUTDOWN
SENSE+

5

8-Lead SOIC (SO-8)

V

1

IN

ADP1147

C

2

T

TOP VIEW

(Not to Scale)

I

3

TH

SENSE–

4

T

= 1258C, uJA = 1508C/W

JMAX

P-DRIVE

8

GND

7
6

SHUTDOWN

5

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 ADP1147 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.

–3–REV. 0

WARNING!

ESD SENSITIVE DEVICE

ADP1147-3.3/ADP1147-5

–Performance Characteristics

200

150

100

– mV

SENSE

R

50

0

051234

MAXIMUM OUTPUT CURRENT – Amps

Figure 3. Selecting R

SENSE

vs.

Maximum Output Current

100

GATE CHARGE

95

ADP1147 I

Q

90

EFFICIENCY – %

85

80

10m 30m 30.1 0.3 1

I

OUT

– Amps

SCHOTTKY

DIODE

I2R

Figure 6. Typical Efficiency Losses

1000

V

= V

= +5V

OUT

VIN = +10V

800

600

VIN = +12V

400

CAPACITANCE – pF

200

VIN = +7V

0

0 300100 200

FREQUENCY – kHz

SENSE

Figure 4. Operating Frequency vs.
Timing Capacitor

100

95

90

85

80

EFFICIENCY – %

75

70

0.1 AMP

58 2011 14 17

INPUT VOLTAGE – Volts

FIGURE 1 CIRCUIT

1 AMP

Figure 7. Efficiency vs. Input Voltage

1000

L = 50mH
R

= 0.02V

= 0.02V

= 0.05V

) VOLTAGE – Volts

OUT

SENSE

800

L = 25mH
R

SENSE

600

– mF

OUT

400

C

L = 50mH
R

SENSE

200

0

051 234

(VIN – V

Figure 5. Selecting Minimum Output

– V

Capacitor vs. (V

5.11

5.10

5.09

5.08

5.07
300mA

5.06

OUTPUT VOLTAGE – V

5.05

5.04

1 AMP

5.03

48 1612

IN

100mA

INPUT VOLTAGE – V

) and Inductor

OUT

FIGURE 1 CIRCUIT

Figure 8. ADP1147-5 Output Voltage
vs. Input Voltage

5.11
FIGURE 1 CIRCUIT

5.10

5.09

5.08

5.07

5.06

5.05

OUTPUT VOLTAGE – V

5.04

5.03

5.02

0 400 2000800 1200 1600

VIN = 6 VOLTS

VIN = 12 VOLTS

LOAD CURRENT – mA

Figure 9. Load Regulation

1.6

1.4

1.2

1.0

0.8

0.6

0.4

SUPPLY CURRENT – mA

0.2

0

46 208 1012141618

ACTIVE MODE

SLEEP MODE

INPUT VOLTAGE – Volts

Figure 10. DC Supply Current

40

35

V

30

25

20

15

10

SUPPLY CURRENT – mA

5

0

46 208 1012141618

= +2V

SHUTDOWN

INPUT VOLTAGE – Volts

Figure 11. Supply Current in
Shutdown

–4–

REV. 0